**Section 1**

**Basic Science and Evaluation** 

**1** 

*Japan* 

**Epidemiology** 

**1. Introduction** 

(Nachemson, 1992).

**2. Epidemiology of LBP** 

understand LBP and how to prevent LPB.

Low back pain (LBP) is a common problem that most people experience at some point in their lifetime. It is reported that the ranges of prevalence of LBP at a point, 1-year and over lifetime were from 4.4% to 33%, from 3.9% to 65% and from 11% to 84%, respectively (Andersson, 1999; Loney et al., 1999; Louw et al., 2007; McBeth et al., 2007; Walker, 2000). The differences of prevalence ranges can be caused by variation in areas, age, lifestyle, social situations and study methodology. In addition, the economic burden of LBP is very heavy (Brooks, 2006; Dagenais et al., 2008). It is, therefore, important for LBP patients to

LBP is a symptom of a pain which can be localised between the twelfth rib and the inferior gluteal folds (low back), with or without leg pain from various causes (Krismer & van Tulder, 2007), but is not a disease. LBP is generally classified as 'specific' or 'non-specific'. Non-specific LBP is defined as symptoms of unknown origin or without identifiable pathology, and specific LBP is defined as that caused by a specific pathophysiological mechanism, such as disc prolapse or herniated nucleus pulposus, infection, inflammatory arthopathy, turmour, osteoporosis or fracture (van Tulder & Waddell, 2005). Most cases are non-specific, but in 5%-10% of cases a specific cause is identified (Krismer & van Tulder, 2007). Though the causes of LBP are varied, these may be classified as spondylogenic, neurogenic, viscerogenic, vascular and psychogenic (Wong & Transfeldt, 2007). These causes can be attributed to non-specific and/or specific factors, and these factors combine with each other in some cases. Moreover, it is necessary to ascertain the factors causing LBP and whether it is primary or secondary LBP. We are able to treat and prevent LBP promptly when we specify the causes of LBP, though most of pathomechanism of LBP is unknown

LBP is an important health problem in both developed and developing countries (Brooks, 2006; Woolf & Pfleger 2003). LBP results in socio-economic losses, health and clinical problems, not only for individuals but also for countries, because LBP causes obstacles to work or work absence and increases economic burden of treatment and compensation.

Therefore, epidemiological study holds an important position in understanding LBP.

Epidemiology is the study of the health of human populations. Its functions are:

Akira Minematsu *Kio University,* 

## **1**

## **Epidemiology**

Akira Minematsu *Kio University, Japan* 

#### **1. Introduction**

Low back pain (LBP) is a common problem that most people experience at some point in their lifetime. It is reported that the ranges of prevalence of LBP at a point, 1-year and over lifetime were from 4.4% to 33%, from 3.9% to 65% and from 11% to 84%, respectively (Andersson, 1999; Loney et al., 1999; Louw et al., 2007; McBeth et al., 2007; Walker, 2000). The differences of prevalence ranges can be caused by variation in areas, age, lifestyle, social situations and study methodology. In addition, the economic burden of LBP is very heavy (Brooks, 2006; Dagenais et al., 2008). It is, therefore, important for LBP patients to understand LBP and how to prevent LPB.

LBP is a symptom of a pain which can be localised between the twelfth rib and the inferior gluteal folds (low back), with or without leg pain from various causes (Krismer & van Tulder, 2007), but is not a disease. LBP is generally classified as 'specific' or 'non-specific'. Non-specific LBP is defined as symptoms of unknown origin or without identifiable pathology, and specific LBP is defined as that caused by a specific pathophysiological mechanism, such as disc prolapse or herniated nucleus pulposus, infection, inflammatory arthopathy, turmour, osteoporosis or fracture (van Tulder & Waddell, 2005). Most cases are non-specific, but in 5%-10% of cases a specific cause is identified (Krismer & van Tulder, 2007). Though the causes of LBP are varied, these may be classified as spondylogenic, neurogenic, viscerogenic, vascular and psychogenic (Wong & Transfeldt, 2007). These causes can be attributed to non-specific and/or specific factors, and these factors combine with each other in some cases. Moreover, it is necessary to ascertain the factors causing LBP and whether it is primary or secondary LBP. We are able to treat and prevent LBP promptly when we specify the causes of LBP, though most of pathomechanism of LBP is unknown (Nachemson, 1992).

#### **2. Epidemiology of LBP**

LBP is an important health problem in both developed and developing countries (Brooks, 2006; Woolf & Pfleger 2003). LBP results in socio-economic losses, health and clinical problems, not only for individuals but also for countries, because LBP causes obstacles to work or work absence and increases economic burden of treatment and compensation. Therefore, epidemiological study holds an important position in understanding LBP.

Epidemiology is the study of the health of human populations. Its functions are:

Epidemiology 5

the prevalence of chronic LBP increased from 3.9% in 1992 to 10.2% in 2006 in North Carolina households in those aged21 years and older (Freburger et al., 2009). Cassidy et al. estimated the point and lifetime prevalence of LBP were 28.4% and 84.1% in Canadian aged from 20 to 69 years (Cassidy et al., 1998). In the United Kingdom (UK), Badley and Tennant reported the prevalence of back pain was 10.0% with the prevalence increasing with aging and the highest prevalence was shown in the aged 56-64 years from the survey of Calderdale population aged 16 years and older (Badley & Tennant, 1992). Hillman et al. reported the point and lifetime prevalence of LBP were 19% and 59%, respectively, in the Bradford population aged 25 years and over (Hillman et al., 1996). Ihlebaek et al. reported the prevalence of LBP in Norway and Sweden (Ihlebaek et al., 2006). They showed the point and lifetime prevalence of LBP were 9.9% and 62.4% in men and 16.8% and 59.1% in women in Norway, and 14.6% and 68.9% in men and 20.4% and 69.9% in women in Sweden, respectively (Ihlebaek et al., 2006). In Finland, about one-third of people aged over 30 years experienced back pain during the past month in the early 2000s. Clinical diagnosed back syndrome decreased from 17.6% to 10.4% in men and from 16.5% to 10.6% in women aged

The prevalence of LBP has been investigated in some systematic reviews. Andersson reported that the lifetime prevalence of back pain as over 70% and 1-year prevalence ranges from 15% to 45%, with point prevalence averaging 30% (Andersson, 1999). Hoy et al. estimated that point and 1-year prevalence of LBP ranged from 1.0% to 58.1%, with a mean of 18.1%, and ranged from 0.8% to 82.5% with a mean of 38.1%, respectively, in their systematic review (Hoy et al., 2010). They estimated the prevalence of LBP to be very widespread. Loney et al. reviewed 18 studies that were conducted 7 countries in Europe, North America and China (Loney & Stratford, 1999). They estimated the average point and 1-year prevalence were 19.2% (ranged from 4.4% to 33.0%) and 32.37% (ranged from 3.9% to 63%), respectively. In high quality studies (over 70 points methodologically), point and 1 year prevalence ranged from 13.7% to 28.7% and from 39% to 44.9%, respectively (Loney & Stratford, 1999). McBeth et al. found that point and lifetime prevalence of LBP ranged from 13% to 30% and from 51% to 84%, respectively, in the investigation using 13 selected studies (McBeth & Jones, 2007). Walker selected 30 studies of 56 studies using methodological examination (75% pass level for methodological acceptable) and reported that point prevalence ranged from 12% to 33%, 1-year prevalence ranged from 22% to 65% and lifetime prevalence ranged from 11% to 84% (Walker, 2000). Louw et al. estimated point, 1-year, and lifetime prevalence of LBP in 27 eligible studies in African countries (Louw et al., 2007). Studies in this review were conducted in 10 countries and they selected 10 South Africa studies, 7 Nigerian, 2 Tunisian and 8 from other countries. They estimated that point prevalence ranged from 16% to 59%, averaging 32% among adults in 9 methodologically sound studies, and 1-year prevalence ranged from 14% to 72%, averaging 50% among adults in 9 studies, and lifetime prevalence ranged from 28% to 74%, averaging 64% among adults in 6 studies. Point, 1-year, and lifetime prevalence of LBP potentially increased with age (Louw et al., 2007). In the study by Volinn in 1995 (Volinn, 1995), it was reported that LBP rates in high-income countries were higher than those in low-income countries. LBP rates among the selected for the high-income countries (Belgium, Germany and Sweden) were approximately twice or even higher than the low-income countries (Nepal, India, Nigeria, China, Indonesia and Philippines), especially in rural areas. Point prevalence of LBP ranged from 29% to 42% in the high-income countries and ranged from 7% to 18% in rural areas in

over 30 years in 1978-1980 and 2000-2001 (Heliovaara & Riihimaki, 2006).


In the case of LBP, epidemiology investigates the various factors of LBP included in the risk factors for LBP, the effects of prevention measures and interventions on LBP, the interaction of risk factors for LBP, time course changes of LBP, the burden of LBP, associations among this information and so on. Much epidemiological research on LBP has been conducted worldwide. This research is important in understanding the past, present and future of LBP, and epidemiological data provide much information to assist in seeking and solving the various problems related to LBP. Moreover, these data can prevent LBP by avoiding or decreasing risk factors for individuals.

The two most basic concepts of epidemiology are incidence and prevalence. Incidence is defined as the rate at which healthy people develop a new symptom or disease over a specified period of time. In contrast to incident, prevalence is a measure of the number of people in the population who have a symptom or disease at a particular point in time (Manchikanti, 2000). Therefore, it is necessary to note the methodological problems in the study of the epidemiology of LBP.

#### **2.1 Prevalence of LBP in the general population**

LBP is more common between the ages of 25 and 64 years (World health organization [WHO], 2001), though it can occur in all age ranges. The prevalence of LBP peaks between ages 35 and 55 (Andersson, 1992). This is considered to reflect the work force and high prevalence in the age between 30 and 50 is reported (European Foundation for the Improvement of Living and Working Conditions [Eurofound], 2007; Japan Industrial Safety & Health Association [JISHA], 1994). The prevalence of LBP has been investigated in many surveys, with point, annual, and lifetime prevalence generally showing that prevalence is widespread among the investigations. This indicates the variety of investigations, especially the methodology such as population (age, gender, race, number and lifestyle), region, time, period, definition of LBP and contents of questionnaires in the investigation. However, the preventive measures for LBP that are suited for regional populations can be found through the epidemiological data.

Cunningham and Kelsey reported that back trouble is a frequent problem and the prevalence of back pain symptoms is estimated to be 17.2% from the data source of The United States (US) Health and Nutrition Examination Survey, 1971-1975 (HANES I) of the US adults aged 25-74 years (Cunningham & Kelsey, 1984). Strine and Hootman reported that from National Health Interview Survey in 2002 the prevalence of LBP increase with aging and the total prevalence of LBP only was 17.0% and the prevalence of both neck and LBP was 9.3% of US adults aged 18 years and over (Strine & Hootman, 2007). In addition,

1. To discover the agent, host, and environmental factors which affect health, in order to provide the scientific basis for the prevention of disease and injury, and the promotion

2. To determine the relative importance of causes of illness, disability, and death, in order

3. To identify those sections of the population which have the greatest risk from specific causes of ill health, in order that the indicated action may be directed appropriately. 4. To evaluate the effectiveness of health programs and services in improving the health of

In the case of LBP, epidemiology investigates the various factors of LBP included in the risk factors for LBP, the effects of prevention measures and interventions on LBP, the interaction of risk factors for LBP, time course changes of LBP, the burden of LBP, associations among this information and so on. Much epidemiological research on LBP has been conducted worldwide. This research is important in understanding the past, present and future of LBP, and epidemiological data provide much information to assist in seeking and solving the various problems related to LBP. Moreover, these data can prevent LBP by avoiding or

The two most basic concepts of epidemiology are incidence and prevalence. Incidence is defined as the rate at which healthy people develop a new symptom or disease over a specified period of time. In contrast to incident, prevalence is a measure of the number of people in the population who have a symptom or disease at a particular point in time (Manchikanti, 2000). Therefore, it is necessary to note the methodological problems in the

LBP is more common between the ages of 25 and 64 years (World health organization [WHO], 2001), though it can occur in all age ranges. The prevalence of LBP peaks between ages 35 and 55 (Andersson, 1992). This is considered to reflect the work force and high prevalence in the age between 30 and 50 is reported (European Foundation for the Improvement of Living and Working Conditions [Eurofound], 2007; Japan Industrial Safety & Health Association [JISHA], 1994). The prevalence of LBP has been investigated in many surveys, with point, annual, and lifetime prevalence generally showing that prevalence is widespread among the investigations. This indicates the variety of investigations, especially the methodology such as population (age, gender, race, number and lifestyle), region, time, period, definition of LBP and contents of questionnaires in the investigation. However, the preventive measures for LBP that are suited for regional populations can be found through

Cunningham and Kelsey reported that back trouble is a frequent problem and the prevalence of back pain symptoms is estimated to be 17.2% from the data source of The United States (US) Health and Nutrition Examination Survey, 1971-1975 (HANES I) of the US adults aged 25-74 years (Cunningham & Kelsey, 1984). Strine and Hootman reported that from National Health Interview Survey in 2002 the prevalence of LBP increase with aging and the total prevalence of LBP only was 17.0% and the prevalence of both neck and LBP was 9.3% of US adults aged 18 years and over (Strine & Hootman, 2007). In addition,

of health.

to establish priorities for research and action.

the population. (Brownson, 1998).

decreasing risk factors for individuals.

study of the epidemiology of LBP.

the epidemiological data.

**2.1 Prevalence of LBP in the general population** 

the prevalence of chronic LBP increased from 3.9% in 1992 to 10.2% in 2006 in North Carolina households in those aged21 years and older (Freburger et al., 2009). Cassidy et al. estimated the point and lifetime prevalence of LBP were 28.4% and 84.1% in Canadian aged from 20 to 69 years (Cassidy et al., 1998). In the United Kingdom (UK), Badley and Tennant reported the prevalence of back pain was 10.0% with the prevalence increasing with aging and the highest prevalence was shown in the aged 56-64 years from the survey of Calderdale population aged 16 years and older (Badley & Tennant, 1992). Hillman et al. reported the point and lifetime prevalence of LBP were 19% and 59%, respectively, in the Bradford population aged 25 years and over (Hillman et al., 1996). Ihlebaek et al. reported the prevalence of LBP in Norway and Sweden (Ihlebaek et al., 2006). They showed the point and lifetime prevalence of LBP were 9.9% and 62.4% in men and 16.8% and 59.1% in women in Norway, and 14.6% and 68.9% in men and 20.4% and 69.9% in women in Sweden, respectively (Ihlebaek et al., 2006). In Finland, about one-third of people aged over 30 years experienced back pain during the past month in the early 2000s. Clinical diagnosed back syndrome decreased from 17.6% to 10.4% in men and from 16.5% to 10.6% in women aged over 30 years in 1978-1980 and 2000-2001 (Heliovaara & Riihimaki, 2006).

The prevalence of LBP has been investigated in some systematic reviews. Andersson reported that the lifetime prevalence of back pain as over 70% and 1-year prevalence ranges from 15% to 45%, with point prevalence averaging 30% (Andersson, 1999). Hoy et al. estimated that point and 1-year prevalence of LBP ranged from 1.0% to 58.1%, with a mean of 18.1%, and ranged from 0.8% to 82.5% with a mean of 38.1%, respectively, in their systematic review (Hoy et al., 2010). They estimated the prevalence of LBP to be very widespread. Loney et al. reviewed 18 studies that were conducted 7 countries in Europe, North America and China (Loney & Stratford, 1999). They estimated the average point and 1-year prevalence were 19.2% (ranged from 4.4% to 33.0%) and 32.37% (ranged from 3.9% to 63%), respectively. In high quality studies (over 70 points methodologically), point and 1 year prevalence ranged from 13.7% to 28.7% and from 39% to 44.9%, respectively (Loney & Stratford, 1999). McBeth et al. found that point and lifetime prevalence of LBP ranged from 13% to 30% and from 51% to 84%, respectively, in the investigation using 13 selected studies (McBeth & Jones, 2007). Walker selected 30 studies of 56 studies using methodological examination (75% pass level for methodological acceptable) and reported that point prevalence ranged from 12% to 33%, 1-year prevalence ranged from 22% to 65% and lifetime prevalence ranged from 11% to 84% (Walker, 2000). Louw et al. estimated point, 1-year, and lifetime prevalence of LBP in 27 eligible studies in African countries (Louw et al., 2007). Studies in this review were conducted in 10 countries and they selected 10 South Africa studies, 7 Nigerian, 2 Tunisian and 8 from other countries. They estimated that point prevalence ranged from 16% to 59%, averaging 32% among adults in 9 methodologically sound studies, and 1-year prevalence ranged from 14% to 72%, averaging 50% among adults in 9 studies, and lifetime prevalence ranged from 28% to 74%, averaging 64% among adults in 6 studies. Point, 1-year, and lifetime prevalence of LBP potentially increased with age (Louw et al., 2007). In the study by Volinn in 1995 (Volinn, 1995), it was reported that LBP rates in high-income countries were higher than those in low-income countries. LBP rates among the selected for the high-income countries (Belgium, Germany and Sweden) were approximately twice or even higher than the low-income countries (Nepal, India, Nigeria, China, Indonesia and Philippines), especially in rural areas. Point prevalence of LBP ranged from 29% to 42% in the high-income countries and ranged from 7% to 18% in rural areas in

Epidemiology 7

physical work, manual handling, lifting, bending or twisting, vibration, awkward postures, repetitive work) and psychosocial factors (e.g. work environment, job content, job dissatisfaction, social support, personal relation) (Pope et al., 1991; Andersson, 1992; Burdorf & Sorock, 1997), it can occur in various types of work settings. Therefore, occupational LBP

Musculoskeletal disorders (MSDs) are widespread in many countries and they are the single largest category of work-related illness (Punnett & Wegman, 2004). MSDs account for over 50% of occupational diseases in Europe (Eurofound, 2007), and LBP and neck pain are equally a high prevalence in MSDs. The World health organization (WHO) treats occupational and work-related disease separately, and occupational LBP is included in work-related disease (WHO, 2001). WHO defines that occupational diseases are adverse health conditions in a human being, the occurrence or severity of which is related to exposure to factors on the job or in the work environment, and reports that such factors can be physical, chemical, biological, ergonomic, psychosocial stressors and mechanical. WHO characterizes work-related diseases as multifactorial diseases which may frequently be work-related and when such diseases affect the worker they may be work-related in a number of ways: they may be partially caused by adverse working conditions; they may be aggravated, accelerated or exacerbated by workplace exposures; and they may impair working capacity (WHO, 2001). Additionally, Schilling proposed the categories of adverse environmental agents as workplace hazards and the categories of work-related disease and injury as the concept of work-related disorders which has broadened to include those categories with more understanding of the multiple causes of disease (Schilling, 1989). Occupational LBP can occur related to these workplace hazards and

Occupational LBP can be defined as the back pain caused by work-induced and related factors. Generally, physical, psychosocial and personal factors interact with the onset of

1. LBP occurring after working for the first time though there is no incidence of LBP before working, or LBP becoming worse after working even if there is onset of LBP

2. a high prevalence of LBP is seen at the same place of work and the same type of job, 3. LPB improved by measures taken in the place of work, such as improvement of

Also, occupational LBP is defined as work-specific LBP and classified as accidental and nonaccidental LBP under regulations related to workmen's compensation (Ministry of Labour, 1976). The former is injury that results from an unexpected event triggering injury during the task, and injuries of muscle, tendon, ligament and soft tissue (strains or ruptures) in the back are found. The latter, where pain arises as a result of normal activities and requirements of the task, and poor body mechanics, prolonged activity, repetitive motions,

It is, however, difficult to determine the relationship between occupational or work-related

2. sickness absence data are influenced not only by pain, but also by physical and

psychologic work factors, social factors and the insurance system,

working conditions and environment, absence and reshuffling of personnel.

occupational LBP. In Japan, Aoyama proposed occupational LBP (Aoyama, 1984) as:

is not only an individual medical problem, but also a social economic problem.

under the categories of work-related disorders.

and fatigue are major contributors to injuries.

before working,

factors and LBP because:

1. LBP is not easily defined,

the low-income countries, though point prevalence of LBP was 14% in Britain (Volinn, 1995). In the study by walker (Walker, 2000), the highest point and lifetime prevalence of LBP in developing nations were 16.5% and 50% in Yugoslavia, respectively, excluding unclear information, and the highest point and lifetime prevalence of LBP in other nations were 33% in Germany and Belgium, and 79% in New Zealand, respectively. However, prevalence of LBP in Africa is similar to that of Western countries (Louw et al., 2007). Moreover, Hestbaek et al. reviewed 36 studies (28 observational studies and 8 randomized controlled trials) and reported that point prevalence of LBP in persons with one or more previous episodes of LBP ranged from 14% to 93%, and those without a prior history of LBP ranged from 7% to 39% in 6 studies (Hestbaek et al., 2003). Hillman et al. reported that the annual incidence of LBP was 4.7% (Hillman et al., 1996) and Cassidy et al. reported the cumulative incidence of LBP was 18.6% (Cassidy et al., 2005). Hoy et al. estimated the 1 year incidence of a first-ever episode of LBP ranged from 6.3% to 15.4%, and the 1-year incidence of any episodes of LBP ranged from 1.5% to 36% (Hoy et al., 2010). Manchikanti reported the prevalence of recurrent or chronic LBP at 3, 6 and 12 months to range from 35% to 79% (Manchikanti, 2000).


Table 1. Point, period and lifetime prevalence of LBP in the general population

Point and lifetime prevalence of LBP is estimated to be 6.8% and 13.8%-17.2% in the US, 4.4%-28.7% and 84% in Canada, 14%-19% and 58%-59% in the UK, 19%-33% and 59% in Belgium, 13.7% and 62%-64% in Denmark, and 12%-31% and 31%-70% in Sweden, respectively, according to the systematic reviews (Hoy et al., 2010; Loney et al., 1999; McBeth, 2007; Walker, 2000). The prevalence of LBP decreased from 33% in 2000 to 24.7% in 2005 in Europe (Paoli & Merllie, 2001; Parent-Thirion et al., 2007). Prevalence rates of LBP are difficult to compare because of the time of sampling, the sampling technique and the actual questions asked (Andersson, 1999). Therefore, it is important to know the time-trend of LBP.

#### **2.2 Occupational LBP**

In LBP, occupational LBP has been a topic for research for a long time. Occupational LBP is an important problem for workers and nations, and various remedies have been proposed. Occupational LBP will be work-specific when considering the factors causing LBP. Since occupational LBP is caused by work-related factors, which are physical factors (e.g. heavy

the low-income countries, though point prevalence of LBP was 14% in Britain (Volinn, 1995). In the study by walker (Walker, 2000), the highest point and lifetime prevalence of LBP in developing nations were 16.5% and 50% in Yugoslavia, respectively, excluding unclear information, and the highest point and lifetime prevalence of LBP in other nations were 33% in Germany and Belgium, and 79% in New Zealand, respectively. However, prevalence of LBP in Africa is similar to that of Western countries (Louw et al., 2007). Moreover, Hestbaek et al. reviewed 36 studies (28 observational studies and 8 randomized controlled trials) and reported that point prevalence of LBP in persons with one or more previous episodes of LBP ranged from 14% to 93%, and those without a prior history of LBP ranged from 7% to 39% in 6 studies (Hestbaek et al., 2003). Hillman et al. reported that the annual incidence of LBP was 4.7% (Hillman et al., 1996) and Cassidy et al. reported the cumulative incidence of LBP was 18.6% (Cassidy et al., 2005). Hoy et al. estimated the 1 year incidence of a first-ever episode of LBP ranged from 6.3% to 15.4%, and the 1-year incidence of any episodes of LBP ranged from 1.5% to 36% (Hoy et al., 2010). Manchikanti reported the prevalence of recurrent or chronic LBP at 3, 6 and 12 months to range from 35% to 79% (Manchikanti,

number Range of prevalence (%)

Andersson, 1999 12 12.0 - 30.2 25 - 42 51.4 - 69.9

Loney et al., 1999 18 4.4 - 33.0 3.9 - 63 13.8 - 84 Louw et al., 2007 27 16 - 59 14 - 72 28 - 74 McBeth, 2007 13 13 - 30 31 - 67 51 – 84

Walker, 2000 30 12 - 33 22 - 65 11 - 84

Point and lifetime prevalence of LBP is estimated to be 6.8% and 13.8%-17.2% in the US, 4.4%-28.7% and 84% in Canada, 14%-19% and 58%-59% in the UK, 19%-33% and 59% in Belgium, 13.7% and 62%-64% in Denmark, and 12%-31% and 31%-70% in Sweden, respectively, according to the systematic reviews (Hoy et al., 2010; Loney et al., 1999; McBeth, 2007; Walker, 2000). The prevalence of LBP decreased from 33% in 2000 to 24.7% in 2005 in Europe (Paoli & Merllie, 2001; Parent-Thirion et al., 2007). Prevalence rates of LBP are difficult to compare because of the time of sampling, the sampling technique and the actual questions asked (Andersson, 1999). Therefore, it is important to know the time-trend of LBP.

In LBP, occupational LBP has been a topic for research for a long time. Occupational LBP is an important problem for workers and nations, and various remedies have been proposed. Occupational LBP will be work-specific when considering the factors causing LBP. Since occupational LBP is caused by work-related factors, which are physical factors (e.g. heavy

Hoy et al., 2010 19 1.0 - 58.1 0.8 - 82.5

countries) 14 - 42

countries) 7 - 28

Table 1. Point, period and lifetime prevalence of LBP in the general population

Point Period Lifetime

2000).

Study Studies of

Volinn, 1995 8 (high income

**2.2 Occupational LBP** 

Hestbaek et al., 2003 6 14 - 93

6 (low income

physical work, manual handling, lifting, bending or twisting, vibration, awkward postures, repetitive work) and psychosocial factors (e.g. work environment, job content, job dissatisfaction, social support, personal relation) (Pope et al., 1991; Andersson, 1992; Burdorf & Sorock, 1997), it can occur in various types of work settings. Therefore, occupational LBP is not only an individual medical problem, but also a social economic problem.

Musculoskeletal disorders (MSDs) are widespread in many countries and they are the single largest category of work-related illness (Punnett & Wegman, 2004). MSDs account for over 50% of occupational diseases in Europe (Eurofound, 2007), and LBP and neck pain are equally a high prevalence in MSDs. The World health organization (WHO) treats occupational and work-related disease separately, and occupational LBP is included in work-related disease (WHO, 2001). WHO defines that occupational diseases are adverse health conditions in a human being, the occurrence or severity of which is related to exposure to factors on the job or in the work environment, and reports that such factors can be physical, chemical, biological, ergonomic, psychosocial stressors and mechanical. WHO characterizes work-related diseases as multifactorial diseases which may frequently be work-related and when such diseases affect the worker they may be work-related in a number of ways: they may be partially caused by adverse working conditions; they may be aggravated, accelerated or exacerbated by workplace exposures; and they may impair working capacity (WHO, 2001). Additionally, Schilling proposed the categories of adverse environmental agents as workplace hazards and the categories of work-related disease and injury as the concept of work-related disorders which has broadened to include those categories with more understanding of the multiple causes of disease (Schilling, 1989). Occupational LBP can occur related to these workplace hazards and under the categories of work-related disorders.

Occupational LBP can be defined as the back pain caused by work-induced and related factors. Generally, physical, psychosocial and personal factors interact with the onset of occupational LBP. In Japan, Aoyama proposed occupational LBP (Aoyama, 1984) as:


Also, occupational LBP is defined as work-specific LBP and classified as accidental and nonaccidental LBP under regulations related to workmen's compensation (Ministry of Labour, 1976). The former is injury that results from an unexpected event triggering injury during the task, and injuries of muscle, tendon, ligament and soft tissue (strains or ruptures) in the back are found. The latter, where pain arises as a result of normal activities and requirements of the task, and poor body mechanics, prolonged activity, repetitive motions, and fatigue are major contributors to injuries.

It is, however, difficult to determine the relationship between occupational or work-related factors and LBP because:


Epidemiology 9

specific back pain: best estimates suggest that the prevalence is approximately 23%; 11%- 12% of population are disabled by LBP (The COST B13 Working Group, 2004a). Recurrent and chronic back pain is widely acknowledged to account for a substantial proportion of total worker absenteeism. About half of days lost due to absenteeism are accounted for by the 85% of people away from work for short periods (<7 days), whilst the other half is accounted for by the 15% who are off work for >1 month; this is reflected in the social costs of back pain, where some 80% of the health care and social costs are for the 10% with

Occupational LBP can occur in all workers in all types of job, though the prevalence varies according to the type of job. Generally, agricultural workers, construction workers, drivers, mine workers and nursing aids show high prevalence (Behrens et al., 1994; Guo et al., 1995; JISHA, 1994; Parent-Thirion et al., 2007), and the variety of prevalence by job type is considered to depend on the kinds, frequency, time, duration and intensity of occupational exposure. It is considered that many causes of LBP exist in work with a high prevalence of

 A B C D E F G H I J K L total Men 43.8 28.0 24.7 39.2 21.0 20.0 31.4 9.7 16.6 19.7 19.6 21.1 27.0 Women 54.4 31.2 17.2 17.7 18.7 24.9 17.5 14.6 16.7 19.7 22.4 21.2 23.6 Total 47.0 29.0 23.3 37.0 19.8 22.2 27.9 11.9 16.6 19.7 21.7 21.2 25.6

LBP. Table 2 shows the reported backache by sector and gender (Eurofound, 2007).

A: Agriculture and fishing, B: Manufacturing and minig, C: Electricity, gas and water supply,

G: Transport and communication, H: Financial intermediation, I: Real estate and business servise,

It is reported that the ranges of a point or annual prevalence of LBP were from 27% to 75% for farmers (Kumudini & Hasegawa, 2009; Liu et al., 2011; Milosavljevic et al., 2011; O'Sullivan et al., 2009; Taechasubamorn et al., 2011), from 44% to 74% for drivers (Alperovitch-Najenson , 2010; Bovenzi, 2009; Rozali et al., 2009), from 32% to 78% for mine workers (Bio et al., 2007; Sarikaya et al., 2007), from 20% to 23% for construction workers (Inaba et al., 2007, 2009), from 46% to 83% for care workers (Jensen et al., 2009; Minematsu, 2007; Sorensen et al., 2011; Yalcinkaya et al., 2010) in recent studies. Guo et al. reported the highest risk of back pain was among construction workers (22.6%) for men and among nursing aides (18.8%) for women (Guo et al., 1995). It is considered that the prevalence of

Prevalence and incidence of occupational LBP are different according to age, gender, type of job, nations and methods of investigation. High physical and high psychosocial exposures increase the risk of symptoms of back disorder (Devereux et al., 1999). It is considered that long working time or experience increases the risk of LBP because occupational exposure time and occupational impact have a negative effect. It is reported that prevalence of back pain in full-time workers is 25.3% compared with 19.1% in part-time workers, and the prevalence of back pain is more than 23% among workers who worked over 36 hours weekly and more than 38% among workers who worked over 45 hours weekly (Eurofound, 2007). In a study of LBP

D: Construction, E: Wholesale and retail trade, F: Hotels and restaurants,

Table 2. Reported backache by sector and gender (Eurofound, 2007)

LBP is highest in workers exposed to many occupational risk factors.

**2.2.2 Onset of accidental LBP** 

J: Public administration, K: Education and health, L: Other service.

chronic pain and disability (The COST B13 Working Group, 2004b).


In Europe, definitions of work-related MSDs are different between countries and there are some nations that lack any definitions of work-related MSDs, nevertheless, the social security institutions in these countries do provide a list of occupational diseases that entitle workers reporting such conditions to compensation (Eurofound, 2007). It is proposed that occupational LBP not be dealt with via compensation or suits, but via prevention and prevention of recurrence through work-related factors, because occupational LBP has become the major cause of work absence causing damage not only to an individual with occupational LBP and his family, but also to a country (Kurihara, 1994). Therefore, it is very important to take measures related to occupational LBP and its recurrence.

#### **2.2.1 Prevalence of occupational LBP**

Much epidemiological research on LBP has been conducted worldwide. This research is important to understand the past, present and future of LBP, and in obtaining epidemiological data providing much information in helping to seek and solve various problems of LBP. LBP is more common between the ages of 25 and 64 years (WHO 2001). The lifetime prevalence of back pain is reported as over 70% in industrialised countries, and 1-year prevalence varies between 15% and 45% (Andersson, 1999). The incidence of back pain has been reported to be approximately 5% per year (Hoogendoorn, 1999).

In Europe, MSDs represent more than 50% of serious work-related diseases, with a prevalence rate of over 2.5% among employees (more than 4 million employees), (Eurofound, 2007), and 1 in every 4 workers cites problems with backache (Parent-Thirion et al., 2007). However, prevalence of LBP decreased from 33% in 2000 to 24.7% in 2005 in Europe (Paoli & Merllie, 2001; Parent-Thirion et al., 2007). The trend of backache as a musculoskeletal disorder shows an increase in Spain and stability in the Netherlands and Norway (Eurofound, 2007). In the Netherlands, 12-month period prevalence of low back problems was 44.4% in men and 48.2% in women of the working population; about 12% of them had activity limitation (Picavet et al., 1999) and LBP was the most frequent musculoskeletal pain (point prevalence is 26.9%), (Picavet & Schouten, 2003). In UK, 40% of adults reported back pain in the previous 12 months and 15% of adults suffered from back pain throughout the year. 5% of working people with back pain had taken time off work (Department Health, 1999). In the US, about 2% of the US workers were compensated for back injuries each year (Andersson, 1999). The prevalence of back pain in working people was 17.6% in 1988 (Guo et al., 1995). Ghaffari et al. reported that 1-year prevalence was 20% in men and 27% in women, and 1-year incidence of disabling LBP was 2.1% in Iranian industrial workers (Ghaffari et al., 2006a, 2006b). Guo et al. reported that 1-year prevalence was 18.3% in men and 19.7% in women in workers in Taiwan (Guo et al., 2004). It is estimated that 2%-5% of industrial workers experience LBP each year (WHO 2001). Acute low back pain is usually considered to be self-limiting and 90% of LBP recover within 6 weeks, but 2%-7% of people develop chronic pain (The COST B13 Working Group, 2004b). After an initial episode of LBP, 44%-78% people suffer relapses of pain occur 26%-37%, relapses of work absence (The COST B13 Working Group, 2004a). Therefore, it is considered that many people suffered from chronic LBP and this affected individual and socialeconomic activities. There is little scientific evidence on the prevalence of chronic non-

In Europe, definitions of work-related MSDs are different between countries and there are some nations that lack any definitions of work-related MSDs, nevertheless, the social security institutions in these countries do provide a list of occupational diseases that entitle workers reporting such conditions to compensation (Eurofound, 2007). It is proposed that occupational LBP not be dealt with via compensation or suits, but via prevention and prevention of recurrence through work-related factors, because occupational LBP has become the major cause of work absence causing damage not only to an individual with occupational LBP and his family, but also to a country (Kurihara, 1994). Therefore, it is very

Much epidemiological research on LBP has been conducted worldwide. This research is important to understand the past, present and future of LBP, and in obtaining epidemiological data providing much information in helping to seek and solve various problems of LBP. LBP is more common between the ages of 25 and 64 years (WHO 2001). The lifetime prevalence of back pain is reported as over 70% in industrialised countries, and 1-year prevalence varies between 15% and 45% (Andersson, 1999). The incidence of back

In Europe, MSDs represent more than 50% of serious work-related diseases, with a prevalence rate of over 2.5% among employees (more than 4 million employees), (Eurofound, 2007), and 1 in every 4 workers cites problems with backache (Parent-Thirion et al., 2007). However, prevalence of LBP decreased from 33% in 2000 to 24.7% in 2005 in Europe (Paoli & Merllie, 2001; Parent-Thirion et al., 2007). The trend of backache as a musculoskeletal disorder shows an increase in Spain and stability in the Netherlands and Norway (Eurofound, 2007). In the Netherlands, 12-month period prevalence of low back problems was 44.4% in men and 48.2% in women of the working population; about 12% of them had activity limitation (Picavet et al., 1999) and LBP was the most frequent musculoskeletal pain (point prevalence is 26.9%), (Picavet & Schouten, 2003). In UK, 40% of adults reported back pain in the previous 12 months and 15% of adults suffered from back pain throughout the year. 5% of working people with back pain had taken time off work (Department Health, 1999). In the US, about 2% of the US workers were compensated for back injuries each year (Andersson, 1999). The prevalence of back pain in working people was 17.6% in 1988 (Guo et al., 1995). Ghaffari et al. reported that 1-year prevalence was 20% in men and 27% in women, and 1-year incidence of disabling LBP was 2.1% in Iranian industrial workers (Ghaffari et al., 2006a, 2006b). Guo et al. reported that 1-year prevalence was 18.3% in men and 19.7% in women in workers in Taiwan (Guo et al., 2004). It is estimated that 2%-5% of industrial workers experience LBP each year (WHO 2001). Acute low back pain is usually considered to be self-limiting and 90% of LBP recover within 6 weeks, but 2%-7% of people develop chronic pain (The COST B13 Working Group, 2004b). After an initial episode of LBP, 44%-78% people suffer relapses of pain occur 26%-37%, relapses of work absence (The COST B13 Working Group, 2004a). Therefore, it is considered that many people suffered from chronic LBP and this affected individual and socialeconomic activities. There is little scientific evidence on the prevalence of chronic non-

5. there is poor relationship between tissue injury and disability (Pope et al., 1991).

important to take measures related to occupational LBP and its recurrence.

pain has been reported to be approximately 5% per year (Hoogendoorn, 1999).

3. the healthy worker effect may bias data, 4. exposure is difficult to determine, and

**2.2.1 Prevalence of occupational LBP** 

specific back pain: best estimates suggest that the prevalence is approximately 23%; 11%- 12% of population are disabled by LBP (The COST B13 Working Group, 2004a). Recurrent and chronic back pain is widely acknowledged to account for a substantial proportion of total worker absenteeism. About half of days lost due to absenteeism are accounted for by the 85% of people away from work for short periods (<7 days), whilst the other half is accounted for by the 15% who are off work for >1 month; this is reflected in the social costs of back pain, where some 80% of the health care and social costs are for the 10% with chronic pain and disability (The COST B13 Working Group, 2004b).

Occupational LBP can occur in all workers in all types of job, though the prevalence varies according to the type of job. Generally, agricultural workers, construction workers, drivers, mine workers and nursing aids show high prevalence (Behrens et al., 1994; Guo et al., 1995; JISHA, 1994; Parent-Thirion et al., 2007), and the variety of prevalence by job type is considered to depend on the kinds, frequency, time, duration and intensity of occupational exposure. It is considered that many causes of LBP exist in work with a high prevalence of LBP. Table 2 shows the reported backache by sector and gender (Eurofound, 2007).


A: Agriculture and fishing, B: Manufacturing and minig, C: Electricity, gas and water supply,

D: Construction, E: Wholesale and retail trade, F: Hotels and restaurants,

G: Transport and communication, H: Financial intermediation, I: Real estate and business servise, J: Public administration, K: Education and health, L: Other service.

Table 2. Reported backache by sector and gender (Eurofound, 2007)

It is reported that the ranges of a point or annual prevalence of LBP were from 27% to 75% for farmers (Kumudini & Hasegawa, 2009; Liu et al., 2011; Milosavljevic et al., 2011; O'Sullivan et al., 2009; Taechasubamorn et al., 2011), from 44% to 74% for drivers (Alperovitch-Najenson , 2010; Bovenzi, 2009; Rozali et al., 2009), from 32% to 78% for mine workers (Bio et al., 2007; Sarikaya et al., 2007), from 20% to 23% for construction workers (Inaba et al., 2007, 2009), from 46% to 83% for care workers (Jensen et al., 2009; Minematsu, 2007; Sorensen et al., 2011; Yalcinkaya et al., 2010) in recent studies. Guo et al. reported the highest risk of back pain was among construction workers (22.6%) for men and among nursing aides (18.8%) for women (Guo et al., 1995). It is considered that the prevalence of LBP is highest in workers exposed to many occupational risk factors.

#### **2.2.2 Onset of accidental LBP**

Prevalence and incidence of occupational LBP are different according to age, gender, type of job, nations and methods of investigation. High physical and high psychosocial exposures increase the risk of symptoms of back disorder (Devereux et al., 1999). It is considered that long working time or experience increases the risk of LBP because occupational exposure time and occupational impact have a negative effect. It is reported that prevalence of back pain in full-time workers is 25.3% compared with 19.1% in part-time workers, and the prevalence of back pain is more than 23% among workers who worked over 36 hours weekly and more than 38% among workers who worked over 45 hours weekly (Eurofound, 2007). In a study of LBP

Epidemiology 11

Fig. 1. Onset of LBP by months (JISHA, 1994)

Fig. 2. Onset of LBP by days (JISHA, 1994)

Fig. 3. Onset of LBP by hours (JISHA, 1994)

among drivers, an uncomfortable working station (Alperovitch-Najenson, 2010), long career (Szeto & Lam, 2007), high daily vibration exposure (Bovenzi, 2010), annual driving mileage (Porter & Gyi, 2002) and long daily driving time, and cumulative total hours of exposure (Tiemessen et al., 2008) tended to increase the prevalence of back troubles. Moreover, the prevalence of LBP is significantly higher in those currently or previously exposed to manual material handling and/or tiring postures (20%) compared with those never exposed to these strains (11%) in men below the retirement aged 45-59 (Plouvier et al, 2011). Walsh et al. reported that the incident of LBP was 64.5% in men and 61.4% in women, and the rates of sudden and gradual onset LBP were 32.0% in men and 26.3% in women, and 31.5% in men and 33.0% in women, respectively (Walsh et al., 1989). According to their study, the onset of LBP is similar between sudden and gradual in men, but gradual onset of LBP was higher by 7 points than the sudden onset in women. These factors can help to predict the risk of LBP and the prevention of LBP. However, there are few reports that investigate when LBP is likely to occur. As stated above, occupational LBP is separated into accidental LBP and non-accidental LBP. Since the cause of accidental LBP is clear, accidental LBP is certified as liable for worker accident compensation in many cases, as compared with non-accidental LBP.

At present conditions of the onset of accidental LBP in Japan are mentioned based on the report of a preventive measure of LBP by JISHA (JISHA, 1994) and Kuwashima, et al. (Kuwashima et al., 1997). Accidental LBP has been about 6,000 cases per 1 year, according for more than half of all occupational diseases. The survey studied 13,166 cases that were diagnosed as accidental LBP requiring an absence of 4 days or more. In the results, the number of cases per 10,000 working population is 1.5 for male (85.5%) and 0.4 for female (14.5%), respectively. The number of case per 10,000 of the working population by agespecific groups (under 19 years, every 5 years from 20 to 64 years and over 65 years) is from 1.0 to 1.3 from the age of 25 to 59 years and from 0.2 to 0.9 of the remaining age-specific groups, respectively. The onset rate of accidental LBP was about 90% from the age of 25 to 64 years. The onset of accidental LBP is the highest in July (9.1%, 1,203 cases) and the lowest in December (5.8%, 763 cases), but it is found in every month throughout the year (Figure1). Accidental LBP does not tend to occur frequently in winter season. The onset of accidental LBP by day occurs most on Mondays (20.3%) followed by Tuesdays (16.6%) (Figure 2), therefore, accidental LBP tends to occur frequently at the beginning of the week. Also, the onset rates of accidental LBP by time distinction are 11.2%, 16.6% and 14.9% from 8:01 to 9:00, from 9:01 to 10:00 and from 10:01 to 11:00, respectively (Figure 3). The onset of accidental LBP occurs most often in the morning, the rate being 43.1% between 8:00 and 11:00. Moreover, the onset of accidental LBP is more frequent in non-manufacturers (54.7%) than in manufacturers (31.7%). Specifically, traffic and transportation (22.6%), construction (14.5%), and commerce, finance and advertising (10.4%) in the non-manufacturing account for more than 10% of the onset of accidental LBP, on the other hand, mining (13.9) and cargo handling (12.3) account for more than 10 in the number of case per 10,000 of the working population. The accumulated percentage of cases of LBP by duration of employment shows about half are among those employed for less than 5 years.

It is considered that prevention measures for occupational LBP by type of job have many common parts, as the onset of accidental LBP is similar to prevalence of occupational LBP by type of job in other countries. However, as the incidence of occupational LBP in day and time might be different among countries because of life and working style, it is necessary to take prevention measures in the case of frequent occurrence of occupational LBP.

among drivers, an uncomfortable working station (Alperovitch-Najenson, 2010), long career (Szeto & Lam, 2007), high daily vibration exposure (Bovenzi, 2010), annual driving mileage (Porter & Gyi, 2002) and long daily driving time, and cumulative total hours of exposure (Tiemessen et al., 2008) tended to increase the prevalence of back troubles. Moreover, the prevalence of LBP is significantly higher in those currently or previously exposed to manual material handling and/or tiring postures (20%) compared with those never exposed to these strains (11%) in men below the retirement aged 45-59 (Plouvier et al, 2011). Walsh et al. reported that the incident of LBP was 64.5% in men and 61.4% in women, and the rates of sudden and gradual onset LBP were 32.0% in men and 26.3% in women, and 31.5% in men and 33.0% in women, respectively (Walsh et al., 1989). According to their study, the onset of LBP is similar between sudden and gradual in men, but gradual onset of LBP was higher by 7 points than the sudden onset in women. These factors can help to predict the risk of LBP and the prevention of LBP. However, there are few reports that investigate when LBP is likely to occur. As stated above, occupational LBP is separated into accidental LBP and non-accidental LBP. Since the cause of accidental LBP is clear, accidental LBP is certified as liable for worker

accident compensation in many cases, as compared with non-accidental LBP.

about half are among those employed for less than 5 years.

At present conditions of the onset of accidental LBP in Japan are mentioned based on the report of a preventive measure of LBP by JISHA (JISHA, 1994) and Kuwashima, et al. (Kuwashima et al., 1997). Accidental LBP has been about 6,000 cases per 1 year, according for more than half of all occupational diseases. The survey studied 13,166 cases that were diagnosed as accidental LBP requiring an absence of 4 days or more. In the results, the number of cases per 10,000 working population is 1.5 for male (85.5%) and 0.4 for female (14.5%), respectively. The number of case per 10,000 of the working population by agespecific groups (under 19 years, every 5 years from 20 to 64 years and over 65 years) is from 1.0 to 1.3 from the age of 25 to 59 years and from 0.2 to 0.9 of the remaining age-specific groups, respectively. The onset rate of accidental LBP was about 90% from the age of 25 to 64 years. The onset of accidental LBP is the highest in July (9.1%, 1,203 cases) and the lowest in December (5.8%, 763 cases), but it is found in every month throughout the year (Figure1). Accidental LBP does not tend to occur frequently in winter season. The onset of accidental LBP by day occurs most on Mondays (20.3%) followed by Tuesdays (16.6%) (Figure 2), therefore, accidental LBP tends to occur frequently at the beginning of the week. Also, the onset rates of accidental LBP by time distinction are 11.2%, 16.6% and 14.9% from 8:01 to 9:00, from 9:01 to 10:00 and from 10:01 to 11:00, respectively (Figure 3). The onset of accidental LBP occurs most often in the morning, the rate being 43.1% between 8:00 and 11:00. Moreover, the onset of accidental LBP is more frequent in non-manufacturers (54.7%) than in manufacturers (31.7%). Specifically, traffic and transportation (22.6%), construction (14.5%), and commerce, finance and advertising (10.4%) in the non-manufacturing account for more than 10% of the onset of accidental LBP, on the other hand, mining (13.9) and cargo handling (12.3) account for more than 10 in the number of case per 10,000 of the working population. The accumulated percentage of cases of LBP by duration of employment shows

It is considered that prevention measures for occupational LBP by type of job have many common parts, as the onset of accidental LBP is similar to prevalence of occupational LBP by type of job in other countries. However, as the incidence of occupational LBP in day and time might be different among countries because of life and working style, it is necessary to

take prevention measures in the case of frequent occurrence of occupational LBP.

Fig. 1. Onset of LBP by months (JISHA, 1994)

Fig. 2. Onset of LBP by days (JISHA, 1994)

Fig. 3. Onset of LBP by hours (JISHA, 1994)

Epidemiology 13

These trends of LBP may be caused by the change of the exposure to risk factors and the

Physical factors include heavy physical work, manual material handling, lifting, pushing and pulling, frequent bending and twisting, awkward posture, repetitive work, and wholebody vibration (WBV). The one of the causes of LBP by physical factors is the load to disc and back muscles. Disc pressure and muscle activities are changed by posture and way a load is lifted. Fig. 5 and 6 are the figures indicating the change in disc pressure by posture

Fig. 5. Relative change in pressure (or load) in the third lumber disc in various positions in

Fig. 6. Relative change in pressure (or load) in the third lumber disc in various muscle-

strengthening exercise in living subjects (Nachemson, 1976)

difference of work by gender.

and exercise (Nachemson, 1976).

living subjects (Nachemson, 1976)

**2.3.1 Physical factors** 

#### **2.3 Risk factors of occupational LBP**

Work-related risk factors in LBP are complex. Physical, psychosocial and personal factors interact in various ways to cause occupational LBP, although the degree of associated with the onset of occupational LBP is different. Namely, these factors have an effect on the incidence of occupational LBP and there is association among these factors (Fig. 4). The influence of these risk factors on LBP are reported, but the results are various.

Fig. 4. The relationship of incidence of LBP with physical, psychological and personal factors

Burdorf and Sorock investigated the positive and negative evidence of risk factors for back disorders (Burdorf & Sorock, 1997). They selected 35 studies and estimated the risk of back disorders. Risk estimates of manual material handling, frequent bending and twisting, heavy physical load, static work posture, repetitive movements, and whole-body vibrations for positive associations in physical risk factors at work ranged from 1.12 to 3.07, from 1.29 to 8.09, from 1.54 to 3.71, from 1.30 to 3.29, 1.97, and from 1.47 to 9.00, respectively, and risk estimates of mental stress, job dissatisfaction, work pace, and monotonous work for positive associations in psychological risk factors at work ranged from 1.30 to 2.08, from 1.39 to 2.40, 1.21, and from 1.25 to 2.34, respectively (Burdorf & Sorock, 1997). Thorbjornsson et al., investigated the psychosocial and physical risk factors associated with LBP for over 24 years from 1969 to 1993 (Thorbjornsson et al., 1998). In this study, the prevalence of LBP was 24% among men and 34% among women in 1969, and the cumulative incidence of LBP from 1970 to 1992 were 43% and 38% among men and women, respectively. The prevalence of LBP over the past 12 months in 1993 was 39% among men and 44% among women (Thorbjornsson et al., 1998). Moreover, the highest associations between work related factors and LBP (prevalence ratio adjusted for age) was high physical load (1.4) among men and monotonous work (1.6) among women in 1969, full time work (2.1) among men and high mental load (1.4) among women in 1970-1992, and monotonous work (1.5) among men and poor social support (1.2) among women in 1993, respectively (Thorbjornsson et al., 1998).

Work-related risk factors in LBP are complex. Physical, psychosocial and personal factors interact in various ways to cause occupational LBP, although the degree of associated with the onset of occupational LBP is different. Namely, these factors have an effect on the incidence of occupational LBP and there is association among these factors (Fig. 4). The

> Psychosocial factors ・job content ・increasing work ・job control ・social support ・job satisfaction

・feeling stress

・relationship with co-workers

Personal factors ・age ・gender ・anthropometry ・education ・medical history ・physical activity h bit ( ki d i ki )

Fig. 4. The relationship of incidence of LBP with physical, psychological and personal factors

**Low back pain**

Burdorf and Sorock investigated the positive and negative evidence of risk factors for back disorders (Burdorf & Sorock, 1997). They selected 35 studies and estimated the risk of back disorders. Risk estimates of manual material handling, frequent bending and twisting, heavy physical load, static work posture, repetitive movements, and whole-body vibrations for positive associations in physical risk factors at work ranged from 1.12 to 3.07, from 1.29 to 8.09, from 1.54 to 3.71, from 1.30 to 3.29, 1.97, and from 1.47 to 9.00, respectively, and risk estimates of mental stress, job dissatisfaction, work pace, and monotonous work for positive associations in psychological risk factors at work ranged from 1.30 to 2.08, from 1.39 to 2.40, 1.21, and from 1.25 to 2.34, respectively (Burdorf & Sorock, 1997). Thorbjornsson et al., investigated the psychosocial and physical risk factors associated with LBP for over 24 years from 1969 to 1993 (Thorbjornsson et al., 1998). In this study, the prevalence of LBP was 24% among men and 34% among women in 1969, and the cumulative incidence of LBP from 1970 to 1992 were 43% and 38% among men and women, respectively. The prevalence of LBP over the past 12 months in 1993 was 39% among men and 44% among women (Thorbjornsson et al., 1998). Moreover, the highest associations between work related factors and LBP (prevalence ratio adjusted for age) was high physical load (1.4) among men and monotonous work (1.6) among women in 1969, full time work (2.1) among men and high mental load (1.4) among women in 1970-1992, and monotonous work (1.5) among men and poor social support (1.2) among women in 1993, respectively (Thorbjornsson et al., 1998).

influence of these risk factors on LBP are reported, but the results are various.

**2.3 Risk factors of occupational LBP** 

Physical factors ・heavy physical work ・manual material handling

・pushing and pulling ・frequent bending and twisting

・awkward posture ・repetitive work ・whole-body vibration

・lifting

These trends of LBP may be caused by the change of the exposure to risk factors and the difference of work by gender.

#### **2.3.1 Physical factors**

Physical factors include heavy physical work, manual material handling, lifting, pushing and pulling, frequent bending and twisting, awkward posture, repetitive work, and wholebody vibration (WBV). The one of the causes of LBP by physical factors is the load to disc and back muscles. Disc pressure and muscle activities are changed by posture and way a load is lifted. Fig. 5 and 6 are the figures indicating the change in disc pressure by posture and exercise (Nachemson, 1976).

Fig. 5. Relative change in pressure (or load) in the third lumber disc in various positions in living subjects (Nachemson, 1976)

Fig. 6. Relative change in pressure (or load) in the third lumber disc in various musclestrengthening exercise in living subjects (Nachemson, 1976)

Epidemiology 15

classified as weak, 30 (28%) were classified as moderate, 38 (36%) were classified as strong and6 (5%) were classified as protective. There was noticeable difference in the proportion of estimates considered statistically significant in high-quality (18%) compared with lowquality studies (79%). They concluded that there was some moderate evidence for the association for specific types of lifting and LBP, and some evidence for the association between lifting greater than 25-35kg and LBP (Wai et al., 2010b). Twenty-two studies (27,785 participants, 10 countries) that reported a total of 109 separate risk estimates of the association between specific categories of occupational carrying and specific type of LBP outcomes were enrolled. The mean prevalence of LBP was 33.6%. Twenty-six (24%) were reported to be statistically significant, and of these 26, 15 (58%) were classified as weak, 8 (31%) were classified as moderate and 3 (12%) were classified as strong. There was the marked difference in the proportion of estimates considered statistically significant for highquality (2%) compared with low-quality studies (35%). They concluded that there was strong and consistent evidence against both an association and temporal relationship between carrying and LBP, and there was no independent causal relationship between

Bending is defined as flexion of the trunk, usually in the forward or lateral direction. Twisting refers to trunk rotation or torsion. Awkward postures include non-neutral trunk postures (related to bending and twisting) in extreme positions or at extreme angles (Bernard et al., 1997a). Bernard et al. selected 12 studies and investigated the relationship between back disorders and bending, twisting and awkward postures. The evidence of association with low-back disorders and awkward postures was shown (Bernard et al., 1997a). Results were consistent in showing increased risk of back disorder with exposure, despite the fact that studies defined disorders and assessed exposures in many ways. OR in the studies that indicated statistical significance showed the range of 1.2 to 8.1 (Bernard et al., 1997a). In a systematic review of the association of occupational bending or twisting and LBP by Wai et al., 35 studies (44,342 participants, 15 countries) that reported a total of 243 estimates of the association between specific categories of bending or twisting and specific types of LBP outcomes were enrolled. The mean prevalence of LBP was 38.7%. 107 (44%) were reported as statistically significant, and of these 107 statistically significant estimates of association, 61 (57%) were classified as weak, 20 (19%) were classified as moderate and 26 (24%) were classified as strong. No difference was noted in the proportion of estimates considered as statistically significant for high-quality (30%) versus low-quality studies (32%). They concluded that occupational bending or twisting is unlikely to be independently causative of LBP in workers and the strength of association was often rated as weak or moderate, additionally none demonstrated a statistically significant dose response (Wai et

Static work postures include isometric positions where very little movement occurs, along with cramped or inactive postures that cause static loading on the muscles. These included prolonged standing or sitting and sedentary work. In many cases, the exposure was defined subjectively and/or in combination with other work-related risk factors (Bernard et al., 1997a). Bernard et al. selected 10 studies and resulted that the evidence of association with back disorders and static postures was inadequate though it is not easy to estimate the strength of association for some reasons (Bernard et al., 1997a). OR and RR showed in the studies that indicated statistical significance the range of 1.3 to 24.6 and 1.7 to 2.4,

carrying and LBP (Wai et al., 2010c).

al., 2010a).

Heavy physical work has been defined as work that has high energy demands or requires some measure of physical strength (Bernard et al., 1997a). The investigation of Bernard et al. provided evidence that low-back disorders are associated with heavy physical work (Bernard et al., 1997a). They selected 18 studies, and odds ratio (OR) and relative risk (RR) in the studies that indicated statistical significance showed the range of 1.2 to 12.1 and 2.2 to 4.3, respectively (Bernard et al., 1997a). Roffey et al. undertook a systematic review of the association of occupational pushing or pulling and workplace manual handling or patient assisting, and LBP (Roffey et al., 2010d, 2010e). Thirteen studies (12,793 participants, 7 countries) that reported a total of 83 estimates of the association between specific categories of occupational pushing or pulling and specific types of LBP outcomes enrolled. The mean prevalence of LBP was 38.1%. Sixteen (19%) were found to be statistically significant and 10 (52%) of which were classified as weak, 4 (24%) were classified as moderate, and 2 (10%) were classified as protective. An equal number of statistically significant estimates were reported in high-quality (50%) versus low-quality studies (50%). They concluded that occupational pushing or pulling does not appear to be independently causative of LBP in workers. There was conflicting evidence for association, though 4 out of 6 high-quality studies did not show any association and only one study with statistically significant weak association indicated a dose-response trend (Roffey et al., 2010d). Additionally, 32 studies (22,143 participants, 16 countries) that reported a total of 329 estimates of the association between specific categories of workplace manual handling or assisting patients, and specific types of LBP outcomes were enrolled (Roffey et al., 2010e). The mean prevalence of LBP was 39.2%. 72 (22%) were reported as statistically significant and of these 72 were statistically significant estimates of association, 49 (68%) were classified as weak, 17 (24%) were classified as moderate, 4 (5%) were classified as strong and 2 (3%) were classified as protective. A difference was noted in the proportion of estimates considered statistically significant from high-quality (38%) versus low-quality studies (62%). They concluded that specific categories of patient assisting could contribute to LBP because of the presence of a combination of strong and conflicting evidence, and assisting patients to ambulate could possibly be associated with disabling types of LBP in the nursing occupation (Roffey et al., 2010e).

Lifting is defined as moving or bringing something from a lower level to a higher one. The concept encompasses stresses resulting from work done in transferring objects from one plane to another, as well as the efforts of varying techniques of patient handling and transfer (Bernard et al., 1997a). Manual materials handling includes lifting, moving, carrying and holding loads. Forceful movements include movement of objects in other ways, such as pulling, pushing, or other efforts (Bernard et al., 1997a). Bernard et al. examined the relationship between back disorders and lifting or forceful movement in 18 studies, and there is strong evidence that low-back disorders are associated with work-related lifting or forceful movement (Bernard et al., 1997a). OR and RR in the studies that indicated statistical significance showed the range of 1.3 to 10.7 and 1.2 to 4.5, respectively (Bernard et al., 1997a). Wai et al. carried out a systematic review of the association of occupational lifting and carrying, and LBP (Wai et al., 2010b, 2010c). Thirty-five studies (88,864 participants, 16 countries) that assessed lifting reported a total of 224 separate estimates of the association between specific categories of occupational lifting and specific type of LBP outcomes were enrolled. The mean prevalence of LBP was 37.2%. 107 (48%) were reported to be statistically significant, and of these 107 statistically significant estimates of association, 33 (31%) were

Heavy physical work has been defined as work that has high energy demands or requires some measure of physical strength (Bernard et al., 1997a). The investigation of Bernard et al. provided evidence that low-back disorders are associated with heavy physical work (Bernard et al., 1997a). They selected 18 studies, and odds ratio (OR) and relative risk (RR) in the studies that indicated statistical significance showed the range of 1.2 to 12.1 and 2.2 to 4.3, respectively (Bernard et al., 1997a). Roffey et al. undertook a systematic review of the association of occupational pushing or pulling and workplace manual handling or patient assisting, and LBP (Roffey et al., 2010d, 2010e). Thirteen studies (12,793 participants, 7 countries) that reported a total of 83 estimates of the association between specific categories of occupational pushing or pulling and specific types of LBP outcomes enrolled. The mean prevalence of LBP was 38.1%. Sixteen (19%) were found to be statistically significant and 10 (52%) of which were classified as weak, 4 (24%) were classified as moderate, and 2 (10%) were classified as protective. An equal number of statistically significant estimates were reported in high-quality (50%) versus low-quality studies (50%). They concluded that occupational pushing or pulling does not appear to be independently causative of LBP in workers. There was conflicting evidence for association, though 4 out of 6 high-quality studies did not show any association and only one study with statistically significant weak association indicated a dose-response trend (Roffey et al., 2010d). Additionally, 32 studies (22,143 participants, 16 countries) that reported a total of 329 estimates of the association between specific categories of workplace manual handling or assisting patients, and specific types of LBP outcomes were enrolled (Roffey et al., 2010e). The mean prevalence of LBP was 39.2%. 72 (22%) were reported as statistically significant and of these 72 were statistically significant estimates of association, 49 (68%) were classified as weak, 17 (24%) were classified as moderate, 4 (5%) were classified as strong and 2 (3%) were classified as protective. A difference was noted in the proportion of estimates considered statistically significant from high-quality (38%) versus low-quality studies (62%). They concluded that specific categories of patient assisting could contribute to LBP because of the presence of a combination of strong and conflicting evidence, and assisting patients to ambulate could possibly be associated with disabling types of LBP in the nursing occupation (Roffey et al.,

Lifting is defined as moving or bringing something from a lower level to a higher one. The concept encompasses stresses resulting from work done in transferring objects from one plane to another, as well as the efforts of varying techniques of patient handling and transfer (Bernard et al., 1997a). Manual materials handling includes lifting, moving, carrying and holding loads. Forceful movements include movement of objects in other ways, such as pulling, pushing, or other efforts (Bernard et al., 1997a). Bernard et al. examined the relationship between back disorders and lifting or forceful movement in 18 studies, and there is strong evidence that low-back disorders are associated with work-related lifting or forceful movement (Bernard et al., 1997a). OR and RR in the studies that indicated statistical significance showed the range of 1.3 to 10.7 and 1.2 to 4.5, respectively (Bernard et al., 1997a). Wai et al. carried out a systematic review of the association of occupational lifting and carrying, and LBP (Wai et al., 2010b, 2010c). Thirty-five studies (88,864 participants, 16 countries) that assessed lifting reported a total of 224 separate estimates of the association between specific categories of occupational lifting and specific type of LBP outcomes were enrolled. The mean prevalence of LBP was 37.2%. 107 (48%) were reported to be statistically significant, and of these 107 statistically significant estimates of association, 33 (31%) were

2010e).

classified as weak, 30 (28%) were classified as moderate, 38 (36%) were classified as strong and6 (5%) were classified as protective. There was noticeable difference in the proportion of estimates considered statistically significant in high-quality (18%) compared with lowquality studies (79%). They concluded that there was some moderate evidence for the association for specific types of lifting and LBP, and some evidence for the association between lifting greater than 25-35kg and LBP (Wai et al., 2010b). Twenty-two studies (27,785 participants, 10 countries) that reported a total of 109 separate risk estimates of the association between specific categories of occupational carrying and specific type of LBP outcomes were enrolled. The mean prevalence of LBP was 33.6%. Twenty-six (24%) were reported to be statistically significant, and of these 26, 15 (58%) were classified as weak, 8 (31%) were classified as moderate and 3 (12%) were classified as strong. There was the marked difference in the proportion of estimates considered statistically significant for highquality (2%) compared with low-quality studies (35%). They concluded that there was strong and consistent evidence against both an association and temporal relationship between carrying and LBP, and there was no independent causal relationship between carrying and LBP (Wai et al., 2010c).

Bending is defined as flexion of the trunk, usually in the forward or lateral direction. Twisting refers to trunk rotation or torsion. Awkward postures include non-neutral trunk postures (related to bending and twisting) in extreme positions or at extreme angles (Bernard et al., 1997a). Bernard et al. selected 12 studies and investigated the relationship between back disorders and bending, twisting and awkward postures. The evidence of association with low-back disorders and awkward postures was shown (Bernard et al., 1997a). Results were consistent in showing increased risk of back disorder with exposure, despite the fact that studies defined disorders and assessed exposures in many ways. OR in the studies that indicated statistical significance showed the range of 1.2 to 8.1 (Bernard et al., 1997a). In a systematic review of the association of occupational bending or twisting and LBP by Wai et al., 35 studies (44,342 participants, 15 countries) that reported a total of 243 estimates of the association between specific categories of bending or twisting and specific types of LBP outcomes were enrolled. The mean prevalence of LBP was 38.7%. 107 (44%) were reported as statistically significant, and of these 107 statistically significant estimates of association, 61 (57%) were classified as weak, 20 (19%) were classified as moderate and 26 (24%) were classified as strong. No difference was noted in the proportion of estimates considered as statistically significant for high-quality (30%) versus low-quality studies (32%). They concluded that occupational bending or twisting is unlikely to be independently causative of LBP in workers and the strength of association was often rated as weak or moderate, additionally none demonstrated a statistically significant dose response (Wai et al., 2010a).

Static work postures include isometric positions where very little movement occurs, along with cramped or inactive postures that cause static loading on the muscles. These included prolonged standing or sitting and sedentary work. In many cases, the exposure was defined subjectively and/or in combination with other work-related risk factors (Bernard et al., 1997a). Bernard et al. selected 10 studies and resulted that the evidence of association with back disorders and static postures was inadequate though it is not easy to estimate the strength of association for some reasons (Bernard et al., 1997a). OR and RR showed in the studies that indicated statistical significance the range of 1.3 to 24.6 and 1.7 to 2.4,

Epidemiology 17

of having LBP (OR is over 1.7), and the influence of the duration of the exposure seems more important than the magnitude of the exposure in cumulative effect, though sitting by itself

Psychosocial factors are defined as factors influencing health, health services and community well-being stemming from the psychology of the individual and the structure and function of social groups. They include social characteristics such as patterns of interaction within family or occupational groups, cultural characteristics such as traditional ways of solving conflicts, and psychological characteristics such as attitudes, beliefs and personality factors (WHO, 2001). Bongers et al. showed 5 categories of factors that may be

1. psychosocial factors at work - demands and control (monotonous work, time pressure, high concentration, high responsibilities, high work load, few opportunities to take

2. psychosocial factors at work - social support (poor social support from colleagues and

3. individual characteristics (personality type, type A behaviour, extrovert personality, psychological dysfunctioning, coping style, attitude towards own health, low social

4. stress symptoms (worry, tension, anxiety, physical stress symptoms, fatigue or exhaustion, high perceived work stress, low job satisfaction, and physiological

5. physical and behavioural health indicators (poor physician health, respiratory disease or cough, stomach trouble, cardiovascular disease, headache, use of mediation and use

Bernerd et al. investigated the association of psychosocial factors with back disorder (Bernard et al., 1997b). 4 of 5 studies that included measures of intensified work load found significant associations between back disorders and perceptions of intensified work load as measured by indices of both perceived time pressure and work load (OR 1.2-2.9). 5 of 7 studies that assess job dissatisfaction also found positive associations with back disorders. One study examined the relationship between social support and back disorders and found

In a systematic review by Hoogendoorn et al. including 11 cohort and 2 case-control studies, strong evidence was found for low social support in the workplace and low job satisfaction as risk factors for back pain (Hoogendoorn et al., 2000). Also, in the cohort study of 861 workers in Hoogendoorn et al., cumulative incidence of LBP during 3 years follow-up period was 26.6% (Hoogendoorn et al., 2001). The strongest relationships with LBP were found for high quantitative job demands, low supervisory support and low co-worker support (RR 1.3-1.6). However, most of the relationships were not statistically significant. They concluded that low

In a systematic review by Bongers et al. the associations between self-reported work demands (particularly monotonous work), poor social support at work, personality traits and emotional

problems, and stress symptoms, and back trouble were reported (Bongers et al., 1993).

did not increase the association with the present LBP (Lis et al., 2007).

breaks, lack of clarity, and low control and little autonomy),

co-worker and supervisory support appeared to be risk factors of LBP.

**2.3.2 Psychosocial factors** 

associated with musculoskeletal symptoms:

poor social support from superiors),

of medical service), (Bongers et al., 1993).

class and low educational level),

only weak evidence for an association.

parameters), and

respectively (Bernard et al., 1997a). Roffey et al. carried out a systematic review of the association of 3 factors, awkward occupational postures, occupational sitting, and occupational standing or walking, and LBP (Roffey et al., 2010a, 2010b, 2010c). Twenty seven studies (69,980 participants, 14 countries) that reported a total of 111 estimates of the association between specific categories of awkward occupational postures and specific types of LBP outcomes were enrolled. The mean prevalence of LBP was 47.8%. Fifty-three (48%) were reported as statistically significant, and of these 53 statistically significant estimates of association, 35 (66%) were classified as weak, 9 (17%) were classified as moderate, 4 (7%) were classified as strong and 3 (6%) were classified as protective. There was a difference noted in the proportion of estimates considered statistically significant for high-quality (35%) versus low-quality studies (57%). They concluded that awkward occupational postures do not appear to be independently causative of LBP in workers, and the strength of association was rated as weak, and only one study demonstrated a trend toward a nonstatistically significant dose response. They added that awkward postures could have an association with severe types of LBP in certain working populations, but causal relationship with LBP seems unlikely because of the conflicting or lack of strong evidence identified for the association from their results (Roffey et al., 2010a). Twenty-four studies (75,103 participants, 12 countries) that reported a total of 108 separate estimates of the association between specific categories of occupational sitting and specific types of LBP outcomes were enrolled. The mean prevalence of LBP was 42.2%. Seventeen (16%) were reported to be statistically significant and of these 17 statistically significant estimates, 3 (18%) were classified as weak and 14 (82%) were classified as protective. There was a marked difference in the proportion of estimates considered statistically significant for high-quality (0%) versus low-quality studies (100%). They concluded that occupational sitting does not appear to be independently causative of LBP in workers and the strength of evidence suggesting no association was consistent and rated as strong, with only one study demonstrating a trend toward a nonstatistically significant dose response (Roffey et al., 2010b). Eighteen studies (31,810 participants, 10 countries) that reported a total of 84 estimates of the association between specific categories of occupational standing or walking and specific types of LBP outcomes were enrolled. The mean prevalence of LBP was 43.2%. 21 (25%) were reported to be statistically significant and of these 21 statistically significant estimates, 11 (52%) were classified as weak, 5 (24%) were classified as moderate and 2 (10%) were classified as protective. A difference was noted between the numbers of statistically significant estimates that came from high-quality (19%) versus low-quality studies (81%). They concluded that occupational standing or walking is unlikely to be independently causative of LBP in workers, but if a causal relationship between occupational standing and LBP were to exist, it would likely to be a very weak one and only likely in specific sub categories (Roffey et al., 2010c).

WBV refers to mechanical energy oscillations which are transferred to the body as a whole (in contrast to specific body regions), usually through a supporting system such as a seat or platform. Typical exposures include driving automobiles and trucks, and operating industrial vehicles (Bernard et al., 1997a). Nineteen studies were selected and there is strong evidence of the positive association between exposure to WBV and back disorder though 4 of 19 studies demonstrated no association. OR and RR in the studies that indicated statistical significance showed the range of 1.2 to 39.5 and 1.7, respectively (Bernard et al., 1997). Lis et al. reported that occupational groups exposed to WBV while sitting are at an increased risk

respectively (Bernard et al., 1997a). Roffey et al. carried out a systematic review of the association of 3 factors, awkward occupational postures, occupational sitting, and occupational standing or walking, and LBP (Roffey et al., 2010a, 2010b, 2010c). Twenty seven studies (69,980 participants, 14 countries) that reported a total of 111 estimates of the association between specific categories of awkward occupational postures and specific types of LBP outcomes were enrolled. The mean prevalence of LBP was 47.8%. Fifty-three (48%) were reported as statistically significant, and of these 53 statistically significant estimates of association, 35 (66%) were classified as weak, 9 (17%) were classified as moderate, 4 (7%) were classified as strong and 3 (6%) were classified as protective. There was a difference noted in the proportion of estimates considered statistically significant for high-quality (35%) versus low-quality studies (57%). They concluded that awkward occupational postures do not appear to be independently causative of LBP in workers, and the strength of association was rated as weak, and only one study demonstrated a trend toward a nonstatistically significant dose response. They added that awkward postures could have an association with severe types of LBP in certain working populations, but causal relationship with LBP seems unlikely because of the conflicting or lack of strong evidence identified for the association from their results (Roffey et al., 2010a). Twenty-four studies (75,103 participants, 12 countries) that reported a total of 108 separate estimates of the association between specific categories of occupational sitting and specific types of LBP outcomes were enrolled. The mean prevalence of LBP was 42.2%. Seventeen (16%) were reported to be statistically significant and of these 17 statistically significant estimates, 3 (18%) were classified as weak and 14 (82%) were classified as protective. There was a marked difference in the proportion of estimates considered statistically significant for high-quality (0%) versus low-quality studies (100%). They concluded that occupational sitting does not appear to be independently causative of LBP in workers and the strength of evidence suggesting no association was consistent and rated as strong, with only one study demonstrating a trend toward a nonstatistically significant dose response (Roffey et al., 2010b). Eighteen studies (31,810 participants, 10 countries) that reported a total of 84 estimates of the association between specific categories of occupational standing or walking and specific types of LBP outcomes were enrolled. The mean prevalence of LBP was 43.2%. 21 (25%) were reported to be statistically significant and of these 21 statistically significant estimates, 11 (52%) were classified as weak, 5 (24%) were classified as moderate and 2 (10%) were classified as protective. A difference was noted between the numbers of statistically significant estimates that came from high-quality (19%) versus low-quality studies (81%). They concluded that occupational standing or walking is unlikely to be independently causative of LBP in workers, but if a causal relationship between occupational standing and LBP were to exist, it would likely to be a very weak one and only likely in specific sub categories (Roffey et al.,

WBV refers to mechanical energy oscillations which are transferred to the body as a whole (in contrast to specific body regions), usually through a supporting system such as a seat or platform. Typical exposures include driving automobiles and trucks, and operating industrial vehicles (Bernard et al., 1997a). Nineteen studies were selected and there is strong evidence of the positive association between exposure to WBV and back disorder though 4 of 19 studies demonstrated no association. OR and RR in the studies that indicated statistical significance showed the range of 1.2 to 39.5 and 1.7, respectively (Bernard et al., 1997). Lis et al. reported that occupational groups exposed to WBV while sitting are at an increased risk

2010c).

of having LBP (OR is over 1.7), and the influence of the duration of the exposure seems more important than the magnitude of the exposure in cumulative effect, though sitting by itself did not increase the association with the present LBP (Lis et al., 2007).

#### **2.3.2 Psychosocial factors**

Psychosocial factors are defined as factors influencing health, health services and community well-being stemming from the psychology of the individual and the structure and function of social groups. They include social characteristics such as patterns of interaction within family or occupational groups, cultural characteristics such as traditional ways of solving conflicts, and psychological characteristics such as attitudes, beliefs and personality factors (WHO, 2001). Bongers et al. showed 5 categories of factors that may be associated with musculoskeletal symptoms:


Bernerd et al. investigated the association of psychosocial factors with back disorder (Bernard et al., 1997b). 4 of 5 studies that included measures of intensified work load found significant associations between back disorders and perceptions of intensified work load as measured by indices of both perceived time pressure and work load (OR 1.2-2.9). 5 of 7 studies that assess job dissatisfaction also found positive associations with back disorders. One study examined the relationship between social support and back disorders and found only weak evidence for an association.

In a systematic review by Hoogendoorn et al. including 11 cohort and 2 case-control studies, strong evidence was found for low social support in the workplace and low job satisfaction as risk factors for back pain (Hoogendoorn et al., 2000). Also, in the cohort study of 861 workers in Hoogendoorn et al., cumulative incidence of LBP during 3 years follow-up period was 26.6% (Hoogendoorn et al., 2001). The strongest relationships with LBP were found for high quantitative job demands, low supervisory support and low co-worker support (RR 1.3-1.6). However, most of the relationships were not statistically significant. They concluded that low co-worker and supervisory support appeared to be risk factors of LBP.

In a systematic review by Bongers et al. the associations between self-reported work demands (particularly monotonous work), poor social support at work, personality traits and emotional problems, and stress symptoms, and back trouble were reported (Bongers et al., 1993).

Epidemiology 19

spine mobility or muscle strength seems to have poor association with the incidence of LBP, as it is considered that these losses are secondary (Andersson, 1992). Hamberg-van Reenen et al. in systematic review found that strong evidence that there was no relationship between trunk muscle endurance and the risk of LBP. Moreover, inconclusive evidence for a relationship between trunk muscle strength or mobility of lumbar spine and the risk of LBP was found (Hamberg-van Reenen et al., 2007). There is the report that sagittal spine mobility, static spinal posture, muscle endurance and spinal repositioning error show no difference between subjects with LBP and without LBP (Mitchell et al., 2009). Conflicting evidence is found for the association between physical activity and LBP in the general population and in school children in 10 high-quality studies (Sitthipornvorakul, 2011). They reported high level physical activity at leisure time related to decreased prevalence of LBP and high level physical activity at work combined with low physical activity in leisure time associated with high prevalence of LBP. Also, Heneweer et al. in systematic review reported that there was strong evidence that intense physical exertion during leisure time (regular home improvement activities and high perceived load in, and regular and high intensity sports, and physical exercise in the upper percentile) was moderately (1.0-2.6) associated with LBP, and everyday physical activities in leisure time and the performance of gardening/yard work were found to be strongly (0.20-0.76) to moderately (0.38-0.80) associated with

In the relationship between socioeconomic status and LBP, most studies concluded education is strongly associated with LBP, with a high prevalence and risk of LBP for those with low educational level (Astrand, 1987; Latza et al., 2004; Leclerc et al., 2009; Leino-Arjas et al., 1998). In addition, it is reported that prevalence and risk of LBP is high for those with low-income occupational status and manual workers. Latza et al. also reported that severe current back pain was related to educational level and health insurance status, and members of sick funds for white-collar workers (OR 2.81) and private insurance (OR 2.81) and individuals with intermediate educational level (OR 1.76) utilized more physical therapy for the treatment of back pain (Latza et al., 2004). Severe LBP was less prevalent among adults

It is reported that LBP is associated with smoking in lifestyle factors, though the risk of LBP is depended on smoking history (OR 1.15-1.46 in men), (Leino-Arjas et al., 1998). Smoking is positively associated with both prevalent and future LBP (OR 1.38-6.38), (Hestbaek, 2006). Leboeuf-Yde et al. reported that there was a significant positive association between smoking and LBP that increased with the duration and frequency of the LBP problem, but this association was not appeared in monozygotic twins (Leboeuf-Yde et al., 1998). Leboeuf-Yde also concluded that smoking should be considered a weak risk indicator and not a

Both workers and managers should make efforts to prevent occupational LBP. Improvement of work conditions and the working environment leads to workers' understanding of

occupational health issues. The three main preventive approaches as concepts are:

3. Teaching the worker to use the correct work method (Andersson, 1991).

decreased risk for LBP (Heneweer, 2011).

of higher socioeconomic status (Latza et al., 2000).

cause of LBP (Leboeuf-Yde, 1999).

**2.4 Prevention of occupational LBP** 

1. Designing the job to fit the worker,

2. Selecting the appropriate worker for the job, and

It is considered that low job satisfaction and low social support are associated with LBP, but it is unclear as to the associations between psychosocial factors and LBP. Davis and Heaney hypothesized as to the mechanisms of the relationship between psychosocial factors and LBP. First, psychosocial factors are directly related to LBP by influencing the loading on the spine via changes in trunk kinetics, the forces exerted or muscle activity. Second, psychosocial factors influence various chemical reactions in the body that take place during the performance of job tasks. Third, psychosocial factors influence the reporting of an injury by altering tolerance to pain (Davis & Heaney, 2000). They concluded that job satisfaction and job stress (workers reaction to psychosocial work characteristics) are more consistently and more strongly associated with LBP than are psychosocial work characteristics themselves and stated that not only the relationship between job satisfaction and LBP, but also the relationship between physical and psychosocial work characteristics and job satisfaction are needed to investigate in research (Davis & Heaney, 2000).

#### **2.3.3 Personal factors**

The common personal factors are age, gender, anthropometry, posture, muscle strength, muscle imbalances, spine mobility, education, medical history, physical fitness, habit (e.g. smoking) and socioeconomic conditions.

Most people experienced their first episode of back pain before 35yeras (Guo et al., 1995). In a European study, a prevalence of 18% was found before 25 years and 24% at 55 years and older (Parent-Thirion et al., 2007). The prevalence is relatively consistent during their working years (Guo et al., 1995). Generally, age and years of work are correlated, as the length of duration of work increases with advancing age. Moreover, the longer the years of work the greater the occupational exposure, additionally the likelihood of disc degeneration and herniation increases with aging. In a systematic review by Burdorf and Sorock, 12 studies reported positive association between age and back disorders, and 15 studies demonstrated no associations out of 30 studies (Burdorf & Sorock, 1997). Though pregnancy (Mogren, 2005) and osteoporotic fractures (Rostom, 2011) which are characteristic of women are causes of LBP, these are not work-related factors. Of course, LBP caused by these factors could possibly lead to leaving work and absence. The prevalence of back pain is equal among men (27%) and women (22%), (Parent-Thirion, 2007), though it is reported that prevalence of LBP is higher in girls than in boys at school age (Jones & Macfarlane, 2009; Mohseni-Bandpei et al., 2007; Watson et al., 2002; Yao et al., 2011). The attributable proportion of occupational LBP was higher for men than women (Punnett, 2005), and the results are very widespread. Occurrence of LBP by gender is considered to be related to differing participation in the various occupations.

It is reported that associations between anthropometry (sitting and standing height, weight, body mass index, trunk asymmetry or kyphosis) and LBP are null or a weak association in children (Kaspiris, 2010; Nissinen, 1994; Poussa, 2005). In adults, Pope et al. reported no associations between anthropometry and LBP (Pope, 1984). However, a weak association is shown between body weight and LBP (Leboeuf-Yde, 2000), and obesity (high body mass index) associated with LBP (Heuch, 2010).

Spine mobility, muscle strength and posture are included in the examination for LBP. Reduction of spine mobility and muscle strength, change of posture and activity, and disable walking are seen in most subjects with LPB due to pain in many cases. However,

It is considered that low job satisfaction and low social support are associated with LBP, but it is unclear as to the associations between psychosocial factors and LBP. Davis and Heaney hypothesized as to the mechanisms of the relationship between psychosocial factors and LBP. First, psychosocial factors are directly related to LBP by influencing the loading on the spine via changes in trunk kinetics, the forces exerted or muscle activity. Second, psychosocial factors influence various chemical reactions in the body that take place during the performance of job tasks. Third, psychosocial factors influence the reporting of an injury by altering tolerance to pain (Davis & Heaney, 2000). They concluded that job satisfaction and job stress (workers reaction to psychosocial work characteristics) are more consistently and more strongly associated with LBP than are psychosocial work characteristics themselves and stated that not only the relationship between job satisfaction and LBP, but also the relationship between physical and psychosocial work characteristics and job

The common personal factors are age, gender, anthropometry, posture, muscle strength, muscle imbalances, spine mobility, education, medical history, physical fitness, habit (e.g.

Most people experienced their first episode of back pain before 35yeras (Guo et al., 1995). In a European study, a prevalence of 18% was found before 25 years and 24% at 55 years and older (Parent-Thirion et al., 2007). The prevalence is relatively consistent during their working years (Guo et al., 1995). Generally, age and years of work are correlated, as the length of duration of work increases with advancing age. Moreover, the longer the years of work the greater the occupational exposure, additionally the likelihood of disc degeneration and herniation increases with aging. In a systematic review by Burdorf and Sorock, 12 studies reported positive association between age and back disorders, and 15 studies demonstrated no associations out of 30 studies (Burdorf & Sorock, 1997). Though pregnancy (Mogren, 2005) and osteoporotic fractures (Rostom, 2011) which are characteristic of women are causes of LBP, these are not work-related factors. Of course, LBP caused by these factors could possibly lead to leaving work and absence. The prevalence of back pain is equal among men (27%) and women (22%), (Parent-Thirion, 2007), though it is reported that prevalence of LBP is higher in girls than in boys at school age (Jones & Macfarlane, 2009; Mohseni-Bandpei et al., 2007; Watson et al., 2002; Yao et al., 2011). The attributable proportion of occupational LBP was higher for men than women (Punnett, 2005), and the results are very widespread. Occurrence of LBP by gender is considered to be related to

It is reported that associations between anthropometry (sitting and standing height, weight, body mass index, trunk asymmetry or kyphosis) and LBP are null or a weak association in children (Kaspiris, 2010; Nissinen, 1994; Poussa, 2005). In adults, Pope et al. reported no associations between anthropometry and LBP (Pope, 1984). However, a weak association is shown between body weight and LBP (Leboeuf-Yde, 2000), and obesity (high body mass

Spine mobility, muscle strength and posture are included in the examination for LBP. Reduction of spine mobility and muscle strength, change of posture and activity, and disable walking are seen in most subjects with LPB due to pain in many cases. However,

satisfaction are needed to investigate in research (Davis & Heaney, 2000).

**2.3.3 Personal factors** 

smoking) and socioeconomic conditions.

differing participation in the various occupations.

index) associated with LBP (Heuch, 2010).

spine mobility or muscle strength seems to have poor association with the incidence of LBP, as it is considered that these losses are secondary (Andersson, 1992). Hamberg-van Reenen et al. in systematic review found that strong evidence that there was no relationship between trunk muscle endurance and the risk of LBP. Moreover, inconclusive evidence for a relationship between trunk muscle strength or mobility of lumbar spine and the risk of LBP was found (Hamberg-van Reenen et al., 2007). There is the report that sagittal spine mobility, static spinal posture, muscle endurance and spinal repositioning error show no difference between subjects with LBP and without LBP (Mitchell et al., 2009). Conflicting evidence is found for the association between physical activity and LBP in the general population and in school children in 10 high-quality studies (Sitthipornvorakul, 2011). They reported high level physical activity at leisure time related to decreased prevalence of LBP and high level physical activity at work combined with low physical activity in leisure time associated with high prevalence of LBP. Also, Heneweer et al. in systematic review reported that there was strong evidence that intense physical exertion during leisure time (regular home improvement activities and high perceived load in, and regular and high intensity sports, and physical exercise in the upper percentile) was moderately (1.0-2.6) associated with LBP, and everyday physical activities in leisure time and the performance of gardening/yard work were found to be strongly (0.20-0.76) to moderately (0.38-0.80) associated with decreased risk for LBP (Heneweer, 2011).

In the relationship between socioeconomic status and LBP, most studies concluded education is strongly associated with LBP, with a high prevalence and risk of LBP for those with low educational level (Astrand, 1987; Latza et al., 2004; Leclerc et al., 2009; Leino-Arjas et al., 1998). In addition, it is reported that prevalence and risk of LBP is high for those with low-income occupational status and manual workers. Latza et al. also reported that severe current back pain was related to educational level and health insurance status, and members of sick funds for white-collar workers (OR 2.81) and private insurance (OR 2.81) and individuals with intermediate educational level (OR 1.76) utilized more physical therapy for the treatment of back pain (Latza et al., 2004). Severe LBP was less prevalent among adults of higher socioeconomic status (Latza et al., 2000).

It is reported that LBP is associated with smoking in lifestyle factors, though the risk of LBP is depended on smoking history (OR 1.15-1.46 in men), (Leino-Arjas et al., 1998). Smoking is positively associated with both prevalent and future LBP (OR 1.38-6.38), (Hestbaek, 2006). Leboeuf-Yde et al. reported that there was a significant positive association between smoking and LBP that increased with the duration and frequency of the LBP problem, but this association was not appeared in monozygotic twins (Leboeuf-Yde et al., 1998). Leboeuf-Yde also concluded that smoking should be considered a weak risk indicator and not a cause of LBP (Leboeuf-Yde, 1999).

#### **2.4 Prevention of occupational LBP**

Both workers and managers should make efforts to prevent occupational LBP. Improvement of work conditions and the working environment leads to workers' understanding of occupational health issues. The three main preventive approaches as concepts are:


Epidemiology 21

these guidelines (Waddell & Burrton, 2001). In prevention, there were 3 strong pieces of evidences (provided by generally consistent findings in multiple, high quality studies), 2 limited or contradictory findings (provided by one scientific study or inconsistent findings in multiple scientific studies) and 1 finding with no scientific evidence (based on clinical studies, theoretical consideration and/or clinical consensus) (Carter & Brirrell, 2000;

Traditional biomechanical education based on an injury model does not reduce future

 Low job satisfaction and unsatisfactory psychosocial aspects of work are risk factors for reported LBP, health care use and work loss, but the size of that association is modest.

Various general exercise/physical fitness programmes may reduce future LBP and work

 Joint employer-worker initiatives can reduce the number of reported back injuries and sickness absences, but there is no clear evidence on the optimum strategies and

Educational interventions which specifically address beliefs and attitudes may reduce

Table 3. Evidences of prevention of LBP (Carter & Brirrell, 2000; Waddell & Burrton, 2001)

Personal preventions of LBP include an exercise programme for improvement of muscle strength, muscle flexibility, muscle balance and spinal movement, back belts and education before onset LBP. Additionally, rest, traction, joint mobilization, acupuncture, physical therapy, hydrotherapy, electrical therapy and behavioural treatment can be used. European guidelines for the prevention of LBP indicate the interventions for prevention of LBP and evaluate the interventions at the evidence level A to D (The COST B13 Working Group, 2004b). The strength of recommendations is based on the 4-level rating: Level A is generally consistent findings provided by (a systematic review of) multiple RCTs, Level B is generally consistent findings provided by (a systematic review of) multiple weaker scientific studies, Level C is one RCT/weaker scientific study or inconsistent findings provided by (a systematic review of) multiple weaker scientific studies and Level D is no RCTs or no weaker scientific studies. The guidelines focus on providing a set of evidencebased recommendations to prevent LBP and/or its consequences in the workforce. Interventions aim at preventing LBP in the workforce can be categorized into 1) individual focus, 2) physical ergonomics, and 3) organizational ergonomics.

It is difficult to prevent LBP because there are many factors that contribute to LBP and preventive effects can be different according to each individual. Therefore, appropriate prevention of LBP needs to be provided against future LBP, recurrence of LBP, chronic LBP,

Lumbar belts or supports do not reduce work-related LBP and work loss.

Waddell & Burrton, 2001), (Table 3).

Limited or contradictory evidence

loss; any effect size appears to be modest.

inconsistent evidence on the effect size.

Strong evidence

LBP and work loss.

No scientific evidence

future work loss due to LBP.

Recommendation shows in Table 4.

worsening LBP and so on.

Moreover, prevention measures are different dependent on the stage of occupational LBP i.e. before and after the occurrence of occupational LBP, and acute, sub-acute or chronic LBP. Classic preventive medicine divides prevention into three categories: primary, secondary and tertiary prevention. Primary prevention of occupational LBP is designed to prevent the onset of LBP by avoiding or decreasing as thoroughly as possible the risk factors that are shown by epidemiological study. Therefore, the health care professional should know what constitutes LBP risk. Occupational factors are more important for disability than for disease or injury, and few individual risk factors hold up to scientific scrutiny. The three main alternatives in primary prevention are a pre-employment screening programme, improvements in work habits and changes at the workplace. Secondary prevention is designed to share knowledge about the risks of, or the problems associated with, LBP, with the added problem of early disease (risk) detection. In tertiary prevention, selection of the appropriate therapy to reduce the disability and chronicity of LBP and to prevent recurrence may be the most immediate and practical prevention method. However, this would be totally redundant if primary prevention could be made effective (Andersson, 1991).

In Japan, the guidelines for prevention of LBP (Ministry of Labour, 1994) concretely show how to exclude causes of LBP and how to promote the maintenance and improvement of workers' conditions:


In addition, the guidelines mention specific measures about 5 types of work (heavy load handling, care work in facilities for severe physically and mentally disabled children, standing work with excessive burden to the back, sitting posture with excessive burden to the back and driving for a long time) where LBP occurs comparatively frequently (Ministry of Labour, 1994). The guidelines demand improvement of working condition and the working environment by the enterprises or employer.

Prevention of occupational LBP is designed to reduce workplace risk at first. This requires the reduction of physical demands by improvement of the workplace (safe working environment such as enough space, arrangement of equipment adapting to workers and temperature), work task (saving of works such as automation, reduction of the weight, shape and size of the load and movement distance), work organization (duration and frequency of loading, rests and supports among workers) and the provision of education and training. The National Institute for Occupational Safety and Health (NIOSH) shows how to improve the workplace (engineering and administrative improvements) in ergonomic guidelines for manual material handling (Cheung et al., 2007). This guideline explains the safety methods for manual material handling in the workplace with pictures.

Carter and Brirrell edited "occupational health guidelines for the management of low back pain at work" (Carter & Brirrell, 2000) and Waddell et al. reported evidence in a review of

Moreover, prevention measures are different dependent on the stage of occupational LBP i.e. before and after the occurrence of occupational LBP, and acute, sub-acute or chronic LBP. Classic preventive medicine divides prevention into three categories: primary, secondary and tertiary prevention. Primary prevention of occupational LBP is designed to prevent the onset of LBP by avoiding or decreasing as thoroughly as possible the risk factors that are shown by epidemiological study. Therefore, the health care professional should know what constitutes LBP risk. Occupational factors are more important for disability than for disease or injury, and few individual risk factors hold up to scientific scrutiny. The three main alternatives in primary prevention are a pre-employment screening programme, improvements in work habits and changes at the workplace. Secondary prevention is designed to share knowledge about the risks of, or the problems associated with, LBP, with the added problem of early disease (risk) detection. In tertiary prevention, selection of the appropriate therapy to reduce the disability and chronicity of LBP and to prevent recurrence may be the most immediate and practical prevention method. However, this would be

totally redundant if primary prevention could be made effective (Andersson, 1991).

movements, c) working standards, d) breaks, and e) others,

work, d) working space, and e) equipment arrangement,

working environment by the enterprises or employer.

workers' conditions:

In Japan, the guidelines for prevention of LBP (Ministry of Labour, 1994) concretely show how to exclude causes of LBP and how to promote the maintenance and improvement of

1. work management: a) automation and saving of labour, b) working postures and

2. work environmental management: a) temperature, b) lighting, c) flooring conditions for

3. health management: a) pre-employment and periodic medical examination, postmeasures, and b) doing exercise before work (warming up) and exercise against LBP,

In addition, the guidelines mention specific measures about 5 types of work (heavy load handling, care work in facilities for severe physically and mentally disabled children, standing work with excessive burden to the back, sitting posture with excessive burden to the back and driving for a long time) where LBP occurs comparatively frequently (Ministry of Labour, 1994). The guidelines demand improvement of working condition and the

Prevention of occupational LBP is designed to reduce workplace risk at first. This requires the reduction of physical demands by improvement of the workplace (safe working environment such as enough space, arrangement of equipment adapting to workers and temperature), work task (saving of works such as automation, reduction of the weight, shape and size of the load and movement distance), work organization (duration and frequency of loading, rests and supports among workers) and the provision of education and training. The National Institute for Occupational Safety and Health (NIOSH) shows how to improve the workplace (engineering and administrative improvements) in ergonomic guidelines for manual material handling (Cheung et al., 2007). This guideline explains the safety methods for manual material handling in the workplace with pictures.

Carter and Brirrell edited "occupational health guidelines for the management of low back pain at work" (Carter & Brirrell, 2000) and Waddell et al. reported evidence in a review of

4. education for occupational health: a) education for occupational health and others.

these guidelines (Waddell & Burrton, 2001). In prevention, there were 3 strong pieces of evidences (provided by generally consistent findings in multiple, high quality studies), 2 limited or contradictory findings (provided by one scientific study or inconsistent findings in multiple scientific studies) and 1 finding with no scientific evidence (based on clinical studies, theoretical consideration and/or clinical consensus) (Carter & Brirrell, 2000; Waddell & Burrton, 2001), (Table 3).

Strong evidence

 Traditional biomechanical education based on an injury model does not reduce future LBP and work loss.

Lumbar belts or supports do not reduce work-related LBP and work loss.

 Low job satisfaction and unsatisfactory psychosocial aspects of work are risk factors for reported LBP, health care use and work loss, but the size of that association is modest.

Limited or contradictory evidence

 Various general exercise/physical fitness programmes may reduce future LBP and work loss; any effect size appears to be modest.

 Joint employer-worker initiatives can reduce the number of reported back injuries and sickness absences, but there is no clear evidence on the optimum strategies and inconsistent evidence on the effect size.

No scientific evidence

 Educational interventions which specifically address beliefs and attitudes may reduce future work loss due to LBP.

Table 3. Evidences of prevention of LBP (Carter & Brirrell, 2000; Waddell & Burrton, 2001)

Personal preventions of LBP include an exercise programme for improvement of muscle strength, muscle flexibility, muscle balance and spinal movement, back belts and education before onset LBP. Additionally, rest, traction, joint mobilization, acupuncture, physical therapy, hydrotherapy, electrical therapy and behavioural treatment can be used. European guidelines for the prevention of LBP indicate the interventions for prevention of LBP and evaluate the interventions at the evidence level A to D (The COST B13 Working Group, 2004b). The strength of recommendations is based on the 4-level rating: Level A is generally consistent findings provided by (a systematic review of) multiple RCTs, Level B is generally consistent findings provided by (a systematic review of) multiple weaker scientific studies, Level C is one RCT/weaker scientific study or inconsistent findings provided by (a systematic review of) multiple weaker scientific studies and Level D is no RCTs or no weaker scientific studies. The guidelines focus on providing a set of evidencebased recommendations to prevent LBP and/or its consequences in the workforce. Interventions aim at preventing LBP in the workforce can be categorized into 1) individual focus, 2) physical ergonomics, and 3) organizational ergonomics. Recommendation shows in Table 4.

It is difficult to prevent LBP because there are many factors that contribute to LBP and preventive effects can be different according to each individual. Therefore, appropriate prevention of LBP needs to be provided against future LBP, recurrence of LBP, chronic LBP, worsening LBP and so on.

Epidemiology 23

episode of LBP Chronic

Fig. 7. Prevention and/or intervention of LBP are needed on the every stage (arrows).

LBP) Recurrence of

Future LBP (Occurrence of

circumstances. These should be applied to all workers.

0-8016-6252-4, St Louis, USA

Nara Medical University, School of Medicine. I thank them deeply.

**4. Acknowledgment** 

**5. References** 

Many people suffer from LBP. It is considered that the lifetime prevalence of LBP ranged from 50% to 80% and about half of the population experienced LBP in a year. As occupational LBP can occur in most workers in various jobs, it is both an individual and social problems. Accidental LBP tends to occur in the morning (8:00-11:00) at the beginning of week. It is considered that there is the evidence that increased risk of LBP is associated with heavy physical work, manual material handling, awkward posture and whole body vibration among physical factors, and job dissatisfaction and low social support among the psychosocial factors and socioeconomic status (low education and occupational status) among the personal factors. These factors interact with the onset of LBP directly or indirectly. Therefore, employers must take measures to reduce the risk factors for LBP by improvement of the workplace, work task and work-organization designs, and education and training. Workers must take measures to prevent LBP similar to those undertaken by employers. There is evidence that physical exercise may be recommended in the prevention of LBP and the prevention of the recurrence of LBP. It is considered that prevention of LBP can be effective if the exercise programme matches the individuals, as there is contradictory evidence and any effect in reducing LBP by various general exercise programmes. We should take suitable measures fitting the stages (i.e. future LBP, present LBP and continuous LBP) to prevent LBP, disability and so on. Needless to say, it is important to make sure of the causes of LBP in the past, present and future. Therefore, health care professionals should understand the risk factors for LBP and fully understand the subjects with LBP and their

LBP

Getting worse of LBP

LBP

I borrowed the books of occupational LBP and musculoskeletal disorders from Professor Kurumatani and Dr. Tomioka in the Department of Community Health and Epidemiology,

Alperovitch-Najenson, D., et al. (2010). Low back pain among professional bus drivers:

Andersson, G.B.J. (1981). Epidemiological aspects on low-back pain in industry: *Spine*, Vol.6,

Andersson, G.B.J. (1991). Concepts in Prevention. In: *Occupational Low Back Pain: Assessment,* 

*Journal*, Vol.12, No.1, (January 2010), pp.26-31, ISSN 1565-1088

No.1, (January-February 1981), pp. 53-60, ISSN 0362-2436

ergonomic and occupational-psychosocial risk factors. *The Israel Medical Association* 

*Treatment and Prevention*, M.H. Pope, et al. (Eds.), 211-216, Mosby Year Book, ISBN

**3. Conclusion** 

Having no

Having a episode of LBP

#### Physical exercise / physical activity

#### Recommendation.

Physical exercise may be recommended in prevention of LBP (Level A). Physical exercise may be recommended in prevention recurrence of LBP (Level A) and in prevention recurrence of sick leave due to LBP (Level C).

#### Information / advice / instruction Recommendation.

Traditional information/advice/instruction on biomechanics, lifting techniques, optimal postures etc is not recommended for prevention in LBP (Level A). there is insufficient evidence to recommended for or against psychosocial information delivered at the worksite (Level C), but information oriented toward promoting activity and improving coping, can promote a positive shift in beliefs (Level C). Whilst the evidence is not sufficiently consistent to recommend education in the prevention of recurrence of sick leave due to LBP (Level C), incorporating the messages from the accompanying clinical guidelines into workplace information/advice is encouraged.

Back belts / lumber supports Recommendation. Back belts/lumber supports are not recommended for prevention in LBP (Level A). Shoe inserts, shoe orthoses, shoe in-soles, flooring and mats Recommendation.

Shoe inserts/shoe orthoses are not recommended for prevention in LBP (Level A). There is insufficient evidence to recommend for or against shoe in-soles, soft shoes, soft flooring or antifatigue floor mats (Level D).

Physical ergonomics

#### Recommendation.

There is insufficient consistent evidence to recommended physical ergonomics interventions alone for reduction of the prevalence and severity of LBP (Level C). There is insufficient consistent evidence to recommended physical ergonomics interventions alone for reduction of [reported] back injuries, occupational or compensable LBP (Level C). There is some evidence that, to be successful, a physical ergonomics programme would need an organisational dimension and involvement of the workers (Level B). There is insufficient evidence to specify precisely the useful content of such interventions (Level C), and the size of any effect may be modest.

#### Organisational ergonomics

Recommendation.

There is insufficient consistent evidence to recommend stand-alone work organisational interventions alone for prevention in LBP (Level C), yet such interventions could, in principle, enhance the effectiveness of physical ergonomics programmes.

Modified work for return to work after sick leave due to LBP Recommendation.

Temporary modified work (which may include ergonomic workplace adaptations) can be recommended, when needed, in order to facilitate earlier return to work for workers sick listed due to LBP (Level B)

Table 4. Summary of recommendations of the interventions for prevention of LBP for workers (The COST B13 Working Group, 2004b)

Physical exercise may be recommended in prevention of LBP (Level A). Physical exercise may be recommended in prevention recurrence of LBP (Level A) and in prevention recurrence of

Traditional information/advice/instruction on biomechanics, lifting techniques, optimal postures etc is not recommended for prevention in LBP (Level A). there is insufficient evidence to recommended for or against psychosocial information delivered at the worksite (Level C), but information oriented toward promoting activity and improving coping, can promote a positive shift in beliefs (Level C). Whilst the evidence is not sufficiently consistent to recommend education in the prevention of recurrence of sick leave due to LBP (Level C), incorporating the messages from the accompanying clinical guidelines into workplace

Shoe inserts/shoe orthoses are not recommended for prevention in LBP (Level A). There is insufficient evidence to recommend for or against shoe in-soles, soft shoes, soft flooring or

There is insufficient consistent evidence to recommended physical ergonomics interventions alone for reduction of the prevalence and severity of LBP (Level C). There is insufficient consistent evidence to recommended physical ergonomics interventions alone for reduction of [reported] back injuries, occupational or compensable LBP (Level C). There is some evidence that, to be successful, a physical ergonomics programme would need an organisational dimension and involvement of the workers (Level B). There is insufficient evidence to specify precisely the useful content of such interventions (Level C), and the size of any effect may be

There is insufficient consistent evidence to recommend stand-alone work organisational interventions alone for prevention in LBP (Level C), yet such interventions could, in principle,

Temporary modified work (which may include ergonomic workplace adaptations) can be recommended, when needed, in order to facilitate earlier return to work for workers sick listed

Table 4. Summary of recommendations of the interventions for prevention of LBP for

Back belts/lumber supports are not recommended for prevention in LBP (Level A).

Shoe inserts, shoe orthoses, shoe in-soles, flooring and mats

enhance the effectiveness of physical ergonomics programmes.

Modified work for return to work after sick leave due to LBP

workers (The COST B13 Working Group, 2004b)

Physical exercise / physical activity

sick leave due to LBP (Level C).

Information / advice / instruction

information/advice is encouraged.

Back belts / lumber supports

antifatigue floor mats (Level D).

Recommendation.

Recommendation.

Physical ergonomics Recommendation.

Organisational ergonomics

Recommendation.

Recommendation.

due to LBP (Level B)

modest.

Recommendation.

Recommendation.

Fig. 7. Prevention and/or intervention of LBP are needed on the every stage (arrows).

### **3. Conclusion**

Many people suffer from LBP. It is considered that the lifetime prevalence of LBP ranged from 50% to 80% and about half of the population experienced LBP in a year. As occupational LBP can occur in most workers in various jobs, it is both an individual and social problems. Accidental LBP tends to occur in the morning (8:00-11:00) at the beginning of week. It is considered that there is the evidence that increased risk of LBP is associated with heavy physical work, manual material handling, awkward posture and whole body vibration among physical factors, and job dissatisfaction and low social support among the psychosocial factors and socioeconomic status (low education and occupational status) among the personal factors. These factors interact with the onset of LBP directly or indirectly. Therefore, employers must take measures to reduce the risk factors for LBP by improvement of the workplace, work task and work-organization designs, and education and training. Workers must take measures to prevent LBP similar to those undertaken by employers. There is evidence that physical exercise may be recommended in the prevention of LBP and the prevention of the recurrence of LBP. It is considered that prevention of LBP can be effective if the exercise programme matches the individuals, as there is contradictory evidence and any effect in reducing LBP by various general exercise programmes. We should take suitable measures fitting the stages (i.e. future LBP, present LBP and continuous LBP) to prevent LBP, disability and so on. Needless to say, it is important to make sure of the causes of LBP in the past, present and future. Therefore, health care professionals should understand the risk factors for LBP and fully understand the subjects with LBP and their circumstances. These should be applied to all workers.

#### **4. Acknowledgment**

I borrowed the books of occupational LBP and musculoskeletal disorders from Professor Kurumatani and Dr. Tomioka in the Department of Community Health and Epidemiology, Nara Medical University, School of Medicine. I thank them deeply.

### **5. References**


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**2** 

*Spain* 

E. Latorre Marques

*University of Zaragoza,* 

**The Treatment of Low Back** 

*Spanish Working Group of COST B13 Program,* 

**Pain and Scientific Evidence** 

*Dep. of Anesthesiology, "Miguel Servet" Hospital, School of Medicine,* 

Low back pain (LBP) is one of most prevalent and controversial diseases for clinical management by multiple factors: resistance of practitioners to the application of the knowledge based on scientific evidence, limited use of reliable information, excessive and costly radiologic prescriptions either tendency to apply "innovative" technologies and, in

There is great variability in medical practice, even within developed countries, which can worsen the outcome of the treatment, unjustifiably increase the risk of iatrogenic, and

So guidelines are needed to reduce it; clinical practice is defined as: "assertions developed systematically for help to the doctor and the patient to make decisions appropriate in

If further complemented by analysis of cost effectiveness, they adapt to local differences, provide for improvement quality systems, are revised and can be summarized and

This chapter aims to disseminate knowledge contrasted on the management of low back pain based on scientific evidence and assist medical personnel in key facets as "Critical analysis", "Evidence-based medicine" "Design of working groups" and "Clinical trials methodology" for

In developed countries the prevalence is estimated between 12-33%, In the USA the annual amount are beetwen 22-65% and the 5th most common cause of doctor visits. (Deyo RA, 2006). A quarter of adults reported a duration of episode of at least one week. (Carey

The costs generated are high, medical treatment is estimated between 9000 and 19000 \$ per patient per year, and interventions around 19000 (Straus BN, 2002). Approximately 5% of

some cases, to satisfy wishes patients (Cabana MD, 1999).

clinical and specific circumstances" (Field MJ & Lohr KN, 1990).

**2. Costs and scientific evidence of low back pain** 

disseminated by various means, we will largely achieve the desired goal.

the elaboration of a multidisciplinary and improved clinical practice guideline.

needlessly increase healthcare costs.

**1. Introduction** 

TS,1996).

Yao, W., et al. (2011). A cross-sectional survey of non-specific low back pain among 2083 schoolchildren in China. *Spine*, Vol.36, No.22, (October 2011), pp.1885-1890, ISSN 0362-2436

## **The Treatment of Low Back Pain and Scientific Evidence**

E. Latorre Marques *Spanish Working Group of COST B13 Program, Dep. of Anesthesiology, "Miguel Servet" Hospital, School of Medicine, University of Zaragoza, Spain* 

#### **1. Introduction**

32 Low Back Pain

Yao, W., et al. (2011). A cross-sectional survey of non-specific low back pain among 2083

0362-2436

schoolchildren in China. *Spine*, Vol.36, No.22, (October 2011), pp.1885-1890, ISSN

Low back pain (LBP) is one of most prevalent and controversial diseases for clinical management by multiple factors: resistance of practitioners to the application of the knowledge based on scientific evidence, limited use of reliable information, excessive and costly radiologic prescriptions either tendency to apply "innovative" technologies and, in some cases, to satisfy wishes patients (Cabana MD, 1999).

There is great variability in medical practice, even within developed countries, which can worsen the outcome of the treatment, unjustifiably increase the risk of iatrogenic, and needlessly increase healthcare costs.

So guidelines are needed to reduce it; clinical practice is defined as: "assertions developed systematically for help to the doctor and the patient to make decisions appropriate in clinical and specific circumstances" (Field MJ & Lohr KN, 1990).

If further complemented by analysis of cost effectiveness, they adapt to local differences, provide for improvement quality systems, are revised and can be summarized and disseminated by various means, we will largely achieve the desired goal.

This chapter aims to disseminate knowledge contrasted on the management of low back pain based on scientific evidence and assist medical personnel in key facets as "Critical analysis", "Evidence-based medicine" "Design of working groups" and "Clinical trials methodology" for the elaboration of a multidisciplinary and improved clinical practice guideline.

#### **2. Costs and scientific evidence of low back pain**

In developed countries the prevalence is estimated between 12-33%, In the USA the annual amount are beetwen 22-65% and the 5th most common cause of doctor visits. (Deyo RA, 2006). A quarter of adults reported a duration of episode of at least one week. (Carey TS,1996).

The costs generated are high, medical treatment is estimated between 9000 and 19000 \$ per patient per year, and interventions around 19000 (Straus BN, 2002). Approximately 5% of

The Treatment of Low Back Pain and Scientific Evidence 35

episodes, have been visited and treated, and many of them being farmers on their own (Blau

In Europe lifetime prevalence reaches 59% (Veerle Hermans, 2000), in working population

The peril of LBP at work affect more frequently to the agriculture, fisheries, and construction. The most common body location is the back (Eurobarometer 2007) (Figure 1)

**Locations of pain restricting activity** 

**Head 6 %** 

**Neck / Shoulder 7 %** 

**Low back 11 %** 

**Knees 8%** 

**Ankle/Foot 5 %** 

Fig. 1. Special Eurobarometer 272e/Wave 66.2 requested by Directorate General SANCO of

Annual scientific production is estimated to be close to 900,000 publications, which nearly 40000 are medical. Exponential growth since 1970, thanks to the development of basic sciences such as mathematics, statistical analysis, computer engineering, the epidemiology

The number of systematic reviews and Meta-analysis in Biomedical Sciences published per year, is high and increasing, only in English reaches the 2,500. Despite the efforts made with certain "resources" and "Declarations" that contemplate later, studies show deficiencies in quality and few demonstrate impact of improvement initiatives or inclusion on editorial

Try to standardize clinic practices through diagnostic and therapeutic "protocols" that contemplated management diagrams but were due more to a development consensus and panels of experts; that is why a group of epidemiologists from Mc Master University

with up to 85% recurrence (The bone and joint decade Report 2005).

Jn. & Logue V, 1978).

European Commission 2003-2007

**2.2 Scientific evidence** 

and biology amongst others.

criteria (Moher D the al., 2007).

the population with disability, generates 75% of healthcare costs for low back pain (Frymoyer JW, 1991).

Those who attend care doctor however achieve rapid intensity improvements of pain (58%), disability (58%) and ease returning to work (2%) (Pengel LHM, 2003). But relapses are very frequent, 60-75% of patients may present at least one of year (Gatchel RJ, 1995).

On the other hand there are many options for evaluation and treatment of back pain, but little consensus regarding the appropriate use if diagnostic and treatment media, excessive variation for example indication of surgery, in USA is five times higher than Europe (Cherkin DC, 1994). Few technologies have often proved or ineffective and even damaging, some based on studies with few benefits.

There was an increase of 235% between 1997-2006 interventionist techniques in USA between 2002-2006 increased to 22%, this growth was parallel to a rise in the prevalence of pain due to an improvement of diagnostic means, and progress new injection techniques guided by fluoroscopy. Lifetime prevalence of spinal pain was 54-80% (Walker BF, 2000).

There are significant geographic variations, duration and chronicity also disputes, 90% of attacks are resolved in 6 weeks, 5-10% of patients develop persistent pain, however despite believing that there will be more episodes, are frequent relapses (4-10%) (Nachemson A, 2000).

The "Eurobarometer" 2003-2007 analiyze various aspects of European citizens health, is a part of the European Commission Health Strategy. Musculoskeletal problems (bone, muscles and joints) affects 22 per cent population, a third of respondents (32%) had experienced some pain week prior to the survey. Pain most common type was low back,affects 67 million Europeans, became apparent factors demographic. The 55 age group are the most likely to say they experienced restrictive pain (44%) (Special Eurobarometer, 2007).

Each year one in five adults have low back pain, (Cassidy JD, 2005) to the silent suffering back is the second location more frequent of pain (Watkins et al., 2006). However 5-15% of acute cases with an established cause should be identified, chronic pain lasts more than 3 months and affects 10% of cases with high annual costs to 100-200 billion \$ (Katz JN, 2006). Few documents provide advantages or outcomes assessment, and the first international guide for prevention and management of chronic cases was published 2006 (Airaksinen O, et al. 2006).

Low back pain is the most common cause and orthopedic, industrial, face of disability of workers under 45. Those who have medical care 25-40% have radiated pain and only 2% have strong findings of good surgical results forecasts for the nerve root decompression (Saal JA et al., 1990).

Those with signs of disk herniation, one in half recover a suitable tolerance of daily activities so dismiss the surgery.

Back is one of the most frequently reasons for primary care visit (Saal JA, 1990), sciatica slows recovery and is considered announcement of a significant loss of tolerance to activities. There is a significant cultural influence on disability appreciation, 20% of Swedes who deny having had problems with his back causing disability, continue the work during

the population with disability, generates 75% of healthcare costs for low back pain

Those who attend care doctor however achieve rapid intensity improvements of pain (58%), disability (58%) and ease returning to work (2%) (Pengel LHM, 2003). But relapses are very

On the other hand there are many options for evaluation and treatment of back pain, but little consensus regarding the appropriate use if diagnostic and treatment media, excessive variation for example indication of surgery, in USA is five times higher than Europe (Cherkin DC, 1994). Few technologies have often proved or ineffective and even damaging,

There was an increase of 235% between 1997-2006 interventionist techniques in USA between 2002-2006 increased to 22%, this growth was parallel to a rise in the prevalence of pain due to an improvement of diagnostic means, and progress new injection techniques guided by fluoroscopy. Lifetime prevalence of spinal pain was 54-80% (Walker BF, 2000).

There are significant geographic variations, duration and chronicity also disputes, 90% of attacks are resolved in 6 weeks, 5-10% of patients develop persistent pain, however despite believing that there will be more episodes, are frequent relapses (4-10%) (Nachemson A,

The "Eurobarometer" 2003-2007 analiyze various aspects of European citizens health, is a part of the European Commission Health Strategy. Musculoskeletal problems (bone, muscles and joints) affects 22 per cent population, a third of respondents (32%) had experienced some pain week prior to the survey. Pain most common type was low back,affects 67 million Europeans, became apparent factors demographic. The 55 age group are the most likely to say they experienced restrictive pain (44%) (Special Eurobarometer,

Each year one in five adults have low back pain, (Cassidy JD, 2005) to the silent suffering back is the second location more frequent of pain (Watkins et al., 2006). However 5-15% of acute cases with an established cause should be identified, chronic pain lasts more than 3 months and affects 10% of cases with high annual costs to 100-200 billion \$ (Katz JN, 2006). Few documents provide advantages or outcomes assessment, and the first international guide for prevention and management of chronic cases was published 2006 (Airaksinen O,

Low back pain is the most common cause and orthopedic, industrial, face of disability of workers under 45. Those who have medical care 25-40% have radiated pain and only 2% have strong findings of good surgical results forecasts for the nerve root decompression

Those with signs of disk herniation, one in half recover a suitable tolerance of daily activities

Back is one of the most frequently reasons for primary care visit (Saal JA, 1990), sciatica slows recovery and is considered announcement of a significant loss of tolerance to activities. There is a significant cultural influence on disability appreciation, 20% of Swedes who deny having had problems with his back causing disability, continue the work during

frequent, 60-75% of patients may present at least one of year (Gatchel RJ, 1995).

(Frymoyer JW, 1991).

2000).

2007).

et al. 2006).

(Saal JA et al., 1990).

so dismiss the surgery.

some based on studies with few benefits.

episodes, have been visited and treated, and many of them being farmers on their own (Blau Jn. & Logue V, 1978).

In Europe lifetime prevalence reaches 59% (Veerle Hermans, 2000), in working population with up to 85% recurrence (The bone and joint decade Report 2005).

The peril of LBP at work affect more frequently to the agriculture, fisheries, and construction. The most common body location is the back (Eurobarometer 2007) (Figure 1)

Fig. 1. Special Eurobarometer 272e/Wave 66.2 requested by Directorate General SANCO of European Commission 2003-2007

#### **2.2 Scientific evidence**

Annual scientific production is estimated to be close to 900,000 publications, which nearly 40000 are medical. Exponential growth since 1970, thanks to the development of basic sciences such as mathematics, statistical analysis, computer engineering, the epidemiology and biology amongst others.

The number of systematic reviews and Meta-analysis in Biomedical Sciences published per year, is high and increasing, only in English reaches the 2,500. Despite the efforts made with certain "resources" and "Declarations" that contemplate later, studies show deficiencies in quality and few demonstrate impact of improvement initiatives or inclusion on editorial criteria (Moher D the al., 2007).

Try to standardize clinic practices through diagnostic and therapeutic "protocols" that contemplated management diagrams but were due more to a development consensus and panels of experts; that is why a group of epidemiologists from Mc Master University

The Treatment of Low Back Pain and Scientific Evidence 37

In Europe from population-based studies on low back pain (Biering Sorensen f., 1983), National cost-effectiveness in Netherlands (Van Tulder MW, 1995) and systematized the Cochrane Cochrane Collaboration reviews, of clinical practice guidelines amounts a step, based on scientific evidence and cost-effectiveness. Articulate local adaptations for all national health systems in European Union, be revised and therefore adaptable to further

The COST B13 Guide is pan-European, multidisciplinary, based on scientific evidence, publicly funded without participation of the industry or profit institutions. It provides for comprehensive management of acute, chronic low back pain and its prevention (Van Tulder MW, 2002). In the Spanish adaptation recommendations relating to acute and chronic low back pain were merged into a single temporal sequence, in order to improve clinical practice application, ordering implementation of technologies recommended depending on type of patients and scientific evidence, efficacy, effectiveness and efficiency, and safety (Latorre E 2008). Added a declaration of conflicts of interest of its members, and followed the collaboration criteria AGREE applying this instrument to improve quality

In general, Low back pain is "the pain between the costal margins and the inferior gluteal folds, it is influenced by physical activities and postures, accompanied by painful limitation

"Common Low Back Pain is not related to fractures, ankylosis, direct trauma or systemic

Specific low back pain is related to specific pathologies and can be diagnosed early through warning signs (Neoplasm, Infectious,vascular,metabolic,or endocrine related) (Wipf & Deyo

The distribution of the cause of LBP are by frequency: Common low back pain 90%, symptomatic herniated disk 3-4%, ankylosis 0.3 - 5%, compression fractures 4%, and spinal

Episodes acute last less than 3 months in more than 90% of the cases, which are usually benign, and they can be treated with simple steps, usually this corresponds to the type "Nonspecific" but the rest of the cases may be due to other causes and therefore must diagnose and

Chronic pain lasts more than 3 months and constitutes about 10% of cases, but which

This classification may seem simplistic since in many cases the pain yields around 6 weeks, why is has introduced the term subacute to see episodes that reach between 6 and 12 weeks and are warning signs ("Yellow flags") that requires new evaluations and treatments. (Burton A.K. & COST B13 working group 2006). The key to preventing acute pain

treat "specifically" and quickly (Van Tulder MW & COST B13 working group 2006).

scientific evidence.

(www.agreecollaboration.org ).

conditions" (or "Non-Specific").

malignancy 0.7% (Van Tulder, 2006).

Pain can occur in different ways:

generates higher costs.

**3.1 Concept and types** 

RA, 1995).

**3. Which is Low Back Pain (LBP)?** 

of motion, frequently associated with referred pain".

(Sackett) published a series of articles on "how to interpret the publications", especially those of a clinical and experimental nature.

Born in 1980s, Canadian Medical Association Journal by proposing term "critical appraisal" to describe application of basic rules that allow to find evidence in scientific literature, converted by Sackett in "appreciation criticism in header of patient", to extend clinical practice.

In 90´s Guyatt coined term "evidence-based medicine" which should apply from University education to clinical practice, to provide efficiency and effectiveness in clinical events and individualized way (Guyatt GH, Renie D, 1991). Emerging entities as Collaboration Cochrane made systematic revisions of scientific literature by extracting truly relevant studies through Meta-analysis and promoting the edition of clinical practice guidelines based on scientific evidence (www.cochrane.org).

Due to variability of medical practice, not consistent with scientific evidence, and profusion of scientific literature with poor quality, emerging entities as CONSORT (1994) which are intended to implement the quality of work and scientific tests in health area. Through global outreach programs that use internet resources developed during the past 25 years (www.consort-statement.org ).

#### **2.3 Health economics**

Health systems in the West have been developped and consolidated with the hospital network, organization of primary care which began to generate significant economic costs, the European Community adopted a common policy called "System of Social Welfare" which provided for the right to universal and State health care whose costs are loaded to state budgets and they did recover through taxes fairly distinct. Soon will detect need for implementation principles of Economics. Comes the concept of "Clinical Governance"

Within this trend, large companies and institutions begin became interested in the policies of containment of costs and including derivatives of industrial casualties (Spengler D, 1986) and the financial outlay to cover the fees of workers and medical care costs (Frymoyer J, 1991).

So develop epidemiological research on diseases most prevalent in the industry (Bergquist-Ullman M, 1977) in parallel with studies of Biomechanics and ergonomics, with adoption of measures of legislation to limit the burden on labour and improve the productivity and cost.

In 1991 Deyo RA publishes one research and collaborators which examines all aspects related to low back pain and its impact labor, health, economic and social system is entering a crisis.

First Clinical Practice Guidelines (CPG) were developed in order to manage more prevalent diseases; in 1994 the Agency for Health Care Policy Research published the "CPG for management of acute low back pain in adults" based on consensus (Bigos S, 1994).

Subsequently they adapt and develop guides aimed at acute low back pain as "Committee on health of New Zealand" (New Zealand acute low back pain guide 1997) which analyses risk factors for long-term disability and work loss. Improvement of aspects such as diagnosis and treatment as the case of the Guide to Australasia (Bogduk N, 1999).

In Europe from population-based studies on low back pain (Biering Sorensen f., 1983), National cost-effectiveness in Netherlands (Van Tulder MW, 1995) and systematized the Cochrane Cochrane Collaboration reviews, of clinical practice guidelines amounts a step, based on scientific evidence and cost-effectiveness. Articulate local adaptations for all national health systems in European Union, be revised and therefore adaptable to further scientific evidence.

The COST B13 Guide is pan-European, multidisciplinary, based on scientific evidence, publicly funded without participation of the industry or profit institutions. It provides for comprehensive management of acute, chronic low back pain and its prevention (Van Tulder MW, 2002). In the Spanish adaptation recommendations relating to acute and chronic low back pain were merged into a single temporal sequence, in order to improve clinical practice application, ordering implementation of technologies recommended depending on type of patients and scientific evidence, efficacy, effectiveness and efficiency, and safety (Latorre E 2008). Added a declaration of conflicts of interest of its members, and followed the collaboration criteria AGREE applying this instrument to improve quality (www.agreecollaboration.org ).

### **3. Which is Low Back Pain (LBP)?**

#### **3.1 Concept and types**

36 Low Back Pain

(Sackett) published a series of articles on "how to interpret the publications", especially those

Born in 1980s, Canadian Medical Association Journal by proposing term "critical appraisal" to describe application of basic rules that allow to find evidence in scientific literature, converted by Sackett in "appreciation criticism in header of patient", to extend clinical

In 90´s Guyatt coined term "evidence-based medicine" which should apply from University education to clinical practice, to provide efficiency and effectiveness in clinical events and individualized way (Guyatt GH, Renie D, 1991). Emerging entities as Collaboration Cochrane made systematic revisions of scientific literature by extracting truly relevant studies through Meta-analysis and promoting the edition of clinical practice guidelines

Due to variability of medical practice, not consistent with scientific evidence, and profusion of scientific literature with poor quality, emerging entities as CONSORT (1994) which are intended to implement the quality of work and scientific tests in health area. Through global outreach programs that use internet resources developed during the past 25 years

Health systems in the West have been developped and consolidated with the hospital network, organization of primary care which began to generate significant economic costs, the European Community adopted a common policy called "System of Social Welfare" which provided for the right to universal and State health care whose costs are loaded to state budgets and they did recover through taxes fairly distinct. Soon will detect need for implementation principles of Economics. Comes the concept of "Clinical Governance"

Within this trend, large companies and institutions begin became interested in the policies of containment of costs and including derivatives of industrial casualties (Spengler D, 1986) and the financial outlay to cover the fees of workers and medical care costs (Frymoyer J,

So develop epidemiological research on diseases most prevalent in the industry (Bergquist-Ullman M, 1977) in parallel with studies of Biomechanics and ergonomics, with adoption of measures of legislation to limit the burden on labour and improve the productivity and cost. In 1991 Deyo RA publishes one research and collaborators which examines all aspects related to low back pain and its impact labor, health, economic and social system is entering

First Clinical Practice Guidelines (CPG) were developed in order to manage more prevalent diseases; in 1994 the Agency for Health Care Policy Research published the "CPG for

Subsequently they adapt and develop guides aimed at acute low back pain as "Committee on health of New Zealand" (New Zealand acute low back pain guide 1997) which analyses risk factors for long-term disability and work loss. Improvement of aspects such as

management of acute low back pain in adults" based on consensus (Bigos S, 1994).

diagnosis and treatment as the case of the Guide to Australasia (Bogduk N, 1999).

of a clinical and experimental nature.

based on scientific evidence (www.cochrane.org).

(www.consort-statement.org ).

**2.3 Health economics** 

1991).

a crisis.

practice.

In general, Low back pain is "the pain between the costal margins and the inferior gluteal folds, it is influenced by physical activities and postures, accompanied by painful limitation of motion, frequently associated with referred pain".

"Common Low Back Pain is not related to fractures, ankylosis, direct trauma or systemic conditions" (or "Non-Specific").

Specific low back pain is related to specific pathologies and can be diagnosed early through warning signs (Neoplasm, Infectious,vascular,metabolic,or endocrine related) (Wipf & Deyo RA, 1995).

The distribution of the cause of LBP are by frequency: Common low back pain 90%, symptomatic herniated disk 3-4%, ankylosis 0.3 - 5%, compression fractures 4%, and spinal malignancy 0.7% (Van Tulder, 2006).

Pain can occur in different ways:

Episodes acute last less than 3 months in more than 90% of the cases, which are usually benign, and they can be treated with simple steps, usually this corresponds to the type "Nonspecific" but the rest of the cases may be due to other causes and therefore must diagnose and treat "specifically" and quickly (Van Tulder MW & COST B13 working group 2006).

Chronic pain lasts more than 3 months and constitutes about 10% of cases, but which generates higher costs.

This classification may seem simplistic since in many cases the pain yields around 6 weeks, why is has introduced the term subacute to see episodes that reach between 6 and 12 weeks and are warning signs ("Yellow flags") that requires new evaluations and treatments. (Burton A.K. & COST B13 working group 2006). The key to preventing acute pain

The Treatment of Low Back Pain and Scientific Evidence 39

This multidimensional mechanism has generated different handlings for different specialties for decades producing poor results, however since publication of Bio-psycho-social model in 1977, with adoption of management models based on evidence and cost-effectiveness, has been creating multidisciplinary teams integrating information and improving outcomes

However he tends in some areas to excessive psycho-social reductionism and based exclusively on this model of treatment, leaving the Neurophysiologic model which based

Clinical application of nerve blockade or surgical techniques on the focus and pain pathway, has emerged as response to need for action on physical structures that generate, but arising in many cases studies with poor methodological quality and so not supported Meta-

Techniques "not recommended" in various guides ( COST B13, RCGP UK) are being revised based on improvements in the quality of study design, include studies of cost-effectiveness,

The Begining of medicine until today, the concern has been to provide the best possible assistance, applying means proper diagnosis and optimal treatment. The Hippocratic

Since the development of science in the industrial era until today, we have attended to the improvement of the scientific method, and in turn the dissemination of information, which in recent years is massive. However in what affects the biomedical sciences, have originated important defects because at present we do not have instruments of ratification of the veracity of the information and analysis to make checks at the same speed that discovered

At the moment we have a method, perfected from the 20th century, involving the application of the "Critical Analysis" of the scientific literature, and "Systematic Reviews" & "Meta-Analysis" for development of clinical practice guidelines based on what really is

However this process is expensive, slow and is occasionally provide obsolete results at the

The scientific method have been based on the three classical premises (elaboration of hypothesis, experimentation and analysis, and conclusion) to another more complex process that we intend to explain to the reader and allows you to start or improve their skills in the development of strategies for applied research in the clinic practice, following our

The script indicated below is intended to achieve a systematization to avoid biases that are

generated throughout the process and thus increase the reliability of the results:

helpful, so try to minimize the variability of medical practice and clinical research.

part of the treatment on interventional techniques (Manchikanti L, 2009).

and therefore possibly be integrated into new "reviews" (Latorre E., 2008).

**4. Critical appraisal & methodology of scientific evidence** 

(Kovacs FM, 2006).

analysis, generating controversy.

principle is relevant for people with pain.

new treatments or diagnostic applications.

time of its publication and dissemination.


experiences.

occurrence and chronicity is implementation of preventive measures (Burton AK & COST B13 working group 2006).

Can be integrated into low back pain clinical course; diagnostic, therapeutic and preventive actions so optimize long term results (table 1).


Table 1. Current status and management of LBP and warning signs changed (Van Tulder & Araksinen 2006)

#### **3.2 Basis of spinal pain**

Not only low-back pain is a clinical entity, but also a psycho-social and economic problem.

It seems that relationship exists between adoption of bipedal position and biomechanical changes of musculoskeletal, spine aging, loss of exercise capacity and stamina, working conditions, personal expectations, psychological state, intersocial relationship, with low back pain. These aspects are detailed in other chapters, but introduce variables that increase the complexity of diagnosis management and treatment results.

occurrence and chronicity is implementation of preventive measures (Burton AK & COST

Can be integrated into low back pain clinical course; diagnostic, therapeutic and preventive

**Course of LBP Red Flags Yellow Flags**

*Emotional problems*  Depression, low morale, and social withdrawal

*Use / Abuse of psicho-*

*Inappropriate attitudes and beliefs about pain* 

"pain is harmful or

"passive, rather than active, treatment will be beneficial" *Inappropriate pain* 

Fear and reduced activity levels *Social, Financial problems* 

*Labour disputes* 

disabling"

*behavior* 

*mimetics*

Deformity, not flexion of 5th Bad general State, fever Trauma or Neoplasms Use of corticosteroids

Immunodeficiency, AIDS

*Urgent* : Paresis, loss of control of sphincters, "saddle" anesthesia *Consultation* : 6 Weeks of treatment, limitation of ambulation. Radicular pain > 6 months + image of spinal

Table 1. Current status and management of LBP and warning signs changed (Van Tulder &

Not only low-back pain is a clinical entity, but also a psycho-social and economic problem. It seems that relationship exists between adoption of bipedal position and biomechanical changes of musculoskeletal, spine aging, loss of exercise capacity and stamina, working conditions, personal expectations, psychological state, intersocial relationship, with low back pain. These aspects are detailed in other chapters, but introduce variables that increase

*Systemic disease:* Pain < 20 or > 50 age. Thoracic spine pain Deficit Neurologic

Addictions

*Surgery* 

stenosis

the complexity of diagnosis management and treatment results.

B13 working group 2006).

*Acute (< 6 weeks))* Information Rule out red flags No routine Radiology Stay active + Analgesics Muscle relaxants (optional)

Aware Yellow Flags

*Subacute (6-12 weeks)* 

Multidisciplinary Occupational

*Chronic (> 12 weeks)*  Low disability: simple

Severe disability: biopsychosocial

Araksinen 2006)

**3.2 Basis of spinal pain** 

programme for workers?

therapy

therapies

Expectations of patient Regular Re-assessment Active treatments Cognitive behavioral

actions so optimize long term results (table 1).

This multidimensional mechanism has generated different handlings for different specialties for decades producing poor results, however since publication of Bio-psycho-social model in 1977, with adoption of management models based on evidence and cost-effectiveness, has been creating multidisciplinary teams integrating information and improving outcomes (Kovacs FM, 2006).

However he tends in some areas to excessive psycho-social reductionism and based exclusively on this model of treatment, leaving the Neurophysiologic model which based part of the treatment on interventional techniques (Manchikanti L, 2009).

Clinical application of nerve blockade or surgical techniques on the focus and pain pathway, has emerged as response to need for action on physical structures that generate, but arising in many cases studies with poor methodological quality and so not supported Metaanalysis, generating controversy.

Techniques "not recommended" in various guides ( COST B13, RCGP UK) are being revised based on improvements in the quality of study design, include studies of cost-effectiveness, and therefore possibly be integrated into new "reviews" (Latorre E., 2008).

### **4. Critical appraisal & methodology of scientific evidence**

The Begining of medicine until today, the concern has been to provide the best possible assistance, applying means proper diagnosis and optimal treatment. The Hippocratic principle is relevant for people with pain.

Since the development of science in the industrial era until today, we have attended to the improvement of the scientific method, and in turn the dissemination of information, which in recent years is massive. However in what affects the biomedical sciences, have originated important defects because at present we do not have instruments of ratification of the veracity of the information and analysis to make checks at the same speed that discovered new treatments or diagnostic applications.

At the moment we have a method, perfected from the 20th century, involving the application of the "Critical Analysis" of the scientific literature, and "Systematic Reviews" & "Meta-Analysis" for development of clinical practice guidelines based on what really is helpful, so try to minimize the variability of medical practice and clinical research.

However this process is expensive, slow and is occasionally provide obsolete results at the time of its publication and dissemination.

The scientific method have been based on the three classical premises (elaboration of hypothesis, experimentation and analysis, and conclusion) to another more complex process that we intend to explain to the reader and allows you to start or improve their skills in the development of strategies for applied research in the clinic practice, following our experiences.

The script indicated below is intended to achieve a systematization to avoid biases that are generated throughout the process and thus increase the reliability of the results:


The Treatment of Low Back Pain and Scientific Evidence 41

The Evidence-based medicine (on Systematic reviews & Meta-analysis), have become increasingly in health care. They are often used as a starting point for developing clinical

A systematic review is a review of to clearly formulated question that uses systematic and explicit methods to identify, select and critically appraise relevant research, and to collect

Meta-analysis refers to the use of statistical techniques in a systematic review to integrate

REVIEW *Attempt of synthesis of findings and conclusions of two or* 

SYSTEMATIC *Review with exhaustive identification of all literature, quality* 

META-ANALYSIS *Systematic review incorporating a specific statistical strategy* 

Table 2. Sackett D et al. Clinical Epidemiology: A basic science for clinical medicine 2nd ed.

Unfortunately medical reviews are subjective, scientifically unsound, and often inefficient (Group VPC-IRYS, 2005). Strategies for identifying and selecting information are rarely defined. Collected information is reviewed haphazardly with little attention to systematic assessment of quality. Under such circumstances, cogent summarization is an arduous not

Experts from different areas, such as appropriate specialists, statisticians, and research methodologists, can be used both to help develop standardized appraisal forms and to rank data.Resources used for these purposes have also access program and provide training and

They are varied and known of published articles (Medline, Lilacs, Embase) and unpublished as recognized research centers internationally accessible through institutional web pages.

To address suboptimal reporting of meta-analysis, an international group developed a guidance called "QUOROM Statement" (QUality Of Reporting Of Meta-analysis), which focused reporting meta-analysis of randomized controlled trials (RCT) (Moher D, 1999).

Stimulus for systematic reviews has come from hand of Cochrane Collaboration. Archie Cochrane was a wake-up call to underline how collected evidence through RCTs could

*more publications related to a theme.* 

*assessment and synthesis of results of a given subject.* 

*bring together results of several studies on a single estimate.* 

and analyze data from the studies that are included in the review.

practice guidelines (Green S et al., 2007).

the results of included studies.

Little, Brown & Company, 1991.

support for clinical research, are the following:

**4.2.1 Search, bibliographic databases systems.** 

**4.2 Resources** 

insurmountable task.

**4.2.2 QUOROM Statement** 

**4.2.3 COCHRANE Collaboration** 

affect medical practice.


We understand that they may be useful basic facets as the description of the method of critical analysis of the publications and resources for clinical research provided by various institutions and entities, which have electronic edition of easy access, which includes chapters of methodology and practical aid as well as the possibility of on-line training. Given the limited scope of the chapter we have narrated in the first place a brief description, but we urge strongly are consulted for its value.

#### **4.1 Critical reading**

Critical reading is a technique that allows increase effectiveness our reading, acquiring necessary skills to exclude low quality scientific articles and accept others to help our decision-making process for care of patients.

Scientific articles should be evaluated in three aspects:

Validity:

Confident in validity of results? The criteria of methodological validity articles are different for different questions: treatment, diagnosis, prognosis, economic evaluation... Depending on validity, an article may be classified in evidence levels scale, and grades of recommendation.

Effects and Precision:

How do results measure the effect? Are results accurate?

Applicability:

Are these results in my middle applicable?

There are quality scales will help us evaluate job quality in a simple way. In the example before us, we used the "**Jadad quality scale"** to rate on a range of zero to 5 points:


There is also a rating system "**Validation Level Pain of Oxford"** (The Oxford Pain Validity Scale: IPOs) with a maximum of 16 points.

This scale has been developed to test internal validity pain trials and their results. The scale assigns points to an essay based on the number of patients in each treatment group, whether or not study satisfies criteria of blind or not and if this is correct, used results, summary test statistics and if these results or evidence were properly employed.

The Evidence-based medicine (on Systematic reviews & Meta-analysis), have become increasingly in health care. They are often used as a starting point for developing clinical practice guidelines (Green S et al., 2007).

A systematic review is a review of to clearly formulated question that uses systematic and explicit methods to identify, select and critically appraise relevant research, and to collect and analyze data from the studies that are included in the review.

Meta-analysis refers to the use of statistical techniques in a systematic review to integrate the results of included studies.


Table 2. Sackett D et al. Clinical Epidemiology: A basic science for clinical medicine 2nd ed. Little, Brown & Company, 1991.

#### **4.2 Resources**

40 Low Back Pain

We understand that they may be useful basic facets as the description of the method of critical analysis of the publications and resources for clinical research provided by various institutions and entities, which have electronic edition of easy access, which includes chapters of methodology and practical aid as well as the possibility of on-line training. Given the limited scope of the chapter we have narrated in the first place a brief description,

Critical reading is a technique that allows increase effectiveness our reading, acquiring necessary skills to exclude low quality scientific articles and accept others to help our

Confident in validity of results? The criteria of methodological validity articles are different for different questions: treatment, diagnosis, prognosis, economic evaluation... Depending on validity, an article may be classified in evidence levels scale, and grades of

There are quality scales will help us evaluate job quality in a simple way. In the example



There is also a rating system "**Validation Level Pain of Oxford"** (The Oxford Pain Validity

This scale has been developed to test internal validity pain trials and their results. The scale assigns points to an essay based on the number of patients in each treatment group, whether or not study satisfies criteria of blind or not and if this is correct, used results, summary test

before us, we used the "**Jadad quality scale"** to rate on a range of zero to 5 points:

explained and suitable gives 1 point and if wasn't it him remains.

statistics and if these results or evidence were properly employed.



but we urge strongly are consulted for its value.

decision-making process for care of patients.

Scientific articles should be evaluated in three aspects:

How do results measure the effect? Are results accurate?

Are these results in my middle applicable?

Scale: IPOs) with a maximum of 16 points.

**4.1 Critical reading** 

Validity:

recommendation.

Applicability:

Effects and Precision:



Unfortunately medical reviews are subjective, scientifically unsound, and often inefficient (Group VPC-IRYS, 2005). Strategies for identifying and selecting information are rarely defined. Collected information is reviewed haphazardly with little attention to systematic assessment of quality. Under such circumstances, cogent summarization is an arduous not insurmountable task.

Experts from different areas, such as appropriate specialists, statisticians, and research methodologists, can be used both to help develop standardized appraisal forms and to rank data.Resources used for these purposes have also access program and provide training and support for clinical research, are the following:

#### **4.2.1 Search, bibliographic databases systems.**

They are varied and known of published articles (Medline, Lilacs, Embase) and unpublished as recognized research centers internationally accessible through institutional web pages.

#### **4.2.2 QUOROM Statement**

To address suboptimal reporting of meta-analysis, an international group developed a guidance called "QUOROM Statement" (QUality Of Reporting Of Meta-analysis), which focused reporting meta-analysis of randomized controlled trials (RCT) (Moher D, 1999).

#### **4.2.3 COCHRANE Collaboration**

Stimulus for systematic reviews has come from hand of Cochrane Collaboration. Archie Cochrane was a wake-up call to underline how collected evidence through RCTs could affect medical practice.

The Treatment of Low Back Pain and Scientific Evidence 43

Detailed tables and diagrams information is available at http://www.Prisma-statement.org. Main differences between QUOROM (Quality Of Reporting Of Meta-analysis) and PRISMA

 Flow diagram more detailed and informative. PRISMA based on randomized clinical trials, and have useful for meta-analysis as QUOROM, trials continues with total number of records or unique citations and ends with individual studies included in

Establishes differences at each stage process between records or references, articles to

Includes format peak (description of participants, interventions, comparisons and

Is a network of resource development aimed at improving the quality of publications in health sciences, this has provided assistance through its website ( http://www.equatornetwork.org/) that allow a single researcher as well as groups, teach design guidelines for

This led to clinical trials improve quality methodology and resources publication as CONSORT statement, 25 items checklist set of recommendations and a flow diagram

Objetives are to assist preparation, transparency, critical review and interpretation of

The first version of 2001 has been revised and perfected in 2010 and includes on its website (http://www.consort-statement.org/) additional resources such as CONSORT "Explanation

Pureed both access to Downloads, Evidence Database, Glossary, Related Instruments, and

Members of CONSORT Group continually monitoring literature. Information gleaned from these efforts provides an evidence base on which to update CONSORT statement. We add, drop, or modify items based on that evidence and recommendations of "CONSORT Group", an international and eclectic group of clinical reserarchers, epidemiologists, statisticians, and biomedical editors. More than 400 journals, published around the world and in many

and Elaboration" document and CONSORT Library of examples of good reporting.

Extent text increases expense of improving clarity and transparency of information.

**4.2.6 EQUATOR Network (Enhancing the QUality and transparency Of Health** 

**4.2.7 CONSORT declaration (Consolidated Standards of Reporting Trials)** 

qualitative synthesis (systematic review) and quantitative (meta- analysis).

Explanation of previous Protocol to review and access medium.

Strategies for electronic search and evaluation risk bias.

developing quality and transparency. (Liberati A, 2009)




full and individual studies.

**Research) (Altman & Simera, 2008)** 

Randomized Controlled Trials (RCT).

link to Useful sites as for example EQUATOR

arethe relating to:

outcomes).

development progress.

Acknowledged that professionals interested in making their decisions based on the best evidence found had no real access to this information and much less elaborate results.

In 2008 changed "Cochrane Handbook Reviewer" version 5, which serves to help authors reviews explicit and systematic development. Collaboration also has interesting possibilities for training and development on its website and is accessible at http://www.cochranehandbook.org .

Available in Spanish, access is universal and free thanks to the subscription by Ministry of Health and Social Policy.

The edition of the Web site (Cochrane.es) is borne by the Iberoamerican Cochrane Centre located in "Hospital de la Santa Cruz and San Pablo" of the Autonomous University of Barcelona, also contribute to maintenance activities "Instituto de Salud Carlos III", as Ministry of Health.

Handbook Website offers a multitude aid to health professional, investigator or public. Includes resources for users of Cochrane Library plus, design reviews, introduction to authors research methodology in English, manual search and training. Access to finished clinical practice guides, program of skills of reading criticism, the Center for evidence-based medicine and evidence-based health care.

#### **4.2.4 Bandolier**

Bandolier is a health resource for physicians, evidence based, available over Internet (http://www.ebandolier.com ) print as a monthly magazine, primarily in United Kingdom. The wealth of information based on evidence that contains Bandolier appears mainly in form of short articles and systematic reviews on various conditions and medical interventions. Information submitted in concisely and already performed, mainly in "Number Needed to Treat" (NNT).

From Bandolier home page, is an Oxford Pain link Internet Site, with various systematic reviews summaries previously published on acute and chronic pain.

Another link leads to Pain Research Unit, Oxford, which contains detailed information on current and past research.

#### **4.2.5 PRISMA (PRoposal to Improve the publication of Systematic reviews and Meta-Analysis)**

QUORUM statement was published 1999 in order to establish objective standards that improve quality reporting randomized trials meta-analysis. Contains checklist with 18 sections that allow researchers and editors certify work quality that will be published, and a flow diagram describe the process.

PRISMA (2009) statement arises to update and expand aspects of QUORUM which had deficiencies and enable acceptance of editors those standards of quality. Consists of 27 items and a ellaboration process of guidelines as well as 7 tables that explain key aspects of methodology and conduction of systematic reviews. New features in PRISMA are: adoption of COCHRANE collaboration terminology, application extension scope, not only systematic reviews of randomized trials, but also for other study types. 4 new aspects are:


Acknowledged that professionals interested in making their decisions based on the best evidence found had no real access to this information and much less elaborate results.

In 2008 changed "Cochrane Handbook Reviewer" version 5, which serves to help authors reviews explicit and systematic development. Collaboration also has interesting possibilities for training and development on its website and is accessible at http://www.cochrane-

Available in Spanish, access is universal and free thanks to the subscription by Ministry of

The edition of the Web site (Cochrane.es) is borne by the Iberoamerican Cochrane Centre located in "Hospital de la Santa Cruz and San Pablo" of the Autonomous University of Barcelona, also contribute to maintenance activities "Instituto de Salud Carlos III", as

Handbook Website offers a multitude aid to health professional, investigator or public. Includes resources for users of Cochrane Library plus, design reviews, introduction to authors research methodology in English, manual search and training. Access to finished clinical practice guides, program of skills of reading criticism, the Center for evidence-based

Bandolier is a health resource for physicians, evidence based, available over Internet (http://www.ebandolier.com ) print as a monthly magazine, primarily in United Kingdom. The wealth of information based on evidence that contains Bandolier appears mainly in form of short articles and systematic reviews on various conditions and medical interventions. Information submitted in concisely and already performed, mainly in

From Bandolier home page, is an Oxford Pain link Internet Site, with various systematic

Another link leads to Pain Research Unit, Oxford, which contains detailed information on

**4.2.5 PRISMA (PRoposal to Improve the publication of Systematic reviews and Meta-**

QUORUM statement was published 1999 in order to establish objective standards that improve quality reporting randomized trials meta-analysis. Contains checklist with 18 sections that allow researchers and editors certify work quality that will be published, and a

PRISMA (2009) statement arises to update and expand aspects of QUORUM which had deficiencies and enable acceptance of editors those standards of quality. Consists of 27 items and a ellaboration process of guidelines as well as 7 tables that explain key aspects of methodology and conduction of systematic reviews. New features in PRISMA are: adoption of COCHRANE collaboration terminology, application extension scope, not only systematic

reviews of randomized trials, but also for other study types. 4 new aspects are:

reviews summaries previously published on acute and chronic pain.

handbook.org .

Health and Social Policy.

medicine and evidence-based health care.

"Number Needed to Treat" (NNT).

flow diagram describe the process.

current and past research.

**Analysis)** 

Ministry of Health.

**4.2.4 Bandolier** 

Detailed tables and diagrams information is available at http://www.Prisma-statement.org.

Main differences between QUOROM (Quality Of Reporting Of Meta-analysis) and PRISMA arethe relating to:


#### **4.2.6 EQUATOR Network (Enhancing the QUality and transparency Of Health Research) (Altman & Simera, 2008)**

Is a network of resource development aimed at improving the quality of publications in health sciences, this has provided assistance through its website ( http://www.equatornetwork.org/) that allow a single researcher as well as groups, teach design guidelines for developing quality and transparency. (Liberati A, 2009)

#### **4.2.7 CONSORT declaration (Consolidated Standards of Reporting Trials)**

This led to clinical trials improve quality methodology and resources publication as CONSORT statement, 25 items checklist set of recommendations and a flow diagram development progress.

Objetives are to assist preparation, transparency, critical review and interpretation of Randomized Controlled Trials (RCT).

The first version of 2001 has been revised and perfected in 2010 and includes on its website (http://www.consort-statement.org/) additional resources such as CONSORT "Explanation and Elaboration" document and CONSORT Library of examples of good reporting.

Pureed both access to Downloads, Evidence Database, Glossary, Related Instruments, and link to Useful sites as for example EQUATOR

Members of CONSORT Group continually monitoring literature. Information gleaned from these efforts provides an evidence base on which to update CONSORT statement. We add, drop, or modify items based on that evidence and recommendations of "CONSORT Group", an international and eclectic group of clinical reserarchers, epidemiologists, statisticians, and biomedical editors. More than 400 journals, published around the world and in many

The Treatment of Low Back Pain and Scientific Evidence 45

**Applicability** (items 19-21) refers to the possible implications of the implementation of the

**Editorial independence** (items 22-23) has to do with the independence of the recommendations and the recognition of the potential conflicts of interest by the group.

At the present time there is only another validated scale which assesses the quality of the GPC (Shaneyfelt TM, 1999), but a comparative study between these two instruments (Rich R, 2004) shows that the instrument AGREE, as well as being that in this moment has greater acceptance and provides a more manageable format, manages to make a grouping of criteria more clearly and fully**.** In recent years he has tried to improve the validity of this instrument and value items that better assess the quality of a guide; as a result is the development of the

The fundamental steps to be taken in the development process include the sections described as selection of the topic to research, defining the scope of the review of existing scientific evidence and the process of development, revision, and approval of the recommendations. Furthermore today should be added others relating to the integrity of the members of the research team, transparency and editorial independence, utility, and the

One of the first evidence-based clinical practice guidelines for management of low back pain was published by "The Quebec Task force on spinal Disorders" in 1987.Using an explicit scientific basis found insufficient evidence to support the use of most common diagnostic

The U.S. Agency for Health Care and Policy Research (AHCPR) convened a multidisciplinary panel of experts issued recommendations on management of Acute Low Back Pain (LBP) in 1994, however none of the 40 recommendations made for clinical care were viewed as support by strong research evidence, and only 6 by at least moderate

More than eleven international guidelines have been published since 1994, but their diagnostic and therapeutic recommendations are similar. Only there are few discrepancies to recommendations for exercise, spinal manipulation, muscle relaxants and patient information that reflect contextual differences between countries without signification.

The most interesting from a methodologic point of view are the U.S. Guideline issued by the Veterans Affairs/Department of Defense (VA/DoD) in 1999, the Guideline of Royal College of General Practicioners (RCGP) initially released in 1996 and updated in 1999 , and the

The European Multinational COST B 13 program was developed by The European Commission Directorate General Research Political Co-Ordination and Strategy branch under the title "Low Back Pain: Guidelines for its management". Since 1999 to 2005 were

guidance on organizational aspects, behavior and costs.

II AGREE to replace the original version (AGREE, 2009).

**4.3.1 Previous guidelines and state of the question** 

procedures and treatment modalities.

European COST B 13 Guidelines.

costs.

quality.

**4.3 Recommendations for the process of research development**

languages, have explicitly supported CONSORT statement. However, there is a significant limitation based on this instrument orientation, which is limited to two-group, parallel randomized, controlled trials (RCT) .The items should elicit clear pronouncements of how and what authors did, but do not contain any judgments on how and what authors should have donate. Moreover, CONSORT 2010 Statement does not include recommendations for designing and conducting randomized trials (Schulz K 2010).

#### **4.2.8 AGREE instrument (Appraisal of Guidelines Research and Evaluation in Europe)**

Defines European criteria standards for preparation clinical practice guidelines (GPC). Is available for researchers in http://www.agreecollaboration.org. Assesses both, Information of quality of document provided and some aspects of recommendations. Provides validity guide. Means quality clinical practice guideline confidence that potential biases of the development of the guide have been identified in an appropriate manner and that recommendations are valid both internally and externally, and can lead to practice. Designed to evaluate guidelines developed by local, regional, national or international groups as governmental organizations. Applicable to published guides in paper and electronic format. AGREE consists of 23 key items organized in six areas. Each area tries to cover a dimension differentiated quality of the Guide:

#### **Domains of AGREE Appraisal Instrument II**


Table 3. Appraisal of Guidelines Research and Evaluation in Europe Instrument AGREE II

**Aims and scope** (items 1-3) refers to the overall purpose of the Guide to clinical specific questions and target patient population.

**Participation of those involved** (items 4-7) refers to the degree in which the Guide represents the views of users to which it is intended.

Rigor in drawing up (items 8-14) refers to the process used to gather and synthesize evidence, to formulate recommendations and methods for updating them.

**Clarity and presentation** (items 15-18) deals with the language and format of the Guide.

languages, have explicitly supported CONSORT statement. However, there is a significant limitation based on this instrument orientation, which is limited to two-group, parallel randomized, controlled trials (RCT) .The items should elicit clear pronouncements of how and what authors did, but do not contain any judgments on how and what authors should have donate. Moreover, CONSORT 2010 Statement does not include recommendations for

**4.2.8 AGREE instrument (Appraisal of Guidelines Research and Evaluation in Europe)**  Defines European criteria standards for preparation clinical practice guidelines (GPC). Is available for researchers in http://www.agreecollaboration.org. Assesses both, Information of quality of document provided and some aspects of recommendations. Provides validity guide. Means quality clinical practice guideline confidence that potential biases of the development of the guide have been identified in an appropriate manner and that recommendations are valid both internally and externally, and can lead to practice. Designed to evaluate guidelines developed by local, regional, national or international groups as governmental organizations. Applicable to published guides in paper and electronic format. AGREE consists of 23 key items organized in six areas. Each area tries to

**Domains of AGREE Appraisal Instrument II Scope & Purpose (1,2,3)** objective, health question and population specifically

**Stakeholder involvement (4,5,6**) Relevant professional groups, Views and

 **Rigour of Development (7-14)** Systematic search, Criteria, strenghs and limitations, metods of formulating recommendations, health benefits, side effects and risks, explicit link beetwin recommendation and evidences, Externally

**Clarity of Presentation (15-17)** Recommendations specific / ambiguous, different

**Applicability (18-21)** describe barriers/facilitators, Advices/Tools to put in

**Editorial Independence (22, 23)** Not influence of Publisher, Conflicts of interest

Table 3. Appraisal of Guidelines Research and Evaluation in Europe Instrument AGREE II

**Aims and scope** (items 1-3) refers to the overall purpose of the Guide to clinical specific

**Participation of those involved** (items 4-7) refers to the degree in which the Guide

Rigor in drawing up (items 8-14) refers to the process used to gather and synthesize

**Clarity and presentation** (items 15-18) deals with the language and format of the Guide.

preferences of the target population, Target users defined.

management options, Key recommendations identifiable.

evidence, to formulate recommendations and methods for updating them.

practice, Potential resource implications, Monitoring / Auditing.

reviewed by experts, procedure updating provided.

designing and conducting randomized trials (Schulz K 2010).

cover a dimension differentiated quality of the Guide:

described.

group members.

questions and target patient population.

represents the views of users to which it is intended.

**Applicability** (items 19-21) refers to the possible implications of the implementation of the guidance on organizational aspects, behavior and costs.

**Editorial independence** (items 22-23) has to do with the independence of the recommendations and the recognition of the potential conflicts of interest by the group.

At the present time there is only another validated scale which assesses the quality of the GPC (Shaneyfelt TM, 1999), but a comparative study between these two instruments (Rich R, 2004) shows that the instrument AGREE, as well as being that in this moment has greater acceptance and provides a more manageable format, manages to make a grouping of criteria more clearly and fully**.** In recent years he has tried to improve the validity of this instrument and value items that better assess the quality of a guide; as a result is the development of the II AGREE to replace the original version (AGREE, 2009).

#### **4.3 Recommendations for the process of research development**

The fundamental steps to be taken in the development process include the sections described as selection of the topic to research, defining the scope of the review of existing scientific evidence and the process of development, revision, and approval of the recommendations. Furthermore today should be added others relating to the integrity of the members of the research team, transparency and editorial independence, utility, and the costs.

#### **4.3.1 Previous guidelines and state of the question**

One of the first evidence-based clinical practice guidelines for management of low back pain was published by "The Quebec Task force on spinal Disorders" in 1987.Using an explicit scientific basis found insufficient evidence to support the use of most common diagnostic procedures and treatment modalities.

The U.S. Agency for Health Care and Policy Research (AHCPR) convened a multidisciplinary panel of experts issued recommendations on management of Acute Low Back Pain (LBP) in 1994, however none of the 40 recommendations made for clinical care were viewed as support by strong research evidence, and only 6 by at least moderate quality.

More than eleven international guidelines have been published since 1994, but their diagnostic and therapeutic recommendations are similar. Only there are few discrepancies to recommendations for exercise, spinal manipulation, muscle relaxants and patient information that reflect contextual differences between countries without signification.

The most interesting from a methodologic point of view are the U.S. Guideline issued by the Veterans Affairs/Department of Defense (VA/DoD) in 1999, the Guideline of Royal College of General Practicioners (RCGP) initially released in 1996 and updated in 1999 , and the European COST B 13 Guidelines.

The European Multinational COST B 13 program was developed by The European Commission Directorate General Research Political Co-Ordination and Strategy branch under the title "Low Back Pain: Guidelines for its management". Since 1999 to 2005 were

The Treatment of Low Back Pain and Scientific Evidence 47

Quality of evidence were evaluated using the AHCPR Guide and "The Levels of Evidence" recommended for The Back Group of Cochrane Collaboration (van Tulder 2003). Evidence reviews provide information about whether the studies included are reliable and accurate and provide reasonable assessments of potential adverse effects, information on systematic

The evidence reviews also go through a statistical peer-review process to staticians during

A three-stage development process was undertaken. First, recommendations were derived from systematic reviews. Secondly, existing national guidelines were compared and recommendations from these guidelines summarised. Thirdly, the recommendations from the systematic (Cochrane) reviews and guidelines were discussed by the group. A section was added to the guidelines in which the main points of debate are described. The recommendations are put in a clinically relevant order; recommendations regarding diagnosis have a letter D, treatment T. A grading system was used for the strength of the evidence. This grading system is simple and easy to apply, and shows a large degree of consistency between the grading of therapeutic and preventive, prognostic and diagnostic studies. The system is based on the original ratings of the AHCPR Guidelines (1994) and levels of evidence recommended in the method guidelines of the Cochrane Back Review group. Several of the existing systematic reviews have included non-English language literature, usually publications in French, German, and Dutch language and sometimes also Danish, Norwegian, Finnish and Swedish. All existing national guidelines included studies published in their own language. Consequently, the non-English literature is covered for

The group additionally included the Spanish literature, because this evidence was not

The Working Group aimed to identify gaps in the literature and included recommendations

A grading system was used for the strength of the evidence. This grading system is simple and easy to apply, and shows a large degree of consistency between the grading of therapeutic and preventive, prognostic and diagnostic studies. The system is based on the original ratings of the AHCPR Guidelines (1994) and levels of evidence used in systematic

Generally consistent findings provided by (a systematic review of) multiple high quality

gaps particularly with respect to areas of clinical importance or relevance.

Statistical Review.

its early stages of development.

countries that already have developed guidelines.

**4.3.3 Methodological quality of studies and levels of evidence** 

covered by existing reviews and guidelines.

(Cochrane) reviews on low back pain.

randomised controlled trials (RCTs).

1. Therapy and prevention:

for future research.

**Level of evidence:** 

Level A:

reviewed 74 clinical practice guidelines and 871 Systematic Reviews, Randomized control trials (RCT´) and Prevention studies. Involving a total of 49 experts including Epidemiologists, Public Health, Chiropractors, Psychologists, Physiotherapists, Ergonomists, Physiologists, and Medical Specialists (Primary Care, Anesthesiology, Pain Terapy, Rheumatology, Traumatology, Neurosurgery, Pathology, Rehabilitation, Radiology, Sports Medicine, Emergency Medicine and Occupational Medicine.). The main difference with previous guides is that COST B13 Guide includes recommendations for management Acute, Chronic and prevention of LBP.

In 2009 the American Pain society (APS) has issued a new clinical practice guideline that emphasizes the use of non-invasive treatments over interventional procedures, published of the journal *Spine.* Based on a extensive review of existing research , this review 913 citations for systematic reviews, 265 full text articles for inclusion, of those 186 met inclusion criteria. Identifies 7591 citations from 44 searches for primary studies , from these, 202 primary studies were relevant. For Interventional Therapies and surgery a total of 1331 citations.

However controversy is served because reaffirm previous recommendations (see COST B13 Guide) that avoid invasive therapies and showing benefits of non-invasive (stay active, intensive rehabilitation and cognitive/behavioural emphasis). In contrast the American Society of Interventional Pain Physicians has been published a critical review of Interventional Techniques for chronic and acute LBP (2010) that differs from APS Guidelines including caudal epidural injections, lumbar facet joint nerve blocks, radiofrequency neurotomy, and percutaneous adhesiolysis as appropriate methodology.

Probably better designed studies obtain a balance between non-invasive and interventional therapies.

#### **4.3.2 Key points of systematic reviews and LBP**

A systematic review is a complex process, but we want to emphasize the fundamental aspects of methodology.

1. Selection of Topics

Choosing a topic is the first step in development process. We must consider the following criteria: effect of condition on morbidity , mortality , prevalence of back pain , areas of uncertainty evidence , cost, relevance and availability of developed recommendations.

2. Scope of Topics

Address screening , diagnosis and treatment of back pain focus on the effectiveness of interventions , cost and cost-effectiveness.

3. Review of Evidence for Clinical Recommendations

Evaluating Evidence.

The key questions and scope for the evidence–review papers are developed from the Clinical Guidelines Committee. The evidence review paper is a comprehensive systematic review of meta-analysis that address to management of back pain. Specifies the criteria that are used to identify evidence related to each the key questions for inclusion in the review. Quality of evidence were evaluated using the AHCPR Guide and "The Levels of Evidence" recommended for The Back Group of Cochrane Collaboration (van Tulder 2003). Evidence reviews provide information about whether the studies included are reliable and accurate and provide reasonable assessments of potential adverse effects, information on systematic gaps particularly with respect to areas of clinical importance or relevance.

Statistical Review.

46 Low Back Pain

reviewed 74 clinical practice guidelines and 871 Systematic Reviews, Randomized control trials (RCT´) and Prevention studies. Involving a total of 49 experts including Epidemiologists, Public Health, Chiropractors, Psychologists, Physiotherapists, Ergonomists, Physiologists, and Medical Specialists (Primary Care, Anesthesiology, Pain Terapy, Rheumatology, Traumatology, Neurosurgery, Pathology, Rehabilitation, Radiology, Sports Medicine, Emergency Medicine and Occupational Medicine.). The main difference with previous guides is that COST B13 Guide includes recommendations for management

In 2009 the American Pain society (APS) has issued a new clinical practice guideline that emphasizes the use of non-invasive treatments over interventional procedures, published of the journal *Spine.* Based on a extensive review of existing research , this review 913 citations for systematic reviews, 265 full text articles for inclusion, of those 186 met inclusion criteria. Identifies 7591 citations from 44 searches for primary studies , from these, 202 primary studies were relevant. For Interventional Therapies and surgery a total of 1331 citations.

However controversy is served because reaffirm previous recommendations (see COST B13 Guide) that avoid invasive therapies and showing benefits of non-invasive (stay active, intensive rehabilitation and cognitive/behavioural emphasis). In contrast the American Society of Interventional Pain Physicians has been published a critical review of Interventional Techniques for chronic and acute LBP (2010) that differs from APS Guidelines including caudal epidural injections, lumbar facet joint nerve blocks, radiofrequency

Probably better designed studies obtain a balance between non-invasive and interventional

A systematic review is a complex process, but we want to emphasize the fundamental

Choosing a topic is the first step in development process. We must consider the following criteria: effect of condition on morbidity , mortality , prevalence of back pain , areas of uncertainty evidence , cost, relevance and availability of developed recommendations.

Address screening , diagnosis and treatment of back pain focus on the effectiveness of

The key questions and scope for the evidence–review papers are developed from the Clinical Guidelines Committee. The evidence review paper is a comprehensive systematic review of meta-analysis that address to management of back pain. Specifies the criteria that are used to identify evidence related to each the key questions for inclusion in the review.

neurotomy, and percutaneous adhesiolysis as appropriate methodology.

**4.3.2 Key points of systematic reviews and LBP** 

interventions , cost and cost-effectiveness.

3. Review of Evidence for Clinical Recommendations

Acute, Chronic and prevention of LBP.

therapies.

aspects of methodology. 1. Selection of Topics

2. Scope of Topics

Evaluating Evidence.

The evidence reviews also go through a statistical peer-review process to staticians during its early stages of development.

A three-stage development process was undertaken. First, recommendations were derived from systematic reviews. Secondly, existing national guidelines were compared and recommendations from these guidelines summarised. Thirdly, the recommendations from the systematic (Cochrane) reviews and guidelines were discussed by the group. A section was added to the guidelines in which the main points of debate are described. The recommendations are put in a clinically relevant order; recommendations regarding diagnosis have a letter D, treatment T. A grading system was used for the strength of the evidence. This grading system is simple and easy to apply, and shows a large degree of consistency between the grading of therapeutic and preventive, prognostic and diagnostic studies. The system is based on the original ratings of the AHCPR Guidelines (1994) and levels of evidence recommended in the method guidelines of the Cochrane Back Review group. Several of the existing systematic reviews have included non-English language literature, usually publications in French, German, and Dutch language and sometimes also Danish, Norwegian, Finnish and Swedish. All existing national guidelines included studies published in their own language. Consequently, the non-English literature is covered for countries that already have developed guidelines.

The group additionally included the Spanish literature, because this evidence was not covered by existing reviews and guidelines.

The Working Group aimed to identify gaps in the literature and included recommendations for future research.

#### **4.3.3 Methodological quality of studies and levels of evidence**

A grading system was used for the strength of the evidence. This grading system is simple and easy to apply, and shows a large degree of consistency between the grading of therapeutic and preventive, prognostic and diagnostic studies. The system is based on the original ratings of the AHCPR Guidelines (1994) and levels of evidence used in systematic (Cochrane) reviews on low back pain.

#### **Level of evidence:**

1. Therapy and prevention:

Level A:

Generally consistent findings provided by (a systematic review of) multiple high quality randomised controlled trials (RCTs).

The Treatment of Low Back Pain and Scientific Evidence 49

High quality diagnostic study: Independent blind comparison of patients from an appropriate spectrum of patients, all of whom have undergone both the diagnostic test and the reference standard. (An appropriate spectrum is a cohort of patients who would normally be tested for the target disorder. An inappropriate spectrum compares patients already known to have the target disorder with patients diagnosed with another condition) Low quality diagnostic study: Study performed in a set of non-consecutive patients, or confined to a narrow spectrum of study individuals (or both) all of who have undergone both the diagnostic test and the reference standard, or if the reference standard was unobjective, unblinded or not independent, or if positive and negative tests were verified using separate reference standards, or if the study was performed in an inappropriate spectrum of patients, or if the reference standard was not applied to all study patients.

The methodological quality of additional studies will only be assessed in areas that have not

The methodological quality of trials is usually assessed using relevant criteria related to the internal validity of trials. High quality trials are less likely to be associated with biased results than low quality trials. Various criteria lists exist, but differences between the lists are

Quality assessment should ideally be done by at least two reviewers, independently, and

However, as experts are usually involved in quality assessment it may often not be feasible to blind studies. Criteria should be scored as positive, negative or unclear, and it should be clearly defined when criteria are scored positive or negative. Quality assessment should be pilot tested on two or more similar trials that are not included in the systematic review. A consensus method should be used to resolve disagreements and a third reviewer was consulted if disagreements persisted. If the article does not contain information on the methodological criteria (score 'unclear'), the authors should be contacted for additional information. This also gives authors the opportunity to respond to negative or positive

been covered yet by a systematic review or of the non-English literature.

blinded with regard to the authors, institution and journal.

The following checklists are recommended:

**4.3.4 Checklist for methodological quality** 

1. Adequate method of randomisation, 2. Concealment of treatment allocation,

4. Co-interventions avoided or equal,

5. Blinding of patients, 6. Blinding of observer,

**Checklist for methodological quality of therapy / prevention studies** 

3. Withdrawal / drop-out rate described and acceptable,

Level D, no evidence: No diagnostic studies.

subtle.

scores.

Items:

Level B:

Generally consistent findings provided by (a systematic review of) multiple low quality RCTs or non-randomised controlled trials (CCTs).

Level C:

One RCT (either high or low quality) or inconsistent findings from (a systematic review of) multiple RCTs or CCTs.

Level D:

No RCTs or CCTs.

Systematic review: systematic methods of selection and inclusion of studies, methodological quality assessment, data extraction and analysis.

2. Prognosis:

Level A:

Generally consistent findings provided by (a systematic review of) multiple high quality prospective cohort studies.

Level B:

Generally consistent findings provided by (a systematic review of) multiple low quality prospective cohort studies or other low quality prognostic studies.

Level C:

One prognostic study (either high or low quality) or inconsistent findings from (a systematic review of) multiple prognostic studies.

Level D, no evidence:

No prognostic studies.

High quality prognostic studies: prospective cohort studies Low quality prognostic studies: retrospective cohort studies, follow-up of untreated control patients in a RCT, case-series

3. Diagnosis:

Level A:

Generally consistent findings provided by (a systematic review of) multiple high quality diagnostic studies.

Level B:

Generally consistent findings provided by (a systematic review of) multiple low quality diagnostic studies.

Level C:

One diagnostic study (either high or low quality) or inconsistent findings from (a systematic review of) multiple diagnostic studies.

Level D, no evidence:

48 Low Back Pain

Generally consistent findings provided by (a systematic review of) multiple low quality

One RCT (either high or low quality) or inconsistent findings from (a systematic review of)

Systematic review: systematic methods of selection and inclusion of studies, methodological

Generally consistent findings provided by (a systematic review of) multiple high quality

Generally consistent findings provided by (a systematic review of) multiple low quality

One prognostic study (either high or low quality) or inconsistent findings from (a systematic

High quality prognostic studies: prospective cohort studies Low quality prognostic studies: retrospective cohort studies, follow-up of untreated control patients in a RCT, case-series

Generally consistent findings provided by (a systematic review of) multiple high quality

Generally consistent findings provided by (a systematic review of) multiple low quality

One diagnostic study (either high or low quality) or inconsistent findings from (a systematic

prospective cohort studies or other low quality prognostic studies.

RCTs or non-randomised controlled trials (CCTs).

quality assessment, data extraction and analysis.

Level B:

Level C:

Level D:

Level A:

Level B:

Level C:

multiple RCTs or CCTs.

prospective cohort studies.

Level D, no evidence: No prognostic studies.

3. Diagnosis:

diagnostic studies.

diagnostic studies.

Level A:

Level B:

Level C:

review of) multiple prognostic studies.

review of) multiple diagnostic studies.

No RCTs or CCTs.

2. Prognosis:

No diagnostic studies.

High quality diagnostic study: Independent blind comparison of patients from an appropriate spectrum of patients, all of whom have undergone both the diagnostic test and the reference standard. (An appropriate spectrum is a cohort of patients who would normally be tested for the target disorder. An inappropriate spectrum compares patients already known to have the target disorder with patients diagnosed with another condition) Low quality diagnostic study: Study performed in a set of non-consecutive patients, or confined to a narrow spectrum of study individuals (or both) all of who have undergone both the diagnostic test and the reference standard, or if the reference standard was unobjective, unblinded or not independent, or if positive and negative tests were verified using separate reference standards, or if the study was performed in an inappropriate spectrum of patients, or if the reference standard was not applied to all study patients.

The methodological quality of additional studies will only be assessed in areas that have not been covered yet by a systematic review or of the non-English literature.

The methodological quality of trials is usually assessed using relevant criteria related to the internal validity of trials. High quality trials are less likely to be associated with biased results than low quality trials. Various criteria lists exist, but differences between the lists are subtle.

Quality assessment should ideally be done by at least two reviewers, independently, and blinded with regard to the authors, institution and journal.

However, as experts are usually involved in quality assessment it may often not be feasible to blind studies. Criteria should be scored as positive, negative or unclear, and it should be clearly defined when criteria are scored positive or negative. Quality assessment should be pilot tested on two or more similar trials that are not included in the systematic review. A consensus method should be used to resolve disagreements and a third reviewer was consulted if disagreements persisted. If the article does not contain information on the methodological criteria (score 'unclear'), the authors should be contacted for additional information. This also gives authors the opportunity to respond to negative or positive scores.

The following checklists are recommended:

#### **4.3.4 Checklist for methodological quality**

#### **Checklist for methodological quality of therapy / prevention studies**

Items:


The Treatment of Low Back Pain and Scientific Evidence 51

Authors of German-speaking countries in Europe were more likely to publish RCTs in an English-language journal if the results were statistically significant. On the other hand, Moher et al. (1996) evaluated the quality of reporting of RCTs published in English, French, German, Italian and Spanish between 1989 and 1993 and did not find significant differences. Trials published in some non-English languages (Chinese, Japanese, Russian and

Excluding trials published in other languages than English generally has little impact on the

Although the evidence seems to be inconclusive, most authors concluded that all trials should be included in a systematic review regardless of the language in which they were published, to increase precision and reduce bias. The Cochrane Back Review Group recommended in its method guidelines for reviews on low back pain that if RCTs published in other languages are excluded from a review, the reason for this decision should be given. (van Tulder et al 2003) Especially on topics where there are likely to be a significant number of non-English language publications (for example, the Asian literature on acupuncture) it may be wise to consider involvement of a collaborator with relevant language skills. The members of the Working Group acknowledged that a different literature search should be performed for non-English literature than for the English literature. Databases do not exist for most other languages, the reliability and coverage of the databases that do exist is unclear, and sensitive search strategies for these databases may not have been developed.

Most of the systematic reviews used in the European guidelines included trials published in English and some other languages (mostly German, French, Dutch and sometimes Swedish, Danish, Norwegian and Finnish). Obviously, the national guidelines that we have used as basis for our recommendations have included studies published in their respective languages. National committees that developed guidelines in these languages have considered Danish, Dutch, Finnish, French, German, Norwegian and Swedish language studies. Only Italian and Spanish trials have yet not been considered, because guidelines in

Because there was no Italian member participating in the WG, we only considered the

To summarise the evidence from the Spanish literature and evaluate if it supports the

Relevant trials were identified in existing databases: Literatura Latino Americana e do Caribe em Ciencias da Saude (LILACS) and Índice Médico Español (IME). The Iberoamerican Cochrane Centre (Centro Iberoamericano de la Colaboración Cochrane ) was

Inclusion criteria are: 1) randomised controlled trials, 2) acute and subacute low back pain

evidence review and recommendations of the guidelines.

Taiwanese) had an unusually high proportion of positive results.

overall treatment effect.

these countries do not exist.

Spanish literature.

**Literature search** 

contacted for additional trials.

(less than 12 weeks), and 3) any intervention.

**Objectives** 

**Methods** 


#### **Checklist for methodological quality of prognosis (observational) studies**

Items:


#### **Checklist for methodological quality of diagnostic studies**

Items:


#### **4.3.5 Inclusion of non-English language literature**

#### **Background**

There is still an ongoing debate about inclusion in systematic reviews of studies published in other languages than English. Although inclusion of non-English literature is often recommended, it may not always be feasible and may depend on the time and resources available. Some authors suggested that there is empirical evidence that exclusion of trials published in other languages than English might be associated with bias. Positive results by authors from non-English speaking countries are more likely to be published in English and negative results in the authors' language. They found an example of a metaanalysis where inclusion of a non-English language trial changed the results and conclusion.

4. Were the interpretations of the index test and reference test performed independently

5. Was the choice of patients who were assessed by the reference test independent of the

6. When different index tests are compared in the study: were the index tests compared in

9. Were data adequately presented in enough detail to calculate test characteristics

There is still an ongoing debate about inclusion in systematic reviews of studies published in other languages than English. Although inclusion of non-English literature is often recommended, it may not always be feasible and may depend on the time and resources available. Some authors suggested that there is empirical evidence that exclusion of trials published in other languages than English might be associated with bias. Positive results by authors from non-English speaking countries are more likely to be published in English and negative results in the authors' language. They found an example of a metaanalysis where inclusion of a non-English language trial changed the results and

**Checklist for methodological quality of prognosis (observational) studies** 

7. Blinding of care provider 8. Intention-to-treat analysis,

4. Prospective study design,

10. Similarity of baseline characteristics.

1. Adequate selection of study population, 2. Description of in- and exclusion criteria, 3. Description of potential prognostic factors,

5. Adequate study size (> 100 patient-years), 6. Adequate follow-up (> 12 months), 7. Adequate loss to follow-up (< 20%), 8. Relevant outcome measures, 9. Appropriate statistical analysis.

1. Was at least one valid reference test used?

**Checklist for methodological quality of diagnostic studies** 

2. Was the reference test applied in a standardised manner? 3. Was each patient submitted to at least one valid reference test?

8. Was a description included regarding missing data?

**4.3.5 Inclusion of non-English language literature** 

9. Compliance,

Items:

Items:

of each other?

a valid design?

**Background** 

conclusion.

results of the index test?

7. Was the study design prospective?

(sensitivity and specificity)?

Authors of German-speaking countries in Europe were more likely to publish RCTs in an English-language journal if the results were statistically significant. On the other hand, Moher et al. (1996) evaluated the quality of reporting of RCTs published in English, French, German, Italian and Spanish between 1989 and 1993 and did not find significant differences. Trials published in some non-English languages (Chinese, Japanese, Russian and Taiwanese) had an unusually high proportion of positive results.

Excluding trials published in other languages than English generally has little impact on the overall treatment effect.

Although the evidence seems to be inconclusive, most authors concluded that all trials should be included in a systematic review regardless of the language in which they were published, to increase precision and reduce bias. The Cochrane Back Review Group recommended in its method guidelines for reviews on low back pain that if RCTs published in other languages are excluded from a review, the reason for this decision should be given. (van Tulder et al 2003) Especially on topics where there are likely to be a significant number of non-English language publications (for example, the Asian literature on acupuncture) it may be wise to consider involvement of a collaborator with relevant language skills. The members of the Working Group acknowledged that a different literature search should be performed for non-English literature than for the English literature. Databases do not exist for most other languages, the reliability and coverage of the databases that do exist is unclear, and sensitive search strategies for these databases may not have been developed.

Most of the systematic reviews used in the European guidelines included trials published in English and some other languages (mostly German, French, Dutch and sometimes Swedish, Danish, Norwegian and Finnish). Obviously, the national guidelines that we have used as basis for our recommendations have included studies published in their respective languages. National committees that developed guidelines in these languages have considered Danish, Dutch, Finnish, French, German, Norwegian and Swedish language studies. Only Italian and Spanish trials have yet not been considered, because guidelines in these countries do not exist.

Because there was no Italian member participating in the WG, we only considered the Spanish literature.

#### **Objectives**

To summarise the evidence from the Spanish literature and evaluate if it supports the evidence review and recommendations of the guidelines.

#### **Methods**

#### **Literature search**

Relevant trials were identified in existing databases: Literatura Latino Americana e do Caribe em Ciencias da Saude (LILACS) and Índice Médico Español (IME). The Iberoamerican Cochrane Centre (Centro Iberoamericano de la Colaboración Cochrane ) was contacted for additional trials.

Inclusion criteria are: 1) randomised controlled trials, 2) acute and subacute low back pain (less than 12 weeks), and 3) any intervention.

The Treatment of Low Back Pain and Scientific Evidence 53





A successful implementation of guidelines requires thoroughly performed planning and monitoring of the implementation whereof addressing barriers and facilitators appear to be of vital importance to enhance the implementation process. Before starting the implementation such barriers and facilitators should be systematically recorded among

Practice organisation, e.g. lack of disease registers or mechanisms to monitor repeat

Inappropriate continuing education and failure to link up with programmes to promote

Lack of incentives to participate in effective educational activities



specific information was sought from or given to patients.

Educational outreach visits (for prescribing in North American settings)

*Consistently effective are* 

Audit and feedback

Local opinion leaders

appropriate.



Local consensus process

Patient mediated interventions

Didactic educational meetings

**4.4.1 Barriers and facilitators** 

**Practice environment**  Limitations of time

prescribing.

**Educational environment** 

quality of care

target groups for applying the clinical guidelines.

Potential barriers to change may include:

*Mixed effects* 

Multifaceted interventions

Interactive educational meetings

Reminders (manual or computerised)


reminders, local consensus process and marketing

#### **Quality Appraisal**

The abstracts with no English version have been translated from Spanish by a native English speaker. Some papers had an English version of their abstracts. In these cases, the translator has just done a linguistic review of them and, in those cases in which the Spanish and English versions did not match, a translation of the Spanish abstract has been done. Some Spanish journals publish only short reports of the studies (similar to abstracts). In these cases, the entire report has been considered as the abstract. Other Spanish journals have a mandatory structure for the abstracts they publish, which may have changed over time, but most do not. Therefore, there is a considerable difference in the amount of information provided by different abstracts.

Two reviewers assessed the quality of the trials using the checklist for methodological quality of therapy/prevention studies.

#### **Data extraction**

Data were extracted regarding characteristics of patients, interventions and outcomes (pain, functional status, global improvement, return to work, patient satisfaction, quality of life, generic functional status and intervention-specific outcomes) and the final results of the study for each outcome measure at each follow-up moment.

#### **Data analysis**

The results of the Spanish literature (quality, data and results) were considered by the members of the WG to see if the results do or do not support the recommendations. If not, reasons for these inconsistencies were explored.

#### **4.4 Dissemination and implementation**

Clinical guidelines are usually defined as 'systematically developed statements to assist practitioner and patient decisions about appropriate health care' as a vehicle for assisting health care providers in grasping new evidence and bring it into daily clinical routines for improving practice and for diminishing costs.

Implementation of guidelines means putting something (e.g. a plan or an innovation) into use. The process of spreading clinical guidelines implies diffusion, active dissemination and implementation. Diffusion is a passive concept while dissemination is a more active process including launching of targeted and tailored information for the intended audience. Implementation often involves identifying and assisting in overcoming barriers to the use of the knowledge obtained from a tailored message.

Normally implementation procedures mean a multi-disciplinary enterprise.

#### **Effectiveness of interventions**

Success in the implementation process requires knowledge about important factors behind general positive and negative attitudes towards guidelines related to usefulness, reliability, practicality and availability of the guidelines. Also the overall individual, team and organisational competence to follow recommended procedures seem to be vital.

Systematic reviews of the effectiveness of interventions to promote professional behaviour or change have shown:

#### *Consistently effective are*


#### *Mixed effects*

52 Low Back Pain

The abstracts with no English version have been translated from Spanish by a native English speaker. Some papers had an English version of their abstracts. In these cases, the translator has just done a linguistic review of them and, in those cases in which the Spanish and English versions did not match, a translation of the Spanish abstract has been done. Some Spanish journals publish only short reports of the studies (similar to abstracts). In these cases, the entire report has been considered as the abstract. Other Spanish journals have a mandatory structure for the abstracts they publish, which may have changed over time, but most do not. Therefore, there is a considerable difference in the amount of information

Two reviewers assessed the quality of the trials using the checklist for methodological

Data were extracted regarding characteristics of patients, interventions and outcomes (pain, functional status, global improvement, return to work, patient satisfaction, quality of life, generic functional status and intervention-specific outcomes) and the final results of the

The results of the Spanish literature (quality, data and results) were considered by the members of the WG to see if the results do or do not support the recommendations. If not,

Clinical guidelines are usually defined as 'systematically developed statements to assist practitioner and patient decisions about appropriate health care' as a vehicle for assisting health care providers in grasping new evidence and bring it into daily clinical routines for

Implementation of guidelines means putting something (e.g. a plan or an innovation) into use. The process of spreading clinical guidelines implies diffusion, active dissemination and implementation. Diffusion is a passive concept while dissemination is a more active process including launching of targeted and tailored information for the intended audience. Implementation often involves identifying and assisting in overcoming barriers to the use of

Success in the implementation process requires knowledge about important factors behind general positive and negative attitudes towards guidelines related to usefulness, reliability, practicality and availability of the guidelines. Also the overall individual, team and

Systematic reviews of the effectiveness of interventions to promote professional behaviour

Normally implementation procedures mean a multi-disciplinary enterprise.

organisational competence to follow recommended procedures seem to be vital.

**Quality Appraisal** 

**Data extraction** 

**Data analysis** 

provided by different abstracts.

quality of therapy/prevention studies.

study for each outcome measure at each follow-up moment.

reasons for these inconsistencies were explored.

**4.4 Dissemination and implementation** 

improving practice and for diminishing costs.

the knowledge obtained from a tailored message.

**Effectiveness of interventions** 

or change have shown:

	- Any intervention aimed at changing the performance of health care providers where specific information was sought from or given to patients.
	- *Little or no effect*

#### **4.4.1 Barriers and facilitators**

A successful implementation of guidelines requires thoroughly performed planning and monitoring of the implementation whereof addressing barriers and facilitators appear to be of vital importance to enhance the implementation process. Before starting the implementation such barriers and facilitators should be systematically recorded among target groups for applying the clinical guidelines.

Potential barriers to change may include:

#### **Practice environment**


#### **Educational environment**


7. Biosis 8. Lilacs

**Search Strategy:** 

9. IME (Índice Médico Español)

#1 (back pain) AND systematic[sb]

Publication Date from 1990, Review 3. **Embase:** #1 Back pain. De (MESH)

4. **Pascal, Psychoinfo and Biosis:** 

5. **Lilacs:** #1 dolor de espalda. [DE]

#2 (lumbago) O lumbalgia. [TI]

#3 (dolor) Y espalda. [TI]

#5 (revisión) Y sistemática.

#3 revisión sistemática

#4 #1 O #2 O #3

#6 #4 Y #5

#2 Low back pain. De (MESH)

#3 1 OR 2

#4 Systematic

#1 Back pain

#3 1 OR 2

#4 Systematic

#2 Low back pain

#2 (back pain) AND systematic[sb] Field: All Fields, Limits:

#3 (back pain) AND systematic[sb] Field: All Fields, Limits:

#5 3 and 4 (Limitado por Review y publicaciones desde 1990)

6. **IME:** #1 (dolor de espalda) O lumbago O lumbalgia. [DE]

#2 (dolor de espalda) O lumbago O lumbalgia 203

#5 3 AND 4 (limit to Publication type"Review" and Publication Date since1990)

1. **Cochrane**: #·1 Back pain. 2. **Medline and Health Star**: **a. sensitive strategy:** 

Publication Date from 1990 **b. specific strategy: Adding:** 

The Treatment of Low Back Pain and Scientific Evidence 55

#### **Health care environment**


#### **Social environment**


#### **Practitioner factors**


#### **Patient factors**


Implementation strategies should be tailored according to recorded identified barriers and facilitators. How to do this is described in detail in *Evidence Based Practice in Primary Care.* 

#### *Evaluation*

In general it is also recommended to evaluate outcome and result of the implementation process. Outcome measures related to low back pain will often be before and after status of use of health services, for instance x-ray, sickness absence and back related health status of the patient population (e.g. pain, function/quality of life). Types of evaluation may include RCTs, cross-over and semi-experimental trials, before-after study and interrupted time series analyses. An economic evaluation is also required on both the course and the benefits of implementation analysis.

Oxman *et al.* reviewed 102 randomised controlled trials in which changes in physician behaviour were attempted through means such as continuing medical education workshops and seminars, educational materials, academic detailing and audit and feedback. Each produced some change but the authors concluded that a multi-faceted strategy was called for using a combination of methods and that there can be no "magic bullet" for a successful implementation.

#### **4.5 Search strategy for the systematic reviews**

#### **Literature search, conducted 11.12.2001**

Databases


7. Biosis

54 Low Back Pain

Beliefs and attitudes (for example, related to previous adverse experience of innovation)

Implementation strategies should be tailored according to recorded identified barriers and facilitators. How to do this is described in detail in *Evidence Based Practice in Primary Care.* 

In general it is also recommended to evaluate outcome and result of the implementation process. Outcome measures related to low back pain will often be before and after status of use of health services, for instance x-ray, sickness absence and back related health status of the patient population (e.g. pain, function/quality of life). Types of evaluation may include RCTs, cross-over and semi-experimental trials, before-after study and interrupted time series analyses. An economic evaluation is also required on both the course and the benefits

Oxman *et al.* reviewed 102 randomised controlled trials in which changes in physician behaviour were attempted through means such as continuing medical education workshops and seminars, educational materials, academic detailing and audit and feedback. Each produced some change but the authors concluded that a multi-faceted strategy was called for using a combination of methods and that there can be no "magic bullet" for a successful

**Health care environment**  Lack of financial resources

**Social environment** 

**Practitioner factors**  Obsolete knowledge

**Patient factors**  Demands for care

*Evaluation* 

Influence of opinion leaders

of implementation analysis.

implementation.

Databases

1. Cochrane 2. Medline 3. Health Star 4. Embase 5. Pascal 6. Psychoinfo

Lack of defined practice populations

 Health policies which promote ineffective or unproven activities Failure to provide practitioners with access to appropriate information

Influence of media on patients in creating demands/beliefs

Impact of disadvantage on patients' access to care

Perceptions/cultural beliefs about appropriate care

**4.5 Search strategy for the systematic reviews** 

**Literature search, conducted 11.12.2001** 


#### **Search Strategy:**


#2 (back pain) AND systematic[sb] Field: All Fields, Limits:

Publication Date from 1990

#### **b. specific strategy: Adding:**

#3 (back pain) AND systematic[sb] Field: All Fields, Limits:

Publication Date from 1990, Review

3. **Embase:** #1 Back pain. De (MESH)

#2 Low back pain. De (MESH)

#3 1 OR 2

#4 Systematic

#5 3 and 4 (Limitado por Review y publicaciones desde 1990)

#### 4. **Pascal, Psychoinfo and Biosis:**

#1 Back pain

#2 Low back pain

#3 1 OR 2

#4 Systematic

#5 3 AND 4 (limit to Publication type"Review" and Publication Date since1990)

5. **Lilacs:** #1 dolor de espalda. [DE]

```
#2 (lumbago) O lumbalgia. [TI]
```

```
#3 (dolor) Y espalda. [TI]
```
#4 #1 O #2 O #3

#5 (revisión) Y sistemática.

#6 #4 Y #5

6. **IME:** #1 (dolor de espalda) O lumbago O lumbalgia. [DE]

#2 (dolor de espalda) O lumbago O lumbalgia 203

#3 revisión sistemática

The Treatment of Low Back Pain and Scientific Evidence 57

\* 20 163 #4 or #5 or #6 or #7 or #8 or #9 or #10 or #11 or #12 or #13 or #14 or

#20 #3 or #4 or #5 or #6 or #7 or #8 or #9 or #10 or #11 or #12 or

#19 interferential therapy and #3 and (PY=1995-2002) (0 records)

#13 or #14 or #15 or #16 or #17 or #18 or #19 (6 records)

#16 diathermy and #3 and (PY=1995-2002) (0 records)

#12 ultrasound and #3 and (PY=1995-2002) (0 records)

#8 manipulation and #3 and (PY=1995-2002) (0 records)

#2 randomized trial and (PY=1995-2002) (352 records)

#1 back pain and (PY=1995-2002) (645 records)

#7 bracing and #3 and (PY=1995-2002) (0 records) #6 traction and #3 and (PY=1995-2002) (0 records) #5 training and #3 and (PY=1995-2002) (0 records) #4 exercise and #3 and (PY=1995-2002) (2 records)

#3 #1 and #2 (6 records)

#15 electrotherapy and #3 and (PY=1995-2002) (0 records) #14 manual therapy and #3 and (PY=1995-2002) (0 records)

#18 TNS and #3 and (PY=1995-2002) (0 records) #17 laser and #3 and (PY=1995-2002) (0 records)

#13 tens and #3 and (PY=1995-2002) (0 records)

#11 cold and #3 and (PY=1995-2002) (0 records) #10 heat and #3 and (PY=1995-2002) (0 records) #9 massage and #3 and (PY=1995-2002) (0 records)

14 0 electrotherapy and #3

17 9 manual therapy and #3

19 1 interferential therapy and #3

#15 or #16 or #17 or #18 or #19

15 3 diathermy and #3

16 4 laser and #3

18 4 TNS and #3

**Psychinfo** 

Search History

#4 #1 Y #3 #5 #2 Y #3 **RESULTS Total hits**  Cochrane 12 Medline and Health Star "Specific": 121 5 excluded 20 redundant "Sensitive" 273 121 redundant with Medline specific 14 excluded 10 redundant Embase 13 1 redundant Pascal, Psychoinfo and Biosis 14 2 redundant Lilacs 0 IME 0 **Typical subgroup search (e.g. results for physical treatments and exercise) Embase**  No. Records Request 1 9163 back pain 2 74295 randomized trial 3 458 #1 and #2 4 81 exercise and #3 5 44 training and #3 6 14 traction and #3 7 0 bracing and #3 8 29 manipulation and #3 9 14 massage and #3 10 8 heat and #3 11 5 cold and #3 12 4 ultrasound and #3 13 7 tens and #3

#4 #1 Y #3 #5 #2 Y #3 **RESULTS Total hits**  Cochrane 12

Medline and Health Star

Embase 13 1 redundant

**Typical subgroup search** 

No. Records Request

2 74295 randomized trial

8 29 manipulation and #3

9 14 massage and #3

12 4 ultrasound and #3

10 8 heat and #3 11 5 cold and #3

13 7 tens and #3

1 9163 back pain

3 458 #1 and #2

4 81 exercise and #3 5 44 training and #3 6 14 traction and #3 7 0 bracing and #3

Medline specific

14 excluded 10 redundant

Lilacs 0 IME 0

**Embase** 

"Specific": 121 5 excluded 20 redundant

Pascal, Psychoinfo and Biosis 14 2 redundant

**(e.g. results for physical treatments and exercise)** 

"Sensitive" 273 121 redundant with

14 0 electrotherapy and #3 15 3 diathermy and #3 16 4 laser and #3 17 9 manual therapy and #3 18 4 TNS and #3 19 1 interferential therapy and #3 \* 20 163 #4 or #5 or #6 or #7 or #8 or #9 or #10 or #11 or #12 or #13 or #14 or #15 or #16 or #17 or #18 or #19 **Psychinfo**  Search History #20 #3 or #4 or #5 or #6 or #7 or #8 or #9 or #10 or #11 or #12 or #13 or #14 or #15 or #16 or #17 or #18 or #19 (6 records) #19 interferential therapy and #3 and (PY=1995-2002) (0 records) #18 TNS and #3 and (PY=1995-2002) (0 records) #17 laser and #3 and (PY=1995-2002) (0 records) #16 diathermy and #3 and (PY=1995-2002) (0 records) #15 electrotherapy and #3 and (PY=1995-2002) (0 records) #14 manual therapy and #3 and (PY=1995-2002) (0 records) #13 tens and #3 and (PY=1995-2002) (0 records) #12 ultrasound and #3 and (PY=1995-2002) (0 records) #11 cold and #3 and (PY=1995-2002) (0 records) #10 heat and #3 and (PY=1995-2002) (0 records) #9 massage and #3 and (PY=1995-2002) (0 records) #8 manipulation and #3 and (PY=1995-2002) (0 records) #7 bracing and #3 and (PY=1995-2002) (0 records) #6 traction and #3 and (PY=1995-2002) (0 records) #5 training and #3 and (PY=1995-2002) (0 records) #4 exercise and #3 and (PY=1995-2002) (2 records) #3 #1 and #2 (6 records) #2 randomized trial and (PY=1995-2002) (352 records) #1 back pain and (PY=1995-2002) (645 records)

The Treatment of Low Back Pain and Scientific Evidence 59

To streamline the work plan were drafting chapters on acute low back pain, chronic and prevention, stratified components in 3 sub-working groups. Finally, in our case was working Spanish Group for improvement and adaptation directed by the Spanish

Search and selection of scientific evidence by means computerized databases and documentary looking time period more comprehensive as possible, with strategies to include those available in languages other than English, particularly in Spanish, but also supplement with contributions of studies which were undergoing investigation or

Explored databases were Cochrane, Medline, Embase, health Star, Pascal, PsycINFO, SPORT

Methodological evidence quality assessment detected in each systematic review and original studies found according to Oxman and Guyatt methodological criteria (annex 2 GPC COST)

Levels of evidence for recommendations arising from number of studies that underlie them, quality methodology and consistency results, according to criteria based on guidance of advice (Bigos1994) and "levels of evidence" recommended by the Cochrane Collaboration

*¨Criterion of "Systematic review": use of systematic methods to select and include studies, assessment of methodological quality and extraction and analysis of data. Are defined as "results consistent to the coincidence in the sense of the results, at least 75% of the studies".\* Studies: diagnostic, prognosis* 

Review and approval content of Guide once analysed available scientific evidence each group developed recommendations and discussion according to a fixed timetable, by electronic means and meetings seeing them joint the overall content of the Guide,

Level A : Results of a systematic¨ review of multiple studies\* (high quality).

*(prospective), treatment (controlled clinical trial), prevention (controlled clinical trial)* 

articulating a mechanism of critical inter groups until approval by unanimity.

Spanish adaptation by the Working Group formed with the aim of:

Level B : Results of a systematic¨ review of studies\* (low quality).

Level C : Results of a single study \* (high or low quality), or inconsistent systematic¨ review of multiple studies.

representatives of European Management Committee.

**5.2 Search and selection of scientific evidence** 

**5.3 Methodological evidence quality assessment** 

**5.4 Levels of evidence for recommendations** 

Level D : Non-obviousness (lack of studies).

**5.5 Review and approval content of Guide** 

**5.6 Spanish adaptation by the Working Group** 

back group (van Tulder 2003). (Table 4)

Table 4. Evidence Levels

publication, but excluding not accepted.

ciscos, Biosis, Lilacs and EMI.

#### **5. Elaboration of a CPG based on scientific evidence. The Spanish version of COST B13 European program**

It is a long and complex process that must be completed by a method of work explained in part previous sections and follows a basic sequence ( figure 3). The systematic reviews were identified using the results of validated search strategies in the Cochrane Library, Medline, Embase and, if relevant, other electronic databases, performed for Clinical Evidence, a monthly, updated directory of evidence on the effects of common clinical interventions, published by the BMJ Publishing Group (www.evidence.org). The literature search covered the period from 1966 to October 2005. A search for clinical guidelines was first performed in Medline. Since guidelines are only infrequently published in medical journals we extended the 5 search on the Internet (using search terms 'back pain' and 'guidelines', and searching national health professional association and consumers websites) and identified guidelines by personal communication with experts in the field.

A three-stage development process was undertaken. First, recommendations were derived from systematic reviews. Secondly, existing national guidelines were compared and recommendations from these guidelines summarised. Thirdly, the recommendations from the systematic (Cochrane) reviews and guidelines were discussed by the group. A section was added to the guidelines in which the main points of debate are described. The recommendations are put in a clinically relevant order; recommendations regarding diagnosis have a letter D, treatment T.

A grading system was used for the strength of the evidence. This grading system is simple and easy to apply, and shows a large degree of consistency between the grading of therapeutic and preventive, prognostic and diagnostic studies. The system is based on the original ratings of the AHCPR Guidelines (1994) and levels of evidence recommended in the method guidelines of the Cochrane Back Review group. The strength of the recommendations was not graded.

Several of the existing systematic reviews have included non-English language literature, usually publications in French, German, and Dutch language and sometimes also Danish, Norwegian, Finnish and Swedish. All existing national guidelines included studies published in their own language. Consequently, the non- English literature is covered for countries that already have developed guidelines.

The group additionally included the Spanish literature, because this evidence was not covered by existing reviews and guidelines.

The Working Group aimed to identify gaps in the literature and included recommendations for future research.

Basic Sequence:

#### **5.1 Constitution of the multidisciplinary working group**

Constitution of the multidisciplinary working group through a Management Committee composed of experts in field of low back pain, appointed by the Governments of 14 countries participating in European Union, framed in the Directorate General Research, Political Co-ordination and Strategy (COST) and B13 program "Low back Pain: Guidelines for its management".

**5. Elaboration of a CPG based on scientific evidence. The Spanish version of** 

It is a long and complex process that must be completed by a method of work explained in part previous sections and follows a basic sequence ( figure 3). The systematic reviews were identified using the results of validated search strategies in the Cochrane Library, Medline, Embase and, if relevant, other electronic databases, performed for Clinical Evidence, a monthly, updated directory of evidence on the effects of common clinical interventions, published by the BMJ Publishing Group (www.evidence.org). The literature search covered the period from 1966 to October 2005. A search for clinical guidelines was first performed in Medline. Since guidelines are only infrequently published in medical journals we extended the 5 search on the Internet (using search terms 'back pain' and 'guidelines', and searching national health professional association and consumers websites) and identified guidelines

A three-stage development process was undertaken. First, recommendations were derived from systematic reviews. Secondly, existing national guidelines were compared and recommendations from these guidelines summarised. Thirdly, the recommendations from the systematic (Cochrane) reviews and guidelines were discussed by the group. A section was added to the guidelines in which the main points of debate are described. The recommendations are put in a clinically relevant order; recommendations regarding

A grading system was used for the strength of the evidence. This grading system is simple and easy to apply, and shows a large degree of consistency between the grading of therapeutic and preventive, prognostic and diagnostic studies. The system is based on the original ratings of the AHCPR Guidelines (1994) and levels of evidence recommended in the method guidelines of the Cochrane Back Review group. The strength of the

Several of the existing systematic reviews have included non-English language literature, usually publications in French, German, and Dutch language and sometimes also Danish, Norwegian, Finnish and Swedish. All existing national guidelines included studies published in their own language. Consequently, the non- English literature is covered for

The group additionally included the Spanish literature, because this evidence was not

The Working Group aimed to identify gaps in the literature and included recommendations

Constitution of the multidisciplinary working group through a Management Committee composed of experts in field of low back pain, appointed by the Governments of 14 countries participating in European Union, framed in the Directorate General Research, Political Co-ordination and Strategy (COST) and B13 program "Low back Pain: Guidelines

**COST B13 European program** 

by personal communication with experts in the field.

diagnosis have a letter D, treatment T.

recommendations was not graded.

countries that already have developed guidelines.

**5.1 Constitution of the multidisciplinary working group** 

covered by existing reviews and guidelines.

for future research. Basic Sequence:

for its management".

To streamline the work plan were drafting chapters on acute low back pain, chronic and prevention, stratified components in 3 sub-working groups. Finally, in our case was working Spanish Group for improvement and adaptation directed by the Spanish representatives of European Management Committee.

#### **5.2 Search and selection of scientific evidence**

Search and selection of scientific evidence by means computerized databases and documentary looking time period more comprehensive as possible, with strategies to include those available in languages other than English, particularly in Spanish, but also supplement with contributions of studies which were undergoing investigation or publication, but excluding not accepted.

Explored databases were Cochrane, Medline, Embase, health Star, Pascal, PsycINFO, SPORT ciscos, Biosis, Lilacs and EMI.

#### **5.3 Methodological evidence quality assessment**

Methodological evidence quality assessment detected in each systematic review and original studies found according to Oxman and Guyatt methodological criteria (annex 2 GPC COST)

#### **5.4 Levels of evidence for recommendations**

Levels of evidence for recommendations arising from number of studies that underlie them, quality methodology and consistency results, according to criteria based on guidance of advice (Bigos1994) and "levels of evidence" recommended by the Cochrane Collaboration back group (van Tulder 2003). (Table 4)

```
Level A : Results of a systematic¨ review of multiple studies* (high quality).
Level B : Results of a systematic¨ review of studies* (low quality). 
Level C : Results of a single study * (high or low quality), 
or inconsistent systematic¨ review of multiple studies. 
Level D : Non-obviousness (lack of studies).
```
Table 4. Evidence Levels

*¨Criterion of "Systematic review": use of systematic methods to select and include studies, assessment of methodological quality and extraction and analysis of data. Are defined as "results consistent to the coincidence in the sense of the results, at least 75% of the studies".\* Studies: diagnostic, prognosis (prospective), treatment (controlled clinical trial), prevention (controlled clinical trial)* 

#### **5.5 Review and approval content of Guide**

Review and approval content of Guide once analysed available scientific evidence each group developed recommendations and discussion according to a fixed timetable, by electronic means and meetings seeing them joint the overall content of the Guide, articulating a mechanism of critical inter groups until approval by unanimity.

#### **5.6 Spanish adaptation by the Working Group**

Spanish adaptation by the Working Group formed with the aim of:

The Treatment of Low Back Pain and Scientific Evidence 61

#### **5.6.1 Help detect and collect evidence in Spanish**

Help detect and collect evidence in Spanish might have been forgotten in e-strategies prior.

#### **5.6.2 Critical analysis**

Critical analysis:Successive drafts produced by work groups.

#### **5.6.3 Adaptation**

To Spanish health system, dissemination and use of GPC elaborated by working groups. The Spanish adaptation is stuck studying organizational aspects necessary for recommendations implementation, definition targets, measurement organization and registration indicators systems, implementation and identification of local barriers to be overcome.

#### **5.6.4 Application of the criteria of the instrument AGREE**

Application of the criteria of the instrument AGREE, and detection of gaps in the previous format (International) as: not-identification of target user, lack of tools to facilitate practical application, or establishment methods to make e final recommendations, and non-inclusion of declarations interest conflicts.

#### **5.6.5 Updating of the Guide COST B13**

Through following mechanisms: regular meetings of representatives of participating entities, provision of sources of funding for an automated mechanism for detection, analysis and aggregation of results of further studies. Use as a basis for updates Cochrane Collaboration systematic reviews relating to clinical trials on therapeutic technologies, and formation of a network of evaluation teams in studies published in mentioned area.

#### **5.6.6 Declaration of conflicts of interest**

Economic, effective type or species, direct or indirect, generic or specific, personal or collective produced or expected, that goes beyond use of technologies which mentioned in a clinical setting or research purposes. Performed in nominal and explicit way by components of the Spanish working group and contained in a table extensive version.

#### **5.7 Guide publication by previously established, varied media**

Written in extended version including a management role and through free electronic access algorithm through www.REIDE.org . In GPC said based on scientific evidence, specify all relevant studies for each specific recommendation, analyzes town methodology and are non-technical summary evidence on efficiency, effectiveness, safety and cost/effectiveness and indications of each treatment.

#### **5.7.1 Algorithm**

Integrates all information is published on paper and you can print from electronic access, consists of a flow diagram that includes evidence of each recommended technology and designed to take up a minimum space, is Pocket-Guide.

Help detect and collect evidence in Spanish might have been forgotten in e-strategies prior.

To Spanish health system, dissemination and use of GPC elaborated by working groups. The Spanish adaptation is stuck studying organizational aspects necessary for recommendations implementation, definition targets, measurement organization and registration indicators

Application of the criteria of the instrument AGREE, and detection of gaps in the previous format (International) as: not-identification of target user, lack of tools to facilitate practical application, or establishment methods to make e final recommendations, and non-inclusion

Through following mechanisms: regular meetings of representatives of participating entities, provision of sources of funding for an automated mechanism for detection, analysis and aggregation of results of further studies. Use as a basis for updates Cochrane Collaboration systematic reviews relating to clinical trials on therapeutic technologies, and

Economic, effective type or species, direct or indirect, generic or specific, personal or collective produced or expected, that goes beyond use of technologies which mentioned in a clinical setting or research purposes. Performed in nominal and explicit way by components

Written in extended version including a management role and through free electronic access algorithm through www.REIDE.org . In GPC said based on scientific evidence, specify all relevant studies for each specific recommendation, analyzes town methodology and are non-technical summary evidence on efficiency, effectiveness, safety and cost/effectiveness

Integrates all information is published on paper and you can print from electronic access, consists of a flow diagram that includes evidence of each recommended technology and

formation of a network of evaluation teams in studies published in mentioned area.

of the Spanish working group and contained in a table extensive version.

**5.7 Guide publication by previously established, varied media** 

designed to take up a minimum space, is Pocket-Guide.

**5.6.1 Help detect and collect evidence in Spanish** 

Critical analysis:Successive drafts produced by work groups.

**5.6.4 Application of the criteria of the instrument AGREE** 

systems, implementation and identification of local barriers to be overcome.

**5.6.2 Critical analysis** 

of declarations interest conflicts.

**5.6.5 Updating of the Guide COST B13** 

**5.6.6 Declaration of conflicts of interest** 

and indications of each treatment.

**5.7.1 Algorithm** 

**5.6.3 Adaptation** 

Clarification of Algorithm

a. Emergency Surgery if progresive or bilateral paresis, loss of bladder control or sadle

b. Severe Radicular pain > 6 weeks despite all non surgery treayments (disc herniation ). Or only withwalking, needs flexion or sitting, is longer > 6 months and there are images of

**B** For systemic pathology: values X-ray, simple analysis, MRI in early pain in <20 o > 50 years old, dorsal, at night,, neurologic défficit,diffuse, flexion 5º failed, deformation,malaise, loss weigth, fever, neoplasms, corticosteroids, trauma, intranenous addictions, inmunosuppression

**C** Information patient: Avoid bed rest, nonspecific back pain not due to serious illnes, pain emanating from structures of the spine, spontaneous resolved to 2-6 weeks. To speed recoveryand

**D** First line Drugs: Paracetamol 650-1000 mgs each 6-8 hours, AINEs < 3 months, muscle

**F** Neuroreflexotherapy (NRT) : if LBP >2 weeks, moderate to intense (>3 points of 1-10 scale)

**H** Brief Educative Programs: Pocket back Manual, chat with patient for positive reinforcement,

**I** Cognitive-behavioral treatment: Only if LBP > 6 weeks with signals of poor functional prognosis ,potentially active work situation, LBP intense and > 3 months with failure of

**O** Arthrodesis Preferable not instrumented only if disabling pain > 2 years despite all treatments

**P** Multidisciplinary programs: Intensive and combined D, E, I, K and M , by Psychologist,

(Based on Figure 1 (Management Algorithm) pg 13-14. And CPG Spanish version pocket guide,

Latorre Marques E., Kovacs F., Gil del Real Mª T., Alonso P., Urrutia G.: Spanish version of COST B13 Guide: A clinical pactical guideline for non-specific back pain based on scientific evidence. *Dolor* 2008;

reduce the risk of recurrence mantainphysical activity including work if possible.

**E** Exercise: Not before 2-6 weeks of episode, as preventive and treatment.

internet direction with consistent information (www.espalda.org).

**L** Capsaicin Patches: If intense pain ( >5 points of 1-10 scale)

Physiotherapist and Medical staff in specialized units.

**M** Opiates: Patterned and slow-release with strict medical control.

Fig. 2. Management Algorithm of LBP based on Scientific Evidence.

treatments or with exercise instead of surgery in degenerative spondylosis.

**J** Back School: Not centered in traditional education but in activity maintenance.

**A** For referral to surgery :

spinal stenosis.

anesthesia.

relaxants < 1 week.

and there are one acredited unit.

**G** Signals of Poor functional prognosis

**K** Antidepressants: Analgesic dosing.

**N** Peripheral Neuro-Stimulation (PNS)

maximum 2 segments of spine.

disposable in www.REIDE.org

23: 7-17)

or AIDS.

#### Clarification of Algorithm

**A** For referral to surgery :


**B** For systemic pathology: values X-ray, simple analysis, MRI in early pain in <20 o > 50 years old, dorsal, at night,, neurologic défficit,diffuse, flexion 5º failed, deformation,malaise, loss weigth, fever, neoplasms, corticosteroids, trauma, intranenous addictions, inmunosuppression or AIDS.

**C** Information patient: Avoid bed rest, nonspecific back pain not due to serious illnes, pain emanating from structures of the spine, spontaneous resolved to 2-6 weeks. To speed recoveryand reduce the risk of recurrence mantainphysical activity including work if possible.

**D** First line Drugs: Paracetamol 650-1000 mgs each 6-8 hours, AINEs < 3 months, muscle relaxants < 1 week.

**E** Exercise: Not before 2-6 weeks of episode, as preventive and treatment.

**F** Neuroreflexotherapy (NRT) : if LBP >2 weeks, moderate to intense (>3 points of 1-10 scale) and there are one acredited unit.

**G** Signals of Poor functional prognosis

**H** Brief Educative Programs: Pocket back Manual, chat with patient for positive reinforcement, internet direction with consistent information (www.espalda.org).

**I** Cognitive-behavioral treatment: Only if LBP > 6 weeks with signals of poor functional prognosis ,potentially active work situation, LBP intense and > 3 months with failure of treatments or with exercise instead of surgery in degenerative spondylosis.

**J** Back School: Not centered in traditional education but in activity maintenance.

**K** Antidepressants: Analgesic dosing.

**L** Capsaicin Patches: If intense pain ( >5 points of 1-10 scale)

**M** Opiates: Patterned and slow-release with strict medical control.

**N** Peripheral Neuro-Stimulation (PNS)

**O** Arthrodesis Preferable not instrumented only if disabling pain > 2 years despite all treatments maximum 2 segments of spine.

**P** Multidisciplinary programs: Intensive and combined D, E, I, K and M , by Psychologist, Physiotherapist and Medical staff in specialized units.

(Based on Figure 1 (Management Algorithm) pg 13-14. And CPG Spanish version pocket guide, disposable in www.REIDE.org

Latorre Marques E., Kovacs F., Gil del Real Mª T., Alonso P., Urrutia G.: Spanish version of COST B13 Guide: A clinical pactical guideline for non-specific back pain based on scientific evidence. *Dolor* 2008; 23: 7-17)

Fig. 2. Management Algorithm of LBP based on Scientific Evidence.

The Treatment of Low Back Pain and Scientific Evidence 65

Until the year 2005 revisions and CPG´s served to help primary care to manage only acute low back pain. Few documents provided outcome assessment, until emergence of CPG

Inclusion of basic principles management summary and outcome assessment in low back pain, that daily practice medicine, scientific evidence based, makes this CPG a reliable

Our working group decided include "Criteria to define the evidence needed to develop

 For studies considered for each analysis group (builds clinicians, in addition to controlled clinical trials in chronic low back pain and studies on prevention in the

 Refer to specific field of each group (acute, chronic low back pain and prevention) and mechanisms of warning mutual between groups given overlapping populations

 Relevant analysis of variable for each field. In case of treatments for acute and chronic low back pain: pain intensity, degree of disability, level of quality of life or absenteeism

Numerous adaptations and improvements (Pillastrini P 2011) have been developed. Comparing the quality of the CPG´s from 2004 until today for LBP has improved, however developers need to still increase quality transparency process, especially with regard

The process of the CPG´s is still costly in economic resources and time, in best cases for up to 4 years is therefore possible that arise this period new evidence should incorporate, to which review mechanisms should be established involving staff sufficiently prepared both clinical management and analysis of the scientific evidence. For this reason must obtain support of scientific entities and non-profit publishers to remain independent and

In our case, was obtained scientific and professional broadest possible support, described favorably by evaluation agencies in health technology, approved by CPG of national health system catalog (GuiaSalud), applied in hospitals and health centers. Its use was recommended by entities as Council official schools of Spain doctors, but unlike other CPG´s included support for consumer organizations in health services. Our version

However from reading our guide has emerged a contradiction in the meaning of the scientific evidence available at that time because we do not recommended the use of Botulinum Toxin for chronic low back pain treatment, although at that time there was a controlled trial which demonstrated their effectiveness, but after analysis observed low methodological quality and low scale of clinical effects reflected without compensating for the risks of its use. Also our version not recommended vertebral manipulation, while European version was Yes. This is due to the Spanish working group could discuss

**6. Discussion** 

instrument.

recommendations":

corresponding group). Referred to non-specific.

/ return to work.

included in systematic reviews or studies.

professionals without conflict of interest.

editorial applicability and independence (Bouwmeester W, 2009).

identifies concrete entities of explicit, improving transparency.

COST B13 program of European Union.

Fig. 3. Development schedule of a CPG based on scientific evidence

Attached and rear face contains explanatory notes of management; as can be seen is integrated into a single temporal sequence low back pain acute, sub-acute and chronic.

#### **5.7.2 Recommendations summary GPC of low back pain**

Reflected in a 22 page booklet and contains information relating recommended diagnostic process, recommended treatments based on scientific evidence, technologies not recommended for treatment, prevention of occurrence, or recurrence, and handling algorithm. It can also be downloaded on the internet. Includes authors and reviewers, as well as relevant national entities adopting recommendations.

One of novelties is incorporation of treatments cognitive-behavioral early mode and early detection of signs of poor functional prognosis by simple and specific tests (Table 5).


Table 5. Signs of poor functional prognosis and recommended treatment

### **6. Discussion**

64 Low Back Pain

Fig. 3. Development schedule of a CPG based on scientific evidence

**5.7.2 Recommendations summary GPC of low back pain** 

well as relevant national entities adopting recommendations.

Mistaken beliefs Misconduct Occupational factors Emotional problems

Attached and rear face contains explanatory notes of management; as can be seen is integrated into a single temporal sequence low back pain acute, sub-acute and chronic.

Reflected in a 22 page booklet and contains information relating recommended diagnostic process, recommended treatments based on scientific evidence, technologies not recommended for treatment, prevention of occurrence, or recurrence, and handling algorithm. It can also be downloaded on the internet. Includes authors and reviewers, as

One of novelties is incorporation of treatments cognitive-behavioral early mode and early

**Signs of poor functional prognosis Recommended treatments** 

Interview training Written validated information Electronic information Brief educational program

detection of signs of poor functional prognosis by simple and specific tests (Table 5).

Table 5. Signs of poor functional prognosis and recommended treatment

Until the year 2005 revisions and CPG´s served to help primary care to manage only acute low back pain. Few documents provided outcome assessment, until emergence of CPG COST B13 program of European Union.

Inclusion of basic principles management summary and outcome assessment in low back pain, that daily practice medicine, scientific evidence based, makes this CPG a reliable instrument.

Our working group decided include "Criteria to define the evidence needed to develop recommendations":


Numerous adaptations and improvements (Pillastrini P 2011) have been developed. Comparing the quality of the CPG´s from 2004 until today for LBP has improved, however developers need to still increase quality transparency process, especially with regard editorial applicability and independence (Bouwmeester W, 2009).

The process of the CPG´s is still costly in economic resources and time, in best cases for up to 4 years is therefore possible that arise this period new evidence should incorporate, to which review mechanisms should be established involving staff sufficiently prepared both clinical management and analysis of the scientific evidence. For this reason must obtain support of scientific entities and non-profit publishers to remain independent and professionals without conflict of interest.

In our case, was obtained scientific and professional broadest possible support, described favorably by evaluation agencies in health technology, approved by CPG of national health system catalog (GuiaSalud), applied in hospitals and health centers. Its use was recommended by entities as Council official schools of Spain doctors, but unlike other CPG´s included support for consumer organizations in health services. Our version identifies concrete entities of explicit, improving transparency.

However from reading our guide has emerged a contradiction in the meaning of the scientific evidence available at that time because we do not recommended the use of Botulinum Toxin for chronic low back pain treatment, although at that time there was a controlled trial which demonstrated their effectiveness, but after analysis observed low methodological quality and low scale of clinical effects reflected without compensating for the risks of its use. Also our version not recommended vertebral manipulation, while European version was Yes. This is due to the Spanish working group could discuss

The Treatment of Low Back Pain and Scientific Evidence 67

wish to be taken seriously, give clear and understandable feedback during consultation, and

Is needed to improve structuring of multidisciplinary and low cost consultation (Laerum E, 2006), and indicate only surgery treatment in selected cases, by minimally invasive

The other hand we must improve the procedures for developing clinical trials to make them consistent, and adopt the quality standards in obtaining scientific evidence; for this are emerging tools that help groups and conduct systematic reviews using criteria of quality,

Author thanks the Spanish work Group members of COST B13 program \*, and Pérez Barrero P. Specialist in Anesthesiology and Plastic/Reconstructive Surgeon, MD of "Miguel

**\***List of members shown in Table 1 (Pg. 10) ; Dolor I*nvestigacion clinica & terapeutica*. 2008 23:

Any financial and nonfinancial conflict of interest of Spanish work group of COST B13 program were declared, discussed, and resolved. Disclosures can be viewed at http:// www.REIDE.org / or the subsequent publication: "Guide to clinical practice of nonspecific low back pain, Spanish version of the Guide to clinical practice of the European program

Airaksinen O, et al. On behalf of the COST B13 Working Group on Guidelines for

Altman DG, et al. EQUATOR: reporting guidelines for health research. Lancet 2008;

Biering Sorensen F. A prospective study of low back pain in a general population. Scand J

Bigos S, et al. Acute low back pain in adults. Clinical practice guideline. No. 14 , AHCPR

Blau JN, Logue V. A natural history of intermitent claudication fo the cauda equina. Brain

Bogduk N, on behalf of the Australasian Faculty of Muskuloskeletal Medicine for the

management of acute low back pain. 1999 November.

of chronic low back pain . Eur Spine J 2006; 15 (suppl 2) :S192-300.

Prevention in low back pain. Chapter 4. European Guidelines for the management

publication No. 95-0642. Rockville (MD): Agency of Health Care Policy and Research, Public Health Service, US Department of Health and Human Services ;

Muskuloskeletal Medicine Initiative. Evidence –Based Clinical guidelines for the

transparency and independence. Hope this chapter helps to achieve these objectives.

Servet Hospital", for suggestions and review of translation style.

discuss what can be done.

**8. Acknowledgments** 

**9. Potential conflicts of interest** 

COST B13" Legal deposit M-49781-Madrid, Spain.

Rehabil Med 1983; 15 (2): 71-9.

techniques.

7-17

**10. References** 

371:1149e50.

1978; 101: 2111-15.

1994.

publications that appeared after first had been released, which showed methodological errors that inclined in negative sense and therefore not apply in daily clinical practice, and still less be taken in National Health Spanish System (Kovacs FM, 2005).

Other technologies that have in Spain anecdotal usage data, such as ozone therapy or drug enforcement anti-TNF (Tumor Necrosis Factor), were discarded for lack of evidence on efficacy, safety or efficiency, after incorporating them by the Spanish working group, to a new analysis of quality whose result was negative.

As evaluated and treatments "not recommended" used in the "treatment of pain unit" also disputes that remain have been (American Pain Society, Chou & Hoyt Huffman, 2009) for the application of nerve blocks in the treatment of low back pain.

Sacroiliac Joint Blockade did not provide evidence that special use, even the infiltration with corticosteroids is no better than placebo (level C), epidural injections were not recommended in non-specific LBP (Level D), however this option can arise in the case of root compression symptomatic herniated disc contained and not extruded, obtaining better results combined with corticosteroid and local anesthesics and is cost-effective (Karpinen J) (2001). Facet injections with corticosteroids were not superior to placebo (level B), and combinations of steroids and local anesthetics were similar to anesthetic alone (level C) effectiveness, therefore not recommended them. Similarly, infiltrations and electrotherapy intra-disc, and facet-joint radiofrequency showed no conclusive data in 2005, probably by the poor quality of the studies, but long series has now been re-designed, with assessment of cost effectiveness and improvement of methodological quality seem to support its use in selected circumstances (Manchikanti L., 2010).

Other low back pain versions CPG´s lack elicitation in relation to the criteria of organizational adaptation to various health services and ensure coordination and efficiency, so the Spanish version includes a process for identification of local variations in story to the applicability and adaptation mechanisms.

Given that the Pan-European version finished his project in 2005, we decided to update mechanisms, based on the detection and analysis of the evidence that arise in the future, marking a timetable for action that also incorporated social and scientific entities to improve adherence and outcomes (Spanish working group program COST B13 2005).

#### **7. Conclusion**

Low back pain is a common and potentially disabling condition in adults, and included numerous treatment options. The best available evidence currently suggest that in absence of serious spinal pathology, specific causes of non-spinal origin or progressive neurologic deficit, management should focus on patient education, self-care, common analgesics and exercise.

Short term relief in radiating pain may be obtained with epidural blockade with local anesthetics and steroids, or facet blocks in selected cases. Peripheral Neuromodulation (PNS) and Neuro-Reflex-Therapy (NRT) can offer good results in LBP.

For patients with psychological comorbidities, cognitive-behavioral therapy or multidisciplinary rehabilitation is appropriate. Participation of patient is crucial: patient wish to be taken seriously, give clear and understandable feedback during consultation, and discuss what can be done.

Is needed to improve structuring of multidisciplinary and low cost consultation (Laerum E, 2006), and indicate only surgery treatment in selected cases, by minimally invasive techniques.

The other hand we must improve the procedures for developing clinical trials to make them consistent, and adopt the quality standards in obtaining scientific evidence; for this are emerging tools that help groups and conduct systematic reviews using criteria of quality, transparency and independence. Hope this chapter helps to achieve these objectives.

#### **8. Acknowledgments**

66 Low Back Pain

publications that appeared after first had been released, which showed methodological errors that inclined in negative sense and therefore not apply in daily clinical practice, and

Other technologies that have in Spain anecdotal usage data, such as ozone therapy or drug enforcement anti-TNF (Tumor Necrosis Factor), were discarded for lack of evidence on efficacy, safety or efficiency, after incorporating them by the Spanish working group, to a

As evaluated and treatments "not recommended" used in the "treatment of pain unit" also disputes that remain have been (American Pain Society, Chou & Hoyt Huffman, 2009) for

Sacroiliac Joint Blockade did not provide evidence that special use, even the infiltration with corticosteroids is no better than placebo (level C), epidural injections were not recommended in non-specific LBP (Level D), however this option can arise in the case of root compression symptomatic herniated disc contained and not extruded, obtaining better results combined with corticosteroid and local anesthesics and is cost-effective (Karpinen J) (2001). Facet injections with corticosteroids were not superior to placebo (level B), and combinations of steroids and local anesthetics were similar to anesthetic alone (level C) effectiveness, therefore not recommended them. Similarly, infiltrations and electrotherapy intra-disc, and facet-joint radiofrequency showed no conclusive data in 2005, probably by the poor quality of the studies, but long series has now been re-designed, with assessment of cost effectiveness and improvement of methodological quality seem to support its use in

Other low back pain versions CPG´s lack elicitation in relation to the criteria of organizational adaptation to various health services and ensure coordination and efficiency, so the Spanish version includes a process for identification of local variations in story to the

Given that the Pan-European version finished his project in 2005, we decided to update mechanisms, based on the detection and analysis of the evidence that arise in the future, marking a timetable for action that also incorporated social and scientific entities to improve

Low back pain is a common and potentially disabling condition in adults, and included numerous treatment options. The best available evidence currently suggest that in absence of serious spinal pathology, specific causes of non-spinal origin or progressive neurologic deficit, management should focus on patient education, self-care, common analgesics and

Short term relief in radiating pain may be obtained with epidural blockade with local anesthetics and steroids, or facet blocks in selected cases. Peripheral Neuromodulation

For patients with psychological comorbidities, cognitive-behavioral therapy or multidisciplinary rehabilitation is appropriate. Participation of patient is crucial: patient

adherence and outcomes (Spanish working group program COST B13 2005).

(PNS) and Neuro-Reflex-Therapy (NRT) can offer good results in LBP.

still less be taken in National Health Spanish System (Kovacs FM, 2005).

the application of nerve blocks in the treatment of low back pain.

new analysis of quality whose result was negative.

selected circumstances (Manchikanti L., 2010).

applicability and adaptation mechanisms.

**7. Conclusion** 

exercise.

Author thanks the Spanish work Group members of COST B13 program \*, and Pérez Barrero P. Specialist in Anesthesiology and Plastic/Reconstructive Surgeon, MD of "Miguel Servet Hospital", for suggestions and review of translation style.

**\***List of members shown in Table 1 (Pg. 10) ; Dolor I*nvestigacion clinica & terapeutica*. 2008 23: 7-17

#### **9. Potential conflicts of interest**

Any financial and nonfinancial conflict of interest of Spanish work group of COST B13 program were declared, discussed, and resolved. Disclosures can be viewed at http:// www.REIDE.org / or the subsequent publication: "Guide to clinical practice of nonspecific low back pain, Spanish version of the Guide to clinical practice of the European program COST B13" Legal deposit M-49781-Madrid, Spain.

#### **10. References**


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improvement. JAMA 1999; 282:1458-65.

PubMed journals. Lancet. 2005;365:1159-62.


**3** 

J. Nicholas Penney

*Australia* 

*University of Queensland,* 

**Estimation of Prognosis in Non Specific Low** 

*Centre of National Research on Disability and Rehabilitation Medicine,* 

**Back Pain from Biopsychosocial Perspectives** 

The significance of low back pain and associated disability across many western nations continues to be an important issue. Pain and disability associated with musculoskeletal conditions represents a significant health and economic burden in Australia, with total direct and indirect costs of musculoskeletal disorders including arthritis being in excess of

In the USA the data from the 1998 Medical Expenditure Panel Survey, reported that health care expenditure incurred by individuals with back pain reached in excess of 90 billion dollars. Individuals with back pain also incurred 60% more health care costs than those

There is also a growing literature that supports the contention that low back pain is a complex, multidimensional health issue and should be reviewed within the context of the

Evidence-based clinical practice guidelines, such as those produced in Australia in 2003 emphasise the importance of the biopsychosocial model in the understanding of pain in general and musculoskeletal pain in particular (AAMPG. 2003). The biopsychosocial model focuses on illness, communicating or behaving in a manner that suggests the individual is not well, rather than on disease, the person's experience of illness being influenced by physical, psychological and social factors (Engel. 1980). Engel's model highlighted that in order to respond adequately to an individuals suffering, and give them a sense of being understood, the clinician needed to be able to respond simultaneously to the biological,

The model incorporates the biomedical understanding of nociception as part of the wider holistic biopsychosocial view, rather than treating psychosocial factors as an 'overlay' to the

Philosophically the model is a way of understanding how suffering, disease and illness may be affected by mulitple levels of organisation, from the molecular to societal. Practically, the model provides a way of understanding the patient's subjective experiance as an essential

psychological and social dimensions of illness (Borrell-Carrio,Suchman et al 2004)

contributor to accurate clinical diagnosis and assessment (Borrell-Carrio et al 2004).

**1. Introduction** 

biomedical model.

15 billion dollars per annum (AAMPG. 2003).

without (Luo, Pietrobon et al. 2003).

individual (Young,Waisiak, et al 2011).


### **Estimation of Prognosis in Non Specific Low Back Pain from Biopsychosocial Perspectives**

J. Nicholas Penney

*Centre of National Research on Disability and Rehabilitation Medicine, University of Queensland, Australia* 

#### **1. Introduction**

70 Low Back Pain

Research on work related low back disorders. Luxembourg Office for Official Publications of

Rico Iturrioz R, Gutiérrez-Ibarluzea I, Asua Batarrita J, Navarro Puerto MA, Reyes

Saal JA, Saal JS, Herzog RJ. The natural history of lumbar intervertebral disc extrusions

Saal JA. Natural history and nonoperative treatment of lumbar disc nerniation. Spine 1996;

Sackett, D L et al. Evidence-Based Medicine: How to Practice and Teach EBM. New York:

Shaneyfelt TM, Mayo-Smith MF, Rothwangl J. Are Guidelines Following Guidelines? The

Simera I, et al. Guidelines for reporting health search: The EQUATOR network´s survey of guideline autors. PLoS Med. 2008; 5:e139, doi: 10.1371/journal.pmed.0050139. Special Eurobarometer 272/Wave 66.2 - TNS Opinion 6 Social European Commission,

Spengler D, Bigos SJ , Martin NA, et al. Back injuries at industry: a retrospective study. I

Straus BN. Chronic pain of spina origin: The costs of intervention. Spine 2002;27:2614-2619. The AGREE Collaboration. Development and validation of an international appraisal

The bone and joint deacade Report, 2005, European Action Towards Better Musculoskeletal

V Encuesta Nacional de Condiciones de Trabajo Octubre 2004 , Instituto Nacional de

Van Tulder MW, Kovacs FM, Mueller G, et al. European commission COST B13

Veerle Hermans, "Research on work-related low backa pain disorders, Institute for

Walker BF. The prevalence of low back pain: a systematic review of the literature from 1966

Methodological Quality of Clinical Practice Guidelines in the Peer Reviewed

instrument for assessing the quality of clinical practice guidelines: The AGREE

Health; European League Against Rheumatism (EULAR), European Federation of Nationa Associations of Orthopaedics and Traumatology (EFFORT) 6 International

Higiene y Seguridad en el Trabajo (Fifth National Survey on Working Conditions, INSHT The Spanish National institute of Safety and Hygiene in the Workplace). Van tulder MW, Koes BW, Bouter JM. A cost-illnes study of back pain in the Netherlands.

Management Committee: European Guidelines for the management of low back

Domínguez A, Marín León I, Briones Pérez de la Blanca E. Valoración de escalas y criterios para la evaluación de las Guías de Práctica Clínica Rev Esp Salud Pública

the European Union (2000), ISBN 92 95007 02 6.

treated non-operatively. Spine 1990; 683-86.

Medical Literature. JAMA 1999:281(20):1900-1905

overview and cost analysis. Spine 1986; 11:141-5.

proyect. Qual Saf Health Care 2003;12:18-23.

pain. Acta Orthop Sacand 2002; 73 Suppl 305:20-5.

Watkins et al. Silent pain sufferers. Mayo Clin Proc 2006; 81:167-71.

Wipf JE, Deyo RA. Low back pain. Med Clin North Am 1995; 79(2): 231-46.

Occupational Safety and Health, Brussels.

to 1998. J Spinal Disord 2000; 13(3)205-17.

Osteoporosis Foundation (IOF).

Pain 1995; 62 (2): 233-40-

September 2007. Health in the European Union. 17-30.

2004;78:457-467

Churchill Livingstone.1997.

21:2S-9S.

The significance of low back pain and associated disability across many western nations continues to be an important issue. Pain and disability associated with musculoskeletal conditions represents a significant health and economic burden in Australia, with total direct and indirect costs of musculoskeletal disorders including arthritis being in excess of 15 billion dollars per annum (AAMPG. 2003).

In the USA the data from the 1998 Medical Expenditure Panel Survey, reported that health care expenditure incurred by individuals with back pain reached in excess of 90 billion dollars. Individuals with back pain also incurred 60% more health care costs than those without (Luo, Pietrobon et al. 2003).

There is also a growing literature that supports the contention that low back pain is a complex, multidimensional health issue and should be reviewed within the context of the individual (Young,Waisiak, et al 2011).

Evidence-based clinical practice guidelines, such as those produced in Australia in 2003 emphasise the importance of the biopsychosocial model in the understanding of pain in general and musculoskeletal pain in particular (AAMPG. 2003). The biopsychosocial model focuses on illness, communicating or behaving in a manner that suggests the individual is not well, rather than on disease, the person's experience of illness being influenced by physical, psychological and social factors (Engel. 1980). Engel's model highlighted that in order to respond adequately to an individuals suffering, and give them a sense of being understood, the clinician needed to be able to respond simultaneously to the biological, psychological and social dimensions of illness (Borrell-Carrio,Suchman et al 2004)

The model incorporates the biomedical understanding of nociception as part of the wider holistic biopsychosocial view, rather than treating psychosocial factors as an 'overlay' to the biomedical model.

Philosophically the model is a way of understanding how suffering, disease and illness may be affected by mulitple levels of organisation, from the molecular to societal. Practically, the model provides a way of understanding the patient's subjective experiance as an essential contributor to accurate clinical diagnosis and assessment (Borrell-Carrio et al 2004).

Estimation of Prognosis in Non Specific Low Back Pain from Biopsychosocial Perspectives 73

The study reported in this chapter tested the hypothesis that it would be feasible to develop a valid and reliable instrument for estimating the prognosis of non specific low back pain

Ethical approval for each step of the instrument's development was obtained from the ethics

The components of the resultant instrument (termed the Biopsychosocial Index of Prognosis (BPIP)) were developed from the literature review and perspective of a logical course of clinical enquiry into the current and past episodes of low back pain. The nature and character of the pain together with the severity, spread and duration of the symptoms were also included in the draft questionnaire. Past and present medical and psychological histories were considered together with demographic details including occupation. The items generated were combined into a content map derived from the International Classification of Function (ICF). Initial item generation included items from previously validated instruments identified from the literature where possible. The draft index initially contained 145 items. The large pool of items were initially included in the prototype questionnaire, which was progressively and systematically subjected to item reduction. The necessity for this process of item reduction was established a priori, and driven by the lack of feasibility of carrying a large number of potentially redundant items through to the validation stage of the instruments development (Bellamy, Campbell et al. 2002). The development of the BPIP potentially filled a gap in measurement, estimating prognosis from a variety of biopsychosocial domains and driven by clinical, rather than theoretical

Thie chapter describes the development of the BPIP including the steps taken in item reduction and reports on testing the validity of the final instrument, and its reliability against the 'gold standard' measure identified as the Roland and Morris disability questionnaire (RDQ) (Roland and Morris. 1983). The RDQ is one of the most frequently reported instruments used to assess the disability associated with low back pain. The RDQ was also the criterion measure selected for the previous work of Burton and co-workers on psychosocial predictors (Burton, Tillotson, Main and Hollis 1995). A variety of other instruments were considered from the literature including the Orebro Musculoskeletal Pain Questionnaire (Linton and Hallden. 1998) as the potential gold standard. However the focus was on the wider community with low back pain, not just workers with acute low back

The initial assessments of the prototype index were undertaken in three distinct phases In phase one, piloting was undertaken with a small group without low back pain, consisting of five health care professionals from a variety of disciplines and from different English spreaking countries including England, Australia and New Zealand. and chosen for their academic and general life experiance. The primary focus of the first pilot trial was to obtain feedback on the pool of items selected for evidence of any ambiguity or repetition, ease of

administration and the overall comprehensiveness of the questionnaire.

from within the biopsychosocial domain, suitable for routine clinical use.

committee, University of Queensland, Australia.

pain, so the RDQ remained the instrument of choice.

perspectives.

**2. Methods** 

**2.1 Development of the BPIP** 

There has been increasing acceptance that psychosocial factors play a significant role in the transition from an acute episode, or episodes, of low back pain to a chronic disorder(Pincus, Burton, et al. 2002). There is also some evidence that these factors may play an aetiological role (Pincus et al. 2002) (Linton. 2000) (Trouchon, and Fillion. L.2000).

The acceptance of the wider biopsychosocial model has been further extended by the World Health Organisation's (WHO) International Classification of Functioning, Disability and Health (ICF) (WHO. 2000).

Many individual psychological factors have been reported over the years as potential obstacles to recovery, with much of the early work centred around fear. Initially the work focussed around the fear avoidance model of exaggerated pain perception in chronic low back develpoed by Lethem and co-workers (Lethem, Slade, Troup, Bentley. 1983). The Fear-Avoidance Belief Questionnaire developed by Waddell and co-workers published in 1993 measured beliefs about physical activity and work (Waddell, Somerville, Henderson, Newton, Main 1993). Workers with low back pain were shown to believe that physical activity including work was feared to increase both spinal pain and damage. These fear avoidant beliefs helped to explain self reported disability in normal daily activities including work( Waddell et al 1993).

Fear of pain together with fear of hurt or harm were further postulated as a fundemental mechanism of disability associated with low back pain were explored by Vlaeyen and Linton. The natural human reaction to pain is an automatic one to try and avoid what is belived to be the cause of the pain, ongoing fear then potentially drives further avoidant behavior(Vlaeyen and Linton 2000).

Contrary to the weight of evidence however, surveys of primary contact practitioners continue to indicate that general practitioners for instance, may only be partially managing low back pain from this evidence-based perspective. This may be due in part to the difficulties reported in changing physician behaviour (Buchbinder, Staples et al. 2009) and then further highlighted by the difficulty reported in integrating the biopsychosocial model into clinical disiplines, such as physiotherapy (Harland and Lavallee. 2003). The potential difficulties in fully incorporating a biopsychosocial approach to patients, appear to transcend professional training and boundaries, as Harding and co-workers reported in 2010. Whilst pain clinic practioners in the UK embrase behavioural based management as part of a biopsychosocial pain management model, little consideration was given to social factors (Harding, Campbell et al 2010).

The estimation of prognosis (identifying those at risk of a poor outcome such as ongoing pain or disability, or failing to return to work) of an episode of low back pain is particularly important to clinicians, patients, employers and third party payers alike. However despite the weight of evidence there remains a tendancy to rely on instruments that quantify prognostic factors from a biomedical perspective alone, rather than the contemporary biopsychosocial model, whilst focusing on return to work as a single outcome. A predictive instrument that may help clinicians fully incorporate the biopsychosocial model into clinical practice clearly has some utility, and whilst it has been suggested that such an instrument needs to capture all the potential biopsychosocial risk factors that may adversely affect functional outcomes (Hilficker, Bachmann, et al. 2007), an initial attempt to produce such a draft questionnaire resulted in a long and unwieldy instrument

The study reported in this chapter tested the hypothesis that it would be feasible to develop a valid and reliable instrument for estimating the prognosis of non specific low back pain from within the biopsychosocial domain, suitable for routine clinical use.

Ethical approval for each step of the instrument's development was obtained from the ethics committee, University of Queensland, Australia.

The components of the resultant instrument (termed the Biopsychosocial Index of Prognosis (BPIP)) were developed from the literature review and perspective of a logical course of clinical enquiry into the current and past episodes of low back pain. The nature and character of the pain together with the severity, spread and duration of the symptoms were also included in the draft questionnaire. Past and present medical and psychological histories were considered together with demographic details including occupation. The items generated were combined into a content map derived from the International Classification of Function (ICF). Initial item generation included items from previously validated instruments identified from the literature where possible. The draft index initially contained 145 items. The large pool of items were initially included in the prototype questionnaire, which was progressively and systematically subjected to item reduction. The necessity for this process of item reduction was established a priori, and driven by the lack of feasibility of carrying a large number of potentially redundant items through to the validation stage of the instruments development (Bellamy, Campbell et al. 2002). The development of the BPIP potentially filled a gap in measurement, estimating prognosis from a variety of biopsychosocial domains and driven by clinical, rather than theoretical perspectives.

Thie chapter describes the development of the BPIP including the steps taken in item reduction and reports on testing the validity of the final instrument, and its reliability against the 'gold standard' measure identified as the Roland and Morris disability questionnaire (RDQ) (Roland and Morris. 1983). The RDQ is one of the most frequently reported instruments used to assess the disability associated with low back pain. The RDQ was also the criterion measure selected for the previous work of Burton and co-workers on psychosocial predictors (Burton, Tillotson, Main and Hollis 1995). A variety of other instruments were considered from the literature including the Orebro Musculoskeletal Pain Questionnaire (Linton and Hallden. 1998) as the potential gold standard. However the focus was on the wider community with low back pain, not just workers with acute low back pain, so the RDQ remained the instrument of choice.

#### **2. Methods**

72 Low Back Pain

There has been increasing acceptance that psychosocial factors play a significant role in the transition from an acute episode, or episodes, of low back pain to a chronic disorder(Pincus, Burton, et al. 2002). There is also some evidence that these factors may play an aetiological

The acceptance of the wider biopsychosocial model has been further extended by the World Health Organisation's (WHO) International Classification of Functioning, Disability and

Many individual psychological factors have been reported over the years as potential obstacles to recovery, with much of the early work centred around fear. Initially the work focussed around the fear avoidance model of exaggerated pain perception in chronic low back develpoed by Lethem and co-workers (Lethem, Slade, Troup, Bentley. 1983). The Fear-Avoidance Belief Questionnaire developed by Waddell and co-workers published in 1993 measured beliefs about physical activity and work (Waddell, Somerville, Henderson, Newton, Main 1993). Workers with low back pain were shown to believe that physical activity including work was feared to increase both spinal pain and damage. These fear avoidant beliefs helped to explain self reported disability in normal daily activities including

Fear of pain together with fear of hurt or harm were further postulated as a fundemental mechanism of disability associated with low back pain were explored by Vlaeyen and Linton. The natural human reaction to pain is an automatic one to try and avoid what is belived to be the cause of the pain, ongoing fear then potentially drives further avoidant

Contrary to the weight of evidence however, surveys of primary contact practitioners continue to indicate that general practitioners for instance, may only be partially managing low back pain from this evidence-based perspective. This may be due in part to the difficulties reported in changing physician behaviour (Buchbinder, Staples et al. 2009) and then further highlighted by the difficulty reported in integrating the biopsychosocial model into clinical disiplines, such as physiotherapy (Harland and Lavallee. 2003). The potential difficulties in fully incorporating a biopsychosocial approach to patients, appear to transcend professional training and boundaries, as Harding and co-workers reported in 2010. Whilst pain clinic practioners in the UK embrase behavioural based management as part of a biopsychosocial pain management model, little consideration was given to social

The estimation of prognosis (identifying those at risk of a poor outcome such as ongoing pain or disability, or failing to return to work) of an episode of low back pain is particularly important to clinicians, patients, employers and third party payers alike. However despite the weight of evidence there remains a tendancy to rely on instruments that quantify prognostic factors from a biomedical perspective alone, rather than the contemporary biopsychosocial model, whilst focusing on return to work as a single outcome. A predictive instrument that may help clinicians fully incorporate the biopsychosocial model into clinical practice clearly has some utility, and whilst it has been suggested that such an instrument needs to capture all the potential biopsychosocial risk factors that may adversely affect functional outcomes (Hilficker, Bachmann, et al. 2007), an initial attempt to produce such a

role (Pincus et al. 2002) (Linton. 2000) (Trouchon, and Fillion. L.2000).

Health (ICF) (WHO. 2000).

work( Waddell et al 1993).

behavior(Vlaeyen and Linton 2000).

factors (Harding, Campbell et al 2010).

draft questionnaire resulted in a long and unwieldy instrument

#### **2.1 Development of the BPIP**

The initial assessments of the prototype index were undertaken in three distinct phases In phase one, piloting was undertaken with a small group without low back pain, consisting of five health care professionals from a variety of disciplines and from different English spreaking countries including England, Australia and New Zealand. and chosen for their academic and general life experiance. The primary focus of the first pilot trial was to obtain feedback on the pool of items selected for evidence of any ambiguity or repetition, ease of administration and the overall comprehensiveness of the questionnaire.

Estimation of Prognosis in Non Specific Low Back Pain from Biopsychosocial Perspectives 75

A 24 hour test-retest of the stability of the ninety-nine item questionnaire was undertaken by twenty five respondents who were asked to complete the first questionnaire (A) and then the second (B) at the same time twenty four hours later, without referring back to their

Questionnaire packs containing the prototype BPIP, RDQ , an informed consent form and instruction sheet were assembled. The data captured at baseline and twelve weeks, outcomes at twelve weeks having been previously reported as being predictive of outcome

Recruitment of respondents originally intended to capture a homogeneous cohort drawn from general practice proved impossible despite repeated requests via the faculty of Health Sciences, University of Queensland. Recruitment difficulties therefore resulted in two distinct cohorts, a larger Australian cohort (*n* = 91) recruited from an osteopathic practice and a diagnostic imaging centre. The smaller New Zealand cohort (*n* = 27) was recruited

The larger Australian group was utilised as an elucidation (or clarification) cohort, and the smaller New Zealand cohort was treated as a small prospective validation of the final

The continued process of item reduction, including correlation analysis of baseline BPIP data with the 12 week score on the RDQ resulted in an ordinal scale of initially 24 items, which was further reduced to 12 items for correlation with the RDQ. The BPIP was tested

The baseline data from the Australian cohort were assessed for concurrent, predictive and

Reliability of the index was evaluated by calculation of Cronbach's Alpha of the baseline BPIP score with the twelve week score on the RDQ in the both cohorts. The mean scores fell within the range of possible scores indicating that the scores were entered into the data set

The BPIP baseline data from the New Zealand cohort was treated as a small prospective validation of the BPIP scale, with the baseline data from the BPIP correlated with the change

The questions retained their original numbers from the draft questionnaire until item

The results are reported in the same order as they contributed to the item reduction process,

reduction was completed, and were then renumbered 1-12 in the final BPIP scale. Analysis was undertaken using the Statistical Package for Social Sciences (SPSS).

previous answers.

**2.2 Data collection** 

version of the BPIP.

correctly.

**3. Results** 

**2.3 Statistical analysis** 

construct validity against the RDQ.

score from the baseline to twelve weeks of the RDQ.

and final assessment of the 12 item BPIP

at one year and beyond (Burton, McClune, et al .2004)

from an osteopathic practice and an osteopathic teaching clinic.

for internal consistency in both the Australian and New Zealand cohorts.

In phase two, a further pilot study was undertaken with a group of low back pain patients recruited from a variety of primary health care practices on the Sunshine Coast in Australia. Patients were provided with a pack containing the prototype questionnaire, and instruction sheet and two copies of the informed consent form together with two stamped addressed envelopes. Each stage of data collection was subjected to ethical clearance through The University of Queensland's ethics committee.

Phase three was a 24 hour test-retest of the reliability of the amended instrument was completed. BPIP packs containing 2 identical questionniares were distributed with the instruction to complete the first questionniare and then the second one, ideally at the same time of day, 24 hours later without reference to the answers provided the day before. The intention was to establish reliability in a sample of 25% of the total of respondents required for the trial of the main instrument.

No specific exclusion criteria were stated other than children or adolescents, pregnancy or three months post partum. The instrument was designed for use in adults over the age of 18 years with English as a first language.

The overall development process of the BPIP is summarised in Figure 1

BPIP item generation ↓ Draft Index ↓ (Prototype BPIP) BPIP item reduction ↓ Reliability (test re-test) ↓ BPIP item reduction ↓ Reliability & validity elucidation (Australian) sample ↓ Reliability & validity confirmation (New Zealand) sample

Fig. 1.

A total of one hundred and forty five items were generated from the literature review and clinical perspectives for the draft questionnaire. Redundant and non response items were eliminated following consultation with a panel of five independent healthcare practitioners as the first stage of item reduction. The questionnaire was subsequently reduced to a ninety nine item prototype.

A 24 hour test-retest of the stability of the ninety-nine item questionnaire was undertaken by twenty five respondents who were asked to complete the first questionnaire (A) and then the second (B) at the same time twenty four hours later, without referring back to their previous answers.

#### **2.2 Data collection**

74 Low Back Pain

In phase two, a further pilot study was undertaken with a group of low back pain patients recruited from a variety of primary health care practices on the Sunshine Coast in Australia. Patients were provided with a pack containing the prototype questionnaire, and instruction sheet and two copies of the informed consent form together with two stamped addressed envelopes. Each stage of data collection was subjected to ethical clearance through The

Phase three was a 24 hour test-retest of the reliability of the amended instrument was completed. BPIP packs containing 2 identical questionniares were distributed with the instruction to complete the first questionniare and then the second one, ideally at the same time of day, 24 hours later without reference to the answers provided the day before. The intention was to establish reliability in a sample of 25% of the total of respondents required

No specific exclusion criteria were stated other than children or adolescents, pregnancy or three months post partum. The instrument was designed for use in adults over the age of 18

> BPIP item generation ↓ Draft Index ↓ (Prototype BPIP) BPIP item reduction ↓ Reliability (test re-test) ↓ BPIP item reduction ↓ Reliability & validity elucidation (Australian) sample ↓ Reliability & validity confirmation (New Zealand) sample

A total of one hundred and forty five items were generated from the literature review and clinical perspectives for the draft questionnaire. Redundant and non response items were eliminated following consultation with a panel of five independent healthcare practitioners as the first stage of item reduction. The questionnaire was subsequently reduced to a ninety

The overall development process of the BPIP is summarised in Figure 1

University of Queensland's ethics committee.

for the trial of the main instrument.

years with English as a first language.

Fig. 1.

nine item prototype.

Questionnaire packs containing the prototype BPIP, RDQ , an informed consent form and instruction sheet were assembled. The data captured at baseline and twelve weeks, outcomes at twelve weeks having been previously reported as being predictive of outcome at one year and beyond (Burton, McClune, et al .2004)

Recruitment of respondents originally intended to capture a homogeneous cohort drawn from general practice proved impossible despite repeated requests via the faculty of Health Sciences, University of Queensland. Recruitment difficulties therefore resulted in two distinct cohorts, a larger Australian cohort (*n* = 91) recruited from an osteopathic practice and a diagnostic imaging centre. The smaller New Zealand cohort (*n* = 27) was recruited from an osteopathic practice and an osteopathic teaching clinic.

The larger Australian group was utilised as an elucidation (or clarification) cohort, and the smaller New Zealand cohort was treated as a small prospective validation of the final version of the BPIP.

#### **2.3 Statistical analysis**

The continued process of item reduction, including correlation analysis of baseline BPIP data with the 12 week score on the RDQ resulted in an ordinal scale of initially 24 items, which was further reduced to 12 items for correlation with the RDQ. The BPIP was tested for internal consistency in both the Australian and New Zealand cohorts.

The baseline data from the Australian cohort were assessed for concurrent, predictive and construct validity against the RDQ.

Reliability of the index was evaluated by calculation of Cronbach's Alpha of the baseline BPIP score with the twelve week score on the RDQ in the both cohorts. The mean scores fell within the range of possible scores indicating that the scores were entered into the data set correctly.

The BPIP baseline data from the New Zealand cohort was treated as a small prospective validation of the BPIP scale, with the baseline data from the BPIP correlated with the change score from the baseline to twelve weeks of the RDQ.

The questions retained their original numbers from the draft questionnaire until item reduction was completed, and were then renumbered 1-12 in the final BPIP scale.

Analysis was undertaken using the Statistical Package for Social Sciences (SPSS).

#### **3. Results**

The results are reported in the same order as they contributed to the item reduction process, and final assessment of the 12 item BPIP

Estimation of Prognosis in Non Specific Low Back Pain from Biopsychosocial Perspectives 77

Correlation analysis (used to describe the strength and direction of the linear relationship between the two variables) of the baseline BPIP Australian data with the twelve week RDQ Australian data resulted in reducing the prototype scale to questions which correlated at or above 0.3. Items which correlated below 0.3 were considered too weak for inclusion, and a

Reliability coefficients for internal consistency of the twenty four item BPIP scale were as

A further review of the correlation analysis of the baseline BPIP Australian data with twelve week RDQ Australian data for items that correlated at or above 0.4 resulted in further item reduction of the BPIP to twelve questions. Following this further item reduction, reliability coefficients for internal consistency were calculated and are included in Tables 5 and 6.

Table 5. Inter-item Statistics Baseline BPIP/12 week RDQ; Australian cohort

regression analysis was undertaken to establish levels of statistical significance.

Once it was established that the reduced scale reliably measured the underlying construct,

Regression analysis of the Australian cohort based on the twelve item scale demonstrated that 61.7% of the variance in the RDQ score at twelve weeks was accounted for by the BPIP

The Australian cohort, Cronbach's Alpha = 0.875. The New Zealand cohort, Cronbach's Alpha = 0.776.

scale, with *p* = 0.0005.

total of twenty four questions were retained for further analysis.

The Australian cohort, Cronbach's Alpha = 0.8736. The New Zealand cohort, Cronbach's Alpha = 0.8628.

**3.2 Item reduction and reliability** 

follows:

#### **3.1 Test-re-test of the ninety nine item prototype BPIP**

A positive correlation between A and B questionnaires was demonstrated in a one tailed test, df 11-2 = 9. The Pearson product moment correlation coefficient was calculated in Excel: Pearson r = 0.98, *P* < 0.0005.

The calculation of R2 0.98 x 0.98 = 0.96, demonstrated that 96% of the shared variance between the two test samples was accounted for by the result.

One hundred and eighteen respondents completed the twelve week data collection period. This was comprised of 91 in the Australian cohort and 27 in New Zealand.

The demographics including gender and age, and the percentage make up of the two cohorts are contained in Tables 1 and 2. Table 3 reports on the duration of low back pain measured at baseline in both cohorts.

#### Gender


Table 1.

#### Age Range


Table 2.

#### Australian Cohort Duration of LBP at Baseline


Table 3.

New Zealand Cohort Duration of LBP at Baseline


Table 4.

#### **3.2 Item reduction and reliability**

76 Low Back Pain

A positive correlation between A and B questionnaires was demonstrated in a one tailed test, df 11-2 = 9. The Pearson product moment correlation coefficient was calculated in Excel:

The calculation of R2 0.98 x 0.98 = 0.96, demonstrated that 96% of the shared variance

One hundred and eighteen respondents completed the twelve week data collection period.

The demographics including gender and age, and the percentage make up of the two cohorts are contained in Tables 1 and 2. Table 3 reports on the duration of low back pain

Gender

Age Range

20-29 6 (7%) 3 (11%) 30-39 13 (14%) 6 (22%) 40-49 16 (18%) 5 (19%) 50-59 30 (33%) 7 (26%) 60 + 26 (29%) 6 (22%)

Australian Cohort Duration of LBP at Baseline

Weeks duration 0-2 weeks 3-5 weeks 6-8 weeks 9-11 weeks 12 weeks + Totals 20 15 5 1 50 Percentage 21.9% 16.4% 5.4% 1.0% 54.9%

New Zealand Cohort Duration of LBP at Baseline Weeks duration 0-2 weeks 3-5 weeks 6-8 weeks 9-11 weeks 12 weeks + Totals 13 5 2 0 7 Percentage 48.1% 18.5% 7.4% 0.0% 25.9%

**3.1 Test-re-test of the ninety nine item prototype BPIP** 

between the two test samples was accounted for by the result.

This was comprised of 91 in the Australian cohort and 27 in New Zealand.

AustralianNew Zealand

AustralianNew Zealand

Male Aus: 26 (29%) NZ: 6 (22%) Female Aus: 65 (71%) NZ: 21 (78%)

Pearson r = 0.98, *P* < 0.0005.

measured at baseline in both cohorts.

Table 1.

Table 2.

Table 3.

Table 4.

Correlation analysis (used to describe the strength and direction of the linear relationship between the two variables) of the baseline BPIP Australian data with the twelve week RDQ Australian data resulted in reducing the prototype scale to questions which correlated at or above 0.3. Items which correlated below 0.3 were considered too weak for inclusion, and a total of twenty four questions were retained for further analysis.

Reliability coefficients for internal consistency of the twenty four item BPIP scale were as follows:

The Australian cohort, Cronbach's Alpha = 0.8736.

The New Zealand cohort, Cronbach's Alpha = 0.8628.

A further review of the correlation analysis of the baseline BPIP Australian data with twelve week RDQ Australian data for items that correlated at or above 0.4 resulted in further item reduction of the BPIP to twelve questions. Following this further item reduction, reliability coefficients for internal consistency were calculated and are included in Tables 5 and 6.


Table 5. Inter-item Statistics Baseline BPIP/12 week RDQ; Australian cohort

The Australian cohort, Cronbach's Alpha = 0.875.

The New Zealand cohort, Cronbach's Alpha = 0.776.

Once it was established that the reduced scale reliably measured the underlying construct, regression analysis was undertaken to establish levels of statistical significance.

Regression analysis of the Australian cohort based on the twelve item scale demonstrated that 61.7% of the variance in the RDQ score at twelve weeks was accounted for by the BPIP scale, with *p* = 0.0005.

Estimation of Prognosis in Non Specific Low Back Pain from Biopsychosocial Perspectives 79

Multiple regression analysis was then performed on the Australian cohort to establish the

The results of the analysis of the Australian cohort are presented in Table 7, Table 8 contains

a. Predictors: (Constant), q74, q26, q69, severity, soclimit, q73, q24, q19, SocIntrude,q25, WorkIntrude,

The variance in the RDQ score (61.7%) at 12 weeks was accounted for by the 12 item BPIP. The null hypothesis that multiple R in this population equals zero was also confirmed by significance in the ANOVA *p* = 0.0005. Multiple R is a measure of how strongly or weakly the criterion variables (BPIP variables) are related to the dependant variable (RDQ)(Stalin.

Regression analysis of the 12 item BPIP with the RDQ change scores baseline to 12 weeks was then performed on the New Zealand cohort, as part of the prospective validation of the

Table 9. Multiple Regression of 12 Item BPIP scores with the change score Roland Morris

Disability Index, baseline to 12 weeks; New Zealand Cohort

predictive value of the shortened BPIP scale score at baseline for the 12 week RDQ.

the ANOVA result which demonstrates levels of significance.

WorkLimit

Table 8.

2003).

b. Dependent Variable: RDQ12wk aus

**3.4 Regression analysis, (New Zealand cohort)** 


Table 6. Inter-Item statistics Baseline BPIP/12 week RDQ; New Zealand cohort

Regression analysis of the change score of the RDQ with the twelve item BPIP in the New Zealand cohort demonstrated that 78.2% of the variance in RDQ scores was accounted for by the BPIP scale, with *p* = 0.006.

#### **3.3 Mulitiple regression analysis (Australian cohort)**

Standard multiple regression analysis was undertaken as it allows for a more sophisticated examination of the relationship between the dependent and independent variables, in this case how well the BPIP was able to predict outcome of the RDQ.


Table 7. Multiple Regression; Australian cohort: Baseline 12 Item BPIP/12 wk RDQ.

Multiple regression analysis was then performed on the Australian cohort to establish the predictive value of the shortened BPIP scale score at baseline for the 12 week RDQ.

The results of the analysis of the Australian cohort are presented in Table 7, Table 8 contains the ANOVA result which demonstrates levels of significance.


a. Predictors: (Constant), q74, q26, q69, severity, soclimit, q73, q24, q19, SocIntrude,q25, WorkIntrude, WorkLimit

b. Dependent Variable: RDQ12wk aus

Table 8.

78 Low Back Pain

Table 6. Inter-Item statistics Baseline BPIP/12 week RDQ; New Zealand cohort

by the BPIP scale, with *p* = 0.006.

**3.3 Mulitiple regression analysis (Australian cohort)** 

case how well the BPIP was able to predict outcome of the RDQ.

Regression analysis of the change score of the RDQ with the twelve item BPIP in the New Zealand cohort demonstrated that 78.2% of the variance in RDQ scores was accounted for

Standard multiple regression analysis was undertaken as it allows for a more sophisticated examination of the relationship between the dependent and independent variables, in this

Table 7. Multiple Regression; Australian cohort: Baseline 12 Item BPIP/12 wk RDQ.

The variance in the RDQ score (61.7%) at 12 weeks was accounted for by the 12 item BPIP. The null hypothesis that multiple R in this population equals zero was also confirmed by significance in the ANOVA *p* = 0.0005. Multiple R is a measure of how strongly or weakly the criterion variables (BPIP variables) are related to the dependant variable (RDQ)(Stalin. 2003).

#### **3.4 Regression analysis, (New Zealand cohort)**

Regression analysis of the 12 item BPIP with the RDQ change scores baseline to 12 weeks was then performed on the New Zealand cohort, as part of the prospective validation of the


Table 9. Multiple Regression of 12 Item BPIP scores with the change score Roland Morris Disability Index, baseline to 12 weeks; New Zealand Cohort

Estimation of Prognosis in Non Specific Low Back Pain from Biopsychosocial Perspectives 81

Phillips and Gross. 2011) that needs to be considered within the context of the indviduals experiance. Recent studies suggest that perceptions of personal control, pain self efficacy, the acute/chronic timeline and illness identity are distinctive psychological obstacles to recovery in primary care patients with low back pain, with depression, catastrophising and fear avoidance being reported as less significant (Foster, Thomas, Bishop, Dunn and Main.

The approach to data collection was to keep exclusion criteria to a minimum and not discriminate against respondents from the arbitrary time dependent classification of 12

A logical sequence of item reduction resulted in the 24 item BPIP scale, which was assessed both for its validity and reliability in separate cohorts, with a similar and strong result in

The Pearson product moment correlation of the total score of the 24 item BPIP scale at baseline with the 12 week RDQ score demonstrated that the New Zealand scores did not reach statistical levels of significance. The small numbers in the cohort (*n* =27) or the more acute nature of the respondents, (21.9% reported pain of more than twelve weeks duration) may have potentially impacted on the result. However as the two cohorts tested differently, the decision to deal with the two groups as separate cohorts appears to have been justified. The BPIP was shortened to 12 items following further correlation analysis of the Australian cohort's BPIP scores and questions demonstrating the stronger correlation of 0.4 were retained, reducing the scale to a single sheet of A4 paper, potentially improving the scales

To check that the reduced scale could still be considered reliable, reliability analysis using Cronbach's alpha was again undertaken in the Australian cohort. There was no appreciable

There was a small decrease in Cronbach's alpha score in the 12 item BPIP in the New Zealand cohort of 0.09 over the 24 item scale although the scale can still be considered as reliable. The correlation analysis of the items was combined with all the other steps of item reduction, to produce the definitive BPIP scale, which proved to be statistically reliable.

The results demonstrate that a high proportion of the variance in the RDQ score at 12 weeks was accounted for by the 12 item BPIP, and statistically significant. The retained questions appear at the end the chapter. The BPIP question which made the strongest unique contribution to the dependent variable was; 'The pain makes me feel that I can't go on with my normal activities'. The individual's perception of their low back pain being the greatest single contributor to their level of functioning, as measured by the RDQ, and interference with work and between episode limitations at work were the next two strongest single contributors.

Interference with work was the strongest single contributor to predicting the dependent variable, which may be expected when the more acute nature of the New Zealand cohort's low back pain is taken into account. Interestingly the next strongest contributor to the prediction of the dependent variable in the New Zealand cohort was the statement that; 'My

difference in the reliability of the 24-item scale over the much shorter 12-item scale.

2011). These findings being broadly consistent with the content of the BPIP.

weeks between acute and chronic low back pain patients.

**4.1 Summary of key findings** 

clinical utility.

both cases, with alpha value above 0.85.

BPIP following the statistical analysis of the Australian data. The change score from baseline to 12 weeks was utilised as the raw baseline to 12 week score in the New Zealand cohort and did not reach statistical significance. The results are summarised in the same order as the Australian results in Tables 9 and 10.

The variance in the change score from baseline to 12 weeks of the Roland Morris Disability Index (78.2%) was accounted for by the 12 item BPIP.

The null hypothesis that multiple R in this New Zealand population equals zero was also confirmed by significance in the ANOVA *p* = 0.006


a. Predictors: (Constant), Q74, Q69, WorkLimit, q24, SocIntrude, q26, severity, SOCLIMIT, Q73, q19, WorkIntrude, q25

b. Dependent Variable: RDQchange 13

Table 10.

#### **4. Discussion**

The development of the BPIP from the original hypothesis, that it was feasible to develop a biopsychosocial prognostic instrument for eventual use in clinical practice, produced a promising result. The utility of the scale may also enable clinicians to consider the possibility that a slow or poor prognosis may be the result of a number of psychosocial obstacles to recovery being present, rather than assuming that underlying pathophysiologic constraints to recovery are the culprits.

The study built on the seminal study of Burton and co-workers (Burton, Tillotson et al. 1993) which utilised a small number of items from previously validated measures to correlate with the RDQ, to positively demonstrate that psychosocial factors were indeed predictive of outcome. Other biopsychosocial instruments tend to focus on single psychosocial predictors (Hurley, Dusoir. et al 2000) or are designed as screening instruments for identifying those specifically at risk of developing long term incapacity from work such as the Orebro questionnaire (Linton and Hallden. 1997). These instruments also differ from the BPIP in that they primarily focus on screening workers with acute low back pain , rather than the wider patient population often consulted in primary care.

The BPIP was developed from clinical perspectives rather than isolating a single construct such as fear avoidance as a predictive factor of disability. The BPIP's focus is consistant with the current idea of low back pain as a fluctuating and disabling condition (Young, Wasiak, Phillips and Gross. 2011) that needs to be considered within the context of the indviduals experiance. Recent studies suggest that perceptions of personal control, pain self efficacy, the acute/chronic timeline and illness identity are distinctive psychological obstacles to recovery in primary care patients with low back pain, with depression, catastrophising and fear avoidance being reported as less significant (Foster, Thomas, Bishop, Dunn and Main. 2011). These findings being broadly consistent with the content of the BPIP.

The approach to data collection was to keep exclusion criteria to a minimum and not discriminate against respondents from the arbitrary time dependent classification of 12 weeks between acute and chronic low back pain patients.

#### **4.1 Summary of key findings**

80 Low Back Pain

BPIP following the statistical analysis of the Australian data. The change score from baseline to 12 weeks was utilised as the raw baseline to 12 week score in the New Zealand cohort and did not reach statistical significance. The results are summarised in the same order as the

The variance in the change score from baseline to 12 weeks of the Roland Morris Disability

The null hypothesis that multiple R in this New Zealand population equals zero was also

a. Predictors: (Constant), Q74, Q69, WorkLimit, q24, SocIntrude, q26, severity, SOCLIMIT, Q73, q19,

The development of the BPIP from the original hypothesis, that it was feasible to develop a biopsychosocial prognostic instrument for eventual use in clinical practice, produced a promising result. The utility of the scale may also enable clinicians to consider the possibility that a slow or poor prognosis may be the result of a number of psychosocial obstacles to recovery being present, rather than assuming that underlying pathophysiologic constraints

The study built on the seminal study of Burton and co-workers (Burton, Tillotson et al. 1993) which utilised a small number of items from previously validated measures to correlate with the RDQ, to positively demonstrate that psychosocial factors were indeed predictive of outcome. Other biopsychosocial instruments tend to focus on single psychosocial predictors (Hurley, Dusoir. et al 2000) or are designed as screening instruments for identifying those specifically at risk of developing long term incapacity from work such as the Orebro questionnaire (Linton and Hallden. 1997). These instruments also differ from the BPIP in that they primarily focus on screening workers with acute low back pain , rather than the

The BPIP was developed from clinical perspectives rather than isolating a single construct such as fear avoidance as a predictive factor of disability. The BPIP's focus is consistant with the current idea of low back pain as a fluctuating and disabling condition (Young, Wasiak,

Australian results in Tables 9 and 10.

WorkIntrude, q25

**4. Discussion**

to recovery are the culprits.

wider patient population often consulted in primary care.

Table 10.

b. Dependent Variable: RDQchange 13

Index (78.2%) was accounted for by the 12 item BPIP.

confirmed by significance in the ANOVA *p* = 0.006

A logical sequence of item reduction resulted in the 24 item BPIP scale, which was assessed both for its validity and reliability in separate cohorts, with a similar and strong result in both cases, with alpha value above 0.85.

The Pearson product moment correlation of the total score of the 24 item BPIP scale at baseline with the 12 week RDQ score demonstrated that the New Zealand scores did not reach statistical levels of significance. The small numbers in the cohort (*n* =27) or the more acute nature of the respondents, (21.9% reported pain of more than twelve weeks duration) may have potentially impacted on the result. However as the two cohorts tested differently, the decision to deal with the two groups as separate cohorts appears to have been justified.

The BPIP was shortened to 12 items following further correlation analysis of the Australian cohort's BPIP scores and questions demonstrating the stronger correlation of 0.4 were retained, reducing the scale to a single sheet of A4 paper, potentially improving the scales clinical utility.

To check that the reduced scale could still be considered reliable, reliability analysis using Cronbach's alpha was again undertaken in the Australian cohort. There was no appreciable difference in the reliability of the 24-item scale over the much shorter 12-item scale.

There was a small decrease in Cronbach's alpha score in the 12 item BPIP in the New Zealand cohort of 0.09 over the 24 item scale although the scale can still be considered as reliable. The correlation analysis of the items was combined with all the other steps of item reduction, to produce the definitive BPIP scale, which proved to be statistically reliable.

The results demonstrate that a high proportion of the variance in the RDQ score at 12 weeks was accounted for by the 12 item BPIP, and statistically significant. The retained questions appear at the end the chapter. The BPIP question which made the strongest unique contribution to the dependent variable was; 'The pain makes me feel that I can't go on with my normal activities'. The individual's perception of their low back pain being the greatest single contributor to their level of functioning, as measured by the RDQ, and interference with work and between episode limitations at work were the next two strongest single contributors.

Interference with work was the strongest single contributor to predicting the dependent variable, which may be expected when the more acute nature of the New Zealand cohort's low back pain is taken into account. Interestingly the next strongest contributor to the prediction of the dependent variable in the New Zealand cohort was the statement that; 'My

research.

**5. Conclusion** 

other populations in future research.

evidence-based 'best practice'.

0 equals no pain, and 10 equal's worst pain.

housework) over the last 7 days? *Please circle one answer* 

*Please circle one answer* 

**6. 12-Item BPIP** 

over the last 7 days?

Estimation of Prognosis in Non Specific Low Back Pain from Biopsychosocial Perspectives 83

The difficulties in recruitment of respondants may also be considered a limiting factor to the

The resulting scale will also require alteration to an entirely ordinal scale to be user friendly for routine clincial use. Scales need to be quick and easy to both administer and score to be a useful clinical resource. These issues will need to be addressed and the results confirmed in

Predicting the outcome from an episode of low back pain has previously been reported and described in terms of the uni-dimensional biomedical perspective, rather than the contemporary biopsychosocial model, although it is evident that psychosocial factors or contextual factors can be a major obstacle to recovery. Clinicians are often encouraged to seek further information such as diagnostic imaging when a patient does not meet their expectation for recovery, rather than considering psychosocial obstacles to recovery. Routine clinical measurement as part of prognostication potentially encourages consideration of all the potential variables that may impact on recovery, and contributes to

When psychosocial obstacles are not identified or duly considered in clinical practice, there is clearly a risk that some patients will go on to develop chronic pain and disability. Early identification of poor prognostic factors may potentially help target specific intervention and improve case management, and an objective measure may potentially contribute to this process. The BPIP potentially fills a gap in measurement, as a valid and reliable prognostic instrument, developed from a clinical perspective and intended for routine clinical use,

Q1. Please score the severity of your low back pain as an average over the last 7 days where

0 1 2 3 4 5 6 7 8 9 10 Q2. How much has your low back pain interfered with your normal work (including

Q3. How much has you low back pain interfered with your normal social (inc sport) life

 SD SA Q4. I can only walk short distances because of my low back pain 1 2 3 4 5

following further validation in differing groups of low back pain patients.

Not at all: A little: Quite a bit: A lot: Totally

Not at all: A little: Quite a bit: A lot: Totally

low back pain is dominating my life', with the statement: 'I have no hope of ever getting back to normal activities' the next strongest predictor. Despite the New Zealand group being a more acute group by duration of low back pain reported at baseline, these perceptions, and mal-adaptive cognitions about the low back pain appear to be evident. This suggests that early on in the duration of an episode of low back pain, perception and maladaptive cognitions may well play a part in influencing prognosis, and can be readily quantified by the BPIP.

#### **4.2 Comparison with other studies**

The variance in RDQ scores was accounted for by the 12 item BPIP in the New Zealand cohort, (78.2%) which was considerably higher than the result of Burton and co-workers (Burton et al. 1995). This is potentially a reflection on the wider biopsychosocial domains of the BPIP capturing a greater range of influences on function when correlated against the RDQ. The result was also statistically significant.

The variance in RDQ score accounted for by the BPIP is similarly higher than that reported by Foster and co-workers in 2010. The prospective cohort study of Foster and co-workers of 3019 adults in the UK assessed distinctiveness of psychosocial obstacles to recovery and their multivariate model accounted for 47.7% in variance of RDQ score at 6 months.

A poor perception of outcome, high disability levels, and high self rated pain intensity were also identified as indicators of a poor prognosis in a large inception cohort study reported by Costa and co-workers (Costa, Maher et al.2009). The large cohort demonstrated more than 50% of respondents had not recovered fully from pain or disability after 12 months and highlighted the desirability of an early biopsychosocial estimation of prognosis to inform patient management.

The size of the cohort compared favourably with other predictive instrument studies reported in the literature such as Hurley and co-workers (*n*=118) (Hurley, Dusoir et al 2001) and Stratford and co-workers (*n*=88) (Stratford, Binkley et al. 1996).

#### **4.3 Limitations**

The biopsychosocial model itself is used in a variety of ways within the literature, with any number of interchangeable variables being included from time to time. This makes a definitive statement about the model and which variables to include for statistical analysis somewhat difficult.

There is also some debate about the relative weight that should be attributed to the biomedical or psychosocial dimensions and whether the literature has become too focused on individual aspects of the model, rather than the overall inclusive biopsychosocial concept. However the literature continues to reflect the need for clinicians to be able to consider their patients from a biopsychosocial perspective in order to inform both prognosis and target interventions.

Self-report and perception of the patient's condition has also been identified as being vulnerable to the individual's social experience (Sen.2002).

The sample size also potentially limits the generalisability of the results.

The difficulties in recruitment of respondants may also be considered a limiting factor to the research.

The resulting scale will also require alteration to an entirely ordinal scale to be user friendly for routine clincial use. Scales need to be quick and easy to both administer and score to be a useful clinical resource. These issues will need to be addressed and the results confirmed in other populations in future research.

#### **5. Conclusion**

82 Low Back Pain

low back pain is dominating my life', with the statement: 'I have no hope of ever getting back to normal activities' the next strongest predictor. Despite the New Zealand group being a more acute group by duration of low back pain reported at baseline, these perceptions, and mal-adaptive cognitions about the low back pain appear to be evident. This suggests that early on in the duration of an episode of low back pain, perception and maladaptive cognitions may well play a part in influencing prognosis, and can be readily

The variance in RDQ scores was accounted for by the 12 item BPIP in the New Zealand cohort, (78.2%) which was considerably higher than the result of Burton and co-workers (Burton et al. 1995). This is potentially a reflection on the wider biopsychosocial domains of the BPIP capturing a greater range of influences on function when correlated against the

The variance in RDQ score accounted for by the BPIP is similarly higher than that reported by Foster and co-workers in 2010. The prospective cohort study of Foster and co-workers of 3019 adults in the UK assessed distinctiveness of psychosocial obstacles to recovery and

A poor perception of outcome, high disability levels, and high self rated pain intensity were also identified as indicators of a poor prognosis in a large inception cohort study reported by Costa and co-workers (Costa, Maher et al.2009). The large cohort demonstrated more than 50% of respondents had not recovered fully from pain or disability after 12 months and highlighted the desirability of an early biopsychosocial estimation of prognosis to inform

The size of the cohort compared favourably with other predictive instrument studies reported in the literature such as Hurley and co-workers (*n*=118) (Hurley, Dusoir et al 2001)

The biopsychosocial model itself is used in a variety of ways within the literature, with any number of interchangeable variables being included from time to time. This makes a definitive statement about the model and which variables to include for statistical analysis

There is also some debate about the relative weight that should be attributed to the biomedical or psychosocial dimensions and whether the literature has become too focused on individual aspects of the model, rather than the overall inclusive biopsychosocial concept. However the literature continues to reflect the need for clinicians to be able to consider their patients from a biopsychosocial perspective in order to inform both prognosis

Self-report and perception of the patient's condition has also been identified as being

their multivariate model accounted for 47.7% in variance of RDQ score at 6 months.

and Stratford and co-workers (*n*=88) (Stratford, Binkley et al. 1996).

vulnerable to the individual's social experience (Sen.2002).

The sample size also potentially limits the generalisability of the results.

quantified by the BPIP.

patient management.

**4.3 Limitations** 

somewhat difficult.

and target interventions.

**4.2 Comparison with other studies** 

RDQ. The result was also statistically significant.

Predicting the outcome from an episode of low back pain has previously been reported and described in terms of the uni-dimensional biomedical perspective, rather than the contemporary biopsychosocial model, although it is evident that psychosocial factors or contextual factors can be a major obstacle to recovery. Clinicians are often encouraged to seek further information such as diagnostic imaging when a patient does not meet their expectation for recovery, rather than considering psychosocial obstacles to recovery. Routine clinical measurement as part of prognostication potentially encourages consideration of all the potential variables that may impact on recovery, and contributes to evidence-based 'best practice'.

When psychosocial obstacles are not identified or duly considered in clinical practice, there is clearly a risk that some patients will go on to develop chronic pain and disability. Early identification of poor prognostic factors may potentially help target specific intervention and improve case management, and an objective measure may potentially contribute to this process. The BPIP potentially fills a gap in measurement, as a valid and reliable prognostic instrument, developed from a clinical perspective and intended for routine clinical use, following further validation in differing groups of low back pain patients.

#### **6. 12-Item BPIP**

Q1. Please score the severity of your low back pain as an average over the last 7 days where 0 equals no pain, and 10 equal's worst pain.

0 1 2 3 4 5 6 7 8 9 10

Q2. How much has your low back pain interfered with your normal work (including housework) over the last 7 days?

*Please circle one answer* 

Not at all: A little: Quite a bit: A lot: Totally

Q3. How much has you low back pain interfered with your normal social (inc sport) life over the last 7 days?

*Please circle one answer* 

Not at all: A little: Quite a bit: A lot: Totally

SD SA

Q4. I can only walk short distances because of my low back pain 1 2 3 4 5

Estimation of Prognosis in Non Specific Low Back Pain from Biopsychosocial Perspectives 85

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Lethem, J., Slade, P.D., Troup, J.D.G., and Bentley, G. Outline of a fearavoidance model of exaggerated pain perception.Behavioral Research and Therapy.1983.21:401-408. Linton, S.J and Hallden, K. Risk factors and the natural course of acute and recurrent

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Q11. In between episodes does your back limit what you can do at work?

*Please circle one response* 

Q12. In between episodes does your back limit what you can do socially (inc sport)?

*Please circle one response* 

Not at all: Occasionally: Often: All the time

#### **7. References**


Q5. Everything I do I consider how it will affect my low back pain 1 2 3 4 5 Q6. My low back pain is dominating my life 1 2 3 4 5 Q7. My low back pain disturbs my sleep 1 2 3 4 5 Q8. The pain makes me feel that I can't go on with my normal activities 1 2 3 4 5 Q9. I believe I will get back to my normal level of activities 1 2 3 4 5 Q10. I have no hope of ever getting back to normal activities 1 2 3 4 5

Q11. In between episodes does your back limit what you can do at work?

Not at all: Occasionally: Often: All the time

Q12. In between episodes does your back limit what you can do socially (inc sport)?

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*Please circle one response* 

*Please circle one response* 

**7. References** 

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**1. Introduction** 

(Andersson, 1999; Croft et al., 1999).

**4** 

*Slovenia* 

**Occupational and Environmental Risk Factors for Development of Low Back** 

Nursing was in the past identified as an occupation whose practitioners were at risk of developing low back pain (LBP) (Engkvist et al., 1998; Hoogendoorn et al., 1999; Goldman et al., 2000). Providing nursing care is related to frequent flexion and extension of the body, including manual lifting (Cromie et al., 2000; Elford et al., 2000; Hui et al., 2001; Daynard et al., 2001). Activities connected to lifting and transferring patients represent major physical demands for nursing personnel, which in many cases result in injuries (Marras et al., 1999; Retsas & Pinikahaba, 2000). Some European countries calculate costs related to LBP treatment at around 1% of yearly gross domestic product (van Tulder et al., 1995; Hansson & Hansson, 2005). Among the musculoskeletal disorders, LBP represents the most frequent incident and the most expensive treatment (Balantič & Zupan, 2003, Whiting & Zernicke, 2008). In a German research the cost for a single episode of LBP was estimated to amount approximately to EUR 1300 in medical costs and loss of production (Wenig et al., 2009). The literature estimates that among adults in the general population, 70-85% are believed to experience at least one episode of low back pain at some time during their lifetime

The problem of LBP in nursing has been thoroughly researched and the main risks are known, and measures have been suggested for its prevention. Success was in most cases reported as adhering to a 'zero lift policy' by using assistive devices (Zhuang et al., 1999, 2000; Nelson et al., 2003a; Collins et al., 2004; Menzel et al., 2004, Nelson et al., 2006). However, the problem of awkward body postures remains, as it is difficult to avoid these altogether (Smedley et al., 1995; Elford et al., 2000). Biomechanical research revealed the human effort in manual lifting, change of patient position in bed, patient transfer from bed to wheelchair or stretcher, patient transfer from wheelchair to toilet and vice versa as major risks for developing LBP (Owen & Garg, 1989; Owen et al., 2002). Therefore it seems reasonable that nursing personnel should remain in good physical condition, not being overweight, with a supple and firm body. Although body mass index (BMI) was not clearly

**Pain in Hospital Nursing Personnel** 

Jadranka Stričević1, Zvone Balantič2, Zmago Turk3,

*1Faculty of Health Sciences, University of Maribor, Maribor, 2Faculty of Organisational Sciences, University of Maribor, Kranj,* 

Dušan Čelan3 and Majda Pajnkihar1

*3 University Clinical Center Maribor, Maribor,* 


### **Occupational and Environmental Risk Factors for Development of Low Back Pain in Hospital Nursing Personnel**

Jadranka Stričević1, Zvone Balantič2, Zmago Turk3, Dušan Čelan3 and Majda Pajnkihar1

*1Faculty of Health Sciences, University of Maribor, Maribor, 2Faculty of Organisational Sciences, University of Maribor, Kranj, 3 University Clinical Center Maribor, Maribor, Slovenia* 

#### **1. Introduction**

86 Low Back Pain

World health organisation. (WHO). International classification of functioning, disability and

Young, A.E., Wasiak, R., Phillips, L., and Gross D.P.Workers persepctives on low back pain

recurrence: "It comes and it goes and comes and goes, but it's always there'

health. 2003. World Health Organisation. Geneva.

2011.Pain:152:204-211

Nursing was in the past identified as an occupation whose practitioners were at risk of developing low back pain (LBP) (Engkvist et al., 1998; Hoogendoorn et al., 1999; Goldman et al., 2000). Providing nursing care is related to frequent flexion and extension of the body, including manual lifting (Cromie et al., 2000; Elford et al., 2000; Hui et al., 2001; Daynard et al., 2001). Activities connected to lifting and transferring patients represent major physical demands for nursing personnel, which in many cases result in injuries (Marras et al., 1999; Retsas & Pinikahaba, 2000). Some European countries calculate costs related to LBP treatment at around 1% of yearly gross domestic product (van Tulder et al., 1995; Hansson & Hansson, 2005). Among the musculoskeletal disorders, LBP represents the most frequent incident and the most expensive treatment (Balantič & Zupan, 2003, Whiting & Zernicke, 2008). In a German research the cost for a single episode of LBP was estimated to amount approximately to EUR 1300 in medical costs and loss of production (Wenig et al., 2009). The literature estimates that among adults in the general population, 70-85% are believed to experience at least one episode of low back pain at some time during their lifetime (Andersson, 1999; Croft et al., 1999).

The problem of LBP in nursing has been thoroughly researched and the main risks are known, and measures have been suggested for its prevention. Success was in most cases reported as adhering to a 'zero lift policy' by using assistive devices (Zhuang et al., 1999, 2000; Nelson et al., 2003a; Collins et al., 2004; Menzel et al., 2004, Nelson et al., 2006). However, the problem of awkward body postures remains, as it is difficult to avoid these altogether (Smedley et al., 1995; Elford et al., 2000). Biomechanical research revealed the human effort in manual lifting, change of patient position in bed, patient transfer from bed to wheelchair or stretcher, patient transfer from wheelchair to toilet and vice versa as major risks for developing LBP (Owen & Garg, 1989; Owen et al., 2002). Therefore it seems reasonable that nursing personnel should remain in good physical condition, not being overweight, with a supple and firm body. Although body mass index (BMI) was not clearly

Occupational and Environmental Risk Factors for

for Safety and Health at Work, 2008).

workers (Council Directive 89/391/EEC, 1989).

1990).

et al., 2009; DiMattio et al., 2010).

Development of Low Back Pain in Hospital Nursing Personnel 89

worker's health or safety. In addition, the employer shall take appropriate steps to ensure that any worker assigned to manual transport of loads other than light loads receives, prior to such assignments, adequate training or instruction in working techniques, with a view to safeguarding health and preventing accidents. The Occupational Safety and Health Convention, adopted 22 June 1981, aims to prevent accidents and injury to health arising out of, linked with or occurring in the course of work, by minimising, so far as is reasonably practicable, the causes of hazards inherent in the working environment (European Agency

The European community mandates certain directives in connection with occupational safety, with each member country having the right to implement the directives according to their own means. Member countries can adopt more intense regulations within individual directives, although this is seldom the case due to economic interests to remain competitiveness with Eastern countries. In general, adopted directives are not intended for certain economic branches and are also not directly connected to musculoskeletal disorders; they give general guidelines to improve occupational health and. Council directive 89/391/EEC obligates employers to introduce measures to encourage improvements in the health and safety of workers at work, whereas information, dialogue and balanced participation on health and safety at work must be developed between employers and

Council directive 90/269/EEC was adopted on 29 May 1990 and supplements the general council directive about measures for occupational health and safety (89/391/EEC) on the minimum health and safety requirements for the manual handling of loads where there is a risk, particularly of back injury, to workers. The general provision states that the employer shall take appropriate organizational measures, or shall use the appropriate means, in particular mechanical equipment, in order to avoid the need for the manual handling of loads by workers. In addition, wherever the need for manual handling of loads by workers cannot be avoided, the employer shall organize workstations in such a way as to make such handling as safe and healthy as possible. Assessment must be made, in advance if possible, of the health and safety conditions of the type of work involved, and in particular examinations of the characteristics of loads. Employers must ensure that workers and/or their representatives receive general indications and, where possible, precise information on the weight of a load, and the centre of gravity of the heaviest side when a package is eccentrically loaded. Employers must ensure that in addition workers receive proper training and information on how to handle loads correctly and the risks they might be open to, particularly if these tasks are not performed correctly (Council directive 90/269/EGS,

Several studies have indicated that LBP may contribute to nursing personnel turnover. For example, Owen (2000) found that 20% of nursing personnel had changed jobs at least once due to LBP problems. In a survey conducted with over 43,000 members of nursing personnel in five countries, 17% to 39% reported that they planned to leave their job in the next year due to the physical and psychological demands of the profession (Aiken et al., 2001). These findings are especially alarming given the current shortage of nursing personnel and the increasing need for nursing care projected over the next decades (Massey

associated with LBP in the past, research has since shown that low BMI may also represent a risk (Lagerstrom et al., 1995; Kerr et al., 2001; Smedley et al., 2003). Older research also examined smoking and alcohol consumption and concluded that this might represent some risk (Frymoyer et al., 1980; Kelsey et al., 1984; Bigos et al., 1986; Heliovaara et al., 1987). Following literature reviews by Ferguson and Marras (1997) and Rubin (2007), these authors summarised the risk factors for developing LBP in advanced age as being female, having a lower economic standard, lower education, smoking, frail health, physical work, repeated tasks, awkward body postures, lower job satisfaction, depression, spinal structure and visible spinal anomalies.

The international literature suggested four major solutions to prevent LBP in nursing personnel. While the 'zero lift policy' is the most promising among the four strategies, unfortunately it is also the most expensive, because technical equipment needs to be purchased (Nelson et al., 2006). Technical equipment in nursing care provision is only useful if the amount of needed force to handle the equipment does not exceed the forces that are developed by manual handling and lifting (Santaguida et al., 2005). The other three solutions introduced were manual lifting techniques (Larese & Fiorito, 1994; Daltroy, 1997; Lagerstrom & Hagberg, 1997; Hye-Knudsen et al. 2004; Karahan & Bayraktar, 2004), forming nursing personnel or special workforces into so called 'lift teams' (Charney, 1997) and introducing regular prevention exercising (Linton & van Tulder, 2001; Rainville et al., 2004; Burton et al., 2005; Byrne et al., 2006).

Several studies that researched improvements in LBP development by applying manual lifting techniques showed no positive long-term effects (Larese & Fiorito, 1994; Daltroy, 1997; Lagerstrom & Hagberg, 1997; Nelson et al., 2003b). Many older Asiatic traditional motion techniques are currently revived, introducing new manual lifting techniques to best overcome physical burden. Marras et al. (1999) concluded that the essential problem in using manual lifting techniques is the human factor, where stressful working conditions and unexpected situations may eventually lead to failures. From a financial aspect manual, lifting techniques are most popular as a prevention strategy because they cost least.

Heavy lifting became a legislative issue in the 1970s and 1980s to prevent occupational activities that might harm workers' health. In the USA the National Institute on Safety and Health recommended the maximum spinal compression force should be 3400N for heavy manual lifting or manual transfer (NIOSH, 1981, 1994). Zhuang et al. (1999) showed that in performing manual patient transfer, specifically turning a patient in bed and lifting the patient to a sitting position in bed on average exceeds this recommended limit. This was especially evident in care activities of overweight patients. Additional research on different manual lifting techniques in team work in patients weighing more than 75kg resulted in spinal compression forces over the recommended threshold of 3400N (Winkelmolen et al., 1994). Nursing personnel are by their occupational duties regularly exposed to burdens that exceed these limits.

The International Labour Organisation (ILO) issued two conventions that are more closely connected to nursing care provision, (1) (Maximum Weight Convention) and (2) C155 (Occupational Safety and Health Convention). The Maximum Weight Convention was adopted on 28 June 1967 and states that no worker shall be required or permitted to engage in the manual transport of a load which, by reason of its weight, is likely to jeopardise the

associated with LBP in the past, research has since shown that low BMI may also represent a risk (Lagerstrom et al., 1995; Kerr et al., 2001; Smedley et al., 2003). Older research also examined smoking and alcohol consumption and concluded that this might represent some risk (Frymoyer et al., 1980; Kelsey et al., 1984; Bigos et al., 1986; Heliovaara et al., 1987). Following literature reviews by Ferguson and Marras (1997) and Rubin (2007), these authors summarised the risk factors for developing LBP in advanced age as being female, having a lower economic standard, lower education, smoking, frail health, physical work, repeated tasks, awkward body postures, lower job satisfaction, depression, spinal structure and

The international literature suggested four major solutions to prevent LBP in nursing personnel. While the 'zero lift policy' is the most promising among the four strategies, unfortunately it is also the most expensive, because technical equipment needs to be purchased (Nelson et al., 2006). Technical equipment in nursing care provision is only useful if the amount of needed force to handle the equipment does not exceed the forces that are developed by manual handling and lifting (Santaguida et al., 2005). The other three solutions introduced were manual lifting techniques (Larese & Fiorito, 1994; Daltroy, 1997; Lagerstrom & Hagberg, 1997; Hye-Knudsen et al. 2004; Karahan & Bayraktar, 2004), forming nursing personnel or special workforces into so called 'lift teams' (Charney, 1997) and introducing regular prevention exercising (Linton & van Tulder, 2001; Rainville et al., 2004;

Several studies that researched improvements in LBP development by applying manual lifting techniques showed no positive long-term effects (Larese & Fiorito, 1994; Daltroy, 1997; Lagerstrom & Hagberg, 1997; Nelson et al., 2003b). Many older Asiatic traditional motion techniques are currently revived, introducing new manual lifting techniques to best overcome physical burden. Marras et al. (1999) concluded that the essential problem in using manual lifting techniques is the human factor, where stressful working conditions and unexpected situations may eventually lead to failures. From a financial aspect manual,

Heavy lifting became a legislative issue in the 1970s and 1980s to prevent occupational activities that might harm workers' health. In the USA the National Institute on Safety and Health recommended the maximum spinal compression force should be 3400N for heavy manual lifting or manual transfer (NIOSH, 1981, 1994). Zhuang et al. (1999) showed that in performing manual patient transfer, specifically turning a patient in bed and lifting the patient to a sitting position in bed on average exceeds this recommended limit. This was especially evident in care activities of overweight patients. Additional research on different manual lifting techniques in team work in patients weighing more than 75kg resulted in spinal compression forces over the recommended threshold of 3400N (Winkelmolen et al., 1994). Nursing personnel are by their occupational duties regularly exposed to burdens that

The International Labour Organisation (ILO) issued two conventions that are more closely connected to nursing care provision, (1) (Maximum Weight Convention) and (2) C155 (Occupational Safety and Health Convention). The Maximum Weight Convention was adopted on 28 June 1967 and states that no worker shall be required or permitted to engage in the manual transport of a load which, by reason of its weight, is likely to jeopardise the

lifting techniques are most popular as a prevention strategy because they cost least.

visible spinal anomalies.

Burton et al., 2005; Byrne et al., 2006).

exceed these limits.

worker's health or safety. In addition, the employer shall take appropriate steps to ensure that any worker assigned to manual transport of loads other than light loads receives, prior to such assignments, adequate training or instruction in working techniques, with a view to safeguarding health and preventing accidents. The Occupational Safety and Health Convention, adopted 22 June 1981, aims to prevent accidents and injury to health arising out of, linked with or occurring in the course of work, by minimising, so far as is reasonably practicable, the causes of hazards inherent in the working environment (European Agency for Safety and Health at Work, 2008).

The European community mandates certain directives in connection with occupational safety, with each member country having the right to implement the directives according to their own means. Member countries can adopt more intense regulations within individual directives, although this is seldom the case due to economic interests to remain competitiveness with Eastern countries. In general, adopted directives are not intended for certain economic branches and are also not directly connected to musculoskeletal disorders; they give general guidelines to improve occupational health and. Council directive 89/391/EEC obligates employers to introduce measures to encourage improvements in the health and safety of workers at work, whereas information, dialogue and balanced participation on health and safety at work must be developed between employers and workers (Council Directive 89/391/EEC, 1989).

Council directive 90/269/EEC was adopted on 29 May 1990 and supplements the general council directive about measures for occupational health and safety (89/391/EEC) on the minimum health and safety requirements for the manual handling of loads where there is a risk, particularly of back injury, to workers. The general provision states that the employer shall take appropriate organizational measures, or shall use the appropriate means, in particular mechanical equipment, in order to avoid the need for the manual handling of loads by workers. In addition, wherever the need for manual handling of loads by workers cannot be avoided, the employer shall organize workstations in such a way as to make such handling as safe and healthy as possible. Assessment must be made, in advance if possible, of the health and safety conditions of the type of work involved, and in particular examinations of the characteristics of loads. Employers must ensure that workers and/or their representatives receive general indications and, where possible, precise information on the weight of a load, and the centre of gravity of the heaviest side when a package is eccentrically loaded. Employers must ensure that in addition workers receive proper training and information on how to handle loads correctly and the risks they might be open to, particularly if these tasks are not performed correctly (Council directive 90/269/EGS, 1990).

Several studies have indicated that LBP may contribute to nursing personnel turnover. For example, Owen (2000) found that 20% of nursing personnel had changed jobs at least once due to LBP problems. In a survey conducted with over 43,000 members of nursing personnel in five countries, 17% to 39% reported that they planned to leave their job in the next year due to the physical and psychological demands of the profession (Aiken et al., 2001). These findings are especially alarming given the current shortage of nursing personnel and the increasing need for nursing care projected over the next decades (Massey et al., 2009; DiMattio et al., 2010).

Occupational and Environmental Risk Factors for

& Al-Jarallah 2005; Rubin, 2007).

**2.3 Statistical analysis** 

marked as statistically significant.

**2.4 Ethical considerations** 

Frequent LBP was reported in 458 (78.8%) of cases.

of 0.8, a sample size of n=139 would be needed (Polit, 1996).

**2.2 Sample** 

Development of Low Back Pain in Hospital Nursing Personnel 91

The structured questionnaire was developed according to literature review about occupational risks connected to development of LBP in nursing personnel, for example, as manual patient transfer, frequent lifting and nursing care provision without the use of assistive devices (Ando et al., 2000; Fairbank & Pynsent, 2000; Davidson & Keating, 2002; Trinkoff et al., 2003; Bot et al., 2004). Included were personal characteristics that were considered to have positive or negative effects on LBP, such as being female, physical condition, BMI, preventive exercising, watching TV (Lahad et al., 1994; Ferguson & Marras, 1997; Maher et al., 1999; Trinkoff et al., 2003; Rainville et al., 2004; Burton et al., 2005; Shehab

The sample consisted of nursing personnel from the University Clinical Center Maribor, the second largest Hospital in Slovenia, with 2800 employees and 1500 members of nursing personnel among them. Hospital nursing personnel in Slovenia involves nursing assistants and registered nurses. Nine hundred questionnaires were distributed among the nursing personnel in 2007, 663 (73.7%) were returned and 581 (64.6%) were considered for analysis. Eighty-two (12.4%) returned questionnaires were excluded due to missing data. Data were collected by convenience sampling. The sample size was selected according to stratification of 40 hospital departments. The strategy in general was to survey 30-40% of nursing personnel from each hospital department to achieve better reliability of results. Gender distribution was 489 (84.2%) women and 92 (15.8%) men, mean age was 37.5±8.9 of years.

The sample size was determined by exemplars from international cross-sectional survey studies, which tend to gather a sample of approximately 500 participants. These sample sizes generally suffice for the needs of the statistical analysis and also give better representation of the researched population. For the statistical relevance, according to alpha level (p-value) of 0.05, the number of predictors (degrees of freedom) of 15 and the anticipated medium effect (f2) size of 0.15, in order to achieve desired statistical power level

Sample data was presented by frequency and percentage for categorical variables or by mean value and standard deviation for numerical variables. Median values were calculated to split numerical variables into two groups. Univariate and multivariate statistics for LBP risk was calculated by binary logistic regression. The chi-square (χ2), odds ratio (OR), 95% confidence interval (95%CI) and P-value were calculated. Multivariate binary logistic regression was calculated without a method to omit insignificant variables. Statistical analysis was performed with SPSS 15.0 software (SPSS Inc., Chicago, IL). P-value < 0.05 was

Approval for the study was obtained locally from the Nursing Care Office of the University Clinical Center Maribor. The research participants were informed about the nature of the study and what participation would entail for them, by receiving a printed information

To contribute to the above knowledge, the aim of this research was to examine to which extent the occupational and environmental risk factors influence the development of LBP in hospital nursing personnel. According to literature review our research included some occupational risk factors and also some personal characteristics about life style, which were designated as environmental risk factors. Among the risk factors included were also some that were expected to act as prevention for developing LBP. Potential risk or prevention factors were included in a multivariate statistical analysis to conduct factors that best predict development of LBP. In the discussion and conclusion sections we introduce some ideas, suggestions and considerations how our results could be implicated in clinical practice. We also provide some suggestions for future research.

To search in the international literature for similar research strategies as we had applied, we conducted a very general search of electronic databases about LBP and nursing personnel or occupation, followed by a subsequent review of abstracts to find more specific literature. The search in the electronic databases Medline, CINAHL and ScienceDirect resulted in 144 non-overlapping hits. Search terms 'nursing' and 'low back pain' were used by selecting the period from 1990 to 2010. The inclusion criteria for the literature search were for terms to be found in the title, abstract or keywords. The larger group of hits was related to LBP occupational risks and four articles only included recreation or exercise as potential LBP prevention. Occupational and environmental components of nursing personnel have rarely been analysed at the same time, and Feng et al. (2007) was identified as the only contribution where recreation was considered in the statistical analysis in conjunction with other LBP risks. The literature search was extended beyond 2007 (till end of 2010), where our research design was initial made and also the data gathering concluded, in order to find any up to date scientific advances.

#### **2. Methods**

As a research method a non-experimental approach with a cross-sectional survey and statistical analysis was used.

#### **2.1 Instrument**

A structured questionnaire about LBP included basic demographic and anthropometric characteristics: age, gender, body height and body weight. The second part of the instrument included occupational risk factors: duration of employment in years, duration of employment in the current position in years, frequent manual weight lifting above 10 kg, manual patient transfer and material handling, patient transfer and material handling with assistive devices, availability of height adjustable beds in nursing care provision, treatment of patients in the highest patient classification system category, and hours of daily work at the computer. The third part included physical activities and habits (environmental risk factors): regular exercises to prevent LBP, recreation and sports in youth, recreation and sports at present, and hours of watching television. The question representing the depended variable was how many episodes of LBP respondents experienced during their working career. A list of all measured characteristics is included in table 1. Duration of employment, work at the computer and watching TV were split into two groups by median value. BMI was calculated as quotient of body weight in kilograms and square of body height in metres. Overweight was marked as BMI ≥ 25 kg/m2 (WHO, 2006).

The structured questionnaire was developed according to literature review about occupational risks connected to development of LBP in nursing personnel, for example, as manual patient transfer, frequent lifting and nursing care provision without the use of assistive devices (Ando et al., 2000; Fairbank & Pynsent, 2000; Davidson & Keating, 2002; Trinkoff et al., 2003; Bot et al., 2004). Included were personal characteristics that were considered to have positive or negative effects on LBP, such as being female, physical condition, BMI, preventive exercising, watching TV (Lahad et al., 1994; Ferguson & Marras, 1997; Maher et al., 1999; Trinkoff et al., 2003; Rainville et al., 2004; Burton et al., 2005; Shehab & Al-Jarallah 2005; Rubin, 2007).

#### **2.2 Sample**

90 Low Back Pain

To contribute to the above knowledge, the aim of this research was to examine to which extent the occupational and environmental risk factors influence the development of LBP in hospital nursing personnel. According to literature review our research included some occupational risk factors and also some personal characteristics about life style, which were designated as environmental risk factors. Among the risk factors included were also some that were expected to act as prevention for developing LBP. Potential risk or prevention factors were included in a multivariate statistical analysis to conduct factors that best predict development of LBP. In the discussion and conclusion sections we introduce some ideas, suggestions and considerations how our results could be implicated in clinical practice. We

To search in the international literature for similar research strategies as we had applied, we conducted a very general search of electronic databases about LBP and nursing personnel or occupation, followed by a subsequent review of abstracts to find more specific literature. The search in the electronic databases Medline, CINAHL and ScienceDirect resulted in 144 non-overlapping hits. Search terms 'nursing' and 'low back pain' were used by selecting the period from 1990 to 2010. The inclusion criteria for the literature search were for terms to be found in the title, abstract or keywords. The larger group of hits was related to LBP occupational risks and four articles only included recreation or exercise as potential LBP prevention. Occupational and environmental components of nursing personnel have rarely been analysed at the same time, and Feng et al. (2007) was identified as the only contribution where recreation was considered in the statistical analysis in conjunction with other LBP risks. The literature search was extended beyond 2007 (till end of 2010), where our research design was initial made and also the data gathering concluded, in order to find

As a research method a non-experimental approach with a cross-sectional survey and

A structured questionnaire about LBP included basic demographic and anthropometric characteristics: age, gender, body height and body weight. The second part of the instrument included occupational risk factors: duration of employment in years, duration of employment in the current position in years, frequent manual weight lifting above 10 kg, manual patient transfer and material handling, patient transfer and material handling with assistive devices, availability of height adjustable beds in nursing care provision, treatment of patients in the highest patient classification system category, and hours of daily work at the computer. The third part included physical activities and habits (environmental risk factors): regular exercises to prevent LBP, recreation and sports in youth, recreation and sports at present, and hours of watching television. The question representing the depended variable was how many episodes of LBP respondents experienced during their working career. A list of all measured characteristics is included in table 1. Duration of employment, work at the computer and watching TV were split into two groups by median value. BMI was calculated as quotient of body weight in kilograms and square of body height in metres.

also provide some suggestions for future research.

any up to date scientific advances.

Overweight was marked as BMI ≥ 25 kg/m2 (WHO, 2006).

statistical analysis was used.

**2. Methods** 

**2.1 Instrument** 

The sample consisted of nursing personnel from the University Clinical Center Maribor, the second largest Hospital in Slovenia, with 2800 employees and 1500 members of nursing personnel among them. Hospital nursing personnel in Slovenia involves nursing assistants and registered nurses. Nine hundred questionnaires were distributed among the nursing personnel in 2007, 663 (73.7%) were returned and 581 (64.6%) were considered for analysis. Eighty-two (12.4%) returned questionnaires were excluded due to missing data. Data were collected by convenience sampling. The sample size was selected according to stratification of 40 hospital departments. The strategy in general was to survey 30-40% of nursing personnel from each hospital department to achieve better reliability of results. Gender distribution was 489 (84.2%) women and 92 (15.8%) men, mean age was 37.5±8.9 of years. Frequent LBP was reported in 458 (78.8%) of cases.

The sample size was determined by exemplars from international cross-sectional survey studies, which tend to gather a sample of approximately 500 participants. These sample sizes generally suffice for the needs of the statistical analysis and also give better representation of the researched population. For the statistical relevance, according to alpha level (p-value) of 0.05, the number of predictors (degrees of freedom) of 15 and the anticipated medium effect (f2) size of 0.15, in order to achieve desired statistical power level of 0.8, a sample size of n=139 would be needed (Polit, 1996).

#### **2.3 Statistical analysis**

Sample data was presented by frequency and percentage for categorical variables or by mean value and standard deviation for numerical variables. Median values were calculated to split numerical variables into two groups. Univariate and multivariate statistics for LBP risk was calculated by binary logistic regression. The chi-square (χ2), odds ratio (OR), 95% confidence interval (95%CI) and P-value were calculated. Multivariate binary logistic regression was calculated without a method to omit insignificant variables. Statistical analysis was performed with SPSS 15.0 software (SPSS Inc., Chicago, IL). P-value < 0.05 was marked as statistically significant.

#### **2.4 Ethical considerations**

Approval for the study was obtained locally from the Nursing Care Office of the University Clinical Center Maribor. The research participants were informed about the nature of the study and what participation would entail for them, by receiving a printed information

Occupational and Environmental Risk Factors for

Duration of employment in

Manual patient transfer and

Patient transfer and material

Height adjustable beds in

Treatment of patients in the highest patient classification

Work with the computer ≥2h

Regular exercises to prevent

Recreation and sports at

Nagelkerke R2=0.245

df=15, p<0.001)

system category

employed as nursing personnel (n=123 or 21.2%).

Development of Low Back Pain in Hospital Nursing Personnel 93

handling, height adjustable beds in nursing care provision and watching TV ≥2h per day. LBP incidents were marked as rare if respondents reported none, one or two incidents while

Results of the follow-up multivariate analysis are presented in Table 2. Three risk factors were calculated as independent predictors for development of LBP. Other significant risk factors on the univariate level failed to achieve statistical significance. The prediction quality of the calculated regression model also resulted in statistical significance (χ2 =99.577, df=15,

Risk factor LBP (in %) χ2 OR 95%CI *P-value* 

frequent (n=458)

Age ≥40 y 26.0 53.9 2.0 2.3 0.7-7.2 *0.152*  Female gender 75.6 86.5 3.0 1.7 0.9-3.0 *0.084*  Duration of employment ≥20y 26.8 54.6 0.0 1.1 0.4-3.6 *0.847* 

current position ≥15y 32.5 51.7 0.6 0.8 0.4-1.4 *0.453*  Frequent manual lifting >10kg 43.1 63.5 14.4 2.4 1.5-3.9 *<0.001* 

material handling 10.6 16.2 1.9 1.6 0.8-3.3 *0.166* 

handling with assistive devices 15.4 6.6 1.5 0.6 0.3-1.3 *0.219* 

nursing care provision 28.5 21.8 0.2 0.9 0.5-1.5 *0.638* 

per day 40.7 24.7 3.3 0.6 0.4-1.0 *0.071* 

LBP 27.6 52.0 16.8 2.8 1.7-4.6 *<0.001*  Recreation and sports in youth 60.2 44.3 0.4 0.9 0.5-1.4 *0.539* 

present 37.4 20.3 7.1 0.5 0.3-0.8 *0.008*  Watching TV ≥2h per day 52.8 51.7 0.6 0.8 0.5-1.3 *0.447 BMI ≥25 25.2 39.3 2.9 1.6 0.9-2.6 0.091* 

Table 2. Multivariate analysis of risk factors for development of LBP (model *χ2* =99.577,

According to χ2 values in Table 2, regular exercises to prevent LBP represented the highest risk for development of LBP (OR 2.8, 95%CI 1.7-4.6). This result shows that nursing personnel started with preventive exercises when it was too late and LBP was already developed. In case of rare LBP problems, 72.4% of nursing personnel without frequent LBP

4.1 11.8 1.9 2.0 0.8-5.5 *0.164* 

p<0.001). The regression model explained 24.5% of the original variance.

rare (n=123)

sheet (Puotiniemi & Kyngäs, 2004). Participants were also asked to contact head nurses of the hospital departments for further questions. Participation in the research was voluntary and anonymous. By applying the stratification by hospital departments, anonymity was to some extend compromised or contracted, nevertheless it was still not possible to recognise the individual participants. Items in the questionnaire were very general; they did not included private items, provoke feelings or address intimate relationship. Items that may potentially harm participants or the University Clinical Center Maribor were also not included in the questionnaire.

#### **3. Results**


Fifteen variables in the form of risk factors were included in the analysis (Table 1).

Table 1. Univariate analysis of risk factors for development of LBP

The results of univariate statistics show that three risk factors were not significantly connected to development of LBP. These were manual patient transfer and material

sheet (Puotiniemi & Kyngäs, 2004). Participants were also asked to contact head nurses of the hospital departments for further questions. Participation in the research was voluntary and anonymous. By applying the stratification by hospital departments, anonymity was to some extend compromised or contracted, nevertheless it was still not possible to recognise the individual participants. Items in the questionnaire were very general; they did not included private items, provoke feelings or address intimate relationship. Items that may potentially harm participants or the University Clinical Center Maribor were also not

Fifteen variables in the form of risk factors were included in the analysis (Table 1).

(n=123)

rare

Risk factor LBP (in %) χ2 OR 95%CI *P-value* 

4.1 11.8 5.8 3.2 1.2-8.1 *0.016* 

frequent (n=458)

Age ≥40 y 26.0 53.9 28.4 3.3 2.1-5.2 *<0.001*  Female gender 75.6 86.5 8.3 2.1 1.3-3.4 *0.004*  Duration of employment ≥20y 26.8 54.6 28.1 3.3 2.1-5.1 *<0.001* 

current position ≥15y 32.5 51.7 14.0 2.2 1.5-3.4 *0.001*  Frequent manual lifting >10kg 43.1 63.5 16.3 2.3 1.5-3.4 *<0.001* 

material handling 10.6 16.2 2.3 1.6 0.8-3.1 *0.126* 

handling with assistive devices 15.4 6.6 9.4 0.4 0.2-0.7 *0.002* 

nursing care provision 28.5 21.8 2.4 0.7 0.5-1.1 *0.124* 

per day 40.7 24.7 12.0 0.5 0.3-0.7 *0.001* 

LBP 27.6 52.0 21.9 2.8 1.8-4.4 *<0.001*  Recreation and sports in youth 60.2 44.3 9.6 0.5 0.4-0.8 *0.002* 

present 37.4 20.3 15.1 0.4 0.3-0.7 *<0.001*  Watching TV ≥2h per day 52.8 51.7 <0.1 1.0 0.6-1.4 *0.829 BMI ≥25 25.2 39.3 8.2 1.9 1.2-3.0 0.004* 

The results of univariate statistics show that three risk factors were not significantly connected to development of LBP. These were manual patient transfer and material

Table 1. Univariate analysis of risk factors for development of LBP

included in the questionnaire.

Duration of employment in

Manual patient transfer and

Patient transfer and material

Height adjustable beds in

Treatment of patients in the highest patient classification

Work with the computer ≥2h

Regular exercises to prevent

Recreation and sports at

system category

**3. Results** 

handling, height adjustable beds in nursing care provision and watching TV ≥2h per day. LBP incidents were marked as rare if respondents reported none, one or two incidents while employed as nursing personnel (n=123 or 21.2%).

Results of the follow-up multivariate analysis are presented in Table 2. Three risk factors were calculated as independent predictors for development of LBP. Other significant risk factors on the univariate level failed to achieve statistical significance. The prediction quality of the calculated regression model also resulted in statistical significance (χ2 =99.577, df=15, p<0.001). The regression model explained 24.5% of the original variance.


Nagelkerke R2=0.245

Table 2. Multivariate analysis of risk factors for development of LBP (model *χ2* =99.577, df=15, p<0.001)

According to χ2 values in Table 2, regular exercises to prevent LBP represented the highest risk for development of LBP (OR 2.8, 95%CI 1.7-4.6). This result shows that nursing personnel started with preventive exercises when it was too late and LBP was already developed. In case of rare LBP problems, 72.4% of nursing personnel without frequent LBP

Occupational and Environmental Risk Factors for

contraindications (Burton et al., 2005).

**4.1 Suggestions for future research** 

(1995) exposed some of these problems scientifically.

Development of Low Back Pain in Hospital Nursing Personnel 95

medical costs, staff turnover and other possible negative side effects of LBP development are

Regular prevention exercises to strengthen back and abdominal muscles lead to improved physical strength and relief to the musculoskeletal when lifting manually or needing to use force (Linton & van Tulder, 2001; Burton et al., 2005). Some other studies, however, only partially confirmed that such an approach prevents developing LBP (Lahad et al., 1994; Maher, 2000; Rainville et al., 2004). Nevertheless, improved physical condition is popular and represents a modern life style to reduce the daily stress. LBP prevention should be incorporated in the regular daily working schedule of nursing personnel in particular. There are several possible ways to realise this, but the most important is to gain the support of legislation and employers. In our opinion it would be best if employees could decide on their own which prevention strategy is most suitable for them, considering their abilities and expectations, and in this way employers, for example, would show their contribution with time subsidies (approximately 15-30 minutes daily). It is also very important to consider that prevention activities and especially sports activities can also lead to health

Members of the nursing personnel who are not interested in recreation and sports should not be forced to improve their physical condition in such a way. Nevertheless, only a small effort is needed for significant improvement (Feng et al., 2007). It is our belief that exercises to prevent LBP should be clearly promoted. Employees in Slovenia must participate in various trainings to keep their working licence, but there is no obligation to train how to maintain vitality. The orientation should be on education about physical stressors and routines how to strengthen the musculoskeletal system to at least try to keep the lifelong resistance. Mitchell et al. (2009) suggested that lifestyle and psychological factors associated

The results conducted in this research are much as expected, yet in some cases also surprising, especially that the frequent manual lifting >10kg was the only significant occupational risk factors for development of LBP. Our expectations were oriented towards duration of employment and age as two typical risk factors for any kind of health risk. We also expected that patient transfer and material handling with assistive devices would reduce the risk for developing LBP. At the University Clinical Center Maribor, for example, surgical departments have better technical equipment then internal medical departments. Surgical departments are housed in new buildings with wide corridors and also in patients' rooms there is more space between beds, although conditions differ according to circumstances; usually in winter time there are more injuries. The typical problem in nearly all hospital departments is lack of space around toilet bowls and bath tubs, doors are not wide enough for easy access with wheelchairs or stretchers. These architectural barriers make solutions for a 'zero lift policy' for nursing personnel a far dream. Engkvist et al.

Further research is needed, including the risk factors involved in this research and more precise details about specific manual patient transfer or manual material handling (patient transfer to wheelchair, stretcher or bath tub, repositioning in bed, washing, toileting etc.).

with LBP should begin to be addressed during undergraduate study.

taken into account, then this equation should turn out positive in the long run.

problems were not performing any preventive exercises. The second ranked risk factor was frequent manual lifting >10 kg (OR 2.4, 95%CI 1.5-3.9). Of the nursing personnel who developed LBP on a frequent basis, 63.5% reported that their care activities are connected to frequent manual lifting of considerable weight. The third ranked risk factor was conducted in better physical condition by regular recreation and sports, which reduced the risk for frequent development of LBP (OR 0.5, 95%CI 0.3-0.8). Only 20.3% of the nursing personnel who reported frequent LBP were regularly engaged in recreation and sports; this percentage was considerably lower compared to nursing personnel without recreational and sporting interests.

#### **4. Discussion**

Frequent LBP was reported in 78.8% of cases, which was similar to results in previous studies (Karahan & Bayraktar, 2004). The strongest risk factor for development of LBP was found in the absence of preventive exercises to strengthen back muscles. Nursing personnel may not be aware of LBP risks and start with preventive exercises when it is already too late and LBP episodes become frequent. Exercises to prevent LBP are considered useful although there is little scholarly agreement on the kind of preventive exercising that should be undertaken or which intensity leads to best possible results (Burton et al., 2005; Byrne et al., 2006). In addition, our results indicate that recreation and sports may reduce risk of developing LBP, although the odds ratio was not as evident. Similar results were obtained by Linton and van Tulder (2001) and Burton et al. (2005).

Manual lifting is the best known risk for development of LBP, especially if the weight is considerable, of frequent nature, or both (Marras et al., 1999; Retsas & Pinikahaba, 2000; Bongers et al., 2002). For many years now, the international literature called to implement working rules for reduction of physical stressors on the human body. The best solution to the problem may be the 'zero lift policy' by using assistive devices when providing nursing care (Collins et al., 2004; Nelson et al., 2006). When considering that the manual lifting hazard grows with advancing age and that the retirement age is increasing, reaching retirement without developing LBP may become a challenge for nursing personnel (Engkvist, 2008). Surprisingly, our results did not significantly confirm this, although odds ratio of 2.3 for higher age (≥40) pointed in the same direction. The financial costs of LBP treatment should not be considered only during employment, because in retirement problems usually increase and become chronic (Turk, 2005). In such cases the financial costs for health insurance may turn out to be considerable for the rest of the person's life due to the need for analgesic drugs and physiotherapy.

Improved physical conditions for nursing personnel is not something that the public directly connects with the purpose of nursing care, which is primarily to offer physical and psychosocial help and care to sick and frail people. Society connects nursing care primarily with virtues like solace, attentiveness, empathy etc., and less with physical strength. It is therefore odd to expect from nursing personnel to expose their low backs far beyond recommended thresholds when manually transferring patients. In that manner, the proposal to reduce workload by grouping nursing personnel or employing specialists as lift teams would considerably reduce exposure to low back problems (Charney, 1997), but due to lack of staff or additional staff costs it is difficult to consider either organisation or employment of such teams. Yet, Charney (1997) argued that if sick leave, subsequent insurance and

problems were not performing any preventive exercises. The second ranked risk factor was frequent manual lifting >10 kg (OR 2.4, 95%CI 1.5-3.9). Of the nursing personnel who developed LBP on a frequent basis, 63.5% reported that their care activities are connected to frequent manual lifting of considerable weight. The third ranked risk factor was conducted in better physical condition by regular recreation and sports, which reduced the risk for frequent development of LBP (OR 0.5, 95%CI 0.3-0.8). Only 20.3% of the nursing personnel who reported frequent LBP were regularly engaged in recreation and sports; this percentage was considerably lower compared to nursing personnel without recreational and sporting

Frequent LBP was reported in 78.8% of cases, which was similar to results in previous studies (Karahan & Bayraktar, 2004). The strongest risk factor for development of LBP was found in the absence of preventive exercises to strengthen back muscles. Nursing personnel may not be aware of LBP risks and start with preventive exercises when it is already too late and LBP episodes become frequent. Exercises to prevent LBP are considered useful although there is little scholarly agreement on the kind of preventive exercising that should be undertaken or which intensity leads to best possible results (Burton et al., 2005; Byrne et al., 2006). In addition, our results indicate that recreation and sports may reduce risk of developing LBP, although the odds ratio was not as evident. Similar results were obtained

Manual lifting is the best known risk for development of LBP, especially if the weight is considerable, of frequent nature, or both (Marras et al., 1999; Retsas & Pinikahaba, 2000; Bongers et al., 2002). For many years now, the international literature called to implement working rules for reduction of physical stressors on the human body. The best solution to the problem may be the 'zero lift policy' by using assistive devices when providing nursing care (Collins et al., 2004; Nelson et al., 2006). When considering that the manual lifting hazard grows with advancing age and that the retirement age is increasing, reaching retirement without developing LBP may become a challenge for nursing personnel (Engkvist, 2008). Surprisingly, our results did not significantly confirm this, although odds ratio of 2.3 for higher age (≥40) pointed in the same direction. The financial costs of LBP treatment should not be considered only during employment, because in retirement problems usually increase and become chronic (Turk, 2005). In such cases the financial costs for health insurance may turn out to be considerable for the rest of the person's life due to

Improved physical conditions for nursing personnel is not something that the public directly connects with the purpose of nursing care, which is primarily to offer physical and psychosocial help and care to sick and frail people. Society connects nursing care primarily with virtues like solace, attentiveness, empathy etc., and less with physical strength. It is therefore odd to expect from nursing personnel to expose their low backs far beyond recommended thresholds when manually transferring patients. In that manner, the proposal to reduce workload by grouping nursing personnel or employing specialists as lift teams would considerably reduce exposure to low back problems (Charney, 1997), but due to lack of staff or additional staff costs it is difficult to consider either organisation or employment of such teams. Yet, Charney (1997) argued that if sick leave, subsequent insurance and

by Linton and van Tulder (2001) and Burton et al. (2005).

the need for analgesic drugs and physiotherapy.

interests.

**4. Discussion** 

medical costs, staff turnover and other possible negative side effects of LBP development are taken into account, then this equation should turn out positive in the long run.

Regular prevention exercises to strengthen back and abdominal muscles lead to improved physical strength and relief to the musculoskeletal when lifting manually or needing to use force (Linton & van Tulder, 2001; Burton et al., 2005). Some other studies, however, only partially confirmed that such an approach prevents developing LBP (Lahad et al., 1994; Maher, 2000; Rainville et al., 2004). Nevertheless, improved physical condition is popular and represents a modern life style to reduce the daily stress. LBP prevention should be incorporated in the regular daily working schedule of nursing personnel in particular. There are several possible ways to realise this, but the most important is to gain the support of legislation and employers. In our opinion it would be best if employees could decide on their own which prevention strategy is most suitable for them, considering their abilities and expectations, and in this way employers, for example, would show their contribution with time subsidies (approximately 15-30 minutes daily). It is also very important to consider that prevention activities and especially sports activities can also lead to health contraindications (Burton et al., 2005).

Members of the nursing personnel who are not interested in recreation and sports should not be forced to improve their physical condition in such a way. Nevertheless, only a small effort is needed for significant improvement (Feng et al., 2007). It is our belief that exercises to prevent LBP should be clearly promoted. Employees in Slovenia must participate in various trainings to keep their working licence, but there is no obligation to train how to maintain vitality. The orientation should be on education about physical stressors and routines how to strengthen the musculoskeletal system to at least try to keep the lifelong resistance. Mitchell et al. (2009) suggested that lifestyle and psychological factors associated with LBP should begin to be addressed during undergraduate study.

#### **4.1 Suggestions for future research**

The results conducted in this research are much as expected, yet in some cases also surprising, especially that the frequent manual lifting >10kg was the only significant occupational risk factors for development of LBP. Our expectations were oriented towards duration of employment and age as two typical risk factors for any kind of health risk. We also expected that patient transfer and material handling with assistive devices would reduce the risk for developing LBP. At the University Clinical Center Maribor, for example, surgical departments have better technical equipment then internal medical departments. Surgical departments are housed in new buildings with wide corridors and also in patients' rooms there is more space between beds, although conditions differ according to circumstances; usually in winter time there are more injuries. The typical problem in nearly all hospital departments is lack of space around toilet bowls and bath tubs, doors are not wide enough for easy access with wheelchairs or stretchers. These architectural barriers make solutions for a 'zero lift policy' for nursing personnel a far dream. Engkvist et al. (1995) exposed some of these problems scientifically.

Further research is needed, including the risk factors involved in this research and more precise details about specific manual patient transfer or manual material handling (patient transfer to wheelchair, stretcher or bath tub, repositioning in bed, washing, toileting etc.).

Occupational and Environmental Risk Factors for

**6. References** 

Development of Low Back Pain in Hospital Nursing Personnel 97

increasing need for nursing care of a frail older population must lead to legislation, and to

The LBP problem is very complex one. The battle against spine diseases should include several professions and multidirectional approaches. We see two crucial points where the most important work against LBP in nursing personnel must be executed. First the nursing schools should include the knowledge about spine problems, risk factors and prevention strategies in their educational programme. Second the employers should be aware of costbenefit of LBP prevention and take care of optimal work organisation and ergonomics with proper technical equipment for diminution of heavy physical work of nursing personnel.

Aiken, L.H.; Clarke, S.P.; Sloane, D.M.; Sochalski, J.A.; Busse, R.; Clarke, H.; Giovannetti, P.;

Ando, S.; Ono, Y.; Shimaoka, M.; Hiruta, S.; Hattori, Y.; Hori, F. & Takeuchi, Y. (2000).

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We also propose that future research should include specific types of recreation and sports activities (running, cycling, fitness, hiking etc.) and types of regular exercises to prevent LBP (yoga, Pilates, aerobics, abdominal training, traditional morning exercises etc.). Noninclusion of this data represents some justified self-criticism of our research design and criticism of other similar studies. Results about risk factors are primarily too general and seldom offer precise information which manual lifting activities should be avoided and which recreational, sporting and preventive activities should be fostered.

#### **4.2 Study limitations**

The sample in our research was gathered from a single hospital. However, our literature review showed that several international hospitals face similar problems to those in Slovenia, primarily because of inadequate staffing levels and occupational stress (time distress, physical and psychological fatigue), that consequently cause pain and injuries to nursing personnel (Hollingdale & Warin, 1997; Vasiliadou et al., 1997; Aiken et al., 2001; Smedley et al., 2003; Videman et al., 2005). We believe that the University Clinical Center Maribor represents typical European and international hospitals supplying comprehensive health care services and disease treatments. Therefore, our research sample included nursing personnel from all areas or departments that are determined by international medicine.

A concern represents a possible non-response. From 900 distributed questionnaires, 237 or 26%, remained unevaluated. There is a possibility of impact on the results because we could not included variance of nursing personnel who did not respond to the research. Nevertheless, the response rate of 74% was, according to international literature, very good (Trinkoff et al., 2003).

Given the cross-sectional study design and the collection of data by self-report, these findings must, however, be interpreted with caution, because self-report may reflect denial, deception, or difficulty in recall (Trinkoff et al., 2003).

#### **5. Conclusion**

Because of various health problems in relation to LBP, which may result in absence from work and consequently increased pressure from employers, it seems reasonable that nursing personnel pay more attention how to maintain a healthy spine. Awkward body postures and manual lifting may be difficult to avoid due to the nature of nursing. Little interest from employers to purchase assistive devices and improve working conditions means that it is important for nursing personnel to find their own suitable LBP prevention strategy. For example, preventive exercises can be more physically oriented, such as abdominal training, or be more vigorous like aerobics, yoga or Pilates. Each prevention strategy may lead to some improvement and if there is dissatisfaction it is easy to stop and to try something else.

The international literature is alarmed about the occupational tasks of nursing personnel that involve a heavy physical burden connected to manual patient and material handling. Nursing personnel are pushed into these risky tasks without much consideration about their health risks. Manual patient transfer and lifting of heavy burden is not defined as an occupational duty or task of nursing personnel. The current shortage of nursing personnel who avoid this ever more physically and psychological stressful occupation, and the increasing need for nursing care of a frail older population must lead to legislation, and to employers to search for solutions to improve working environment.

The LBP problem is very complex one. The battle against spine diseases should include several professions and multidirectional approaches. We see two crucial points where the most important work against LBP in nursing personnel must be executed. First the nursing schools should include the knowledge about spine problems, risk factors and prevention strategies in their educational programme. Second the employers should be aware of costbenefit of LBP prevention and take care of optimal work organisation and ergonomics with proper technical equipment for diminution of heavy physical work of nursing personnel.

#### **6. References**

96 Low Back Pain

We also propose that future research should include specific types of recreation and sports activities (running, cycling, fitness, hiking etc.) and types of regular exercises to prevent LBP (yoga, Pilates, aerobics, abdominal training, traditional morning exercises etc.). Noninclusion of this data represents some justified self-criticism of our research design and criticism of other similar studies. Results about risk factors are primarily too general and seldom offer precise information which manual lifting activities should be avoided and

The sample in our research was gathered from a single hospital. However, our literature review showed that several international hospitals face similar problems to those in Slovenia, primarily because of inadequate staffing levels and occupational stress (time distress, physical and psychological fatigue), that consequently cause pain and injuries to nursing personnel (Hollingdale & Warin, 1997; Vasiliadou et al., 1997; Aiken et al., 2001; Smedley et al., 2003; Videman et al., 2005). We believe that the University Clinical Center Maribor represents typical European and international hospitals supplying comprehensive health care services and disease treatments. Therefore, our research sample included nursing personnel from all areas or departments that are determined by international

A concern represents a possible non-response. From 900 distributed questionnaires, 237 or 26%, remained unevaluated. There is a possibility of impact on the results because we could not included variance of nursing personnel who did not respond to the research. Nevertheless, the response rate of 74% was, according to international literature, very good

Given the cross-sectional study design and the collection of data by self-report, these findings must, however, be interpreted with caution, because self-report may reflect denial,

Because of various health problems in relation to LBP, which may result in absence from work and consequently increased pressure from employers, it seems reasonable that nursing personnel pay more attention how to maintain a healthy spine. Awkward body postures and manual lifting may be difficult to avoid due to the nature of nursing. Little interest from employers to purchase assistive devices and improve working conditions means that it is important for nursing personnel to find their own suitable LBP prevention strategy. For example, preventive exercises can be more physically oriented, such as abdominal training, or be more vigorous like aerobics, yoga or Pilates. Each prevention strategy may lead to some improvement and if there is dissatisfaction it is easy to stop and to try something else. The international literature is alarmed about the occupational tasks of nursing personnel that involve a heavy physical burden connected to manual patient and material handling. Nursing personnel are pushed into these risky tasks without much consideration about their health risks. Manual patient transfer and lifting of heavy burden is not defined as an occupational duty or task of nursing personnel. The current shortage of nursing personnel who avoid this ever more physically and psychological stressful occupation, and the

which recreational, sporting and preventive activities should be fostered.

**4.2 Study limitations** 

medicine.

(Trinkoff et al., 2003).

**5. Conclusion** 

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Occupational and Environmental Risk Factors for

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**1. Introduction** 

Labor, and Welfare Ministry, 2006).

patients were widely recognized factors.

**5** 

*Japan* 

**Low Back Pain in Female** 

Hiroharu Kamioka1 and Takuya Honda2 *1Department of Physical and Health Education,* 

*2Department of Physical and Health Education,* 

In recent years, Japan has become a fast-aging population with the greatest longevity in the world. According to the statistics of Japan, the proportion of the elderly aged 65 years or older reached 20.8% in fiscal, and is estimated to reach 39.6% in 2050 (Japanese Health,

In such an aged society, various health issues occur in caregivers in nursing homes. Particularly in female caregivers, high blood pressure (Hosono et al., 2009) and coronary heart disease (Lee et al., 2003) have been reported to be at high risk. Additionally, caregivers have high prevalence rates of low back pain (LBP) and a high incidence of worker's compensation claims for back injuries (Dehlin et al., 1976; Jorgensen et al., 1994; Fujimura et al., 1995). LBP is common in various occupations, its presence being related to activities requiring repetitive lifting and repeated activities for which anomalous postures tend to be adopted (Josephson et al., 1998). Such work characteristics are common among nursing caregivers. The prevalence of LBP in nursing is high in comparison with other occupations and in relation to other types of work (Ahlberg-Hulten et al., 1995). Risk factors include physical work such as manual lifting and transferring of patients, working conditions such as working time and rest during the night shift, and the working environment (Fujimura et al., 1995). Among these factors, exposures to frequent manual lifting and transferring of

On the other hand, for female caregivers, it was reported that dissatisfaction with working conditions and the workplace environment was high (Fujimura et al., 1995), mental stress from work and human relations tended to be high (Ahlberg-Hulten et al., 1995; Failde et al., 2000), and physical fitness elements such as flexibility and muscular strength were low (Kinugasa et al., 1995). Caregivers in nursing homes perform shift work, including night work. In shift workers, a high risk of sleep interruption was reported (Nicholson et al., 1999). A study reported that caregivers who provided care at night suffered from a general

*Faculty of Environmental Science, Tokyo University of Agriculture,* 

> *Graduate School of Education, The University of Tokyo,*

**Caregivers in Nursing Homes** 


### **Low Back Pain in Female Caregivers in Nursing Homes**

Hiroharu Kamioka1 and Takuya Honda2

*1Department of Physical and Health Education, Faculty of Environmental Science, Tokyo University of Agriculture, 2Department of Physical and Health Education, Graduate School of Education, The University of Tokyo, Japan* 

#### **1. Introduction**

102 Low Back Pain

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Germany, *European Journal of Pain,* Vol.13, No.3, (March 2009), pp. 280-286, ISSN

In recent years, Japan has become a fast-aging population with the greatest longevity in the world. According to the statistics of Japan, the proportion of the elderly aged 65 years or older reached 20.8% in fiscal, and is estimated to reach 39.6% in 2050 (Japanese Health, Labor, and Welfare Ministry, 2006).

In such an aged society, various health issues occur in caregivers in nursing homes. Particularly in female caregivers, high blood pressure (Hosono et al., 2009) and coronary heart disease (Lee et al., 2003) have been reported to be at high risk. Additionally, caregivers have high prevalence rates of low back pain (LBP) and a high incidence of worker's compensation claims for back injuries (Dehlin et al., 1976; Jorgensen et al., 1994; Fujimura et al., 1995). LBP is common in various occupations, its presence being related to activities requiring repetitive lifting and repeated activities for which anomalous postures tend to be adopted (Josephson et al., 1998). Such work characteristics are common among nursing caregivers. The prevalence of LBP in nursing is high in comparison with other occupations and in relation to other types of work (Ahlberg-Hulten et al., 1995). Risk factors include physical work such as manual lifting and transferring of patients, working conditions such as working time and rest during the night shift, and the working environment (Fujimura et al., 1995). Among these factors, exposures to frequent manual lifting and transferring of patients were widely recognized factors.

On the other hand, for female caregivers, it was reported that dissatisfaction with working conditions and the workplace environment was high (Fujimura et al., 1995), mental stress from work and human relations tended to be high (Ahlberg-Hulten et al., 1995; Failde et al., 2000), and physical fitness elements such as flexibility and muscular strength were low (Kinugasa et al., 1995). Caregivers in nursing homes perform shift work, including night work. In shift workers, a high risk of sleep interruption was reported (Nicholson et al., 1999). A study reported that caregivers who provided care at night suffered from a general

Low Back Pain in Female Caregivers in Nursing Homes 105

The GRADE Working Group (Atkins et al., 2004) reported that the balance between benefit and harm, quality of evidence, applicability, and the certainty of the baseline risk were all considered in judgments about the strength of recommendations. Adverse events, withdrawals, and cost for intervention were especially important information for researchers and users of clinical practice guidelines, and we present this information with

The literature searches included 352 potentially relevant articles (Figure 1). Abstracts from those articles were assessed and 11 papers were retrieved for further evaluation (checked for relevant literature). Five publications were excluded because they did not meet the

Two review authors selected the summary from each of the structured abstracts.

**2.3.2 Summary of studies and data extraction** 

**2.3.3 Benefit, harm, and withdrawals** 

the description of each article.

eligibility criteria (see Appendix).

Fig. 1. Flowchart of trial process \*reduplication

**3. Results** 

sense of fatigue, physical disorders, and reduced mental energy compared with employed women (Tsukasaki et al., 2006). A systematic review indicated that female caregivers had higher levels of burden and depression, and lower levels of subjective well-being and physical health (Pinquart et al., 2006). Therefore, it is necessary that the issue of health in caregivers in nursing homes should include not only low back pain, but also mental and physical health status, and how to interpret these factors.

There are some exercise interventions for the lumbago patient (Cherkin et al., 1996; Frost et al., 1998; Kuukkanen et al., 1998), but so far there are few randomized controlled trials (RCTs) for caregivers in nursing homes. Furthermore, there is no study that assumed mental and physical health status as secondary outcome measurements. In a recent study (Bowen et al., 2009), there was an effort to attach great importance to the feasibility-like accumulation of evidence. Because the possibility of generalization is a serious matter, we needed to examine an intervention program with a few burdens to caregivers in a realistic care scenario. The objective of this review was to summarize the evidence from RCTs on the prevention and curative effects for LBP, and to suggest the concrete strategy as a future agenda.

#### **2. Methods**

#### **2.1 Criteria for considering studies included in this review**

#### **2.1.1 Types of studies**

Studies were eligible if they were RCTs.

#### **2.1.2 Types of intervention, language, and participant**

Studies included at least one treatment group in which all therapy was applied. The use of medication, exercise, alternative therapies or lifestyle changes are described, and must have been comparable in the groups studied. There was no restriction on the basis of language. In Japan, nursing is definitely distinguished from care but there are many countries in which this is not the case. Therefore nurses and nursing students were included as search terms. Furthermore, this study established the principal objective in relation to female caregivers, but target articles were included even if they had a small number of male caregivers relative to a majority of female caregivers.

#### **2.2 Search methods for studies identification (Bibliographic database)**

We searched the following databases from January 1, 1990 up to July 20, 2011: MEDLINE via PubMed, Web of Science. All searches were performed by a specific searcher (hospital librarian) who was qualified in medical information handling, and who was experienced in searches of clinical trials.

#### **2.3 Review methods**

#### **2.3.1 Selection of trials**

In order to make the final selection of studies for the review, all criteria were applied independently by two authors to the full text of articles that had passed the first eligibility screening. Disagreements and uncertainties were resolved by discussion.

#### **2.3.2 Summary of studies and data extraction**

Two review authors selected the summary from each of the structured abstracts.

#### **2.3.3 Benefit, harm, and withdrawals**

The GRADE Working Group (Atkins et al., 2004) reported that the balance between benefit and harm, quality of evidence, applicability, and the certainty of the baseline risk were all considered in judgments about the strength of recommendations. Adverse events, withdrawals, and cost for intervention were especially important information for researchers and users of clinical practice guidelines, and we present this information with the description of each article.

### **3. Results**

104 Low Back Pain

sense of fatigue, physical disorders, and reduced mental energy compared with employed women (Tsukasaki et al., 2006). A systematic review indicated that female caregivers had higher levels of burden and depression, and lower levels of subjective well-being and physical health (Pinquart et al., 2006). Therefore, it is necessary that the issue of health in caregivers in nursing homes should include not only low back pain, but also mental and

There are some exercise interventions for the lumbago patient (Cherkin et al., 1996; Frost et al., 1998; Kuukkanen et al., 1998), but so far there are few randomized controlled trials (RCTs) for caregivers in nursing homes. Furthermore, there is no study that assumed mental and physical health status as secondary outcome measurements. In a recent study (Bowen et al., 2009), there was an effort to attach great importance to the feasibility-like accumulation of evidence. Because the possibility of generalization is a serious matter, we needed to examine an intervention program with a few burdens to caregivers in a realistic care scenario. The objective of this review was to summarize the evidence from RCTs on the prevention and

Studies included at least one treatment group in which all therapy was applied. The use of medication, exercise, alternative therapies or lifestyle changes are described, and must have been comparable in the groups studied. There was no restriction on the basis of language. In Japan, nursing is definitely distinguished from care but there are many countries in which this is not the case. Therefore nurses and nursing students were included as search terms. Furthermore, this study established the principal objective in relation to female caregivers, but target articles were included even if they had a small number of male caregivers relative

We searched the following databases from January 1, 1990 up to July 20, 2011: MEDLINE via PubMed, Web of Science. All searches were performed by a specific searcher (hospital librarian) who was qualified in medical information handling, and who was experienced in

In order to make the final selection of studies for the review, all criteria were applied independently by two authors to the full text of articles that had passed the first eligibility

curative effects for LBP, and to suggest the concrete strategy as a future agenda.

**2.2 Search methods for studies identification (Bibliographic database)** 

screening. Disagreements and uncertainties were resolved by discussion.

**2.1 Criteria for considering studies included in this review** 

**2.1.2 Types of intervention, language, and participant** 

physical health status, and how to interpret these factors.

**2. Methods** 

**2.1.1 Types of studies** 

Studies were eligible if they were RCTs.

to a majority of female caregivers.

searches of clinical trials.

**2.3 Review methods 2.3.1 Selection of trials**  The literature searches included 352 potentially relevant articles (Figure 1). Abstracts from those articles were assessed and 11 papers were retrieved for further evaluation (checked for relevant literature). Five publications were excluded because they did not meet the eligibility criteria (see Appendix).

Fig. 1. Flowchart of trial process \*reduplication

Low Back Pain in Female Caregivers in Nursing Homes 107

Table 1-b. Summary of articles based on structured abstracts

Six studies met all inclusion criteria, and Table 1 presents the structured abstracts of these six articles. Table 2 provides a brief summary of the six articles. The types of intervention were as follows: multidimensional method (Miyamoto et al., 1998 and Svensson et al., 2008); transfer technique and stress management (Jensen et al., 2006); lumbar support (Roelofs et al., 2007); stretching exercise (Kamioka et al., 2011); and cognitive behavioral theory (Menzel et al., 2006).


Table 1-a. Summary of articles based on structured abstracts

Six studies met all inclusion criteria, and Table 1 presents the structured abstracts of these six articles. Table 2 provides a brief summary of the six articles. The types of intervention were as follows: multidimensional method (Miyamoto et al., 1998 and Svensson et al., 2008); transfer technique and stress management (Jensen et al., 2006); lumbar support (Roelofs et al., 2007); stretching exercise (Kamioka et al., 2011); and cognitive behavioral theory (Menzel

Table 1-a. Summary of articles based on structured abstracts

et al., 2006).


Table 1-b. Summary of articles based on structured abstracts

Low Back Pain in Female Caregivers in Nursing Homes 109

Table 2. Brief summary of six articles


Table 1-c. Summary of articles based on structured abstracts


Table 2. Brief summary of six articles

108 Low Back Pain

Table 1-c. Summary of articles based on structured abstracts

Low Back Pain in Female Caregivers in Nursing Homes 111

(BoutronI et al., 2005) as quality assessments of articles. However, all studies had acceptably clear descriptions. Our study was able to clarify that coping with LBP was extremely

For LBP, it was a surprising fact that only lumbar support showed significant effect (Roelofs et al., 2007). The authors suggested that the experienced benefit (overall good adherence of wearing; 78%) most likely outweighs the discomfort of the device (Figure 2). This device stabilizes the low back directly by letting the trunk work more. However, there is a concern that the muscular strength of the abdominal and back muscles will decrease when subjects continually use the device. Unfortunately, it is not known if this problem could be avoided

Five RCTs did not show the effects of interventions. A well designed RCT (Jensen et al., 2006) tried to evaluate the effectiveness of the Trans Technique Intervention (TTI; Table 3) and the Stress Management Intervention (SMI; Table 4) in reducing LBP, but both program had no effect on LBP status after 2 years. The authors suggested that the important question remain as to whether the lack of improvement in low back health in the active intervention arms is caused by insufficient implementation of the interventions or if it is the intervention itself that failed to produce better low back health. The authors also described a need for discussing other priorities in the prevention of LBP. Female caregivers always have a tight schedule in the workplace, which may be the main reason they are often not able to use the techniques that they learned. Therefore, we assume that even if an intervention program

In another well designed RCT (Svensson et al., 2008), a multidimensional program combining physical training, patient transfer technique and stress management had no preventive effect on LBP prevalence (sickness absence). The authors explained that it was sometimes hard to motivate patients to participate in the multidimensional program. We assume that the lack of motivation and readiness of the participants for the program produced a negative result. The authors emphasize that future studies for LBP should focus on the implementation of intervention programs in order to obtain precise information on

In a RCT based on cognitive behavioral therapy (Menzel et al., 2006), a statistically significant effect was not observed. There was a high dropout rate (50%) in the intervention group. The authors described that the participants either found attending a session at a specific time and day of week difficult or they judged the intervention to be not helpful. We

In our RCT (Kamioka et al., 2011), we evaluated the intervention effect of on-the-job training (OJT; a lecture by an orthopedist and stretching exercise) on caregivers in Japanese nursing homes. Unfortunately, even with conducting one OJT and exercising only six minutes every day, adherence of caregivers was low and there appeared to be few effects of the intervention. In the subgroup analysis for the high adherence group (>3 times per week), lumbago tended to be reduced, but in the low adherence group (3 times per week>) and the control group, it tended to be worse (p=0.068). This overall ineffectiveness could be attributed to poor adherence by the participants, which was also a problem in other trials.

difficult for female caregivers (nurses).

by regulating the timing and duration of use of this device.

produces a lasting effect, continuous reinforcement is necessary.

assume this result was caused by a lack of motivation of the participant.

**4.2 Why other interventions were ineffective** 

participation and adherence.

In the main outcome measurement (for pain-relieving), it was only lumbar support that was statistically significantly effective (Svensson et al., 2008). For the multidimensional interventions, it was only sick absence (Svensson et al., 2008) and exercise habits (Miyamoto et al., 1998) were statistically significantly effective in the secondary outcomes. Withdrawal rates were described in 5 articles, and tended to be high (14-50%). Adverse events were not described in most articles.

Three articles did not provide information on the costs of intervention. For lumbar support, it cost 50-70 euros per one unit (Roelofs et al., 2007). For stretching exercise, it cost 2,000 dollars as an overall training expense (Kamioka et al., 2011). And, for cognitive behavioral intervention, the compensation to a participant of one hour was shown to be 17 dollars (Menzel et al., 2006).

We could not perform a meta-analysis due to the heterogeneity of the RCTs.

#### **4. Discussion**

#### **4.1 Overall evidence**

We did not use the CONSORT 2010 (Moher et al., 2010), example of an extension for trials assessing nonpharmacologic treatments (Boutron et al., 2008), and CLEAR-NPT checklists

Fig. 2. A sample of lumber support for caregivers (made in Hakujuji corporation, Japan)

In the main outcome measurement (for pain-relieving), it was only lumbar support that was statistically significantly effective (Svensson et al., 2008). For the multidimensional interventions, it was only sick absence (Svensson et al., 2008) and exercise habits (Miyamoto et al., 1998) were statistically significantly effective in the secondary outcomes. Withdrawal rates were described in 5 articles, and tended to be high (14-50%). Adverse events were not

Three articles did not provide information on the costs of intervention. For lumbar support, it cost 50-70 euros per one unit (Roelofs et al., 2007). For stretching exercise, it cost 2,000 dollars as an overall training expense (Kamioka et al., 2011). And, for cognitive behavioral intervention, the compensation to a participant of one hour was shown to be 17 dollars

We did not use the CONSORT 2010 (Moher et al., 2010), example of an extension for trials assessing nonpharmacologic treatments (Boutron et al., 2008), and CLEAR-NPT checklists

Fig. 2. A sample of lumber support for caregivers (made in Hakujuji corporation, Japan)

We could not perform a meta-analysis due to the heterogeneity of the RCTs.

described in most articles.

(Menzel et al., 2006).

**4. Discussion** 

**4.1 Overall evidence** 

(BoutronI et al., 2005) as quality assessments of articles. However, all studies had acceptably clear descriptions. Our study was able to clarify that coping with LBP was extremely difficult for female caregivers (nurses).

For LBP, it was a surprising fact that only lumbar support showed significant effect (Roelofs et al., 2007). The authors suggested that the experienced benefit (overall good adherence of wearing; 78%) most likely outweighs the discomfort of the device (Figure 2). This device stabilizes the low back directly by letting the trunk work more. However, there is a concern that the muscular strength of the abdominal and back muscles will decrease when subjects continually use the device. Unfortunately, it is not known if this problem could be avoided by regulating the timing and duration of use of this device.

#### **4.2 Why other interventions were ineffective**

Five RCTs did not show the effects of interventions. A well designed RCT (Jensen et al., 2006) tried to evaluate the effectiveness of the Trans Technique Intervention (TTI; Table 3) and the Stress Management Intervention (SMI; Table 4) in reducing LBP, but both program had no effect on LBP status after 2 years. The authors suggested that the important question remain as to whether the lack of improvement in low back health in the active intervention arms is caused by insufficient implementation of the interventions or if it is the intervention itself that failed to produce better low back health. The authors also described a need for discussing other priorities in the prevention of LBP. Female caregivers always have a tight schedule in the workplace, which may be the main reason they are often not able to use the techniques that they learned. Therefore, we assume that even if an intervention program produces a lasting effect, continuous reinforcement is necessary.

In another well designed RCT (Svensson et al., 2008), a multidimensional program combining physical training, patient transfer technique and stress management had no preventive effect on LBP prevalence (sickness absence). The authors explained that it was sometimes hard to motivate patients to participate in the multidimensional program. We assume that the lack of motivation and readiness of the participants for the program produced a negative result. The authors emphasize that future studies for LBP should focus on the implementation of intervention programs in order to obtain precise information on participation and adherence.

In a RCT based on cognitive behavioral therapy (Menzel et al., 2006), a statistically significant effect was not observed. There was a high dropout rate (50%) in the intervention group. The authors described that the participants either found attending a session at a specific time and day of week difficult or they judged the intervention to be not helpful. We assume this result was caused by a lack of motivation of the participant.

In our RCT (Kamioka et al., 2011), we evaluated the intervention effect of on-the-job training (OJT; a lecture by an orthopedist and stretching exercise) on caregivers in Japanese nursing homes. Unfortunately, even with conducting one OJT and exercising only six minutes every day, adherence of caregivers was low and there appeared to be few effects of the intervention. In the subgroup analysis for the high adherence group (>3 times per week), lumbago tended to be reduced, but in the low adherence group (3 times per week>) and the control group, it tended to be worse (p=0.068). This overall ineffectiveness could be attributed to poor adherence by the participants, which was also a problem in other trials.

Low Back Pain in Female Caregivers in Nursing Homes 113

Figure 3 shows the educational program for prevention of LBP in nursing facility. First, based on transtheoretical model, identification of the stage of the participant is necessary. Second, before the main interventions, researchers should perform a thorough orientation to promote understanding of the program. Included in the contents of the program should be loss and profit for oneself by participating and protecting one's body, and success and failure samples that are easy to understand. However, unfortunately, in spite of such efforts, it is assumed that there are a few caregivers who will be indifferent or refuse to participate. It is important to the orientation to transfer caregivers to more progressive behavior stages. Greater effects from performing main interventions can be expected when a participant is ready and has enough understanding of the program. In addition, the intervention program should be performed repeatedly and continuously. However, in this concept model, cost-benefit is not considered.

Fig. 3. Concrete educational program for prevention of LBP in nursing facility (Kamioka &

Table 5 shows the current evidence (strength of effect) and future research agenda for various interventions. Researchers should present not only the efficacy data, but also any adverse events or harmful phenomena. In particular, they should clarify problems such as muscle weakness caused by wearing lumbar support too often. In various intervention methods, the re-inspection of an effect by an appropriate study design is necessary. It is essential to scientifically explain the mechanism of effect at the same time. Furthermore, in the exercise intervention, it is

**4.3 Future educational program and research agenda** 

**4.3.1 Educational program agenda** 

Honda, 2011)

**4.3.2 Research agenda** 



#### Table 3. Contents of the Transfer Technique Intervention (TTI) (Jansen et al., 2006)


Table 4. Contents of the Stress Management Intervention (SMI) (Jansen et al., 2006)

#### **4.3 Future educational program and research agenda**

#### **4.3.1 Educational program agenda**

112 Low Back Pain

Table 3. Contents of the Transfer Technique Intervention (TTI) (Jansen et al., 2006)

Table 4. Contents of the Stress Management Intervention (SMI) (Jansen et al., 2006)

Figure 3 shows the educational program for prevention of LBP in nursing facility. First, based on transtheoretical model, identification of the stage of the participant is necessary. Second, before the main interventions, researchers should perform a thorough orientation to promote understanding of the program. Included in the contents of the program should be loss and profit for oneself by participating and protecting one's body, and success and failure samples that are easy to understand. However, unfortunately, in spite of such efforts, it is assumed that there are a few caregivers who will be indifferent or refuse to participate. It is important to the orientation to transfer caregivers to more progressive behavior stages. Greater effects from performing main interventions can be expected when a participant is ready and has enough understanding of the program. In addition, the intervention program should be performed repeatedly and continuously. However, in this concept model, cost-benefit is not considered.

Fig. 3. Concrete educational program for prevention of LBP in nursing facility (Kamioka & Honda, 2011)

#### **4.3.2 Research agenda**

Table 5 shows the current evidence (strength of effect) and future research agenda for various interventions. Researchers should present not only the efficacy data, but also any adverse events or harmful phenomena. In particular, they should clarify problems such as muscle weakness caused by wearing lumbar support too often. In various intervention methods, the re-inspection of an effect by an appropriate study design is necessary. It is essential to scientifically explain the mechanism of effect at the same time. Furthermore, in the exercise intervention, it is

Low Back Pain in Female Caregivers in Nursing Homes 115

(Year) Title Reason of

behavioural medicine work site

risk for developing chronic pain

among healthcare workers

Ahlberg-Hulten, G.K.; Theorell, T. and Sigala, F. (1995). Social support, job strain and

Atkins, D.; Best, D.; Briss, P.A.; Eccles, M. et al. (2004). Grading quality of evidence and

Boutron, I.; Moher, D.; Tugwell, P. et al. (2005). A checklist to evaluate a report of a

Boutron, I.; Moher, D.; Altman, D. et al. (2008). Methods and processes of the CONSORT

Bowen, D.J.; Kreuter, M.; Spring, B. et al. (2009). How we design feasibility studies. Am J

Cherkin, D.C.; Deyo, R.A.; Street J.H. et al.(1996). Pitfalls of patient education: limited success of a program for back pain in primary care. Spine, Vol.21, pp. 345-355 Dehlin, O.; Hedenrud, B. and Horal, J. (1976). Back symptoms in nursing aides in a geriatric

Failde, I.; Gonzalez, J.L.; Novalbos, J.P. et al. (2000). Physical and occupational predictive

Frost, H.; Lamb, S.E.; Moffett, J.A.K.; et al. (1998). A fitness programme for patients with

musculoskeltal pain among female health care personnel. Scand J Work Environ

nonpharmacological trial (CLEAR NPT) was developed using consensus. J Clin

group: example of an extension for trials assessing nonpharmacologic treatments.

factors for back pain among employees of a university hospital in southern Spain.

chronic low back pain: 2-year follow-up of a randomized controlled trial. Pain,

back pain

back pain

strength of recommendations. BMJ, Vol. 328, pp.1490-1497

Coordination of primary health care for

Evaluation of a randomized preventive

intervention for public health workers at

Long-term effects of supervised physical training in secondary prevention of low

Back muscle response to sudden trunk loading can be modified by training

Prevenzione dei disturbi del rachide nei lavoratori di un ospedale: intervento multidisciplinare e valutazione di efficacia exclusion

Not nurse or caregivers

Pain of neck, shoulder, and

All employees of a large hospital

Nonrandomiz ed controlled

Nonrandomiz ed controlled

back

trial

trial

**7. Appendix** 

Excusion no.

References to studies excluded in this review

Author. Journal

Eur J Pain (2001)

Eur Spine J (2005)

4 Pedersen MT, et al. Spine (2007)

Med Lav (2009)

Health, Vol. 21, pp.435-439

Epidemiol, Vol. 58, pp.1233-1240

Ann Inter Med, Vol.148, pp.W60-66

hospital. Scand J Rehab Med, Vol.8, pp. 47-53

Prev Med, Vol. 36, pp. 452-457

Occup Med, Vol.50, pp.591-596

Vol.75, pp.273-279

1 Rossignol M, et al. Spine (2000)

2 Dahl JC, et al.

3 Maul I, et al.

5 Porru S, et al.

**8. References** 


necessary to make the details of at exercise kind (contents), frequency, time and the period clear. Researcher must judge whether caregiver can enforce them as adherence practically.

Table 5. Current evidence and future research agenda

#### **4.4 Study limitations**

This study was based on the PRISMA statement (Liberati A et al., 2009) .except for the metaanalysis. However, there were several limitations to the study. Some selection criteria were common across studies, as described above, but bias remained due to differences in eligibility for participation in each study. Publication bias was also a limitation. Although there was no linguistic restriction in the eligibility criteria, we searched studies with only English and Japanese key words. Furthermore, we could not check the references by a hand search. In addition, a nursing job (in a hospital) is essentially different from a care job (in a nursing facility), but, depending on the country, these are approximately similar working institutions. Therefore, an information bias by having included both may exist.

#### **5. Conclusions**

For LBP, it was a surprising fact that only lumbar support showed a significant effect. Female caregivers are always on a tight schedule in the workplace, which may be the main reason they are often not able to use the techniques that they learned. Therefore, we assume that even if an intervention program produces a lasting effect, continuous reinforcement is necessary. Initially, based on a transtheoretical model, identification of the stage of the participant is necessary. Then, prior to the main interventions, researchers should perform a thorough orientation to promote understanding of the program. Contents of the program should include loss and profit for oneself by participating and protecting one's body, and success and failure samples that are easy to understand.

In various intervention methods, re-inspection of the effect from an appropriate study design is necessary. It is essential to scientifically explain the mechanism of the effect at the same time.

#### **6. Acknowledgments**

We would like to express our appreciation to Ms. Makishi M. and Ms. Higashino R. for their cooperation in this study.

#### **7. Appendix**

114 Low Back Pain

necessary to make the details of at exercise kind (contents), frequency, time and the period clear.

This study was based on the PRISMA statement (Liberati A et al., 2009) .except for the metaanalysis. However, there were several limitations to the study. Some selection criteria were common across studies, as described above, but bias remained due to differences in eligibility for participation in each study. Publication bias was also a limitation. Although there was no linguistic restriction in the eligibility criteria, we searched studies with only English and Japanese key words. Furthermore, we could not check the references by a hand search. In addition, a nursing job (in a hospital) is essentially different from a care job (in a nursing facility), but, depending on the country, these are approximately similar working

For LBP, it was a surprising fact that only lumbar support showed a significant effect. Female caregivers are always on a tight schedule in the workplace, which may be the main reason they are often not able to use the techniques that they learned. Therefore, we assume that even if an intervention program produces a lasting effect, continuous reinforcement is necessary. Initially, based on a transtheoretical model, identification of the stage of the participant is necessary. Then, prior to the main interventions, researchers should perform a thorough orientation to promote understanding of the program. Contents of the program should include loss and profit for oneself by participating and protecting one's body, and

In various intervention methods, re-inspection of the effect from an appropriate study design is necessary. It is essential to scientifically explain the mechanism of the effect at the same time.

We would like to express our appreciation to Ms. Makishi M. and Ms. Higashino R. for their

institutions. Therefore, an information bias by having included both may exist.

Researcher must judge whether caregiver can enforce them as adherence practically.

Table 5. Current evidence and future research agenda

success and failure samples that are easy to understand.

**4.4 Study limitations** 

**5. Conclusions** 

**6. Acknowledgments** 

cooperation in this study.


References to studies excluded in this review

#### **8. References**


**1. Introduction** 

an early stage.

**6** 

**The Use of Event-Related Potentials** 

Carine Vossen, Helen Vossen, Wiesje van de Wetering,

Chronic back pain is one of the most common pain syndromes, with a lifetime incidence of 60% to 90%. An important question in the field of chronic pain is how acute pain transits to a chronic pain state: why do some persons develop chronic pain while others do not? Approximately 10% to 20% of patients with chronic low back pain (CLBP) still have persisting complaints after 6 weeks (Bekkering et al., 2003). If more insight is gained into chronification mechanisms and, as a consequence, the ability to predict which individual with acute pain develops chronic pain, it may become possible to intervene in the process at

In acute pain states, pain is often causally related to physical damage, whereas this relationship is less pronounced in chronic pain states. With increasing duration of pain complaints, other factors, such as psychological, cognitive, and environmental factors, are likely to become more involved (Gamsa, 1994). As a result, pain is conceptualized as a multidimensional phenomenon, making pain measurement complex. However, due to the subjective nature of the pain experience, it can not be measured directly. In fact, only derivatives of pain can be measured. The most frequently measured aspect of pain is its intensity. Two often used measures are the Visual Analog Scale (VAS) and Numeric Rating Scale (NRS). Despite some limitations, their psychometric properties have been demonstrated to be adequate (Jensen et al., 1986; Seymour, 1982). To evaluate several other components of pain, pain-related aspects, and risk factors for chronic back pain (such as fear avoidance, inadequate coping strategies, etc.), clinicians use questionnaires. Although many of these instruments provide reliable and valid results (for an overview, see the Handbook of Pain Assessment, edited by Turk & Melzack, 2011), all subjective measures have the potential for several forms of bias (Magnusson et al., 1995). In an attempt to measure relatively unbiased pain responses, a large number of studies in the 70s and 80s investigated the usefulness of psychophysiological recordings. The results of these studies showed that small but significant correlations could be demonstrated between the subjective pain experience on the one hand and skin conductance, heart rate, electromyography, and finger pulse volume on the other (Flor & Meyer, 2011). The most promising results, however, were obtained from experiments studying event (pain)-related potentials (ERPs), a measure that is derived from electroencephalography (EEG). This technique has been used to study

**in Chronic Back Pain Patients** 

Marco Marcus, Jim van Os and Richel Lousberg

*Maastricht University Medical Centre,* 

*The Netherlands* 


### **The Use of Event-Related Potentials in Chronic Back Pain Patients**

Carine Vossen, Helen Vossen, Wiesje van de Wetering, Marco Marcus, Jim van Os and Richel Lousberg *Maastricht University Medical Centre, The Netherlands* 

#### **1. Introduction**

116 Low Back Pain

Fujimura, T.; Yasuda, N. and Ohara, H. (1995). Work-related factors of low back pain among nursing aides in nursing homes for the elderly. J Occup Health, Vol.37, pp.89-98 Health & Welfare Statistics Association of Japan. (2006). Annual Statistical Report of

Hoshino, J.; Hori, Y.; Kondo, T. et al. (2009). Physical and mental health characteristics of female caregivers. Jpn J Public Health, Vol.56, pp.75-86 (in Japanese with English abstract) Jensen, L.D.; Gonge, H.; Jors, E. et al. (2006). Prevention of low back pain in female eldercare workers: randomized controlled work site trial. Spine, Vol.31, pp.1761-1769 Jorgensen, S.; Hein, H.O. and Gyntelberg, F. (1994). Heavy lifting at work and risk of genital

Josephson, M. and Vingard, E. (1998). Workplace factors and care seeking for low-back pain

Kamioka, H.; Okuizumi, H.; Okada, S. et al. (2011). Effectiveness of intervention for low

Kinugasa, T.; Nagasaki, H.; Ito, H. et al. (1995). Effect of physical fitness, sports activities,

Kuukkanen, T. and Malkia, E. (1998). Effects of a three-month active rehabilitation program

Lee, S.; Colditz, G.A.; Berkman, L.F. and Kawachi, I. (2003). Caregiving and risk of coronary

Liberati, A.; Altman, D.G.; Tetzlaff, J. et al. (2009). The PRISMA statement for reporting

Moher, D.; Hopewell, S.; Schulz, K.F.; et al. (2010). CONSORT 2010 explanation and

Nicholson, P.J. and D'Auria D.A.P. (1999). Shift work, health, the working time regulations

Pinquart, M. and Sorensen, S. (2006). Gender differences in caregiver stressors, social

Roelofs, P.D.; Bierma-Zeinstra, S.M.; van Poppel, M.N. et al. (2007). Lumbar supports to

Stensson, A.L.; Stroyer, J.; Ebbehoj, N.E. et al. (2009). Multidimensional intervention and sickness absence in assistant nuring students. Occup Med, Vol.59, pp.563-569 Tsukasaki, K.; Kido, T.; Makimoto, K. et al. (2006). Naganuma R, Ohno M, Sunaga K. The

heart disease in U.S. women. Am J Prev Med, Vol.24, pp.113-119

Traumatol, Vol.41, pp.223-230 (in Japanese with English abstract)

and health assessments. Occup Med, Vol.49, pp. 127-137

Ann Intern Med, Vol.147, pp.685-692

randomization. Environ Health Prev Med, Vol.16, pp.97-105

Vol.40, pp. 151-160 ( in Japanese with English abstract)

prolapse and herniated lumbar disk in assistant nurses. Occup Med,Vol. 44, pp.47-49

among female nursing personnel: MUSIC-Norrtalje Study Group. Scand J Work

back pain in female caregivers in nursing homes: a pilot trial based on multicenter

and aging on low back pain for women working in nursing home. Jpn J Phys Educ,

on psychomotor performance of lower limbs in subjects with low back pain: a controlled study with a nine-month follow-up. Perceptual Motor Skills, Vol.87, pp.

systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration. Ann Intern Med, Vol.151, pp.W65-94 Menzel, N.N. and Robinson, M.E. (2006). Back pain in direct patient care providers: early intervention with cognitive behavioral therapy. Pain Manag Nurs, Vol.7, pp.53-63 Miyamoto, M.; Shirai, Y.; Takeuti, T. et al. (1998). Prospective study for the occurrence of

low-back pain in newly-employed nurses educated at the back school. Orthop Surg

elaboration: updated guidelines for reporting parallel group randomized trials.

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National Health Conditions. pp.8-24 (in Japanese)

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739-753

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P33-45

Chronic back pain is one of the most common pain syndromes, with a lifetime incidence of 60% to 90%. An important question in the field of chronic pain is how acute pain transits to a chronic pain state: why do some persons develop chronic pain while others do not? Approximately 10% to 20% of patients with chronic low back pain (CLBP) still have persisting complaints after 6 weeks (Bekkering et al., 2003). If more insight is gained into chronification mechanisms and, as a consequence, the ability to predict which individual with acute pain develops chronic pain, it may become possible to intervene in the process at an early stage.

In acute pain states, pain is often causally related to physical damage, whereas this relationship is less pronounced in chronic pain states. With increasing duration of pain complaints, other factors, such as psychological, cognitive, and environmental factors, are likely to become more involved (Gamsa, 1994). As a result, pain is conceptualized as a multidimensional phenomenon, making pain measurement complex. However, due to the subjective nature of the pain experience, it can not be measured directly. In fact, only derivatives of pain can be measured. The most frequently measured aspect of pain is its intensity. Two often used measures are the Visual Analog Scale (VAS) and Numeric Rating Scale (NRS). Despite some limitations, their psychometric properties have been demonstrated to be adequate (Jensen et al., 1986; Seymour, 1982). To evaluate several other components of pain, pain-related aspects, and risk factors for chronic back pain (such as fear avoidance, inadequate coping strategies, etc.), clinicians use questionnaires. Although many of these instruments provide reliable and valid results (for an overview, see the Handbook of Pain Assessment, edited by Turk & Melzack, 2011), all subjective measures have the potential for several forms of bias (Magnusson et al., 1995). In an attempt to measure relatively unbiased pain responses, a large number of studies in the 70s and 80s investigated the usefulness of psychophysiological recordings. The results of these studies showed that small but significant correlations could be demonstrated between the subjective pain experience on the one hand and skin conductance, heart rate, electromyography, and finger pulse volume on the other (Flor & Meyer, 2011). The most promising results, however, were obtained from experiments studying event (pain)-related potentials (ERPs), a measure that is derived from electroencephalography (EEG). This technique has been used to study

The Use of Event-Related Potentials in Chronic Back Pain Patients 119

condition, the averaging procedure results in a voltage-by-time graph. When averaging

In Figure 2, a grand average pain-ERP (Cz location) is shown. This ERP was obtained from a paradigm in which subjects received a series of 150 painful and non-painful shocks of 10 ms in duration (Vossen, 2010c). As can be seen from Figure 2, three peaks can be clearly distinguished. The most common way to describe these peaks is by polarity and latency (time in ms after stimulus onset). For instance, the large positive peak between 250 and 300 ms is called P300. There is also a system that numbers the sequence of the peaks; e.g., the second positive peak is called P2. In this ERP, P300 is the second positive peak, and thus, P2 and P300 are abbreviations pointing to the same peak. In ERP experiments, researchers try to explain the meaning of the peaks. Which (stimulus) characteristics or processes are 'responsible' for the amplitude and latency of the peaks? Early peaks, also called 'exogenous' components, are believed to represent stimulus parameters, such as the intensity and other properties of the stimulus. Later components are thought to be representations of 'endogenous' processes, such as attention (Luck, 2005). Further, it is known that (slight) differences in the paradigm that is used (not only with respect to the stimulus but also to instructions, environmental characteristics, time of the day, etc.) result in changes in the ERP. These changes pertain to latency and amplitude effects and even profound morphological changes. It should be noted that an ERP has a high temporal but low spatial resolution. The latter means that it is difficult to draw valid conclusions on the

underlying cerebral source that is generating the electrical activity (Makeig, 2004).

In this section, we will discuss the influence of a variety of stimulus-related and personrelated factors on the pain-ERP. Special attention will be paid to the predictive relationship

ERPs from different persons or conditions, the result is called a grand average.

Fig. 2. Example of a grand average pain-ERP on Cz.

**3. Influences on the pain-evoked potentials** 

of pain-ERPs to the clinical experience of low back pain.

cerebral responses to (non-)noxious stimuli and to gain more insight into the cortical processing of pain. Pain-ERP studies are typically performed in a laboratory setting under strict experimental control. In contrast to the other aforementioned psychophysiological measures, specific ERP components correlate relatively highly with subjective pain estimates (Bromm et al., 1984; Chen et al., 1979; Miltner et al., 1989). In addition, ERPs have been shown to contain information not only on pain intensity but also on many other important (pain-related) factors, such as habituation, personality, and coping strategies. In other words, making use of ERPs, a large number of aspects of the pain construct, interrelations, and mechanisms can be quantified and studied (see Loesers "onion" model in Fig. 1).

Fig. 1. Loesers "onion" model, modified with the addition of the position of questionnaires and event-related potentials.

This chapter starts with a general description of event-related potentials and their components. Second, factors related to the pain-ERP, such as personality and genetics, are discussed. Special attention will be paid to methods of analyzing the ERP signal. After some discussion of methodological considerations, we will propose an alternative ERP analysis. In addition, we will present preliminary data to illustrate the usefulness of this alternative method. In the last section, some future directions of ERP will be discussed.

#### **2. ERP structure**

The ERP represents a cortical response to a specific stimulus—for instance, a sound, a light signal, or a pain stimulus. Event-related potentials are regarded as manifestations of specific (psycho)physiological, stimulus-related processes. An ERP is derived from EEG. Electrodes are attached to specific locations on the scalp (Jasper, 1958). Potential differences between the scalp electrodes and a reference electrode are sampled at a certain frequency, most commonly between 500 and 5000 Hz (cycles per second). The essence of an ERP is that the signal (the cortical reaction to the stimulus) has to be discriminated from background EEG noise. The procedure to achieve this goal is to compute an average of a number of timelocked EEG samples, called epochs or segments. As a general rule, it can be stated that the larger the number of epochs, the better the signal-to-noise ratio. Within each person or

cerebral responses to (non-)noxious stimuli and to gain more insight into the cortical processing of pain. Pain-ERP studies are typically performed in a laboratory setting under strict experimental control. In contrast to the other aforementioned psychophysiological measures, specific ERP components correlate relatively highly with subjective pain estimates (Bromm et al., 1984; Chen et al., 1979; Miltner et al., 1989). In addition, ERPs have been shown to contain information not only on pain intensity but also on many other important (pain-related) factors, such as habituation, personality, and coping strategies. In other words, making use of ERPs, a large number of aspects of the pain construct, interrelations, and mechanisms can be quantified and studied (see Loesers "onion" model in

Fig. 1. Loesers "onion" model, modified with the addition of the position of questionnaires

This chapter starts with a general description of event-related potentials and their components. Second, factors related to the pain-ERP, such as personality and genetics, are discussed. Special attention will be paid to methods of analyzing the ERP signal. After some discussion of methodological considerations, we will propose an alternative ERP analysis. In addition, we will present preliminary data to illustrate the usefulness of this alternative

The ERP represents a cortical response to a specific stimulus—for instance, a sound, a light signal, or a pain stimulus. Event-related potentials are regarded as manifestations of specific (psycho)physiological, stimulus-related processes. An ERP is derived from EEG. Electrodes are attached to specific locations on the scalp (Jasper, 1958). Potential differences between the scalp electrodes and a reference electrode are sampled at a certain frequency, most commonly between 500 and 5000 Hz (cycles per second). The essence of an ERP is that the signal (the cortical reaction to the stimulus) has to be discriminated from background EEG noise. The procedure to achieve this goal is to compute an average of a number of timelocked EEG samples, called epochs or segments. As a general rule, it can be stated that the larger the number of epochs, the better the signal-to-noise ratio. Within each person or

method. In the last section, some future directions of ERP will be discussed.

Fig. 1).

and event-related potentials.

**2. ERP structure** 

condition, the averaging procedure results in a voltage-by-time graph. When averaging ERPs from different persons or conditions, the result is called a grand average.

Fig. 2. Example of a grand average pain-ERP on Cz.

In Figure 2, a grand average pain-ERP (Cz location) is shown. This ERP was obtained from a paradigm in which subjects received a series of 150 painful and non-painful shocks of 10 ms in duration (Vossen, 2010c). As can be seen from Figure 2, three peaks can be clearly distinguished. The most common way to describe these peaks is by polarity and latency (time in ms after stimulus onset). For instance, the large positive peak between 250 and 300 ms is called P300. There is also a system that numbers the sequence of the peaks; e.g., the second positive peak is called P2. In this ERP, P300 is the second positive peak, and thus, P2 and P300 are abbreviations pointing to the same peak. In ERP experiments, researchers try to explain the meaning of the peaks. Which (stimulus) characteristics or processes are 'responsible' for the amplitude and latency of the peaks? Early peaks, also called 'exogenous' components, are believed to represent stimulus parameters, such as the intensity and other properties of the stimulus. Later components are thought to be representations of 'endogenous' processes, such as attention (Luck, 2005). Further, it is known that (slight) differences in the paradigm that is used (not only with respect to the stimulus but also to instructions, environmental characteristics, time of the day, etc.) result in changes in the ERP. These changes pertain to latency and amplitude effects and even profound morphological changes. It should be noted that an ERP has a high temporal but low spatial resolution. The latter means that it is difficult to draw valid conclusions on the underlying cerebral source that is generating the electrical activity (Makeig, 2004).

#### **3. Influences on the pain-evoked potentials**

In this section, we will discuss the influence of a variety of stimulus-related and personrelated factors on the pain-ERP. Special attention will be paid to the predictive relationship of pain-ERPs to the clinical experience of low back pain.

The Use of Event-Related Potentials in Chronic Back Pain Patients 121

measure, reported mixed results. One study investigated the habituation difference between CLBP patients and controls, using eight successive trials of the cold pressure test (Brandt & Schmidt, 1987). Healthy controls could be divided into a subgroup that habituated over trials and a subgroup that sensitized. The CLBP group did not habituate or sensitize over time. Additionally, they found a lower pain tolerance in CLBP patients while reporting higher pain ratings. It was hypothesized that CLBP patients had already undergone a learning process in which sensitization had taken place. Arntz and colleagues (1991) also studied habituation in CLBP patients and controls. They did not observe a difference in habituation between the groups, measured by pain intensity ratings, EMG, and heart rate. A third study (Peters et al., 1989) confirmed the results of Brandt & Schmidt (1987) but did not find differences in physiological measures, such as heart rate and skin conductance. More recently, Smith and colleagues (2008) reported differences in habituation of subjective pain ratings between women with fibromyalgia and pain-free controls. They found that women

In addition, there are some recent studies that have used ERP as a measure to study habituation. They are suggestive of a deficit in habituation in chronic pain patients, although different chronic pain populations were used. Valeriani and colleagues (2003) studied habituation in response to painful CO2 laser stimulation in migraine patients. They found reduced habituation of ERP amplitudes in migraine sufferers compared to pain-free controls. In disconfirmation, another study found that patients with migraine did not show any habituation, whereas healthy controls did (De Tommaso, 2005). Vossen et al. (2010c) studied habituation in a group of chronic low back pain patients compared to pain-free controls, measuring ERP in response to 20 painful stimuli. They found a significant interaction between group and trial number on the P300 component at C4 and T4. This means that chronic low back pain patients appeared to habituate to a lesser degree than pain-free controls. They also examined the influence of state-depression on habituation, using the BDI score. The results revealed a significant three-way interaction between BDI, group, and trialinverse, suggesting that the difference in habituation between groups depends on the level of depression. Only in the presence of depression did CLBP patients show a deficit in habituation. Interestingly, a recent study in fibromyalgia patients also found evidence for reduced habituation of the N200 vertex component, facilitated by the presence of symptoms of depression (De Tommaso, 2011). In conclusion, habituation seems to be different in chronic back pain patients compared to controls but is probably also influenced

"Personality" can be defined as a dynamic and organized set of characteristics possessed by a person that uniquely influence his or her cognitions, motivations, and behaviors in various situations (Ryckman, 2008). Individuals with different personalities will differ in reaction to a specific situation. Likewise, it is conceivable that persons with diverse personality structures will react differently to a pain stimulus. This theoretical claim is frequently being confirmed in clinical practice. There is a large variety in 'pain behaviors' when patients are confronted with painful medical procedures (injections, stitches, etc.). One of the most important personality factors that are known to influence the experience of pain is neuroticism (Wade et al., 1992). Neuroticism is defined as a tendency to experience negative

with fibromyalgia habituated at a lower rate to repeated heat stimuli.

by factors, such as depression.

**3.3 Influence of neuroticism on pain-evoked potentials** 

#### **3.1 Stimulus intensity and subjective pain experience**

Intensity is an essential property of a stimulus. Is there a relationship between the intensity of a stimulus and peaks of the ERP? Accumulating evidence confirms the relationship between stimulus intensity and increased peak values of N200 and P300 (Becker et al., 1993; Bromm & Meier, 1984; Stowell, 1977). Does an increase in certain peak amplitudes relate to the amount of pain that a subject experiences? One of the first studies that investigated this association demonstrated that an increase in the N200 and P300 peak amplitudes was accompanied by an increase in VAS scores (r = 0.67-0.77) (Harkins & Chapman, 1978). These results were replicated by Chen (1979) and Garcia-Larrea (1997). These authors also found a strong linear association (r = 0.67 and r = 0.41, respectively) between the N200/P300 peakto-peak amplitude and subjective pain ratings. Miltner and colleagues (1987), however, could not find such a relationship when investigating habituation of noxious stimuli. They observed a significant decrease in peak-to-peak amplitudes of the N150-P360 across trials, but without a corresponding effect on VAS ratings. They suggested that the association between ERP amplitudes and subjective ratings might not be as strong as was claimed previously.

The subjective pain experience seems to be limited not only to these peak amplitude effects. Kanda and colleagues (2002) discovered a late positive component around 600 ms that was associated with pain report, which they called the 'intensity assessment-related potential' (IAP). The IAP was not influenced by intensity, suggesting that this component solely reflects the psychological processes of pain. A recent study, again investigating the relationship between stimulus intensity, peak amplitudes, and subjective pain experience, was performed by Vossen and colleagues (2011). Their methodological comments on common pain-ERP analyses relate to the problems inherent in the averaging technique (see also paragraph 4). The authors argued that averaging eliminates any unwanted 'noise' in the ERP, but in doing so, it assumes no difference between repeated trials. This assumption can not hold, since single trials likely differ from one another because of processes, such as habituation. Moreover, averaging across trials eliminates all information about possible within-subject correlations between ERP and subjective pain. As an alternative, they introduced multilevel random regression analysis, applied on pain-ERP, making it possible to model time (habituation), stimulus intensity, and their random within-person effects. The findings of this study show that the relationships between these three variables are confounded and moderated by several other variables, such as the intensity of the previous stimulus. This means that a certain pain rating after a stimulus also depends on the intensity of the previous stimulus, which makes clinical sense. A pain patient who is asked to evaluate his/her perceived pain is highly likely to base this evaluation on previous pain experiences. In sum, the relationship between stimulus intensity, ERP peaks, and pain experience is probably far more complex than previously thought.

#### **3.2 Habituation and pain-evoked potentials**

Habituation is the process that refers to a decrease in a behavioral response to a repeatedly presented stimulus (Thompson & Spencer, 1966). It could be hypothesized that altered habituation might be an explanation for the chronification of pain. It is thought that chronic pain patients may have a deficit in habituation or even an inability to habituate to painful experiences, resulting in persistent pain. Older studies, using pain rating as an outcome

Intensity is an essential property of a stimulus. Is there a relationship between the intensity of a stimulus and peaks of the ERP? Accumulating evidence confirms the relationship between stimulus intensity and increased peak values of N200 and P300 (Becker et al., 1993; Bromm & Meier, 1984; Stowell, 1977). Does an increase in certain peak amplitudes relate to the amount of pain that a subject experiences? One of the first studies that investigated this association demonstrated that an increase in the N200 and P300 peak amplitudes was accompanied by an increase in VAS scores (r = 0.67-0.77) (Harkins & Chapman, 1978). These results were replicated by Chen (1979) and Garcia-Larrea (1997). These authors also found a strong linear association (r = 0.67 and r = 0.41, respectively) between the N200/P300 peakto-peak amplitude and subjective pain ratings. Miltner and colleagues (1987), however, could not find such a relationship when investigating habituation of noxious stimuli. They observed a significant decrease in peak-to-peak amplitudes of the N150-P360 across trials, but without a corresponding effect on VAS ratings. They suggested that the association between ERP amplitudes and subjective ratings might not be as strong as was claimed

The subjective pain experience seems to be limited not only to these peak amplitude effects. Kanda and colleagues (2002) discovered a late positive component around 600 ms that was associated with pain report, which they called the 'intensity assessment-related potential' (IAP). The IAP was not influenced by intensity, suggesting that this component solely reflects the psychological processes of pain. A recent study, again investigating the relationship between stimulus intensity, peak amplitudes, and subjective pain experience, was performed by Vossen and colleagues (2011). Their methodological comments on common pain-ERP analyses relate to the problems inherent in the averaging technique (see also paragraph 4). The authors argued that averaging eliminates any unwanted 'noise' in the ERP, but in doing so, it assumes no difference between repeated trials. This assumption can not hold, since single trials likely differ from one another because of processes, such as habituation. Moreover, averaging across trials eliminates all information about possible within-subject correlations between ERP and subjective pain. As an alternative, they introduced multilevel random regression analysis, applied on pain-ERP, making it possible to model time (habituation), stimulus intensity, and their random within-person effects. The findings of this study show that the relationships between these three variables are confounded and moderated by several other variables, such as the intensity of the previous stimulus. This means that a certain pain rating after a stimulus also depends on the intensity of the previous stimulus, which makes clinical sense. A pain patient who is asked to evaluate his/her perceived pain is highly likely to base this evaluation on previous pain experiences. In sum, the relationship between stimulus intensity, ERP peaks, and pain

Habituation is the process that refers to a decrease in a behavioral response to a repeatedly presented stimulus (Thompson & Spencer, 1966). It could be hypothesized that altered habituation might be an explanation for the chronification of pain. It is thought that chronic pain patients may have a deficit in habituation or even an inability to habituate to painful experiences, resulting in persistent pain. Older studies, using pain rating as an outcome

experience is probably far more complex than previously thought.

**3.2 Habituation and pain-evoked potentials** 

**3.1 Stimulus intensity and subjective pain experience** 

previously.

measure, reported mixed results. One study investigated the habituation difference between CLBP patients and controls, using eight successive trials of the cold pressure test (Brandt & Schmidt, 1987). Healthy controls could be divided into a subgroup that habituated over trials and a subgroup that sensitized. The CLBP group did not habituate or sensitize over time. Additionally, they found a lower pain tolerance in CLBP patients while reporting higher pain ratings. It was hypothesized that CLBP patients had already undergone a learning process in which sensitization had taken place. Arntz and colleagues (1991) also studied habituation in CLBP patients and controls. They did not observe a difference in habituation between the groups, measured by pain intensity ratings, EMG, and heart rate. A third study (Peters et al., 1989) confirmed the results of Brandt & Schmidt (1987) but did not find differences in physiological measures, such as heart rate and skin conductance. More recently, Smith and colleagues (2008) reported differences in habituation of subjective pain ratings between women with fibromyalgia and pain-free controls. They found that women with fibromyalgia habituated at a lower rate to repeated heat stimuli.

In addition, there are some recent studies that have used ERP as a measure to study habituation. They are suggestive of a deficit in habituation in chronic pain patients, although different chronic pain populations were used. Valeriani and colleagues (2003) studied habituation in response to painful CO2 laser stimulation in migraine patients. They found reduced habituation of ERP amplitudes in migraine sufferers compared to pain-free controls. In disconfirmation, another study found that patients with migraine did not show any habituation, whereas healthy controls did (De Tommaso, 2005). Vossen et al. (2010c) studied habituation in a group of chronic low back pain patients compared to pain-free controls, measuring ERP in response to 20 painful stimuli. They found a significant interaction between group and trial number on the P300 component at C4 and T4. This means that chronic low back pain patients appeared to habituate to a lesser degree than pain-free controls. They also examined the influence of state-depression on habituation, using the BDI score. The results revealed a significant three-way interaction between BDI, group, and trialinverse, suggesting that the difference in habituation between groups depends on the level of depression. Only in the presence of depression did CLBP patients show a deficit in habituation. Interestingly, a recent study in fibromyalgia patients also found evidence for reduced habituation of the N200 vertex component, facilitated by the presence of symptoms of depression (De Tommaso, 2011). In conclusion, habituation seems to be different in chronic back pain patients compared to controls but is probably also influenced by factors, such as depression.

#### **3.3 Influence of neuroticism on pain-evoked potentials**

"Personality" can be defined as a dynamic and organized set of characteristics possessed by a person that uniquely influence his or her cognitions, motivations, and behaviors in various situations (Ryckman, 2008). Individuals with different personalities will differ in reaction to a specific situation. Likewise, it is conceivable that persons with diverse personality structures will react differently to a pain stimulus. This theoretical claim is frequently being confirmed in clinical practice. There is a large variety in 'pain behaviors' when patients are confronted with painful medical procedures (injections, stitches, etc.). One of the most important personality factors that are known to influence the experience of pain is neuroticism (Wade et al., 1992). Neuroticism is defined as a tendency to experience negative

The Use of Event-Related Potentials in Chronic Back Pain Patients 123

Heritability for migraine has been estimated at 35% (Stam et al., 2010), 55% for menstrual pain (Treloar et al., 1998), and 33% to 50% for low back pain (Bengtsson & Thorson, 1991 Battié et al., 2007). The main aim in pain genetics, however, is to identify the actual genes and gene polymorphisms that influence the pain pathways. Linkage and association studies have attempted to identify specific genes that affect the peripheral nervous system through the voltage-gated sodium channels on the one hand and genes that affect the central nervous system and modulate sensory-discriminatory and affective-evaluative elements of pain perception that affects the central nervous system on the other (for an extensive overview, see Foulkes & Wood, 2008). Many candidate genes have been proposed, but the effects of these genes are small and even together, if true, explain only a fraction of the heritability involved. A possible explanation for this is the complexity of pain as a phenotype. Measurement of the pain experience plays an important part in this. In human studies, three single-nucleotide polymorphisms (SNPs) have been proposed to impact pain perception: COMT Val158Met (rs4680), BDNF Val66Met (rs6265), and OPRM A118G (rs1799971). COMT Val158Met is a gene polymorphism that alters the activity of the COMT enzyme, which degrades catecholamines, such as dopamine, epinephrine, and norepinephrine (Nackley et al., 2006). It has been demonstrated that Met/Met homozygotes have decreased mu-opioid system activation in response to pain (Zubieta et al., 2001, 2003); however, further replication is required. Brain-derived neurotrophic factor (BDNF) is a neurotrophin that supports the growth, differentiation, and survival of neurons in both the peripheral and the central nervous system. BDNF is released when nociceptors are activated and is involved in the activity-dependent pathogenesis of nociceptive pathways, which may lead to chronification of pain (Merighi et al., 2008; Sen et al., 2008). One piece of genetic variation within the BDNF gene is a valine-to-metionine substitution at codon 66 (Val66Met), resulting in reduced secretion of the BDNF protein and impaired BDNF signaling. The Met carriers are believed to be more sensitive to pain; however, here,

Experimental designs represent a particularly powerful approach to study genetic effects on psychological phenotypes, as they allow for controlled conditions and investigation of

Lötsch and colleagues (2006) studied the influence of the G allele of the OPRM1 A118G polymorphism on ERP pain processing of experimental pain stimuli. This polymorphism replaces adenine with guanine, increasing the receptor affinity of b-endorphin 3-fold, resulting in decreased pain responses (Bond et al., 1998; Filligim et al., 2005). Lötsch and colleagues concluded that ERP amplitudes (N1 component) of carriers of the G allele were, on average, half as high as the amplitude of the non-carriers, suggesting lower pain

In a more recent study, we investigated the influence of the COMT Val158Met, BDNF Val66Met, and BDNF Val66Met polymorphisms on pain using ERPs (Vossen et al., 2010a). The sample of this study consisted of chronic low back pain patients, as well as healthy controls. The results suggest that the COMT Val158Met and the BDNF Val66Met polymorphisms influence the cortical processing of experimental electrical pain stimuli. However, no main gene effects were observed. Rather, genetic effects appeared to be moderated by the concurrent presence of chronic pain complaints. In the presence of chronic pain, the COMT Met allele and the BDNF Met allele augmented cortical pain processing at

replication in large and systematic studies is also required.

underlying mechanisms (van Os et al., 2008).

processing for the G allele carriers.

emotions in stressful situations (Costa & McCrae, 1980). One of the most commonly used questionnaire measuring neuroticism, is the NEO-Big 5 (Costa & McCrae, 1985), which also gives information on six neuroticism facets—namely anxiety, impulsivity, depression, selfconsciousness, irritability, and vulnerability.

There are several mechanisms that explain the hypothesized relationship between neuroticism and pain. In the first explanation, the relationship between neuroticism and pain is thought to arise from over-reporting of pain-related complaints, an exaggerated expression of disturbance, and a more focussed view on bodily states. Persons with high levels of neuroticism tend to be more aware of their bodily states than others and thus report more physical complaints (Groth-Marnat & Fletcher, 2000). Costa and McCrae (1980) suggest that in patients with high levels of neuroticism, physical complaints can be viewed as exaggerations of bodily concerns, linking neuroticism to hypochondria. In yet another explanation, neuroticism can be seen as a vulnerability factor. When a patient is confronted with a stressor, such as low back pain, patients with high neuroticism levels already might perceive pain as threatening at lower thresholds, which consequently may evoke catastrophic thoughts (Goubert et al., 2004). In a study on a large sample (n = 1441) of CLBP patients, Bendebba found a correlation between the severity of perceived pain and psychological distress. A correlation between psychological distress and the duration of the complaint, however, could not be demonstrated (Bendebba, 1997).

Note that the aforementioned studies are based on data derived from questionnaires. ERP can be used as an additional tool to get more insight into the mechanism(s) of pain and neuroticism. Vossen et al. performed a study in 75 healthy subjects in which they studied the influence of neuroticism and two NEO-big 5 facets (depression and anxiety) on the pain-ERP. They found that subjects with relatively high neuroticism scores showed more positive ERP amplitudes. These amplitude effects were observed frontally in a broad latency range, from 250 to 1500 ms, with significant effects between 340-400 ms, 730-860 ms, and 1240-1450 ms, suggesting stronger pain processing. Comparing the effects of the neuroticism facets anxiety and depression, opposite effects were found. Anxiety was associated with a negative effect (enlarging negative amplitudes) early in the ERP (100-200 ms), whereas depression exerted an opposite effect in the same latency range. Another study of 14 healthy participants also found anxiety to be related with a larger N140 component (Warbrick, 2006). In addition, the authors also observed no effect of anxiety in the P300 range. It is known that the N140 increases when attention to a stimulus is heightened (Kida et al., 2004). It is plausible that participants focus their attention more when they are more anxious, thus increasing the amplitude of N140. This would support the idea of a greater focus on bodily states in anxious patients. In conclusion, the number of pain-ERP studies investigating the relationship between personality factors (especially neuroticism) is relatively small. More experimental data are needed to unravel mechanisms involving pain report, personality, and cortical pain processing.

#### **3.4 The influence of gene polymorphisms on pain-evoked potentials**

There is a rising interest in genetic factors in pain research, as they likely explain a substantial portion of the interindividual differences in pain perception and response to pain treatment (Fillingim et al., 2008). Twin studies give the opportunity to determine the proportion of variability in pain response that is accounted for by genes (heritability).

emotions in stressful situations (Costa & McCrae, 1980). One of the most commonly used questionnaire measuring neuroticism, is the NEO-Big 5 (Costa & McCrae, 1985), which also gives information on six neuroticism facets—namely anxiety, impulsivity, depression, self-

There are several mechanisms that explain the hypothesized relationship between neuroticism and pain. In the first explanation, the relationship between neuroticism and pain is thought to arise from over-reporting of pain-related complaints, an exaggerated expression of disturbance, and a more focussed view on bodily states. Persons with high levels of neuroticism tend to be more aware of their bodily states than others and thus report more physical complaints (Groth-Marnat & Fletcher, 2000). Costa and McCrae (1980) suggest that in patients with high levels of neuroticism, physical complaints can be viewed as exaggerations of bodily concerns, linking neuroticism to hypochondria. In yet another explanation, neuroticism can be seen as a vulnerability factor. When a patient is confronted with a stressor, such as low back pain, patients with high neuroticism levels already might perceive pain as threatening at lower thresholds, which consequently may evoke catastrophic thoughts (Goubert et al., 2004). In a study on a large sample (n = 1441) of CLBP patients, Bendebba found a correlation between the severity of perceived pain and psychological distress. A correlation between psychological distress and the duration of the

Note that the aforementioned studies are based on data derived from questionnaires. ERP can be used as an additional tool to get more insight into the mechanism(s) of pain and neuroticism. Vossen et al. performed a study in 75 healthy subjects in which they studied the influence of neuroticism and two NEO-big 5 facets (depression and anxiety) on the pain-ERP. They found that subjects with relatively high neuroticism scores showed more positive ERP amplitudes. These amplitude effects were observed frontally in a broad latency range, from 250 to 1500 ms, with significant effects between 340-400 ms, 730-860 ms, and 1240-1450 ms, suggesting stronger pain processing. Comparing the effects of the neuroticism facets anxiety and depression, opposite effects were found. Anxiety was associated with a negative effect (enlarging negative amplitudes) early in the ERP (100-200 ms), whereas depression exerted an opposite effect in the same latency range. Another study of 14 healthy participants also found anxiety to be related with a larger N140 component (Warbrick, 2006). In addition, the authors also observed no effect of anxiety in the P300 range. It is known that the N140 increases when attention to a stimulus is heightened (Kida et al., 2004). It is plausible that participants focus their attention more when they are more anxious, thus increasing the amplitude of N140. This would support the idea of a greater focus on bodily states in anxious patients. In conclusion, the number of pain-ERP studies investigating the relationship between personality factors (especially neuroticism) is relatively small. More experimental data are needed to unravel mechanisms involving pain report, personality,

consciousness, irritability, and vulnerability.

and cortical pain processing.

complaint, however, could not be demonstrated (Bendebba, 1997).

**3.4 The influence of gene polymorphisms on pain-evoked potentials** 

There is a rising interest in genetic factors in pain research, as they likely explain a substantial portion of the interindividual differences in pain perception and response to pain treatment (Fillingim et al., 2008). Twin studies give the opportunity to determine the proportion of variability in pain response that is accounted for by genes (heritability). Heritability for migraine has been estimated at 35% (Stam et al., 2010), 55% for menstrual pain (Treloar et al., 1998), and 33% to 50% for low back pain (Bengtsson & Thorson, 1991 Battié et al., 2007). The main aim in pain genetics, however, is to identify the actual genes and gene polymorphisms that influence the pain pathways. Linkage and association studies have attempted to identify specific genes that affect the peripheral nervous system through the voltage-gated sodium channels on the one hand and genes that affect the central nervous system and modulate sensory-discriminatory and affective-evaluative elements of pain perception that affects the central nervous system on the other (for an extensive overview, see Foulkes & Wood, 2008). Many candidate genes have been proposed, but the effects of these genes are small and even together, if true, explain only a fraction of the heritability involved. A possible explanation for this is the complexity of pain as a phenotype. Measurement of the pain experience plays an important part in this. In human studies, three single-nucleotide polymorphisms (SNPs) have been proposed to impact pain perception: COMT Val158Met (rs4680), BDNF Val66Met (rs6265), and OPRM A118G (rs1799971). COMT Val158Met is a gene polymorphism that alters the activity of the COMT enzyme, which degrades catecholamines, such as dopamine, epinephrine, and norepinephrine (Nackley et al., 2006). It has been demonstrated that Met/Met homozygotes have decreased mu-opioid system activation in response to pain (Zubieta et al., 2001, 2003); however, further replication is required. Brain-derived neurotrophic factor (BDNF) is a neurotrophin that supports the growth, differentiation, and survival of neurons in both the peripheral and the central nervous system. BDNF is released when nociceptors are activated and is involved in the activity-dependent pathogenesis of nociceptive pathways, which may lead to chronification of pain (Merighi et al., 2008; Sen et al., 2008). One piece of genetic variation within the BDNF gene is a valine-to-metionine substitution at codon 66 (Val66Met), resulting in reduced secretion of the BDNF protein and impaired BDNF signaling. The Met carriers are believed to be more sensitive to pain; however, here, replication in large and systematic studies is also required.

Experimental designs represent a particularly powerful approach to study genetic effects on psychological phenotypes, as they allow for controlled conditions and investigation of underlying mechanisms (van Os et al., 2008).

Lötsch and colleagues (2006) studied the influence of the G allele of the OPRM1 A118G polymorphism on ERP pain processing of experimental pain stimuli. This polymorphism replaces adenine with guanine, increasing the receptor affinity of b-endorphin 3-fold, resulting in decreased pain responses (Bond et al., 1998; Filligim et al., 2005). Lötsch and colleagues concluded that ERP amplitudes (N1 component) of carriers of the G allele were, on average, half as high as the amplitude of the non-carriers, suggesting lower pain processing for the G allele carriers.

In a more recent study, we investigated the influence of the COMT Val158Met, BDNF Val66Met, and BDNF Val66Met polymorphisms on pain using ERPs (Vossen et al., 2010a). The sample of this study consisted of chronic low back pain patients, as well as healthy controls. The results suggest that the COMT Val158Met and the BDNF Val66Met polymorphisms influence the cortical processing of experimental electrical pain stimuli. However, no main gene effects were observed. Rather, genetic effects appeared to be moderated by the concurrent presence of chronic pain complaints. In the presence of chronic pain, the COMT Met allele and the BDNF Met allele augmented cortical pain processing at

The Use of Event-Related Potentials in Chronic Back Pain Patients 125

consecutive weeks. Surprisingly, the ERP variables related more strongly to the clinical pain ratings than the accompanying subjective ratings of the experimental pain stimuli. Although care must be taken in the interpretation of these results, the findings suggest that it might be possible to make inferences on clinical pain, based on experimentally derived pain-ERPs. More studies are needed to confirm these results and to investigate the usefulness of

In the last 2 decades, the methods of analyzing ERPs have not been changed essentially. In the first paragraph, we will describe the most commonly used method. In the second paragraph, we will discuss several issues concerning the methodology. Additionally, we

In an experimental ERP paradigm, stimuli are repeated to allow averaging of the epochs and to compare different experimentally induced conditions. Although many variants are possible, the most common procedure of ERP analysis is as follows (Luck, 2005; Mouraux & Iannetti, 2008) : The first step is to filter the raw EEG data. The second step is the creation of segments or epochs, based on markers of the stimuli in the EEG. The duration of these epochs varies but is usually between 500 and 1500 ms. The third step concerns identification of invalid epochs. Epochs are qualified as valid or not, depending on whether an epoch is likely to be confounded by an artifact: electrical activity that does not arise from the brain for example, an eyelid movement, tension of the muscles in the head and neck, or electrical activity from the heart. Basically, there are two procedures for dealing with invalid epochs. The first method is a rejection of invalid epochs in the computation of the averaged ERP. This simply reduces the maximum number of analyzable segments, and as a result, information is lost. The second option is a correction for confounding effects by commonly accepted statistical algorithms, such as the so-called Gratton and Coles ocular correction (Gratton, 1983). To date, it is not clear which of these two methods is preferable. After the averaging of all epochs per individual (step 4), a grand average of ERP segments across subjects (per experimental condition) is calculated (step 5). The next action is to carefully identify peaks with their corresponding latency windows: a time range surrounding a specific peak. The seventh step is to apply these 'peak latency windows' at the withinsubject epoch level: within the defined latency window, the maximum (or minimum) amplitude is determined. These maximum amplitudes form the input for the computation of the peak average for each individual. The final action is to use these maximum or minimum amplitudes as a dependent variable in statistical analyses, such as ANOVA

Although this procedure of ERP analysis is plausible, functional, and generally accepted, there are some critical issues that need to be considered, particularly given recent developments in statistics that may provide superior analytical approaches. First, each timelocked EEG segment consists of the aimed signal and a noise element (all background

predicting long-term complaints in patients with acute or chronic back pain.

will introduce an alternative method and present preliminary results.

**4. Analyzing event-related potentials** 

**4.1 Common methods in analyzing pain-ERPs** 

(Hoormann et al., 1998).

**4.2 Methodological considerations** 

the N2 and P1 components, respectively, whilst reducing pain processing in pain-free controls. The findings of Lötsch and colleagues (2006) concerning the OPRM1 A118G polymorphism could not be replicated in our study. The influence of chronic pain complaints on gene effects may indicate a gene-environment interaction and may even implicate epigenetic modification. It is clear that genetic findings remain preliminary, and well-conducted systematic studies with larger samples sizes are required.

Up to now, limited attention has gone out to gene-environment interplay in pain research, especially with event-related potentials as pain measure. In future studies investigating gene-environment interplay, the complexity of the phenotype and the overall small direct effect of genes (Manolio et al., 2009) should be considered. Longitudinal designs using event-related potentials can contribute to the study of genetic influences in causal pathways of the chronification of pain.

#### **3.5 The predictive relationship of pain-ERPs to clinical experience of pain**

Since chronic low back pain is a very common problem and accompanied by high costs in health care, it is important to be able to predict the likelihood of developing chronic disabling back pain. In 2010, Chou & Chelleke performed a systematic review of 20 studies to investigate the usefulness of individual risk factors for chronification in low back pain. Identified risk factors, although individually relatively weak, were maladaptive pain coping behaviors, nonorganic signs, functional impairment, a poor general health status, and presence of psychiatric comorbidities. They also reviewed risk-predicting instruments, which are usually based on self-reported questionnaires. To date, no instrument has been used routinely and no recommendations exist, since evidence is insufficient (Chou & Chelleke, 2010). Could the pain-ERP serve as a predictor for chronic low back pain? The experimentally induced pain-ERP has been demonstrated to be a relatively objective measure of experimental pain compared to subjective pain ratings (Becker et al., 2000; Bromm, 1984; Stowell, 1977). An important issue, however, concerns the relevance and translation of the experimentally induced pain-ERP to pain in daily life. Stated in another way, can the pain-ERP serve as a predictor for clinical pain? There are two fundamental problems, which are related to the meaning of experimentally induced pain and its generalizability to pain in daily life. First, the characteristics of experimentally induced pain stimuli are typically not comparable with those of clinical pain (e.g., the intensity and duration). Second, in an experimental environment, the subject has at least partial control of the experimentally induced pain (escape is possible by stopping the participation), a controllability that cannot be exerted in a clinical setting. Consequently, a straightforward translation of experimentally induced pain to clinical pain is simply not possible. Nevertheless, event-related potentials have already been used to predict depression (Kemp et al., 2006), awakening from a coma (Daltrozzo et al., 2006), and in the discrimination of Alzheimer's disease from controls (Benvenuto et al., 2002). The prediction of pain, using ERPs, has not been studied intensively. To our knowledge, only one study investigated the prediction of chronic low back pain complaints (Vossen et al., 2010b). Even-related potentials in response to experimental pain were measured in 75 CLBP patients. The ERP mean amplitudes of the peaks (N1, P1, N2, P3) served as predictors for the mean pain ratings, registered during a 2-week period after the experiment. The N2 component of Cz and C4 appeared to be significantly related to the daily pain ratings, collected over 2 consecutive weeks. Surprisingly, the ERP variables related more strongly to the clinical pain ratings than the accompanying subjective ratings of the experimental pain stimuli. Although care must be taken in the interpretation of these results, the findings suggest that it might be possible to make inferences on clinical pain, based on experimentally derived pain-ERPs. More studies are needed to confirm these results and to investigate the usefulness of predicting long-term complaints in patients with acute or chronic back pain.

#### **4. Analyzing event-related potentials**

124 Low Back Pain

the N2 and P1 components, respectively, whilst reducing pain processing in pain-free controls. The findings of Lötsch and colleagues (2006) concerning the OPRM1 A118G polymorphism could not be replicated in our study. The influence of chronic pain complaints on gene effects may indicate a gene-environment interaction and may even implicate epigenetic modification. It is clear that genetic findings remain preliminary, and

Up to now, limited attention has gone out to gene-environment interplay in pain research, especially with event-related potentials as pain measure. In future studies investigating gene-environment interplay, the complexity of the phenotype and the overall small direct effect of genes (Manolio et al., 2009) should be considered. Longitudinal designs using event-related potentials can contribute to the study of genetic influences in causal pathways

Since chronic low back pain is a very common problem and accompanied by high costs in health care, it is important to be able to predict the likelihood of developing chronic disabling back pain. In 2010, Chou & Chelleke performed a systematic review of 20 studies to investigate the usefulness of individual risk factors for chronification in low back pain. Identified risk factors, although individually relatively weak, were maladaptive pain coping behaviors, nonorganic signs, functional impairment, a poor general health status, and presence of psychiatric comorbidities. They also reviewed risk-predicting instruments, which are usually based on self-reported questionnaires. To date, no instrument has been used routinely and no recommendations exist, since evidence is insufficient (Chou & Chelleke, 2010). Could the pain-ERP serve as a predictor for chronic low back pain? The experimentally induced pain-ERP has been demonstrated to be a relatively objective measure of experimental pain compared to subjective pain ratings (Becker et al., 2000; Bromm, 1984; Stowell, 1977). An important issue, however, concerns the relevance and translation of the experimentally induced pain-ERP to pain in daily life. Stated in another way, can the pain-ERP serve as a predictor for clinical pain? There are two fundamental problems, which are related to the meaning of experimentally induced pain and its generalizability to pain in daily life. First, the characteristics of experimentally induced pain stimuli are typically not comparable with those of clinical pain (e.g., the intensity and duration). Second, in an experimental environment, the subject has at least partial control of the experimentally induced pain (escape is possible by stopping the participation), a controllability that cannot be exerted in a clinical setting. Consequently, a straightforward translation of experimentally induced pain to clinical pain is simply not possible. Nevertheless, event-related potentials have already been used to predict depression (Kemp et al., 2006), awakening from a coma (Daltrozzo et al., 2006), and in the discrimination of Alzheimer's disease from controls (Benvenuto et al., 2002). The prediction of pain, using ERPs, has not been studied intensively. To our knowledge, only one study investigated the prediction of chronic low back pain complaints (Vossen et al., 2010b). Even-related potentials in response to experimental pain were measured in 75 CLBP patients. The ERP mean amplitudes of the peaks (N1, P1, N2, P3) served as predictors for the mean pain ratings, registered during a 2-week period after the experiment. The N2 component of Cz and C4 appeared to be significantly related to the daily pain ratings, collected over 2

well-conducted systematic studies with larger samples sizes are required.

**3.5 The predictive relationship of pain-ERPs to clinical experience of pain** 

of the chronification of pain.

In the last 2 decades, the methods of analyzing ERPs have not been changed essentially. In the first paragraph, we will describe the most commonly used method. In the second paragraph, we will discuss several issues concerning the methodology. Additionally, we will introduce an alternative method and present preliminary results.

#### **4.1 Common methods in analyzing pain-ERPs**

In an experimental ERP paradigm, stimuli are repeated to allow averaging of the epochs and to compare different experimentally induced conditions. Although many variants are possible, the most common procedure of ERP analysis is as follows (Luck, 2005; Mouraux & Iannetti, 2008) : The first step is to filter the raw EEG data. The second step is the creation of segments or epochs, based on markers of the stimuli in the EEG. The duration of these epochs varies but is usually between 500 and 1500 ms. The third step concerns identification of invalid epochs. Epochs are qualified as valid or not, depending on whether an epoch is likely to be confounded by an artifact: electrical activity that does not arise from the brain for example, an eyelid movement, tension of the muscles in the head and neck, or electrical activity from the heart. Basically, there are two procedures for dealing with invalid epochs. The first method is a rejection of invalid epochs in the computation of the averaged ERP. This simply reduces the maximum number of analyzable segments, and as a result, information is lost. The second option is a correction for confounding effects by commonly accepted statistical algorithms, such as the so-called Gratton and Coles ocular correction (Gratton, 1983). To date, it is not clear which of these two methods is preferable. After the averaging of all epochs per individual (step 4), a grand average of ERP segments across subjects (per experimental condition) is calculated (step 5). The next action is to carefully identify peaks with their corresponding latency windows: a time range surrounding a specific peak. The seventh step is to apply these 'peak latency windows' at the withinsubject epoch level: within the defined latency window, the maximum (or minimum) amplitude is determined. These maximum amplitudes form the input for the computation of the peak average for each individual. The final action is to use these maximum or minimum amplitudes as a dependent variable in statistical analyses, such as ANOVA (Hoormann et al., 1998).

#### **4.2 Methodological considerations**

Although this procedure of ERP analysis is plausible, functional, and generally accepted, there are some critical issues that need to be considered, particularly given recent developments in statistics that may provide superior analytical approaches. First, each timelocked EEG segment consists of the aimed signal and a noise element (all background

The Use of Event-Related Potentials in Chronic Back Pain Patients 127

already starts at approximately 200 ms and lasts at least until 500 ms. Also, the intensity effect between P1 and N2 can not be ignored. The second graph illustrates the effects on habituation. The three ERPs represent three blocks of trials delivered in the experiment. Again, habituation is not restricted visually to the peaks. Also, habituation seems to reduce the amplitude. In the third graph, two grand averages are shown of ERPs on Cz: one from a pain-free control group (n = 76) and the other from a group of chronic low back patients (n = 75). There seem to be small amplitude group effects on the P1 and N2 but not on the P2. In addition, there seem to be non-peak-related group effects. Care must be taken in the interpretation of differences observed in these grand averages, since they represent a reduced, oversimplified representation of the pain experience. In the intensity ERPs, the

Based on these observations, we performed a number of (unpublished) pilot analyses on ERP datasets of previous studies to determine a pragmatic width of AUC segments (ERFIAs). This led to our choice of segments of 20 ms. In our view, this seems to be a reasonable compromise between specific AUC segments that are too large on the one hand

We decided to reanalyze part of the data pertaining to the PhD thesis, defended by H. Vossen. We focused the preliminary analysis on three electrodes, namely C3, C4, and Cz, because these locations represent the sensomotoric cortex and are of anatomical importance in pain processing (Kupers & Kehlet, 2006). Also, we restricted the range to 0-500 ms poststimulus. The reanalysis took place in an explorative, hypothesis-generating fashion. Basically, we were interested in to what degree the proposed ERFIA method would yield significant relationships between stimulus intensity and habituation and to what degree these findings would correspond to known results, based on peak analyses. In addition, there was one special point of interest: Do the ERPs of chronic pain patients differ from

and segments that are too small, resulting in multiple testing problems on the other.

information on habituation is averaged out and vice versa.

pain-free controls, analyzed with fixed-interval AUCs?

Fig. 3. Grand ERPs of stimulus intensity on Cz.

ongoing EEG activity). Averaging of the trials will separate the signal from the noise, because the signal element is thought to be constant in every trial, while the noise element is considered to be random. However, one can dispute the fact that a signal is constant over trials in pain experiments, since processes, such as habituation, play an important role (Woestenburg et al., 1983; Vossen et al., 2006). In addition, within-subject variance (trial-totrial variance) is lost by averaging, which may contain clinically important information on cortical processes. Second, it is known that in consecutive trials, the latency of maximum peak values is likely to differ. Although it is possible to take the variability of latency into account in the analysis (as a covariate), this solution is not ideal, since the trial-to-trial latency information is lost. A third unsolved problem is how to deal with peak values located on the borders of the latency window. A final critical point regards the fact that peaks contain information on many processes: it is generally known that P300 is sensitive for attention, evaluation, stimulus intensity, and many other stimulus-related and personrelated factors (Zaslansky et al., 1996). Multilevel random regression analysis, as already discussed in paragraph 3.2, tackles the problems associated with averaging and habituation. Nonetheless, the methodological problems concerning peak definition and peak measurement can not be solved with multilevel analysis.

Without a doubt, averaged maximized peak values carry important information. However, theoretically spoken, each (!) latency point contains meaningful information. To be able to analyze amplitude information that is not related to peaks, area under the curve (AUC) can be computed for specific latency ranges. Usually, AUC is applied to quantify peaks as well as to calculate averaged group differences located on the flanks/limbs of a peak (Luck, 2005). AUC is not often applied in pain-ERPs, since it has been postulated that more noise is introduced when averaging trials (Picton, 2000). However, when using AUCs of single-trial data, the problem of introducing noise is substantially reduced.

#### **5. Introducing an alternative method**

In this section, we will discuss an alternative method for analyzing ERP data. We will present preliminary results using this method in a previously used dataset of CLBP patients and pain-free controls.

#### **5.1 Fixed-interval AUC segment analysis**

From a statistical point of view, the main goal of ERP analysis is to explain variance in the pain-ERP as much as possible, using a series of predictors. It seems reasonable to focus not only on the explanation of maximum peak amplitudes but also on effects in other latencies. This assertion is supported by the fact that several above-cited publications (e.g., Kanda et al., 2002; Vossen et al., 2006) report stimulus- and person-related effects in non-peak latencies. We felt that the concept of AUC is valuable but should be applied to small fixed intervals, independent of peaks. This implicates a partitioning of the whole epoch in small event-related fixed interval areas (ERFIAs). To illustrate this line of reasoning, three averaged pain-ERPs are presented. In the first picture, three ERPs are depicted, each representing another level of stimulus intensity. As can be observed, there are intensity effects on P1 and N2 and a large effect on P2: the larger the intensity, the larger the peak amplitude. However, the intensity effects are not limited to these peaks. The effect on the P2

ongoing EEG activity). Averaging of the trials will separate the signal from the noise, because the signal element is thought to be constant in every trial, while the noise element is considered to be random. However, one can dispute the fact that a signal is constant over trials in pain experiments, since processes, such as habituation, play an important role (Woestenburg et al., 1983; Vossen et al., 2006). In addition, within-subject variance (trial-totrial variance) is lost by averaging, which may contain clinically important information on cortical processes. Second, it is known that in consecutive trials, the latency of maximum peak values is likely to differ. Although it is possible to take the variability of latency into account in the analysis (as a covariate), this solution is not ideal, since the trial-to-trial latency information is lost. A third unsolved problem is how to deal with peak values located on the borders of the latency window. A final critical point regards the fact that peaks contain information on many processes: it is generally known that P300 is sensitive for attention, evaluation, stimulus intensity, and many other stimulus-related and personrelated factors (Zaslansky et al., 1996). Multilevel random regression analysis, as already discussed in paragraph 3.2, tackles the problems associated with averaging and habituation. Nonetheless, the methodological problems concerning peak definition and peak

Without a doubt, averaged maximized peak values carry important information. However, theoretically spoken, each (!) latency point contains meaningful information. To be able to analyze amplitude information that is not related to peaks, area under the curve (AUC) can be computed for specific latency ranges. Usually, AUC is applied to quantify peaks as well as to calculate averaged group differences located on the flanks/limbs of a peak (Luck, 2005). AUC is not often applied in pain-ERPs, since it has been postulated that more noise is introduced when averaging trials (Picton, 2000). However, when using AUCs of single-trial

In this section, we will discuss an alternative method for analyzing ERP data. We will present preliminary results using this method in a previously used dataset of CLBP patients

From a statistical point of view, the main goal of ERP analysis is to explain variance in the pain-ERP as much as possible, using a series of predictors. It seems reasonable to focus not only on the explanation of maximum peak amplitudes but also on effects in other latencies. This assertion is supported by the fact that several above-cited publications (e.g., Kanda et al., 2002; Vossen et al., 2006) report stimulus- and person-related effects in non-peak latencies. We felt that the concept of AUC is valuable but should be applied to small fixed intervals, independent of peaks. This implicates a partitioning of the whole epoch in small event-related fixed interval areas (ERFIAs). To illustrate this line of reasoning, three averaged pain-ERPs are presented. In the first picture, three ERPs are depicted, each representing another level of stimulus intensity. As can be observed, there are intensity effects on P1 and N2 and a large effect on P2: the larger the intensity, the larger the peak amplitude. However, the intensity effects are not limited to these peaks. The effect on the P2

measurement can not be solved with multilevel analysis.

data, the problem of introducing noise is substantially reduced.

**5. Introducing an alternative method** 

**5.1 Fixed-interval AUC segment analysis** 

and pain-free controls.

already starts at approximately 200 ms and lasts at least until 500 ms. Also, the intensity effect between P1 and N2 can not be ignored. The second graph illustrates the effects on habituation. The three ERPs represent three blocks of trials delivered in the experiment. Again, habituation is not restricted visually to the peaks. Also, habituation seems to reduce the amplitude. In the third graph, two grand averages are shown of ERPs on Cz: one from a pain-free control group (n = 76) and the other from a group of chronic low back patients (n = 75). There seem to be small amplitude group effects on the P1 and N2 but not on the P2. In addition, there seem to be non-peak-related group effects. Care must be taken in the interpretation of differences observed in these grand averages, since they represent a reduced, oversimplified representation of the pain experience. In the intensity ERPs, the information on habituation is averaged out and vice versa.

Based on these observations, we performed a number of (unpublished) pilot analyses on ERP datasets of previous studies to determine a pragmatic width of AUC segments (ERFIAs). This led to our choice of segments of 20 ms. In our view, this seems to be a reasonable compromise between specific AUC segments that are too large on the one hand and segments that are too small, resulting in multiple testing problems on the other.

We decided to reanalyze part of the data pertaining to the PhD thesis, defended by H. Vossen. We focused the preliminary analysis on three electrodes, namely C3, C4, and Cz, because these locations represent the sensomotoric cortex and are of anatomical importance in pain processing (Kupers & Kehlet, 2006). Also, we restricted the range to 0-500 ms poststimulus. The reanalysis took place in an explorative, hypothesis-generating fashion. Basically, we were interested in to what degree the proposed ERFIA method would yield significant relationships between stimulus intensity and habituation and to what degree these findings would correspond to known results, based on peak analyses. In addition, there was one special point of interest: Do the ERPs of chronic pain patients differ from pain-free controls, analyzed with fixed-interval AUCs?

Fig. 3. Grand ERPs of stimulus intensity on Cz.

The Use of Event-Related Potentials in Chronic Back Pain Patients 129

five used intensities were -50% and -25% below the pain threshold, the pain threshold itself (0%), and 25% and 50% above the pain threshold. After each stimulus, subjects were asked to rate the intensity on a numeric rating scale (NRS) ranging from 0 to 100. During the entire experiment, EEG was recorded with a 1000-Hz sampling rate. The ERP epochs were selected from the continuous EEG and segmented at 200 ms prior to the stimulus to 500 ms poststimulus. For each stimulus, we calculated 20-ms ERFIAs in the range of 0 to 500 ms. ERFIA segments with EOG activity exceeding +25 mA or -25 mA were excluded from the analysis. The calculated ERFIAs were used as dependent variables in a multilevel random regression model (see equations 1 and 2). This resulted in 25 separate multilevel regression analyses

Yti = β0 + β1\*intensitylinear + β2\*triallinear + β3\*trialquadratic + β4\*trialinverse + β5\*group + β6\*age + β7\*gender + β8\*sensation threshold + β9\*pain threshold + β10\*intensitylinear of previous trial + eti + u1\*\*intensitylinear + u2 \*triallinear + u3\* trialinverse + u4\* trialquadratic

Yti = β0 + β1\*intensitylinear + β2\*triallinear + β3\*trialquadratic + β4\*trialinverse + β5\*group + β6\*age + β7\*gender + β8\*sensation threshold + β9\*pain threshold + β10\*intensitylinear of previous trial + β11\*group\*intensitylinear + β12\*group\*triallinear + β13\*group\*trialquadratic + + β14\*group\*trialinverse+ β15\*group\*intensitylinear of previous trial + β16\*group\*pain threshold + β17\*group\*sensory threshold + eti + u1\*\*intensitylinear + u2 \*triallinear + u3\* trialinverse + u4\* trialquadratic

First, some general group characteristics are presented in Table 1. The CLBP patients report much more pain and pain interference. In addition, as might be expected, their mood is

Age 34.68 42.11 3.15 0.002 Gender male 26 34 2.26 0.09

Pain magnitude (SF-36) 1.65 3.51 13.73 0.000 Pain interference (SF-36) 1.18 2.23 9.84 0.000 Depression (BDI) 3.35 7.09 5.8 0.000

Because of the preliminary aspect of the analyses, a full description of all results is beyond the scope of this chapter. Therefore, the focus will be on the robust and salient results of the

CLBP patients (N = 75)

(1)

(2)

*T-*value/χ<sup>2</sup> *p*-value

per electrode. All analyses were performed with SPSS 18.0.

Mulilevel regression model with three group-interaction effects:

negatively affected, which is expressed in a higher depression score.

(N = 76)

Gender female 50 41

Table 1. Characteristics of the two experimental groups.

Pain-free control

Mulilevel regression model with main effects:

**5.3 Preliminary results** 

analyses.

Fig. 4. Grand ERPs of the three consecutive blocks of stimuli on Cz.

Fig. 5. Grand ERPs of CLBP patients and a pain-free control group on Cz.

#### **5.2 Study design**

The dataset we are using is based on previously collected raw EEG data. For a detailed description of the protocol, we refer to Vossen et al., 2010a & 2011. Here, a summary of the design is given. Seventy-six pain-free subjects and 75 patients with chronic low back pain participated in the study. All CLBP subjects suffered from low back pain for at least 6 months and were recruited from the general population. All subjects underwent a rating paradigm of 150 semi-randomly presented electrical stimuli. The used stimuli, administered intracutaneously on the top of the left middle finger, consisted of electrical pulses, each with a duration of 10 ms, and an inter-stimulus interval (ISI) ranging from 9 to 11 seconds. Before starting the experiment, the sensory and pain threshold were determined. In the experiment, five different intensities, based on the participant's pain threshold, were administered. The five used intensities were -50% and -25% below the pain threshold, the pain threshold itself (0%), and 25% and 50% above the pain threshold. After each stimulus, subjects were asked to rate the intensity on a numeric rating scale (NRS) ranging from 0 to 100. During the entire experiment, EEG was recorded with a 1000-Hz sampling rate. The ERP epochs were selected from the continuous EEG and segmented at 200 ms prior to the stimulus to 500 ms poststimulus. For each stimulus, we calculated 20-ms ERFIAs in the range of 0 to 500 ms. ERFIA segments with EOG activity exceeding +25 mA or -25 mA were excluded from the analysis. The calculated ERFIAs were used as dependent variables in a multilevel random regression model (see equations 1 and 2). This resulted in 25 separate multilevel regression analyses per electrode. All analyses were performed with SPSS 18.0.

Mulilevel regression model with main effects:

Yti = β0 + β1\*intensitylinear + β2\*triallinear + β3\*trialquadratic + β4\*trialinverse + β5\*group + β6\*age + β7\*gender + β8\*sensation threshold + β9\*pain threshold + β10\*intensitylinear of previous trial + eti + u1\*\*intensitylinear + u2 \*triallinear + u3\* trialinverse + u4\* trialquadratic (1)

Mulilevel regression model with three group-interaction effects:

Yti = β0 + β1\*intensitylinear + β2\*triallinear + β3\*trialquadratic + β4\*trialinverse + β5\*group + β6\*age + β7\*gender + β8\*sensation threshold + β9\*pain threshold + β10\*intensitylinear of previous trial + β11\*group\*intensitylinear + β12\*group\*triallinear + β13\*group\*trialquadratic + + β14\*group\*trialinverse+ β15\*group\*intensitylinear of previous trial + β16\*group\*pain threshold + β17\*group\*sensory threshold + eti + u1\*\*intensitylinear + u2 \*triallinear + u3\* trialinverse + u4\* trialquadratic (2)

#### **5.3 Preliminary results**

128 Low Back Pain

Fig. 4. Grand ERPs of the three consecutive blocks of stimuli on Cz.

Fig. 5. Grand ERPs of CLBP patients and a pain-free control group on Cz.

The dataset we are using is based on previously collected raw EEG data. For a detailed description of the protocol, we refer to Vossen et al., 2010a & 2011. Here, a summary of the design is given. Seventy-six pain-free subjects and 75 patients with chronic low back pain participated in the study. All CLBP subjects suffered from low back pain for at least 6 months and were recruited from the general population. All subjects underwent a rating paradigm of 150 semi-randomly presented electrical stimuli. The used stimuli, administered intracutaneously on the top of the left middle finger, consisted of electrical pulses, each with a duration of 10 ms, and an inter-stimulus interval (ISI) ranging from 9 to 11 seconds. Before starting the experiment, the sensory and pain threshold were determined. In the experiment, five different intensities, based on the participant's pain threshold, were administered. The

**5.2 Study design** 

First, some general group characteristics are presented in Table 1. The CLBP patients report much more pain and pain interference. In addition, as might be expected, their mood is negatively affected, which is expressed in a higher depression score.


Table 1. Characteristics of the two experimental groups.

Because of the preliminary aspect of the analyses, a full description of all results is beyond the scope of this chapter. Therefore, the focus will be on the robust and salient results of the analyses.

The Use of Event-Related Potentials in Chronic Back Pain Patients 131

Fig. 6-9. T-values per 20-ms AUC of four separate independent variables.

On the vertical axis, the T-value of the variable is depicted, and the horizontal axis represents latency (i.e., the 25 consecutive 20-ms ERFIAs). The variable intensity, habituation (linear), and previous trial intensity show profound and long-lasting, significant effects, as shown in the figure. Note a significant negative effect of stimulus intensity on all three electrodes from 60 to 120 ms and a very strong positive effect from 160 to 400 ms. Remarkably, two positive intensity processes in the latency range between 100 and 400 ms are apparent (from 140-200 ms and from 200-400 ms). In addition, an asymmetry can be observed between C4 and C3/Cz in the 140-to-200-ms range, where C4 demonstrates no

Fig. 8.

Fig. 9.

We present the results of four independent variables, applied in the first multilevel model (see equation 1): intensity, the intensity of the previous trial, habituation (analyzed with a linear contrast), and group (CLBP patients versus pain-free controls). The results for the 20 ms periods between 0 and 500 ms are shown in Figures 6-9.

Fig. 6.

130 Low Back Pain

We present the results of four independent variables, applied in the first multilevel model (see equation 1): intensity, the intensity of the previous trial, habituation (analyzed with a linear contrast), and group (CLBP patients versus pain-free controls). The results for the 20-

ms periods between 0 and 500 ms are shown in Figures 6-9.

Fig. 6.

Fig. 7.

#### Fig. 9.

Fig. 6-9. T-values per 20-ms AUC of four separate independent variables.

On the vertical axis, the T-value of the variable is depicted, and the horizontal axis represents latency (i.e., the 25 consecutive 20-ms ERFIAs). The variable intensity, habituation (linear), and previous trial intensity show profound and long-lasting, significant effects, as shown in the figure. Note a significant negative effect of stimulus intensity on all three electrodes from 60 to 120 ms and a very strong positive effect from 160 to 400 ms. Remarkably, two positive intensity processes in the latency range between 100 and 400 ms are apparent (from 140-200 ms and from 200-400 ms). In addition, an asymmetry can be observed between C4 and C3/Cz in the 140-to-200-ms range, where C4 demonstrates no

Fig. 11.

The Use of Event-Related Potentials in Chronic Back Pain Patients 133

In paragraph 4.2, several critical points were discussed in relation to ERP peak measures, followed by the proposal of an alternative approach based on AUC, analyzed with multilevel random regression techniques. A number of explorative analyses were performed. We are aware of the fact that the results are merely explorative, since we only analyzed three cranial locations and restricted the analyses to a 500-ms post-stimulus time range. However, given these limitations, we think the analyses show promising results and

As a first step, we investigated whether the 'new' method would yield comparable results, with respect to already established relationships between peak-ERP, stimulus intensity, and habituation. Reviewing our results, the answer seems to be affirmative. Consistent results were found for all three central electrodes. A large number of the 20-ms ERFIA segments were significantly related to stimulus intensity and habituation. When examining the areas in which we would expect significant results for the intensity and habituation variables *a priori*, the alternative method produced results comparable to other studies (e.g., Bromm & Meier, 1984; Stowell, 1977). For example, the main effect of the variable intensity was very significant in the N2 range and the P3 range. A similar observation could be made for linear

In addition to these basic 'validating' analyses, we were also interested in whether ERP-pain processing of CLBP patients differs from pain-free controls. No clear main group effect could be observed. However, the results strongly suggest that the effects on intensity and linear and quadratic habituation depend on being a CLBP patient or not. An interesting observation was that the group\*intensity interaction took place at an earlier latency range compared to the group\*habituation interaction in the ERP. The group\*intensity interaction effect is situated in the latency range of the P3 and probably can be replicated using peak amplitudes. The group\*habituation effect, however, is situated after the P3 and, as a

Fig. 10,11. T-values per 20-ms ERFIAs of two interaction effects.

**5.4 Discussion of the preliminary findings** 

habituation in the N2 range (De Tommaso, 2011).

illustrate proof of concept.

clear significance. In contrast to the results presented by Vossen and colleagues (2011), where no main effects of the previous trial intensity variable were found in peak amplitude analyses, the ERFIAs show a large and consistent negative effect from 320 to 500 ms at all three electrodes. There are some small, significant, positive effects in 180-to-260-ms latency. With respect to linear habituation, large and long-lasting significant t-values can also be identified. The linear habituation emerges from the 100-140-ms range as a significant positive effect and becomes significantly negative in the range from 200-380 ms. Although less pronounced, the linear habituation t-curve appears to be opposite compared to the intensity t-curve; whereas intensity has an amplitude-inflating effect in the range from 140 to 400 ms, linear habituation has the opposite effect. Although not displayed, significant effects were observed for the inverse variables habituation (1/trial) and quadratic habituation. Inverse habituation had a clear, significant (T-values between -2 and -4) amplitude-reducing effect during a latency period of 360-500 ms, and quadratic habituation showed strong, significant amplitude-inflating effects (T-values up to 4) in the range of 200- 300 ms. No convincing main effect of group, independent of the effect of all other variables in the model, could be demonstrated. The only area of interest appears to be located on C4 and is situated between 140 and 200 ms, but taking the number of tests into account (3x25=75), this effect is questionable.

Finally, we investigated whether there were significant interaction effects with the group variable (see equation 2). A priori (see Vossen et al., 2011), we expected a group\*habituation interaction showing CLBP patients to have a reduced habituation. We were also interested in whether the intensity effect was modified by group. In order to limit the number of figures, we present the results on the group by intensity and group by linear habituation interactions (note that group was coded "1" for CLBP patients and "0" for pain-free controls). As can be seen from Figures 10 and 11, the group effect may depend on stimulus intensity (especially in the 200-300-ms range) as well as linear habituation (320-440 ms, especially on Cz). There were also clear significant effects (T-values between 2 and 3 between 320 and 440 ms) for the group by quadratic habituation (no graphs included).

Fig. 10.

#### Fig. 11.

132 Low Back Pain

clear significance. In contrast to the results presented by Vossen and colleagues (2011), where no main effects of the previous trial intensity variable were found in peak amplitude analyses, the ERFIAs show a large and consistent negative effect from 320 to 500 ms at all three electrodes. There are some small, significant, positive effects in 180-to-260-ms latency. With respect to linear habituation, large and long-lasting significant t-values can also be identified. The linear habituation emerges from the 100-140-ms range as a significant positive effect and becomes significantly negative in the range from 200-380 ms. Although less pronounced, the linear habituation t-curve appears to be opposite compared to the intensity t-curve; whereas intensity has an amplitude-inflating effect in the range from 140 to 400 ms, linear habituation has the opposite effect. Although not displayed, significant effects were observed for the inverse variables habituation (1/trial) and quadratic habituation. Inverse habituation had a clear, significant (T-values between -2 and -4) amplitude-reducing effect during a latency period of 360-500 ms, and quadratic habituation showed strong, significant amplitude-inflating effects (T-values up to 4) in the range of 200- 300 ms. No convincing main effect of group, independent of the effect of all other variables in the model, could be demonstrated. The only area of interest appears to be located on C4 and is situated between 140 and 200 ms, but taking the number of tests into account

Finally, we investigated whether there were significant interaction effects with the group variable (see equation 2). A priori (see Vossen et al., 2011), we expected a group\*habituation interaction showing CLBP patients to have a reduced habituation. We were also interested in whether the intensity effect was modified by group. In order to limit the number of figures, we present the results on the group by intensity and group by linear habituation interactions (note that group was coded "1" for CLBP patients and "0" for pain-free controls). As can be seen from Figures 10 and 11, the group effect may depend on stimulus intensity (especially in the 200-300-ms range) as well as linear habituation (320-440 ms, especially on Cz). There were also clear significant effects (T-values between 2 and 3 between 320 and 440 ms) for the group by quadratic habituation (no graphs included).

(3x25=75), this effect is questionable.

Fig. 10.

#### **5.4 Discussion of the preliminary findings**

In paragraph 4.2, several critical points were discussed in relation to ERP peak measures, followed by the proposal of an alternative approach based on AUC, analyzed with multilevel random regression techniques. A number of explorative analyses were performed. We are aware of the fact that the results are merely explorative, since we only analyzed three cranial locations and restricted the analyses to a 500-ms post-stimulus time range. However, given these limitations, we think the analyses show promising results and illustrate proof of concept.

As a first step, we investigated whether the 'new' method would yield comparable results, with respect to already established relationships between peak-ERP, stimulus intensity, and habituation. Reviewing our results, the answer seems to be affirmative. Consistent results were found for all three central electrodes. A large number of the 20-ms ERFIA segments were significantly related to stimulus intensity and habituation. When examining the areas in which we would expect significant results for the intensity and habituation variables *a priori*, the alternative method produced results comparable to other studies (e.g., Bromm & Meier, 1984; Stowell, 1977). For example, the main effect of the variable intensity was very significant in the N2 range and the P3 range. A similar observation could be made for linear habituation in the N2 range (De Tommaso, 2011).

In addition to these basic 'validating' analyses, we were also interested in whether ERP-pain processing of CLBP patients differs from pain-free controls. No clear main group effect could be observed. However, the results strongly suggest that the effects on intensity and linear and quadratic habituation depend on being a CLBP patient or not. An interesting observation was that the group\*intensity interaction took place at an earlier latency range compared to the group\*habituation interaction in the ERP. The group\*intensity interaction effect is situated in the latency range of the P3 and probably can be replicated using peak amplitudes. The group\*habituation effect, however, is situated after the P3 and, as a

The Use of Event-Related Potentials in Chronic Back Pain Patients 135

In conclusion, without doubting the importance of maximized data derived from peak analyses, one could express doubt whether this approach represents too large a reduction and oversimplification of the post-stimulus cortical processing. In this respect, the present alternative method seems to be more appropriate. A direct comparison of the methods is difficult, if not impossible, since the ERFIA method is based on fixed latency intervals for all trials, whereas in the peak method, the latency of the maximum amplitude differs per trial. Future research has to clarify when to use peak amplitude analysis and in which situations a

Using ERP measures, many interesting insights in cortical processing of pain are emerging, such as habituation processes, genetic influences, and influences of personality. These phenomena may contribute to finding explanations for the transition of acute pain to chronic (low back) pain states. Nevertheless, longitudinal research designs are necessary to study this process in detail, as well as a combination of ERP with other methods, such as fMRI, and magnetoencephalography. Furthermore, the application of mixed regression will enable a better understanding of the variance in the pain-ERP. Once the pain-ERP and its underlying cortical processes are understood more completely, the path to remediation in

We are grateful to Jacco Ronner and his colleagues, Department of Instrumentation, Faculty of Psychology and Neuroscience, Maastricht University, for their technical assistance and

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clinical practice is open. Then, development of diagnostic tools could be in reach.

**6. Conclusion** 

fixed-AUC method is more suitable.

**7. Acknowledgments** 

pp. 15-28.

programming.

**8. References** 

consequence, most likely can not be found in peak analyses. These off-peak effects may be valuable in the search for chronification mechanisms.

All group interaction effects are based on a contrast of a subclinical CLBP population to pain free-controls. The choice of this CLBP group may be disputed, since this subclinical group is likely to be heterogeneous with respect to underlying pathology. Nonetheless, the CLBP group clearly differs from the control group with regard to the key variable pain (see Table 1). The analyses of the ERFIA segments seem to produce more pronounced and significant results, compared to the peak results published by Vossen (2010c). This can be concluded not only from the very large T-values (up to 14) but also from the prolonged latency effects. A typical example is the very broad latency window (from 160-420 ms) of the main effect on intensity. Also, effects of linear habituation are significantly embedded in a large range of consecutive ERFIA segments. Interestingly, intensity of a previous stimulus, indicative for a 'memory' of painful events, showed a significant long-lasting influence (see Figure 5). Since no apparent peaks emerge after 300 ms in the averaged pain-ERP (see Figure 1), The ERFIA method seems to be more useful to detect such late effects than the peak method. This is demonstrated by the fact that we could not find a main effect of the previous stimulus intensity in earlier analyses (Vossen et al., 2011). By plotting the T-values of consecutive ERFIAs, we observed another advantage in the interpretation of the results. In time, variables become more significant and reach a 'peak significance,' followed by a decrease. This information gives insight into the start and end of an influential effect of a variable. To illustrate, intensity seems to have two main effects in the latency range of 140-400 ms. One could speculate that this T-value graph (Figure 3) is indicative for two 'intensity' processes.

Some critical aspects need to be considered in the application of the proposed ERFIA method. First, a large number of consecutive ERFIA segments may result in an unacceptable number of statistical tests. In our view, a rigid correction method for multiple testing, such as the Bonferroni correction, would increase the risk of rejecting 'real' effects in this early, explorative phase of the study. However, an appropriate correction for multiple testing is required. Another critical point concerns the optimal width of ERFIAs. In the present study, we used fixed segments of 20 ms. In order to get a general impression of effects within a relatively large window (500 ms or more), we judge the 20-ms criterion to be appropriate. When investigating small effects, one could argue for the use of smaller areas. Enlargement of the width would reduce the number of tests but may introduce more noise. A third note is related to EOG rejection. In the present analyses, we used a ±25-μV criterion to reject AUCs. It remains to be investigated whether this criterion is optimal. In handling confounded EOG segments, the use of multilevel analyses is especially worthwhile, since all valid, analyzable segments are included, whereas in analysis of variance, a whole subject would have been excluded in the case of too many invalid segments. Finally, one major disadvantage of both peak and AUC measures is the poor spatial resolution. Other techniques in analyzing ERP have been developed to overcome this problem. As an example, probabilistic independent component analysis (PICA) has been applied to gain more insight in the source of underlying multimodal and modality-specific neural activities (Jung et al., 2001; Makeigh et al., 1997; Mouraux et al., 2009). Also, many fMRI studies and magnetoencephalography studies are emerging, with high spatial resolution (Bromm, 2001; Makeig, 004; Stancak et al., 2011; Peyron et al., 2000). Combining ERP methods with fMRI will allow investigation of pain processing in a temporal as well as a spatial superior fashion.

#### **6. Conclusion**

134 Low Back Pain

consequence, most likely can not be found in peak analyses. These off-peak effects may be

All group interaction effects are based on a contrast of a subclinical CLBP population to pain free-controls. The choice of this CLBP group may be disputed, since this subclinical group is likely to be heterogeneous with respect to underlying pathology. Nonetheless, the CLBP group clearly differs from the control group with regard to the key variable pain (see Table 1). The analyses of the ERFIA segments seem to produce more pronounced and significant results, compared to the peak results published by Vossen (2010c). This can be concluded not only from the very large T-values (up to 14) but also from the prolonged latency effects. A typical example is the very broad latency window (from 160-420 ms) of the main effect on intensity. Also, effects of linear habituation are significantly embedded in a large range of consecutive ERFIA segments. Interestingly, intensity of a previous stimulus, indicative for a 'memory' of painful events, showed a significant long-lasting influence (see Figure 5). Since no apparent peaks emerge after 300 ms in the averaged pain-ERP (see Figure 1), The ERFIA method seems to be more useful to detect such late effects than the peak method. This is demonstrated by the fact that we could not find a main effect of the previous stimulus intensity in earlier analyses (Vossen et al., 2011). By plotting the T-values of consecutive ERFIAs, we observed another advantage in the interpretation of the results. In time, variables become more significant and reach a 'peak significance,' followed by a decrease. This information gives insight into the start and end of an influential effect of a variable. To illustrate, intensity seems to have two main effects in the latency range of 140-400 ms. One could speculate that this T-value graph (Figure 3) is indicative for two 'intensity' processes. Some critical aspects need to be considered in the application of the proposed ERFIA method. First, a large number of consecutive ERFIA segments may result in an unacceptable number of statistical tests. In our view, a rigid correction method for multiple testing, such as the Bonferroni correction, would increase the risk of rejecting 'real' effects in this early, explorative phase of the study. However, an appropriate correction for multiple testing is required. Another critical point concerns the optimal width of ERFIAs. In the present study, we used fixed segments of 20 ms. In order to get a general impression of effects within a relatively large window (500 ms or more), we judge the 20-ms criterion to be appropriate. When investigating small effects, one could argue for the use of smaller areas. Enlargement of the width would reduce the number of tests but may introduce more noise. A third note is related to EOG rejection. In the present analyses, we used a ±25-μV criterion to reject AUCs. It remains to be investigated whether this criterion is optimal. In handling confounded EOG segments, the use of multilevel analyses is especially worthwhile, since all valid, analyzable segments are included, whereas in analysis of variance, a whole subject would have been excluded in the case of too many invalid segments. Finally, one major disadvantage of both peak and AUC measures is the poor spatial resolution. Other techniques in analyzing ERP have been developed to overcome this problem. As an example, probabilistic independent component analysis (PICA) has been applied to gain more insight in the source of underlying multimodal and modality-specific neural activities (Jung et al., 2001; Makeigh et al., 1997; Mouraux et al., 2009). Also, many fMRI studies and magnetoencephalography studies are emerging, with high spatial resolution (Bromm, 2001; Makeig, 004; Stancak et al., 2011; Peyron et al., 2000). Combining ERP methods with fMRI will allow investigation of pain processing in a temporal as well as a spatial superior

valuable in the search for chronification mechanisms.

fashion.

In conclusion, without doubting the importance of maximized data derived from peak analyses, one could express doubt whether this approach represents too large a reduction and oversimplification of the post-stimulus cortical processing. In this respect, the present alternative method seems to be more appropriate. A direct comparison of the methods is difficult, if not impossible, since the ERFIA method is based on fixed latency intervals for all trials, whereas in the peak method, the latency of the maximum amplitude differs per trial. Future research has to clarify when to use peak amplitude analysis and in which situations a fixed-AUC method is more suitable.

Using ERP measures, many interesting insights in cortical processing of pain are emerging, such as habituation processes, genetic influences, and influences of personality. These phenomena may contribute to finding explanations for the transition of acute pain to chronic (low back) pain states. Nevertheless, longitudinal research designs are necessary to study this process in detail, as well as a combination of ERP with other methods, such as fMRI, and magnetoencephalography. Furthermore, the application of mixed regression will enable a better understanding of the variance in the pain-ERP. Once the pain-ERP and its underlying cortical processes are understood more completely, the path to remediation in clinical practice is open. Then, development of diagnostic tools could be in reach.

#### **7. Acknowledgments**

We are grateful to Jacco Ronner and his colleagues, Department of Instrumentation, Faculty of Psychology and Neuroscience, Maastricht University, for their technical assistance and programming.

#### **8. References**


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**7** 

*Belgium* 

Christophe Demoulin\*\* et al.\* *Department of Motricity Sciences,* 

**Muscular Performance Assessment of Trunk** 

*Liege University and Liege University Hospital Centre (CHU),* 

**Extensors: A Critical Appraisal of the Literature** 

Despite growing research efforts, non-specific low back pain (LBP) remains a major public health burden throughout the industrialized world. Epidemiological data indicate a point prevalence ranging from 19% (Hillman et al., 1996) to 27% (Picavet & Schouten, 2003) and a lifetime prevalence of about 60% (Hillman et al., 1996). Costs to society stem mainly from

Some literature suggests that muscle dysfunction or increased fatigability might jeopardize the function of the spine and be a risk factor in the development, persistence or recurrence of LBP (Biering-Sorensen, 1984; Parnianpour et al., 1988; Alaranta et al., 1995; Hides et al., 1996). Besides, several studies suggest that patients with chronic low back pain (CLBP) may benefit from an active multidisciplinary approach involving an individually tailored reconditioning program (Bendix et al., 1998; Smeets et al., 2008; Demoulin et al., 2010); some authors even reported benefits of programs based mainly on trunk muscles training (Manniche et al., 1988; Mooney et al., 1995; Nelson et al., 1995; Carpenter & Nelson, 1999; Mannion et al., 1999b). As a result, tests of trunk muscle performance are essential to get insight in the muscle strength/endurance. Furthermore, accurate evaluation of patients' deficiencies is essential for the planning of a successful rehabilitation program, for documenting program efficacy and for providing the patients with information on their physical potential and ability to make progress, thereby leading to favourable behavioural changes. Therefore, several reviews have been published targeting performance of trunk muscles (Beimborn & Morrissey, 1988; Newton & Waddell, 1993; Moreau et al., 2001; Malliou et al., 2006). Currently, assessments are performed by means of various methods and no consensus has been reached regarding the optimal test to be used. Most of the time, assessment of trunk extensors has been performed by means of maximum effort tests;

Stéphanie Grosdent1,\*\*, Rob Smeets2, Jeanine Verbunt2, Boris Jidovtseff1, Geneviève Mahieu3,\*\*,

*Medical Centre, Adelante, Centre of Expertise in Rehabilitation and Audiology, The Netherlands* 

*1 Department of Motricity Sciences, Liege University and Liege University Hospital Centre (CHU), Belgium 2 Department of Rehabilitation Medicine, School of Caphri, Maastricht University and Maastricht University* 

Jean-Michel Crielaard1,\*\*, Marc Vanderthommen1,\*\*

*3 Back Unit, Dinant Hospital Centre, Belgium \*\* Member of the Belgian Back Society*

chronic forms, which account for only 5–10% of cases (Nachemson et al., 2000).

**1. Introduction** 

 \*


### **Muscular Performance Assessment of Trunk Extensors: A Critical Appraisal of the Literature**

Christophe Demoulin\*\* et al.\*

*Department of Motricity Sciences, Liege University and Liege University Hospital Centre (CHU), Belgium* 

#### **1. Introduction**

140 Low Back Pain

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potentials. *Pain*, Vol.66, pp. 39-49.

pp. 311–315.

Vol.299, pp. 1240–1243.

Despite growing research efforts, non-specific low back pain (LBP) remains a major public health burden throughout the industrialized world. Epidemiological data indicate a point prevalence ranging from 19% (Hillman et al., 1996) to 27% (Picavet & Schouten, 2003) and a lifetime prevalence of about 60% (Hillman et al., 1996). Costs to society stem mainly from chronic forms, which account for only 5–10% of cases (Nachemson et al., 2000).

Some literature suggests that muscle dysfunction or increased fatigability might jeopardize the function of the spine and be a risk factor in the development, persistence or recurrence of LBP (Biering-Sorensen, 1984; Parnianpour et al., 1988; Alaranta et al., 1995; Hides et al., 1996). Besides, several studies suggest that patients with chronic low back pain (CLBP) may benefit from an active multidisciplinary approach involving an individually tailored reconditioning program (Bendix et al., 1998; Smeets et al., 2008; Demoulin et al., 2010); some authors even reported benefits of programs based mainly on trunk muscles training (Manniche et al., 1988; Mooney et al., 1995; Nelson et al., 1995; Carpenter & Nelson, 1999; Mannion et al., 1999b). As a result, tests of trunk muscle performance are essential to get insight in the muscle strength/endurance. Furthermore, accurate evaluation of patients' deficiencies is essential for the planning of a successful rehabilitation program, for documenting program efficacy and for providing the patients with information on their physical potential and ability to make progress, thereby leading to favourable behavioural changes. Therefore, several reviews have been published targeting performance of trunk muscles (Beimborn & Morrissey, 1988; Newton & Waddell, 1993; Moreau et al., 2001; Malliou et al., 2006). Currently, assessments are performed by means of various methods and no consensus has been reached regarding the optimal test to be used. Most of the time, assessment of trunk extensors has been performed by means of maximum effort tests;

<sup>\*</sup> Stéphanie Grosdent1,\*\*, Rob Smeets2, Jeanine Verbunt2, Boris Jidovtseff1, Geneviève Mahieu3,\*\*, Jean-Michel Crielaard1,\*\*, Marc Vanderthommen1,\*\*

*<sup>1</sup> Department of Motricity Sciences, Liege University and Liege University Hospital Centre (CHU), Belgium 2 Department of Rehabilitation Medicine, School of Caphri, Maastricht University and Maastricht University* 

*Medical Centre, Adelante, Centre of Expertise in Rehabilitation and Audiology, The Netherlands 3 Back Unit, Dinant Hospital Centre, Belgium* 

*<sup>\*\*</sup> Member of the Belgian Back Society*

Muscular Performance Assessment of Trunk Extensors: A Critical Appraisal of the Literature 143

methodological variations can affect muscle activity considerably (Mayer et al., 1999; Champagne et al., 2008) and result in considerable discrepancies in study findings. However, concordance was found between some studies regarding the mean holding time in healthy subjects: whereas Latimer et al. measured a holding time of 133s in mixed males and females (Latimer et al., 1999), Mannion et al. reported a holding time reaching 142s and 116s in females and males, respectively (Mannion & Dolan, 1994). Such a gender-related difference was reported in most other studies (Biering-Sorensen, 1984; Mannion et al., 1997a; Kankaanpaa et al., 1998a; McGill et al., 1999; Muller et al., 2010). Differences between genders regarding the weight of the upper body, the degree of lumbar lordosis, the muscles composition (Demoulin et al., 2006b) and the neuromuscular activation patterns (Lariviere

The Sorensen test has sometimes been considered as a specific tool for evaluating the back muscles (Alaranta et al., 1995). Although spinal muscles are really solicited, most notably the multifidus muscle (Ng et al., 1997; Coorevits et al., 2008; Muller et al., 2010), the test solicits also the other muscles involved in extension of the trunk i.e. the hip extensor muscles (Kankaanpaa et al., 1998a; Plamondon et al., 2002; Plamondon et al., 2004; Champagne et al., 2008; Coorevits et al., 2008; Muller et al., 2010). However muscle fatigue of the hip extensor muscles (reflected by electromyographic parameters) is less correlated to the test holding

Although some authors call it a "strength test" (Salminen et al., 1992; Tekin et al., 2009), it rather assesses muscle static endurance (Crowther et al., 2007). Indeed, the elicited contractions were found to be no greater than 40-52% of the maximal voluntary contraction (MVC) (Mannion & Dolan, 1994; Ng et al., 1997; Plamondon et al., 1999; Muller et al., 2010) and the electromyographic (EMG) activity of the spinal erector muscles rarely exceeded 40%

Although the reproducibility of the Sorensen test has been evaluated in several studies, most of these suffered from methodological weakness (Essendrop et al., 2002; Demoulin et al., 2006b). In general, investigations reported a moderate or high† intra-session, intersession and inter-tester reproducibility (Simmonds et al., 1998; Latimer et al., 1999; Demoulin et al., 2008b; Gruther et al., 2009), except in case a Roman chair was used (Mayer et al., 1995; Keller et al., 2001). Although the reproducibility is satisfactory in patients with LBP (Simmonds et al., 1998; Latimer et al., 1999) it might be relevant to repeat the test twice (with a 15-minute rest in between) to avoid a learning effect which has been found in some

Most studies have reported a good discriminative validity of the Sorensen test reflected by a holding-time being significantly lower in patients with LBP compared to healthy subjects (Biering-Sorensen, 1984; Hultman et al., 1993; Simmonds et al., 1998; Latimer et al., 1999; Ljungquist et al., 1999; Arab et al., 2007; Gruther et al., 2009). The safety of the test has also been investigated. A small number of subjects reported back pain during the test (Demoulin et al., 2008b; Demoulin et al., 2009), sometimes resulting in the interruption of the test (Biering-Sorensen, 1984; Latikka et al., 1995; Latimer et al., 1999); however, no persistent adverse effects have been reported following the test (Simmonds et al., 1998; Demoulin et

† based on the classification of Wind et al. (J Occup Rehabil, 2005, 15(2):253-272) which will also be used

et al., 2006) are all hypotheses mentioned.

patients (Demoulin et al., 2008b).

in the rest of the chapter.

time than back muscle fatigue (Coorevits et al., 2008).

of its maximal value (Plamondon et al., 1999; Plamondon et al., 2002).

however, alternatives to maximum effort tests have also been developed. Therefore the aim of the current review is to present a critical appraisal of the literature on this topic.

#### **2. Assessment of trunk extensors by means of maximum effort tests**

#### **2.1 Non-dynamometric tests**

Trunk extensor performance has been measured with clinical tests for more than 50 years (Hansen, 1964). These tests, which usually assess endurance of trunk extensors, have the main advantages that they don't require specific equipment, are inexpensive, quick and easy to perform. However, they are not adapted to assess muscle strength and they do not provide a stabilization system to limit hip extensors activation (making them unable to assess spinal muscles specifically). These tests have most often been used in healthy subjects and in patients with CLBP, but they have also been used in other populations (e.g. patients after back surgery (Hakkinen et al., 2003), in schoolchildren (Salminen et al., 1992), etc.).

#### **2.1.1 Static tests**

The **Sorensen test** is by far the most widely used and studied test for assessing trunk extensor muscles (Demoulin et al., 2006b). In this test, the subject lies on an examining table in the prone position with the pelvis aligned with the edge of the table. Calves, thighs, and buttocks are secured and upon command, the subject is asked to maintain the horizontal position as long as possible with the arms folded across the chest (Fig 1a). This test was first described by Hansen in 1964 (Hansen, 1964), but it became known as the "Sorensen test" following a study by Biering-Sorensen in 1984, according to which good isometric endurance might prevent first-time LBP occurrence (Biering-Sorensen, 1984). Although some authors have reported similar findings (Alaranta et al., 1995; Adams et al., 1999; Sjolie & Ljunggren, 2001), such association was not confirmed in other studies (Salminen et al., 1995; Gibbons et al., 1997b; Hamberg-van Reenen et al., 2006).

Fig. 1a. Original Sorensen test Fig. 1b. Sorensen test with a Roman chair

Since 1984, the Sorensen test has been used in several studies, either in its original or in adapted versions: the differences concerned the arm position, number of straps, criteria for stopping the test, etc. (Demoulin et al., 2006b); the test has also been performed on a roman chair (Fig 1b) in a few studies (Hultman et al., 1993; Mayer et al., 1995; Keller et al., 2001), sometimes with 45 degrees of hip flexion (Champagne et al., 2008). These numerous

a) b)

however, alternatives to maximum effort tests have also been developed. Therefore the aim

Trunk extensor performance has been measured with clinical tests for more than 50 years (Hansen, 1964). These tests, which usually assess endurance of trunk extensors, have the main advantages that they don't require specific equipment, are inexpensive, quick and easy to perform. However, they are not adapted to assess muscle strength and they do not provide a stabilization system to limit hip extensors activation (making them unable to assess spinal muscles specifically). These tests have most often been used in healthy subjects and in patients with CLBP, but they have also been used in other populations (e.g. patients after back surgery (Hakkinen et al., 2003), in schoolchildren (Salminen et al., 1992), etc.).

The **Sorensen test** is by far the most widely used and studied test for assessing trunk extensor muscles (Demoulin et al., 2006b). In this test, the subject lies on an examining table in the prone position with the pelvis aligned with the edge of the table. Calves, thighs, and buttocks are secured and upon command, the subject is asked to maintain the horizontal position as long as possible with the arms folded across the chest (Fig 1a). This test was first described by Hansen in 1964 (Hansen, 1964), but it became known as the "Sorensen test" following a study by Biering-Sorensen in 1984, according to which good isometric endurance might prevent first-time LBP occurrence (Biering-Sorensen, 1984). Although some authors have reported similar findings (Alaranta et al., 1995; Adams et al., 1999; Sjolie & Ljunggren, 2001), such association was not confirmed in other studies (Salminen et al.,

1995; Gibbons et al., 1997b; Hamberg-van Reenen et al., 2006).

a) b)

Fig. 1a. Original Sorensen test Fig. 1b. Sorensen test with a Roman chair

Since 1984, the Sorensen test has been used in several studies, either in its original or in adapted versions: the differences concerned the arm position, number of straps, criteria for stopping the test, etc. (Demoulin et al., 2006b); the test has also been performed on a roman chair (Fig 1b) in a few studies (Hultman et al., 1993; Mayer et al., 1995; Keller et al., 2001), sometimes with 45 degrees of hip flexion (Champagne et al., 2008). These numerous

of the current review is to present a critical appraisal of the literature on this topic.

**2. Assessment of trunk extensors by means of maximum effort tests** 

**2.1 Non-dynamometric tests** 

**2.1.1 Static tests** 

methodological variations can affect muscle activity considerably (Mayer et al., 1999; Champagne et al., 2008) and result in considerable discrepancies in study findings. However, concordance was found between some studies regarding the mean holding time in healthy subjects: whereas Latimer et al. measured a holding time of 133s in mixed males and females (Latimer et al., 1999), Mannion et al. reported a holding time reaching 142s and 116s in females and males, respectively (Mannion & Dolan, 1994). Such a gender-related difference was reported in most other studies (Biering-Sorensen, 1984; Mannion et al., 1997a; Kankaanpaa et al., 1998a; McGill et al., 1999; Muller et al., 2010). Differences between genders regarding the weight of the upper body, the degree of lumbar lordosis, the muscles composition (Demoulin et al., 2006b) and the neuromuscular activation patterns (Lariviere et al., 2006) are all hypotheses mentioned.

The Sorensen test has sometimes been considered as a specific tool for evaluating the back muscles (Alaranta et al., 1995). Although spinal muscles are really solicited, most notably the multifidus muscle (Ng et al., 1997; Coorevits et al., 2008; Muller et al., 2010), the test solicits also the other muscles involved in extension of the trunk i.e. the hip extensor muscles (Kankaanpaa et al., 1998a; Plamondon et al., 2002; Plamondon et al., 2004; Champagne et al., 2008; Coorevits et al., 2008; Muller et al., 2010). However muscle fatigue of the hip extensor muscles (reflected by electromyographic parameters) is less correlated to the test holding time than back muscle fatigue (Coorevits et al., 2008).

Although some authors call it a "strength test" (Salminen et al., 1992; Tekin et al., 2009), it rather assesses muscle static endurance (Crowther et al., 2007). Indeed, the elicited contractions were found to be no greater than 40-52% of the maximal voluntary contraction (MVC) (Mannion & Dolan, 1994; Ng et al., 1997; Plamondon et al., 1999; Muller et al., 2010) and the electromyographic (EMG) activity of the spinal erector muscles rarely exceeded 40% of its maximal value (Plamondon et al., 1999; Plamondon et al., 2002).

Although the reproducibility of the Sorensen test has been evaluated in several studies, most of these suffered from methodological weakness (Essendrop et al., 2002; Demoulin et al., 2006b). In general, investigations reported a moderate or high† intra-session, intersession and inter-tester reproducibility (Simmonds et al., 1998; Latimer et al., 1999; Demoulin et al., 2008b; Gruther et al., 2009), except in case a Roman chair was used (Mayer et al., 1995; Keller et al., 2001). Although the reproducibility is satisfactory in patients with LBP (Simmonds et al., 1998; Latimer et al., 1999) it might be relevant to repeat the test twice (with a 15-minute rest in between) to avoid a learning effect which has been found in some patients (Demoulin et al., 2008b).

Most studies have reported a good discriminative validity of the Sorensen test reflected by a holding-time being significantly lower in patients with LBP compared to healthy subjects (Biering-Sorensen, 1984; Hultman et al., 1993; Simmonds et al., 1998; Latimer et al., 1999; Ljungquist et al., 1999; Arab et al., 2007; Gruther et al., 2009). The safety of the test has also been investigated. A small number of subjects reported back pain during the test (Demoulin et al., 2008b; Demoulin et al., 2009), sometimes resulting in the interruption of the test (Biering-Sorensen, 1984; Latikka et al., 1995; Latimer et al., 1999); however, no persistent adverse effects have been reported following the test (Simmonds et al., 1998; Demoulin et

<sup>†</sup> based on the classification of Wind et al. (J Occup Rehabil, 2005, 15(2):253-272) which will also be used in the rest of the chapter.

Muscular Performance Assessment of Trunk Extensors: A Critical Appraisal of the Literature 145

many times as possible at a determined rate of arch-ups per minute (Fig. 3) (Alaranta et al., 1994; Gronblad et al., 1997; Moreland et al., 1997; Udermann et al., 2003). Whereas the static tests have been widely studied, the dynamic tests have received less attention and have been performed in various ways regarding the support (examination table, roman chair, etc.), the range of motion, the rate per minute, etc. As the original Sorensen test, the dynamic tests are not specifically testing the back muscles (Konrad et al., 2001). Although moderate reliability is suggested (Alaranta et al., 1994; Moreland et al., 1997), little is known about the other clinimetric properties of such tests. Furthermore, a recent study, which compared the static Sorensen test with its dynamic variant, revealed that the latter was less comfortable and more difficult to standardize (Demoulin et al., 2008b). In a few studies, the subjects were asked to perform as many repetitions as possible in 30 seconds (Viljanen et al., 1991; Kujala

Today, various dynamometric testing machines have been developed to assess trunk muscle performance: these tests allow more complete, precise and specific assessments than the non-dynamometric tests. These measurement systems, also designed to train muscles, differ in terms of contraction mode (static, isotonic, isokinetic), subject position (standing, sitting,

MVC tests of trunk extensor muscles have been used in several studies to assess maximal strength in healthy subjects and patients with LBP but also in other populations (e.g. patients following back surgery (Hakkinen et al., 2003), elderly subjects (Rantanen et al., 1997), etc.). Patients with CLBP had reduced values compared to healthy controls in most studies (Reid et al., 1991; Hultman et al., 1993; Kankaanpaa et al., 1998b; Handa et al., 2000; Bayramoglu et al., 2001; Kramer et al., 2005; Gruther et al., 2009), but not all studies (Shirado et al., 1992; Cassisi et al., 1993; Takemasa et al., 1995; da Silva et al., 2005). Several methods

lying prone) etc., and generally enable the assessment of several muscular qualities.

et al., 1996).

Fig. 3. Arch-up test

**2.2 Dynamometric tests** 

**2.2.1 Muscle strength tests** 

(see below) have been used for testing maximal strength.

al., 2008b) and it could even be applied in elderly people (Champagne et al., 2009). In view of the stress induced on the cardiovascular system, the Sorensen test might better be avoided in patients suffering from cardiovascular disease because of a pressure overload of the cardiovascular system (Suni et al., 1998; Demoulin et al., 2009).

The **Ito test,** sometimes called "prone isometric chest raise test", has been described in a couple of studies (Shirado et al., 1995b; Ito et al., 1996; Arab et al., 2007; Durmus et al., 2009; Muller et al., 2010); it consists of lifting the upper body while lying prone with a pad under the abdomen, the arms along the sides, the neck flexed as much as possible and the gluteus maximus muscles contracted for stabilizing the pelvis (Fig. 2a) (Shirado et al., 1995b); this position has to be held as long as possible (Ito et al., 1996). Its discriminative power and high reproducibility were reported in the original study (Ito et al., 1996); furthermore, fatigue of the iliocostalis and the multifidi has clearly been linked to the holding time (Muller et al., 2010). Although this test is attractive because it is easy to perform and because it seems to induce less spine loading and limit the risk of lumbar hyperlordosis as compared to the Sorensen test (Ito et al., 1996), no study really confirmed this assumption. Furthermore, a study suggested that this test was less comfortable and more difficult to standardize (with regard to the extent of the upper body lift) than the Sorensen test (Demoulin et al., 2008b). These differences might explain the controversial correlations found when comparing holding times of both tests (Demoulin et al., 2008b; Muller et al., 2010).

The **prone double straight-leg raise test** has been described for evaluating the isometric endurance of the lower spinal extensor muscles (McIntosh et al., 1998; Moreau et al., 2001). In this test, the subject lies prone with hips extended and the hands underneath the forehead (Fig. 2b). The subject is asked to raise both legs until knee clearance as long as possible. According to Arab et al., this test is as reproducible as the other static endurance tests and has good sensitivity, specificity and predictive values in LBP (Arab et al., 2007). However, information about its validity, safety and responsiveness is lacking.

a) b)

Fig. 2. a) Ito test, b) Prone double straight-leg raise test

#### **2.1.2 Dynamic tests ("arch-up tests")**

The "arch-up tests", sometimes considered as dynamic variants of the Sorensen test, are usually used to assess dynamic endurance of trunk extensors. These tests, performed with the subject prone with the torso cantilevered over the edge of a table, consist in flexing the trunk to a specific position (e.g. 30° trunk flexion), then returning to the initial position as many times as possible at a determined rate of arch-ups per minute (Fig. 3) (Alaranta et al., 1994; Gronblad et al., 1997; Moreland et al., 1997; Udermann et al., 2003). Whereas the static tests have been widely studied, the dynamic tests have received less attention and have been performed in various ways regarding the support (examination table, roman chair, etc.), the range of motion, the rate per minute, etc. As the original Sorensen test, the dynamic tests are not specifically testing the back muscles (Konrad et al., 2001). Although moderate reliability is suggested (Alaranta et al., 1994; Moreland et al., 1997), little is known about the other clinimetric properties of such tests. Furthermore, a recent study, which compared the static Sorensen test with its dynamic variant, revealed that the latter was less comfortable and more difficult to standardize (Demoulin et al., 2008b). In a few studies, the subjects were asked to perform as many repetitions as possible in 30 seconds (Viljanen et al., 1991; Kujala et al., 1996).

Fig. 3. Arch-up test

144 Low Back Pain

al., 2008b) and it could even be applied in elderly people (Champagne et al., 2009). In view of the stress induced on the cardiovascular system, the Sorensen test might better be avoided in patients suffering from cardiovascular disease because of a pressure overload of

The **Ito test,** sometimes called "prone isometric chest raise test", has been described in a couple of studies (Shirado et al., 1995b; Ito et al., 1996; Arab et al., 2007; Durmus et al., 2009; Muller et al., 2010); it consists of lifting the upper body while lying prone with a pad under the abdomen, the arms along the sides, the neck flexed as much as possible and the gluteus maximus muscles contracted for stabilizing the pelvis (Fig. 2a) (Shirado et al., 1995b); this position has to be held as long as possible (Ito et al., 1996). Its discriminative power and high reproducibility were reported in the original study (Ito et al., 1996); furthermore, fatigue of the iliocostalis and the multifidi has clearly been linked to the holding time (Muller et al., 2010). Although this test is attractive because it is easy to perform and because it seems to induce less spine loading and limit the risk of lumbar hyperlordosis as compared to the Sorensen test (Ito et al., 1996), no study really confirmed this assumption. Furthermore, a study suggested that this test was less comfortable and more difficult to standardize (with regard to the extent of the upper body lift) than the Sorensen test (Demoulin et al., 2008b). These differences might explain the controversial correlations found when comparing

The **prone double straight-leg raise test** has been described for evaluating the isometric endurance of the lower spinal extensor muscles (McIntosh et al., 1998; Moreau et al., 2001). In this test, the subject lies prone with hips extended and the hands underneath the forehead (Fig. 2b). The subject is asked to raise both legs until knee clearance as long as possible. According to Arab et al., this test is as reproducible as the other static endurance tests and has good sensitivity, specificity and predictive values in LBP (Arab et al., 2007). However,

the cardiovascular system (Suni et al., 1998; Demoulin et al., 2009).

holding times of both tests (Demoulin et al., 2008b; Muller et al., 2010).

information about its validity, safety and responsiveness is lacking.

a) b)

The "arch-up tests", sometimes considered as dynamic variants of the Sorensen test, are usually used to assess dynamic endurance of trunk extensors. These tests, performed with the subject prone with the torso cantilevered over the edge of a table, consist in flexing the trunk to a specific position (e.g. 30° trunk flexion), then returning to the initial position as

Fig. 2. a) Ito test, b) Prone double straight-leg raise test

**2.1.2 Dynamic tests ("arch-up tests")** 

#### **2.2 Dynamometric tests**

Today, various dynamometric testing machines have been developed to assess trunk muscle performance: these tests allow more complete, precise and specific assessments than the non-dynamometric tests. These measurement systems, also designed to train muscles, differ in terms of contraction mode (static, isotonic, isokinetic), subject position (standing, sitting, lying prone) etc., and generally enable the assessment of several muscular qualities.

#### **2.2.1 Muscle strength tests**

MVC tests of trunk extensor muscles have been used in several studies to assess maximal strength in healthy subjects and patients with LBP but also in other populations (e.g. patients following back surgery (Hakkinen et al., 2003), elderly subjects (Rantanen et al., 1997), etc.). Patients with CLBP had reduced values compared to healthy controls in most studies (Reid et al., 1991; Hultman et al., 1993; Kankaanpaa et al., 1998b; Handa et al., 2000; Bayramoglu et al., 2001; Kramer et al., 2005; Gruther et al., 2009), but not all studies (Shirado et al., 1992; Cassisi et al., 1993; Takemasa et al., 1995; da Silva et al., 2005). Several methods (see below) have been used for testing maximal strength.

Muscular Performance Assessment of Trunk Extensors: A Critical Appraisal of the Literature 147

Most studies concerned the MedX™ (MedX Corp. Ocala, FL, USA) which is a dynamometer developed to assess and train spinal muscles (Graves et al., 1990) (Fig. 5). MedX™ assessment consists of measuring the extensor isometric MVC at 7 angles of trunk flexion within the patient's range of motion (i.e. 0-12-24-36-48-60-72°) (Graves et al., 1990). This device is unique in the fact that it uses a gravity correction system (Pollock et al., 1991; Graves et al., 1994). Literature suggests a moderate to high reproducibility of peak torque values in healthy

Other companies (David, Tergumed, Schnell, DBC) propose a complete set of four individual units for training (Taimela & Harkapaa, 1996; Daniels & Denner, 1999; Mannion et al., 1999b; Giemza et al., 2006) and assessing the trunk extensor, flexor, rotator and lateralflexor muscles, respectively (Demoulin et al., 2006a; Roussel et al., 2008). The extension device (Fig. 5) differs between the various systems of the companies regarding the hip stabilization system, position of the thighs, legs and feet, etc. Although these protocol differences might concur meaningful inter-system comparison, significant correlations were observed between the MVCs measured by the David, Tergumed and Schnell systems as well when considering the absolute values (r 0.8) as when considering the relative values expressed in percentage of specific normative data (r 0.69) (Demoulin et al., 2008a). Although spinal muscles seem to be well activated (80% maximal EMG activity) during an isometric extension MVC on such dynamometers (Denner, 1997; Vanderthommen et al., 2007), a significant activation of hip extensor muscles has also been observed (about 50% of maximal EMG activity) (Vanderthommen et al., 2007). Several authors reported a high intersession (Elfving et al., 1999; Demoulin et al., 2006a) and inter-tester (Demoulin et al., 2006a) reproducibility of MVC measurements in healthy subjects and in patients with CLBP (Elfving et al., 2003; Roussel et al., 2008); however, the inter-site reproducibility (in healthy subjects) revealed small but significant differences in measurements between identical devices (Demoulin et al., 2006a). The cardiovascular stress of such maximal isometric effort seems to be limited in healthy middle-aged individuals (maximal systolic and diastolic blood pressure monitored at the end of the MVC test: 165 and 105 mmHg, respectively) (Demoulin et al., 2009); however these results need to be confirmed with instantaneous

individuals (Graves et al., 1990) and patients with CLBP (Robinson et al., 1992).

 Fig. 5. MedX™, David and Tergumed dynamometers, respectively

blood pressure measurement.

#### **2.2.1.1 Static strength test**

Usually, after a muscular warming-up and sometimes a familiarization period, the subject is instructed to build up the force with increasing intensity. In most studies, about three MVC are measured at short periods intervals; sometimes additional trials are permitted and the best result of the contractions is selected (Demoulin et al., 2006a; Schenk et al., 2006).

Trunk extensors strength can be assessed by means of a **hand-held dynamometer** that is held by the investigator in the interscapular area; the subject, lying prone, has to perform a maximal static effort against it (Fig. 4a). This test which has been confidentially described (Moreland et al., 1997; Swezey et al., 2000; Durmus et al., 2009) appears to be difficult to perform in a standardized manner (Moreland et al., 1997; Swezey et al., 2000) and has a low reproducibility (Moreland et al., 1997).

MVC of trunk extensors has also been assessed by means of a **strain gauge** (Fig. 4b) attached to a wall and connected to a strap around the shoulders; a pelvic fixation is provided so that the rotation axis is set at the hip joint level. The subject, in standing position, has to perform an isometric backward extension ("pulling test") (Biering-Sorensen, 1984; Nicolaisen & Jorgensen, 1985; Kumar et al., 1995; Kujala et al., 1996). In some studies, a more sophisticated apparatus (e.g. with a frame) has been developed (da Silva et al., 2005). Tests in sitting (Kumar et al., 1995) or in prone positions (Plamondon et al., 2004; da Silva et al., 2005) have also been described. Reliability of the pulling tests seems high to moderate (Jorgensen, 1997; Lariviere et al., 2001); however, little is known about the other clinimetric qualities.

Fig. 4. a) Hand-held dynamometer, b) "Pulling test" in standing position, c) "Pulling test" in prone position

**Specialized and commercialized equipments** have also been developed to assess and train trunk muscles. The subject is seated in the equipment and a control of the pelvis is provided by means of a stabilization system designed to limit the activation of hip extensors (Graves et al., 1994; San Juan et al., 2005; Smith et al., 2008); however relevance of such stabilization systems which differ from one device to another remains controversial (Udermann et al., 1999; Walsworth, 2004).

Usually, after a muscular warming-up and sometimes a familiarization period, the subject is instructed to build up the force with increasing intensity. In most studies, about three MVC are measured at short periods intervals; sometimes additional trials are permitted and the

Trunk extensors strength can be assessed by means of a **hand-held dynamometer** that is held by the investigator in the interscapular area; the subject, lying prone, has to perform a maximal static effort against it (Fig. 4a). This test which has been confidentially described (Moreland et al., 1997; Swezey et al., 2000; Durmus et al., 2009) appears to be difficult to perform in a standardized manner (Moreland et al., 1997; Swezey et al., 2000) and has a low

MVC of trunk extensors has also been assessed by means of a **strain gauge** (Fig. 4b) attached to a wall and connected to a strap around the shoulders; a pelvic fixation is provided so that the rotation axis is set at the hip joint level. The subject, in standing position, has to perform an isometric backward extension ("pulling test") (Biering-Sorensen, 1984; Nicolaisen & Jorgensen, 1985; Kumar et al., 1995; Kujala et al., 1996). In some studies, a more sophisticated apparatus (e.g. with a frame) has been developed (da Silva et al., 2005). Tests in sitting (Kumar et al., 1995) or in prone positions (Plamondon et al., 2004; da Silva et al., 2005) have also been described. Reliability of the pulling tests seems high to moderate (Jorgensen, 1997;

Lariviere et al., 2001); however, little is known about the other clinimetric qualities.

a) b) c)

Fig. 4. a) Hand-held dynamometer, b) "Pulling test" in standing position, c) "Pulling test" in

**Specialized and commercialized equipments** have also been developed to assess and train trunk muscles. The subject is seated in the equipment and a control of the pelvis is provided by means of a stabilization system designed to limit the activation of hip extensors (Graves et al., 1994; San Juan et al., 2005; Smith et al., 2008); however relevance of such stabilization systems which differ from one device to another remains controversial (Udermann et al.,

best result of the contractions is selected (Demoulin et al., 2006a; Schenk et al., 2006).

**2.2.1.1 Static strength test** 

reproducibility (Moreland et al., 1997).

prone position

1999; Walsworth, 2004).

Most studies concerned the MedX™ (MedX Corp. Ocala, FL, USA) which is a dynamometer developed to assess and train spinal muscles (Graves et al., 1990) (Fig. 5). MedX™ assessment consists of measuring the extensor isometric MVC at 7 angles of trunk flexion within the patient's range of motion (i.e. 0-12-24-36-48-60-72°) (Graves et al., 1990). This device is unique in the fact that it uses a gravity correction system (Pollock et al., 1991; Graves et al., 1994). Literature suggests a moderate to high reproducibility of peak torque values in healthy individuals (Graves et al., 1990) and patients with CLBP (Robinson et al., 1992).

Fig. 5. MedX™, David and Tergumed dynamometers, respectively

Other companies (David, Tergumed, Schnell, DBC) propose a complete set of four individual units for training (Taimela & Harkapaa, 1996; Daniels & Denner, 1999; Mannion et al., 1999b; Giemza et al., 2006) and assessing the trunk extensor, flexor, rotator and lateralflexor muscles, respectively (Demoulin et al., 2006a; Roussel et al., 2008). The extension device (Fig. 5) differs between the various systems of the companies regarding the hip stabilization system, position of the thighs, legs and feet, etc. Although these protocol differences might concur meaningful inter-system comparison, significant correlations were observed between the MVCs measured by the David, Tergumed and Schnell systems as well when considering the absolute values (r 0.8) as when considering the relative values expressed in percentage of specific normative data (r 0.69) (Demoulin et al., 2008a). Although spinal muscles seem to be well activated (80% maximal EMG activity) during an isometric extension MVC on such dynamometers (Denner, 1997; Vanderthommen et al., 2007), a significant activation of hip extensor muscles has also been observed (about 50% of maximal EMG activity) (Vanderthommen et al., 2007). Several authors reported a high intersession (Elfving et al., 1999; Demoulin et al., 2006a) and inter-tester (Demoulin et al., 2006a) reproducibility of MVC measurements in healthy subjects and in patients with CLBP (Elfving et al., 2003; Roussel et al., 2008); however, the inter-site reproducibility (in healthy subjects) revealed small but significant differences in measurements between identical devices (Demoulin et al., 2006a). The cardiovascular stress of such maximal isometric effort seems to be limited in healthy middle-aged individuals (maximal systolic and diastolic blood pressure monitored at the end of the MVC test: 165 and 105 mmHg, respectively) (Demoulin et al., 2009); however these results need to be confirmed with instantaneous blood pressure measurement.

Muscular Performance Assessment of Trunk Extensors: A Critical Appraisal of the Literature 149

questionable because it involves a movement in a constant speed. Limited evidence is available about the clinimetric qualities of such tests except for reliability which is high in LBP patients and healthy subjects (Newton et al., 1993; Latikka et al., 1995). The high correlations found between the isokinetic flexion-extension and lifting tests suggest that

The Isostation B-200 (Fig. 6b) has been used in a huge number of studies to assess trunk muscle performance but is less used nowadays. In addition to mobility and isometric MVC measurements, this triaxial lumbar dynamometer allows for isoinertial tests (i.e. use of a constant load throughout the range of motion) (Parnianpour et al., 1989b; Gomez et al., 1991; Balague et al., 2010). For the isoinertial flexion-repetition test, the resistance (free weights) is set at a determined percentage of the MVC of flexion (e.g. 25% or 50% (Hutten & Hermens, 1997)) for the sagittal axis and the subject is asked to bend and then return backward as fast as possible (maximum effort) about five times while functional indices (maximal or average velocity, power index and work index) can be simultaneously assessed (Gomez et al., 1991; Rytokoski et al., 1994). This assessment appears to be safe (Newton & Waddell, 1993) and reliable (Rytokoski et al., 1994) as well in healthy persons (Parnianpour et al., 1989a) as in patients with CLBP (Szpalski et al., 1992; Hutten & Hermens, 1997) except for mobility assessments. Unfortunately, axis of rotation of the device is behind the estimated axis for lumbar spine for flexion and extension (Dillard et al., 1991). Furthermore, the device might be inefficient to fully stabilize the pelvis and its relevance to improve functional physical

a) b)

Fig. 6. a) Isokinetic dynamometer, b) Isostation B-200

performing both tests is not necessary in clinical practice (Newton et al., 1993).

**2.2.1.3 Isoinertial measurements** 

capacity remains controversial (Sachs et al., 1994).

A positive relationship between lifting and LBP has been reported (Cole & Grimshaw, 2003); as a result some **functional assessments (lifting test)** have been developed to measure the strength of the functional chain (upper limbs-trunk-lower limbs) during static lifting tasks (Newton et al., 1993; Mannion et al., 1997a; da Silva et al., 2005; Ropponen, 2006). While standing and bending forward, the subject is asked to pull upward a handlebar which is fixed by a chain to a floor-mounted load cell. Methods of testing described in the literature differ regarding materials, knee flexion, the bar height, etc. Though it is a lifting task, the real functional aspect of such test remains questionable because it involves no movement; the safety of such lifting maximal isometric task remains also controversial (Hansson et al., 1984). Limited evidence is available about the clinimetric qualities of such tests.

#### **2.2.1.2 Isokinetic test**

Isokinetic dynamometry has been one of the most widely used approaches to train and measure strength of trunk muscles (Newton et al., 1993) for more than 30 years (Hasue et al., 1980). Such dynamometers can measure **trunk flexion and extension strength** (allowing to calculate agonist/antagonist ratios (Newton et al., 1993))(Fig. 6a), at various angular speeds and contraction modes (concentric most often but also eccentric (Shirado et al., 1992) and isometric (Bayramoglu et al., 2001; McGregor et al., 2004; Gruther et al., 2009)). Another advantage of isokinetic dynamometry is that it provides a variable resistance accommodating to a painful arc during the movement. Test-retest reliability of isokinetic measurements appears high in healthy subjects in most studies (Delitto et al., 1991; Newton et al., 1993; Keller et al., 2001; Karatas et al., 2002). In patients with LBP, an increase in performance between test and retest, interpreted as "learning effect", has often been reported (Grabiner et al., 1990; Newton et al., 1993; Keller et al., 2001; Gruther et al., 2009). Inter-site reliability, tested in healthy volunteers, also seems to be high (Byl & Sadowski, 1993).

However, use of isokinetic dynamometry to perform trunk muscle assessment suffers from several limitations: although some authors tried to propose a standard method of testing (Dvir & Keating, 2001), no consensus has been established yet regarding the optimal parameters for testing i.e. movement speed (which can affect testing accuracy (Keller et al., 2001)), range of motion, number of repetitions (Genty & Schmidt, 2001), etc. Differences between the existing isokinetic trunk testing machines in terms of subject position (sitting vs standing)(Morini et al., 2008), ways to reduce the artefacts, stabilization system, gravity correction system (Hupli et al., 1997; Findley et al., 2000) limit meaningful inter-system comparison (Hupli et al., 1997). Besides, the stabilization systems might be inefficient to avoid involvement of hip muscles, especially in the standing position (Morini et al., 2008). Finally, according to some authors (Ayers & Pollock, 1999), the validity of the isokinetic tests of trunk extensors remain controversial due to the impact forces at the end of the movements which can induce artefacts (overshoot). Furthermore, these tests could induce vagal disturbances (Genty & Schmidt, 2001) and pain during testing (Shirado et al., 1995a; Genty & Schmidt, 2001).

Isokinetic dynamometer has also been used to measure the **strength of the functional chain (liftask)** (Newton et al., 1993; Latikka et al., 1995; Gibbons et al., 1997b; Ropponen, 2006). As for the static lifting tests, various methods of testing have been described in the literature; besides, though it is a lifting task, the real functional aspect of such test remains questionable because it involves a movement in a constant speed. Limited evidence is available about the clinimetric qualities of such tests except for reliability which is high in LBP patients and healthy subjects (Newton et al., 1993; Latikka et al., 1995). The high correlations found between the isokinetic flexion-extension and lifting tests suggest that performing both tests is not necessary in clinical practice (Newton et al., 1993).

#### **2.2.1.3 Isoinertial measurements**

148 Low Back Pain

A positive relationship between lifting and LBP has been reported (Cole & Grimshaw, 2003); as a result some **functional assessments (lifting test)** have been developed to measure the strength of the functional chain (upper limbs-trunk-lower limbs) during static lifting tasks (Newton et al., 1993; Mannion et al., 1997a; da Silva et al., 2005; Ropponen, 2006). While standing and bending forward, the subject is asked to pull upward a handlebar which is fixed by a chain to a floor-mounted load cell. Methods of testing described in the literature differ regarding materials, knee flexion, the bar height, etc. Though it is a lifting task, the real functional aspect of such test remains questionable because it involves no movement; the safety of such lifting maximal isometric task remains also controversial (Hansson et al.,

Isokinetic dynamometry has been one of the most widely used approaches to train and measure strength of trunk muscles (Newton et al., 1993) for more than 30 years (Hasue et al., 1980). Such dynamometers can measure **trunk flexion and extension strength** (allowing to calculate agonist/antagonist ratios (Newton et al., 1993))(Fig. 6a), at various angular speeds and contraction modes (concentric most often but also eccentric (Shirado et al., 1992) and isometric (Bayramoglu et al., 2001; McGregor et al., 2004; Gruther et al., 2009)). Another advantage of isokinetic dynamometry is that it provides a variable resistance accommodating to a painful arc during the movement. Test-retest reliability of isokinetic measurements appears high in healthy subjects in most studies (Delitto et al., 1991; Newton et al., 1993; Keller et al., 2001; Karatas et al., 2002). In patients with LBP, an increase in performance between test and retest, interpreted as "learning effect", has often been reported (Grabiner et al., 1990; Newton et al., 1993; Keller et al., 2001; Gruther et al., 2009). Inter-site reliability, tested in healthy volunteers, also seems to be high (Byl & Sadowski,

However, use of isokinetic dynamometry to perform trunk muscle assessment suffers from several limitations: although some authors tried to propose a standard method of testing (Dvir & Keating, 2001), no consensus has been established yet regarding the optimal parameters for testing i.e. movement speed (which can affect testing accuracy (Keller et al., 2001)), range of motion, number of repetitions (Genty & Schmidt, 2001), etc. Differences between the existing isokinetic trunk testing machines in terms of subject position (sitting vs standing)(Morini et al., 2008), ways to reduce the artefacts, stabilization system, gravity correction system (Hupli et al., 1997; Findley et al., 2000) limit meaningful inter-system comparison (Hupli et al., 1997). Besides, the stabilization systems might be inefficient to avoid involvement of hip muscles, especially in the standing position (Morini et al., 2008). Finally, according to some authors (Ayers & Pollock, 1999), the validity of the isokinetic tests of trunk extensors remain controversial due to the impact forces at the end of the movements which can induce artefacts (overshoot). Furthermore, these tests could induce vagal disturbances (Genty & Schmidt, 2001) and pain during testing (Shirado et al., 1995a;

Isokinetic dynamometer has also been used to measure the **strength of the functional chain (liftask)** (Newton et al., 1993; Latikka et al., 1995; Gibbons et al., 1997b; Ropponen, 2006). As for the static lifting tests, various methods of testing have been described in the literature; besides, though it is a lifting task, the real functional aspect of such test remains

1984). Limited evidence is available about the clinimetric qualities of such tests.

**2.2.1.2 Isokinetic test** 

1993).

Genty & Schmidt, 2001).

The Isostation B-200 (Fig. 6b) has been used in a huge number of studies to assess trunk muscle performance but is less used nowadays. In addition to mobility and isometric MVC measurements, this triaxial lumbar dynamometer allows for isoinertial tests (i.e. use of a constant load throughout the range of motion) (Parnianpour et al., 1989b; Gomez et al., 1991; Balague et al., 2010). For the isoinertial flexion-repetition test, the resistance (free weights) is set at a determined percentage of the MVC of flexion (e.g. 25% or 50% (Hutten & Hermens, 1997)) for the sagittal axis and the subject is asked to bend and then return backward as fast as possible (maximum effort) about five times while functional indices (maximal or average velocity, power index and work index) can be simultaneously assessed (Gomez et al., 1991; Rytokoski et al., 1994). This assessment appears to be safe (Newton & Waddell, 1993) and reliable (Rytokoski et al., 1994) as well in healthy persons (Parnianpour et al., 1989a) as in patients with CLBP (Szpalski et al., 1992; Hutten & Hermens, 1997) except for mobility assessments. Unfortunately, axis of rotation of the device is behind the estimated axis for lumbar spine for flexion and extension (Dillard et al., 1991). Furthermore, the device might be inefficient to fully stabilize the pelvis and its relevance to improve functional physical capacity remains controversial (Sachs et al., 1994).

Fig. 6. a) Isokinetic dynamometer, b) Isostation B-200

#### **2.2.2 Endurance tests**

#### **2.2.2.1 Static endurance**

Muscle static endurance can be assessed with several dynamometers by measuring the time during which a subject is able to maintain a specific torque level corresponding at a preset relative percentage (often 40-60%) of the MVC previously determined (Jorgensen, 1997; Kankaanpaa et al., 1998b; Udermann et al., 2003; Demoulin et al., 2009). A visual feedback system, displaying the torque in real time, is generally positioned in front of the subject in order to keep a constant torque. This test performed in standing position, used for more than 25 years (Nicolaisen & Jorgensen, 1985), is sometimes considered to be more appropriate than the Sorensen test because it is less sensitive to heterogeneous physiques (Jorgensen, 1997; Kankaanpaa et al., 1998a; da Silva et al., 2005). Demoulin et al. compared a seated endurance test performed on a specific dynamometer (David) (Fig. 7a) to the Sorensen test in healthy subjects; they reported limited pain in the back during performance of both tests and similar subjective level of exertion and cardiovascular stress (Demoulin et al., 2009). As for the MVC test performed on this device, this seated endurance test induces hip extensors activation in spite of the hip stabilization system (Kankaanpaa et al., 1998b); unfortunately, this endurance test has a low test-retest reliability as well in healthy subjects as in patients with CLBP (Demoulin, 2008). Static endurance of trunk extensors have also been measured while the subject performs a lifting test (Mannion et al., 1997a; da Silva et al., 2005); however, such tests produce less fatigue in the back muscles than the Sorensen or the pulling tests (da Silva et al., 2005).

#### **2.2.2.2 Dynamic endurance**

Muscle dynamic endurance can be assessed with dynamometers by measuring the maximal number of repetitions performed with a specific load, with a preset speed and range of motion. The literature reports only few studies using such tests: on the David device (Fig. 7b), the load used corresponded to [0.4 x height (meter)] x [0.6 x Weight (kg)] x 0.82 (Kankaanpaa et al., 1997). This test seems to be less reproducible and well tolerated than the MVC strength and static endurance tests (Demoulin, 2008). Similar tests have been described with the Isostation B-200 (Morlock et al., 1997) and the MedX (Udermann et al., 2003).

Fig. 7. a) Static endurance test, b) Dynamic endurance test

Muscular Performance Assessment of Trunk Extensors: A Critical Appraisal of the Literature 151

Muscle fatigue can be defined as "an exercise-induced reduction in the ability of muscle to produce force or power whether or not the task can be sustained" (Enoka & Duchateau, 2008). Fatigue can be calculated by comparing the maximal strength (MVCs) prior and after an exhaustion task; in the study of Al-Obaidi et al., the task consisted in performing as many extension movements as possible against a predefined individual resistance (corresponding at 50% of the pre-MVC) (Al-Obaidi et al., 2003). Plamondon et al. submitted healthy students to an intermittent prone back extension exercise (100 dynamic repetitions) and reported fatigue of trunk extensors according to the decrease of MVC values (14-20%) measured with a strain gauge in a prone position (Plamondon et al., 2004). Corin et al. compared several ways to test muscle fatigue (Corin et al., 2005) but according to our knowledge, no study has really investigated the clinimetric properties of such assessments. The isokinetic dynamometers enable to assess fatigue resistance of trunk extensors by requiring more than 15 repetitions at maximal intensity; the torque decrease (fatigue index) throughout the test is generally considered as a good indicator of fatigue resistance (Cale-Benzoor et al., 1992; Genty & Schmidt, 2001; McGregor et al., 2004). The high cardiovascular stress induced by such tests, which can be an important factor-limiting performance (Rantanen et al., 1995), might explain why they have been poorly investigated; furthermore, dizziness has been reported after such exercise (Peel & Alland, 1990) and a huge increase in heart rate (HR), which could reach 90% of maximal theoretical HR at the end of 20 repetitions, was reported (Rantanen et al., 1995). Therefore, caution is needed when testing

Nowadays, for fatigue assessment, the surface electromyography (S-EMG) technique is often used and coupled to the endurance tests previously described, which are most of the time limited in time; thus S-EMG is used as an alternative to maximum effort tests to assess

Maximum effort tests have generally pointed out decreased trunk muscle performance in patients with CLBP. Most authors having observed such changes suggested that they could result from physical deconditioning and the associated alterations in the size (decrease in cross-sectional surface area of spinal muscles), density (fatty infiltration) and structure (fibers size reduction) of the trunk muscles (Hultman et al., 1993; Gibbons et al., 1997b; Raty et al., 1999; Danneels et al., 2000; Barker et al., 2004; Demoulin et al., 2007). However, several more recent papers consider that there is minimal research evidence that patients with CLBP really suffer from disuse, physical deconditioning (Smeets & Wittink, 2007; Verbunt et al., 2010) and morphologic alterations (Crossman et al., 2004; Smeets & Wittink, 2007; Verbunt

The decrease in performance found in patients could partly result from of a lack of validity of such assessments which require maximal collaboration of subjects to produce a maximal effort in terms of intensity or duration (Newton & Waddell, 1993). Therefore, results can be influenced by several individual confounding factors such as motivation, pain tolerance, competitiveness (Mannion & Dolan, 1994); furthermore pain on exertion, anticipation or fear of pain and reflex inhibition of motor activation can be additional factors resulting in

patients with suspected heart problems (Rantanen et al., 1995).

trunk muscle performance (see below).

**2.3 Interpretation of results** 

et al., 2010).

**2.2.3 Muscle fatigue tests** 

#### **2.2.3 Muscle fatigue tests**

150 Low Back Pain

Muscle static endurance can be assessed with several dynamometers by measuring the time during which a subject is able to maintain a specific torque level corresponding at a preset relative percentage (often 40-60%) of the MVC previously determined (Jorgensen, 1997; Kankaanpaa et al., 1998b; Udermann et al., 2003; Demoulin et al., 2009). A visual feedback system, displaying the torque in real time, is generally positioned in front of the subject in order to keep a constant torque. This test performed in standing position, used for more than 25 years (Nicolaisen & Jorgensen, 1985), is sometimes considered to be more appropriate than the Sorensen test because it is less sensitive to heterogeneous physiques (Jorgensen, 1997; Kankaanpaa et al., 1998a; da Silva et al., 2005). Demoulin et al. compared a seated endurance test performed on a specific dynamometer (David) (Fig. 7a) to the Sorensen test in healthy subjects; they reported limited pain in the back during performance of both tests and similar subjective level of exertion and cardiovascular stress (Demoulin et al., 2009). As for the MVC test performed on this device, this seated endurance test induces hip extensors activation in spite of the hip stabilization system (Kankaanpaa et al., 1998b); unfortunately, this endurance test has a low test-retest reliability as well in healthy subjects as in patients with CLBP (Demoulin, 2008). Static endurance of trunk extensors have also been measured while the subject performs a lifting test (Mannion et al., 1997a; da Silva et al., 2005); however, such tests produce less fatigue in the back muscles than the Sorensen or the

Muscle dynamic endurance can be assessed with dynamometers by measuring the maximal number of repetitions performed with a specific load, with a preset speed and range of motion. The literature reports only few studies using such tests: on the David device (Fig. 7b), the load used corresponded to [0.4 x height (meter)] x [0.6 x Weight (kg)] x 0.82 (Kankaanpaa et al., 1997). This test seems to be less reproducible and well tolerated than the MVC strength and static endurance tests (Demoulin, 2008). Similar tests have been described with the Isostation

B-200 (Morlock et al., 1997) and the MedX (Udermann et al., 2003).

a) b)

Fig. 7. a) Static endurance test, b) Dynamic endurance test

**2.2.2 Endurance tests 2.2.2.1 Static endurance** 

pulling tests (da Silva et al., 2005).

**2.2.2.2 Dynamic endurance** 

Muscle fatigue can be defined as "an exercise-induced reduction in the ability of muscle to produce force or power whether or not the task can be sustained" (Enoka & Duchateau, 2008). Fatigue can be calculated by comparing the maximal strength (MVCs) prior and after an exhaustion task; in the study of Al-Obaidi et al., the task consisted in performing as many extension movements as possible against a predefined individual resistance (corresponding at 50% of the pre-MVC) (Al-Obaidi et al., 2003). Plamondon et al. submitted healthy students to an intermittent prone back extension exercise (100 dynamic repetitions) and reported fatigue of trunk extensors according to the decrease of MVC values (14-20%) measured with a strain gauge in a prone position (Plamondon et al., 2004). Corin et al. compared several ways to test muscle fatigue (Corin et al., 2005) but according to our knowledge, no study has really investigated the clinimetric properties of such assessments.

The isokinetic dynamometers enable to assess fatigue resistance of trunk extensors by requiring more than 15 repetitions at maximal intensity; the torque decrease (fatigue index) throughout the test is generally considered as a good indicator of fatigue resistance (Cale-Benzoor et al., 1992; Genty & Schmidt, 2001; McGregor et al., 2004). The high cardiovascular stress induced by such tests, which can be an important factor-limiting performance (Rantanen et al., 1995), might explain why they have been poorly investigated; furthermore, dizziness has been reported after such exercise (Peel & Alland, 1990) and a huge increase in heart rate (HR), which could reach 90% of maximal theoretical HR at the end of 20 repetitions, was reported (Rantanen et al., 1995). Therefore, caution is needed when testing patients with suspected heart problems (Rantanen et al., 1995).

Nowadays, for fatigue assessment, the surface electromyography (S-EMG) technique is often used and coupled to the endurance tests previously described, which are most of the time limited in time; thus S-EMG is used as an alternative to maximum effort tests to assess trunk muscle performance (see below).

#### **2.3 Interpretation of results**

Maximum effort tests have generally pointed out decreased trunk muscle performance in patients with CLBP. Most authors having observed such changes suggested that they could result from physical deconditioning and the associated alterations in the size (decrease in cross-sectional surface area of spinal muscles), density (fatty infiltration) and structure (fibers size reduction) of the trunk muscles (Hultman et al., 1993; Gibbons et al., 1997b; Raty et al., 1999; Danneels et al., 2000; Barker et al., 2004; Demoulin et al., 2007). However, several more recent papers consider that there is minimal research evidence that patients with CLBP really suffer from disuse, physical deconditioning (Smeets & Wittink, 2007; Verbunt et al., 2010) and morphologic alterations (Crossman et al., 2004; Smeets & Wittink, 2007; Verbunt et al., 2010).

The decrease in performance found in patients could partly result from of a lack of validity of such assessments which require maximal collaboration of subjects to produce a maximal effort in terms of intensity or duration (Newton & Waddell, 1993). Therefore, results can be influenced by several individual confounding factors such as motivation, pain tolerance, competitiveness (Mannion & Dolan, 1994); furthermore pain on exertion, anticipation or fear of pain and reflex inhibition of motor activation can be additional factors resulting in

Muscular Performance Assessment of Trunk Extensors: A Critical Appraisal of the Literature 153

clinical data (Taimela et al., 1998). However, according to our knowledge, no other study

Mannion et al. conducted a very interesting study to determine whether the twitch superimposition technique could be used to predict maximum force (isometric lifting test) of the spinal muscles from submaximal efforts (Mannion et al., 1997b). Although they reported an excellent curvilinear relationship between twitch force and submaximal force being sustained, they observed that the predicted MVC (extrapolated from the relationship) underestimated the true strength by about 18%. Such difference might result partly from the difficulty in stimulating the spinal muscle mass as a whole. The authors concluded that another testing apparatus and/or subject's posture might result in a more accurate prediction of maximal force (Mannion et al., 1997b). However, no other studies have used the twitch superimposition technique to predict back muscle maximal force since then.

**Surface electromyography** (S-EMG) technique is sometimes considered as the best tool to assess objectively trunk extensors muscle function because it enables to investigate and compare simultaneously and specifically several back muscles. Furthermore, this technique can be used during a submaximal and time-limited effort in order to limit the influence of individual factors (motivation, fears, etc.). Therefore S-EMG coupled to the endurance field (Sorensen, etc.) and dynamometric (static or dynamic) tests previously described have been frequently used in the literature (Mannion et al., 1997a; Elfving et al., 2000; Koumantakis et al., 2001, Ng et al., 1997; Kankaanpaa et al., 2005; Demoulin et al., 2007). Some devices such as the Back Analysis System (NeuroMuscular Research Center, Boston University, Boston, USA) were even developed to standardize assessments of back muscle dysfunction (i.e. repeated isometric extensions at a given percentage of the MVC associated to S-EMG monitoring) (De Luca, 1993; Roy et al., 1995). The EMG power spectrum has been widely used to calculate the median frequency (MF), mean power frequency (MPF), as well as their rates of decline during prolonged exercise in order to reflect muscle fatigue (Vollestad, 1997). Several studies observed that EMG fatigue parameters recorded after a prespecified period (often 45-60 seconds) of a fatiguing task were significantly correlated to the parameters monitored at the end of the endurance test (van Dieen et al., 1998; Suter & Lindsay, 2001) as well as to the maximal holding time (Kankaanpaa et al., 1997; Mannion et al., 1997a; van Dieen et al., 1998; Dedering et al., 1999). Furthermore, EMG fatigue parameters could be a better predictor of low back disorder than the maximal holding time

Though submaximal tests coupled to S-EMG have become very popular, the validity of the EMG submaximal endurance tests performed at a given percentage of the MVC can be questioned. Indeed, the intensity of effort during such tests depends on the factors (motivation, pain, fears, etc.) influencing the MVC test previously performed; the absence of difference in EMG parameters between healthy and patients with CLBP and the smaller decrease in power frequency (reflecting lower fatigue) found in the latter group in some studies could be explained by the underestimation of the patients MVC resulting in a lower load level (Elfving et al., 2003; Lariviere et al., 2003a; Kramer et al., 2005). In order to avoid such a bias and to limit the influence of the anthropometric variables, Larivière et al. recently proposed a promising assessment based on S-EMG monitoring during intermittent submaximal static contractions (6,5 seconds contraction / 1,5 second rest) performed in a non-commercial trunk dynamometer at a specific intensity (90 N.m) during 5 to 10 minutes

has used this test.

(Mannion et al., 1997a).

inability or unwillingness to produce a truly maximal effort in patients with LBP (Menard et al., 1994; Vlaeyen et al., 1995; Crombez et al., 1996; Keller et al., 1999; Rashiq et al., 2003; Rainville et al., 2004; Al-Obaidi et al., 2005; Ropponen et al., 2005; Verbunt et al., 2005; Thomas et al., 2008; Huijnen et al., 2010). These individual factors might explain the absence or low correlations found in some studies between morphologic variables and performance (Parkkola et al., 1993; Gibbons et al., 1997a). They might also explain the significant learning effect observed in some patients, reflected by performance higher at the second trial than at the first one (Grabiner et al., 1990; Newton & Waddell, 1993; Lariviere et al., 2003b; Gruther et al., 2009). Such learning effect might explain partly the increase in trunk extensor performance sometimes observed after only a few training sessions (Mannion et al., 2001; Demoulin et al., 2010). Therefore, such increase in performance should always be interpreted with caution.

Therefore, although several studies reported no or low correlations between pain or disability and trunk extensor performance (Newton et al., 1993; Gronblad et al., 1997; Bayramoglu et al., 2001; da Silva et al., 2005), these maximum effort tests could also be considered as psychophysical test, reflecting in some cases more the fears and pain tolerance than the muscle function. Consequently, the relevance of using such tests in very painful patients is doubtful. Besides, a period of familiarization with the test appears absolutely necessary in order to eliminate the learning effect and the risk to underestimate real performance.

The technique of twitch interpolation seems a research method able to identify the role of non-physiological factors during strength testing (Verbunt et al., 2003). It is based on the registration of a twitch contraction elicited by a supramaximal electrical stimulus delivered to the muscle or nerve during a MVC. The force increment in response to this stimulus reflects the muscle force reserve or the difference between the maximum force that can be generated by the muscle and the maximum voluntary contraction force, in which nonphysiological factors play a role (Verbunt et al., 2003). This technique was used to compare healthy subjects with patients with LBP regarding knee extensor inhibition in a few studies (Suter & Lindsay, 2001; Verbunt et al., 2005); a lower central activation ratio was reported in patients experiencing increased psychological distress and with higher pain intensity (Verbunt et al., 2005).

#### **3. Alternative to maximum effort tests to assess trunk muscle performance**

A few studies examined whether trunk extensor strength could be predicted by anthropometric variables (Mannion et al., 1999a; Wang et al., 2005); indeed, such a prediction is of particular interest in patients who cannot perform maximal tests in order to determine appropriate loads for rehabilitation training (Mannion et al., 1999a). If these variables seem to influence muscle performance, their ability to predict accurately muscle capacity remains limited (Lariviere et al., 2003b).

Taimela et al. developed a submaximal dynamic back extension endurance test utilising subjective perception of low back fatigue (Taimela et al., 1998). They reported that the perceived fatigue (assessed by means of a Borg scale every 15 seconds) increased faster in patients with LBP disorders than in healthy subjects and suggested that this test might be a low-risk, low-cost evaluation method for assessing LBP patient when combined with other

inability or unwillingness to produce a truly maximal effort in patients with LBP (Menard et al., 1994; Vlaeyen et al., 1995; Crombez et al., 1996; Keller et al., 1999; Rashiq et al., 2003; Rainville et al., 2004; Al-Obaidi et al., 2005; Ropponen et al., 2005; Verbunt et al., 2005; Thomas et al., 2008; Huijnen et al., 2010). These individual factors might explain the absence or low correlations found in some studies between morphologic variables and performance (Parkkola et al., 1993; Gibbons et al., 1997a). They might also explain the significant learning effect observed in some patients, reflected by performance higher at the second trial than at the first one (Grabiner et al., 1990; Newton & Waddell, 1993; Lariviere et al., 2003b; Gruther et al., 2009). Such learning effect might explain partly the increase in trunk extensor performance sometimes observed after only a few training sessions (Mannion et al., 2001; Demoulin et al., 2010). Therefore, such increase in performance should always be

Therefore, although several studies reported no or low correlations between pain or disability and trunk extensor performance (Newton et al., 1993; Gronblad et al., 1997; Bayramoglu et al., 2001; da Silva et al., 2005), these maximum effort tests could also be considered as psychophysical test, reflecting in some cases more the fears and pain tolerance than the muscle function. Consequently, the relevance of using such tests in very painful patients is doubtful. Besides, a period of familiarization with the test appears absolutely necessary in order to eliminate the learning effect and the risk to underestimate real

The technique of twitch interpolation seems a research method able to identify the role of non-physiological factors during strength testing (Verbunt et al., 2003). It is based on the registration of a twitch contraction elicited by a supramaximal electrical stimulus delivered to the muscle or nerve during a MVC. The force increment in response to this stimulus reflects the muscle force reserve or the difference between the maximum force that can be generated by the muscle and the maximum voluntary contraction force, in which nonphysiological factors play a role (Verbunt et al., 2003). This technique was used to compare healthy subjects with patients with LBP regarding knee extensor inhibition in a few studies (Suter & Lindsay, 2001; Verbunt et al., 2005); a lower central activation ratio was reported in patients experiencing increased psychological distress and with higher pain

**3. Alternative to maximum effort tests to assess trunk muscle performance**  A few studies examined whether trunk extensor strength could be predicted by anthropometric variables (Mannion et al., 1999a; Wang et al., 2005); indeed, such a prediction is of particular interest in patients who cannot perform maximal tests in order to determine appropriate loads for rehabilitation training (Mannion et al., 1999a). If these variables seem to influence muscle performance, their ability to predict accurately muscle

Taimela et al. developed a submaximal dynamic back extension endurance test utilising subjective perception of low back fatigue (Taimela et al., 1998). They reported that the perceived fatigue (assessed by means of a Borg scale every 15 seconds) increased faster in patients with LBP disorders than in healthy subjects and suggested that this test might be a low-risk, low-cost evaluation method for assessing LBP patient when combined with other

interpreted with caution.

intensity (Verbunt et al., 2005).

capacity remains limited (Lariviere et al., 2003b).

performance.

clinical data (Taimela et al., 1998). However, according to our knowledge, no other study has used this test.

Mannion et al. conducted a very interesting study to determine whether the twitch superimposition technique could be used to predict maximum force (isometric lifting test) of the spinal muscles from submaximal efforts (Mannion et al., 1997b). Although they reported an excellent curvilinear relationship between twitch force and submaximal force being sustained, they observed that the predicted MVC (extrapolated from the relationship) underestimated the true strength by about 18%. Such difference might result partly from the difficulty in stimulating the spinal muscle mass as a whole. The authors concluded that another testing apparatus and/or subject's posture might result in a more accurate prediction of maximal force (Mannion et al., 1997b). However, no other studies have used the twitch superimposition technique to predict back muscle maximal force since then.

**Surface electromyography** (S-EMG) technique is sometimes considered as the best tool to assess objectively trunk extensors muscle function because it enables to investigate and compare simultaneously and specifically several back muscles. Furthermore, this technique can be used during a submaximal and time-limited effort in order to limit the influence of individual factors (motivation, fears, etc.). Therefore S-EMG coupled to the endurance field (Sorensen, etc.) and dynamometric (static or dynamic) tests previously described have been frequently used in the literature (Mannion et al., 1997a; Elfving et al., 2000; Koumantakis et al., 2001, Ng et al., 1997; Kankaanpaa et al., 2005; Demoulin et al., 2007). Some devices such as the Back Analysis System (NeuroMuscular Research Center, Boston University, Boston, USA) were even developed to standardize assessments of back muscle dysfunction (i.e. repeated isometric extensions at a given percentage of the MVC associated to S-EMG monitoring) (De Luca, 1993; Roy et al., 1995). The EMG power spectrum has been widely used to calculate the median frequency (MF), mean power frequency (MPF), as well as their rates of decline during prolonged exercise in order to reflect muscle fatigue (Vollestad, 1997). Several studies observed that EMG fatigue parameters recorded after a prespecified period (often 45-60 seconds) of a fatiguing task were significantly correlated to the parameters monitored at the end of the endurance test (van Dieen et al., 1998; Suter & Lindsay, 2001) as well as to the maximal holding time (Kankaanpaa et al., 1997; Mannion et al., 1997a; van Dieen et al., 1998; Dedering et al., 1999). Furthermore, EMG fatigue parameters could be a better predictor of low back disorder than the maximal holding time (Mannion et al., 1997a).

Though submaximal tests coupled to S-EMG have become very popular, the validity of the EMG submaximal endurance tests performed at a given percentage of the MVC can be questioned. Indeed, the intensity of effort during such tests depends on the factors (motivation, pain, fears, etc.) influencing the MVC test previously performed; the absence of difference in EMG parameters between healthy and patients with CLBP and the smaller decrease in power frequency (reflecting lower fatigue) found in the latter group in some studies could be explained by the underestimation of the patients MVC resulting in a lower load level (Elfving et al., 2003; Lariviere et al., 2003a; Kramer et al., 2005). In order to avoid such a bias and to limit the influence of the anthropometric variables, Larivière et al. recently proposed a promising assessment based on S-EMG monitoring during intermittent submaximal static contractions (6,5 seconds contraction / 1,5 second rest) performed in a non-commercial trunk dynamometer at a specific intensity (90 N.m) during 5 to 10 minutes

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(Lariviere et al., 2008a; Lariviere et al., 2009). Their results based on healthy subjects suggest that the EMG indices used in the study could predict absolute endurance as well as strength with the use of a single intermittent and time-limited endurance test (Lariviere et al., 2008b).

Although S-EMG technique appears attractive, it presents some drawbacks. Indeed, EMG results are influenced by many factors including the type, size, and location of the electrodes, the impedance of the source and amplifier, the location of the motor points, the type of contraction, the temperature of the muscle and skin, the force produced by the contraction, the fiber composition, the blood flow and the fat layer thickness (De Luca, 1993). Whereas intra-session reproducibility of EMG parameters seems generally satisfactory (Ng & Richardson, 1996), inter-session and inter-operator reproducibility remains controversial (Peach et al., 1998; Elfving et al., 1999; Danneels et al., 2001). Furthermore, S-EMG might not reliably isolate the activity of the different back muscles (Stokes et al., 2003) and the interpretation of EMG measurements at an individual level remains impossible at the moment because of the considerable inter-individual variability (Elfving et al., 2000; Arnall et al., 2002), thereby limiting its diagnostic usefulness (Pullman et al., 2000; Lariviere et al., 2002). Finally, the absence of standardized EMG protocols prevents from performing several comparative studies.

#### **4. Conclusions**

As shown in this review, several methods have been used to assess trunk extensor muscle performance. Unfortunately there is not yet a consensus regarding the optimal test to be used and the present literature review does not enable such a test to be determined. Further studies about the clinimetric properties of the maximal effort tests as well as comparison studies between the various existing tests and tools are needed. Anyway, when using such tests, several methodological cautions are necessary in clinical practice (e.g. a familiarization period to the device and to the test, several trials authorized, etc.) in order to avoid a learning effect; furthermore, results interpretation should always be careful, especially in painful or fearful subjects considering the risk of underestimating the true muscle performance. Additional effort to develop a submaximal test remains essential. Although the S-EMG technique appears to be a key investigation tool for research because individual factors do not influence the outcomes, further investigations are necessary to make the measurement interpretation possible at an individual level.

#### **5. Acknowledgements**

The authors thank Prof M. Szpalsky and F. Balagué for providing some pictures as well as A. Depaifve and S. Wolfs for their help, cooperation and valuable assistance.

#### **6. References**

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Al-Obaidi, S.; Al-Zoabi, B.; Chowdhury, R. & Al-Shuwai, N. (2003). Fatigue susceptibility of the lumbar extensor muscles among smokers. *Physiotherapy,* Vol.89, No.4, pp. 238- 248.

(Lariviere et al., 2008a; Lariviere et al., 2009). Their results based on healthy subjects suggest that the EMG indices used in the study could predict absolute endurance as well as strength with the use of a single intermittent and time-limited endurance test (Lariviere et al., 2008b). Although S-EMG technique appears attractive, it presents some drawbacks. Indeed, EMG results are influenced by many factors including the type, size, and location of the electrodes, the impedance of the source and amplifier, the location of the motor points, the type of contraction, the temperature of the muscle and skin, the force produced by the contraction, the fiber composition, the blood flow and the fat layer thickness (De Luca, 1993). Whereas intra-session reproducibility of EMG parameters seems generally satisfactory (Ng & Richardson, 1996), inter-session and inter-operator reproducibility remains controversial (Peach et al., 1998; Elfving et al., 1999; Danneels et al., 2001). Furthermore, S-EMG might not reliably isolate the activity of the different back muscles (Stokes et al., 2003) and the interpretation of EMG measurements at an individual level remains impossible at the moment because of the considerable inter-individual variability (Elfving et al., 2000; Arnall et al., 2002), thereby limiting its diagnostic usefulness (Pullman et al., 2000; Lariviere et al., 2002). Finally, the absence of standardized EMG protocols

As shown in this review, several methods have been used to assess trunk extensor muscle performance. Unfortunately there is not yet a consensus regarding the optimal test to be used and the present literature review does not enable such a test to be determined. Further studies about the clinimetric properties of the maximal effort tests as well as comparison studies between the various existing tests and tools are needed. Anyway, when using such tests, several methodological cautions are necessary in clinical practice (e.g. a familiarization period to the device and to the test, several trials authorized, etc.) in order to avoid a learning effect; furthermore, results interpretation should always be careful, especially in painful or fearful subjects considering the risk of underestimating the true muscle performance. Additional effort to develop a submaximal test remains essential. Although the S-EMG technique appears to be a key investigation tool for research because individual factors do not influence the outcomes, further investigations are necessary to make the measurement

The authors thank Prof M. Szpalsky and F. Balagué for providing some pictures as well as

Adams, M.A.; Mannion, A.F. & Dolan, P. (1999). Personal risk factors for first-time low back

Al-Obaidi, S.; Al-Zoabi, B.; Chowdhury, R. & Al-Shuwai, N. (2003). Fatigue susceptibility of

the lumbar extensor muscles among smokers. *Physiotherapy,* Vol.89, No.4, pp. 238-

A. Depaifve and S. Wolfs for their help, cooperation and valuable assistance.

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strength in 15-year-old schoolchildren with and without low-back pain. *Spine,* 

prospective three-year follow-up study of subjects with and without low back pain.

Effects of pelvic stabilization on lumbar muscle activity during dynamic exercise.


**Section 2** 

**Treatment Approach** 

