**5. Effort evaluation**

The level of effort involved in the development of work tasks in a particular job is a risk factor for musculoskeletal pathologies. In this sense, different instrumental techniques and electronic measurement systems are used to evaluate the level of effort, such as electromyography (**Figure 21**), which allows to characterize the intensity of muscle intervention of a specific muscle and detect muscle fatigue if it occurs. Force sensors such as force plates allow to measure the reaction force with the environment, and contact pressure sensors allow to measure the pressure that the surgeon experiences when holding and manipulating laparoscopic instruments, which also constitutes a risk factor. In the studies carried out by the BioẼrgon Group, surface electromyography (EMG) has been used as an instrumental technique to analyze the relationship of the position adopted by the surgeons.

## **5.1 Surface electromyography**

Electromyographic data were recorded with the surface electrode and were carried out to establish upper trapezius and middle deltoid intervention as neckshoulder area stabilizers. Thirteen surgeons (four woman and nine men), with different experience levels, performed a surgery simulation of 60 minutes duration at the Jesús Usón Minimally Invasive Surgery Centre, as mentioned in Section 4. The analysis of the electromyographic data in the frequency domain made it possible to detect median frequency (fmedian) of the appearance of local muscular fatigue (LMF), which is one of the risk factors that cause discomfort and musculoskeletal disorders. Surgery time was divided into 60 intervals with a duration of 1 minute each. In each interval, an EMG record was made, meaning that a period of 1 minute passed between one record and the next. Results show that LFM appears in 62% of analyzed surgeons in part of the analyzed muscles (**Table 1**).

Therefore, it would be advisable to pay special attention to work-rest guidelines, especially for female surgeons. Taking into account the results of the kinematic analysis, it can be stated that the combination of abduction with the elevation of the arms is associated with a high activity of the deltoid and results in the appearance of muscle fatigue that was detected. The appearance of local muscle fatigue has also been confirmed in another study conducted in collaboration between BioẼrgon Group and CCMIJU, where the same methodology as described above was used. Eight experienced surgeons in laparoscopy and LESS (>100 laparoscopic

**25**

*\*p* ≤ *0.05. \*\*p* ≤ *0.01. \*\*\*p* ≤ *0.001.*

**Table 1.**

*Advanced Ergonomics in Laparoscopic Surgery DOI: http://dx.doi.org/10.5772/intechopen.84233*

procedures and >20 single incision procedures) performed a dissection of the serosa layer of a porcine stomach, attempting to separate the serosa layer from the muscular layers. The single port approach led to significantly greater muscle activity in the paraspinal muscles of the right middle cervical portion and the upper right trapezius than the conventional laparoscopic approach. In both approaches, surgeons showed muscle fatigue in at least one of the analyzed muscles. During dissection using a conventional laparoscopic approach, seven of the surgeons reported muscle fatigue in the upper left trapezius. In the case of the single port approach, seven of the surgeons showed muscle fatigue in the right middle trapezius and they showed increased muscle activity in the paraspinal muscles of the right middle cervical portion and in the right upper trapezius. In both procedures, significant EMG spectral shifts toward lower frequencies were seen in at least one muscle in all surgeons, except for one surgeon during LESS. Significant differences were found for the right upper trapezius and mid-cervical paraspinal muscles (F[1, 7] > 6.65 and p < 0.05). With the introduction of the instruments with new features and design [35] in the market, comparative studies are carried out with the aim of verifying their functionality and usability. One of the performed studies involved three experienced laparoscopic surgeons carrying out three intracorporeal cutting tasks on a box trainer using a conventional laparoscopic Maryland dissector and a pair of scissors as well as their equivalent r2 DRIVE instruments. Surgeon ergonomics were evaluated through analysis of the surface electromyography of trapezius, deltoid, and paravertebral muscles. Results show that muscle activity of the surgeons was significantly higher for the left deltoid muscle and bilaterally for the muscle trape-

*Results of LMF observed cases. RT, right trapezius; LT, left trapezius; RD, right deltoid; LD, left deltoid.*

*p***-Value T r R2**

01 RT fMEAN 40–60 0.0023\*\* −4.21 −0.81 66.32% 02 RT fMEAN 20–40 0.0023\*\* −3.77 −0.72 52.20% 02 RT fMEAN 40–60 0.0085\*\* −3.19 −0.69 48.00% 02 LT fMEAN 20–40 0.0038\*\* −3.51 −0.69 48.66% 03 LT fMEAN 0–20 0.0000\*\*\* −5.38 −0.79 63.00% 03 LD fMEAN 20–40 0.0025\*\* −3.54 −0.65 42.46% 04 RD fMEAN 20–40 0.0302\* −2.36 −0.50 24.75% 04 RT fMEAN 40–60 0.0106\* −3.45 −0.79 63.01% 06 LD fMEAN 20–40 0.0000\*\*\* −5.95 −0.85 73.13% 07 RD fMEAN 40–60 0.0095\*\* −3.20 −0.71 50.60% 08 LT fMEAN 20–40 0.005\*\* −3.49 −0.72 52.65% 08 LD fMEAN 20–40 0.0092\*\* −3.15 −0.69 47.45% 09 LD fMEAN 20–40 0.0375\* −2.56 −0.69 48.38% 11 TD fMEAN 0–20 0.0358\* −3.63 −0.90 81.50%

zius when the novel instruments are used (**Figure 22**).

Finally, twelve laparoscopic partial nephrectomies of the caudal pole in an experimental porcine model were performed by two experienced laparoscopic surgeons, using conventional laparoscopic instruments and laparoscopic instruments with

**Figure 21.** *EMG signal. Blue: rectified signal and red: RMSEMG.*



#### **Table 1.**

*Recent Advances in Laparoscopic Surgery*

**5.1 Surface electromyography**

The level of effort involved in the development of work tasks in a particular job is a risk factor for musculoskeletal pathologies. In this sense, different instrumental techniques and electronic measurement systems are used to evaluate the level of effort, such as electromyography (**Figure 21**), which allows to characterize the intensity of muscle intervention of a specific muscle and detect muscle fatigue if it occurs. Force sensors such as force plates allow to measure the reaction force with the environment, and contact pressure sensors allow to measure the pressure that the surgeon experiences when holding and manipulating laparoscopic instruments, which also constitutes a risk factor. In the studies carried out by the BioẼrgon Group, surface electromyography (EMG) has been used as an instrumental tech-

nique to analyze the relationship of the position adopted by the surgeons.

analyzed surgeons in part of the analyzed muscles (**Table 1**).

Electromyographic data were recorded with the surface electrode and were carried out to establish upper trapezius and middle deltoid intervention as neckshoulder area stabilizers. Thirteen surgeons (four woman and nine men), with different experience levels, performed a surgery simulation of 60 minutes duration at the Jesús Usón Minimally Invasive Surgery Centre, as mentioned in Section 4. The analysis of the electromyographic data in the frequency domain made it possible to detect median frequency (fmedian) of the appearance of local muscular fatigue (LMF), which is one of the risk factors that cause discomfort and musculoskeletal disorders. Surgery time was divided into 60 intervals with a duration of 1 minute each. In each interval, an EMG record was made, meaning that a period of 1 minute passed between one record and the next. Results show that LFM appears in 62% of

Therefore, it would be advisable to pay special attention to work-rest guidelines,

especially for female surgeons. Taking into account the results of the kinematic analysis, it can be stated that the combination of abduction with the elevation of the arms is associated with a high activity of the deltoid and results in the appearance of muscle fatigue that was detected. The appearance of local muscle fatigue has also been confirmed in another study conducted in collaboration between BioẼrgon Group and CCMIJU, where the same methodology as described above was used. Eight experienced surgeons in laparoscopy and LESS (>100 laparoscopic

**5. Effort evaluation**

**24**

**Figure 21.**

*EMG signal. Blue: rectified signal and red: RMSEMG.*

*Results of LMF observed cases. RT, right trapezius; LT, left trapezius; RD, right deltoid; LD, left deltoid.*

procedures and >20 single incision procedures) performed a dissection of the serosa layer of a porcine stomach, attempting to separate the serosa layer from the muscular layers. The single port approach led to significantly greater muscle activity in the paraspinal muscles of the right middle cervical portion and the upper right trapezius than the conventional laparoscopic approach. In both approaches, surgeons showed muscle fatigue in at least one of the analyzed muscles. During dissection using a conventional laparoscopic approach, seven of the surgeons reported muscle fatigue in the upper left trapezius. In the case of the single port approach, seven of the surgeons showed muscle fatigue in the right middle trapezius and they showed increased muscle activity in the paraspinal muscles of the right middle cervical portion and in the right upper trapezius. In both procedures, significant EMG spectral shifts toward lower frequencies were seen in at least one muscle in all surgeons, except for one surgeon during LESS. Significant differences were found for the right upper trapezius and mid-cervical paraspinal muscles (F[1, 7] > 6.65 and p < 0.05). With the introduction of the instruments with new features and design [35] in the market, comparative studies are carried out with the aim of verifying their functionality and usability. One of the performed studies involved three experienced laparoscopic surgeons carrying out three intracorporeal cutting tasks on a box trainer using a conventional laparoscopic Maryland dissector and a pair of scissors as well as their equivalent r2 DRIVE instruments. Surgeon ergonomics were evaluated through analysis of the surface electromyography of trapezius, deltoid, and paravertebral muscles. Results show that muscle activity of the surgeons was significantly higher for the left deltoid muscle and bilaterally for the muscle trapezius when the novel instruments are used (**Figure 22**).

Finally, twelve laparoscopic partial nephrectomies of the caudal pole in an experimental porcine model were performed by two experienced laparoscopic surgeons, using conventional laparoscopic instruments and laparoscopic instruments with

#### **Figure 22.**

*Muscle activity (RMSEMG) of the paravertebral, deltoid, and trapezius muscles during the use of the conventional and r2 DRIVE laparoscopic instruments.*

articulated handle with rings. Results confirmed that although the novel instruments have a new design that incorporates ergonomic criteria, they produced localized muscle fatigue in the left deltoid and bilaterally in the lower trapezius muscles when using the dissector. Even though the surgeons did not notice differences in use and physical workload, the new instruments led to localized muscle fatigue.

#### **5.2 Localized contact pressure**

Finally, the last relevant risk factor in the surgical context is **localized contact pressure** (**Figure 23**) that can cause nerve injuries and injuries of the tissue below the skin, especially when it is carried out in a repeated way or when it is maintained for a long time, situations that typically occur during laparoscopic surgery. Sensors and electronic systems are used to record the level and distribution of pressure during the manipulation of laparoscopic instruments (**Figure 23**). This technology allows to evaluate if the pressure levels are harmful for the surgeon and to draw conclusions on the most suitable design of the contact surfaces of the laparoscopic material [36].

Two studies performed in collaboration between CCMIJU and BioẼrgon Group surgeons carried out a urethrovesical anastomosis on a porcine model using a novel handheld robotic laparoscopic instrument and a conventional axial handheld laparoscopic needle holder (two experienced surgeons >100 laparoscopic procedures in the first study and five experienced surgeons in the second one). On the one hand, results show that the pressure exerted by the thumb is notably higher during the use of the robotic instrument. This is due to the interaction with the controls installed on the handle of the instrument. The pressures registered by the index and middle finger as well as the palm of the hand are very similar when using both types of laparoscopic instruments, except for the thumb finger [36]. On the other hand, results showed that the force exerted by the distal phalange of the index finger was significantly higher on the conventional handle as compared to the force exerted on the handle of the robotic instrument. The palm of the hand was the area that received the highest pressure in both instruments, but for longer periods when using the robotic instrument. However, further studies are required to analyze the pressure applied on these laparoscopic instruments by other parts of the hands, such as the intermediate phalanges of the thumb, index, and middle fingers [37].

**27**

uncontrolled manifold hypothesis model.

**6. Conclusion**

**Figure 23.**

In this chapter, results of the research work carried out by the collaboration between the BioẼrgon Research Group and the Jesús Usón Minimally Invasive

*Contact pressure measurement, generated during the use of laparoscopic instrumental.*

Surgery Centre (CCMIJU) during the last 15 years have been presented. This research was performed based on the methodology of ergonomics, using the instrumental techniques of the Biomechanics of Human Movement to analyze the presence of risk factors of musculoskeletal pathologies in the multiple tasks of laparoscopic surgery and to establish ergonomic criteria that allow to improve the working conditions of surgeons, as well as the design of the laparoscopic material. Results of the research are useful for organizational and ergonomic decision-making, aimed at the introduction of an ergonomic conception of laparoscopic surgery processes for the improvement of occupational health and quality of life of the surgeons. Factors and levels of risk of suffering musculoskeletal injuries in the neck and shoulder associated with posture and muscular activity have been determined, which can be used for the prevention of musculoskeletal pathologies. In addition, the knowledge what was gathered from the real environment of the operating theater can be useful for training of surgeons in laparoscopic surgery on adaptation of the posture during the intervention. Finally, it is relevant to highlight the whole research process conducted for more than a decade, starting from the initial epidemiological study and evolving with the use of biomechanics methodology up to the analysis of neuromuscular control strategies using the

*Advanced Ergonomics in Laparoscopic Surgery DOI: http://dx.doi.org/10.5772/intechopen.84233* *Advanced Ergonomics in Laparoscopic Surgery DOI: http://dx.doi.org/10.5772/intechopen.84233*

*Recent Advances in Laparoscopic Surgery*

**5.2 Localized contact pressure**

*conventional and r2 DRIVE laparoscopic instruments.*

**Figure 22.**

articulated handle with rings. Results confirmed that although the novel instruments have a new design that incorporates ergonomic criteria, they produced localized muscle fatigue in the left deltoid and bilaterally in the lower trapezius muscles when using the dissector. Even though the surgeons did not notice differences in use and

*Muscle activity (RMSEMG) of the paravertebral, deltoid, and trapezius muscles during the use of the* 

Finally, the last relevant risk factor in the surgical context is **localized contact pressure** (**Figure 23**) that can cause nerve injuries and injuries of the tissue below the skin, especially when it is carried out in a repeated way or when it is maintained for a long time, situations that typically occur during laparoscopic surgery. Sensors and electronic systems are used to record the level and distribution of pressure during the manipulation of laparoscopic instruments (**Figure 23**). This technology allows to evaluate if the pressure levels are harmful for the surgeon and to draw conclusions on the most suitable design of the contact surfaces of the laparoscopic material [36].

Two studies performed in collaboration between CCMIJU and BioẼrgon Group

surgeons carried out a urethrovesical anastomosis on a porcine model using a novel handheld robotic laparoscopic instrument and a conventional axial handheld laparoscopic needle holder (two experienced surgeons >100 laparoscopic procedures in the first study and five experienced surgeons in the second one). On the one hand, results show that the pressure exerted by the thumb is notably higher during the use of the robotic instrument. This is due to the interaction with the controls installed on the handle of the instrument. The pressures registered by the index and middle finger as well as the palm of the hand are very similar when using both types of laparoscopic instruments, except for the thumb finger [36]. On the other hand, results showed that the force exerted by the distal phalange of the index finger was significantly higher on the conventional handle as compared to the force exerted on the handle of the robotic instrument. The palm of the hand was the area that received the highest pressure in both instruments, but for longer periods when using the robotic instrument. However, further studies are required to analyze the pressure applied on these laparoscopic instruments by other parts of the hands, such as the intermediate phalanges of the thumb, index, and middle

physical workload, the new instruments led to localized muscle fatigue.

**26**

fingers [37].

**Figure 23.** *Contact pressure measurement, generated during the use of laparoscopic instrumental.*
