**3. Physical analgesia: mechanisms**

The gate-control theory [5] is widely applied in physical medicine, especially for explanation of physical analgesia, using the principle of the "contra-stimulation" final effect reticence by stimulation of inhibiting systems, or else final effect

stimulation by embarrassment of inhibiting systems [37, 38]. Investigations of J. Gacheva demonstrated that the selective electrostimulation of tactile Аβ-nerve fibers (with high velocity of conduction) provokes a previous stimulation of suppressive neurons, they inhibit the tardily arrived nociceptive stimuli of А-δ and C-fibers (with slower conduction velocity) [37].

At peripheral level, the direct anti-adaptive electrostimulation of receptors probably provokes a hyperpolarization with a decrease of the sensibility of the nociceptors.

A direct low frequency electrical stimulation of the Aδ and C fibers may cause an analgesic effect.

During last years, the development of the physical medicine proved the existence of some reflectory connections in the human body, based on the theory for the metameric structure of the embryo during intra-uterine development. In physical analgesia, we apply the following **groups of reflectory connections** (**Figure 1**).


We consider that physical modalities may provoke an analgesic effect by different pathogenetic mechanisms (**Figure 2**, **Table 2**).

**Figure 1.** *Groups of reflectory connections.*

*Physical Analgesia: Methods, Mechanisms and Algorithms for Post-Operative Pain DOI: http://dx.doi.org/10.5772/intechopen.111590*

#### **Figure 2.**

*Mechanisms of physical analgesia.*


#### **Table 2.**

*Mechanism of physical analgesia and correspondent procedures.*


#### **4. Physical analgesia: systematic mechanisms**

Physical modalities influence at different levels: on the cells and the interstitium, especially on the cellular membrane and on mitochondrial membranes; on the neuron and neuroglia; on systematic level; on psychic condition of the patient (psychoemotional stress of chronic pain).

Low frequency electric currents, Deep oscillation, lasertherapy and active physiotherapy have influence on different mechanisms of cellular alteration, as follows: ischemic, hypoxic, hypo-energetic, oxidative stress.

Some rehabilitation procedures stimulate active hyperemia: electrotherapy, magnetic field, active physiotherapy, hydro- and balneo-therapy, acupuncture.

Other agents reduce passive hyperemia: magnetotherapy, deep oscillation, manual massage, manual lymphatic drainage and lymphopressotherapy, active physiotherapy.

Some procedures influence on the exudative phase of inflammation, reducing exudates: high frequency electric currents, laser, deep oscillation, lymphatic drainage, manual massage, active physiotherapy.

Physical modalities reduce systematic effects of inflammation. Active physiotherapy, manual massage and reflectory techniques reduce toxo-infectious syndrome. Active and passive physiotherapy, lasertherapy and ultra-violet light therapy reduce the asteno-adynamic syndrome. Active physiotherapy and reflectory techniques reduce C-reactive protein, regulate endocrinium, and regulate the balance between sympaticus and parasympathicus.

*Physical Analgesia: Methods, Mechanisms and Algorithms for Post-Operative Pain DOI: http://dx.doi.org/10.5772/intechopen.111590*

Active physiotherapeutic procedures reduce hypoxia (hypoxic, circulatory and tissue hypoxia) and stimulate compensatory mechanisms (respiratory, cardio-vascular and tissular).

Physical modalities ameliorate the function of the central and peripheral nervous system. Low frequency electric currents (iontophoresis, functional electrical stimulations) have influence on neuronal dysfunction. Physiotherapy, transcranial electric and magnetic stimulations stimulate the function of neuronal groups, chains and nets. Active physiotherapy and ergotherapy improve the cerebral function, acting on cerebral ischaemia, the brain oedema and the intracranial hypertension.

#### **5. Physical analgesia: pros and contras**

Physical analgesia is a cheap treatment, accepted positively by patients. Physical procedures have not significant side effects and contra-indications.

The treatment is not difficult for realization, is relatively cheap.

We can combine different rehabilitation procedures. We can combine physical analgesia with other types of analgesia.

We must admit that actually there is a *lack of sufficient evidence* in the area of physical analgesia.

An interdisciplinary team (of medical doctors — specialists in Neurology, Neurosurgery, Rheumatology, Orthopedics and Traumatology, Physical and Rehabilitation Medicine) programs rehabilitation. For practical realization of the procedures, we need a staff of physiotherapists, occupational therapists, nurses, etc.

#### **6. General algorithm for pain management**

Pain management with physical modalities is based on traditions of physical and rehabilitation medicine (PRM). According the definition of the European Union of Medical Specialists—PRM Section [12] this is an independent medical specialty, oriented to the promotion of physical and cognitive functioning, activities, participation and changes in personal factors and environment.

According the World Report on Disability of the World Health Organization and World Bank [39] rehabilitation is a functional treatment, based on a detailed functional assessment. Goals of rehabilitation are functional amelioration and functional recovery [39].

The White Book on Physical and Rehabilitation Medicine [12, 13] formulates the basic objective of PRM: increase of patients' quality of life, especially autonomy in everyday activities [40]. Tasks of PRM are oriented to amelioration of functioning and participation in different types of activities [12, 13, 41–43].

Modern rehabilitation algorithm requires a detailed functional evaluation, based on International Classification of Diseases; International Classification of Functioning, disability and Health (ICF) and on clinical principles [44–46]. In rehabilitation clinical practice, we apply a complex rehabilitation programme, combination of different physical factors, in some cases—with drugs.

We consider that the complex algorithm for pain management must include: systematic drugs (and vitamins); rehabilitation complex, and patient education.

The complex PRM algorithm includes a detailed functional assessment of the patient and a complex rehabilitation programme. Functional evaluation emphasizes on goniometry, manual muscle test, grasp and gait evaluation, autonomy in everyday activities, ICF evaluation, Visual analogue scale for pain /VAS 0-10/, McGill Pain questionnaire) [47]. The rehabilitation program is established by synergic combination of different natural and preformed physical modalities (kinesiotherapy and ergotherapy, cryo and peloido-procedures, electrotherapy and photo-therapy, magnetic field, etc.). This program must include: *one or two pre-formed modalities; one thermo- or kryo-agent; one or two physiotherapeutic procedures* (including analytic exercises, soft tissue techniques, manual therapy, etc.).

At the end of every rehabilitation course, it is obligatory to realize a functional assessment—with the goal to evaluate the efficacy and to prescribe the consecutive rehabilitation procedures.

During our modest clinical experience (of 30 years) we received multiple significant results in patients with conditions of the nervous and motor systems [48–52]. We realized comparative evaluation between the efficacy of pure drug therapy, physical analgesia and combined anti-pain therapy *(drug and physical analgesia)* on different types of pain: spastic pain; rigidity pain; hemiparetic shoulder pain and hemiplegic hand pain; paravertebral (upper & low back) pain; radicular neuropathic pain; diabetic polyneuropathy pain; arthrosis pain; arthritis pain; scoliotic pain; posttraumatic pain; post-operative pain; phantom pain.
