Surgical methods of treating pain

Surgical methods of treating pain syndromes can be divided into three groups:

• anatomical;
• destructive;
• methods of neuromodulation

Anatomic operations are represented by decompression, transposition and neurolisis. In the presence of indications they are more often performed at the first stage of surgical treatment and are in many cases pathogenetically directed. It is well known that the most complete functional result of surgical treatment of trigeminal neuralgia is achieved by microvascular decompression of the spinal nerve root. This operation is in this case the only pathogenetically substantiated and often allows to completely eliminate the pain syndrome. Wide application of anatomical operations was found in the surgical treatment of tunnel syndromes. Such "anatomical" operations as meningoradiculolysis, explorative laminectomies with excision of scars and adhesions, especially repeated operations of this kind, have not been practically used in the developed countries of the world in recent years. They are considered not only useless, but often cause the formation of even more coarse adhesions and scars.

Destructive operations are interventions in various departments of the peripheral and central nervous system, whose purpose is to cut or destroy the ways of pain sensitivity and destruction of structures that perceive and process pain information in the spinal cord and brain.

Previously, it was believed that cutting the pathways of pain sensitivity or the rupture of structures that perceive it can prevent and the pathogenesis of pain. Many years of experience in the use of destructive operations have shown that, despite their high enough effectiveness in the early period, in most cases, pain syndromes recur. Even after radical interventions aimed at destroying and crossing the nociceptive pathways of the brain and spinal cord, a relapse of pain syndrome occurs in 60-90% of cases. Destruction of the nerve structures in itself can lead to the formation of GPOO, and, more importantly, promotes the spread of the pathological activity of neurons to higher "floors" of the central nervous system, which in practice leads to relapse of the pain syndrome in a more severe form. In addition, destructive operations due to their irreversibility in 30% of cases cause severe complications (paresis, paralysis, dysfunction of the pelvic organs, painful paresthesias and even disturbances in the vital functions).

At present, in the developed countries of the world destructive operations are used only for a limited number of practically doomed patients with severe forms of chronic pain that can not be controlled by any other methods of influence. The exception to this rule is the DREZ operation. It is a selective transection of sensitive fibers in the zone of the entrance of the posterior roots into the spinal cord. At present, indications for DREZ operations are limited to cases of preganglionic tearing of the primary trunks of the brachial plexus. It should be emphasized the need for careful selection of patients for this operation, since the "centralization" of pain with the presence of pronounced signs of deafferentation makes the forecast of such operations extremely unfavorable.

Neuromodulation - methods of electrical or mediator action on the peripheral and / or central nervous system, which modulate the motor and sensory responses of the body by restructuring the disturbed mechanisms of self-regulation of the central nervous system. Neuromodulation is divided into two main methods

• Neurostimulation - electrical stimulation (ES) of peripheral nerves, spinal cord and brain;
• method of dosed intrathecal administration of drugs, with the help of programmable pumps (often used in cancer pain syndromes or in ineffective neurostimulation.)

In the treatment of non-oncological pain syndromes, the methods of neurostimulation are more often used, which can be divided into:

• electrical stimulation of the spinal cord;
• electrical stimulation of peripheral nerves;
• electric stimulation of deep structures of the brain;
• electric stimulation of the central (motor) cortex of the brain.

The most common of the methods listed above is chronic spinal cord stimulation (CCCM). The mechanism of action of CCSS:

1. electrophysiological blockade of pain impulses;
2. the development of mediators of antinociception (GABA, serotonin, glycine, noradrenaline, etc.) and the intensification of the descending influences of the antinociceptive system;
3. peripheral vasodilation, due to the impact on the sympathetic nervous system.

Most authors distinguish the following main indications for neurostimulation:

• Failed back surgery syndrome "(FBSS), which translates as a syndrome of" failed operations on the spinal column ", it is also called" post-aminectomy syndrome "," syndrome of the operated spine, etc. ";
• neuropathic pain in the lesion of one or more peripheral nerves (after minor injuries and injuries, operations, infringement (compression) of soft tissues or the nerve trunks themselves, as well as due to inflammatory and metabolic disorders (polyneuropathy));
• complex regional pain syndrome (CRPS) of type I and II;
• postherpetic neuralgia;
• post-amputation stump pain;
• postoperative pain syndromes - post-thoracotomic, postmastectomic, post-laparotomic (except for FBSS and post-mutation);
• pain in the extremities associated with impaired peripheral circulation (Raynaud's disease, obliterating endarteritis, Buerger's disease, Lerish's syndrome and others);
• angina (the implantation of a system for chronic stimulation, wonders not only the pain, but also its cause - spasm of the coronary vessels and accordingly ischemia, often being an alternative to shunting operations);
• with pelvic pain the XPSM method is less effective, but it is the chronic stimulation (of the spinal cord or branches of the sacral plexus) that is often effective in cases where conservative methods are powerless, and direct surgery on the pelvic organs is not shown;
• deafferentation pain in the extremities, for example, with the defeat of the brachial plexus postganglionic type or partial damage to the spinal cord. Pain due to preganglionic detachment of the brachial plexus, unlike postganglionic lesions, is much worse than electrical stimulation of the spinal cord. Effective operation in this case remains DREZ-operation. However, considering the above-described disadvantages of destructive interventions, it is desirable to perform it in case of unsuccessful results of chronic electrostimulation. Further development of methods of neurostimulation and, in particular, the emergence of the method of chronic electric stimulation of the central cortex of the brain caused the use of DREZ-operations or ineffectiveness of HRSSM

At present, electric stimulation of the motor cortex of the brain can be a non-destructive alternative to DREZ operations. The main criteria for selecting patients are:

• the severity of the pain syndrome and its impact on the quality of life (on a visual analogue scale of 5 points and above);
• ineffectiveness of medical and other methods of conservative treatment (more than 3 months);
• absence of indications for direct surgical intervention (for anatomical operations);
• positive results of test electrical stimulation.

The main contraindications to neurostimulation are as follows:

• severe concomitant somatic pathology;
• non-drug dependence;
• presence in the anamnesis of suicidal attempts accompanying a serious mental pathology;
• mental disorders with obvious signs of somatization;
• intellectual limitation of the patient, preventing the use of the system for electrical stimulation.

[1], [2], [3]