Chronic Pain Syndromes in Postganglionic Lesions of Nervous Structures Formed from Roots of the Spinal Cord (Pathogenesis, Clinical Picture, Microsurgery)

M.G. Ryabykin

(Chair of Neurosurgery, Russian Medical Academy of Postgraduate Education, Moscow)

Severe chronic pain syndromes in postganglionic lesions of nervous structures, formed from roots of the spinal cord, are one of the urgent problems of functional neurosurgery. Destruction of entrance zones of posterior roots (EZPR) is the most effective operation of all existing surgical ways of treatment. It served the basis for development of new surgical methods with applying ultrasonic instruments.

We performed 45 operations in 43 cases: 21 in phantom pain syndrome, 7 in tumors of nervous structures, 4 in postmastectomy syndrome, 6 in intercostal neuralgia, 3 in posttraumatic plexopathy, 4 in deafferentation syndrome against a background of osteochondrosis. There were three versions of operations on EZPR: ultrasonic posterior selective rhizidiotomy (19 operations), ultrasonic destruction in combination with posterior selective rhizidiotomy (4), ultrasonic rhizomyelotomy (23). Results were estimated as good, satisfactory and bad, depending on a degree of pain syndrome elimination. Good, satisfactory and bad results were watched in 31 (68.9%), 11 (24.4%) and 3 (6.7%) out of 45 operated patients.

Methods of creating an experimental chronic pain syndrome model in postganglionic lesions of nervous structures were developed. Development of pain syndrome was typical of 6 out of 20 operated rats. Morphologic studies of experimental material, carried out on the 101 day after operation, revealed nonspecific heterogenous pathohistologic changes both of a destructive and reparative character, marked to a different extent. They were watched at the segmental level and in the above-lying parts of the CNS. It reflected a transneuronal response to deafferentaton of segments of the spinal cord, corresponding to a lesion. The results of morphologic studies, carried out on the above experimental model of chronic pain syndrome and success of operations on EZPR, confirm a generator mechanism of this syndrome development in a postganglionic lesion of nervous structures.