P.M. Gioev, E.A. Davydov, A.V. Omelchenko
(Polenov Research Neurosurgical Institute, Saint Petersburg)
Stenosis of a vertebral canal at a lumbar level is one of the most frequent causes of pain syndrome, as well as a syndrome of “unsuccessful operation on the spine”, resulting in disability.
According to different authors, “a narrow vertebral canal” is watched in 0.55-8.3% of cases, operated for radicular syndrome. The last decades have been characterized by a marked increase of a number of patients with stenosis of a vertebral canal, which is conditioned by introduction of CT and MRI examinations into world clinical practice. The problem of choosing tactics of management of this pathology at a lumbar level in general and its surgery in particular is still open. Interventions are considered to be the main type of surgical treatment. It includes such methods as laminectomy and hemilaminectomy. However, they are characterized by a high rate of poor results (25%), manifesting themselves in augmentation of motor disorders, appearance of restenosis and a syndrome of “unsuccessful operation on the spine”. Such new methods as modified hemilaminectomy and modified laminectomy have been proposed with the purpose of improving quality of surgical treatment of stenoses at a lumbar level (Gioev P.M., 1997).
The analysis of clinical-and-neurological manifestations of a vertebral canal stenosis allowed the authors to distinguish between two types of a clinical course: unilateral and bilateral ones. Pain syndrome and symptoms of a root (roots) function absence on one or both sides were used as criteria for determining a type of a clinical course. The majority of patients had bilateral symptoms (78%). Stenoses of a vertebral canal with bilateral and unilateral symptoms were usually located at the LIV-LV level and LV-SI level respectively. The study allowed to determine leading symptoms of the disease and to get instrumental data, depending on a type of its clinical course.
The method by Gioev P.M. was used in 50 cases. Treatment consisted in modified hemilaminectomy or laminectomy. When root decompression was necessary, foraminotomy was performed on one or both sides. Some patients underwent spondylodesis. In case of multilevel stenosis of a vertebral canal decompression was performed only at a clinically significant the level.
The nearest and long-term results of surgical treatment of cases with stenoses of a vertebral canal showed, that modified interventions could be regarded to be safe methods of treatment. A volume of necessary decompression depended on a type of a clinical course.
Thus, as for cases with unilateral symptoms, adequate decompression with positive dynamics of neurological disorders can be achieved by using modified hemilaminectomy, as its clinical efficacy is in compliance with a volume of necessary manipulations. This method can be regarded only as the first stage of treatment in cases with stenosis of a vertebral canal and bilateral clinical manifestations, because it has no negative effect on a supporting function of the spine.
Modified laminectomy (hemilaminectomy) can be an operation of choice in stenoses of a vertebral anal at a lumbar level.