A.K. Dulaev, V.P. Orlov, K.A. Nadulich, A.V. Teremshonok
(Medicomilitary Academy, Saint Petersburg)
The authors deal with experience of surgical treatment of 214 cases with degenerative-dystrophic diseases of the lumbosacral spine, admitted to the Medicomilitary Academy in 2001-2007. Their age varied from 19 up to 82 years.
Results of multimodality examination (conventional and functional X-ray, positive myelography, CT, CT-densitometry, MRI, estimation of a general and local status) were used for determination of main pathologic factors, being a cause of persistent pain syndrome, and additional factors, effecting a choice of surgical tactics and outcome. The former included compression of neurovascular elements of a vertebral canal (local and central forms of stenosis and their combinations of discogenic and non-discogenic origin; 95% of cases), impaired stability of vertebrolocomotive segments (hypermobility, instability; 25%), significant changes of a sagittal and frontal profile (segmental kyphosis, scoliosis and spondylolisthesis, affecting a body balance and demanding instrumental correction; 18%). A combination of these three pathologic factors was watched in 27% of cases. Additional pathologic factors were as follows: a number of affected vertebrolocomotive segments, demanding surgical correction; a state of structures, adjacent to affected segments (presence and localization of protrusions of intervertebral discs, segmental instability, a tendency to a vertebral canal stenosis), and reduced mineral density of lumbar vertebral bodies.
The analysis of a combination of pathologic factors in each specific case allowed to determine a goal of operation (decompression of neurovascular elements, spine stabilization, correction of its impaired profile) and an individual program of surgical treatment (use of different methods in decompression of the spinal cord elements, instrumental correction and osteoplastic stabilization of the spine).
In case of local compression of the spinal cord roots we applied local (microsurgical) methods of decompression (interlaminectomy, isthmotomy, fenestration of a laminar part of a vertebral arch). Laminectomy with sparing resection of articular processes on both sides (up to 50%) was performed in central stenosis. Pathology of this type was characteristic of cases above 55-60, in whom stability of a vertebrolocomotive segment was often conditioned by accompanying fibrosis of an intervertebral disc, deforming spondylosis, etc. During the last years removal of intervertebral disc hernias in young cases was followed by dynamic stabilization of a segment with the DIAM interspinal device. When an adjacent vertebrolocomotive segment was affected, the DIAM implants were placed at two levels.
Instability of a vertebrolocomotive segment demanded instrumental fixation of the spine, combined with osteoplastic spondylodesis. Restoration of sagittal profile of the lumbosacral spine was achieved by contraction of posterior vertebral segments (lordosis restoration) after decompression. Choosing a method of osteoplastic stabilization (PLF, PLIF, TLIF), we took into account both initial instability and a degree of impaired segmental stability of the spine, which arose during an operation and resulted from resection of the posterior supporting complex.
Additional pathologic factors had a considerable impact on a choice of surgical tactics. Three-level operations in young cases were always accompanied by transpedicular fixation, combined with posterolateral spondylodesis. In case of marked degenerative changes at the levels, adjacent to affected segments, they were included into a zone of fixation. If these changes had an initial character, their dynamic stabilization was performed with applying the DIAM implants. Presence of marked osteoporosis of lumbar vertebral bodies was a contraindication for instrumental fixation of the spine. In such cases we preferred to use minimum destabilizing methods of decompression (a port-hole technique). Initial impairment of segment stability was treated with posterolateral spondylodesis (PLF) and postoperative external immobilization of the spine by a rigid jacket.
Use of rational surgical tactics in treatment of degenerative-dystrophic diseases of the lumbosacral spine made it possible to get excellent and good anatomic-functional results in 88% of cases (a follow-up period of 2-7 years). Satisfactory and poor results were observed in 8% and 4% of cases respectively.