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[Lumbar spinal stenosis. Symptomatology and methods of treatment].

INTRODUCTION
Lumbar spinal stenosis (LSS) may be defined as any type of the narrowing of the spinal nerve root canal (the lateral recess), intervertebral foramina, or its combination. It may be local, segmental or generalized; it can be caused by bone or soft tissue, and the narrowing can involve the bony canal or the dural sac or both. The normal sagital diameter of the lumbar canal is 15 to 25 mm and measurements below this are regarded as suggestively abnormal; a diameter less than 12 mm confirms the presence of stenosis. On the other hand, the lateral recess height less than 3 mm is suggestive, and less than 2 mm is a diagnostic sign of stenosis. There are two large groups of LSS: congenital-developmental stenosis and acquired stenosis with many subgroups (Scheme 1). The number of surgical operations due to LSS is increased during the ensuing years especially in elderly persons. This is why we would like to emphasize the important role of this phenomenon as there are only a few published papers in domestic literature.


MATERIAL AND METHODS
In a consecutive series of 38 patients with LSS diagnosed for the last five years (January 1990-December 1994), aged from 20 to 70 years (average age 48.55) there were 21 males (Table 1); 34 of them had LSS as a result of bony changes, while the rest of 4 were iatrogenic (3 after disc extirpation and one after laminectomy) (Fig. 1). Herniation of the nucleus pulposus in combination with LSS was found in 12 patients (31.57%). Local segmental stenosis was identified in 16 patients (42.10%). (Graph. 1) (Fig. 2); the others had the generalized type of stenosis involving two levels (17 patients-44.7%); three levels (4 patients-10.52%) or 4 levels (one patient-2.63%) (Fig. 3). As far as symptomatology is concerned 31 patients had low-back pain with acute radicular complaints and motor weakness as the result of lesion of one or two spinal roots (20 patients). There were no neurogenic claudication or cauda equina compression syndromes. Electromyoneurographic studies (EMNG) in surgically treated patients revealed preoperative signs of muscle denervation in 15 patients (7.42%) (Table 2); the rest of them had signs of chronic irritative lesions of the corresponding root.


RESULTS
Twenty one patients were operated on: 19 with signs and symptoms of generalized type of LSS and only two with lateral recess stenosis (Table 2). Congenital developmental stenosis was identified in 6 young patients (20 to 40 years of age) (Fig. 4). Single-level laminectomy with medial facetectomy and nerve root decompression was performed in 10 patients, and the rest of them had two level or three level decompressive laminectomies with medial facetectomy and roots decompression (Fig. 5). Dissectomy was done in 8 patients (Graph 2). None of our patients had concomitant arthrodesis, or needed reoperation. Postoperative EMNG improvement was confirmed in 13 patients of 15 (86.66%); this is about 61.90% in comparison to all operated patients (Table 3). The main complaints after the operation were: low-back pain (70%), leg numbness (70%), slight walking difficulties (60%); however all were able to walk more than 500 meters. The answer to the question how they felt after the operation, 15 patients responded to feel better or much better (71.42%), 3 felt the same (14.28%), and 3 felt worse than before the operation. Five patients retired before the operation, 7 changed their occupation taking an easier job, 9 returned to the same job, and none retired after the operation (Table 3).


DISCUSSION
A certain number of patients had congenital-developmental stenosis with thickening of the laminae and development of short, squat pedicles with a decreased anterior-posterior diameter of the spinal canal. There are numerous variations of this pattern which remain asymptomatic until later developmental changes precipitate the typical radiculopathy and cauda equina changes in LSS. (ABSTRACT TRUNCATED)