Motor deficit in lumbar spinal stenosis: a retrospective study of a series of 50 patients.

Severe motor weakness is an infrequent symptom in the course of lumbar stenosis. The objectives of this study are threefold: to describe the motor deficit, evaluate the prognosis factors, and determine the type of stenosis most likely to be complicated by motor loss. Fifty consecutive patients with a mean age of 65 years, operated on for a lumbar stenosis and with a severe motor deficit, have been retrospectively studied with a mean follow-up of 38 months. The overall functional result was evaluated according to the Beaujon scoring system. The motor capacity was rated from 0 (complete paralysis) to 5 (normal strength). Prognosis factors were investigated with a multivariate analysis model. Motor weakness was rated as zero 11 times, as one 8 times, as two 8 times, and as three 23 times. According to our rating scale, the overall results were considered excellent in 25 cases, good in 17 cases, and fair in the 8 remaining cases. Regression of motor weakness was complete 15 times, partial 25 times, and null 10 times. In this study, favorable prognosis parameters of motor weakness recovery were as follows: association with a discal herniation, stenosis at one level, preoperative duration of motor weakness <6 weeks, age <65, and monoradicular deficit. In contrast, severity of the initial motor weakness, association with sphincter abnormalities, presence or not of degenerative spondylolisthesis, or of a complete block on the myelogram were not influential variables.