THE PREDICTIVE VALUE OF PREOPERATIVE MYELOGRAPHY IN LUMBAR SPINAL STENOSIS

Study Design. Restrospective follow-up study on the significance of myelographic findings on the postoperative results of patients with lumbar canal stenosis is not well defined. Objectives. The authors studied the predictive influence of preoperative myelography on the outcome of patients with surgically treated lumbar spinal stenosis, defined by an upper limit of anteroposterior diameter of the dural sac on the lateral myelogram film of equal to or less than 12 mm. Summary of Background Data. Patients with prior lumbar surgery were excluded. There were 251 patients (women 44% and men 56%) with a mean age of 55 years and a mean follow-up time of 4.2 years. Methods. Patients with complete block or subtotal block on myelography were included in the block stenosis group, patients with an anteroposterior diameter of less than 10 mm were included in the absolute stenosis group and patients with an anteroposterior diameter of 10-12 mm were included in the relative stenosis group. Results. The proportion of good-to-excellent outcomes was 76% in block stenosis, 56% in absolute stenosis, and 61% in relative stenosis. In the multivariate analysis, the pre-preoperative variables that correlated with good outcome were block stenosis and male sex. Conclusions. The severity of myelographic findings is significantly related to the outcome of patients who underwent surgeries for lumbar canal stenosis.