Midterm outcome after microendoscopic decompressive laminotomy for lumbar spinal stenosis: 4-year prospective study.

Abstract

To evaluate the efficacy of radicular decompression in lumbar spinal stenosis using a microendoscopic technique. This was a longitudinal prospective study of 50 patients with a diagnosis of lumbar spinal stenosis who were treated by microendoscopic decompression using an 18-mm METRx tubular retractor according to the METRx technique (Medtronic Sofamor Danek, Memphis, TN). Twenty of the patients had an additional disc prolapse, and a microendoscopic discectomy was associated with decompressive laminectomy. The results were evaluated using the visual analog scale pain score, Oswestry Disability Index score, patient satisfaction questionnaire, and modified Macnab classification. The average age of the patients was 56 years; 29 (58%) were men and 21 (42%) were women. The most commonly affected level was L4-L5 (64%). The mean surgical intervention time was 94.3 (+/- 14.3) minutes. Mean postoperative hospital stay was 3.16 (+/- 2.3) days. The follow-up time after surgery was 4 years (48 +/- 6.6 months; range, 24-72 months). We obtained good or excellent results in 72% of patients, achieving good subjective satisfaction in 68% of the patients. The mean decrease in the Oswestry Disability Index score was 30.23 (+/- 24.29), the mean decrease in the leg pain visual analog scale score was 6.02 (+/- 2.57), and the mean decrease in the lumbar pain visual analog scale score was 0.84 (+/- 2.06). Adjusted mean differences were in all cases statistically significant (P < 0.05). Data indicate that, in our experience, on midterm follow-up, microendoscopic laminectomy decompression is an effective technique for the treatment of lumbar spinal stenosis.