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

OBJECTIVE: To evaluate the efficacy of radicular decompression in lumbar spinal stenosis using a microendoscopic technique. METHODS: 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. RESULTS: 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). CONCLUSION: Data indicate that, in our experience, on midterm follow-up, microendoscopic laminectomy decompression is an effective technique for the treatment of lumbar spinal stenosis.