Advantages of a Microsurgical Translaminar Approach (Keyhole Laminotomy) for Upper Lumbar Disc Herniation

BACKGROUND: To prevent risk of iatrogenic instability after surgery for upper lumbar disc herniation, we adapted a microsurgical translaminar approach (keyhole laminotomy), which allows less destructive laminotomy. We compared results of translaminar and interlaminar approaches. METHODS: The study enrolled 48 patients who underwent single-level discectomy in the upper lumbar spine (L1-2 or L2-3). Patients were allocated to 2 groups: a translaminar group (n = 20) or an interlaminar group in = 28). Mean patient age was 57.04 +/- 12.77 years, and median follow-up duration was 3.5 years (range, 1.0-7.0 years). Clinical and radiologic data were retrospectively reviewed. RESULTS: Baseline characteristics, including age, sex, surgical level, and preoperative symptoms, were nonsignificantly different. At 1 year after surgery, improvement in leg pain as determined by visual analog scale was nonsignificantly different. Improvement in visual analog scale for back pain was significantly greater in the translaminar group compared with interlaminar group (mean 4.00 +/- 1.56 vs. 2.45 +/- 2.01, P < 0.001). Surgical outcome was not different between groups. Mean decrease in disc height at operated level was not significantly different between groups. Mean increase in segmental range of motion at surgical levels was significantly greater in the interlaminar group (-3.38 +/- 4.03 degrees vs. 1.10 +/- 3.03 degrees , P = 0.010), and mean recovery of total lumbar lordosis was significantly greater in the translaminar group (9.80 +/- 5.96 degrees vs. 0.43 +/- 8.45 degrees, P = 0.021). CONCLUSIONS: The translaminar approach provides a safe and effective alternative to the classic interlaminar approach for upper lumbar disc herniation.