Posterolateral lumbar fusion for degenerative spondylolisthesis: experiences of a modified technique without instrumentation.

From 1985 to 1994, 66 patients who had symptomatic degenerative spondylolisthesis of lumbar and lumbosacral levels managed by modified technique for decompressive laminectomy and postero-lateral spinal fusion. There were six males and sixty females with a mean age of 58.5 years (range, 47-73). Fifty- five patients had spondylolisthesis at L4-L5 level (51 were grade I and 4 were grade II), nine patients had spondylolisthesis at L5-S1 level (7 were grade I, 2 were grade II). There were two patients who had spondylolisthesis of both levels. Mean follow-up time was 48 months (range, 12-120 months). There were excellent and good results in 57 cases (86.4%), fair in 6 cases (9.1%). Three cases (5%) had poor results; 2 cases developed non-union, one case had L4 and L5 roots injury during operation. The overall fusion rate was 96 per cent. Solid spinal fusion occurred within 6 months. No further slip occurred in any cases in this study.