Noninstrumented Lumbar Fusion with Bone Morphogenetic Proteins for Spinal Stenosis with Spondylolisthesis in the Elderly

Abstract

This study examined the use of noninstrumented posterolateral lumbar fusion with bone morphogenetic protein (BMP) and compared its effectiveness with that of instrumented fusion for the treatment of lumbar spinal stenosis (LSS) with spondylolisthesis in elderly patients. This study was a retrospective review of 93 patients treated in a single-surgeon neurosurgical private practice over a 15-year period. Fifty-nine patients over the age of 65 who underwent noninstrumented posterolateral fusion with rhBMP-2 (Infuse) for LSS with spondylolisthesis were compared with 34 patients who underwent instrumented fusion without rhBMP-2. Outcomes in terms of reoperation rate, pain improvement, Oswestry Disability Index (ODI) score, and number of extra follow-up visits due to persistent problems were characterized by the use of t tests and χ2 tests. The reoperation rate in the noninstrumented rhBMP-2 fusion group was significantly lower than in the instrumented fusion group (17.6% vs. 3.4%, P= 0.048). The mean pain improvement was significantly higher in the noninstrumented rhBMP-2 group at 3 months (8.1 vs. 6.0, P < 0.001, 95% confidence interval [CI] 1.2 to 3.0) and at 1 year (7.25 vs. 5.6, P= 0.030, 95% CI 0.3 to 3.1). The ODI score improvement was significantly higher in the noninstrumented rhBMP-2 group (51 vs. 42.8, P < 0.001, 95% CI 4.7 to 11.6). The mean number of additional follow-up visits per patient was significantly lower in the noninstrumented rhBMP-2 group (0.068 vs. 1.23, P < 0.001, 95% CI 0.59 to 1.75). Noninstrumented posterolateral lumbar fusion with rhBMP-2 in elderly patients with LSS and spondylolisthesis is a viable alternative to instrumented fusion based on clinical outcomes measured in this study.