Preliminary study showing safety/efficacy of nanoss bioactive versus vitoss as bone graft expanders for lumbar noninstrumented fusions

BACKGROUND: The lateral fusion mass for multilevel lumbar laminectomies with noninstrumented posterolateral fusions now often utilizes lamina autograft and bone marrow aspirate (BMA) mixed with one of two bone graft expanders: either Vitoss (Orthovita, Malvern, PA, USA) or NanOss Bioactive (Regeneration Technologies Corporation: RTI, Alachua, FL, USA). METHODS: Here, we compared two sequential prospective the times to fusion, fusion rates, complications, and infection rates for two prospective cohorts of patients utilizing either Vitoss (first 213 patients) or NanOss (subsequent 45 patients) respectively, undergoing multilevel lumbar laminectomies (average 4.6 vs. 4.5 levels) with noninstrumented fusions (average 1.3 vs. 1.2 levels). Surgery addressed stenosis/ossification of the yellow ligament (OYL) (all patients), with subsets exhibiting degenerative spondylolisthesis synovial cysts, and disc disease. Fusion was documented by two independent neuroradiologists blinded to the study design, utilizing dynamic X-rays and two dimensional computed tomography (2D-CT) studies up to 6 months postoperatively, and up to 1 year where indicated. RESULTS: Comparison of patients receiving Vitoss versus NanOss as bone graft expanders revealed nearly comparable; times to fusion (5.3 months vs. 4.8 months), fusion rates (210 [98.6%] vs. 45 [100%] patients), pseudarthroses (3 [1.4%] vs. 0), postoperative seromas (2 [0.94%] vs. 0), and deep wound infections (2 [0.94%] vs. 0). CONCLUSION: In this preliminary study of patients undergoing multilevel lumbar lamienctomies with posterolateral noninstrumented fusions, results were nearly comparable utilizing Vitoss or NanOss as bone graft expanders. Although the number of NanOss patients was substantially lower, the comparable efficacy and absence of postoperative complications for noninstrumented fusions is promising.