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Objective: Bone morphogenetic protein (BMP) was first approved in 2002 for use in single-level anterior lumbar fusions as an alternative to iliac crest grafts. Subsequent studies have concluded that BMP provides superior fusions rates and therefore reduces reoperations for nonunions. The purpose of this study was to determine the reoperation rates for symptomatic nonunions in posterior cervical (subaxial) spinal fusions with and without the use of BMP and to determine if the nonunion rates are statistically significantly different between the two groups., Methods: Between January 2009 and September 2013, the authors identified 1158 posterior cervical spinal fusion cases in the subaxial spine (C2-7) from a large spine registry (Kaiser Permanente). Patient characteristics, diagnoses, operative times, lengths of stay, and reoperations were extracted from the registry. Reoperations for symptomatic nonunions were adjudicated via chart review. Logistic regression was conducted to produce estimates of odds ratios (OR) and 95% confidence intervals (CIs). Kaplan-Meier curves for the non-BMP and BMP groups were generated and compared using the log-rank test., Results: In this cohort there were 1158 patients (19.3% with BMP) with a median follow up of 1.7 years (interquartile range [IQR] 0.7-2.9 years) and median duration to operative nonunion of 0.63 years (IQR 0.44-1.57 years). Kaplan-Meier curves showed no significant difference in reoperation rates for nonunions using the log-rank test (p = 0.179). In a subset of patients with more than 1 year of follow-up, 788 patients were identified (22.5% with BMP) with a median follow-up duration of 2.5 years (IQR 1.7-3.4 years) and a median time to operative nonunion of 0.73 years (IQR 0.44-1.57 years). There was no statistically significant difference in the symptomatic operative nonunion rates for posterior cervical (subaxial) fusions with BMP compared with non-BMP (1.1% vs. 0.7%; crude OR 1.73, 95% CI 0.32-9.55, p = 0.527) for more than 1 year of follow-up., Conclusions: This study presents the largest series of patients using BMP in posterior cervical (subaxial) spinal fusions. Reoperation rates for symptomatic nonunions with more than 1 year of follow-up were found to be 1.1% with BMP and 0.7% without BMP. There was no significant difference in the reoperation rates for symptomatic nonunions with or without BMP.

Study Design: A retrospective cohort study with medical record review., Objective: To determine if there is difference in the operative nonunion rates with and without the use of bone morphogenetic protein (BMP) after spinal fusions by analyzing data from an integrated health care system's spine registry., Summary of Background Data: BMP was first approved in 2002 for use in single-level anterior lumbar fusions. Follow-up studies have advocated its use in reducing the need for reoperations for nonunions. Recent studies, however, have questioned these conclusions and the usefulness of BMP in spinal fusions has been highly debated., Methods: We identified 9425 spinal fusion cases between 2009 and 2011 from a spine registry in a large integrated health care organization. Patient characteristics, diagnosis, operative times, length of stay, and reoperations were extracted from the registry. Reoperations for nonunions were adjudicated via medical record review. Cox regression models were used to evaluate the risk of reoperation while adjusting for confounders., Results: In our cohort, there were 5456 BMP cases and 3969 non-BMP cases. The mean age was 60.4 years (standard deviation: 12.9 yr), with the majority being females (53%). The median follow-up time was 1.2 years (interquartile range: 0.6-2.0 yr). Reoperation rates for BMP versus non-BMP nonunions for all fusion cases with follow-up of 1 year or more (1.9% vs. 2.2%) and follow-up of 2 years or more (2.3% vs. 2.6%) were not statistically significantly different. Operative nonunion rates did not reach statistical significance for different spine regions and for different fused columns (anterior only, posterior only, or combined). After controlling for differences in patient characteristics, operative times, levels fused, and spinal regions, the risk of reoperation in the BMP versus non-BMP groups was 0.67 (95% CI: 0.42-1.06)., Conclusion: In this large cohort of spinal fusions at all spine regions involving all fused columns with and without BMP, we found no statistically significant difference in operative nonunion rates., Level of Evidence: 3.