The Role of Recombinant Human Bone Morphogenetic Protein-2 in Atlantoaxial Arthrodesis: Institutional Predictors and Systematic Review of Outcomes.

Background/

Objectives

To evaluate the safety, efficacy, and predictors of rhBMP-2 use in atlantoaxial (C1-2) fusion through institutional outcomes and a pooled analysis from the literature.

Methods

We retrospectively analyzed adult patients who underwent C1-2 fusion at a tertiary care center between 2015 and 2020. Primary outcomes included radiographic fusion and postoperative complications. Univariate logistic regression was used to identify predictors of intraoperative rhBMP-2 use. A subset of eight patients who underwent isolated C1-2 fusion using rhBMP-2 were analyzed and evaluated against 260 cases from a PRISMA-compliant systematic review of the literature.

Results

Among our 49 patients (mean age, 61.8 ± 22.8 years; 57% female), 24 (49%) received rhBMP-2. Radiographic fusion or early signs were observed in 89.8% of patients, with no significant difference between rhBMP-2 and non-rhBMP-2 groups (p = 0.678). Complications were similar (12.5% vs. 25.0%, p = 0.702). All postoperative instabilities occurred in non-rhBMP-2 patients (p = 0.043). Degenerative pathology was associated with increased use of rhBMP-2 (OR of 7.96, p = 0.051), while trauma was associated with decreased use (OR of 0.21, p = 0.019). Among the eight local isolated cases, seven achieved fusion and none required revision. Our literature review yielded a group of 260 patients, 241 of which achieved successful fusion with a complication rate of 10.8% and a revision surgery rate of 3.8%.

Conclusions

rhBMP-2 appears to be a safe and effective adjunct in C1-2 fusion, with outcomes comparable to alternative techniques. Although off-label, its selective use may benefit patients at risk of nonunion. Interpretation should be tempered by the retrospective design and heterogeneity across cohorts; pooled rates are descriptive. Further prospective studies are needed to establish standardized protocols, optimal dosing, and long-term efficacy.