Is rhBMP-2 Worth the Risk? A Data-Driven Look at Fusion Outcomes and rhBMP-2-Related Complication Burden in High-Risk Adult Spinal Deformity Patients.

Abstract

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is widely used to enhance spinal fusion, yet its use remains controversial due to complication concerns. Evidence regarding its efficacy and safety, particularly in patients with biologically higher risk of pseudarthrosis, remains incomplete. Therefore, in patients undergoing adult spinal deformity (ASD) surgery, we sought to evaluate the association between rhBMP-2 use and outcomes, with dedicated analyses of high pseudarthrosis risk groups (obesity, diabetes, and osteoporosis/osteopenia). A retrospective cohort study was performed of adult patients undergoing ASD surgery involving ≥5-level instrumented fusion between 2009 and 2023, with at least 2 years of follow-up. Patients were stratified based on intraoperative rhBMP-2 use. Primary outcome was pseudarthrosis/rod fracture, as this relates directly to the fusion process. Secondary outcomes were BMP-associated adverse events including new-onset radiculitis, wound complications, and seroma. Univariate and multivariable logistic regression adjusted for relevant confounders. Among 288 patients undergoing ASD surgery (mean age: 62.5 ± 17.5 years; 74.0% women), 118 (41.0%) received rhBMP-2. In the entire study population, rhBMP-2 use independently reduced risk of pseudarthrosis/rod fracture (16.1% vs 38.2%, P < .001; odds ratio [OR] = 0.14, 95% CI: 0.02-0.78, P = .025). rhBMP-2 was not independently associated with radiculitis, wound complications, or seroma formation. In the osteoporotic/osteopenia subgroup, rhBMP-2 use was independently associated with reduced risk of pseudarthrosis/rod fracture (20.0% vs 56.3%, P < .001, OR = 0.21, 95% CI: 0.07-0.69, P = .010). In the obesity subgroup, rhBMP-2 use was independently associated with reduced risk of mechanical complications (46.0% vs 66.1%, P = .037; OR 0.17, 95% CI: 0.04-0.80, P = .024). No significant positive effect of rhBMP-2 use was found in the diabetic subgroup. In a cohort of patients undergoing ASD surgery, rhBMP-2 use was independently associated with fewer mechanical complications without an increase in BMP-related adverse events. rhBMP-2 demonstrated differential efficacy across high-risk populations, specifically benefiting patients with obesity and osteoporosis/osteopenia.