rhBMP-2 Increases Fusion Rates and Immediate Postoperative Pain after Spinal Fusion: A Meta-Analysis
The Annals of Internal Medicine recently published a meta-analysis of the safety and effectiveness of recombinant human bone morphogenetic protein-2 for spinal fusion, regardless of spinal level or surgical approach. Given the rise in spinal fusions and the increased use of rhBMP-2 as an alternative to autologous grafts, this critical evaluation is timely and applicable to spine surgeons. Study conclusions were based on data from 1408 individual participants in 11 eligible RCTs, including all trials sponsored by Medtronic. In addition, safety was assessed by reviewing all observational studies that reported rhBMP-2-related adverse events. The authors conclude that at 24 months, compared to iliac crest bone graft, rhBMP-2 increases fusion rates by 12% (CI, 2% to 23%), decreases disability by 3.5% (as assessed by the Oswestry Disability Index, 95% CI, 0.5% to 6.5%), increases early postsurgical pain (odds ratio, 1.78 [CI, 1.06 to 2.95]), and does not significantly affect long-term pain outcomes. Cancer was more common after rhBMP-2 (relative risk, 1.98 [CI, 0.86 to 4.54]), but the small number of events limit making definite conclusions. The benefit of small improvements in fusion should be weighed against more frequent pain in the immediate postoperative period and, possibly, an increased number of cancer cases.