BMP vs Autograft for Instrumented Posterolateral Lumbar Fusion
In diligent efforts to improve osseous bridges when performing spinal fusion surgery, orthopaedists have been using harvested allograft bone for more than a century and bone morphogenetic protein (BMP) for nearly a half century. Now, a European multicenter, randomized trial by Delawi et al., in the March 16, 2016 Journal of Bone & Joint Surgery, has compared overall success (defined as a combination of CT-determined fusion rates and clinical results at 12 months) between the two approaches among 113 patients.
This was a non-inferiority trial, and the BMP formulation used (Osigraft BMP-7, known commonly as OP-1 and available in the US in a similar formulation known as OP-1 Putty) was not non-inferior to iliac crest autograft. To clarify the potentially confusing double negative: OP-1 was less successful than autograft, due primarily to lower fusion rates. There were no significant between-group differences in clinical outcomes as measured by scores on the Oswestry Disability Index, although the authors added that “our follow-up period of one year may have been too short to show differences in clinical results.”
Delawi et al. conclude that, based on their findings, “use of OP-1 in place of autologous iliac crest bone graft in instrumented posterolateral lumbar fusions cannot be recommended.” That conclusion is echoed by commentator Jeffrey Coe, MD, who sees these findings as “another bit of evidence against the use of rhBMP-7 as a substitute for [iliac crest bone grafts] in posterolateral spinal fusion.”