Safety and effectiveness of recombinant human bone morphogenetic protein-2 for spinal fusion: a meta-analysis of individual-participant data.
Purpose of Study
In 2011, researchers identified the potential for study bias regarding results of the use of Bone Morphogenic Protein-2 for lumbar spinal fusion. Medtronic, the manufacturer of Infuse BMP-2, consented to have an independent review of their raw data from all FDA rhBMP2 trials. This study was funded and conducted by The Yale University Open Data Project (YODA).
The paper summarized the results of the raw data related to randomized clinical trials (RCTs) using Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2) versus Iliac Crest Bone Graft (ICBG) for lumbar fusions.
Meta-analysis of the data taken from 12 RCTs was examined which included 1408 Individual Participant Data (IPD).
Data was collected in defined intervals up to 24 months post-surgery. Factors including age, sex, smoking history, alcohol consumption, BMI, Diabetes, and prior surgery were collected. Oswestry Disability Index (ODI) and Neck Disability Index (NDI) measures were reviewed. Back and leg pain scores were also included.
After reviewing the data the researchers concluded “At 24 months, rhBMP-2 increases fusion rates, reduces pain by a clinically insignificant amount, and increases early postsurgical pain compared with ICBG. Evidence of increased cancer incidence is inconclusive.”
The authors were academic researchers who methodically analyzed the data and did not provide any editorial comments but rather provided their rationale and specific methodology in an appendix at the end of the paper.
Overall, this was an excellent study, but in terms of potential side effects and long term concerns about the use of BMP-2, 24 months of follow-up data is too short a time period to capture all the potential side effects of BMP. Certainly, there is statistical evidence of increased fusion rate at 2 years which is a reasonable time period to assess fusion status. However, unintended effects such as cancer and heterotopic bone growth may not be captured in this short of a time span. A longer follow-up period of the exposed patients is needed to help clarify the inconclusive results.