Increased Swelling Complications Associated With Off-Label Usage of rhBMP-2 in the Anterior Cervical Spine

Abstract

In Brief Study Design/Setting. Independent, retrospective clinical record review with a concurrent control. Objective. To identify whether rhBMP-2 is associated with an increased incidence of clinically relevant postoperative prevertebral swelling problems in patients undergoing anterior cervical fusions. Summary of Background Data. Bone Morphogenetic Protein-2 (rhBMP-2) is FDA approved as a bone graft substitute in anterior lumbar interbody fusions. rhBMP-2 has also been used “off-label” in anterior cervical fusions. We suspected that rhBMP-2 might increase the incidence of adverse swelling events. Methods. A total of 234 consecutive patients (ages 12–82 years) undergoing anterior cervical fusion with and without rhBMP-2 over a 2-year period at one institution comprised the study population. The incidence of clinically relevant prevertebral swelling was calculated. The populations were compared and statistical significance was determined. Results. A total of 234 patients met the study criteria, 69 of whom underwent anterior cervical spine fusions using rhBMP-2; 27.5% of those patients in the rhBMP-2 group had a clinically significant swelling event versus only 3.6% of patients in the non-rhBMP-2 group. This difference was statistically significant (P < 0.0001) and remained so after controlling for other significant predictors of swelling. Conclusions. Off-label use of rhBMP-2 in the anterior cervical spine is associated with an increased rate of clinically relevant swelling events. A total of 234 consecutive patients undergoing anterior cervical fusion with and without rhBMP-2 were studied. 27.5% of patients in the rhBMP-2 group had a clinically significant swelling event versus 3.6% in the control group with an odds ratio of 10.1 (P < 0.0001). The difference remained significant after controlling for other predictors of swelling.