Bone Graft Substitute Causes Swelling in Anterior Neck Fusion

Growth factors contained in bone called bone morphogenetic protein (BMP) are now being used to stimulate bone healing. One BMP (rhBMP-2) has been approved by the FDA for use in anterior lumbar spine fusion. It has also been used for similar fusions of the anterior (neck) cervical spine.

Since rhBMP-2 wasn't tested and approved for use in the cervical spine, this use is called off-label. The off-label use of rhBMP-2 in anterior spinal fusions has some problems.

In a recent study from the University of Iowa and Spine Center at Emory University, patients getting rhBMP-2 had 10 times the amount of neck swelling after the operation. The surgeons report this wasn't the usual mild swelling that occurs right after the surgery.

Most patients had a delayed reaction (by several days). The swelling was so severe they had trouble breathing and swallowing. The surgeons aren't sure why this happened. It could be the amount of rhBMP-2 used. Or perhaps it's the way it is placed at the fusion site.

By comparing two groups of patients (with and without rhBMP-2) they were able to show this reaction was more common in patients over age 50 years who had several segments fused at the same time. Further analysis didn't support these factors as being significant.

For now the authors agree that off-label use of rhBMP-2 for anterior cervical spine fusions should be used with caution. Prophylactic steroids are given to patients receiving rhBMP-2 after surgery. The manufacturer of this product put out a safety alert in 2004 saying that local soft tissue swelling could occur with off-label use. Further study is needed to find out which patients can benefit from this bone enhancing tool without the serious side effects.



References: Joseph D. Smucker, MD, et al. Increased Swelling Complications Associated with Off-Label Usage of rhBMP-2 in the Anterior Cervical Spine. In Spine. November 15, 2006. Vol. 31. No. 24. Pp. 2813-2819.