Postoperative cervical myelopathy and cord compression associated with the use of recombinant bone morphogenetic protein-2 in posterior cervical decompression, instrumentation, and arthrodesis: a report of two cases.

STUDY DESIGN

Case report.

OBJECTIVE

Two cases are presented in which the use of recombinant bone morphogenetic protein-2 (rh-BMP-2) in a posterior cervical decompression and instrumented arthrodesis may have contributed to seroma formation and cord compression.

SUMMARY OF BACKGROUND DATA

The use of rh-BMP-2 has been proven effective in promoting bone formation in anterior lumbar spine arthrodesis. Whether rh-BMP-2 is safe and/or effective in the cervical spine has not been determined. Adverse effects when it is used for anterior cervical fusion procedures have been reported but its role in posterior cervical decompression and instrumented fusions has yet to be determined.

METHODS

We report on two cases. The first is a 68-year-old man presenting with a substantial decline in his neurologic status approximately 2 weeks after surgery. The second is a 44-year-old man presenting with a substantial decline in his neurologic status approximately 5 days after surgery. Both complications occurred after a posterior cervical laminectomy and instrumented arthrodesis when rh-BMP-2 was used as a bone graft substitute.

RESULTS

Both patients were found to have a moderate-to-large seroma causing severe compression on the spinal cord and were urgently taken to an operating room for evacuation of the seromas. Both showed improvement of their neurologic status immediately after surgery. As rh-BMP-2 is known to occasionally cause seroma formation it is postulated that it may have been the cause of the seromas.

CONCLUSION

Caution should be exercised with rh-BMP-2 use in posterior cervical applications when a laminectomy has been performed. The safe and effective dose and technique for application have yet to be determined. Seroma formation is possible, which can cause acute stenosis with cord compression and neurologic compromise.