Introduction: Pseudoarthrosis in spine surgery is a major cause of patient morbidity, causing post-operative chronic pain and requiring further surgery. Biologic agents hav demonstrated improved rates of successful arthrodesis. rhBMP-2 (BMP) is FDA-approved for anterior lumbar surgery but used off-label in other settings. In this study, the authors review their experience with BMP in anterior cervical surgery patients at high risk for pseudoarthrosis.
Methods: All patients undergoing anterior cervical fusions with discectomy or corpectomy by the senior authors from Jan 2005-June 2014 were retrospectively reviewed. Operative notes were used to determine use of BMP. Patients received polyetherether ketone cages or allograft with BMP-impregnated collagen sponge. Fusion status at last follow-up was determined. Arthrodesis was defined as clear bone growth on radiograph or CT scan without movement of the fused segment on dynamic imaging. Statistical analysis was performed on Microsoft Excel and GraphPad.
Results: Three hundred forty-four records were reviewed; 63 patients representing 139 levels received BMP with a mean dose of 0.62mg/level. At mean follow-up of 12.2±14.6 months, 84.1% had solid arthrodesis. Discectomy patients fused more frequently than corpectomy patients (93.2%, 63.2% respectively, p=0.0058). Non-smokers did not fuse significantly more often than smokers (87.0%, 76.4% respectively, p=0.4376). Two patients required reoperation within 30 days (1 seroma, 1 hematoma), 8 patients had dysphagia, and 3 had postoperative swelling requiring steroids. One patient had persistent hoarseness. Twelve patients (19.0%) developed adjacent segment degeneration. One patient developed heterotopic ossification.
Conclusions: The authors utilized BMP to enhance arthrodesis in a high-risk cohort of patients undergoing anterior cervical surgery. Our fusion rate compares favorably with historical controls and the complication rate is acceptably low using smaller doses of BMP than previously reported. One patient required reoperation for BMP-related complication. BMP can be safely implanted in the anterior cervical spine and enhances fusion in high-risk patients.
Patient Care: More widespread use of BMP in anterior cervical fusions in high-risk patients will reduce pseudoarthrosis rates and potentially prevent reoperations.
Learning Objectives: In a high-risk population of patients undergoing spinal fusions, pseudoarthrosis rates are higher than the baseline population. The study indicates the safety of BMP and efficacy to prevent pseudoarthrosis in such a population.