Safety, efficacy, and dosing of recombinant human bone morphogenetic protein-2 for posterior cervical and cervicothoracic instrumented fusion with a minimum 2-year follow-up.

BACKGROUND: Considerable attention has focused on concerns of increased complications with recombinant human bone morphogenetic protein-2 (rhBMP-2) use for anterior cervical fusion, but few reports have assessed its use for posterior cervical fusions.
OBJECTIVE: To assess the safety, efficacy, and dosing of rhBMP-2 as an adjunct for instrumented posterior cervical arthrodesis.
METHODS: All patients treated by the senior author with posterior cervical or cervicothoracic instrumented fusion using rhBMP-2 from 2003 to 2008 with a minimum of 2 years of follow-up were included. Diagnosis, levels fused, rhBMP-2 dose, complications, and fusion were assessed.
RESULTS: Fifty-three patients with a mean age of 55.7 years (range, 2-89 years) and an average follow-up of 40 months (range, 25-80 months) met inclusion criteria. Surgical indications included basilar invagination (n = 6), fracture (n = 6), atlantoaxial instability (n = 16), kyphosis/kyphoscoliosis (n = 22), osteomyelitis (n = 1), spondylolisthesis (n = 1), and cyst (n = 1). Fifteen patients had confirmed rheumatoid disease. The average rhBMP-2 dose was 1.8 mg per level, with a total of 282 levels treated (average, 5.3 levels; SD, 2.8 levels). Among 53 patients, only 2 complications (3.8%) were identified: a superficial wound infection and an adjacent-level degeneration. No cases of dysphagia or neck swelling requiring treatment were identified. At the last follow-up, all patients had achieved fusion.
CONCLUSION: Despite many of the patients in the present series having complex pathology and/or rheumatoid arthritis, a 100% fusion rate was achieved. Collectively, these data suggest that use of rhBMP-2 as an adjunct for posterior cervical fusion is safe and effective at an average dose of 1.8 mg per level.