Fusion rates in multilevel, instrumented anterior cervical fusion for degenerative disease with and without the use of bone morphogenetic protein

Object. The goal of this study was to compare the rates of solid arthrodesis and complications following multilevel, instrumented anterior cervical fusion in patients treated with and without bone morphogenetic protein (BMP). Methods. The authors conducted a retrospective cohort study of patients who underwent multilevel (2+ level) anterior cervical fusions performed for degenerative disc disease with or without the concurrent use of BMP-2 from 1997 to 2012. The dosage throughout the study ranged from 2.1 to 0.26 mg/level (mean 1.0 mg/level). All patients were evaluated postoperatively by means of radiographs and CT scans to determine fusion status. Results. The overall fusion rate for the patients treated without BMP (n = 23) was 82.6% compared with a 100% fusion rate in the group treated with BMP (n = 22) (p = 0.04). The pseudarthrosis rates increased with number of fusion levels in patients who did not receive BMP, whereas all patients in the group treated with BMP had solid arthrodesis. Furthermore, there were 2 instrumentation failures in the non-BMP group. There was a direct correlation between the incidence of complications and the dosage of BMP used per level, with no complications reported at doses equal to or less than 1.1 mg/level. Conclusions. The overall rate of bony arthrodesis was increased following the use of BMP in multilevel anterior cervical fusion. Traditional methods without BMP had a high rate of pseudarthrosis. The complications associated with the use of BMP appeared to be dose related and of low incidence when BMP is used in doses equal to or less than 1.1 mg/level. (http://thejns.org/doi/abs/10.3171/2012.12.SPINE12607)