Perioperative Complications of Recombinant Human Bone Morphogenetic Protein-2 on an Absorbable Collagen Sponge Versus Iliac Crest Bone Graft for Posterior Cervical Arthrodesis

Study Design. Retrospective evaluation of perioperative complications with recombinant human bone morphogenetic protein-2 on an absorbable collagen sponge (rhBMP-2/ACS) versus iliac crest bone graft (ICBG) for instrumented posterior cervical fusion. Objective. To determine the risk of perioperative complications using rhBMP-2/ACS for posterior cervical fusion compared with ICBG. Summary of Background Data. There is substantial use of rhBMP-2/ACS as a bone graft substitute for spine fusions outside the Food and Drug Administration-approved indication of anterior lumbar interbody fusion. Efficacy for inducing fusion and avoidance of iliac crest donor-site complications are frequent reasons cited for its use. Previous studies have reported use in the anterior lumbar spine, the posterior lumbar spine, and in the anterior cervical spine. Site-specific perioperative complications that have been reported, especially with use in the anterior cervical spine, confirm that safety and efficacy should be established for specific anatomic sites and clinical indications. Methods. From July 2002 to February 2005, a consecutive series of patients who underwent instrumented posterior cervical fusion were identified. Patients received either rhBMP-2/ACS or ICBG based on the discretion of the surgeon. Patients were excluded if they had a preoperative diagnosis of trauma, tumor, or infection, or if they underwent a concomitant anterior procedure. Seventy-seven patients met the inclusion criteria. Forty-one of these patients received rhBMP-2/ACS and 36 received ICBG. Standard demographic, surgical, and perioperative complication data were collected from the medical records. Results. There were no significant differences in age, gender distribution, smoking status, number of surgical levels, blood loss, operative time, or length of stay between the 2 groups. There were more posterior cervical wound complications requiring treatment in the rhBMP-ACS group (6, 14.6%) versus the ICBG group (1, 2.8%), although this was not statistically significant (P = 0.113). One patient (2.8%) in the ICBG group had a wound complication at the iliac crest donor site. Additional perioperative complications were noted in 3 patients (7.3%) in the ICBG group and none in the rhBMP-2/ACS group. Conclusion. The higher incidence of posterior cervical wound complications in the rhBMP-2/ACS group, although not statistically significant, may be related to an inflammatory response to rhBMP-2. This potential risk must be weighed against the elimination of donor-site complications associated with ICBG harvesting, and considered in light of ultimate clinical outcome. Additional studies are needed to clarify this issue, as well as to determine optimal dosing and carrier for usage in the posterior cervical spine.