Effectiveness and safety of recombinant human bone morphogenetic protein-2 versus local bone graft in primary lumbar interbody fusions

Study Design: Retrospective cohort study.

Objective: To compare clinical outcomes, fusion rates, and rates of complications in posterior lumbar interbody fusions (PLIFs) and transforaminal lumbar interbody fusion procedures with either recombinant human bone morphogenetic protein-2 (rhBMP-2) and local bone graft (LBG) or LBG alone used as graft material.

Summary of Background Data: rhBMP-2 is often used in PLIF and transforaminal lumbar interbody fusion procedures, but is associated with complications. Furthermore, recent evidence suggests that using LBG may be sufficient to induce fusion.

Methods: All patients who underwent primary interbody fusions under a single surgeon were identified from the surgeon's records. In November 2008, the surgeon changed from routinely using LBG to using LBG and rhBMP-2 routinely, limiting selection bias. A retrospective review of prospectively collected data preoperatively and up to 12 months postoperatively was performed. Data collected included visual analogue scale, pain scores for back and leg, Oswestry Disability Index scores, Short-Form 36 (SF-36), standing lumbar radiographs, and clinical notes.

Results: Seventy-seven patients met the study criteria and 70 consented to be part of the study. Fifty-one were treated with rhBMP-2 and 19 with LBG. At 12-month follow-up, no significant differences were seen in visual analogue scale score, Oswestry Disability Index score, or SF-36 scores. A total of 89.5% of the LBG group and 94.1% of the rhBMP-2 group went on to show radiographical evidence of fusion by 12-month follow-up (P = 0.61). The rhMBP-2 group had a higher complication rate (41.2% vs. 10.5%, incidence rate ratio = 3.91, P = 0.05).

Conclusion: In comparison we found no difference in clinical outcomes, comparable rates of fusion and a significant increase in complication rates with rhBMP-2. Using rhBMP-2 may unnecessarily increase the risk of complication in routine PLIF and transforaminal lumbar interbody fusion procedures.