Study Design. Multicenter randomized controlled trial.
Objective. To evaluate the effect of recombinant human bone morphogenetic protein (rhBMP-2) on radiographical fusion rate and clinical outcome for surgical lumbar arthrodesis compared with iliac crest autograft.
Summary of Background Data. In many types of spinal surgery, radiographical fusion is a primary outcome equally important to clinical improvement, ensuring long-term stability and axial support. Biologic induction of bone growth has become a commonly used adjunct in obtaining this objective. We undertook this study to objectify the efficacy of rhBMP-2 compared with traditional iliac crest autograft in instrumented posterolateral lumbar fusion.
Methods. Patients undergoing 1- or 2-level instrumented posterolateral lumbar fusion were randomized to receive either autograft or rhBMP-2 for their fusion construct. Clinical and radiographical outcome measures were followed for 2 to 4 years postoperatively.
Results. One hundred ninety seven patients were successfully randomized among the 8 participating institutions. Adverse events attributable to the study drug were not significantly different compared with controls. However, the control group experienced significantly more graft-site complications as might be expected. 36-Item Short Form Health Survey, Oswestry Disability Index, and leg/back pain scores were comparable between the 2 groups. After 4 years of follow-up, radiographical fusion rates remained significantly higher in patients treated with rhBMP-2 (94%) than those who received autograft (69%) (P = 0.007).
Conclusion. The use of rhBMP-2 for instrumented posterolateral lumbar surgery significantly improves the chances of radiographical fusion compared with the use of autograft. However, there is no associated improvement in clinical outcome within a 4-year follow-up period. These results suggest that use of rhBMP-2 should be considered in cases where lumbar arthrodesis is of primary concern.
Level of Evidence: N/A
Eight participating institutions randomized 197 patients undergoing instrumented lumbar fusion to compare recombinant human bone morphogenetic protein (rhBMP-2) with iliac crest autograft. SF-36, Oswestry Disability Index, and leg/back pain scores were comparable between groups. Radiographical fusion rates were significantly higher in patients treated with rhBMP-2 (94%) than those who received autograft (69%) (P = 0.007; 48 mo).
*University of Calgary Spine Program and Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta
†Division of Orthopedic Surgery, Dalhousie University, Halifax, Nova Scotia, Canada
‡Division of Orthopedic Surgery, University of Western Ontario, London, Ontario, Canada
§Division of Orthopedic Surgery, University of Alberta, Edmonton, Alberta, Canada
¶Division of Orthopedic Surgery, Dalhousie University, St. John, New Brunswick, Canada
‖Division of Orthopedic Surgery, Trillium Health Centre, Mississauga, Ontario, Canada;
**Division of Orthopedic Surgery, University of Montreal, Montreal, Quebec, Canada; and
††Division of Orthopedic Surgery, University of British Columbia, Vancouver, British Columbia, Canada.
Address correspondence and reprint requests to R. John Hurlbert, MD, PhD, FRCSC, FACS, Department of Clinical Neurosciences, Foothills Hospital, 1403 29th St N.W. Calgary, Alberta, Canada T2N 2T9; E-mail: firstname.lastname@example.org
Acknowledgment date: July 8, 2011. First revision date: February 18, 2012. Second revision date: July 28, 2012. Third revision date: November 2, 2012. Fourth revision date: April 12, 2013. Fifth revision date: August 28, 2013. Acceptance date: August 29, 2013.
rhBMP-2 is not FDA-approved for this indication.
Medtronic Inc. funds were received to support this work.
Relevant financial activities outside the submitted work: consultancy.