Bone morphogenic protein effective in lumbar fusion.

PHILADELPHIA -- Recombinant human-bone morphogenic protein-2 was more effective than an autologous iliac crest bone graft for facilitating lumbar fusion in a randomized study with 47 patients.

The study results showed "several improvements in lumbar fusion procedures provided by the use of rhBMP-2 as a replacement for an autologous iliac crest bone graft," J. Kenneth Burkus, M.D., and his associates said in a poster at the annual meeting of the North American Spine Society.

The study was sponsored by Medtronic Sofamor Danek. Dr. Burkus is a consultant to the company, which makes rhMBP-2 under the trade name Infuse Bone Graft. This material has not received approval from the Food and Drug Administration.

The study enrolled patients who had symptomatic, single-level lumbar spondylosis. The patients underwent anterior lumbar discectomy and interbody fusion using threaded, cortical allografts. The surgeries were done at one of five participating centers.

The patients were randomized, with 23 treated with an autologous, iliac-crest bone graft and 24 treated with rhBMP-2 on a collagen sponge carrier. The demographic profile and the medical histories of patients in the two groups were similar.

After 48 months of follow-up, patients treated with rhBMP-2 consistently had better clinical outcomes than the control patients.

The Oswestry low back pain disability questionnaire score improved by an average of 23.9 points among patients in the rhBMP-2 group, compared with an average drop of 18.5 points among the control patients, reported Dr. Burkus, an orthopedic surgeon at the Hughston Clinic in Columbus, Ga.

The physical component score of the short form (SF)-36 improved by a mean of 10.3 points among patients treated with rhBMP-2 and by 4.4 points in those who received an iliac-crest graft.

After 48 months, 78% of patients in the rhBMP-2 group were working, compared with 41% in the control group. And 94% of patients in the rhBMP-2 group showed evidence of lumbar interbody fusion after 48 months, compared with 71% of the control patients.

None of the patients needed a decompression or stabilization procedure on an adjacent level, and there was no clinical or radiologic evidence that any patient had degeneration in a segment adjacent to the one that was fused. One patient in the rhBMP-2 group needed an additional, posterior stabilization procedure.

BY MITCHEL L. ZOLER

Philadelphia Bureau