A database and literature review with meta-analysis of 18 studies from seven countries indicates that lumbar fusion outcomes at 24 to 48 months after surgery are not significantly improved by the use of bone morphogenetic protein (BMP).

The results were presented by Evalina Burger, MD, and colleagues at the 2012 AAOS Annual Meeting in their poster, “Two-Year Bone Morphogenetic Protein Clinical Effects after Lumbar Fusion in Degenerative Disc Disease.”

The review covered 14 randomized controlled trials, 3 cohort studies, and 1 retrospective case series, all published in English between 2000 and 2010. Inclusion criteria were as follows:

• patients older than age 18
• lumbar degenerative disk disease with or without stenosis
• grade I to grade II degenerative spondylolisthesis, disk herniation, and other disk pathology
• use of the Oswestry disability index, visual analog scale for back or leg pain, and Short Form-36 questionnaire
• minimum of 24 months of follow-up for clinical outcomes and fusion rate
• postoperative complication rates for not less than 2 years
• employment rate before and 2 years after surgery

Not covered by the review were studies on scoliosis, trauma, isthmic spondylolisthesis, severe (grade III–IV) degenerative spondylolisthesis, tumors, or radiculopathy.

Pooled data showed significant improvements in disability, pain, and physical health status after lumbar fusion, regardless of whether or not BMP was used. Fusion rates were relatively high and approximately similar for both BMP and non-BMP groups. Employment rate did not improve after surgery in either group, and BMP was not associated with an increased complication rate. The risk of publication bias was not significant (P < 0.001).

The authors note that randomized controlled trials assessing outcomes at 12 months have detected superior results in patients receiving BMP, especially patients with spondylolisthesis. They conclude that the results of their longer-term analysis “suggest that the potential benefits of BMP are limited to the early stages of fusion.”

The other authors of the study are Vikas V. Patel, MD, (Aesculap/B. Braun, Biomet, Synthes, Lanx, Baxter, Medtronic, Cerapedics, Vertiflex, OREF, Orthopedics, North American Spine Society, Scoliosis Research Society, Arbeitsgemeinschaft fuer Osteosynthesewesen), and Andriy Noshchenko, MD, PhD (no conflicts). Dr. Burger reports ties to Orthopedics, Springer, Journal of Biomaterials, Journal of Patient Safety, The International Journal of Spine Surgery.

Terry Stanton is the senior science writer for AAOS Now. He can be reached at tstanton@aaos.org

Bottom Line

• A data base and literature review of 18 studies from seven countries focused on outcomes after lumbar fusion spine surgery.
• Researchers found that the use of bone morphogenetic protein (BMP) did not significantly improve results at 2 to 4 years after surgery.
• Because other studies focused on short-term outcomes have found superior results with the use of BMP, the authors suggest that potential benefits of BMP are limited to the early stages of fusion.

Additional Resources
Two Year Bone Morphogenetic Protein (BMP) Clinical Effects after Lumbar Fusion in Degenerative Disc Disease (DDD)