A study, presented as a poster at the American Academy of Orthopaedic Surgeons (AAOS) annual meeting (7-11 February 2012, San Francisco, USA), indicates that the use of bone morphogenetic protein (BMP) for lumbar fusion in degenerative disc disease does not significantly improve the rate of fusion in the long term
While BMP has been found to significantly improve lumbar fusion rates at 12 months, it is also been associated with higher complication rates. The aim of the poster study was to review the long-term effects of BMP. Evalina Burger, vice chair and associate professor, Department of Orthopaedics, University of Colorado, Denver, USA, and colleagues performed a retrospective review of 18 studies (14 randomised controlled trials, three cohort studies, and one retrospective case series) that had least 24 months’ worth of follow-up data and had data on the rate of fusion.
They found that the rate of fusion was high in both the BMP groups and the non-BMP groups, and that the rate of fusion in the BMP groups was not significantly higher than the rate of fusion in the non-BMP groups. For example, the fusion treatment effect was 0.93 in the BMP groups and was 0.86 in the non-BMP groups (p=0.125). Also regardless of whether BMP was used or not, according to pooled data, all patients had significant improvements in disability, pain, and physical health status. However, the rate of employment did not significantly improve in either the BMP group or the non-BMP group (treatment effect 1.10, p=0.320; 1.09, p=0.150, respectively) and there were no significant differences in the rates of complications between the groups (treatment effect 0.15 vs. 0.18, respectively; p=0.536).
Burger et al concluded: “Fusion outcomes at 24–48 months postoperative for lumbar degenerative disc disease are not significantly improved by the use of BMP. This result suggests that the potential benefits of BMP are limited to the early stages of fusion.” Burger told Spinal News International: “The meta-analysis did not take the morbidity of bone grafting into account, so we still think it is very reasonable to use BMP as it diminishes hospital stay and lowers infection rates form graft sites. All of these factors are important, but they were not highlighted in our poster study.”