Bone graft substitutes: The use of genetically engineered bone morphogenetic proteins for spinal fusion

Purpose of review: Spinal fusion often results in high rates of pseudarthrosis and morbidity related to the harvest of autogenous iliac crest bone graft. For this reason there exists a significant amount of interest in bone graft substitutes and enhancers to improve clinical outcomes for these patients. Among these, bone morphogenetic proteins (BMPs) have been widely investigated in their role as bone graft substitutes to enhance spinal fusion. Recent findings: The characterization of BMPs in animal models has demonstrated great promise in the use of growth factors to induce bone formation. This innovative research has led to recent clinical studies reporting the success of BMPs through a number of surgical approaches. The delivery of BMPs in tissue engineering via gene therapy has provided a means to allow sustained production of growth factor in a biologic environment. Summary: Recent studies involving BMP have paved the way for further use and research involving the enhancement of spinal fusion. Novel therapies such as cell-based treatments, gene transfer strategies, and carrier modifications are all being used to identify the most efficacious way to use BMPs in spine surgery.