Biologic enhancement of spinal fusion with bone morphogenetic proteins: current position based on clinical evidence and future perspective

Spinal fusion may be indicated for spinal instability and/or deformity. Advancements in spinal fusion have significantly increased the fusion rate. However, the validated biomechanical properties of modern instrumentation cannot attain 100% fusion because induction of heterotopic bone formation requires a complex balance of biologic factors and operative techniques. Currently, iliac crest autologous bone grafting (ICBG) is the gold standard to enhance biologic spinal fusion. Autogenous bone has osteogenic, osteoinductive, and osteoconductive abilities. However, ICBG is associated with several disadvantages, including increased procedure time, limited donor-site availability, and donor-site pain, with rates that vary significantly in the literature.