[Experimental spinal fusion in a rabbit model with new drug delivery system for BMP]

Bone morphogenic protein (BMP) is a powerful bone-inducing cytokine and has been used as a new bone graft substitute with bovine-derived collagen sponge as a delivery system. Excellent clinical results have been reported with use of these BMP-retaining implants. However, certain problems remain with use of them, such as the need for high doses of BMP to obtain new bone formation, resulting in high cost, and the potential risks for disease transmission (e.g., variant Creutzfeldt-Jacob disease). To avoid use of collagen, we have developed a synthetic polymer/beta-Tricalcium Phosphate composite as a new delivery system for BMP. This new material, when used in combination with low doses of BMP-2, consistently elicited new bone and was successfully used to achieve posterolateral spinal fusion in a rabbit model.