There are three challenges in the research and development of artificial spinal discs: replication of the biomechanics of the natural human disc, long-term stability including fatigue life, and fixation between implants and vertebral bodies. Foster-Miller, Inc. proposes to develop a biomimetic spinal disc prosthesis which has high potential to overcome all three challenges. The Foster-Miller prosthesis consists of a nucleus core, a fiber-reinforced annulus ring, and fiber-reinforced endplates. The gelatinous core and elastomeric ring mimic the nucleus pulposus and annulus fibrosus of the human disc respectively. Fibers in the annulus ring and endplates are woven together to form an integral fibrous preform. A braided structure is utilized in order to better replicate the mechanical behavior of the natural disc, and to increase the strength and fatigue resistance of the prosthesis. While the same polyurethane is selected for the nucleus core and annulus ring matrix, a much stiffer polycarbonate is chosen for the endplate matrix. The polyurethane and polycarbonate can be chemically bonded together to form an integral structure during fabrication. Samples will be made using an approach involving an innovative braiding process and continuous matrix casting to ensure structural integrity. The overall goal of this Phase I research is to demonstrate the feasibility of the proposed prosthesis by investigating its mechanical behavior, effects of repetitive loads on its structural integrity and debris generation. Successful completion of the proposed Phase I program will provide a solid foundation for a Phase II research, which will be undertaken to investigate fixation efficacy of the Foster-Miller spinal disc prosthesis. ? ? ?
