An Artificial Disc Replacement (ADR) includes a body and/or outer wall that is fortified, reinforced, stiffened or otherwise strengthened with a higher durometer, for example, where it rests against a weakened or deficient area of the annulus fibrosis (AF). The "less stiff" portions facilitate the transfer of load to the healthier portion of the AF. A hydrogel or other compressible and/or resilient material may be used within the center of the ADR to selectively transfer the forces to the outer wall. The outer wall may constructed of an elastomer, and may include a radial ply, bias ply, and/or belted construction. Methods of determining a properly sized ADR are also disclosed.
REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent application Ser. No. 10/303,385, filed Nov. 25, 2002; which is a continuation-in-part of U.S. patent application Ser. No. 10/191,639, filed Jul. 9, 2002 and Ser. No. 09/415,382, filed Oct. 8, 1999, now U.S. Pat. No. 6,419,704. The entire content of each application and patent is incorporated herein by reference.
