Artificial disc prosthesis: design concepts and criteria.

Clinical and biomechanical objectives of disc arthroplasty are reviewed in this paper. The available literature relative to these criteria for nucleus and total disc replacement where relevant is also reviewed. Clinical criteria include: pain relief, functional recovery, lower morbidity than spinal fusion, shorter recuperation, and ease of implantation and revision. Biomechanical criteria include: preservation of motion in compression-bending and compression-torsion, shock absorption, relief of abnormal stresses within and adjacent to the motion segment, stability, and alignment. A review of devices with these criteria in mind is reported.