| abstract |
The present invention is directed to intervertebral prosthetic devices and methods. The intervertebral prosthetic devices and methods of the invention provides a variable instantaneous axis of rotation. In general, the disclosed devices include two bearing surfaces, a first bearing surface being curved and a second bearing surface being planar. In some embodiments, the curved bearing surface provides at least three degrees of rotational freedom and the planar bearing surface provides at least two degrees of translational freedom and one degree of rotational freedom. Several embodiments with varying degrees of rotational or translational freedom are disclosed. |