Patent ID: 8262731
Filing Date: 2012-09-11
Classification: A61F,Y10S

Abstract:
1. An artificial disc device for being implanted entirely within an annulus between endplates of the upper and lower vertebrae, the artificial disc device comprising: upper and lower bearing members each having integral one-piece bodies sized to fit entirely within the annulus, the one-piece bodies having inner facing surfaces and respective smooth outer bearing surfaces comprising a polymer that are entirely free from bone engaging teeth or surface roughening and generally extending in a radial direction for projecting along and slidingly engaging against respective surfaces of the endplates of the upper and lower vertebrae; shifting interfaces between the smooth outer bearing surfaces of the one-piece bodies of the upper and lower bearing members and the respective surfaces of the upper and lower vertebrae; a rigid central bearing portion comprising rigid upper and lower inner arcuate surface portions in engagement with one another with at least one of the inner arcuate surface portions being formed integrally on the inner facing surface of one of the one-piece bodies of the upper and lower bearing members for providing a shifting interface therebetween, wherein the inner arcuate surface portions each have a generally spherical contour with a generally constant radius of curvature from a reference center point and being sized for allowing polyaxial movement between the upper and lower bearing members, and the one-piece bodies of the bearing members being configured so that the engaged, spherical arcuate surface portions provide for substantially 360 degree unrestricted twisting rotational movement between the upper and lower bearing members about a centrally disposed vertical axis extending transverse to the radial direction; opposite radially outer portions of the one-piece bodies of the bearing members each having a substantially semi-circular outer edge in a plane transverse to the vertical axis and sized and configured to fit within the annulus and that are configured to be shifted for substantially 360 degrees from an aligned position with the opposite radially outer portions of each of the one-piece bodies of the bearing members overlapping each other, to offset positions with the opposite radially outer portions offset from each other, and back to the aligned position via the twisting rotational movement between the bearing members to turn the opposite radially outer portions thereof to rotate about the vertical axis; and peripheries extending about each of the one-piece bodies of the bearing members configured so that the one-piece bodies of the bearing members generally have a geometric center thereof with the generally spherical, inner arcuate surface portions arranged so that with the one-piece bodies of the bearing members each extending generally parallel to one another, the geometric centers of the one-piece bodies of the bearing members are aligned, so that the vertical axis extends through the geometric centers of the one-piece bodies of the bearing members and the reference center points of the inner arcuate surface portions.