Patent ID: 7520899

Claim:
An intervertebral implant comprising: a. an articulating unit adapted to be inserted between adjacent vertebral bodies, the articulating unit having an outer perimeter, and having a first arcuate channel therein, the first arcuate channel having ends spaced inwardly from the first outer perimeter; b. a crossbar spacer in contact with the first arcuate channel, wherein the crossbar spacer and the first arcuate channel allow the articulating unit to rotate in association with flexion and extension of at least one of the vertebral bodies, wherein the crossbar spacer includes i. a first spacer beam having a curved outer side surface centered about a first longitudinal axis and having a first end and a second end; and ii. a second spacer beam perpendicular to the first spacer beam having a curved outer side surface centered about a second longitudinal axis, the first spacer beam being disposed relative to the second spacer beam so that the second longitudinal axis is closer to the first end of the first beam than to the second end, the first and second spacer beams each respectively extending beyond opposing sides of each other; and c. a first keel adapted to mate with a vertebral body, the first keel extending from a first outer surface of the articulating unit and oriented to be substantially parallel with the first channel.