| 摘要 |
A motion restoring intervertebral prosthesis for replacing a failed or partially failed natural disc comprises two components defining an imaginary longitudinal axis generally aligned with the spinal axis when installed, the components having vertebral body engaging surfaces on one side and mating articulating surfaces on the other side, with peripheral rims encircling the articulating surfaces. The articulating surfaces accommodate rotational motion about the longitudinal axis and limited pivotal motion about the A/P and M/L planes. The rims are arranged to contact and limit the pivotal motion between the components to about +/-6° and preferably +/-4° in both directions in the M/L plane and in the A/P plane in the forward direction. Optionally, the encircling rims allow pivotal action of about 20° to 30° in the A/P plane in the rearward direction.
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