| 摘要 |
<p>A prosthetic intervertebral disc includes an upper plate and a lower plate and employs congruent stepped features to provide limited articulating motion between the plates. The stepped features can be used to provide articulating motion of a rocking type rather than a rubbing or translating type of motion provided in many artificial discs. Each of two parts of the intervertebral disc includes two or more stepped bearing surfaces, having curved or flat shapes, which mate with one another to provide the articulation to the disc. The stepped features can be designed to restrict motion in flexion-extension or lateral bending to less than a predetermined angle. The stepped design can be modified to either allow or prevent rotational motion between the plates. The limited motion disc substantially prevents translation, however some limited translation can be provided by modification of the relative sizes of the stepped features.</p> |
