| 摘要 |
<p>A variable height, multi-axial bone screw assembly including a bone screw, a collet, a tulip shaped connector, a crown member, a rod and a set-screw, The bone screw has threads at its lower end and a generally cylindrical shaft at its upper end. The collet has a cylindrically shaped lower end to hold and grasp the bone screw shaft as well as a generally bulb shaped upper end to be received by the tulip shaped connector. By changing the position of the bone screw shaft grasped by the collet, the height of the bone screw vis-à-vis the tulip shaped connector can be varied. All the elements of the bone screw assembly are combined together by placing the collet head, crown member and rod within a central bore of the connector and firmly tightening them in place using the set screw.</p> |
