| 摘要 |
<p>A spinal fusion implant (1) comprises a first and second body member (2, 3) having perforated vertebra-engaging surfaces. The members define a cylindrical body with a rounded end in the collapsed condition. An axially extending threaded activating member (13) within the body is rotated by means of an elongate tool (28) to move the members apart by means of linkages (22). The linkages carry bone engaging elements (27) which are contained within the body in the collapsed condition but which are driven to protrude through apertures (11a - 11c) in the first vertebra-engaging surfaces as the implant reaches its fully expanded condition. The linkages (22) are such that the degree of expansion at the rounded end exceeds that at the other end, to account for the lordotic curve of the patient's spine. The rate of expansion of the implant per evolution of the activating member (13) reduces as the implant reaches its fully expanded condition.</p> |
