| 摘要 |
An implantable fixation system comprises at least one bracing member (46), at least one clamp (12), at least one bone anchoring member (2) and at least one retaining member (10) capable of securing the clamp (12) to the bone anchoring member (2). The at least one clamp (12) comprises first and second plates (14, 16) which are mutually hinged at respective first ends (14b, 16b) so as to be pivotable between a clamping and a non-clamping position. A clamping passage (22a; 22b) adapted to receive a region (46a) of the bracing member (46) is defined between facing surfaces (14c, 16c) of the plates (14, 16) when in the clamping position, and each plate (14, 16) has an orifice (26a, 26b) therein which orifices (26a, 26b) are aligned in the clamping position so as to form a continuous passage through the plates (14, 16). The at least one bone anchoring member (2) has a shank (4) for engaging in a bone (40, 42, 44), a post (8) adapted to be received in the continuous passage, and an abutment shoulder (6) intermediate the shank (4) and the post (8). The abutment shoulder (6) and the retaining member (10) each have a part-spherical surface (6b, 10b), said surfaces (6b, 10b) being adapted to mate with correspondingly part-spherical surfaces (28a, 30) on the first plate (14) and the second plate (16) respectively. In the clamping position, when the part-spherical surfaces (28a, 30) of the first and the second plates (14, 16) are in abutment with the part-spherical surfaces (6b, 10b) of the abutment shoulder (6) and retaining member (10) respectively, said part-spherical surfaces (28a, 6b; 30, 10b) have respective centres of curvature which are substantially coincident. |
