| 摘要 |
This invention is an implantable bone distraction device for inducing controlled lengthening of bones at an osteotomy site. The device has two elongated plates (12, 14) which are operatively positioned to be substantially parallel and to overlap partially. Each of the plates (12, 14) includes a portion (24, 34) for affixing the plates to respective bone segments (13, 15). The first plate (12) includes a plurality of parallel sawtooth ridges (36) extending transverse from the long axis (A) of the plate (12). The second plate (14) includes at least one resilient pawl (40) and at least one resilient ratchet arm (44). The pawl (40) and the arm (44) are engageable with the ridges (36) on the first plate (12). The ratchet arm (44) responds to application of force on it by engaging with one of the ridges (36) on the first plate (12) and pushing the first plate (12) away from the second plate (14) in the direction of their common axes (A, B). The first bone segment (13) is thus moved away from the second bone segment (15) in the direction of the common axes (A, B) of the plates (12, 14) in a controlled fashion. Backward movement of the first plate (12) toward the second plate (14) is prevented by abutting engagement of the pawl (40) with one of the ridges (36) on the first plate (12).
|
