Implantable bone distraction device

摘要

An implantable bone distraction device for inducing controlled lengthening of at an osteotomy site. The device has two elongated plates which are operatively positioned to be substantially parallel and to overlap partially. Each of the plates includes a portion adapted for affixing the plates to respective bone segments. The first plate includes a plurality of parallel sawtooth ridges extending transverse from the long axis of the plate. The second plate includes at least one resilient pawl and at least one resilient ratchet arm. The pawl and arm are engageable with the ridges on the first plate. The ratchet arm responds to application of force on it by engaging with one of the ridges on the first plate and pushing the first plate away from the second plate in the direction of their common axes. The first bone segment is thus moved away from the second bone segment in the direction of the common axes of the plates in a controlled fashion. Backward movement of the first plate toward the second plate is prevented by the abutting engagement of the pawl with one of the ridges on the first plate.