Patent ID: 6491695
Filing Date: 2002-12-10
Classification: A61B

Abstract:
Apparatus for aligning first and second vertebrae which are misaligned and have confronting portions with at least one tapped thread adapted to receive a complementally threaded fusion cage, said apparatus comprising:a partible screw, rotatable in first and second opposite directions about a longitudinal axis, for threadedly coupling to and decoupling from, respectively, said first and second vertebrae; said partible screw including first and second relatively axially moveable screw halves having first and second pluralities of axially spaced, helically extending, partial screw thread sections, respectively which can be helically aligned with each other in any selected one of a plurality of different axially shifted locations to form a helical screw thread complementally formed to, and adapted to be received by, said tapped thread when said screw is turned in said first direction of rotation about said axis; means for relatively axially shifting said first and second screw halves to first positions in which at least a first portion of said first plurality of partial screw thread sections is helically aligned with a first portion of said second plurality of partial screw thread sections when said screw is being rotated in said first direction about its axis and threadedly coupled to said first and second vertebrae, and for relatively axially shifting said first and second screw halves from said first positions to second positions, in which said first portion of said first plurality of partial screw thread sections is helically aligned with a second axially spaced portion of said second plurality of partial screw thread sections, to shift said first vertebrae into alignment with said second vertebrae; and locking means for detachably locking said first and second screw halves together in said second positions to preclude relative axial shifting of said first portion of said first plurality of screw threads section and said second portion of said second plurality of partial screw thread sections as said partible screw is rotated in said second direction and threadedly decoupled from said first and second vertebrae.