SPINAL OSTEOSYNTHESIS INSTRUMENTATION

摘要

Spinal osteosynthesis instrumentation comprising at least one elongate vertebral plate (1, 2), at least one bone screw (7, 8) including a threaded shank (8, 9) and an opposite threaded end portion (16, 17) sized to be inserted through a longitudinal oblong opening (3) in the plate (1, 2), and means for locking the screw (7, 8) relative to the plate in a particular longitudinal position and at a particular angular orientation. The instrumentation comprises at least one shoe (22, 23) mounted to slide on slides (24, 25) formed on one face of the plate (1, 2) and being positively retained thereon. Each shoe (22, 23) has an opening (28, 29) through which passes the threaded end portion (16, 17) of the screw (7, 8). The threaded end portion (16, 17) is adapted to receive a locking nut (21). Each shoe (22, 23) has a spherical bearing surface (31, 32) corresponding to a spherical bearing surface of the locking nut (21) for locking the screw (7, 8) in the chosen angular orientation relative to the plate (1, 2). A large range of angular movement of the screw (7, 8) is thereby allowed relative to the plate (1, 2). The screw is fixed in a particular longitudinal position and at a particular angular orientation by tightening the nut (21) against the shoe (22, 23).