Screw retaining system in vertebral plate, has ring which is resilient and changes shape between original shape that extends over aperture and deflected shape away from aperture to allow insertion and removal of screw from aperture.
Abstract:
A retention system for maintaining a screw to a vertebral plate. One or more screws extend through apertures within the vertebral plate. A cavity is positioned adjacent to and overlaps into the aperture. A ring is positioned within the cavity and held in position by a cap. The cap attaches to the plate to prevent removal of the ring. The ring is deflectable between a first shape to allow the screw to be inserted and removed from the aperture, and a second shape to prevent screw back-out from the aperture. A method of using the system is also included and comprises positioning the ring within a cavity in the plate, maintaining the position of the ring to the plate by attaching a cap, inserting a screw through the aperture and attaching the plate to a vertebral member, and positioning the ring over the screw head and preventing the screw from backing-out.
