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...http://www.google.fr/patents/US7727266?utm_source=gb-gplus-shareBrevet US7727266 - Method and apparatus for retaining screws in a plate
Method and apparatus for retaining screws in a plate
