Patent attributes
Bone plate systems and retainers are provided for surgical implants and bone repair. The bone plate is multi-tiered for receiving bone anchors or screws for securing multiple bones or bone fragments in a desired relationship. The plate includes bores for receiving the screws, and the bores may permit and define a translation path for the screws relative to the plate. The retainers are held in a recess in the bores to prevent screw back-out. Once the screw is seated with the plate, the retainer rests over a top surface of the screw to impede screw back-out from the plate. The retainer may expand to permit driving a screw therethrough and may contract once the screw is seated within the plate so the retainer is in a configuration for preventing back-out. Tools and methods are also provided for implantation and removal of the plates and the screws.