Single-lock anterior cervical plate and method
AssigneeWarsaw Orthopedic, Inc.
InventorGary K. Michelson
Life of this patent
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Abstract
Anatomically contoured anterior cervical plates with bone ingrowth surfaces, providing for intersegmental compressive preloading, and a rigid and locked interface to all of the bone screws, with those engaging the vertebrae deployed in highly convergent pairs. The bone screws have a tapered self-tapping leading end, an increasing root diameter with a generally constant outer diameter with a thread that is narrow and sharp throughout and an enlarged head portion capable of an interference fit to the receiving holes of the plate. Instrumentation consists of plate holders, a compression apparatus and a pilot hole forming device that interlocks with the plate. Methods for spinal compression and bone hole preparation are provided.
Claims22
A plate system adapted for application to an anterior human spine and for contacting at least a portion of anterior aspects of at least two vertebral bodies adjacent a disc space, said plate system comprising:
- a plate having a mid-longitudinal axis and a length sufficient to span the disc space and overlap portions of the at least two adjacent vertebral bodies, said plate having a lower surface for placement against the vertebral bodies and an upper surface opposite said lower surface;
- at least two bone screw receiving holes extending through said plate from said upper surface through said lower surface;
- a plurality of bone screws, each bone screw insertable in one of said bone screw receiving holes, each bone screw having a head, a tip opposite said head, and a threaded shaft, said head having a maximum height parallel to the central longitudinal axis of said bone screw and a maximum diameter transverse to the central longitudinal axis of said bone screw, the maximum height of said head being less than one-half the maximum diameter of said head;
- and
- a locking element having a lower-facing surface adapted to cover a portion of said head of only a single one of said bone screws to prevent the inadvertent backing out of said single bone screw from one of said bone screw receiving holes, said locking element having an outer diameter, a central longitudinal axis, and an opening through said locking element along the central longitudinal axis.
A method for connecting at least two vertebral bodies adjacent a disc space from an anterior aspect of the vertebral bodies, said method comprising the steps of:
- providing a plate having a length sufficient to contact the two adjacent vertebral bodies across the disc space and having a plurality of bone screw receiving holes;
- inserting at least in part into the plate a locking element adapted to lock only a single bone screw to the plate, the locking element having a central longitudinal axis;
- positioning the plate against at least a portion of the anterior aspect of the vertebral bodies to align at least one of the bone screw receiving holes with a respective one of the adjacent vertebral bodies;
- and
- inserting a bone screw having a head having an upper facing surface into a position in one of the bone screw receiving holes that permits the locking element to cover a portion of the upper facing surface of the head of the bone screw after the bone screw has been inserted into the plate, the step of inserting the bone screw being performed after the step of inserting the locking element.
Dependencies are inferred from the claim text.