Lateral vertebral lumbar plate system with integrated rotational control mechanism for screw retention

Inventors

Thompson, Joseph • Klepa{hacek over (c)}, Gary W.

Assignees

Kyocera Medical Technologies Inc

Abstract

A plate system includes a retention cap and a plate. The retention cap includes a head with tangs and a shank. The shank includes protrusions at an end of the shank and relief cut-outs clocked relative to the protrusions. The plate includes screw holes and a locking feature. The locking feature includes an assembly guide adapted to guide the shank and features thereof into the locking feature, locking detents distal to the top surface of the plate and adapted to receive the protrusions and interfere with rotational movement of the retention cap, and a retainer positioned axially between the assembly guide and the locking detents. The retainer is adapted to prevent axial movement of the retention cap. The locking feature is adapted to hold the retention cap with the tangs overlapping the screw holes and with the tangs not overlapping the screw holes.

Core Innovation

The invention relates to a plate system for securing to a vertebrae or other osseous material that includes a retention cap and a locking feature integrated with a plate having screw holes adapted to receive bone screws. The retention cap comprises a head including tangs and a shank extending from the head, where the shank includes protrusions distal to the head and relief cut-outs extending towards the head from an end of the shank distal to the head. The relief cut-outs are clocked relative to the protrusions to provide rotational alignment control of the retention cap relative to the plate.

The plate system further includes an assembly guide proximal to a top surface of the plate adapted to guide the shank and features thereof into the locking feature. Locking detents distal to the top surface are adapted to receive the protrusions and interfere with rotational movement of the retention cap. A retainer positioned axially between the assembly guide and the locking detents prevents axial movement of the retention cap, and the retainer includes an annular extending rib adapted to axially interfere with the protrusions to prevent axial movement of the retention cap.

The retention cap exhibits alignment-dependent behavior through rotational alignment relative to the plate, where in a first rotational alignment the tangs are positioned between screw holes so as to not axially overlap with the screw holes, and in a second rotational alignment the tangs are positioned at least partially over the screw holes. The assembly guide guides the shank into the locking feature via an external thread on the shank and an internal thread of the assembly guide, and the retainer includes a blind recess bore adapted to receive the external thread therein to prevent backout of the retention cap.

Claims Coverage

The document includes two independent claims. Across these independent claims, the coverage centers on a retention cap with clocked relief cut-outs and tangs, a plate locking feature with an assembly guide and locking detents that interfere with rotational movement, axial anti-movement using a retainer with an annular extending rib and blind recess bore, and rotational alignment-dependent placement of tangs relative to screw holes.

Across the independent claims, the main inventive coverage combines a retention cap whose shank relief cut-outs are clocked relative to protrusions with tangs whose position changes based on rotational alignment relative to screw holes, together with a plate locking feature that uses an assembly guide and rotation-interfering locking detents. Axial retention is provided by a retainer positioned axially between the assembly guide and the locking detents, including an annular extending rib adapted to axially interfere with protrusions. Additional refinement specifies threaded guidance and a blind recess bore to prevent backout.

Stated Advantages

Documented Applications