Polyaxial bone screw with spherical capture, compression insert and alignment and retention structures
OwnerRoger P. Jacksoninventor
Life of this patent
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Abstract
A polyaxial bone screw assembly includes a receiver, a shank, an articulation structure for retaining the shank in the receiver and a compression insert for engagement with a longitudinal connecting member such as a rod. The articulation structure includes substantially spherical convex and concave surfaces that slidably engage both shank and receiver surfaces to provide compound articulation between the receiver and the shank. The receiver includes inwardly directed spring tabs engaging the insert and prohibiting rotation of the insert within the receiver.
Claims20
A polyaxial bone screw assembly for receiving a spinal rod, the polyaxial screw assembly comprising:
- a shank for anchoring the polyaxial bone screw assembly in bone;
- a receiver comprising a first channel for receiving the spinal rod;
- a retainer including a slit extending through a top surface and a bottom surface, wherein the slit is disposed at an oblique angle relative to the top surface and the bottom surface;
- a compression insert disposable in the receiver, the compression insert having a rod seat for contacting the spinal rod and a mating surface that pivotally mates with the shank;
- and
- a closure structure insertable into the receiver, the closure structure configured for urging the spinal rod into engagement with the compression insert thereby urging the compression insert into engagement with the shank,
- wherein the polyaxial screw assembly has:
- an unlocked position in which the receiver pivots with respect to the shank and the retainer pivots with respect to both the receiver and the shank, and
- a locked position in which the receiver, retainer, and shank are locked in motion relative to each other.
A polyaxial bone screw assembly for receiving a spinal rod, the polyaxial bone screw assembly comprising:
- a shank for anchoring the polyaxial bone screw assembly in bone;
- a receiver comprising a first channel for receiving the spinal rod;
- a retainer, wherein the retainer defines an outer groove configured to provide clearance when the retainer is disposed within the receiver and when the retainer is expanded about a spherical surface the shank;
- a compression insert disposable in the receiver, the compression insert having a rod seat for contacting the spinal rod and a mating surface that pivotally mates with the shank;
- and
- a closure structure insertable into the receiver, the closure structure configured for urging the spinal rod into engagement with the compression insert thereby urging the compression insert into engagement with the shank,
- wherein the polyaxial screw assembly has:
- an unlocked position in which the receiver pivots with respect to the shank and the retainer pivots with respect to both the receiver and the shank, and
- a locked position in which the receiver, retainer, and shank are locked in motion relative to each other.
A The polyaxial bone screw assembly for receiving a spinal rod, the polyaxial bone screw assembly comprising:
- a shank for anchoring the polyaxial bone screw assembly in bone;
- a receiver comprising a first channel for receiving the spinal rod;
- a retainer, wherein the retainer defines:
- a planar annular top;
- a bottom surface;
- an inner neck;
- a curved surface between the planar annular top and the inner neck;
- and an inner chamfer running between the inner neck and the bottom surface;
- a compression insert disposable in the receiver, the compression insert having a rod seat for contacting the spinal rod and a mating surface that pivotally mates with the shank;
- and
- a closure structure insertable into the receiver, the closure structure configured for urging the spinal rod into engagement with the compression insert thereby urging the compression insert into engagement with the shank,
- wherein the polyaxial screw assembly has:
- an unlocked position in which the receiver pivots with respect to the shank and the retainer pivots with respect to both the receiver and the shank, and
- a locked position in which the receiver, retainer, and shank are locked in motion relative to each other.
Dependencies are inferred from the claim text.