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US 6,663,635 B2Granted
Bone screw with two-part screw head
AssigneeSynthes USA, LLC
InventorsRobert Frigg, Robert Ferus
Life of this patent
Estimating the term…
Abstract
The invention is related to a fastener and a bone fixation assembly for the internal fixation of vertebral bodies. The bone fastener includes a shank having a longitudinal axis, a head positioned adjacent the top end of the shank and having at least two portions separable in the axial direction. The head includes a bottom portion connected to the shank and a top portion connectable to the bottom portion. The bottom portion defines a socket situated coaxially to the longitudinal axis to accept a driver to rotate the fastener, and the top portion has an exterior with a convex design.
Claims37
A bone fixation device comprising:
- a bone fastener comprising:
- a shank having a longitudinal axis extending from a bottom end to a top end;
- a head positioned adjacent the top end of the shank and having at least two portions separable in the axial direction, the head comprising a bottom portion connected to the shank and a top portion attachable to the bottom portion;
- wherein the bottom portion defines a socket situated coaxially to the longitudinal axis to accept a driver to rotate the fastener;
- and
- wherein the top portion has an exterior with a convex design and the top portion at least partially covers the socket when the top portion is connected to the bottom portion;
- a bone plate comprising a plate bore configured and dimensioned to receive the bone fastener.
4 more elements
A bone fastener comprising:
- a shank having a longitudinal axis extending from a bottom end to a top end;
- a head positioned adjacent the top end of the shank and having at least two portions separable in the axial direction, the head comprising a bottom portion connected to the shank and a top portion attachable to the bottom portion;
- wherein the bottom portion defines a socket situated coaxially to the longitudinal axis to accept a driver to rotate the fastener;
- wherein the top portion has an exterior with a convex design and the top portion at least partially coven the socket when the top portion is connected to the bottom portion;
- and
- wherein the top portion is attached to the bottom portion by means of a bayonet connection.
3 more elements
A bone fastener comprising:
- a shank having a longitudinal axis extending from a bottom end to a top end;
- a head positioned adjacent the top end of the shank and having at least two portions separable in the axial direction, the head comprising a bottom portion connected to the shank and a top portion attachable to the bottom portion;
- wherein the bottom portion defines a socket situated coaxially to the longitudinal axis to accept a driver to rotate the fastener;
- wherein the top portion has an exterior with a convex design and the top portion at least partially covers the socket when the top portion is connected to the bottom portion;
- wherein the bottom portion has an exterior surface adjacent the shank that is convex shaped;
- and
- wherein the bottom portion exterior surface includes a segment of a sphere adjacent the shank.
4 more elements
A bone fixation device comprising:
- (1) at least one bone fastener comprising:
- a shank having a longitudinal axis extending from a bottom end to a top end;
- a head positioned adjacent the top end of the shank and having at least two portions separable in the axial direction, the head comprising a bottom portion connected to the shank and a top portion attachable to the bottom portion;
- wherein the bottom portion defines a socket situated coaxially to the longitudinal axis to accept a driver to rotate the fastener;
- and
- wherein the top portion has an exterior with a convex design and the top portion at least partially covers the socket when the top portion is connected to the bottom portion;
- and
- (2) at least one fixation body having at least one bore with a central axis for receiving the bone fastener and defining an bore inner surface, wherein the bottom portion is dimensioned to contact the inner surface at different angles between the longitudinal axis of the shank and the central axis.
5 more elements
A bone fastener comprising:
- a threaded shank comprising an integrally formed, protruding bearing surface disposed proximate an end of the shank, a bore extending proximate a longitudinal axis of the shank, and a socket configured and dimensioned to receive a tool;
- a head portion demountably attachable to the shank and comprising a partially spherical top part and a peg configured and dimensioned to be received in the bore;
- wherein the bearing surface is partially spherical.
A bone fixation device comprising:
- (1) a first bone fastener comprising:
- a threaded shank comprising an integrally formed, protruding bearing surface disposed proximate an end thereof, a bore extending proximate a longitudinal axis of the shank, and a socket configured and dimensioned to receive a tool;
- and
- a head portion demountably attachable to the shank and comprising a partially spherical top part and a peg configured and dimensioned to be received in the bore;
- (2) a bone plate comprising a plate bore configured and dimensioned to receive the first bone fastener;
- wherein the shank is positionable in a range of angles within the plate bore.
3 more elements
Dependencies are inferred from the claim text.