Blunt tip bone screw
AssigneeDePuy Synthes Products, Inc.
InventorJoel Patrick Bales
Life of this patent
Estimating the term…
Abstract
In one embodiment, a bone screw includes a shaft having a proximal shaft end and a distal shaft end spaced from the proximal shaft end in a distal direction along a central axis. The shaft is helically threaded between the proximal and distal shaft ends. A tip extends from the distal shaft end in the distal direction, and defines a plurality of lands with cutting flutes disposed between adjacent lands. Each land has a bore-cutting edge that extends from an inner cutting edge end to an outer cutting edge end. The inner cutting edge end is disposed at a center of the distal end of the tip, and the outer cutting edge end is spaced from the center of the distal end of the tip. The bore-cutting edges may blunt the feel of the tip so as to reduce the likelihood of soft-tissue damage.
Claims25
A method of fixing a bone screw to bone, the bone screw having a shaft and a tip that extends from the shaft in a distal direction along a central axis to a tip end, the method comprising:
- abutting the tip against a bone, wherein the tip defines a plurality of lands and a plurality of cutting flutes, each cutting flute disposed between a different pair of the lands, each of the lands defined by a leading side and a trailing side with respect to a first direction of rotation about the central axis, each leading side having a bore-cutting edge that defines a tip angle with respect to a plane that is perpendicular to the central axis, the tip angle in the range of 15 degrees to 30 degrees;
- rotating the bone screw in the first direction of rotation about the central axis, wherein 1) each bore-cutting edge cuts into the bone to form a bore in the bone, such that the bore has a curved inner surface, and 2) helical threading of the shaft purchases in the curved inner surface of the bore, the helical threading extending in the first direction of rotation as viewed along the distal direction;
- and
- during the rotating step, guiding chips cut from the bone away from the tip end in a proximal direction through the cutting flutes of the tip, wherein the proximal direction is opposite the distal direction.
A method of fixing a bone screw to bone, the bone screw having a shaft and a tip that extends from the shaft in a distal direction along a central axis to a tip end that is solid about the central axis and defines a single point, the method comprising:
- abutting the tip against a bone, wherein the tip defines a plurality of lands and a plurality of cutting flutes, each cutting flute disposed between a different pair of the lands, each of the lands having a bore-cutting edge configured to cut a bore into bone and an outer surface, and wherein the bore-cutting edge of each respective land of the plurality of lands extends radially out from an inner cutting-edge end that is disposed at the single point to an outer cutting-edge end that is spaced from the center of the tip end and that terminates on the outer surface of the respective land;
- rotating the bone screw in a first direction of rotation about the central axis, wherein 1) each bore-cutting edge cuts into the bone to form a bore in the bone, such that the bore has a curved inner surface, and 2) helical threading of the shaft purchases in the curved inner surface of the bore, the helical threading extending in the first direction of rotation as viewed along the distal direction;
- and
- during the rotating step, guiding chips cut from the bone away from the tip end in a proximal direction through the cutting flutes of the tip, wherein the proximal direction is opposite the distal direction.
Dependencies are inferred from the claim text.