Cannulated screw
AssigneeOrthopro LLC
InventorsJesse Jackson, Craig Schelling
Life of this patent
Estimating the term…
Abstract
A cannulated screw which maintains compression at the interface between two or more materials in a medical or other setting to effectively secure bone to bone while minimizing separation between the bones and the securement interface. The cannulated screw has a flattened tip, which enables the cannulated screw to more readily bore or self-tap into bone or other material. The flattened tip of the cannulated screw comprises a plurality of cutting teeth which facilitate boring of the flattened tip of the cannulated screw into the material into which the screw is being inserted. In one embodiment, three progressive cutting teeth are provided on the flattened tip of the cannulated screw.
Claims18
A self boring medical fastener for use in a medical setting for securing a first bone to a second bone, the self boring medical fastener adapted to cut on contact with the bone into which the self boring medical fastener is to be inserted to minimize separation at the bone securement interface as the self boring medical fastener passes from one bone to the second bone, the self boring medical fastener comprising:
- a cannula having a first portion, a second portion, an inner surface and an outer surface, wherein the first portion of the cannula includes one or more threads positioned in a spiral pattern along a portion of the length thereof, the one or more threads being sized and configured to secure the cannula to a bone, and wherein the second portion of the cannula is devoid of threads;
- an end of the cannula adjacent the second portion of the cannula comprising a head, the head extending radially outward from the cannula and being adapted to accommodate a rotational tool which provides the rotational force necessary to allow for self boring of the self boring medical fastener into material in which the self boring medical fastener is to be positioned;
- and
- an end of the cannula opposite the head and adjacent the one or more threads comprising a tip, the tip having at least three cutting teeth, each of the cutting teeth comprising:
- (i) a continuous leading cutting edge extending from the inner surface of the cannula at the tip, (ii) a ramp edge extending from the inner surface of the cannula at the tip, and (iii) a curved cutting surface extending from the leading cutting edge up to the ramp edge, wherein the continuous leading cutting edge and the curved cutting surface of each tooth are configured to cut material to form a path in a bone into which the one or more threads will follow as the self boring medical fastener is advanced into the bone;
- wherein a slope of the curved cutting surface from the leading cutting edge to the ramp edge of each cutting tooth gradually increases from a first tooth of the at least three cutting teeth to subsequent teeth of the at least three cutting teeth.
A self boring medical fastener for use in a medical setting and being adapted to cut on contact with the material into which the self boring medical fastener is to be inserted, the self boring medical fastener comprising,
- a cannula having an inner surface, an outer surface, and one or more threads positioned in a spiral pattern along a portion of the length of the cannula, the one or more threads being sized and configured to secure the cannula to a bone, and wherein another portion of the length of the cannula is devoid of threads;
- an end of the cannula comprising a head, the head being adapted to accommodate a rotational tool which provides the rotational force necessary to drive the self boring medical fastener into material in which the self boring medical fastener is to be positioned;
- and
- an end of the cannula opposite the head comprising a tip, the tip having a length that is less than one and half times the distance between adjacent threads along the length of the cannula, the tip comprising at least three progressive cutting teeth which cut on contact with the material into which the medical fastener is to be positioned, wherein a first cutting tooth has a continuous first leading cutting edge, a first ramp edge, and a curved cutting surface extending from the first leading edge to the ramp edge, wherein the first leading cutting edge extends from the inner surface of the cannula at the tip a first radial distance, and the first ramp edge extends from the inner surface of the cannula at the tip a second radial distance greater than the first radial distance, and each additional tooth of the at least three progressive cutting teeth provide a leading cutting edge extending from the inner surface of the cannula at the tip a radial distance greater than the first radial distance to remove an additional amount of material to provide self-boring of the medical fastener such that the cutting of the at least three cutting teeth minimizes the normal force against the material allowing for self-boring of the medical fastener while minimizing pressure against the material that could otherwise result in displacement of the material as a result of the contact with the self-boring medical fastener.
A self boring medical fastener for use in a medical setting and being adapted to cut on contact with the material into which the self boring medical fastener is to be inserted, the self boring medical fastener comprising,
- a cannula having an inner surface, outer surface, a neck portion devoid of threads, and one or more threads positioned in a spiral pattern along another portion of the length of the cannula, the one or more threads being sized and configured to secure the cannula to a bone;
- an end of the cannula comprising a head, the head extending radially outward from the outer surface of the cannula, the head being adapted to accommodate a rotational tool which provides the rotational force necessary to drive the self boring medical fastener into material in which the self boring medical fastener is to be positioned;
- and
- an end of the cannula opposite the head comprising a self-boring tip, the self-boring tip having a at least three teeth for progressive cutting, wherein a first cutting tooth has a continuous first leading cutting edge and a first ramp edge, and a first curved cutting surface extending from the first leading edge to the ramp edge, wherein the first leading cutting edge extends from the inner surface of the cannula radially and axially a first distance, and wherein each additional tooth of the at least three teeth for progressive cutting provides a leading cutting edge that extends from the inner surface of the cannula radially and axially a distance greater than the first distance, wherein the at least three teeth for progressive cutting provide self-boring of the medical fastener while minimizing pressure against the material that could otherwise result in displacement of the material as a result of the contact with the self-boring medical fastener.
Dependencies are inferred from the claim text.