FLEXIBLE TAP
Examples of the present invention relate to a flexible tap and method for forming a thread in bone. In one example, the tap threads a curved hole in a bone for receiving a flexible threaded component.
1 . A bone tap comprising:
a first member including a tap head having a tooth operable to form a thread in bone, an elongated flexible shaft having a first end connected to the tap head and a second end opposite the first end, and a drive thread having a thread pitch; and
a second member threadably engaged with the first member, the second member having a bone engagement portion.
2 . The bone tap of claim 1 wherein the first member includes a driving shaft having a first end connected to the second end of the flexible shaft, the driving shaft including the thread.
3 . The bone tap of claim 2 wherein the flexible shaft is operable to bend to allow the tap head to follow a curved path in the bone.
4 . The bone tap of claim 2 wherein the thread of the driving shaft is a multi-lead thread.
5 . The bone tap of claim 2 wherein the driving shaft is rigid.
6 . The bone tap of claim 2 wherein the driving shaft includes a second end opposite the first end of the driving shaft, the second end releasably engageable with a driver.
7 . The bone tap of claim 2 wherein the bone engagement portion includes a bone engagement feature selected from the group consisting of barbs, pins, screws and expandable members.
8 . The bone tap of claim 2 wherein the second member comprises a hollow shaft having an internal thread engaged with the driving shaft thread.
9 . The bone tap of claim 8 wherein the bone engagement portion comprises a self-tapping thread formed on a leading end of the hollow shaft.
10 . The bone tap of claim 9 wherein the hollow shaft comprises a knob operable to rotate the self-tapping thread into bone.
11 . The bone tap of claim 8 wherein the internal thread and the driving shaft thread have a common thread pitch, the driving shaft being operable to advance the tap head a distance corresponding to the thread pitch with each rotation of the driving shaft relative to the second member.
12 . The bone tap of claim 1 wherein the tap head has only a single tooth operable to form a spiral thread in the bone as the tap head is advanced relative to the second member.
13 . The bone tap of claim 1 wherein the tap head has two teeth operable to form a spiral thread in the bone as the tap head is advanced relative to the second member.
14 . A method of forming a thread in a bone, the method comprising:
engaging a tap with a bone to fix an anchor member of the tap relative to the bone, the anchor member including a drive thread having a thread pitch; and
rotating a driving shaft relative to the anchor member, the driving shaft being threadably engaged with the drive thread of the anchor member to advance the driving shaft a distance equal to the thread pitch with each full rotation of the driving shaft, the driving shaft driving a tap head to form a thread in the bone, the thread in the bone having a thread pitch corresponding to the drive thread pitch.
15 . The method of claim 14 wherein the tap head is connected to the driving shaft by a flexible shaft and further wherein rotating the driving shaft drives the tap head to follow a curved path in the bone.
16 . The method of claim 15 further comprising forming a curved hole in the bone and wherein rotating the driving shaft drives the tap head to follow the curved hole.
17 . The method of claim 15 further comprising inserting a wire into the bone to define a curved path and wherein rotating the driving shaft drives the tap head to follow the wire along the curved path.
18 . The method of claim 15 wherein the anchor member comprises a hollow shaft having an internal drive thread and the driving shaft has an external thread engageable with the internal drive thread.
19 . The method of claim 18 wherein the anchor member includes a bone engagement feature selected from the group consisting of barbs, pins, screws and expandable members.
20 . The method of claim 18 wherein the anchor member further comprises an external anchor thread at a leading end and wherein engaging the tap with the bone comprises screwing the external anchor thread of the anchor member into the bone.