Bone anchoring device

Abstract

A bone anchoring device includes a shaft for anchoring in a bone and a head, the shaft including a first section having a plurality of barb elements, the barb elements being elastically deformable relative to the body of the shaft, and a second section including a bone thread for engagement with the bone. The first section is located near the tip of the shaft and allows insertion by pushing whereas the second section provides enhanced resistance against pull-out.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the invention will become apparent and will be best understood by reference to the following detailed description of embodiments taken in conjunction with the accompanying drawings.

FIG. 1 shows a side view of a bone anchoring device according to a first embodiment in a first condition.

FIG. 2 shows a cross-sectional view of the bone anchoring device of FIG. 1 along a line A-A.

FIG. 3 shows the bone anchoring device of FIG. 1 in a second condition with expanded barb elements.

FIG. 4 shows a partially exploded view of the bone anchoring device of FIG. 3.

FIG. 5 shows the anchoring device according to the first embodiment in the process of being anchored in a vertebra.

FIG. 6 shows a partially sectional side view of a bone anchoring device according to a second embodiment in the second condition corresponding to the first embodiment shown in FIG. 3.

FIG. 7 is a partially exploded view of the bone anchoring device of FIG. 6.

FIG. 8 shows a bone anchoring device according to a third embodiment.

FIG. 9 shows a partially exploded view of a bone anchoring device according to a fourth embodiment.

FIG. 10 shows a partially exploded view of a bone anchoring device according to a fifth embodiment.

FIG. 11 is a schematic representation of the bone anchoring device of FIG. 9 as applied to a fracture of the tibia.

FIG. 12 is a schematic representation of the bone anchoring device of FIG. 10 as applied to a fracture of a tibia.

Claims

1. A bone anchoring device comprising: a head portion; anda shaft for anchoring in a bone, the shaft comprising:a first section comprising a plurality of barb elements, the barb elements being elastically deformable relative to the shaft, anda second section comprising a bone thread for engagement with the bone;wherein the shaft has a free end opposite to the head portion and the first section is provided between the second section and the free end.

2. The bone anchoring device of claim 1, wherein the second section is arranged adjacent to the head portion.

3. The bone anchoring device of claim 1, wherein the barb elements are arranged on at least one helical line around the shaft.

4. The bone anchoring device of claim 3, wherein a pitch of the helical line is the same as a pitch of the bone thread of the second section.

5. The bone anchoring device of claim 3, wherein the barb elements form at least two turns of the helical line.

6. The bone anchoring device of claim 1, wherein the length of the first section is at least approximately twice the length of the second section.

7. The bone anchoring device of claim 1, wherein the first section is detachably mounted to the second section.

8. The bone anchoring device of claims 1, wherein the first section is provided on a tubular body.

9. The bone anchoring device of claim 8, wherein the barb elements are cut out of a wall of the tubular body.

10. The bone anchoring device of claim 1, wherein the head portion comprises a recess for receiving a rod.

11. The bone anchoring device of claim 1, wherein the head and the shaft are fixedly connected.

12. The bone anchoring device of claim 1, wherein the head and the shaft are connected such as to allow pivoting of the shaft relative to the head.

13. The bone anchoring device of claim 12, comprising means for locking the pivoting movement of the shaft relative to the head.

14. The bone anchoring device of claim 1, wherein the barb elements are made of a shape-memory material.

15. The bone anchoring device of claim 14, wherein the barb elements comprise nitinol.

16. The bone anchoring device of claim 1, wherein free ends of the barb elements face towards the head portion.

17. The bone anchoring device of claim 1, wherein the barb elements are arranged to prevent extraction without rotation of the bone anchoring device.

18. The bone anchoring device of claim 1, wherein the head and the shaft are separate parts.

19. A bone anchoring comprising: a head portion; anda shaft for anchoring in a bone, the shaft comprising:a first section comprising a plurality of barb elements arranged on at least one helical line around the shaft, the barb elements being elastically deformable relative to the shaft; anda second section comprising a bone thread for engagement with the bone.

20. The bone anchoring device of claim 19, wherein a pitch of the helical line is the same as a pitch of the bone thread of the second section.

21. A method of using a bone anchoring element, the method comprising: inserting a first section of a shaft into a core hole prepared in a bone up to a second section of the shaft, the first section comprising a plurality of barb elements arranged on at least one helical line around the shaft and the second section comprising a bone thread for engagement with the bone; andturning the shaft after insertion of the first section of the shaft into the core hole in any one of a first direction and a second direction being opposite the first direction, the turning of the shaft in the first direction causing the shaft to be moved in an insertion direction deeper in the core hole, and the turning of the shaft in the second direction causing the shaft to be moved in the core hole opposite to the insertion direction;wherein the barb elements are moveable between a first position adjacent to a surface of the shaft and a second position farther from the surface of the shaft than the first position to prevent the shaft from being pulled out of the core hole when the first section is inserted into the core hole.

22. The method of claim 21, wherein the barb elements are constructed from a shape memory alloy such that the barb elements are moved into the second position upon being exposed to heat from the bone.