Bone anchoring device

1. A bone anchoring device for anchoring in a bone comprising:

a hollow shaft having a proximal end, a distal end configured to be inserted into a bone before the proximal end and an outer surface comprising a first portion at the proximal end and a second portion at the distal end, the second portion having a larger outer diameter than the first portion; and

a barb carrier comprising a shaft member, a head member, and at least two barb elements, wherein the barb carrier is configured to be secured inside the second portion with the head member forming an outside surface at the distal end of the hollow shaft, and each barb element is configured to project through the second portion;

wherein the proximal end of the hollow shaft has an opening into the hollow shaft to receive a tool to move the barb carrier;

wherein a length of the hollow shaft from the opening to the second portion is greater than a length of the second portion;

wherein the hollow shaft and the barb carrier can be moved relative to each other in such a manner that in a first configuration the barb elements of the barb carrier project beyond an outer surface of the hollow shaft by a first distance;

wherein the hollow shaft and the barb carrier can be moved relative to each other in such a manner that in a second configuration the barb elements of the barb carrier project beyond the outer surface of the hollow shaft by a greater amount than in the first configuration; and

wherein the head member is configured to move in an axial direction of the hollow shaft when the barb carrier moves from the first configuration to the second configuration.

2. The bone anchoring device according to claim 1 , wherein the bone anchoring device comprises a screw having a head, and the barb carrier comprises an inner thread, and wherein the movement from the first to the second configuration is achievable by rotating the screw.

3. The bone anchoring device according to claim 1 , wherein the hollow shaft has a plurality of openings and wherein in the second configuration the barb elements are guided by the openings.

4. The bone anchoring device according to claim 3 , wherein in the first configuration the barb elements are guided by the openings.

5. The bone anchoring device according to claim 1 , wherein the head member includes a cone-shaped portion forming a tip of the bone anchoring device.

6. The bone anchoring device according to claim 1 , wherein the barb carrier is a sleeve.

7. The bone anchoring device according to claim 1 , wherein the barb elements are pins.

8. The bone anchoring device according to claim 1 , wherein the barb elements and the barb carrier are integrally connected.

9. The bone anchoring device according to claim 1 , wherein the barb elements are made of shape memory material.

10. The bone anchoring device according to claim 1 , wherein the barb elements are arranged in a pinfeather- or arrow-like configuration, wherein free ends of the barb elements are directed toward the proximal end of the hollow shaft.

11. The bone anchoring device according to claim 2 , wherein the screw is held axially fixed such as the screw only can perform a rotational movement.

12. The bone anchoring device according to claim 2 , wherein the head of the screw is axially fixed between a first abutment and a second abutment.

13. The bone anchoring device according to claim 3 , wherein the barb elements and the openings cooperate in such a manner, that the barb elements penetrate surrounding bone structure in the second configuration.

14. The bone anchoring device according to claim 2 , wherein the head of the screw is axially fixed by at least one abutment.

15. The bone anchoring device according to claim 1 , wherein a moving direction of the barb carrier from the first to the second configuration is against the insertion direction of the bone anchoring device.

16. The bone anchoring device according to claim 1 , wherein the hollow shaft and the barb carrier can be moved relative to each other in such a manner that in a third configuration the barb elements of the barb carrier do not project beyond an outer surface of the hollow shaft.

17. A bone anchoring device for anchoring in a bone comprising:

a hollow shaft having a proximal end, a distal end configured to be inserted into a bone before the proximal end and an outer surface comprising a threadless first portion;

a barb carrier comprising a shaft member and a head member, wherein the head member has a larger outer diameter than the shaft member, and the head member is configured to be located at the distal end of the hollow shaft;

at least two barb elements spaced apart along an axial direction, each barb element having a first end attached to the barb carrier and a second end opposite the first end;

a screw configured to threadably engage with and move the barb carrier; and

an abutment member configured to be inserted into the hollow shaft and fixed to the hollow shaft to maintain the abutment member at a fixed axial position within the hollow shaft, and to abut against the screw;

wherein the hollow shaft and the barb carrier can be moved relative to each other in such a manner that in a first configuration the barb elements of the barb carrier project beyond an outer surface of the hollow shaft by a first distance; and

wherein the hollow shaft and the barb carrier can be moved relative to each other in such a manner that in a second configuration the barb elements of the barb carrier project beyond the outer surface of the hollow shaft by a greater amount than in the first configuration.

18. The bone anchoring device according to claim 17 , wherein the hollow shaft and the barb carrier can be moved relative to each other in such a manner that in a third configuration the barb elements of the barb carrier do not project beyond an outer surface of the hollow shaft.

19. A method of attaching a bone anchoring device to a bone or a vertebra, the bone anchoring device comprising a hollow shaft having a proximal end, a distal end configured to be inserted into a bone before the proximal end and an outer surface comprising a first portion at the proximal end and a threadless second portion at the distal end, the second portion having a larger outer diameter than the first portion; and

a barb carrier comprising a shaft member, a head member, and at least two barb elements, wherein the barb carrier is configured to be secured inside the second portion with the head member forming an outside surface at the distal end of the hollow shaft, and each barb element configured to project through the second portion;

wherein the proximal end of the hollow shaft has an opening into the hollow shaft to receive a tool to move the barb carrier;

wherein a length of the hollow shaft from the opening to the second portion is greater than a length of the second portion;

wherein the hollow shaft and the barb carrier can be moved relative to each other in such a manner that in a first configuration the barb elements of the barb carrier project beyond an outer surface of the hollow shaft by a first distance;

wherein the hollow shaft and the barb carrier can be moved relative to each other in such a manner that in a second configuration the barb elements of the barb carrier project beyond the outer surface of the hollow shaft by a greater amount than in the first configuration; and

wherein the head member is configured to move in an axial direction of the hollow shaft when the barb carrier moves from the first configuration to the second configuration, the method comprising:

inserting the bone anchoring device into a bone, beginning with the distal end; and

moving the barb carrier relative to the hollow shaft to move the barb carrier to the second configuration.

20. A bone anchoring device for anchoring in a bone comprising:

a hollow shaft having a proximal end, a distal end configured to be inserted into a bone before the proximal end and an outer surface comprising a first portion at the proximal end and a second portion at the distal end, the second portion having a larger outer diameter than the first portion;

a barb carrier comprising a shaft member and at least two barb elements, wherein the barb carrier is configured to be secured inside the second portion, a length of the shaft member is greater than a length of at least one of the barb elements, and each barb element is configured to project through the second portion; and

a screw configured to threadably engage with and move the barb carrier;

wherein the proximal end of the hollow shaft has an opening into the hollow shaft to receive a tool to move the barb carrier;

wherein a length of the hollow shaft from the opening to the second portion is greater than a length of the second portion;

wherein the hollow shaft and the barb carrier can be moved relative to each other in such a manner that in a first configuration the barb elements of the barb carrier project beyond an outer surface of the hollow shaft by a first distance; and

wherein the hollow shaft and the barb carrier can be moved relative to each other in such a manner that in a second configuration the barb elements of the barb carrier project beyond the outer surface of the hollow shaft by a greater amount than in the first configuration.

21. A bone anchoring device for anchoring in a bone comprising:

a hollow shaft having a proximal end, a distal end configured to be inserted into a bone before the proximal end and an outer surface comprising a first portion at the proximal end and a second portion at the distal end;

a barb carrier;

at least two barb elements spaced apart along an axial direction, each barb element having a first end attached to the barb carrier and a second end opposite the first end;

a screw configured to threadably engage with and move the barb carrier; and

an abutment member configured to be secured inside the first portion of the hollow shaft and fixed to the hollow shaft to maintain the abutment member at a fixed axial position within the hollow shaft, and to abut against the screw;

wherein the hollow shaft and the barb carrier can be moved relative to each other in such a manner that in a first configuration the barb elements of the barb carrier project beyond an outer surface of the hollow shaft by a first distance; and

wherein the hollow shaft and the barb carrier can be moved relative to each other in such a manner that in a second configuration the barb elements of the barb carrier project beyond the outer surface of the hollow shaft by a greater amount than in the first configuration.