BONE ANCHORING DEVICE

• US 20190290333A1
• Filed: 06/13/2019
• Published: 09/26/2019
• Est. Priority Date: 01/30/2012
• Status: Active Grant

• Current Assignee: Biedermann Technologies GmbH & Co. KG
• Original Assignee: Biedermann Technologies GmbH & Co. KG
• Inventors: Matthis, Wilfried, Meer, Martin, Biedermann, Lutz
• Granted Patent: US 10,448,976 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 17/7002 Longitudinal elements, e.g. rods
• CPC Class Codes: A61B 17/7034 characterised by a lateral opening
• CPC Class Codes: A61B 17/7035 Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other
• CPC Class Codes: A61B 17/7037 wherein pivoting is blocked when the rod is clamped
• CPC Class Codes: A61B 17/8605 Heads, i.e. proximal ends projecting from bone
• CPC Class Codes: A61B 2017/00526 Methods of manufacturing
• CPC Class Codes: F04C 2270/041 Controlled or regulated

Abstract

A polyaxial bone anchoring device includes a bone anchoring element having a head and a shaft, a receiving part having a head receiving portion, a rod receiving portion, and a bore having a bore axis, and a pressure member movable in the bore and having a first surface for engaging the head, wherein the pressure member is movable to a first position where friction between the first surface and the head generates a preload on the head to maintain the shaft at a temporary angular position relative to the receiving part, and wherein the pressure member is configured to engage the receiving part to generate a holding force for holding the pressure member at the first position without a positive lock, and wherein the pressure member is movable in and out of the first position by applying an axial force on the pressure member greater than the holding force.

Claims

1. A polyaxial bone anchoring device comprising:

a bone anchoring element having a head and a shaft for anchoring to a bone;

a receiving part for coupling the bone anchoring element to a rod, the receiving part having a first end and a second end, a head receiving portion at the second end with an accommodation space for accommodating the head, and a rod receiving portion at the first end defining a bore in communication with the accommodation space, the bore having a bore axis; and

a one-piece pressure member movable in the bore and comprising a first surface for engaging the head, a second surface for engaging a rod, and an outer surface;

wherein when the bone anchoring element and the pressure member are in the receiving part, the pressure member is configured to assume and be held at a first position where friction between the first surface and the head generates a preload on the head to maintain the shaft at a temporary angular position relative to the receiving part, and to a second position different from the first position where the head is locked relative to the receiving part; and

wherein the receiving part comprises a separate insert that is positionable in a recess formed in a side wall of the receiving part, such that when the pressure member is at the first position, a portion of the separate insert of the receiving part that is directed towards the bore axis exerts a holding force on the outer surface of the pressure member to restrict movement of the pressure member towards the first end of the receiving part, and wherein the pressure member is movable out of the first position towards the first end of the receiving part by applying a sufficient axial force on the pressure member while a position of the separate insert relative to the receiving part remains substantially constant.

2. The polyaxial bone anchoring device of claim 1, wherein when the pressure member is held at the first position by the separate insert of the receiving part, at least part of the holding force exerted by the separate insert of the receiving part on the outer surface of the pressure member is directed radially relative to the bore axis to generate friction between the pressure member and the receiving part.

3. The polyaxial bone anchoring device of claim 2, wherein the radially directed holding force exerted by the separate insert of the receiving part on the outer surface of the pressure member urges the pressure member into direct contact with another portion of the receiving part.

4. The polyaxial bone anchoring device of claim 3, wherein the recess extends entirely through the side wall of the receiving part in a radial direction.

5. The polyaxial bone anchoring device of claim 4, wherein the second surface of the pressure member forms two legs, and wherein the pressure member can assume a third position that is located above the first position towards the first end of the receiving part, and wherein the legs of the pressure member each has a same cross-sectional profile in the first and third positions.

6. The polyaxial bone anchoring device of claim 3, wherein the second surface of the pressure member forms two legs, and wherein the pressure member can assume a third position that is located above the first position towards the first end of the receiving part, and wherein the legs of the pressure member each has a same cross-sectional profile in the first and third positions.

7. The polyaxial bone anchoring device of claim 2, wherein the recess extends entirely through the side wall of the receiving part in a radial direction.

8. The polyaxial bone anchoring device of claim 7, wherein the second surface of the pressure member forms two legs, and wherein the pressure member can assume a third position that is located above the first position towards the first end of the receiving part, and wherein the legs of the pressure member each has a same cross-sectional profile in the first and third positions.

9. The polyaxial bone anchoring device of claim 2, wherein the second surface of the pressure member forms two legs, and wherein the pressure member can assume a third position that is located above the first position towards the first end of the receiving part, and wherein the legs of the pressure member each has a same cross-sectional profile in the first and third positions.

10. The polyaxial bone anchoring device of claim 1, wherein the recess extends entirely through the side wall of the receiving part in a radial direction.

11. The polyaxial bone anchoring device of claim 10, wherein the second surface of the pressure member forms two legs, and wherein the pressure member can assume a third position that is located above the first position towards the first end of the receiving part, and wherein the legs of the pressure member each has a same cross-sectional profile in the first and third positions.

12. The polyaxial bone anchoring device of claim 1, wherein the second surface of the pressure member forms two legs, and wherein the pressure member can assume a third position that is located above the first position towards the first end of the receiving part, and wherein the legs of the pressure member each has a same cross-sectional profile in the first and third positions.

13. The polyaxial bone anchoring device of claim 1, wherein at least a portion of the outer surface of the pressure member is roughened, fluted, grooved or ridged.

14. The polyaxial bone anchoring device of claim 1, wherein the pressure member has a first end and a second end, and wherein the first surface comprises a concave surface at the second end with a spherical-segment shape corresponding to a spherical-segment shaped surface portion of the head of the bone anchoring element.

15. The polyaxial bone anchoring device of claim 1, wherein the separate insert of the receiving part comprises a set screw, and wherein the pressure member is configured to be held in the first position when the set screw is in frictional contact with the outer surface of the pressure member.

16. The polyaxial bone anchoring device of claim 1, wherein the separate insert of the receiving part is monolithic.

17. The polyaxial bone anchoring device of claim 1, wherein the separate insert of the receiving part comprises a surface that extends helically around an axis of the separate insert.

18. The polyaxial bone anchoring device of claim 1, wherein the rod receiving portion further defines a channel that extends transversely to the bore axis for receiving the rod, and wherein at least part of the separate insert is positionable closer axially to the second end of the receiving part than a bottom of the channel is to the second end.

19. The polyaxial bone anchoring device of claim 1, wherein the separate insert of the receiving part is configured to exert the holding force on a portion of the outer surface that extends axially from an end of the pressure member with the first surface towards an opposite end of the pressure member with the second surface.

20. A polyaxial bone anchoring device comprising:

a bone anchoring element having a head and a shaft for anchoring to a bone;

a receiving part for coupling the bone anchoring element to a rod, the receiving part having a first end and a second end, a head receiving portion at the second end with an accommodation space for accommodating the head, and a rod receiving portion at the first end defining a bore in communication with the accommodation space, the bore having a bore axis; and

a one-piece pressure member movable in the bore and comprising a first surface for engaging the head, a second surface for engaging a rod, and an outer surface;

wherein when the bone anchoring element and the pressure member are in the receiving part, the pressure member is configured to assume and be held at a first position where friction between the first surface and the head generates a preload on the head to maintain the shaft at a temporary angular position relative to the receiving part, and to a second position different from the first position where the head is locked relative to the receiving part; and

wherein the receiving part comprises a separate insert that is positionable in a recess formed in a side wall of the receiving part, such that when the pressure member is at the first position, the separate insert of the receiving part exerts a holding force on the outer surface of the pressure member to restrict movement of the pressure member towards the first end of the receiving part, wherein at least part of the holding force acting on the outer surface of the pressure member is directed radially relative to the bore axis to generate friction between the pressure member and the receiving part, and wherein the pressure member is movable out of the first position towards the first end of the receiving part by applying a sufficient axial force on the pressure member while a position of the separate insert relative to the receiving part remains substantially constant.

21. The polyaxial bone anchoring device of claim 20, wherein the separate insert of the receiving part comprises a set screw, and wherein the pressure member is configured to be held in the first position when the set screw is in frictional contact with the outer surface of the pressure member.

22. The polyaxial bone anchoring device of claim 20, wherein the radially directed holding force exerted by the separate insert of the receiving part on the outer surface of the pressure member urges the pressure member into direct contact with another portion of the receiving part.

23. The polyaxial bone anchoring device of claim 22, wherein the recess extends entirely through the side wall of the receiving part in a radial direction.

24. The polyaxial bone anchoring device of claim 23, wherein the second surface of the pressure member forms two legs, and wherein the pressure member can assume a third position that is located above the first position towards the first end of the receiving part, and wherein the legs of the pressure member each has a same cross-sectional profile in the first and third positions.

25. The polyaxial bone anchoring device of claim 22, wherein the second surface of the pressure member forms two legs, and wherein the pressure member can assume a third position that is located above the first position towards the first end of the receiving part, and wherein the legs of the pressure member each has a same cross-sectional profile in the first and third positions.

26. The polyaxial bone anchoring device of claim 20, wherein the recess extends entirely through the side wall of the receiving part in a radial direction.

27. The polyaxial bone anchoring device of claim 26, wherein the second surface of the pressure member forms two legs, and wherein the pressure member can assume a third position that is located above the first position towards the first end of the receiving part, and wherein the legs of the pressure member each has a same cross-sectional profile in the first and third positions.

28. The polyaxial bone anchoring device of claim 20, wherein the second surface of the pressure member forms two legs, and wherein the pressure member can assume a third position that is located above the first position towards the first end of the receiving part, and wherein the legs of the pressure member each has a same cross-sectional profile in the first and third positions.