Coupling device for coupling a rod to a bone anchor and system including such a coupling device and at least two bone anchors

Patent metadata

Field	Value
Publication number	US-12383312-B2
Application number	US-202418981083-A
Country	US
Kind code	B2
Filing date	Dec 13, 2024
Priority date	Dec 15, 2023
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

A system for coupling a rod to bone includes different first and second bone anchors and a coupling device including a receiving part with a rod receiving portion for receiving a rod and a head receiving portion for interchangeably accommodating a head of either the first or second bone anchors, and a locking member positionable at least partially around the head receiving portion and movable between a first position where the held head is movable relative to the receiving part and a second position where the held head is locked relative to the receiving part. The coupling device includes a restraining surface configured to restrict pivoting of the first bone anchor relative to the receiving part, while the coupling device is configured to restrict pivoting of the second bone anchor relative to the receiving part differently than the restricted pivoting of the first bone anchor relative to the receiving part.

First claim

What is claimed is:

1. A system for coupling a rod to bone, the system comprising:
a first bone anchor comprising a first shank for anchoring to bone and a first head;
a second bone anchor different from the first bone anchor and comprising a second shank for anchoring to bone and a second head; and
a coupling device comprising:
a receiving part having a first end, an opposite second end, and a central axis extending between the first end and the second end, the receiving part comprising a rod receiving portion at the first end for receiving a rod, and a head receiving portion at the second end that defines an accommodation space for interchangeably accommodating the first head of the first bone anchor or the second head of the second bone anchor; and
a locking member positionable at least partially around the head receiving portion and movable between at least a first position where a head that is held in the accommodation space is movable relative to the receiving part, and a second position where the head that is held in the accommodation space is locked relative to the receiving part;

wherein the coupling device comprises a restraining surface configured to cooperate with the first bone anchor to restrict pivoting of the first bone anchor relative to the receiving part, and wherein the coupling device is configured to cooperate with the second bone anchor to restrict pivoting of the second bone anchor relative to the receiving part differently than the restricted pivoting of the first bone anchor relative to the receiving part.

2. The system of claim 1 , wherein when either the first bone anchor or the second bone anchor is connected to the receiving part, the connected bone anchor is configured to assume a plurality of angular positions relative to the receiving part.

3. The system of claim 1 , wherein when the first bone anchor is connected to the receiving part, the restraining surface restricts pivoting of the first bone anchor relative to the receiving part within a single plane that includes the central axis.

4. The system of claim 3 , wherein when the second bone anchor is connected to the receiving part, the second bone anchor is pivotable in multiple different planes relative to the receiving part.

5. The system of claim 1 , wherein when the first bone anchor is connected to the receiving part, the restraining surface forms a monoaxial connection where the first bone anchor is prevented from pivoting away from the central axis of the receiving part in every radial direction.

6. The system of claim 1 , wherein the restraining surface defines at least one recess in the head receiving portion that is configured to cooperate with a corresponding restraining structure of the first bone anchor to restrict the pivoting of the first bone anchor.

7. The system of claim 6 , wherein the at least one recess extends from an inner surface of the head receiving portion that defines the accommodation space towards an outer surface of the head receiving portion.

8. The system of claim 6 , wherein the at least one recess comprises two recesses that are offset from one another by 180°.

9. The system of claim 6 , wherein the accommodation space has a spherical segment-shaped portion including a greatest inner width of the sphere measured in a direction perpendicular to the central axis, and wherein the at least one recess extends axially through a portion of the accommodation space with the greatest inner width of the sphere.

10. The system of claim 1 , wherein the head receiving portion further comprises a cutout portion at the second end of the receiving part configured to facilitate angulation of a connected bone anchor at an enlarged pivot angle relative to the receiving part in at least one direction with respect to the central axis.

11. The system of claim 10 , wherein the cutout portion is substantially aligned with the restraining surface in a circumferential direction around the central axis.

12. The system of claim 1 , wherein the head receiving portion defines a plurality of slits that extend from the second end of the receiving part towards the first end of the receiving part, the slits forming a plurality of wall sections that render the head receiving portion compressible and/or expandable.

13. The system of claim 12 , wherein at least one of the plurality of wall sections is configured to be separated from the rest of the receiving part to form a cutout portion of the receiving part configured to facilitate angulation of a connected bone anchor at an enlarged pivot angle relative to the receiving part in at least one direction with respect to the central axis.

14. The system of claim 1 , wherein a wall of the head receiving portion comprises at least one cavity configured to reduce a thickness of the wall in a radial direction between the accommodation space and an outer surface of the head receiving portion.

15. The system of claim 1 , wherein an outer surface of the head receiving portion and an inner surface of the locking member are configured to cooperate in a manner such that adjusting the locking member from the first position to the second position increases a compression force of the locking member on the head receiving portion to clamp an inserted head in the receiving part.

16. The system of claim 1 , further comprising a pressure member positionable in the receiving part to exert pressure on an inserted head to clamp the head at a particular angular position relative to the receiving part.

17. The system of claim 1 , wherein the head of the first bone anchor has a substantially spherically-shaped outer surface portion and further comprises a restraining surface formed by a projection at the outer surface portion that is configured to cooperate with the restraining surface of the coupling device.

18. A method for coupling a rod to a bone using a system comprising a first bone anchor comprising a first shank for anchoring to bone and a first head, a second bone anchor different from the first bone anchor and comprising a second shank for anchoring to bone and a second head, and a coupling device comprising a receiving part having a first end, an opposite second end, and a central axis extending between the first end and the second end, the receiving part comprising a rod receiving portion at the first end for receiving a rod, and a head receiving portion at the second end that defines an accommodation space for interchangeably accommodating the first head of the first bone anchor or the second head of the second bone anchor, and a locking member positionable at least partially around the head receiving portion, the method comprising:
selecting the first bone anchor or the second bone anchor and assembling the selected bone anchor to the coupling device when the locking member is at a first position;
moving the receiving part relative to the head of the selected bone anchor that is held in the accommodation space to a desired position when the locking member is at the first position, wherein the coupling device comprises a restraining surface configured to cooperate with the first bone anchor to restrict pivoting of the first bone anchor relative to the receiving part, and wherein the coupling device is configured to cooperate with the second bone anchor to restrict pivoting of the second bone anchor relative to the receiving part differently than the restricted pivoting of the first bone anchor relative to the receiving part; and
adjusting the locking member from the first position to a second position, such that the head of the selected bone anchor

Assignees

• Biedermann Technologies Gmbh

Inventors

• Biedermann Lutz
• Biedermann Timo
• Fischer Bernd
• Dannecker Berthold

Classifications

• A61B17/7002

  Longitudinal elements, e.g. rods · CPC title

• A61B17/7074

  Tools specially adapted for spinal fixation operations other than for bone removal or filler handling (A61B17/7062, A61B17/808, A61B17/8858 take precedence; for spinal image producing devices A61B90/36, A61B34/20; markers A61B90/39) · CPC title

• A61B17/7064 Primary

  Devices acting on, attached to, or simulating the effect of, vertebral facets; Tools therefor · CPC title

• A61B2017/00477

  Coupling (A61B2017/0046 takes precedence) · CPC title

• A61B17/7038 Primary

  to a different extent in different directions, e.g. within one plane only · CPC title