Coupling device for coupling a rod to a bone anchor

Patent metadata

Field	Value
Publication number	US-12588933-B2
Application number	US-202318301136-A
Country	US
Kind code	B2
Filing date	Apr 14, 2023
Priority date	Oct 29, 2020
Publication date	Mar 31, 2026
Grant date	Mar 31, 2026

Abstract

A coupling device for coupling a rod to a bone anchor includes a receiving part configured to receive a head of the bone anchor, the receiving part having a first end and a second end, a central axis that extends between the first and second ends, and two legs at the first end that define a recess extending in a longitudinal direction transverse to the central axis for receiving the rod, and a monolithic pressure member positionable in the receiving part, the pressure member including a rod support surface and an engagement portion to adjust the pressure member to exert pressure on the head. The engagement portion is positioned farther radially from the central axis in the longitudinal direction than a first portion of the rod support surface, and extends closer axially to the first end of the receiving part than the entire first portion of the rod support surface.

First claim

What is claimed is:

1 . A coupling device for coupling a rod to a bone anchor, the coupling device comprising:
a receiving part configured to receive a head of the bone anchor, the receiving part having a first end and a second end, a central axis that extends between the first end and the second end, and two legs at the first end that define a recess for receiving the rod, wherein the recess extends in a longitudinal direction transverse to the central axis; and a monolithic pressure member positionable at least partially in the receiving part to exert pressure on an inserted head, the pressure member comprising a body that defines a rod support surface for supporting the rod and four arms, wherein each of the four arms is flexible and extends circumferentially around the central axis from a first end that is connected axially to another portion of the pressure member to a free second end that is configured to be positioned laterally outwardly from the body and at a different axial position than the entire rod support surface.

2 . The coupling device of claim 1 , wherein the four arms are engageable for adjusting the pressure member to exert pressure on the head.

3 . The coupling device of claim 2 , wherein the four arms are configured to engage another part of the coupling device.

4 . The coupling device of claim 2 , wherein the four arms are configured to engage an outside instrument.

5 . The coupling device of claim 1 , wherein when the pressure member is assembled with the receiving part, at least part of each of the four arms is positioned outside the legs of the receiving part in the longitudinal direction.

6 . The coupling device of claim 1 , further comprising a compressible surface forming a seat for the head that is configured to exert upward pressure on the head to lock the head in the receiving part.

7 . The coupling device of claim 6 , wherein the compressible surface is formed as part of the pressure member and defines a head receiving recess for receiving the head of the bone anchor.

8 . The coupling device of claim 1 , wherein when the pressure member is assembled with the receiving part, the free second end of each of the four arms is located farther away from the second end of the receiving part than the first end of each of the four arms is from the second end of the receiving part.

9 . The coupling device of claim 1 , wherein the body comprises a substantially cylindrical outer surface, and wherein at least part of each of the four arms is positioned laterally outwardly from the substantially cylindrical outer surface.

10 . The coupling device of claim 1 , wherein the receiving part defines an opening at the second end sized to facilitate insertion of the head of the bone anchor from the second end into the receiving part.

11 . The coupling device of claim 1 , wherein when viewed in a cross-section perpendicular to the central axis, a radially outwardly facing surface of each of the four arms extends circumferentially around the central axis in a curved manner.

12 . A bone anchoring device comprising:
a bone anchor comprising a head and a shank configured to be anchored in bone or in a vertebra; and a coupling device for coupling a rod to the bone anchor, the coupling device comprising:
a receiving part configured to receive the head of the bone anchor, the receiving part having a first end and a second end, a central axis that extends between the first end and the second end, two legs at the first end that define a recess for receiving the rod, wherein the recess extends in a longitudinal direction transverse to the central axis, and an opening at the second end sized to facilitate insertion of the head from the second end into the receiving part; and
a monolithic pressure member positionable at least partially in the receiving part to exert pressure on the head, the pressure member comprising a body that defines a rod support surface for supporting the rod and four arms, wherein each of the four arms extends circumferentially around the central axis from a first end that is connected axially to another portion of the pressure member to a free second end that is positioned laterally away from the body;
wherein when the head and the pressure member are assembled with the receiving part, the pressure member is movable to a pre-locking position where the head is restricted from removal from the receiving part and each of the four arms is configured to engage a corresponding abutting surface portion on the bone anchoring device to hold the pressure member at the pre-locking position.

13 . The bone anchoring device of claim 12 , wherein the free second end of each of the four arms is configured to be positioned at a different axial position than the entire rod support surface.

14 . The bone anchoring device of claim 12 , wherein when the pressure member is at the pre-locking position, the head is held by friction in the receiving part to temporarily hold an angular position of the bone anchor relative to the receiving part.

15 . The bone anchoring device of claim 12 , wherein the abutting surface portions are formed on the receiving part, such that when the pressure member is at the pre-locking position, each of the four arms is configured to cooperate with the corresponding abutting surface portion on the receiving part to limit movement of the pressure member away from the second end of the receiving part.

16 . The bone anchoring device of claim 12 , wherein each of the four arms is flexible.

17 . The bone anchoring device of claim 12 , further comprising a compressible surface forming a seat for the head that is configured to exert upward pressure on the head to lock the head in the receiving part.

18 . The bone anchoring device of claim 17 , wherein the compressible surface is formed as part of the pressure member and defines a head receiving recess for receiving the head of the bone anchor.

19 . The bone anchoring device of claim 12 , wherein when viewed in a cross-section perpendicular to the central axis, a radially outwardly facing surface of each of the four arms extends circumferentially around the central axis in a curved manner.

20 . A coupling device for coupling a rod to a bone anchor, the coupling device comprising:
a receiving part configured to receive a head of the bone anchor, the receiving part having a first end and a second end, a central axis that extends between the first end and the second end, and two legs at the first end that define a recess for receiving the rod, wherein the recess extends along a longitudinal axis that is transverse to the central axis, and wherein sides of the legs are recessed relative to an envelope defined by an outer surface of the receiving part such that the width of the legs is narrowed in a circumferential direction around the central axis; and a monolithic pressure member positionable at least partially in the receiving part to exert pressure on an inserted head, the pressure member comprising a rod support surface for supporting the rod and an arm having a free end that is configured to be located at a different axial position than the entire rod support surface; wherein when the pressure member is assembled with the receiving part, at least part of the arm of the pressure member is positioned outside a corresponding one of the legs of the receiving part and extends at least partially into the recessed region on the side of the corresponding one of the legs, while being aligned with the corresponding one of the

Assignees

• Biedermann Technologies Gmbh

Inventors

• Biedermann Timo
• Fischer Bernd

Classifications

• A61B2017/00477

  Coupling (A61B2017/0046 takes precedence) · CPC title

• A61B17/8625

  Shanks, i.e. parts contacting bone tissue · CPC title

• A61B17/8605

  Heads, i.e. proximal ends projecting from bone · CPC title

• A61B17/7032 Primary

  Screws or hooks with U-shaped head or back through which longitudinal rods pass · CPC title

• A61B17/7086

  Rod reducers, i.e. devices providing a mechanical advantage to allow a user to force a rod into or onto an anchor head other than by means of a rod-to-bone anchor locking element; rod removers · CPC title