Extension device for a bone anchor, in particular for minimally invasive surgery

Patent metadata

Field	Value
Publication number	US-9492209-B2
Application number	US-201414565365-A
Country	US
Kind code	B2
Filing date	Dec 9, 2014
Priority date	Dec 9, 2013
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

An extension device for a bone anchor is provided, where the bone anchor includes an anchoring section for anchoring to a bone and a receiving part connected to the anchoring section. The receiving part includes a central axis and a channel for receiving a rod, where sidewalls of the channel form two free legs. The extension device includes a first sleeve with a first sleeve axis that is coaxial with the central axis, where the first sleeve is configured to be detachably coupled to the receiving part. The extension device includes a second sleeve with a second sleeve axis, where the second sleeve is positioned within the first sleeve. The first sleeve is configured to be coupled to the receiving part to inhibit translational movement of the first sleeve relative to the receiving part along the central axis. The second sleeve is configured to be coupled to the receiving part to hinder or inhibit rotational movement of the second sleeve relative to the receiving part and the second sleeve is connected to the first sleeve through a coupling member that is configured to advance in the first sleeve together with the second sleeve in an axial direction.

First claim

The invention claimed is:

1. An extension device for a bone anchor, wherein the bone anchor comprises an anchoring section for anchoring to a bone and a receiving part connected to the anchoring section, the receiving part comprising a central axis and a channel for receiving a rod, the extension device comprising:
a first sleeve having a first sleeve axis, wherein the first sleeve is configured to be detachably coupled to the receiving part;
a second sleeve configured to contact the receiving part when the second sleeve is positioned in the first sleeve; and
a coupling member configured to connect the first sleeve to the second sleeve, wherein when the coupling member is connected to the first sleeve, the entire coupling member is in the first sleeve;
wherein the first sleeve is configured to contact the receiving part to restrict translational movement of the first sleeve relative to the receiving part along the central axis,
wherein the second sleeve is configured to contact the receiving part to restrict rotational movement of the second sleeve relative to the receiving part, and
wherein the coupling member is configured to axially advance in the first sleeve together with the second sleeve along the first sleeve axis.

2. The extension device of claim 1 ,
wherein the first sleeve comprises a first end, an opposite second end, and an attachment structure adjacent the first end configured to detachably couple to the receiving part,
wherein the coupling member comprises an advancement structure configured to couple the coupling member to the first sleeve, and
wherein when the advancement structure of the coupling member is coupled to the first sleeve, the coupling member and the second sleeve are configured to advance along the first sleeve axis to a given position closer to the first end of the first sleeve.

3. The extension device of claim 2 , wherein the coupling member is a bushing and the advancement structure comprises threads.

4. The extension device of claim 3 , wherein the second sleeve is configured to be coupled to the first sleeve in a rigid manner.

5. The extension device of claim 1 , wherein the coupling member is coupled to the second sleeve such that the coupling member can rotate with respect to the second sleeve.

6. The extension device of claim 1 , wherein the second sleeve comprises an abutment configured to restrict the coupling member from moving axially relative to the second sleeve.

7. A spinal stabilization system for use with minimally invasive surgery comprising a system with at least two bone anchors and an extension device for each bone anchor according to claim 1 .

8. The extension device of claim 1 , wherein at least a portion of the coupling member is configured to be positioned in the second sleeve.

9. The extension device of claim 1 , wherein a rear end of the first sleeve comprises at least one longitudinal slit and a plurality of notches extending from the longitudinal slit for latching with a tool to fix an inserted rod.

10. An extension device system comprising an extension device and a bone anchor,
the bone anchor comprising:
an anchoring section for anchoring to a bone and a receiving part connected to the anchoring section, the receiving part comprising a central axis and a channel for receiving a rod, wherein sidewalls of the channel form two free legs,

the extension device comprising:
a first sleeve having a first sleeve axis, wherein the first sleeve is configured to be detachably coupled to the receiving part;
a second sleeve having a second sleeve axis, wherein the second sleeve is configured to be positioned in the first sleeve with the second sleeve axis coaxial with the first sleeve axis; and
a coupling member configured to couple to the second sleeve and configured to connect the first sleeve to the second sleeve, wherein when the coupling member is coupled to the second sleeve, the coupling member is restricted from moving axially relative to the second sleeve along the second sleeve axis;
wherein the first sleeve is configured to couple to the receiving part and prevent translational movement of the first sleeve relative to the receiving part along the central axis,
wherein the second sleeve remains movable along the central axis relative to the first sleeve when the first sleeve is coupled to the receiving part and prevented from translational movement relative to the receiving part,
wherein the second sleeve is configured to be coupled to the receiving part to restrict rotational movement of the second sleeve relative to the receiving part; and
wherein when the coupling member is connected to the first sleeve, the entire coupling member is in the first sleeve.

11. The extension device of claim 10 , wherein the first sleeve comprises a protrusion and/or a recess at an inner surface thereof that is configured to engage a complementary structure at an outer surface of the receiving part to provide a form-fit connection between the first sleeve and the receiving part.

12. The extension device of claim 11 , wherein the protrusion and/or recess at the first sleeve and the complementary structure at the receiving part are shaped to restrict axial movement of the first sleeve relative to the receiving part along the central axis of the receiving part.

13. The extension device of claim 11 , wherein the protrusion and/or recess of the first sleeve is configured to engage the complementary structure of the receiving part to restrict rotational movement of the first sleeve relative to the receiving part about the central axis.

14. The extension device of claim 10 , wherein the second sleeve comprises a protrusion and/or a recess at a surface thereof that is configured to engage a complementary structure at a surface of the receiving part to provide a form-fit connection between the second sleeve and the receiving part.

15. The extension device of claim 10 , wherein the second sleeve comprises a substantially flat surface portion that is configured to engage a substantially flat surface portion of the receiving part such that friction between the surface portions is generated when the receiving part is rotated relative to the second sleeve.

16. The extension device of claim 10 , wherein the first sleeve comprises a first end and an opposite second end and wherein the first sleeve comprises a longitudinal recess that extends in an axial direction and that is open to the second end, wherein a width of the recess of the first sleeve is at least as wide as a width of the channel of the receiving part for receiving the rod.

17. The extension device of claim 10 , wherein the second sleeve comprises a first end and an opposite second end and wherein the second sleeve comprises a longitudinal recess that extends in an axial direction and that is open to the second end, wherein a width of the recess of the second sleeve is at least as wide as a width of the channel of the receiving part for receiving the rod.

18. The extension device of claim 10 , wherein the first sleeve comprises at least one longitudinally extending rib configured to engage a corresponding longitudinally extending groove in the receiving part to restrict rotational movement of the receiving part relative to the first sleeve about the central axis.

19. The extension device of claim 10 , wherein the first sleeve comprises a circumferentially extending rib configured to engage a circumferentially extending groove of the receiving part to restrict axial movement of the first sleeve relative to the receiving part along the ce

Assignees

• Biedermann Technologies Gmbh

Inventors

• Biedermann Timo
• Dannecker Berthold

Classifications

• A61B17/00234

  for minimally invasive surgery (A61B17/0218, A61B17/0469, A61B17/12013, A61B17/1285, A61B17/29, A61B17/320016 take precedence) · CPC title

• A61B17/7032

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

• A61B17/7091

  for applying, tightening or removing longitudinal element-to-bone anchor locking elements, e.g. caps, set screws, nuts or wedges · CPC title

• A61B17/7085 Primary

  for insertion of a longitudinal element down one or more hollow screw or hook extensions, i.e. at least a part of the element within an extension has a component of movement parallel to the extension's axis · CPC title

• A61B17/708

  with tubular extensions coaxially mounted on the bone anchors · CPC title