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

Patent metadata

Field	Value
Publication number	US-9956012-B2
Application number	US-201514740228-A
Country	US
Kind code	B2
Filing date	Jun 15, 2015
Priority date	Jun 17, 2014
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

An extension device for a bone anchor is provided, where the bone anchor includes an anchoring section and a receiving part connected to the anchoring section having a central axis. The extension device includes a first sleeve with a first sleeve axis that is coaxial to the central axis of the receiving part and is configured to be coupled to and decoupled from the receiving part. The extension device further includes a second sleeve with a second sleeve axis coaxial to the central axis. The second sleeve is positioned within the first sleeve, is positionable relative to the first sleeve along the central axis, and is configured to be coupled to and decoupled from the receiving part. The extension device also includes a locking member that, in a first configuration, inhibits decoupling of the first sleeve or the second sleeve from the receiving part when the other one of the first sleeve or the second sleeve is coupled to the receiving part.

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 configured to be connected to the anchoring section, the receiving part comprising two legs defining a channel for receiving a rod, the extension device comprising:
a first sleeve having a first end, a second end, and a first sleeve axis extending between the first and second ends, wherein the first end of the first sleeve is configured to be coupled to the receiving part;
a second sleeve positionable at least partially in and movable axially relative to the first sleeve, wherein the second sleeve is configured to be coupled to the receiving part; and
a locking member movable relative to the second sleeve, the locking member having a through bore, wherein the locking member is configured to be connected to the first sleeve at a position closer to the second end of the first sleeve than to the first end of the first sleeve,
wherein the extension device is adjustable between a first configuration wherein the locking member is compressed such that a first portion of the through bore has a first diameter, and a second configuration wherein the locking member is expanded such that the first portion of the through bore has a diameter that is greater than the first diameter;
wherein a distal end of the second sleeve remains entirely inside the first sleeve in the first configuration.

2. The extension device of claim 1 , wherein the locking member is configured to inhibit attachment of a decoupling instrument to the extension device when the locking member is in the first configuration.

3. The extension device of claim 1 , wherein the locking member comprises a spring that is compressible and/or extendible in a radial direction relative to the first sleeve axis.

4. The extension device of claim 1 , wherein the locking member is positionable at least partially inside the second sleeve and comprises a collet positionable at least partially inside the first sleeve.

5. The extension device of claim 1 , wherein the second sleeve is configured to be connected to the first sleeve through a coupling member that is configured to advance together with the second sleeve in an axial direction relative to the first sleeve.

6. The extension device of claim 5 , wherein the coupling member comprises a bushing that is configured to be coupled to the first sleeve by an advancement structure that permits the coupling member to advance with the second sleeve relative to the first sleeve.

7. The extension device of claim 6 , wherein the advancement structure comprises threads on the bushing and on the first sleeve.

8. The extension device of claim 7 , wherein the locking member and the coupling member are formed as a single monolithic part.

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

10. The extension device of claim 5 , wherein the locking member and the coupling member are formed as a single monolithic part.

11. The extension device of claim 1 , further comprising a third sleeve that is selectively connectable to the first sleeve to enlarge an axial length of the extension device and wherein the third sleeve has an inner wall defining a passage sized for insertion of a portion of the first sleeve.

12. The extension device of claim 11 , a pusher and wherein when the portion of the first sleeve is in the third sleeve, the pusher is adjustable between a first position wherein the pusher protrudes into the passage to clamp the first sleeve in the passage, and a second position wherein the pusher is positioned entirely outside of the passage for removing the first sleeve from the passage.

13. The extension device of claim 12 , wherein the third sleeve has two opposite slots for the pusher to extend through, and wherein the pusher has an inner hollow section for the portion of the first sleeve to pass therethrough.

14. The extension device of claim 1 , wherein, when the extension device is adjusted from the second configuration to the first configuration, there is movement of the first sleeve and the locking member relative to each other along a tapered surface at an engagement between the first sleeve and the locking member.

15. The extension device of claim 14 , wherein the tapered surface is on the locking member and the tapering narrows in a direction from the second end of the first sleeve to the first end of the first sleeve.

16. An extension device system comprising:
a bone anchor comprising:
an anchoring section for anchoring to a bone; and
a receiving part connected to or configured to be connected to the anchoring section, the receiving part comprising two legs defining a channel for receiving a rod; and

an extension device for the bone anchor, comprising:
a first sleeve configured to be coupled to the receiving part;
a second sleeve positionable at least partially in and movable relative to the first sleeve, wherein the second sleeve is configured to be coupled to the receiving part; and
a locking member with a through bore, wherein the locking member is configured to be connected to the first sleeve and the second sleeve for moving the second sleeve axially relative to the first sleeve;

wherein when the first sleeve is coupled to the receiving part, the extension device is adjustable between a first configuration wherein the second sleeve is axially spaced apart from the receiving part and the through bore of the locking member has a first minimum diameter, and a second configuration wherein the second sleeve contacts the receiving part and the locking member is radially compressed such that the through bore of the locking member has a diameter smaller than the first minimum diameter.

17. The extension device system of claim 16 , wherein each of the first sleeve and the second sleeve is configured to be coupled to the receiving part via a form-fit engagement.

18. The extension device system of claim 16 , wherein the first sleeve is configured to be coupled to the receiving part via a form-fit engagement, and wherein the second sleeve is configured to be coupled to the receiving part via a frictional engagement.

19. The extension device system of claim 16 , further comprising a second bone anchor and a second extension device.

20. The extension device system of claim 16 , wherein in the second configuration, the locking member permits decoupling of one of the first sleeve or the second sleeve from the receiving part when the other one of the first sleeve or the second sleeve is decoupled from the receiving part.

21. The extension device system of claim 16 , wherein the locking member inhibits decoupling of the first sleeve when the second sleeve is coupled to the receiving part.

22. The extension device system of claim 16 , wherein in the first configuration, an abutment between the first sleeve and the receiving part restricts axial movement of the first sleeve relative to the receiving part.

23. The extension device system of claim 16 , further comprising a third sleeve that is selectively connectable to the first sleeve to enlarge an axial length of the extension device and wherein the third sleeve has an inner wall defining a passage sized for insertion of a portion of the first sleeve.

24. The extension device system of claim 23 , wherein th

Assignees

• Biedermann Technologies Gmbh

Inventors

• Biedermann Timo
• Dannecker Berthold

Classifications

• A61B17/7032

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

• A61B17/7076 Primary

  for driving, positioning or assembling spinal clamps or bone anchors specially adapted for spinal fixation · CPC title

• A61B17/708 Primary

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

• A61B17/8863

  Apparatus for shaping or cutting osteosynthesis equipment by medical personnel · CPC title

• A61B17/8875

  Screwdrivers, spanners or wrenches · CPC title