Coupling assembly and polyaxial bone anchoring device comprising the same

Patent metadata

Field	Value
Publication number	US-2016166288-A1
Application number	US-201514964444-A
Country	US
Kind code	A1
Filing date	Dec 9, 2015
Priority date	Dec 10, 2014
Publication date	Jun 16, 2016
Grant date	—

Abstract

A coupling assembly for coupling a rod to a bone anchoring element is provided, wherein the coupling assembly ( 4, 4′ ) comprises
a receiving part ( 5, 5′ ) having a first end ( 5 a ), a second end ( 5 b ), a central axis (C) extending through the first end ( 5 a ) and second end ( 5 b ), an accommodation space ( 54 ) for accommodating a head ( 3, 3′ ) of an anchoring element ( 1, 1′ ), the accommodation space having an opening ( 55 ) at the second end ( 5 b ) sized so as to permit the insertion of a head ( 3, 3′ ) and a bore ( 51 ) extending from the accommodation space to the first end ( 5 a ), and a recess ( 52 ) for receiving a rod ( 100 ), and a retainer element ( 6 ) configured to be positioned at least partially in the accommodation space ( 54 ) and being radially expandable and/or compressible so as to allow retaining a head ( 3, 3′ ) which is inserted through the opening ( 55 ).

The retainer element ( 6 ) is held in position adjacent the opening ( 55 ) by an engagement structure ( 56 ) provided at or in the accommodation space ( 54 ).
The coupling assembly further comprises a locking element ( 7, 7′ ), which is configured to be arranged at least partially in the accommodation space ( 54 ), the locking element ( 7, 7′ ) being movable from a first position, in which the retainer element ( 6 ) is allowed to expand and release an inserted head ( 3, 3′ ), to a second position, in which radial expansion of the retainer element ( 6 ) is hindered so as to prevent release of an inserted head ( 3, 3′ ).
When the locking element ( 7, 7′ ) is in the second position, a head ( 3, 3′ ) of an anchoring element ( 1, 1′ ) can be locked by exertion of a pressure force directly onto the head ( 3, 3′ ) such as to press the head against the retainer element ( 6 ).

First claim

What is claimed is:

1 . A coupling assembly for coupling a rod to a bone anchoring element, the coupling assembly ( 4 , 4 ′) comprising:
a receiving part ( 5 , 5 ′) having a first end ( 5 a ), a second end ( 5 b ), a central axis (C) extending through the first end ( 5 a ) and second end ( 5 b ), an accommodation space ( 54 ) for accommodating a head ( 3 , 3 ′) of an anchoring element ( 1 , 1 ′), the accommodation space having an opening ( 55 ) at the second end ( 5 b ) sized so as to permit the insertion of a head ( 3 , 3 ′) and a bore ( 51 ) extending from the accommodation space to the first end ( 5 a ), and a recess ( 52 ) for receiving a rod ( 100 ),
a retainer element ( 6 ) configured to be positioned at least partially in the accommodation space ( 54 ) and being radially expandable and/or compressible so as to allow retaining a head ( 3 , 3 ′) which is inserted through the opening ( 55 );
wherein the retainer element ( 6 ) is held in position adjacent the opening ( 55 ) by an engagement structure ( 56 ) provided at or in the accommodation space ( 54 );
a locking element ( 7 , 7 ′), which is configured to be arranged at least partially in the accommodation space ( 54 ), the locking element ( 7 , 7 ′) being movable from a first position, in which the retainer element ( 6 ) is allowed to expand and release an inserted head ( 3 , 3 ′), to a second position, in which radial expansion of the retainer element ( 6 ) is hindered so as to prevent release of an inserted head ( 3 , 3 ′);
wherein, when the locking element ( 7 , 7 ′) is in the second position, a head ( 3 , 3 ′) of an anchoring element ( 1 , 1 ′) can be locked by exertion of a pressure force directly onto the head ( 3 , 3 ′) against the retainer element ( 6 ).

2 . The coupling assembly of claim 1 , wherein the retainer element ( 6 ) defines an open or closed ring-shape.

3 . The coupling assembly of claim 1 , wherein the retainer element ( 6 ) includes one or more slits ( 63 ) in order to allow the retainer element ( 6 ) to be expanded and/or compressed.

4 . The coupling assembly of claim 1 , wherein the retainer element ( 6 ) includes:
a first engagement portion ( 61 ) for engagement with the engagement structure ( 56 ) provided at or in the accommodation space ( 54 ) of the receiving part ( 5 , 5 ′) such as to hold the retainer element ( 6 ) in position; and a second engagement portion ( 62 ) for engagement by the locking element ( 7 , 7 ′) when moved in to the second position, such as to prevent the retainer element ( 6 ) from expansion.

5 . The coupling assembly of claim 4 , wherein the first engagement portion ( 62 ) of the retainer element ( 6 ) has an annular shape or annular segment shape.

6 . The coupling assembly of claim 4 , wherein the engagement structure ( 56 ) provided at or in the accommodation space ( 54 ) is a recess formed at an inner wall of the accommodation space ( 54 ).

7 . The coupling assembly of claim 6 , wherein the recess has a shape of an annular groove.

8 . The coupling assembly of claim 4 , wherein the second engagemenmt portion of the retainer element ( 6 ) has a cylindrical or conical shape which is coaxial with the central axis (C) when the retainer element ( 6 ) is held in position in the accommodation space ( 54 ).

9 . The coupling assembly of claim 1 , wherein the retainer element ( 6 ) further includes: a hollow spherical segment-shaped portion ( 64 ) configured to receive the head ( 3 , 3 ′) therein.

10 . The coupling assembly of claim 4 , wherein the locking element ( 7 , 7 ′) comprises:
an outer at least partially cylindrical surface ( 71 ) dimensioned to be in sliding engagement with an inner wall of the accommodation space ( 54 ) when being received therein at least between the first and second positions; and
an inner cavity ( 72 ) including a recess ( 73 ) having an inner wall ( 74 ) configured to engage the second engagement portion ( 62 ) of the retainer element ( 6 ), which prevents the retainer element ( 6 ) from expansion when the locking element ( 7 , 7 ′) is in the seond position.

11 . The coupling assembly of claim 10 , wherein the locking element ( 7 ) is a pressure element which is arranged to receive and transfer a pressure force from a fixation element ( 9 ), which is attached to the bore ( 51 ) of the receiving part ( 5 ) at the first end ( 5 a ), and/or a rod ( 100 ), which is received in the recess ( 52 ) of the receiving part ( 5 ), towards the head ( 3 ) in order to tight lock the head ( 3 ).

12 . The coupling assembly of claim 11 , wherein the inner cavity ( 72 ) of the locking element ( 7 ) further comprises an inner hollow spherical segment-shaped recess ( 74 ) configured to receive the head ( 3 , 3 ′).

13 . The coupling assembly of claim 1 , wherein the locking element ( 7 , 7 ′) comprises a rod receiving portion ( 75 ) configured to receive a rod ( 100 ).

14 . The coupling assembly of claim 1 , wherein the locking element ( 7 , 7 ′) comprises an first engagement shoulder ( 77 ) configured to engage a second engagement shoulder ( 57 ) provided in the bore ( 51 ) or accommodation space ( 54 ), when the locking element ( 7 , 7 ′) is in the second position.

15 . The coupling assembly of claim 1 , wherein the retainer element ( 6 ) and/or the locking element ( 7 , 7 ′) are configured such as to be inserteable into the bore ( 51 ) and accommodation space ( 54 ) of the receiving part ( 5 , 5 ′) from the first end ( 5 a ).

16 . A polyaxial bone anchoring device comprising
a bone anchoring element ( 1 , 1 ′) having shank ( 2 ) for anchoring to bone and a head ( 3 , 3 ′), and a coupling assembly ( 4 , 4 ′) according to claim 1 .

17 . A polyaxial bone anchoring device of claim 16 , wherein
the head ( 3 ′) of the bone anchoring element comprises a spherical end surface with an engagement recess ( 31 ′) for a driver wherein the recess comprises a plurality of wing portions ( 34 ) that extend in a spiral-like manner from a center point of the free end surface; and the retainer element ( 6 ′) and the locking element ( 7 ′) are shaped such that the head ( 3 ′) can partially extend therethrough in order to be directly engaged by an inserted rod ( 100 ).

Assignees

• Biedermann Technologies Gmbh

Inventors

• Biedermann Lutz
• Fischer Bernd
• Matthis Wilfried

Classifications

• A61B17/7037 Primary

  wherein pivoting is blocked when the rod is clamped · CPC title

• A61B2017/00477

  Coupling (A61B2017/0046 takes precedence) · CPC title

• A61B17/7032 Primary

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

• A61B2017/564

  Methods for bone or joint treatment · CPC title