Polyaxial bone anchoring device

Patent metadata

Field	Value
Publication number	US-12514619-B2
Application number	US-202218056838-A
Country	US
Kind code	B2
Filing date	Nov 18, 2022
Priority date	Apr 15, 2021
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

A polyaxial bone anchoring device includes a receiving part with a rod receiving portion defining a recess for receiving a rod, and a head receiving portion with a wall that defines an accommodation space for accommodating a head of an anchoring element, and a locking member positionable at least partially around the head receiving portion and movable from a first position where the head can pivot in the accommodation space to a second position where an angular position of the head is locked. The wall of the head receiving portion further defines at least one cavity in communication with the accommodation space that reduces a radial thickness of at least part of the wall located between the accommodation space and the locking member, and at least part of the cavity is separated radially from the accommodation space by a portion of the wall.

First claim

What is claimed is:

1 . A polyaxial bone anchoring device comprising:
an anchoring element comprising a head and a shank for anchoring in bone; a receiving part having a first end, a second end below the first end, and a central axis that extends through the first and second ends, the receiving part comprising a rod receiving portion at the first end defining a recess for receiving a rod, and a head receiving portion at the second end defining a seat that is directly engageable with the head of the anchoring element to hold the head in the head receiving portion, wherein at least one slit extends axially upwardly from the second end of the receiving part into the head receiving portion to an uppermost end that is positioned axially lower on the receiving part than a bottom of the recess to facilitate compression of the head receiving portion; and a locking member positionable at least partially around the receiving part; wherein when the head is held in the seat and the locking member is around the receiving part, the uppermost end of the at least one slit is spaced apart from the head and is positioned farther radially from the central axis than a widest region of the head extends away from the central axis, while the locking member is movable from a first position where the head is pivotable in the seat to a second position where the locking member applies an inward pressure against the head receiving portion to compress the head receiving portion and lock an angular position of the head relative to the receiving part.

2 . The polyaxial bone anchoring device of claim 1 , wherein the second end of the receiving part defines an opening for inserting the head into the receiving part, and wherein the head receiving portion is expandable to facilitate insertion of the head into the receiving part.

3 . The polyaxial bone anchoring device of claim 2 , wherein the receiving part and/or the locking member comprises a holding structure for temporarily holding the locking member at an insertion position where the head receiving portion is expandable for inserting the head of the anchoring element into the receiving part.

4 . The polyaxial bone anchoring device of claim 3 , wherein when the locking member is mounted to the receiving part, the locking member is movable to the insertion position by rotating the locking member around the central axis.

5 . The polyaxial bone anchoring device of claim 1 , wherein the at least one slit comprises a plurality of slits that form flexible wall sections of the head receiving.

6 . The polyaxial bone anchoring device of claim 1 , wherein part of at least one of an outer surface of the head receiving portion or an inner surface of the locking member is tapered to facilitate application of the inward pressure by the locking member on the head receiving portion.

7 . The polyaxial bone anchoring device of claim 1 , wherein the locking member forms a closed ring positionable around the head receiving portion.

8 . The polyaxial bone anchoring device of claim 1 , wherein the locking member is selectively mountable to the receiving part from the first end or from the second end.

9 . The polyaxial bone anchoring device of claim 1 , wherein the receiving part and/or the locking member comprises a holding structure for temporarily holding the locking member at a pre-locking position where the head is pivotable in the receiving part but is prevented from removal from the receiving part.

10 . The polyaxial bone anchoring device of claim 1 , wherein a cavity extends between and spaces apart the head from an inner surface of the receiving part through which the uppermost end of the at least one slit extends.

11 . The polyaxial bone anchoring device of claim 1 , wherein the receiving part is monolithic, and wherein another portion of the receiving part extends between and spaces apart the head from an inner surface of the receiving part through which the uppermost end of the at least one slit extends.

12 . The polyaxial bone anchoring device of claim 1 , further comprising a pressure member movable axially in the receiving part to directly engage and exert a downward pressure on the head to clamp the head in the receiving part, wherein the pressure member extends between and spaces apart the head from an inner surface of the receiving part through which the uppermost end of the at least one slit extends.

13 . A polyaxial bone anchoring device comprising:
a monolithic receiving part having a first end, a second end below the first end, and a central axis that extends through the first and second ends, the receiving part comprising a rod receiving portion at the first end defining a recess for receiving a rod, and a head receiving portion at the second end defining an accommodation space for accommodating a head of an anchoring element and comprising a downwardly facing head contacting surface that extends uninterruptedly for an entire circumference around the central axis for directly contacting the head, wherein at least one slit extends axially upwardly from the second end of the receiving part into the head receiving portion to an axial position that is higher on the receiving part than at least part of the head contacting surface to facilitate compression of the head receiving portion; and a locking member positionable at least partially around the receiving part and movable from a first position where an inserted head is pivotable in the accommodation space, to a second position where the locking member applies an inward pressure against the head receiving portion to compress the head receiving portion and lock an angular position of the inserted head in the accommodation space.

14 . The polyaxial bone anchoring device of claim 13 , wherein the second end of the receiving part defines an opening for inserting the head into the accommodation space, and wherein the head receiving portion is expandable to facilitate insertion of the head into the accommodation space.

15 . The polyaxial bone anchoring device of claim 13 , wherein the at least one slit comprises a plurality of slits that form flexible wall sections of the head receiving portion.

16 . The polyaxial bone anchoring device of claim 13 , wherein a pressure member is monolithically formed with the receiving part and is movable axially in the accommodation space, and wherein the downwardly facing head contacting surface is formed on the pressure member.

17 . A polyaxial bone anchoring device comprising:
a receiving part having a first end, a second end below the first end, and a central axis that extends through the first and second ends, the receiving part comprising a rod receiving portion at the first end defining a recess for receiving a rod, and a head receiving portion at the second end defining an accommodation space for accommodating a head of an anchoring element; and a pressure member movable axially in the accommodation space, the pressure member having an upper end and a lower end, and comprising a downwardly facing surface at the lower end that extends uninterruptedly for an entire circumference around the central axis to directly engage and exert a downward pressure on an inserted head to clamp the head in the accommodation space; wherein the pressure member is monolithically formed with the receiving part, with a connection portion that extends between the receiving part and a portion of the pressure member that is closer to the lower end than to the upper end.

18 . The polyaxial bone anchoring device of claim 17 , further comprising a locking m

Assignees

• Biedermann Technologies Gmbh

Inventors

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

Classifications

• A61B17/7091

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

• A61B17/7082

  for driving, i.e. rotating, screws or screw parts specially adapted for spinal fixation, e.g. for driving polyaxial or tulip-headed screws · CPC title

• A61B17/7008

  with parts of, or attached to, the longitudinal elements, bearing against an outside of the screw or hook heads, e.g. nuts on threaded rods (A61B17/7007 takes precedence) · CPC title

• A61B17/6475

  the connecting rod being threaded · CPC title

• A61B17/7035

  Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other · CPC title