Bone stabilization member with bone screw retention mechanism

Patent metadata

Field	Value
Publication number	US-9937056-B2
Application number	US-201615210615-A
Country	US
Kind code	B2
Filing date	Jul 14, 2016
Priority date	Jul 27, 2012
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

A spinal implant for stabilizing first and second vertebrae. The spinal implant includes an intervertebral spacer and a bone stabilization member configured to be coupled to the intervertebral spacer. The bone stabilization member includes a plurality of bone screw openings and a plurality of bone screws extendable through the bone screw openings to secure the bone stabilization member to the vertebrae. A retention member, which is slidably coupled to the bone stabilization member, is linearly slidable between a first position and a second position while coupled to the bone stabilization member. In the first position, each of the bone screws is permitted to be inserted into the bone screw openings, and in the second position the retention member at least partially covers each of the bone screw openings to prevent a bone screw from backing out of the respective bone screw opening.

First claim

What is claimed is:

1. A spinal implant positionable between vertebral bodies, the spinal implant comprising:
an intervertebral spacer positionable between a first vertebra and a second vertebra;
a bone stabilization member coupled to the intervertebral spacer, the bone stabilization member including a first bone screw opening and a second bone screw opening;
a first bone screw extendable through the first bone screw opening to secure the bone stabilization member to the first vertebra;
a second bone screw extendable through the second bone screw opening to secure the bone stabilization member to the second vertebra;
a retention member coupled to the bone stabilization member, the retention member movable between a first position and a second position, the retention member allowing the first and second bone screws to be received through the first and second bone screw openings, respectively, when the retention member is in the first position, and the retention member preventing the first and second bone screws from exiting the first and second bone screw openings, respectively, when the retention member is in the second position; and
a locking screw coupling the retention member to the bone stabilization member, the locking screw extendable through an elongate opening of the retention member into a threaded bore of the bone stabilization member, the elongate opening having a length greater than a width of the elongate opening, and wherein the locking screw travels along the length of the elongate opening as the locking screw is rotated into the threaded bore which moves the retention member between the first position and the second position.

2. The spinal implant of claim 1 , wherein the retention member includes a protrusion slidably engaged in a slot of the bone stabilization member.

3. The spinal implant of claim 2 , wherein the protrusion is dovetail shaped and the slot is dovetail shaped to mate with the dovetail shape of the protrusion.

4. The spinal implant of claim 1 , wherein the retention member is linearly slidable between the first position and the second position.

5. The spinal implant of claim 1 , wherein the retention member is movable between the first and second position while the locking screw couples the retention member to the bone stabilization member.

6. The spinal implant of claim 1 , wherein the intervertebral spacer has a midplane extending in a superior/inferior direction between lateral sides of the intervertebral spacer;
wherein the first bone screw opening is offset to a first side of the midplane;
wherein the second bone screw opening is offset to a second side of the midplane, opposite the first side; and
wherein the locking screw is located between the first bone screw opening and the second bone screw opening.

7. The spinal implant of claim 6 , wherein the first bone screw angles toward the midplane when extended through the first bone screw opening.

8. The spinal implant of claim 1 , wherein the retention member includes a first tab covering a portion of the second bone screw opening when the retention member is in the second position.

9. The spinal implant of claim 8 , wherein the retention member includes an arcuate edge defining an arcuate cutout portion of the retention member covering a portion of the first bone screw opening when the retention member is in the second position.

10. A spinal implant positionable between vertebral bodies, the spinal implant comprising:
an intervertebral spacer positionable between a first vertebra and a second vertebra, the intervertebral spacer having a midplane that extends in a superior/inferior direction between lateral sides of the intervertebral spacer;
a bone stabilization member coupled to the intervertebral spacer, the bone stabilization member including a first bone screw opening offset to a first side of the midplane and a second bone screw opening offset to a second side of the midplane opposite the first side;
a first bone screw extendable through the first bone screw opening to secure the bone stabilization member to the first vertebra;
a second bone screw extendable through the second bone screw opening to secure the bone stabilization member to the second vertebra; and
a retention member coupled to the bone stabilization member, the retention member including an elongate opening offset to the first side of the midplane, the retention member movable between first and second positions, allowing the first and second bone screws to be received through the bone stabilization member when the retention member is in a first position and preventing the first and second bone screws from exiting the bone stabilization member when the retention member is in a second position.

11. The spinal implant of claim 10 , further comprising a locking screw coupling the retention member to the bone stabilization member.

12. The spinal implant of claim 11 , wherein rotation of the locking screw about a rotational axis causes the retention member to move in a direction generally perpendicular to the rotational axis.

13. The spinal implant of claim 11 , wherein rotation of the locking screw causes the locking screw to travel along the elongate opening of the retention member and interact with a rim of the elongate opening such that when a head of the locking screw is pressed against the rim the retention member moves toward the second position.

14. The spinal implant of claim 10 , wherein the retention member includes a protrusion slidably disposed in a slot of the bone stabilization member.

15. The spinal implant of claim 14 , wherein the protrusion is dovetail shaped and the slot is dovetail shaped to mate with the dovetail shape of the protrusion.

16. The spinal implant of claim 10 , wherein the intervertebral spacer includes first and second channels disposed on the lateral sides; and
wherein the bone stabilization member includes first and second arms engageable with the first and second channels, respectively, to secure the intervertebral spacer to the bone stabilization member.

17. The spinal implant of claim 16 , wherein the first and second channels each include first and second notches, respectively; and
wherein the first and second arms include first and second tangs, respectively, engageable with the first and second notches, respectively, to interlock the bone stabilization member with the intervertebral spacer.

18. The spinal implant of claim 17 , wherein the first and second tangs are flexibly deflectable relative to the first and second arms, respectively.

19. The spinal implant of claim 18 , wherein the first and second tangs are deflectable outward as the first and second arms engage the first and second channels and the first and second tangs return to an equilibrium position as the tangs engage in the notches.

Assignees

• Zimmer Spine Inc

Inventors

• Carlson Daniel
• Mednikov Gregory A
• Morris Eric W

Classifications

• A61F2/4455

  for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages (intervertebral discs A61F2/442) · CPC title

• A61B17/8042

  the additional component being a cover over the screw head · CPC title

• A61B17/7059

  Cortical plates (A61B17/7007, A61B17/7058 take precedence) · CPC title

• A61F2002/305

  Snap connection · CPC title

• A61F2002/30383

  made by laterally inserting a protrusion, e.g. a rib into a complementarily-shaped groove · CPC title