Bone stabilization member with bone screw retention mechanism

Patent metadata

Field	Value
Publication number	US-9414937-B2
Application number	US-201414332851-A
Country	US
Kind code	B2
Filing date	Jul 16, 2014
Priority date	Jul 27, 2012
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

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 for positioning between a first vertebra and a second vertebra, the spinal implant comprising:
an intervertebral spacer configured for placement between a vertebral body of the first vertebra and a vertebral body of the second vertebra;
a bone stabilization member configured to be coupled to the intervertebral spacer;
the bone stabilization member including a first bone screw opening, a second bone screw opening, and a third 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 third bone screw extendable through the third 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 linearly slidable between a first position and a second position while coupled to the bone stabilization member; and
a locking screw coupling the retention member to the bone stabilization member;
wherein in the first position the first, second and third bone screws are permitted to be inserted into the first, second and third bone screw openings, respectively, and in the second position the retention member prevents the first, second and third bone screws from being removed from the first, second and third bone screw openings.

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 1 , wherein the locking screw extends 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;
wherein the locking screw travels along the length of the elongate opening as the locking screw is rotated into the threaded bore to move the retention member from the first position to the second position.

4. 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 located between the second bone screw opening and the third bone screw opening;
wherein the first bone screw opening is offset to a first side of the midplane; and
wherein the locking screw is offset to a second side of the midplane opposite the first side.

5. The spinal implant of claim 1 , wherein the first bone screw opening is located between the second bone screw opening and the third bone screw opening;
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 one side of the midplane; and
wherein the first bone screw angles toward the midplane when extended through the first bone screw opening.

6. The spinal implant of claim 1 , wherein the retention member includes a first tab configured to at least partially cover the second bone screw opening in the second position and a second tab configured to at least partially cover the third bone screw opening in the second position.

7. The spinal implant of claim 6 , wherein the retention member includes an arcuate edge defining an arcuate cutout portion of the retention member configured to at least partially cover the first bone screw opening in the second position.

8. A spinal implant for positioning between a first vertebra and a second vertebra, the spinal implant comprising:
an intervertebral spacer configured for placement between a vertebral body of the first vertebra and a vertebral body of the second vertebra;
a bone stabilization member configured to be coupled to the intervertebral spacer; the bone stabilization member including a first bone screw opening, a second bone screw opening, and a third 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 third bone screw extendable through the third 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 while coupled to the bone stabilization member; and
a locking screw coupling the retention member to the bone stabilization member, 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;
wherein the first bone screw opening is located between the second bone screw opening and the third bone screw opening;
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 one side of the midplane; and
wherein the first bone screw angles toward the midplane when extended through the first bone screw opening.

9. The spinal implant of claim 8 , wherein in the second position the retention member prevents at least one of the first, second and third bone screws from being removed from bone stabilization member.

10. The spinal implant of claim 8 , wherein rotation of the locking screw causes the locking screw to travel along an elongate opening of the retention member.

11. The spinal implant of claim 10 , wherein the locking screw interacts 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.

12. The spinal implant of claim 8 , wherein the retention member includes a protrusion slidably disposed in a slot of the bone stabilization member.

13. The spinal implant of claim 12 , wherein the protrusion is dovetail shaped and the slot is dovetail shaped to mate with the dovetail shape of the protrusion.

14. The spinal implant of claim 8 , wherein the retention member is configured to simultaneously cover at least a portion of each of the first, second and third bone screw openings.

Assignees

• Zimmer Spine Inc

Inventors

• Carlson Daniel A
• Mednikov Gregory A
• Morris Eric W

Classifications

• A61B17/7059

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

• 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

• A61F2002/305

  Snap connection · CPC title

• A61F2002/30787

  inclined obliquely with respect to each other · CPC title