Interspinous spacer devices for dynamic stabilization of degraded spinal segments

Patent metadata

Field	Value
Publication number	US-9603633-B2
Application number	US-201414577906-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Feb 2, 2011
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

An interspinous spacer device for the treatment of high-grade spinal disorders is disclosed herein. The interspinous spacer device includes a sliding rod and a base that contains a curved internal track that limits the range of motion and center of rotation of the spinal segments stabilized using the device to the physiological levels of a nondegraded spinal segment.

First claim

What is claimed is:

1. An implantable interspinous spacer for implantation at an implantation site between a cranial spinous process and a caudal spinous process, each spinous process extending from a respective vertebral body of a spinal column of vertebral bodies, the spinal column including an anterior-posterior center that is anterior the implantation site, the implantable interspinous spacer comprising:
a first element comprising:
a first anchor structure configured to anchor to a first of the cranial spinous process or the caudal spinal process; and
a body operably coupled to the first anchor structure, the body comprising an outer surface and an internal track surrounded by the outer surface, the internal track comprising a first sliding surface extending cranial-caudal when the implantable interspinous spacer is implanted at the implantation site; and
a second element comprising:
a second anchor structure configured to anchor to a second of the cranial spinous process or the caudal spinous process; and
a retaining plate operably coupled to the second anchor structure and configured to be retained within, and prevent withdrawal from, the internal track of the body, the retaining plate comprising a second sliding surface configured to slidingly displace along the first sliding surface when the implantable interspinous spacer is implanted at the implantation site;
wherein the first sliding surface includes a radius of curvature that is generally equal to a distance extending between the anterior-posterior center and the implantation site.

2. The implantable interspinous spacer of claim 1 , wherein a curvature direction of the first sliding surface is such that, when the implantable interspinous spacer is implanted at the implantation site, a center of rotation associated with the implantation of the implantable interspinous spacer is created at the anterior-posterior center.

3. The implantable interspinous spacer of claim 2 , wherein the implantable interspinous spacer is configured such that an extension-retraction range of movement resulting from the implantation of the implantable interspinous spacer at the implantation site corresponds to a rotation about the center of rotation of approximately eight degrees.

4. The implantable interspinous spacer of claim 1 , wherein the radius of curvature is approximately 50 mm.

5. The implantable interspinous spacer of claim 1 , wherein the first sliding surface is at least part of an anterior sliding surface.

6. The implantable interspinous spacer of claim 5 , wherein the internal track further comprises another sliding surface posterior the first sliding surface and also extending cranial-caudal when the implantable interspinous spacer is implanted at the implantation site, and the retaining plate further comprises another sliding surface posterior the second sliding surface, the other sliding surface of the retaining plate being configured to slidingly displace along the other sliding surface of the internal track when the implantable interspinous spacer is implanted at the implantation site.

7. The implantable interspinous spacer of claim 1 , wherein the first element is a caudal element and the first anchor structure is configured to anchor to the caudal spinous process, and the second element is a cranial element and the second anchor structure is configured to anchor to the cranial spinous process.

8. The implantable interspinous spacer of claim 1 , wherein at least one of the first anchor structure or second anchor structure is configured to receive and wrap around the cranial spinous process or the caudal spinous process.

9. The implantable interspinous spacer of claim 1 , wherein at least one of the first anchor structure or second anchor structure comprises opposed side members joined together by, and extending away from, another member, wherein the associated cranial spinous process or the caudal spinous process is received between the opposed side members in the course of being anchored to the at least one of the first anchor structure or the second anchor structure.

10. The implantable interspinous spacer of claim 1 , wherein a cranial-caudal displacement distance of the second sliding surface relative to the first sliding surface is limited to approximately 3.5 mm.

11. The implantable interspinous spacer of claim 1 , wherein a cranial-caudal length of the first sliding surface is approximately 7 mm.

12. The implantable interspinous spacer of claim 11 , wherein a cranial-caudal length of the second sliding surface is approximately 3.5 mm.

13. The implantable interspinous spacer of claim 1 , wherein the internal track comprises a curved track arrangement that includes the first sliding surface.

14. The implantable interspinous spacer of claim 1 , wherein the first sliding surface and the first anchor structure are of a unitary construction relative to each other in forming the first element.

15. The implantable interspinous spacer of claim 1 , wherein a cranial-caudal length of the first sliding surface of the internal track and a cranial-caudal length of the second sliding surface equal to a thickness of the retaining plate determine a maximum extension-retraction range of movement of the implantable interspinous spacer when implanted at the implantation site.

16. A method of treating a spinal condition employing an implantable interspinous spacer for implantation at an implantation site between a cranial spinous process and a caudal spinous process, each spinous process extending from a respective vertebral body of a spinal column of vertebral bodies, the spinal column including an anterior-posterior center that is anterior the implantation site, the method comprising:
anchoring a first anchor structure of the implantable interspinous spacer to a first of the cranial spinous process or the caudal spinal process; and
anchoring a second anchor structure of the implantable interspinous spacer to a second of the cranial spinous process or the caudal spinal process;
wherein the implantable interspinous spacer comprises:
a first element comprising:
the first anchor structure; and
a body operably coupled to the first anchor structure, the body comprising an outer surface and an internal track surrounded by the outer surface, the internal track comprising a first sliding surface extending cranial-caudal when the implantable interspinous spacer is implanted at the implantation site; and

a second element comprising:
the second anchor structure; and
a retaining plate operably coupled to the second anchor structure and configured to be retained within, and prevent withdrawal from, the internal track of the body, the retaining plate comprising a second sliding surface configured to slidingly displace along the first sliding surface when the implantable interspinous spacer is implanted at the implantation site;

wherein the first sliding surface includes a radius of curvature that is generally equal to a distance extending between the anterior-posterior center and the implantation site.

17. The method of claim 16 , wherein the first element is a caudal element and the first anchor structure is configured to anchor to the caudal spinous process, and the second element is a cranial element and the second anchor structure is configured to anchor to the cranial spinous process.

18. The method of claim 16 , wherein the first anchor structure is configured to receive and wrap around the caudal spinous process, and the second anchor structure is configured to receive and wrap around the cranial spinous proce

Assignees

• Univ Colorado State Res Found

Inventors

• Puttlitz Christian M
• Gadomski Benjamin C

Classifications

• A61B17/7067

  Devices bearing against one or more spinous processes and also attached to another part of the spine; Tools therefor · CPC title

• A61B17/7032

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

• A61B17/7038 Primary

  to a different extent in different directions, e.g. within one plane only · CPC title

• A61B17/7071

  Implants for expanding or repairing the vertebral arch or wedged between laminae or pedicles; Tools therefor · CPC title

• A61B17/7055

  connected to sacrum, pelvis or skull · CPC title