Laminoplasty cage

• US 20040153155A1
• Filed: 01/22/2004
• Published: 08/05/2004
• Est. Priority Date: 09/30/2002
• Status: Active Grant

• Current Assignee: Depuy Acromed Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Acromed Incorporated (Johnson & Johnson)
• Inventors: Michielli, Michael Carl, Chung, Jae-Yoon
• Granted Patent: US 6,997,953 B2
• Time in Patent Office: Days
• US Class Current: 623/17.11
• CPC Class Codes: A61B 17/7071 Implants for expanding or repairing the vertebral arch or wedged between laminae or pedicles; Tools therefor
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2002/3008 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2002/30578 having apertures, e.g. for receiving fixation screws
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/448 comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: Y10S 606/907 Composed of particular material or coated
• CPC Class Codes: Y10S 606/91 Polymer
• CPC Class Codes: Y10S 606/912 Radiolucent material

Abstract

A medical implant device for use in spinal surgery, and more preferably for use in laminoplasty surgery is provided. The implant is a cage-like member having a generally hollow, elongate body with open ends. The implant is formed from a generally hollow, elongate body having four sides: opposed cephalad and caudal sides, and opposed posterior and anterior sides adjacent to the cephalad and caudal sides. The four sides extend along a longitudinal axis, and define an inner lumen extending between opposed first and second open ends.

Claims

1. A method for implanting a medical device, comprising:

forming at least one cut in a portion of a vertebra of a patient'"'"'s spine to separate the vertebra into at least two halves; and

positioning an elongate body between two halves of the vertebra to enlarge a spinal canal formed within the vertebra, the elongate body including at least one perforation formed therein, and a perforation-free anterior side that is positioned adjacent to the spinal canal.

2. The method of claim 1, wherein a first cut is formed in a spinous process of a vertebra of a patient'"'"'s spine to separate the spinous process into two halves that seat the elongate body therebetween, and wherein at least one of a second and third cut is formed on a side of the spinous process between the spinous articular process and the transverse process to form a hinge that is effective to allow the two halves of the spinous process to be separated.

3. The method of claim 2, wherein the elongate body is hollow, and opposed first and second open ends of the hollow elongate body are positioned adjacent to the two halves of the spinous process.

4. The method of claim 3, wherein the first and second open ends are angled such that planes defined by the first and second ends converge.

5. The method of claim 3, wherein the hollow elongate body has an anatomical cross-section extending in a direction transverse to a longitudinal axis extending between the opposed first and second open ends, such that the cross-section of the hollow elongate body conforms to the shape of the two halves of the spinous process.

6. The method of claim 5, wherein the cross-section of the hollow elongate body has a shape selected from the group consisting of a parallelogram, a square, a rectangle, a diamond, an oval, and a circle.

7. The method of claim 1, wherein the elongate body includes a longitudinal axis, opposed cephalad and caudal sides, and opposed posterior and anterior sides adjacent to the cephalad and caudal sides, the cephalad and caudal sides and the posterior and anterior sides defining an inner lumen having opposed first and second open ends.

8. The method of claim 7, wherein the posterior and anterior sides have a length extending along the longitudinal axis that is greater than a length of the cephalad and caudal sides.

9. The method of claim 7, wherein the a plurality of perforations are formed in at least one of the cephalad side, the caudal side, and the posterior side.

10. The method of claim 9, wherein the plurality of perforations comprise a plurality of elongated slots formed therein, each slot extending in a direction transverse to the longitudinal axis of the elongate body.

11. The method of claim 10, wherein at least one of the slots includes a suture-receiving recess formed therein that is effective to receive and prevent movement of a suture disposed within the slot, and wherein the method further comprises the step of passing at least one suture through at least one of the slots such that the at least one suture is positioned within at least one suture-receiving recess, and attached the suture to bone adjacent to the hollow elongate member to anchor the hollow elongate member to the patient'"'"'s vertebra.

12. The method of claim 1, wherein the anterior side of the elongate body is curved such that an outer surface of the anterior side is concave.

13. The method of claim 1, wherein the elongate body is curved such that an outer surface of the anterior side is concave, and an outer surface of an opposed posterior side is convex.

14. The method of claim 1, wherein the elongate body includes first and second halves positioned on opposed sides of a midpoint of the hollow elongate body, the first and second halves being angled with respect to one another.

15. A method for implanting a medical device, comprising:

cutting a spinous process in a patient'"'"'s vertebra to form a bisected spinous process having two halves;

separating the two halves of the bisected spinous process; and

positioning an elongate body between the two halves of the bisected spinous process to enlarge a spinal canal formed within the vertebra, the elongate body including a spinous process replacement member extending outward therefrom and adapted to replace the bisected spinous process.

16. The method of claim 15, wherein the spinous process replacement member has a shape that conforms to a natural shape of the spinous process.

17. The method of claim 15, further comprising the step of attaching muscle separated from the spinous process to the spinous process replacement member.

18. A method for implanting a medical device, comprising:

cutting a lamina in a patient'"'"'s vertebra such that a spinous process and a spinous articular process of the vertebra are separated from one another; and

positioning an elongate body between the separated spinous process and spinous articular process such that a fixation element receiving member extending outward from a first end of the elongate body is positioned adjacent to the a posterior side of the spinous articular process, and an extension member formed on the elongate body and opposed to the fixation element receiving member is positioned adjacent to an anterior side of the spinous articular process.

19. The method of claim 18, further comprising the step of attaching the fixation element receiving member to the spinous articular process using a fixation element.

20. The method of claim 19, wherein the fixation element receiving member includes a bore formed therein, and wherein the fixation element comprises a bone screw, and wherein the step of attaching the fixation element receiving member to the spinous articular process comprises threading the bone screw through the bore and into the spinous articular process.

21. The method of claim 18, wherein the fixation element receiving member and the extension member each extend at an angle away from one another with respect to a longitudinal axis of the elongate body that extends between opposed first and second ends of the elongate body.

22. The method of claim 21, wherein the fixation element receiving member extends in a posterior direction at an angle, relative to the longitudinal axis, in the range of about 35°

to 75°

.

23. The method of claim 18, wherein a first concave recess is formed in the first end of the elongate body between the fixation element receiving member and the extension member, and the first recess seats a portion of the spinous articular process.

24. The method of claim 23, further comprising a second concave recess formed in a second, opposed end of the elongate body, the second concave recess seating a portion of the cut lamina adjacent to the spinous process.

25. A method for implanting a medical device, comprising:

forming at least one cut in a portion of a vertebra of a patient'"'"'s spine to separate the vertebra into at least two halves;

positioning an elongate body between two halves of the vertebra, the elongate body including first and second opposed ends, each having a recess formed therein that is adapted to seat a bone structure to secure the implant between the two halves of the vertebra.