Spinal bone implant

• US 6,562,073 B2
• Filed: 02/06/2001
• Issued: 05/13/2003
• Est. Priority Date: 02/06/2001
• Status: Expired due to Term

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Inventors: Foley, Kevin T.
• Primary Examiner(s): Willse, David H.
• Assistant Examiner(s): GHERBI, SUZETTE JAIME J
• Application Number:
  US09/777,702
• Publication Number:
  US 20020107571A1
• Time in Patent Office: 826 Days
• Field of Search: 623/17.11, 623/17.16
• US Class Current: 623/17.11
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• 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 2002/30774 internally-threaded
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2310/00359 Bone or bony tissue

Abstract

Implantable devices useful for creating bony fusion particularly in intervetebral spinal fusion. The device is formed of bone and has a body portion with an upper flange member and an opposite lower flange member extending from the body portion. The upper and lower flange members are at least partially demineralized to create a flexible ligament extending from the body portion. In one application, the body portion is inserted into a disc space and the flexible ligament is secured to vertebrae on either side of the disc space. Techniques are also disclosed for making the implantable devices and for inserting the implantable device into an intervertebral disc space to promote interbody fusion.

Claims

1. An implant, comprising:

a body portion positionable in the disc space between adjacent upper and lower vertebrae;

an upper member extending from said body portion and configured to extend along the body of said upper vertebra; and

a lower member extending from said body portion and configured to extend along the body of said lower vertebra, wherein said body portion, said upper member, and said lower member are each made from bone material.

2. The implant of claim 1, wherein said upper member and said lower member are each flexible permitting movement of said upper member and said lower members in relation to said body portion.

3. The implant of claim 2, wherein said upper and lower members are made from at least partially demineralized bone.

4. The implant of claim 2, wherein said upper and lower members are made from completely demineralized bone.

5. The implant of claim 1, wherein said body portion includes an upper bearing surface and a lower bearing surface separated by a height, said height adapted to maintain spacing between the adjacent vertebrae.

6. The implant of claim 5, wherein each of said upper and lower bearing surfaces includes a bone engaging surface to inhibit expulsion of the implant from the disc space.

7. The implant of claim 1, wherein said body portion is a spinal fusion device and said body portion is adapted to maintain a desired spacing between the adjacent vertebrae.

8. The implant of claim 7, wherein said upper member and said lower member each have an opening formed therethrough to receive a fastener to secure the upper and lower member to the bodies of the upper and lower vertebrae, respectively.

9. The implant of claim 1, wherein said body portion, said upper member, and said lower member are formed of a single bone segment.

10. The implant of claim 1, wherein said body portion has a cavity allowing bone growth between the upper and lower vertebrae.

11. An implant, comprising:

a bone body extending between a first bearing surface and a second bearing surface; and

an upper bone member extending from said body in a first direction and a lower bone member extending from said body in a second direction opposite said first direction, wherein said upper and lower bone members are at least partially demineralized and are configured to extend along an upper vertebral body and a lower vertebral body, respectively, when said bone body is positioned in a space between the upper vertebral body and the lower vertebral body.

12. The implant of claim 11, wherein said body is a ring shaped bone segment.

13. The implant of claim 11, wherein:

said first bearing surface is adapted to contact an endplate of an upper vertebral body and said second bearing surface is adapted to contact an endplate of an adjacent lower vertebral body; and

said upper bone member extends alongside said upper vertebral body and said lower bone member extends alongside said lower vertebral body.

14. The implant of claim 13, wherein said upper bone member and said lower bone member each have an opening formed therethrough to receive a fastener to secure the implant to the upper and lower vertebral bodies, respectively.

15. The implant of claim 11, wherein:

said bone body is positionable in the disc space between an upper vertebral body and a lower vertebral body; and

said upper and lower members act as a ligament extending between and connecting the upper vertebral body and the lower vertebral body.

16. The implant of claim 11, wherein said implant is formed of a single segment of bone.

17. A spinal fusion implant adapted for insertion into the space between adjacent first and second vertebral bodies, comprising:

a bone body having a first bearing surface for contacting an endplate of the first vertebral body and a second bearing surface for contacting an endplate of the second vertebral body; and

at least one flexible portion extending from the bone body for securement to the first and second vertebral bodies outside the disc space.

18. The spinal fusion implant of claim 17, wherein said at least one flexible portion includes a pair of flexible portions.

19. The spinal fusion implant of claim 18, wherein said flexible portions act as a ligament between said first and second vertebral bodies.

20. The spinal fusion implant of claim 18, wherein the implant has a leading end and an opposite trailing end, and said flexible portions are positioned adjacent said trailing end.

21. The implant of claim 17, wherein said implant is formed from a single segment of bone.

22. A method of preparing a bone implant, comprising:

providing a rigid bone segment having a body portion with an upper bearing surface and an opposite lower bearing surface, said rigid bone segment further including an upper flange member and an opposite lower flange member each extending from said body portion; and

at least partially demineralizing the upper and lower flange members to create a flexible upper flange member and a flexible lower flange member extending from the rigid body portion, wherein said upper and lower flange members are configured to extend along an upper vertebral body and a lower vertebral body, respectively, when said body portion is positioned in a space between the upper vertebral body and the lower vertebral body.

23. The method of claim 22, wherein said at least partially demineralizing includes exposing said rigid upper flange member and said rigid lower flange member to a demineralizing fluid.

24. The method of claim 22, further including limiting contact of the body portion with the demineralizing fluid.

25. The method of claim 24, wherein said limiting utilizes hydrostatic pressure to limit the movement of the demineralizing fluid into the body portion.

26. The method of claim 22, further including forming a bone engaging surface on the upper and lower bearing surfaces of the implant.

27. The method of claim 26, wherein said bone engaging surface is configured to prevent movement of the implant.

28. The method of claim 22, wherein the implant is formed from a single segment of bone.

32. The method of claim 24, wherein the upper and lower bearing surfaces extend substantially parallel to one another.

33. The method of claim 24, further including forming a bone engaging surface on the upper and lower bearing surfaces of the body portion.

29. A method of preparing a bone implant, comprising:

obtaining a rigid bone segment; and

forming from said rigid bone segment an implant having a body portion with an upper bearing surface and opposite lower bearing surface, said rigid bone segment further including an upper flange member and an opposite lower flange member each extending from said body portion, wherein said upper and lower flange members are configured to extend along an upper vertebral body and a lower vertebral body, respectively, when said body portion is positioned in a space between the upper vertebral body and the lower vertebral body.

30. The method of claim 29, further comprising at least partially demineralizing the upper and lower flange members to create a flexible upper flange member and a flexible lower flange member extending from the body portion.

31. The method of claim 29, wherein:

the upper and lower bearing surfaces each extend between a leading end and a trailing end of the body portion; and

the upper and lower flange members each extend from the body portion at the trailing end.

34. The method of claim 29, wherein the implant is formed from a single segment of bone.