Modular disc prosthesis

• US 20030187506A1
• Filed: 03/27/2002
• Published: 10/02/2003
• Est. Priority Date: 03/27/2002
• Status: Active Grant

• Current Assignee: Depuy Acromed Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Acromed Incorporated (Johnson & Johnson)
• Inventors: Ross, Raymond, Boomer, Mark, OʼNeil, Michael
• Granted Patent: US 6,726,720 B2
• Time in Patent Office: Days
• US Class Current: 623/17.13
• 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 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• CPC Class Codes: A61F 2002/30331 made by longitudinally pushing a protrusion into a complementarily-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30451 soldered or brazed or welded
• CPC Class Codes: A61F 2002/30492 using a locking pin
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30845 with cutting edges
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2220/0041 using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2220/005 using adhesives
• CPC Class Codes: A61F 2220/0058 soldered or brazed or welded
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

A modular implant that is effective to replace a damaged or degenerated spinal disc is provided. The implant includes a central core member having superior and inferior surfaces, a superior endplate member having a bone-contacting surface and a mating surface effective to mate with the superior surface of the central core member, and an inferior endplate member having a bone-contacting surface and a mating surface effective to mate with the inferior surface of the central core member. The modularity of the implant allows the surgeon to select and properly fit each modular endplate member separately during the surgical procedure, thereby eliminating the need to prepare the endplates of each adjacent vertebrae, and/or the bone-contacting surfaces of the implant.

Claims

1. A modular implant, comprising:

a central core member having superior and inferior surfaces;

a superior endplate member having a bone-contacting surface and a mating surface effective to fixedly engage the superior surface of the central core member;

an inferior endplate member having a bone-contacting surface and a mating surface effective to fixedly engage the inferior surface of the central core member.

2. The modular implant of claim 1, wherein the superior surface of the central core member includes a superior attachment member adapted to mate with the superior endplate member, and the inferior surface of the central core member includes an inferior attachment member adapted to mate with the inferior endplate member.

3. The modular implant of claim 2, wherein the attachment members are adhesively mated to the central core member.

4. The modular implant of claim 2, wherein the superior attachment member is slidably matable with the superior endplate member, and the inferior attachment member is slidably matable with the inferior endplate member.

5. The modular implant of claim 4, further comprising a connecting element disposed on the superior and inferior attachment members and the superior and inferior endplate members for slidably mating the superior and inferior attachment members to the superior and inferior endplate members.

6. The modular implant of claim 5, wherein the connecting element comprises a first complementary member formed on each of the superior and inferior attachment members, and a second complementary member formed on each of the endplate members, the first complementary member being slidably matable with the second complementary member.

7. The modular implant of claim 5, wherein the connecting element comprises a female dovetail formed on one of the attachment members and the endplate members, and a complementary male dovetail formed on the other one of the attachment members and the endplate members.

8. The modular implant of claim 5, wherein the connecting element comprises at least one protruding element formed on one of the attachment members and the endplate members, and at least one bore formed on the other one of the attachment members and the endplate members, the bore being adapted to receive the protruding element.

9. The modular implant of claim 2, wherein the bone-contacting surfaces of the superior and inferior endplate members each have a shape adapted to conform to the endplates of adjacent vertebral bodies.

10. The modular implant of claim 9, wherein the shape of the bone-contacting surfaces of the superior and inferior endplate members is selected from the group consisting of a convex shape, a domed shape, a serpentine shape, a ramped shape, and an angled shape, and combinations thereof.

11. The modular implant of claim 5, further comprising a locking mechanism formed on at least one of the attachment members and the endplate members, the locking mechanism being effective to fixedly engage the superior attachment member to the superior endplate member and the inferior attachment member to the inferior endplate member.

12. The modular implant of claim 11, wherein the locking mechanism comprises complementary male and female dovetail components for providing locking engagement of the attachment members to the endplate members.

13. The modular implant of claim 12, further comprising a bore extending through the complementary male and female dovetail components, and a pin slidably disposed through the bore, the pin being effective to prevent movement of the attachment members with respect to the endplate members.

14. The modular implant of claim 11, wherein the locking mechanism comprises a bore extending through the attachment member and the endplate member, and a pin member adapted to be disposed through the bore.

15. The modular implant of claim 2, wherein the implant includes a posterior portion and an anterior portion, and the superior and inferior endplate members are slidably matable with the superior and inferior attachment members in the posterior and anterior directions.

16. The modular implant of claim 2, wherein the implant includes a posterior portion and an anterior portion, and the superior and inferior endplate members are slidably matable with the superior and inferior attachment members in a posterio-lateral direction.

17. The modular implant of claim 2, wherein the implant includes a posterior portion and an anterior portion, and the superior and inferior endplate members are slidably matable with the superior and inferior attachment members in an anterio-lateral direction.

18. The modular implant of claim 2, wherein the central core member is made from a polymeric material.

19. A modular implant, comprising:

a disc member having

a central core member having superior and inferior surfaces;

a superior attachment plate disposed on the superior surface of the central core member; and

an inferior attachment plate disposed on the inferior surface of the central core member;

a superior endplate member having a bone-contacting surface and an engagement surface effective to mate with the superior attachment plate of the disc member; and

an inferior endplate member having a bone-contacting surface and an engagement surface effective to mate with the inferior attachment plate of the disc member.

20. The modular implant of claim 19, wherein the superior and inferior endplate members are slidably matable with the superior and inferior attachment plates of the disc member.

21. The modular implant of claim 20, wherein the disc member includes a posterior portion and an anterior portion, and the superior and inferior endplate members are slidably matable with the superior and inferior attachment plates in the posterior and anterior directions.

22. The modular implant of claim 21, further comprising a first locking mechanism disposed between the superior endplate member and the superior attachment plate, and a second locking mechanism disposed between the inferior endplate member and the inferior attachment plate, the locking mechanisms being effective to lock the endplate members to the disc member.

23. The modular implant of claim 22, wherein the locking mechanism comprises a complementary male and female dovetail members adapted to provide frictional engagement of the endplate members to the disc member.

24. The modular implant of claim 19, wherein the one of the attachment plates and endplate members include a plurality of protruding members, and the other one of the attachment plates and endplate members include a plurality of bores adapted to receive the protruding members.

25. The modular implant of claim 19, wherein at least a portion of the bone-contacting surface of at least one of the endplate members include a plurality of bone-engaging surface features.

26. The modular implant of claim 19, wherein the bone-contacting surfaces of the superior and inferior endplate members each have a shape selected from the group consisting of a convex shape, a domed shape, a serpentine shape, a ramped shape, and an angled shape, and combinations thereof.

27. The modular implant of claim 19, wherein the disc member is made from a polymeric material.

28. A modular implant system, comprising:

a central core member having superior and inferior engagement surfaces;

a plurality of superior endplate members removably matable with the superior surface of the central core member; and

a plurality of inferior endplate members removably matable with the inferior surface of the central core member.

29. The modular implant system of claim 28, wherein the superior and inferior endplate members are slidably matable with the central core member.

30. The modular implant system of claim 28, wherein the superior and inferior endplate members each have an engagement surface matable with the central core member and a bone contacting surface, each bone contacting surface of each endplate member having a shape adapted to mate with a vertebral endplate.

31. The modular implant system of claim 30, wherein the shape of the bone contacting surface of each endplate member is selected from the group consisting of a convex shape, a concave shape, a domed shape, an angled shape, and a serpentine shape.

32. The modular implant system of claim 29, further comprising a superior engagement plate fixedly disposed on the superior surface of the central core member and matable with one of the plurality of superior endplate members, and an inferior engagement plate fixedly disposed on the inferior surface of the central core member and matable with one of the plurality of inferior endplate members.

33. The modular implant system of claim 32, wherein the central core member is made from a polymeric material and is compression molded to mate to the superior and inferior engagement plates.

34. The modular implant system of claim 32, wherein the superior and inferior engagement plates each include one of a female and male dovetail, and the plurality of superior and inferior endplate members each include the other of a female and male dovetail.

35. The modular implant system of claim 34, wherein the male and female dovetails are adapted to provide a locking frictional engagement between the engagement plates and the endplates.

36. The modular implant system of claim 34, wherein the central core member includes a posterior side, an anterior side, and first and second lateral sides, the male and female dovetails of the engagement plates and the endplate members extending in a posterior-anterior direction.

37. The modular implant system of claim 34, wherein the central core member includes a posterior side, an anterior side, and first and second lateral sides, the male and female dovetails of the engagement plates and the endplate members extending in an anterio-lateral direction.

38. The modular implant system of claim 34, wherein the central core member includes a posterior side, an anterior side, and first and second lateral sides, the male and female dovetails of the engagement plates and the endplate members extending in a posterio-lateral direction.

39. A method for inserting an implant between a superior vertebrae and an inferior vertebrae, each vertebrae having an endplate, the method comprising:

providing an implant having

a central core member having superior and inferior surfaces,

a superior endplate member removably matable with the superior surface of the central core member and having a bone-contacting surface, and

an inferior endplate member removably matable with the inferior surface of the central core member and having a bone-contacting surface;

separating adjacent bone structures;

positioning the superior and inferior endplate members adjacent the endplates of the superior and inferior vertebrae;

slidably inserting the central core member between the superior and inferior endplate members.