Intervertebral prosthetic disc with metallic core

• US 7,575,599 B2
• Filed: 07/30/2004
• Issued: 08/18/2009
• Est. Priority Date: 07/30/2004
• Status: Active Grant

• Current Assignee: Simplify Medical Pty. Ltd. (Nuvasive Incorporated)
• Original Assignee: SpinalMotion, Inc. (Globus Medical, Inc.)
• Inventors: Villiers, Malan de, Hovda, David, Hahnle, Ulrich
• Primary Examiner(s): Philogene; Pedro
• Application Number:
  US10/903,913
• Publication Number:
  US 20060025862A1
• Time in Patent Office: 1,845 Days
• Field of Search: 623 1711- 1716, 623/18.11, 606/61
• US Class Current: 623/17.14
• 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 2/4425 made of articulated components
• CPC Class Codes: A61F 2002/30077 shrinkable
• 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 2002/30365 with additional means for limiting said rotation
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30485 plastically deformable
• CPC Class Codes: A61F 2002/30649 Ball-and-socket joints
• CPC Class Codes: A61F 2002/30662 with rotation-limiting means
• CPC Class Codes: A61F 2002/30673 Lubricating means, e.g. synovial pocket
• CPC Class Codes: A61F 2002/30878 with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• CPC Class Codes: A61F 2002/30884 Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30899 Protrusions pierced with apertures
• CPC Class Codes: A61F 2002/30904 serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/443 having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2210/0066 shrinkable
• 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 2310/00017 Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00395 : Coating or prosthesis-covering structure made of metals or of alloys
• CPC Class Codes: A61F 2310/00407 : Coating made of titanium or of Ti-based alloys
• CPC Class Codes: A61F 2310/0088 : Coating made of titanium nitride
• CPC Class Codes: Y10T 29/49826 : Assembling or joining

Abstract

A prosthetic disc for insertion between adjacent vertebrae includes a core having upper and lower curved surfaces and upper and lower plates. At least one of the curved surfaces of the core is metallic, and in some embodiments the entire core is metallic. Each plate has an outer surface which engages a vertebra and a metallic inner curved surface which is shaped to slide over one of the curved surfaces of the core. In some embodiments, the center of rotation of the core is free to move relative to the upper and lower metallic plates. In some embodiments, one or more channels extend across one or both of the curved surfaces of the core for allowing passage of bodily fluid to promote lubrication between the core and at least one of the plates.

Claims

1. A prosthetic disc for insertion between adjacent vertebrae, the prosthetic disc comprising:

a core having upper and lower curved surfaces, wherein each of the curved surfaces comprises a metal;

upper and lower plates, each plate having an outer surface which engages a vertebra and a metallic inner curved surface which is shaped to slide and translate over one of the curved metallic surfaces of the core, wherein a center of rotation of the core is free to move relative to the upper and lower plates;

a peripheral restraining structure on at least one of the upper plate and the lower plate to hold the core against a curved surface of at least one of the plates during sliding movement of the plates over the core, the peripheral restraining structure comprising an annular structure extending over at least a portion of the periphery of the core and a ring structure on one of the upper and lower plates, which ring structure engages and retains the annular structure,

wherein the restraining structure is adapted to contact an opposing plate to limit relative inclination of the plates during sliding movement of the plates over the core.

2. A prosthetic disc as in claim 1, wherein the plates comprise at least one metal selected from the group consisting of cobalt chrome molybdenum, titanium and stainless steel.

3. A prosthetic disc as in claim 2, wherein each plate comprises an MRI compatible material coupled with a hardened material forming the inner surface.

4. A prosthetic disc as in claim 3, wherein the MRI-compatible material comprises titanium and the hardened material comprises cobalt chrome molybdenum.

5. A prosthetic disc as in claim 3, wherein the MRJ-compatible material comprises titanium and the hardened material comprises titanium nitride.

6. A prosthetic disc as in claim 3, wherein the MM-compatible material and the hardened material are coupled together using a process selected from the group consisting of welding, lamination, slip fitting, interference fitting, adhesion and heating and cooling one material to attach it to another.

7. A prosthetic disc as in claim 1, wherein at least one curved surface of the core comprises at least one metal selected from the group consisting of cobalt chrome molybdenum, titanium and stainless steel.

8. A prosthetic disc as in claim 7, wherein the entire core is metallic.

9. A prosthetic disc as in claim 8, wherein the core and both plates comprise the same metal.

10. A prosthetic disc as in claim 7, wherein a portion of the core between the curved surfaces comprises ceramic.

11. A prosthetic disc as in claim 7, wherein a portion of the core between the curved surfaces comprises a polymer.

12. A prosthetic disc as in claim 1, wherein the core comprises two oppositely facing convex low-friction surfaces which slidably engage the inner curved surfaces of the upper and lower plates.

13. A prosthetic disc as in claim 1, wherein at least one of the curved surfaces is spherical.

14. A prosthetic disc as in claim 13, wherein both curved surfaces are spherical.

15. A prosthetic disc as in claim 1, further including at least one surface channel on at least one of the upper and lower curved surfaces of the core for allowing passage of bodily fluid to promote lubrication between the core and at least one of the plates.

16. A prosthetic disc as in claim 15, wherein the at least one surface channel comprises a helical channel.

17. A prosthetic disc as in claim 15, wherein the at least one surface channel comprises two perpendicular channels.

18. A prosthetic disc as in claim 15, wherein each of the upper and lower surfaces of the core includes at least one surface channel.

19. A prosthetic disc as in claim 1 or 15, further including at least one surface channel on at least one of the inner curved surfaces of the plates.

20. A prosthetic disc as in claim 19, wherein each of the inner curved surfaces of the plates includes at least one surface channel.

21. A prosthetic disc as in claim 1, wherein at least one of the upper and lower curved surfaces of the core includes threads for movably coupling the core with at least one of the upper and lower plates via complementary threads thereon.

22. A prosthetic disc as in claim 1, wherein movement of the core within the restraining structure is unconstrained.

23. A prosthetic disc as in claim 1, wherein the peripheral restraining structure defines a stop structure to limit relative inclination of the plates during sliding movement of the plates over the core.

24. A prosthetic disc as in claim 1, wherein the peripheral restraining structure defines a stop structure to limit axial rotation of the plates during sliding movement of the plates over the core.

25. A prosthetic disc as in claim 1, wherein the peripheral restraining structure will engage one side of the core to lift an opposite side of the core during sliding movement of the plates over the core.

26. A prosthetic disc as in claim 1, wherein the ring structure comprises a flange which defines an overhang, and wherein at least part of the annular structure on the core extends into the overhang to provide an interference fit of the core with the flange.

27. A prosthetic disc as in claim 26, wherein the annular structure comprises a rim which extends continuously around a lateral circumference of the core, the rim having a greater width at least some locations than a width of an inner edge of the flange to provide said interference fit.

28. A prosthetic disc as in claim 1, wherein the outer surfaces of the upper and lower plates have at least one surface feature for promoting attachment of the outer surfaces to the vertebrae.

29. A prosthetic disc as in claim 28, wherein the at least one surface feature comprises a plurality of serrations disposed along the outer surfaces.

30. A prosthetic disc as in claim 29, wherein the at least one surface feature further comprises a surface coating.

31. A prosthetic disc as in claim 30, wherein the surface coating comprises plasma sprayed titanium.

32. A prosthetic disc as in claim 29, wherein the at least one surface feature further comprises a plurality of concavities formed by aluminum oxide blasting.

33. A prosthetic disc as in claim 29, wherein the at least one surface feature further comprises at least one fin disposed on each of the outer surfaces.

34. A prosthetic disc as in claim 1, wherein the core has a height between the upper and lower curved surfaces and a width, and wherein a core maximum height is smaller than the core width.

35. A prosthetic disc for insertion between adjacent vertebrae, the prosthetic disc comprising:

a core having upper and lower curved surfaces, wherein each of the curved surfaces comprises a metal;

upper and lower plates, each plate having an outer surface which engages a vertebra and a metallic inner curved surface which is shaped to slide and translate over one of the curved metallic surfaces of the core, wherein a center of rotation of the core is free to move relative to the upper and lower plates; and

a peripheral restraining structure on at least one of the upper plate and the lower plate to hold the core against a curved surface of at least one of the plates during sliding movement of the plates over the core, wherein the restraining structure is adapted to contact an opposing plate to limit relative inclination of the plates during sliding movement of the plates over the core;

wherein the peripheral restraining structure comprises;

an annular structure extending over at least a portion of the periphery of the core, and

a ring structure on one of the upper and lower plates,

wherein the annular structure has a diameter sized to pass through the ring structure, and wherein the core is retained within the ring structure due to forces placed on the prosthetic disc via the adjacent vertebrae.

36. A prosthetic disc for insertion between adjacent vertebrae, the prosthetic disc comprising:

a core having upper and lower curved surfaces, wherein each of the curved surfaces comprises a metal;

upper and lower plates, each plate having an outer surface which engages a vertebra and a metallic inner curved surface which is shaped to slide and translate over one of the curved metallic surfaces of the core, wherein a center of rotation of the core is free to move relative to the upper and lower plates; and

a peripheral restraining structure on at least one of the upper plate and the lower plate to hold the core against a curved surface of at least one of the plates during sliding movement of the plates over the core, wherein the restraining structure is adapted to contact an opposing plate to limit relative inclination of the plates during sliding movement of the plates over the core;

wherein the peripheral restraining structure comprises;

a groove around a lateral edge of the core; and

a ring structure on at least one of the upper and lower plates, said ring structure having a lip which engages the groove.

37. A prosthetic disc as in claim 36, wherein the lip extends into the groove to form an interference fit between the ring structure and the core.

38. A prosthetic disc for insertion between adjacent vertebrae, the prosthetic disc comprising:

a metallic core having upper and lower curved metallic spherical surfaces;

first and second metallic plates, each plate having an outer surface which engages a vertebra and an inner curved spherical surface which slides and translates over the curved spherical surface of the core, wherein a center of rotation of the core is free to move relative to the upper and lower metallic plates; and

a peripheral restraining structure on at least one of the first and second plates to hold the core against a curved surface of at least one of the plates during sliding movement of the plates over the core, the peripheral restraining structure comprising a peripheral structure extending over at least a portion of the periphery of the core and a projecting structure on one of the first and second plates, which projecting structure engages and retains the peripheral structure,

wherein the restraining structure is adapted to contact an opposing plate to limit relative inclination of the plates during sliding movement of the plates over the core.

39. A prosthetic disc as in claim 38, further including at least one surface channel on each of the upper and lower curved surfaces of the core for promoting flow of lubricating fluid between the core and the plates.

40. A prosthetic disc as in claim 39, further including at least one surface channel on each of the inner curved surfaces of the first and second plates for promoting flow of lubricating fluid between the core and the plates.

41. A prosthetic disc as in claim 38, wherein the core and the plates comprise at least one metal selected from the group consisting of cobalt chrome molybdenum, titanium and stainless steel.

42. A prosthetic disc as in claim 41, wherein the core and the plates comprise the same metal.

43. A prosthetic disc as in claim 38, wherein the core has a height between the upper and lower curved surfaces and a width, and wherein a core maximum height is smaller than the core width.

44. A prosthetic disc as in claim 38, wherein the projecting structure comprises an inwardly projecting ring.

45. A method for implanting an intervertebral disc prosthesis between adjacent vertebrae, the method comprising:

implanting an upper metallic plate against a lower surface of an upper vertebral body;

implanting a lower metallic plate against an upper surface of a lower vertebral body;

disposing a core between the upper and lower plates, the core having curved surface comprising a metal, wherein disposing the core between the plates comprises passing an annular structure on the core through a ring structure on at least one of the plates, and wherein the annular structure has a diameter sized to pass through the ring structure to restrain peripheral movement of the core; and

allowing the core to float with a mobile center of rotation between spherical cavities in each of the upper and lower plates.

46. A method as in claim 45, wherein implanting each of the plates comprises sliding a fin on each plate into a corresponding groove formed in its respective vertebral body.

47. A method as in claim 46, wherein sliding the fin is performed in a direction from posterior to anterior.

48. A method as in claim 46, wherein sliding the fin is performed in a lateral direction.

49. A method as in claim 46, wherein sliding the fin is performed in angled direction between posterior-anterior and lateral.

50. A method as in claim 46, wherein implanting further comprises contacting textured outer surfaces of the upper and lower plates with the upper and lower surfaces of the vertebral bodies.

51. A method as in claim 45, wherein the core has a height between the upper and lower curved surfaces and a width, and wherein a core maximum height is smaller than the core width.

52. A prosthetic disc for insertion between adjacent vertebrae, the prosthetic disc comprising:

a core having upper and lower bearing surfaces, wherein each of the bearing surfaces comprises a metal;

upper and lower plates, each plate having an outer surface which engages a vertebra and a metallic inner bearing surface which is shaped to slide and translate over one of the bearing metallic surfaces of the core, wherein a center of rotation of the core is free to move relative to the upper and lower plates;

a peripheral restraining structure on at least one of the upper plate and the lower plate to hold the core against a bearing surface of at least one of the plates during sliding movement of the plates over the core, the peripheral restraining structure comprising an annular structure extending over at least a portion of the periphery of the core and a ring structure on one of the upper and lower plates, which ring structure engages and retains the annular structure,

wherein the restraining structure is adapted to contact an opposing plate to limit relative inclination of the plates during sliding movement of the plates over the core.

53. A prosthetic disc as in claim 52, wherein at least one bearing surface of the core comprises at least one metal selected from the group consisting of cobalt chrome molybdenum, titanium and stainless steel.

54. A prosthetic disc as in claim 53, wherein the entire core is metallic.

55. A prosthetic disc as in claim 54, wherein the core and both plates comprise the same metal.

56. A prosthetic disc as in claim 52, wherein the core comprises two oppositely facing convex low-friction surfaces which slidably engage the inner bearing surfaces of the upper and lower plates.

57. A prosthetic disc as in claim 52, wherein at least one of the bearing surfaces of the core is spherical.

58. A prosthetic disc as in claim 52, wherein both bearing surfaces of the core are spherical.

59. A prosthetic disc as in claim 52, wherein at least one of the upper and lower bearing surfaces of the core includes threads for movably coupling the core with at least one of the upper and lower plates via complementary threads thereon.

60. A prosthetic disc as in claim 52, wherein movement of the core within the restraining structure is unconstrained.

61. A prosthetic disc as in claim 52, wherein the peripheral restraining structure defines a stop structure to limit axial rotation of the plates during sliding movement of the plates over the core.

62. A prosthetic disc as in claim 52, wherein the peripheral restraining structure will engage one side of the core to lift an opposite side of the core during sliding movement of the plates over the core.

63. A prosthetic disc as in claim 52, wherein the ring structure comprises a flange which defines an overhang, and wherein at least part of the annular structure on the core extends into the overhang to provide an interference fit of the core with the flange.

64. A prosthetic disc as in claim 63, wherein the annular structure comprises a rim which extends continuously around a lateral circumference of the core, the rim having a greater width at least some locations than a width of an inner edge of the flange to provide said interference fit.