Artificial intervertebral disc device

• US 20030220691A1
• Filed: 10/29/2002
• Published: 11/27/2003
• Est. Priority Date: 05/23/2002
• Status: Active Grant

• Current Assignee: Pioneer Surgical Technology Incorporated (Surgalign Holdings, Inc.)
• Original Assignee: Pioneer Laboratories Incorporated
• Inventors: Songer, Matthew N., Gephart, Matthew P., Kilpela, Thomas S., Janowski, Brian P., Berrevoets, Gregory A.
• Granted Patent: US 7,001,433 B2
• Time in Patent Office: Days
• US Class Current: 623/17.14
• CPC Class Codes: A61F 2/30742 Bellows or hose-like seals; Sealing membranes A61B17/8808 takes precedence; sealing membranes for retaining bone substitute A61F2/2846
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• 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 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/30016 differing in hardness, e.g. Vickers, Shore, Brinell
• CPC Class Codes: A61F 2002/30123 with two diametrically opposed lobes
• CPC Class Codes: A61F 2002/302 toroidal, e.g. rings
• CPC Class Codes: A61F 2002/30242 spherical
• CPC Class Codes: A61F 2002/30245 Partial spheres
• CPC Class Codes: A61F 2002/30299 umbrella-shaped or mushroom-shaped
• 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 2002/3039 with possibility of relative movement of the rib within the groove
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30528 Means for limiting said movement
• CPC Class Codes: A61F 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30581 having a pocket filled with fluid, e.g. liquid
• CPC Class Codes: A61F 2002/30649 Ball-and-socket joints
• CPC Class Codes: A61F 2002/30673 Lubricating means, e.g. synovial pocket
• CPC Class Codes: A61F 2002/30685 Means for reducing or preventing the generation of wear particulates
• CPC Class Codes: A61F 2002/30738 : Sleeves
• CPC Class Codes: A61F 2002/30784 : Plurality of holes
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30919 : Sleeves
• CPC Class Codes: A61F 2002/30934 : Special articulating surfaces
• CPC Class Codes: A61F 2002/30935 : Concave articulating surface composed of a central conforming area surrounded by a peripheral annular non-conforming area
• CPC Class Codes: A61F 2002/443 : having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2002/444 : for replacing the nucleus pulposus
• 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 2230/0006 : circular
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61F 2230/0071 : spherical
• CPC Class Codes: A61F 2230/0093 : Umbrella-shaped, e.g. mushroom-shaped
• CPC Class Codes: A61F 2250/0018 : differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0019 : differing in hardness, e.g. Vickers, Shore, Brinell
• 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 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00574 : Coating or prosthesis-covering structure made of carbon, e.g. of pyrocarbon
• CPC Class Codes: Y10S 606/907 : Composed of particular material or coated

Abstract

Artificial disc devices are disclosed that restore correct anatomical intervertebral spacing for damaged discs while maintaining a substantially normal range of biomechanical movement for the vertebrae between which they are implanted. The disc devices include center bearing and outer or annular bearing portions with the center bearing portion including generally axially extending locating surfaces which cooperate with the facing vertebral surfaces to resist migration. The outer bearing portion is for load bearing or load sharing with the center bearing portion and includes surfaces that extend radially toward the periphery of the vertebrae so that subsidence about the center bearing portion is minimized. Alternate forms of the disc devices include one with an axially enlarged center ball bearing having an annular ring bearing extending thereabout and another having upper and lower plate members with a central bumper member and a surrounding resilient annular member therebetween.

Claims

1. A spinal artificial disc device for being implanted between adjacent axially spaced upper and lower vertebrae, the artificial disc device comprising:

upper and lower central bearing surface portions having an arcuate, generally axially extending configuration for projecting toward and slidingly engaging against respective facing vertebral surfaces;

upper and lower outer bearing surface portions that generally extend radially outward from corresponding upper and lower central bearing surface portions for projecting along the vertebral surfaces,

the central bearing surface portions being axially spaced by a greater distance than the radially outer bearing surface portions with the central and outer bearing surface portions sharing compressive loads generated during spinal movements for minimizing vertebral subsidence about the axially enlarged central bearing surface portions; and

junctures between the upper and lower central bearing surface portions and the corresponding upper and lower outer bearing surface portions at which the bearing surface portions change directions from extending generally axially on the central bearing surface portions to extending generally radially on the outer bearing surface portions.

2. The artificial disc device of claim 1 including:

a central ball bearing having an outer spherical surface that includes the central arcuate bearing surface portions; and

an outer annular bearing having the outer bearing surface portions formed thereon and including an inner side surface facing the central bearing spherical surface and being configured to allow relative rotation between the central spherical bearing and the annular bearing.

3. The artificial disc device of claim 2 wherein the inner side surface has a flat configuration extending generally axially and radially spaced from the spherical surface or an arcuate configuration having a radius of curvature similar to that of the spherical surface.

4. The artificial disc device of claim 1 wherein the upper central and outer bearing surface portions are formed on an upper plate member and the lower central and outer bearing surface portions are formed on a lower plate member.

5. The artificial disc device of claim 4 including an annular member between the upper and lower plate members of a predetermined resilient material for providing a cushioned support therebetween, and a plug member about which the annular member extends having an axial thickness less than that of the annular member and being of a predetermined material that is harder than the resilient material of the annular member to limit overloading thereof.

6. The artificial disc device of claim 1 including:

a bearing body having a central enlarged arcuate bearing portion, and an outer bearing portion on which the outer bearing surface portions are formed; and

upper and lower dome shells configured to slide on the arcuate bearing portion and having the respective upper and lower central bearing surface portions thereon.

7. The artificial disc device of claim 6 wherein the enlarged arcuate bearing portion has a spherical configuration.

8. The artificial disc device of claim 1 wherein the central arcuate surface portions have a greater curvature than the outer bearing surface portions.

9. The artificial disc device of claim 8 wherein the outer bearing surface portions are curved, flat, or contoured.

10. The artificial disc device of claim 1 wherein the upper and lower outer bearing surface portions are formed on an outer bearing portion which has radially inner surfaces adjacent the central bearing surface portions configured to allow relative movement therebetween.

11. The artificial disc device of claim 10 wherein the outer bearing portion includes a body having an annular portion, and

a central bearing portion with the outer bearing annular body portion extending about the central bearing portion and central bearing surface portions.

12. The artificial disc device of claim 11 wherein the annular outer bearing portion and central bearing portions are distinct members.

13. The artificial disc device of claim 11 wherein the central bearing portion includes a central body portion integral with outer bearing annular body portion.

14. The artificial disc device of claim 13 wherein the central and annular body portions include a radially extending web wall that spaces said body portions by a predetermined gap spacing;

and

upper and lower shells of the central bearing portion which have the respective upper and lower arcuate central surface portions thereon with the shells and central body portion being configured to permit sliding of the shells on the central body portion.

15. The artificial disc device of claim 1 including an outer bearing portion extending about the central bearing surface portions and having a body with the outer bearing surface portions formed thereon, the body of the outer bearing portion being of a resilient material and the central bearing surface portions being of a material harder than the resilient material, and

a compression limiter in the body of the outer bearing portion that is of a material harder than that of the outer bearing portion body to resist deformation thereof under compressive loads.

16. The artificial disc device of claim 15 wherein the outer bearing portion includes an annular body portion, and the compression limiter comprises a ring embedded in the annular body portion.

17. The artificial disc device of claim 1 wherein the outer bearing surface portions each have a perimeter that generally defines one of a heart shape and an oval shape.

18. The artificial disc device of claim 1 including an outer bearing portion extending about the central bearing surface portions and having the outer bearing surface portions formed thereon, and

a cushioning material disposed axially intermediate the outer bearing surface portions.

19. The artificial disc device of claim 18 wherein the outer bearing portion comprises upper and lower annular plates having the respective upper and lower central bearing surface portions formed thereon, and the cushioning material extends between the plates to bias the plates apart and allow resilient shifting of the plates relative to each other during vertebral movements.

20. The artificial disc device of claim 1 including an arcuate central bearing portion and upper and lower shells on which the respective upper and lower central bearing surface portions are formed and which are slidingly supported on the central bearing portion.

21. The artificial disc device of claim 20 wherein the central bearing portion has an axial opening, and at least one of the shells includes a projection extending in the opening to limit axial shifting of the shells toward each other.

22. The artificial disc device of claim 20 wherein the arcuate central bearing portion includes a radially extending wall and upper and lower arcuate bearing rings supported for lateral sliding on the wall disposed therebetween with the shells supported for sliding over the bearing rings to allow for lateral movement of the shells during vertebral movements.

23. The artificial disc device of claim 1 including an outer bearing portion on which the outer bearing surface portions are formed and having a body of a material having a predetermined compressibility and a plurality of apertures in the body to vary the compressibility thereof from the predetermined compressibility.

24. The artificial disc device of claim 23 wherein the body has a predetermined number, arrangement and sizing of the apertures to provide for a controlled variation of the compressibility of the body.

25. The artificial disc device of claim 1 wherein the central bearing surface portions are formed on a central bearing and the outer bearing surface portions are formed on an outer bearing including an annular body that extends about the central bearing, the central bearing having a body that is axially enlarged relative to the annular body.

26. The artificial disc device of claim 25 wherein the central bearing body comprises a generally spherical ball body or an axially elongated post body.

27. The artificial disc device of claim 1 including a bearing body having an axially enlarged central bearing body portion and an outer annular body portion extending about the central body portion, and a web wall integrally interconnecting the central and outer body portions, and upper and lower shells configured to slide on the central bearing body portion and having the respective upper and lower central bearing surface portions formed thereon.

28. An artificial disc device for being implanted between upper and lower vertebrae, the artificial disc device comprising:

a central bearing for being inserted between the upper and lower vertebrae;

upper and lower arcuate central bearing surface portions of the central bearing that seat in arcuate recesses formed in the respective facing vertebral surfaces to resist migration of the central bearing from between the vertebrae;

an annular outer bearing extending around the central bearing so that the outer bearing is kept between the upper and lower vertebrae by the central bearing; and

upper and lower outer bearing surface portions of the outer bearing extending radially outward from the corresponding upper and lower bearing surface portions of the central bearing for sharing loads therewith to minimize highly localized loading on the bearing surface portions.

29. The artificial disc device of claim 28 wherein the outer annular bearing has an inner diameter, and the central bearing is sized to be in clearance with the annular bearing inner diameter to allow relative movement therebetween.

30. The artificial disc device of claim 28 wherein the central bearing has a generally spherical outer surface including the central bearing surface portions, and the outer bearing includes a central axial through opening in which the central bearing resides and an arcuate inner side surface extending about the opening and facing the spherical central bearing, the arcuate side surface generally having the same radius of curvature as that of the spherical outer surface to allow substantially free rotation of the central bearing seated in the vertebral recesses.

31. The artificial disc device of claim 30 wherein the spherical outer surface has a predetermined diameter, and the outer bearing upper and lower surface portions are axially spaced by a distance that is less than the predetermined diameter so that the central spherical bearing is axially enlarged relative to the annular outer bearing.

32. The artificial disc device of claim 28 wherein the upper and lower surface portions of the central bearing engaged in the vertebral recesses are axially spaced by a greater distance than the upper and lower surface portions of the outer bearing which have an axial spacing sized to maintain a generally anatomically correct spacing between the upper and lower vertebrae engaged therewith.

33. The artificial disc device of claim 28 wherein the upper and lower surface portions of the outer bearing have an arcuate configuration with a more gradual curvature than the arcuate surface portions of the central bearing for generally conforming to the shape of the facing vertebral surfaces.

34. The artificial disc device of claim 28 wherein the annular outer bearing has a generally wedged configuration including an axially enlarged section between the upper and lower surface portions for optimizing fit of the outer bearing between the vertebrae.

35. The artificial disc device of claim 28 wherein the outer annular bearing extends about a disc axis and comprises upper and lower annular plates with the upper bearing surface portion on the upper plate and the lower bearing surface portion on the lower plate, the plates being axially spaced and extending generally transverse to the disc axis.

36. The artificial disc device of claim 35 wherein the plates have a cushioning material in the axial space therebetween to provide for resilient shifting of the plates relative to each other and biasing the unloaded plates to a generally parallel orientation thereof.

37. The artificial disc device of claim 36 wherein the central bearing has a generally spherical outer surface including the arcuate surface bearing portions, and the annular plates each include a central opening having a maximum diameter that is less than that of the spherical outer surface for providing the axial spacing of the plates in close fit with the central bearing outer surface.

38. The artificial disc device of claim 28 wherein the outer annular bearing has a central axial through opening, and the central bearing has a body that is axially elongated to extend through the central opening with the upper and lower arcuate surface bearing portions extending axially beyond the corresponding upper and lower outer bearing surface portions.

39. The artificial disc device of claim 38 wherein the outer annular bearing is of resilient material and has an inner surface bounding the through opening, and the axially elongated body includes an outer side surface that is in close confronting relation to the annular bearing inner surface and which has an annular groove to provide a gap between the confronting bearing surfaces into which the resilient material of the outer annular bearing can deform when loaded.

40. The artificial disc device of claim 28 wherein the central bearing is of a harder material than the outer bearing to maintain conformity of the arcuate surface portions in the vertebral recesses.

41. The artificial disc device of claim 28 wherein the outer bearing is of resilient material to allow the outer bearing to resiliently deform under compressive loading forces.

42. The artificial disc device of claim 28 wherein the outer bearing has an outer wear layer including the bearing surface portions thereof, and an inner cushion portion with the outer wear layer being of harder material than the inner core cushion portion.

43. An artificial disc device for being implanted between axially spaced upper and lower vertebrae, the artificial disc device comprising:

upper and lower plate members for engaging facing surfaces of the respective upper and lower vertebrae;

a central projection on each of the plate members extending axially and having an arcuate surface thereon for sliding in an arcuate recess in the vertebrae with which the arcuate surface is slidingly engaged;

an annular load bearing member between the plate members for axially spacing the plate members and being of resilient material to allow shifting of the plate members toward and away from each other with resilient deformation of the annular member; and

a bumper member about which the annular member extends and being of a harder material than the annular member to limit deformation of the annular member.

44. The artificial disc device of claim 43 wherein the annular load bearing member is axially thicker than the bumper member so that there is space between the upper plate member and the bumper member during normal loading conditions of the spine.

45. The artificial disc device of claim 43 including low friction bearing surfaces between the annular member and the plate members to minimize wear therebetween.

46. The artificial disc device of claim 43 wherein the upper plate and lower plate include arcuate central projections extending toward each other, and the bumper member has upper and lower arcuate recesses configured for mating and sliding engagement with the corresponding upper plate and lower plate projections.

47. The artificial disc device of claim 43 including a sheath or bag for holding the plate members, annular load bearing member and bumper member together in assembled form during implantation.

48. The artificial disc device of claim 43 wherein the plate members and annular member include retaining structure therebetween that resists lateral and rotational shifting of the plate members relative to the annular member.

49. The artificial disc device of claim 48 wherein the retaining structure comprises annular grooves in one of the annular member and the plate members and projections in the other of the annular member and the plate members that extend into the grooves.

50. The artificial disc device of claim 43 wherein the annular member defines a central interior space in which the bumper member is loosely disposed and includes openings to the interior space and to exterior of the annular member to provide a flowpath therebetween.

51. The artificial device of claim 43 wherein the annular member and at least one of the plate members include a channel therebetween for providing fluid flow between the interior and exterior of the disc device.

52. The artificial disc device of claim 51 wherein the annular member has upper and lower surfaces facing the respective upper and lower plate members, and the channel includes a plurality of radially extending channels formed in the upper and lower surfaces of the resilient annular member.

53. The artificial disc device of claim 43 wherein the resilient material of the annular load bearing member comprises hydrogel.

54. An artificial disc device for being implanted between upper and lower vertebrae, the artificial disc device comprising:

upper and lower arcuate bearing shells for slidingly engaging against respective facing surfaces of the upper and lower vertebrae;

a central bearing portion having an arcuate outer surface that supports the shells for sliding thereon to allow for differential shifting between the relative movement of the shells and the engaged vertebrae and of the shells and the central bearing portion during vertebral movements; and

an annular outer bearing portion extending around the central bearing portion for load sharing with the bearing shells.

55. The artificial disc device of claim 54 wherein the central bearing portion has a generally spherical configuration and the shells have a dome configuration for sliding on the spherical central bearing portion.

56. The artificial disc device of claim 55 wherein the spherical central bearing portion has a predetermined diameter, and the dome shells have a maximum diameter that is less than the predetermined diameter.

57. The artificial disc device of claim 54 including a web wall that interconnects and spaces the central and outer bearing portions laterally from each other to keep interference between the sliding bearing shells and the outer bearing portion to a minimum.

58. The artificial disc device of claim 57 wherein the web wall is integral with the central and outer bearing portions.

59. The artificial disc device of claim 54 wherein the central bearing portion and annular outer bearing portion are laterally spaced from each other to form a gap therebetween in which the shells can slide and the annular bearing portion has an inner side surface that extends axially to maximize sizing of the recesses.

60. The artificial disc device of claim 54 wherein annular outer bearing portion is of resilient material and has an outer peripheral surface including upper and lower flanges and a concave groove between the flanges to optimize flexibility of the flanges under compressive loading.

61. The artificial disc device of claim 54 wherein the outer bearing portion includes a core of cushioning material for shock absorbtion and upper and lower bearing surfaces of hard material for wear resistance.

62. The artificial disc device of claim 54 wherein the central bearing portion includes an axial through opening, and the shells include projections that extend in the through opening and cooperate to limit compression of the central bearing portion and shifting of the shells axially toward each other.

63. The artificial disc device of claim 54 including a web wall interconnecting the bearing portions extending laterally therebetween, and the outer bearing portion includes an inner extension of the web wall and upper and lower arcuate bearing rings that support the respective upper and lower shells for sliding thereon and which are supported for lateral sliding on the web wall including the extension thereof.