Expandable interbody fusion device

• US 20060058880A1
• Filed: 08/25/2005
• Published: 03/16/2006
• Est. Priority Date: 08/25/2004
• Status: Active Grant

• Current Assignee: Spine Wave Incorporated
• Original Assignee: Spine Wave Incorporated
• Inventors: LoGuidice, Mark D., Nilsson, Carl Michael, Manzi, Richard, Savage, Daniel S., Paxson, Robert D., Pafford, John, Lipschultz, Tyler P., Logan, Joseph N., Wysocki, Steve
• Granted Patent: US 7,875,078 B2
• Time in Patent Office: Days
• US Class Current: 623/17.150
• CPC Class Codes: A61B 2017/0256 for the spine
• 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 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 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• 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 2002/30383 made by laterally inserting a protrusion, e.g. a rib into a complementarily-shaped groove
• CPC Class Codes: A61F 2002/30476 locked by an additional locking mechanism
• CPC Class Codes: A61F 2002/30492 using a locking pin
• CPC Class Codes: A61F 2002/3052 unrestrained in only one direction, e.g. moving unidirectionally
• CPC Class Codes: A61F 2002/30556 for adjusting thickness
• CPC Class Codes: A61F 2002/30599 stackable
• CPC Class Codes: A61F 2002/30601 telescopic
• CPC Class Codes: A61F 2002/30904 serrated profile, i.e. saw-toothed
• 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 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2250/0009 for adjusting thickness
• CPC Class Codes: A61F 2250/0063 Nested prosthetic parts

Abstract

An expandable interbody fusion device for implantation into the intradiscal space between two opposing vertebral bodies of a spine comprises a superior endplate member having an upper surface for engaging a superior vertebral body in a spine, and an inferior endplate member having a lower surface for engaging an inferior vertebral body in the spine. The superior endplate member and the inferior endplate member are releasably coupled and define a cavity therebetween. At least one expansion member is configured to be introduced into the cavity to move the superior endplate and the inferior endplate members relatively apart upon introduction and to thereby decouple the superior endplate member and the inferior endplate member. An inserter may be releasably coupled to the device to facilitate insertion of the device as well as to provide a track for insertion of the expansion members.

Claims

1. An expandable interbody fusion device for implantation into the intradiscal space

between two opposing vertebral bodies of a spine, comprising:

a superior endplate member having an upper surface for engaging a superior vertebral body in a spine;

an inferior endplate member having a lower surface for engaging an inferior vertebral body in said spine, said superior endplate member and said inferior endplate member being releasably coupled and defining a cavity therebetween; and

at least one expansion member configured to be introduced into said cavity to move said superior endplate and said inferior endplate member relatively apart upon introduction and to thereby decouple said superior endplate member and said inferior endplate member.

2. The fusion device of claim 1, wherein said superior endplate member has a pair of opposing spaced apart sidewalls depending downwardly from said upper surface.

3. The fusion device of claim 2, wherein said inferior endplate member has a pair of opposing spaced apart sidewalls projecting upwardly from said lower surface, said depending sidewalls of said superior endplate member and said projecting sidewalls of said inferior endplate member overlapping for an extent as said superior endplate member and said inferior end plate member are moved apart.

4. The fusion device of claim 3, wherein at least one of said sidewalls on one of said superior endplate member or said inferior endplate member comprises a projecting prong and an overlapping sidewall of the other of said superior endplate member or said inferior endplate member defines a complementary notch for receipt of said prong, said prong and said notch forming said releasable coupling between said superior endplate member and said inferior endplate member.

5. The fusion device of claim 4, wherein said superior endplate member has at least one end wall depending downwardly from said upper surface.

6. The fusion device of claim 5, wherein said inferior endplate member has at least one end wall projecting upwardly from said lower surface, said depending end wall of said superior endplate member and said projecting end wall of said inferior endplate member overlapping for an extent as said superior endplate member and said inferior endplate member are moved apart.

7. The fusion device of claim 1, wherein said upper surface of said superior endplate member and said lower surface of said inferior endplate member each comprise gripping surfaces for engagement with the respective superior and inferior vertebral bodies.

8. The fusion devices of claim 7, wherein said gripping surfaces are defined by ribs having a generally saw-toothed configuration.

9. The fusion device of claim 1, wherein at least one of said upper surface of said superior endplate member or said lower surface of said inferior endplate member is angled to provide a particular angle between said opposing vertebral bodies.

10. The fusion device of claim 9, wherein both said upper surface of said superior endplate member and said lower surface of said inferior member are angled.

11. The fusion device of claim 1, wherein at least one of said upper surface of said superior endplate member or said lower surface of said inferior endplate member is curved to provide anatomical support of the vertebral bodies.

12. The fusion device of claim 11, wherein both of said upper surface of said superior endplate member and said lower surface of said inferior member are curved.

13. The fusion device of claim 1, wherein said at least one expansion member is a generally flat wafer configured for sliding insertion into said cavity under sufficient pressure to move said superior endplate member and said inferior endplate member apart.

14. The fusion device of claim 13, wherein said wafer comprises a surface for cooperative engagement with at least said superior endplate member.

15. The fusion device of claim 14, wherein the device comprises a plurality of wafers slidably received in contact to form a stack of wafers within said cavity.

16. The fusion device of claim 15, wherein each of said wafers has an upper generally flat surface and a lower generally flat surface.

17. The fusion device of claim 16, wherein a lower flat surface of a wafer in said stack and an upper flat surface of a contacting wafer comprise complementary interdigitating configurations to provide at least lateral and rotational stability to said stack of wafers.

18. The fusion device of claim 17, wherein said complementary configurations are defined by a ridge on at least one of said wafer surfaces and a trough for receiving said ridge on a surface of a contacting wafer.

19. The fusion device of claim 1, wherein said superior endplate member and said inferior endplate member are each formed of biocompatible material.

20. An expandable interbody fusion device for implantation into the intradiscal space between two opposing vertebral bodies of a spine, comprising:

a superior endplate member having an upper surface for engaging a superior vertebral body in a spine;

an inferior endplate member having a lower surface for engaging an inferior vertebral body in said spine;

said superior endplate member and said inferior endplate member defining a cavity therebetween;

at least one expansion member configured to be introduced into said cavity and upon introduction to move said superior endplate member and said inferior endplate member relatively apart; and

said superior endplate member and said inferior endplate member defining cooperative surfaces that overlap for an extent as said superior endplate member and said inferior endplate member move apart to thereby provide stability to said device upon expansion.

21. The fusion device of claim 20, wherein said cooperative surfaces include a pair of opposing spaced apart sidewalls downwardly depending from said upper surface of said superior endplate member.

22. The fusion device of claim 21, wherein said cooperative surfaces include a pair of opposing spaced apart sidewalls upwardly projecting from said lower surface of said inferior endplate member that overlap with said sidewalls of said superior endplate member upon expansion of said device.

23. The fusion device of claim 20, wherein said cooperative surfaces include at least one downwardly depending end wall on said superior endplate member overlapping a surface on said inferior endplate member.

24. The fusion device of claim 23, wherein said overlapping surface on said inferior endplate member is an upwardly projecting end wall.

25. The fusion device of claim 20, wherein said at least one expansion member is a generally flat wafer configured for sliding insertion into said cavity under sufficient pressure to move said superior endplate member and said inferior member apart.

26. The fusion device of claim 25, wherein said wafer comprises at least one surface for cooperative engagement with a surface of one of said superior endplate member or said inferior endplate member.

27. The fusion device of claim 26, wherein the device comprises a plurality of wafers slidably received in contact to form a stack of wafers within said cavity.

28. The fusion device of claim 27, wherein said wafers comprise complementary interdigitating configurations to provide at least lateral and rotational stability to said stack of wafers.

29. The fusion device of claim 28, wherein said cooperative overlapping surfaces of said superior endplate member and said inferior endplate member define a releasable coupling breakable upon introduction of an expansion member.

30. The fusion device of claim 29, wherein said releasable coupling is defined by a prong on one of said overlapping surfaces and a complementary notch on the other of said overlapping surfaces.

31. An apparatus for use in restoring the anatomical height of a damaged or diseased disc space between two opposing vertebral bodies in a spine, comprising:

an expandable interbody fusion device according to claim 20;

and

an inserter releasably connected to said fusion device.

32. The apparatus of claim 31, wherein said inserter comprises a track along which said expansion element is conveyed for introduction into said cavity.

33. The apparatus of claim 32, further comprising a separable interface between said track and said fusion device.

34. The apparatus of claim 33, wherein said interface comprises a connector plate supported by said inferior endplate member.

35. The apparatus of claim 34, wherein said connector plate includes a support surface on one side for supporting said expansion member and at least one severable member on the other side for temporarily holding said track to said fusion device.

36. The apparatus of claim 35, further including a movable release plate supported by said track and having a cutting surface operable upon movement to sever said at least one severable member on said connector plate, to thereby allow removal of said track from said fusion device.

37. The apparatus of claim 36, wherein said device comprises a plurality of expansion members, each being a generally flat wafer and configured for slidable receipt to form a stack of wafers within the cavity of said device.

38. The apparatus of claim 37, wherein there are at least two severable members on said connector plate and wherein said release plate has at least two openings for respectively receiving said severable members.

39. The apparatus of claim 38, wherein the edges of said openings in said connector plate define said cutting surfaces.

40. The apparatus of claim 39, wherein said configuration of one of said openings is elongate relative to the other of said openings to thereby cause cutting of said severable members in a sequential manner upon movement of said release plate.

41. An expandable interbody fusion device for implantation into the intradiscal space between two opposing vertebral bodies of a spine, comprising:

a curved superior endplate member;

a curved inferior endplate member;

at least one of said superior endplate member or said inferior endplate member having a thickness at one side different from the thickness at the other side, defining thereby a lordotic angle between opposing vertebral bodies; and

at least one expansion member between said superior endplate member and said inferior endplate member, said at least one expansion member being of relatively constant thickness from one side to the other.

42. The fusion device of claim 41, wherein said at least one expansion member is defined by a plurality of stacked wafers.

43. The fusion device of claim 42, wherein both said superior endplate member and said inferior endplate member have a thickness on one side different from the thickness on said other side.

44. The fusion device of claim 42, wherein said device defines cooperative interlocking surfaces between said wafers.

45. The fusion device of claim 44, wherein said cooperative interlocking surfaces comprise dovetail configurations.

46. An expandable interbody fusion device for implantation into the intradiscal space between two opposing vertebral bodies of a spine, comprising:

a superior endplate member;

an inferior endplate member; and

a plurality of wafers stacked between said superior endplate member and said inferior endplate member, each of said wafers having a different thickness from side to side to thereby provide upon disposition between said superior endplate member and said inferior endplate member a lordotic angle between said vertebral bodies.

47. The fusion device of claim 46, wherein said device defines cooperative interlocking surfaces between said wafers.

48. The fusion device of claim 47, wherein said cooperative interlocking surfaces comprise dovetail configurations.

49. The fusion device of claim 46, wherein said superior and inferior endplate members are similarly curved.

50. A device for distracting a body tissue space between opposing tissue surfaces, comprising:

an upper plate having an outer surface configured to contact one of the opposing surfaces;

a lower plate having an outer surface configured to contact the other of the opposing surfaces, said lower plate having opposite side walls configured to removably support said upper plate thereon;

said upper and lower plates defining a cavity when said upper plate is supported on said lower plate,

said lower plate defining a wafer support surface for supporting at least one wafer within said cavity, and a channel communicating with said cavity and configured to receive a wafer conveyed therethrough for placement on said surface of said lower plate; and

said upper plate defining a contact surface for contacting a wafer within said cavity to displace said upper plate from said lower plate.

51. The device of claim 50, wherein:

said lower plate includes a lower end wall opposite said channel; and

said upper plate includes an upper end wall arranged to overlap said lower end wall when said upper plate is supported on said lower plate.

52. The device of claim 51, wherein said lower and upper end walls are sized to overlap when said upper plate is displaced from said lower plate.

53. The device of claim 50, further comprising at least one rib and mating recess releasably engaged between said upper plate and each side wall of said lower plate, whereby said at least one rib and mating recess are disengaged when said upper plate is displaced by the wafer.

54. The device of claim 50, in which wafers are sequentially transported through a track assembly, wherein said channel is configured to connect to the track assembly to receive wafers transported therethrough.

55. The device of claim 54, wherein said channel includes:

a wafer channel arranged to direct a wafer from the track assembly onto said wafer support surface; and

a connection mechanism, disposed within said cavity, for releasably connecting said lower plate to the track assembly.

56. The device of claim 55, wherein said connection mechanism includes:

a connection plate connected to said lower plate; and

a release plate disposed between and operable to disconnect said connection plate and said lower plate, said plate having a portion accessible through the track assembly.

57. The device of claim 56, wherein:

said connection plate includes a plurality of bosses projecting therefrom; and

said lower plate defines a like plurality of openings for receiving a corresponding one of said bosses therethrough.

58. The device of claim 57, wherein said bosses and openings form a press-fit engagement.

59. The device of claim 54, wherein said connection mechanism includes:

a plurality of bosses and

a plate having a portion accessible through the track assembly and a portion defining a like plurality of openings form a press-fit engagement.

60. The device of claim 59, wherein said bosses and openings form a press-fit engagement.

61. The device of claim 50, further including at least one wafer in said cavity and supported on said support surface of said lower plate and contacting said contact surface of said upper plate.

62. The device of claim 61, wherein said contact surface of said upper plate is configured for interlocking engagement with the wafer within said cavity.

63. The device of claim 62, further comprising a plurality of wafers stacked within said cavity, each wafer being configured for interlocking engagement with another wafer.