Expandable implant with interlocking walls

• US 6,808,537 B2
• Filed: 07/06/2001
• Issued: 10/26/2004
• Est. Priority Date: 07/07/2000
• Status: Expired due to Term

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Gary K. Michelson
• Inventors: Michelson, Gary Karlin
• Primary Examiner(s): Robert, Eduardo C.
• Application Number:
  US09/900,305
• Publication Number:
  US 20020010511A1
• Time in Patent Office: 1,208 Days
• Field of Search: 623/17.11, 623/17.13, 623/17.15, 623/17.16, 606/61
• US Class Current: 623/17.15
• CPC Class Codes: A61B 17/8042 the additional component being a cover over the screw head
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• 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 2/4455 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 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30187 D-shaped or half-disc-shaped
• CPC Class Codes: A61F 2002/30362 with possibility of relative movement between the protrusion and the recess
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30517 using a locking plate
• CPC Class Codes: A61F 2002/30556 for adjusting thickness
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30624 Hinged joint, e.g. with transverse axle restricting the movement
• CPC Class Codes: A61F 2002/30772 Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/3079 : Stepped or enlarged apertures, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/30836 : knurled
• CPC Class Codes: A61F 2002/3085 : with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30873 : Threadings machined on non-cylindrical external surfaces
• CPC Class Codes: A61F 2002/30904 : serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/30975 : made of two halves
• 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 2210/0014 : using shape memory or superelastic materials, e.g. nitinol
• 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 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0034 : D-shaped
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• 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 2310/00071 : Nickel or Ni-based alloys
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00359 : Bone or bony tissue
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

An interbody spinal fusion implant having an expandable height and interlocking side walls to maintain the increased height of the implant.

Claims

1. An interbody spinal fusion implant for insertion at least in part across at least a surgically corrected height of a disc space between two adjacent vertebral bodies of a spine, said implant comprising:

a mid-longitudinal axis;

an upper member having a portion adapted for placement toward and into contact with one of the adjacent vertebral bodies, said upper member having at least one opening adapted to communicate with one of the adjacent vertebral bodies, said upper member having a proximal end and a distal end;

a lower member having a portion adapted for placement toward and into contact with the other of the adjacent vertebral bodies, said lower member having at least one opening adapted to communicate with the other of the adjacent vertebral bodies, said openings of said upper and lower members being in communication with one another and being adapted to permit growth of bone from adjacent vertebral body to adjacent vertebral body through said implant and being sufficiently sized and located to allow for interbody spinal fusion through said implant, said lower member having a proximal end and a distal end corresponding to said proximal end and said distal end of said upper member, respectively, and a length between said proximal and distal ends, said upper and lower members articulating therebetween about a fixed axis generally transverse to the mid-longitudinal axis and adjacent one of said proximal ends and said distal ends of said upper and lower members to allow for expansion of said implant, said upper and lower members having a first position relative to one another allowing for a collapsed implant height and a second position relative to one another allowing for an increased height; and

each of said upper and lower members having side walls, each of said side walls having a length, said side walls being adapted to cooperatively engage one another along at least a portion of the length of said side walls to hold at least a portion of said upper and lower members apart so as to maintain the increased height of said implant and resist the collapse of said implant to the collapsed implant height when said implant is in a final deployed position.

2. The implant of claim 1, wherein said side walls are at least in part overlapping.

3. The implant of claim 2, wherein said side walls of at least one of said upper and lower members flex when said implant is moved from the first position to the second position.

4. The implant of claim 2, wherein said side walls of both of said upper and lower members flex when said implant is moved from the first position to the second position.

5. The implant of claim 2, wherein at least one of said side walls of at least one of said upper and lower members spring from a position closer to the mid-longitudinal axis of said implant to a position further away from the mid-longitudinal axis when said implant is moved from the first position to the second position.

6. The implant of claim 2, wherein at least one of said side walls of at least one of said upper and lower members spring from a position further from the mid-longitudinal axis of said implant to a position closer to the mid-longitudinal axis when said implant is moved from the first position to the second position.

7. The implant of claim 2, wherein at least a portion of at least one of said side walls of at least one of said upper and lower members rotates along an arc of an axis that is parallel to the mid-longitudinal axis of said implant when said implant is moved from the first position to the second position.

8. The implant of claim 2, wherein said side walls of said upper and lower members have cooperatively engaging stepped surfaces.

9. The implant of claim 1, wherein said side walls are aligned parallel with the mid-longitudinal axis of said implant.

10. The implant of claim 1, wherein said side walls are adapted to maintain said portions of said upper and lower members at an angled orientation relative to one another when said implant is in the second position.

11. The implant of claim 1, wherein said side walls are adapted to maintain said portions of said upper and lower members at a parallel orientation relative to one another when said implant is in the second position.

12. The implant of claim 1, wherein one of said upper and lower members has an interior wall, which is unexposed, extending therefrom toward the other of said upper and lower members when said implant is in an initial insertion position, and when said implant is in a final position said implant has a shape such that each of said portions of said upper and lower members are separated by at least a portion of said interior wall, which now has an exposed side.

13. The implant of claim 1, wherein said upper and lower members are configured to cooperate with one another so as to stop said upper and lower members from being moved apart from one another more than a predetermined distance.

14. The implant of claim 1, wherein said implant has a side surface when in a final position that is contoured to cooperate with another implant.

15. The implant of claim 1, wherein said implant is adapted to cooperatively engage a tool used to move said implant from an initial position to a final position to increase the height of said implant, said tool not being a part of said implant and being removed from engagement with said implant after moving said implant into the final position.

16. The implant of claim 1, wherein at least one of said side walls is a form of Nitonal.

17. The implant of claim 1, wherein said articulation allows for expansion.

18. The implant of claim 1, wherein said articulation allows for limited expansion.

19. The implant of claim 1, wherein said articulation is formed by said upper and lower members interdigitating so as to cooperatively engage.

20. The implant of claim 1, wherein said articulation is configured such that to permit articulation and disarticulation engagement occurs when said upper and lower members are substantially perpendicular to one another.

21. The implant of claim 1, wherein said articulation is configured to remain engaged within a range of movement of said upper and lower members resulting from positioning said implant in the second position.

22. The implant of claim 1, further comprising at least a portion of a bone-engaging projection formed on the exterior of each of said opposed portions of said upper and lower members for engaging the adjacent vertebral bodies and to facilitate securing said implant into the spine.

23. The implant of claim 22, wherein said bone-engaging projection is at least a portion of a helical thread to facilitate securing said implant into the spine by at least in part rotating said implant about the longitudinal axis of said implant.

24. The implant of claim 22, wherein said bone-engaging projection is adapted for linear insertion.

25. The implant of claim 1, further comprising at least a portion of a bone-engaging projection adapted for linear insertion formed on the exterior of each of said portions of said upper and lower members for penetrably engaging the adjacent vertebral bodies and to facilitate securing said implant into the spine.

26. The implant of claim 23, wherein said bone-engaging projection is selected from one of a ratchet, a surface roughening, and a knurling.

27. The implant of claim 1, wherein said portions of said upper and lower members are at least in part arcuate and adapted for placement toward and at least in part within one of the adjacent vertebral bodies.

28. The implant of claim 27, wherein said arcuate portions of said upper and lower members in the first position are parallel to one another over a substantial portion of the length of said implant and form at least a portion of a cylinder along the length of said implant.

29. The implant of claim 27, wherein said arcuate portions of said upper and lower members in the first position are angled to one another over a substantial portion of the length of said implant and form at least a portion of a frusto-conical shape along the length of said implant.

30. The implant of claim 27, wherein said arcuate portions of said upper and lower members in the first position are angled to one another over a substantial portion of the length of said implant and form at least a portion of the shape of a cylinder split along a horizontal plane through its mid-longitudinal axis with said upper member and said lower member being angled to each other along the length of said implant.

31. The implant of claim 27, further comprising a second interbody spinal fusion implant comprising:

an upper member having a portion being at least in part arcuate adapted for placement toward and at least in part within one of the adjacent vertebral bodies, said upper member having at least one opening adapted to communicate with one of the adjacent vertebral bodies, said upper member having a proximal end and a distal end;

a lower member having a portion being at least in part arcuate adapted for placement toward and at least in part within the other of the adjacent vertebral bodies, said lower member having at least one opening adapted to communicate with the other of the adjacent vertebral bodies, said openings of said upper and lower members being in communication with one another and adapted for permitting for the growth of bone from adjacent vertebral body to adjacent vertebral body through said implant and being sufficiently sized and located to allow for interbody spinal fusion through said implant, said lower member having a proximal end and a distal end corresponding to said proximal end and said distal end of said upper member, respectively, and a length between said proximal and distal ends; and

at least a portion of a bone-engaging projection formed on the exterior of each of said opposed arcuate portions of said upper and lower members for penetrably engaging the adjacent vertebral bodies and to facilitate securing said implant into the spine, said first and second implants when in side-to-side contact having a combined width substantially less than the combined heights as measured from the upper to the lower bone-engaging surfaces of said first and second implants.

32. The implant of claim 1, wherein said portions of said upper and lower members are non-arcuate along a substantial portion of the length of said implant.

33. The implant of claim 1, wherein said implant is substantially parallelepiped.

34. The implant of claim 1, further comprising at least one blocker adapted to cooperatively engage and hold at least a portion of said upper and lower members apart so as to maintain the increased height of said implant and resist the collapse of said implant to the collapsed implant height when said implant is in a final deployed position.

35. The implant of claim 34, wherein said blocker pivotally attaches to one of said upper and lower members and is adapted to pivot into cooperative engagement with another of said one of said upper and lower members, said blocker being adapted to hold at least a portion of said upper and lower members apart so as to maintain the increased height of said implant and resist the collapse of said implant to the collapsed implant height when said implant is in a final deployed position.

36. The implant of claim 34, wherein said implant having a width and said blocker having a width less than the width of said implant.

37. The implant of claim 34, wherein said blocker is a portion of one of said ends of said upper and lower members.

38. The implant of claim 34, wherein said blocker is located at least in part between said upper and lower members.

39. The implant of claim 34, wherein said blocker is located proximate at least one of said ends of said upper and lower members.

40. The implant of claim 34, wherein said blocker is adapted to cooperatively engage a tool used to move said blocker from an initial position to a final position to increase the height of said implant, said tool not being a part of said implant and being removed from said implant after moving said blocker into the final position.

41. The implant of claim 34, wherein each of said upper and lower members have a track configured to permit said blocker to seat therein.

42. The implant of claim 34, wherein said blocker moves said portions of said upper and lower members from a parallel orientation to an angled orientation relative to one another.

43. The implant of claim 34, wherein said blocker moves said portions of said upper and lower members from a first angled orientation to a second angled orientation relative to one another.

44. The implant of claim 34, wherein said articulation is at one of said proximal end and said distal end of said upper and lower members opposite said blocker.

45. The implant of claim 34, further comprising a second blocker located between said upper and lower members for holding at least a portion of the upper and lower members apart where said second expander is located.

46. The implant of claim 34, wherein said blocker is an expander adapted to expand said implant from a first collapsed height to a second expanded height when moved from a first to a second position.

47. The implant of claim 46, wherein said implant has a longitudinal axis and said expander rotates in a plane generally perpendicular to the longitudinal axis of said implant to increase the height of said implant.

48. The implant of claim 46, wherein said expander has a fixed shape during movement from an initial insertion position to a final deployed position within said implant.

49. The implant of claim 46, further comprising a second expander located between said upper and lower members for moving at least a portion of the upper and lower members away from one another to increase the maximum height of said implant where said second expander is located.

50. The implant of claim 49, wherein said second expander rotates to increase the height of said implant.

51. The implant of claim 49, wherein said second expander has a first h eight corresponding to the height of said second expander when said implant is initially inserted into the spine, said second expander having a second height corresponding to the height of said second expander when said second expander is moved into a final deployed position to increase the height of said implant, said second height being greater than said first height.

52. The implant of claim 34, wherein said blocker is an expander having an external thread, each of said upper and lower members having a threaded converging portion adapted to cooperate with said external thread of said expander to expand said implant from a first collapsed height to a second expanded height when said expander is rotated from a first to a second position.

53. The implant of claim 1, further comprising a hollow defined between said upper and lower members in communication with said openings in each of said upper and lower members, said hollow being adapted to receive fusion-promoting substances.

54. The implant of claim 53, wherein said hollow has a width that is unobstructed by any mechanism expanding said implant.

55. The implant of claim 1, wherein said implant has a constant width in both the first position and the second position.

56. The implant of claim 1, wherein said implant has an interior, at least one of said upper and lower members has a screw hole passing therethrough adapted to receive a screw passing from said interior of said implant into one of the adjacent vertebral bodies.

57. The implant of claim 56, wherein each of said upper and lower members has at least one screw hole passing therethrough adapted to receive a screw passing from said interior of said implant into the adjacent vertebral body in contact with each of said upper and lower members respectively.

58. The implant of claim 56, further comprising at least one screw adapted to pass from said interior of said implant through said screw hole and into the adjacent vertebral body to anchor said implant to the adjacent vertebral body.

59. The implant of claim 1, wherein said implant is made of an artificial material that is harder than bone.

60. The implant of claim 1, wherein said implant comprises bone.

61. The implant of claim 60, wherein said bone includes cortical bone.

62. The implant of claim 1, wherein said implant comprises bone growth promoting material.

63. The implant of claim 62, wherein said bone growth promoting material is selected from one of bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

64. The implant of claim 1, wherein said implant is treated with a bone growth promoting substance.

65. The implant of claim 1, wherein said implant is a source of osteogenesis.

66. The implant of claim 1, wherein said implant is at least in part bioabsorbable.

67. The implant of claim 1, wherein said implant comprises a material selected from one of plastic and ceramic.

68. The implant of claim 1, wherein said implant is formed of a material that intrinsically participates in the growth of bone from adjacent vertebral body to adjacent vertebral body through said implant.

69. The implant of claim 1, in combination with a chemical substance to inhibit scar formation.

70. The implant of claim 1, in combination with a fusion promoting substance.

71. The implant of claim 70, wherein said fusion promoting substance includes at least one of bone, bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

72. An interbody spinal fusion implant for insertion at least in part across at least a surgically corrected height of a disc space between two adjacent vertebral bodies of a spine, said implant comprising:

a mid-longitudinal axis;

an upper member having a portion adapted for placement toward and into contact with one of the adjacent vertebral bodies, said upper member having at least one opening adapted to communicate with one of the adjacent vertebral bodies, said upper member having a proximal end and a distal end;

a lower member having a portion adapted for placement toward and into contact with the other of the adjacent vertebral bodies, said lower member having at least one opening adapted to communicate with the other of the adjacent vertebral bodies, said openings of said upper and lower members being in communication with one another and being adapted to permit growth of bone from adjacent vertebral body to adjacent vertebral body through said implant and being sufficiently sized and located to allow for interbody spinal fusion through said implant, said lower member having a proximal end and a distal end corresponding to said proximal end and said distal end of said upper member, respectively, and a length between said proximal and distal ends, said upper and lower members articulating therebetween adjacent one of said proximal ends and said distal ends of said upper and lower members and allowing for expansion of said implant, said upper and lower members having a first position relative to one another allowing for a collapsed implant height and a second position relative to one another allowing for an increased height; and

each of said upper and lower members having side walls with a length, said side walls being at least in part overlapping and being adapted to cooperatively engage one another along at least a portion of the length of said side walls to hold at least a portion of said upper and lower members apart so as to maintain the increased height of said implant and resist the collapse of said implant to the collapsed implant height when said implant is in a final deployed position, said side walls of said upper and lower members having cooperatively engaging stepped surfaces that have interdigitating projections and detents.

73. The implant of claim 72, wherein said side walls having said projections have two projections.

74. The implant of claim 73, wherein said side walls having said detents have three detents.

75. The implant of claim 72, wherein said side walls having detents have more detents than said cooperatively engaging side walls having projections have projections to permit said implant to move from the first position to the second position when said projections are moved from engagement with a first set of said detents to a second set of said detents.

76. The implant of claim 72, wherein during movement of said implant from the first position to the second position said side walls having detents have at least one detent that narrows during movement of said side wall having detents.

77. The implant of claim 76, wherein said side wall having detents moves into alignment and engagement with said projections of said wall having projections to increase the height of said implant during movement of said implant from the first position to the second position.

78. The implant of claim 72, wherein at least one of said side wails of at least one of said upper and lower members spring from a position closer to the mid-longitudinal axis of said implant to a position further away from the mid-longitudinal axis when said implant is moved from the first position to the second position.

79. The implant of claim 72, wherein at least one of said side walls of at least one of said upper and lower members spring from a position further from the mid-longitudinal axis of said implant to a position closer to the mid-longitudinal axis when said implant is moved from the first position to the second position.

80. The implant of claim 72, wherein at least a portion of at least one of said side walls of at least one of said upper and lower members rotates along an arc of an axis that is parallel to the mid-longitudinal axis of said implant when said implant is moved from the first position to the second position.

81. The implant of claim 72, wherein said side walls are aligned parallel with the mid-longitudinal axis of said implant.

82. The implant of claim 72, wherein said side walls are adapted to maintain said portions of said upper and lower members at an angled orientation relative to one another when said implant is in the second position.

83. The implant of claim 72, wherein said upper and lower members are configured to cooperate with one another so as to stop said upper and lower members from being moved apart from one another more than a predetermined distance.

84. The implant of claim 72, further comprising at least a portion of a bone-engaging projection formed on the exterior of each of said opposed portions of said upper and lower members for engaging the adjacent vertebral bodies and to facilitate securing said implant into the spine.

85. The implant of claim 84, wherein said bone-engaging projection is at least a portion of a helical thread to facilitate securing said implant into the spine by at least in part rotating said implant about the longitudinal axis of said implant.

86. The implant of claim 84, wherein said bone-engaging projection is adapted for linear insertion.

87. The implant of claim 84, wherein said bone-engaging projection is selected from one of a ratchet, a surface roughening, and a knurling.

88. The implant of claim 72, wherein said portions of said upper and lower members are at least in part arcuate and adapted for placement toward and at least in part within one of the adjacent vertebral bodies.

89. The implant of claim 72, wherein at least one of said side walls is a form of Nitonal.

90. The implant of claim 72, wherein said implant comprises bone growth promoting material.

91. The implant of claim 90, wherein said bone growth promoting material is selected from one of bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

92. The implant of claim 72, wherein said implant is at least in part bioabsorbable.

93. The implant of claim 72, combination with a chemical substance to inhibit scar formation.

94. The implant of claim 72, in combination with a fusion promoting substance.

95. The implant of claim 94, wherein said fusion promoting substance includes at least one of bone, bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

96. The implant of claim 72, further comprising a cap for closing one of said proximal end and said distal end of said upper and lower members, said cap having an exterior surface and an interior surface.

97. An interbody spinal fusion implant for insertion at least in part across at least a surgically corrected height of a disc space between two adjacent vertebral bodies of a spine, said implant comprising:

a mid-longitudinal axis;

an upper member having a portion adapted for placement toward and into contact with one of the adjacent vertebral bodies, said upper member having at least one opening adapted to communicate with one of the adjacent vertebral bodies, said upper member having a proximal end and a distal end;

a lower member having a portion adapted for placement toward and into contact with the other of the adjacent vertebral bodies, said lower member having at least one opening adapted to communicate with the other of the adjacent vertebral bodies, said openings of said upper and lower members being in communication with one another and being adapted to permit growth of bone from adjacent vertebral body to adjacent vertebral body through said implant and being sufficiently sized and located to allow for interbody spinal fusion through said implant, said lower member having a proximal end and a distal end corresponding to said proximal end and said distal end of said upper member, respectively, and a length between said proximal and distal ends, said upper and lower members articulating therebetween adjacent one of said proximal ends and said distal ends of said upper and lower members and allowing for expansion of said implant, said upper and lower members having a first position relative to one another allowing for a collapsed implant height and a second position relative to one another allowing for an increased height;

each of said upper and lower members having side walls, each of said side walls having a length, said side walls being adapted to cooperatively engage one another along at least a portion of the length of said side walls to hold at least a portion of said upper and lower members apart so as to maintain the increased height of said implant and resist the collapse of said implant to the collapsed implant height when said implant is in a final deployed position; and

a cap for closing one of said proximal end and said distal end of said upper and lower members, said cap having an exterior surface and an interior surface.

98. The implant of claim 97, wherein said interior surface of said cap has spaced slots about its circumference to facilitate a snap fit of said cap into said implant.

99. The implant of claim 97, wherein at least one of said side walls of at least one of said upper and lower members spring from a position closer to the mid-longitudinal axis of said implant to a position further away from the mid-longitudinal axis when said implant is moved from the first position to the second position.

100. The implant of claim 97, wherein at least one of said side walls of at least one of said upper and lower members spring from a position further from the mid-longitudinal axis of said implant to a position closer to the mid-longitudinal axis when said implant is moved from the first position to the second position.

101. The implant of claim 97, wherein at least a portion of at least one of said side walls of at least one of said upper and lower members rotates along an arc of an axis that is parallel to the mid-longitudinal axis of said implant when said implant is moved from the first position to the second position.

102. The implant of claim 97, wherein said side walls of said upper and lower members have cooperatively engaging stepped surfaces.

103. The implant of claim 97, wherein said side walls are aligned parallel with the mid-longitudinal axis of said implant.

104. The implant of claim 97, wherein said side walls are adapted to maintain said portions of said upper and lower members at an angled orientation relative to one another when said implant is in the second position.

105. The implant of claim 97, wherein said upper and lower members are configured to cooperate with one another so as to stop said upper and lower members from being moved apart from one another more than a predetermined distance.

106. The implant of claim 97, further comprising at least a portion of a bone-engaging projection formed on the exterior of each of said opposed portions of said upper and lower members for engaging the adjacent vertebral bodies and to facilitate securing said implant into the spine.

107. The implant of claim 106, wherein said bone-engaging projection is at least a portion of a helical thread to facilitate securing said implant into the spine by at least in part rotating said implant about the longitudinal axis of said implant.

108. The implant of claim 106, wherein said bone-engaging projection is adapted for linear insertion.

109. The implant of claim 106, wherein said bone-engaging projection is selected from one of a ratchet, a surface roughening, and a knurling.

110. The implant of claim 97, wherein said portions of said upper and lower members are at least in part arcuate and adapted for placement toward and at least in part within one of the adjacent vertebral bodies.

111. The implant of claim 97, wherein at least one of said side walls is a form of Nitonal.

112. The implant of claim 97, wherein said implant comprises bone growth promoting material.

113. The implant of claim 112, wherein said bone growth promoting material is selected from one of bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

114. The implant of claim 97, wherein said implant is at least in part bioabsorbable.

115. The implant of claim 97, in combination with a chemical substance to inhibit scar formation.

116. The implant of claim 97, in combination with a fusion promoting substance.

117. The implant of claim 116, wherein said fusion promoting substance includes at least one of bone, bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

118. An interbody spinal fusion implant for insertion at least in part across at least a surgically corrected height of a disc space between two adjacent vertebral bodies of a spine, said implant comprising:

a mid-longitudinal axis;

an upper member having a portion adapted for placement toward and into contact with one of the adjacent vertebral bodies, said upper member having at least one opening adapted to communicate with one of the adjacent vertebral bodies, said upper member having a proximal end and a distal end;

a lower member having a portion adapted for placement toward and into contact with the other of the adjacent vertebral bodies, said lower member having at least one opening adapted to communicate with the other of the adjacent vertebral bodies, said openings of said upper and lower members being in communication with one another and being adapted to permit growth of bone from adjacent vertebral body to adjacent vertebral body through said implant and being sufficiently sized and located to allow for interbody spinal fusion through said implant, said lower member having a proximal end and a distal end corresponding to said proximal end and said distal end of said upper member, respectively, and a length between said proximal and distal ends, said upper and lower members having a first position relative to one another allowing for a collapsed implant height and a second position relative to one another allowing for an increased height; and

each of the upper and lower members having side walls, each of said side walls having a length, said side walls being adapted to cooperatively engage one another along a substantial portion of the length of said side walls to hold at least a portion of said upper and lower members apart so as to maintain the increased height of said implant and resist the collapse of said implant to the collapsed implant height when said implant is in a final deployed position, at least one of said side walls of at least one of said upper and lower members springing from a position closer to the mid-longitudinal axis of said implant to a position further away from the mid-longitudinal axis when said implant is moved from the first position to the second position.

119. The implant of claim 118, in combination with a fusion promoting substance.

120. The implant of claim 119, wherein said fusion promoting substance includes at least one of bone, bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

121. The implant of claim 118, wherein at least a portion of at least one of said side walls of at least one of said upper and lower members rotates along an arc of an axis that is parallel to the mid-longitudinal axis of said implant when said implant is moved from the first position to the second position.

122. The implant of claim 118, wherein said side walls of said upper and lower members have cooperatively engaging stepped surfaces.

123. The implant of claim 118, wherein said side walls are aligned parallel with the mid-longitudinal axis of said implant.

124. The implant of claim 118, wherein said side walls are adapted to maintain said portions of said upper and lower members at an angled orientation relative to one another when said implant is in the second position.

125. The implant of claim 118, wherein said upper and lower members are configured to cooperate with one another so as to stop said upper and lower members from being moved apart from one another more than a predetermined distance.

126. The implant of claim 118, further comprising at least a portion of a bone-engaging projection formed on the exterior of each of said opposed portions of said upper and lower members for engaging the adjacent vertebral bodies and to facilitate securing said implant into the spine.

127. The implant of claim 126, wherein said bone-engaging projection is at least a portion of a helical thread to facilitate securing said implant into the spine by at least in part rotating said implant about the longitudinal axis of said implant.

128. The implant of claim 126, wherein said bone-engaging projection is adapted for linear insertion.

129. The implant of claim 126, wherein said bone-engaging projection is selected from one of a ratchet, a surface roughening, and a knurling.

130. The implant of claim 118, wherein said portions of said upper and lower members are at least in part arcuate and adapted for placement toward and at least in part within one of the adjacent vertebral bodies.

131. The implant of claim 118, wherein at least one of said side walls is a form of Nitonal.

132. The implant of claim 118, wherein said implant comprises bone growth promoting material.

133. The implant of claim 132, wherein said bone growth promoting material is selected from one of bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

134. The implant of claim 118, wherein said implant is at least in part bioabsorbable.

135. The implant of claim 118, in combination with a chemical substance to inhibit scar formation.

136. The implant of claim 118, further comprising a cap for closing one of said proximal end and said distal end of said upper and lower members, said cap having an exterior surface and an interior surface.

137. An interbody spinal fusion implant for insertion at least in part across at least a surgically corrected height of a disc space between two adjacent vertebral bodies of a spine, said implant comprising:

a mid-longitudinal axis;

an upper member having a portion adapted for placement toward and into contact with one of the adjacent vertebral bodies, said upper member having at least one opening adapted to communicate with one of the adjacent vertebral bodies, said upper member having a proximal end and a distal end;

a lower member having a portion adapted for placement toward and into contact with the other of the adjacent vertebral bodies, said lower member having at least one opening adapted to communicate with the other of the adjacent vertebral bodies, said openings of said upper and lower members being in communication with one another and being adapted to permit growth of bone from adjacent vertebral body to adjacent vertebral body through said implant and being sufficiently sized and located to allow for interbody spinal fusion through said implant, said lower member having a proximal end and a distal end corresponding to said proximal end and said distal end of said upper member, respectively, and a length between said proximal and distal ends, said upper and lower members having a first position relative to one another allowing for a collapsed implant height and a second position relative to one another allowing for an increased height and

each of said upper and lower members having side walls, each of said side walls having a length, each of said side walls of said upper member having an exterior surface, an interior surface opposite said exterior surface, and a lower surface therebetween, each of said side walls of said lower member having an exterior surface, an interior surface opposite said exterior surface, and an upper surface therebetween, said lower surfaces of said side walls of said upper member and said upper surfaces of said side walls of said lower member being adapted to cooperatively engage one another along at least a portion of the length of said side walls to hold at least a portion of said upper and lower members apart so as to maintain the increased height of said implant and resist the collapse of said implant to the collapsed implant height when said implant is in a final deployed position.

138. The implant of claim 137, wherein at least one of said side walls of at least one of said upper and lower members spring from a position closer to the mid-longitudinal aids of said implant to a position further away from the mid-longitudinal axis when said implant is moved from the first position to the second position.

139. The implant of claim 137, wherein at least one of said side walls of at least one of said upper and lower members spring from a position further from the mid-longitudinal axis of said implant to a position closer to the mid-longitudinal aids when said implant is moved from the first position to the second position.

140. The implant of claim 137, wherein at least a portion of at least one of said side walls of at least one of said upper and lower members rotates along an arc of an axis that is parallel to the mid-longitudinal axis of said implant when said implant is moved from the first position to the second position.

141. The implant of claim 137, wherein said side walls of said upper and lower members have cooperatively engaging stepped surfaces.

142. The implant of claim 137, wherein said side walls are aligned parallel with the mid-longitudinal axis of said implant.

143. The implant of claim 137, wherein said side walls are adapted to maintain said portions of said upper and lower members at an angled orientation relative to one another when said implant is in the second position.

144. The implant of claim 137, wherein said upper and lower members are configured to cooperate with one another so as to stop said upper and lower members from being moved apart from one another more than a predetermined distance.

145. The implant of claim 137, further comprising at least a portion of a bone-engaging projection formed on the exterior of each of said opposed portions of said upper and lower members for engaging the adjacent vertebral bodies and to facilitate securing said implant into the spine.

146. The implant of claim 145, wherein said bone-engaging projection is at least a portion of a helical thread to facilitate securing said implant into the spine by at least in part rotating said implant about the longitudinal axis of said implant.

147. The implant of claim 145, wherein said bone-engaging projection is adapted for linear insertion.

148. The implant of claim 145, wherein said bone-engaging projection is selected linear insertion.

149. The implant of claim 137, wherein said portions of said upper and lower members are at least in part arcuate and adapted for placement toward and at least in part within one of the adjacent vertebral bodies.

150. The implant of claim 137, wherein at least one of said side walls is a form of Nitonal.

151. The implant of claim 137, wherein said implant comprises bone growth promoting material.

152. The implant of claim 151, wherein said bone growth promoting material is selected from one of bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

153. The implant of claim 137, wherein said implant is at least in part bioabsorbable.

154. The implant of claim 137, in combination with a chemical substance to inhibit scar formation.

155. The implant of claim 137, in combination with a fusion promoting substance.

156. The implant of claim 155, wherein said fusion promoting substance includes at least one of bone, bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

157. The implant of claim 137, further comprising a cap for closing one of said proximal end and said distal end of said upper and lower members, said cap having an exterior surface and an interior surface.