INTERVERTEBRAL SPACER

• US 20020077700A1
• Filed: 06/12/2000
• Published: 06/20/2002
• Est. Priority Date: 06/12/2000
• Status: Active Grant

• Current Assignee: Ortho Development Corporation (Japan Medical Dynamic Marketing, Inc.)
• Original Assignee: Ortho Development Corporation (Japan Medical Dynamic Marketing, Inc.)
• Inventors: Ogilvie, James A., Varga, Peter Pal
• Granted Patent: US 6,579,318 B2
• Time in Patent Office: Days
• US Class Current: 623/17.11
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30774 internally-threaded
• CPC Class Codes: A61F 2002/30828 parallel
• CPC Class Codes: A61F 2002/4627 with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2230/0015 Kidney-shaped, e.g. bean-shaped
• 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: Y10S 623/908 Bone

Abstract

Abstract of the Disclosure

An intervertebral spacer adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc. The spacing member includes an external, non-porous, concavo-convex contour with respect to one dimension of said spacing member. The spacing member is preferably constructed from a rigid, non-resilient load-bearing material that is incapable of elastic deformation. The spacing member is inserted with the aid of a sheathed trocar device that is releasably attached to the spacer, to enable implantation and selective positioning of the spacer by the surgeon from the posterior side of the spine, without the need to retract the dural nerve or the posterior longitudinal ligament.

Claims

1. What is claimed is:

47. An intervertebral spacing implant comprising;

a spacing member adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc, said spacing member further comprising an external, concavo-convex contour with respect to one dimension of said spacing member;

wherein the spacing member is either inherently non-porous or is otherwise rendered non-porous, and is constructed from a rigid, non-resilient load-bearing material; and

wherein the spacing member defines an imaginary arcuate centerline residing between opposing sides of the external concavo-convex contour of said spacing member, said arcuate centerline forming less than half a circle.

35. An intervertebral spacing implant comprising:

a spacing member adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc, said spacing member further comprising an external, concavo-convex contour with respect to one dimension of said spacing member;

wherein the spacing member is either inherently non-porous or is otherwise rendered non-porous, and is constructed from a rigid, non-resilient load-bearing material;

wherein the spacing member includes an anterior wall and a posterior wall, and wherein the anterior wall and the posterior wall of the spacing member are each linear in a vertical dimension; and

wherein the spacing member further comprises a length that is greater in length than a thickness at a thickest part of the spacing member, and a width that is greater in width than said thickness at said thickest part.

56. An intervertebral spacing implant comprising:

a spacing member adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc, said spacing member further comprising an external, concavo-convex contour with respect to one dimension of said spacing member;

wherein the spacing member defines an imaginary arcuate centerline extending between opposing free ends, said spacing member tapering in thickness in a direction toward one of said free ends such that the thickness at one end is greater than the thickness at the other end.

11. The intervertebral spacing implant of claim 56, wherein the thickness of the spacing member is defined by a perimeter wall that constitutes the concave side and the convex side of the external concavo-convex contour of said spacing member.

89. The intervertebral spacing implant of claim 134, wherein the spacing member further comprises an upper surface, and wherein the tapered external shape of the spacing member is such that the upper surface of said spacing member defines a first acute angle with respect to a plane that is orthogonal to the convex side of the spacing member.

93. An intervertebral spacing implant comprising:

a spacing member adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc, said spacing member further comprising an external, concavo-convex contour with respect to one dimension of said spacing member;

said spacing member further comprising an upper surface and a lower surface, wherein at least one of said surfaces is multi-planar including at least two nonparallel planes.

3. The intervertebral spacing implant of claim 48, wherein the spacing member comprises titanium.

48. The intervertebral spacing implant of claim 93, wherein said attachment means for releasably attaching positioning means to said spacing member comprises a threaded bore.

94. The intervertebral spacing implant of claim 139, wherein the spacing member is either inherently non-porous or is otherwise rendered non-porous.

95. The intervertebral spacing implant of claim 139, wherein the spacing member is constructed from a rigid, non-resilient load-bearing material.

96. The intervertebral spacing implant of claim 139, wherein the spacing member defines an imaginary arcuate centerline extending between opposing free ends, wherein the arcuate centerline forms less than half a circle.

6. The intervertebral spacing implant of claim 51, wherein the anterior wall and the posterior wall of the spacing member are each linear in a vertical dimension.

51. The intervertebral spacing implant of claim 96, wherein the spacing member includes a lower surface that forms a second acute angle with respect to a horizontal plane, said second acute angle being in a range of approximately two degrees to eight degrees.

97. The intervertebral spacing implant of claim 139, wherein the spacing member comprises metal.

7. The intervertebral spacing implant of claim 52, wherein the concavo-convex contour comprises a concave posterior side, and a convex anterior side disposed in a substantially parallel orientation with respect to the concave posterior side.

52. The intervertebral spacing implant of claim 97, wherein the first acute angle and the second acute angle are each approximately four degrees with respect to a horizontal plane, for a total continuous taper of approximately eight degrees.

98. The intervertebral spacing implant of claim 143, wherein the spacing member comprises titanium.

99. The intervertebral spacing implant of claim 139, wherein the spacing member comprises ceramic.

100. The intervertebral spacing implant of claim 139, wherein the spacing member includes an anterior wall and a posterior wall, and wherein the external concavo-convex contour of the spacer is defined by the posterior wall being concave in a horizontal dimension and by the anterior wall being convex in a horizontal dimension.

101. The intervertebral spacing implant of claim 146, wherein the anterior wall and the posterior wall of the spacing member are each linear in a vertical dimension.

102. The intervertebral spacing implant of claim 147, wherein the concavo-convex contour comprises a concave posterior side, and a convex anterior side disposed in a substantially parallel orientation with respect to the concave posterior side.

2. The intervertebral spacing implant of claim 47, wherein the spacing member comprises metal.

4. The intervertebral spacing implant of claim 47, wherein the spacing member comprises ceramic.

5. The intervertebral spacing implant of claim 47, wherein the spacing member includes an anterior wall and a posterior wall, and wherein the external concavo-convex contour of the spacer is defined by the posterior wall being concave in a horizontal dimension and by the anterior wall being convex in a horizontal dimension.

8. The intervertebral spacing implant of claim 47, wherein the imaginary arcuate centerline enables said spacing member to be inserted through an incision along an arcuate insertion path.

9. The intervertebral spacing implant of claim 54, wherein the spacing member is configured and adapted to be inserted along said arcuate insertion path in a manner such that said arcuate insertion path coincides with the imaginary arcuate centerline of said spacing member.

10. The intervertebral spacing implant of claim 47, wherein the spacing member further comprises a disc-like member having a thickness at a thickest part of the spacing member, and a length that is greater in length than said thickness at said thickest part, and a width that is greater in width than said thickness at said thickest part.

12. The intervertebral spacing implant of claim 47, wherein the spacing member further comprises an upper side having a plurality of spaced-apart recesses formed therein.

13. The intervertebral spacing implant of claim 58, wherein the recesses are elongate and are disposed in a substantially parallel orientation with respect to each other.

14. The intervertebral spacing implant of claim 59, wherein the recesses extend in an anterior-to-posterior direction.

15. The intervertebral spacing implant of claim 47, said spacing member having a discontinuous upper surface.

16. The intervertebral spacing implant of claim 47, wherein said spacing member comprises a tapered external shape such that said spacing member narrows in thickness in a first direction.

17. The intervertebral spacing implant of claim 62, wherein the tapered external shape of said spacing member narrows in thickness in a continuous manner along a majority width of said spacing member in an anterior-to-posterior direction.

18. The intervertebral spacing implant of claim 63, wherein the spacing member includes an upper surface that forms a first acute angle with respect to a horizontal plane, said first acute angle being in a range of two to six degrees.

19. The intervertebral spacing implant of claim 63, the spacing member having a discontinuous upper surface.

20. The intervertebral spacing implant of claim 65, wherein the upper surface includes a plurality of elongate recesses formed therein, said recesses extending in an anterior-to-posterior direction.

21. The intervertebral spacing implant of claim 64, wherein the spacing member includes a lower surface that forms a second acute angle with respect to a horizontal plane, said second acute angle being in a range of approximately two degrees to eight degrees.

23. The intervertebral spacing implant of claim 62, wherein said spacing member further comprises a convex side, and wherein the tapered external shape of said spacing member is adapted such that said spacing member narrows in thickness in an anterior-to-posterior direction when implanted with said convex side facing an anterior direction.

24. The intervertebral spacing implant of claim 69, wherein the spacing member further comprises an upper surface, and wherein the tapered external shape of the spacing member is such that the upper surface of said spacing member defines a first acute angle with respect to a plane that is orthogonal to the convex side of the spacing member.

25. The intervertebral spacing implant of claim 62, wherein the tapered external shape of said spacing member comprises a taper sufficient in degree to permit a lordosis spinal configuration to be restored when said spacing member is sandwiched between adjacent intervertebral bodies.

26. The intervertebral spacing implant of claim 47, wherein the spacing member includes an upper surface and a lower surface, and wherein said upper surface and said lower surface are substantially parallel.

27. The intervertebral spacing implant of claim 47, wherein the imaginary arcuate centerline extends between opposing free ends, said spacing member tapering in thickness in a direction toward one of said free ends such that the thickness at one end is greater than the thickness at the other end.

28. The intervertebral spacing implant of claim 47, wherein said spacing member further comprising an upper surface and a lower surface, wherein at least one of said surfaces is multi-planar including at least two nonparallel planes.

29. The intervertebral spacing implant of claim 47, wherein said spacing member further comprises an upper side having a plurality of spaced-apart ridges and valleys formed therein, wherein the ridges and valleys extend in an anterior-to-posterior direction.

30. The intervertebral spacing implant of claim 47, wherein said spacing member further comprises attachment means for releasably attaching positioning means to said spacing member.

31. The intervertebral spacing implant of claim 76, wherein said attachment means for releasably attaching positioning means to said spacing member comprises a recess in said spacing member.

32. The intervertebral spacing implant of claim 77, wherein said attachment means for releasably attaching positioning means to said spacing member comprises a threaded bore.

33. The intervertebral spacing implant of claim 47, wherein said implant is made of bone.

34. The intervertebral spacing implant of claim 47, wherein said implant is inert.

36. The intervertebral spacing implant of claim 81, wherein the spacing member comprises metal.

38. The intervertebral spacing implant of claim 81, wherein the spacing member comprises ceramic.

39. The intervertebral spacing implant of claim 81, wherein the spacing member defines an imaginary arcuate centerline residing between opposing sides of the external concavo-convex contour of said spacing member, said arcuate centerline forming less than half a circle.

40. The intervertebral spacing implant of claim 81, wherein the spacing member further comprises an upper side having a plurality of spaced-apart ridges and valleys formed therein.

43. The intervertebral spacing implant of claim 81, wherein the spacing member includes an upper surface and a lower surface, and wherein said upper surface and said lower surface are substantially parallel.

44. The intervertebral spacing implant of claim 81, wherein the spacing member defines an imaginary arcuate centerline extending between opposing free ends, said spacing member tapering in thickness in a direction toward one of said free ends such that the thickness at one end is greater than the thickness at the other end.

45. The intervertebral spacing implant of claim 81, wherein said spacing member further comprises an upper surface and a lower surface, wherein at least one of said surfaces is multi-planar including at least two nonparallel planes.

46. The intervertebral spacing implant of claim 81, wherein said spacing member further comprises attachment means for releasably attaching positioning means to said spacing member.

47. The intervertebral spacing implant of claim 92, wherein said attachment means for releasably attaching positioning means to said spacing member comprises a recess in said spacing member.

49. The intervertebral spacing implant of claim 81, wherein said spacing member comprises a tapered external shape such that said spacing member narrows in thickness in an anterior-to-posterior direction.

50. The intervertebral spacing implant of claim 81, wherein the spacing member includes an upper surface that forms a first acute angle with respect to a horizontal plane, said first acute angle being in a range of two to six degrees.

53. The intervertebral spacing implant of claim 81, wherein the thickest part of the spacing member is at the anterior wall corresponding to the convex contour.

54. The intervertebral spacing implant of claim 81, wherein said implant is made of bone.

55. The intervertebral spacing implant of claim 81, wherein said implant is inert.

57. The intervertebral spacing implant of claim 102, wherein the spacing member is either inherently non-porous or is otherwise rendered non-porous.

58. The intervertebral spacing implant of claim 102, wherein the spacing member is constructed from a rigid, non-resilient load-bearing material.

59. The intervertebral spacing implant of claim 102, wherein the arcuate centerline forms less than half a circle.

60. The intervertebral spacing implant of claim 102, wherein the spacing member comprises metal.

62. The intervertebral spacing implant of claim 102, wherein the spacing member is porous.

63. The intervertebral spacing implant of claim 102, wherein the spacing member includes an upper surface and a lower surface, and wherein said upper surface and said lower surface are substantially parallel.

64. The intervertebral spacing implant of claim 102, wherein said spacing member further comprising an upper surface and a lower surface, wherein at least one of said surfaces is multi-planar including at least two nonparallel planes.

65. The intervertebral spacing implant of claim 102, wherein said spacing member further comprises an upper side having a plurality of spaced-apart ridges and valleys formed therein, wherein the ridges and valleys extend in an anterior-to-posterior direction.

66. The intervertebral spacing implant of claim 102, wherein said spacing member further comprises attachment means for releasably attaching positioning means to said spacing member.

69. The intervertebral spacing implant of claim 102, wherein the spacing member comprises ceramic.

70. The intervertebral spacing implant of claim 102, wherein the spacing member includes an anterior wall and a posterior wall, and wherein the external concavo-convex contour of the spacer is defined by the posterior wall being concave in a horizontal dimension and by the anterior wall being convex in a horizontal dimension.

73. The intervertebral spacing implant of claim 102, wherein the imaginary arcuate centerline enables said spacing member to be inserted through an incision along an arcuate insertion path.

75. The intervertebral spacing implant of claim 102, wherein the spacing member further comprises a disc-like member having a thickness at a thickest part of said spacing member, and a length that is greater in length than said thickness at said thickest part, and a width that is greater in width than said thickness at said thickest part.

76. The intervertebral spacing implant of claim 102, wherein the thickness of the spacing member is defined by a perimeter wall that constitutes the concave side and the convex side of the external concavo-convex contour of said spacing member.

77. The intervertebral spacing implant of claim 102, wherein the spacing member further comprises an upper side having a plurality of spaced-apart recesses formed therein.

80. The intervertebral spacing implant of claim 102, said spacing member having a discontinuous upper surface.

81. The intervertebral spacing implant of claim 102, wherein said spacing member comprises a tapered external shape such that said spacing member narrows in thickness in a first direction.

91. The intervertebral spacing implant of claim 102, wherein said implant is made of bone.

92. The intervertebral spacing implant of claim 102, wherein said implant is inert.

103. The intervertebral spacing implant of claim 142, wherein the imaginary arcuate centerline enables said spacing member to be inserted through an incision along an arcuate insertion path.

104. The intervertebral spacing implant of claim 149, wherein the spacing member is configured and adapted to be inserted along said arcuate insertion path in a manner such that said arcuate insertion path coincides with the imaginary arcuate centerline of said spacing member.

105. The intervertebral spacing implant of claim 139, wherein the spacing member further comprises a disc-like member having a thickness at a thickest part of said spacing member, and a length that is greater in length than said thickness at said thickest part, and a width that is greater in width than said thickness at said thickest part.

106. The intervertebral spacing implant of claim 151, wherein the thickness of the spacing member is defined by a perimeter wall that constitutes the concave side and the convex side of the external concavo-convex contour of said spacing member.

61. The intervertebral spacing implant of claim 106, wherein the spacing member comprises titanium.

107. The intervertebral spacing implant of claim 139, wherein said upper surface comprises a plurality of spaced-apart recesses formed therein.

108. The intervertebral spacing implant of claim 153, wherein the recesses are elongate and are disposed in a substantially parallel orientation with respect to each other.

109. The intervertebral spacing implant of claim 154, wherein the recesses extend in an anterior-to-posterior direction.

110. The intervertebral spacing implant of claim 139, wherein said upper surface is discontinuous.

111. The intervertebral spacing implant of claim 139, wherein said spacing member comprises a tapered external shape such that said spacing member narrows in thickness in a first direction.

112. The intervertebral spacing implant of claim 157, wherein the tapered external shape of said spacing member narrows in thickness in a continuous manner along a majority width of said spacing member in an anterior-to-posterior direction.

22. The intervertebral spacing implant of claim 67, wherein the first acute angle and the second acute angle are approximately four degrees with respect to a horizontal plane, for a total continuous taper of approximately eight degrees.

67. The intervertebral spacing implant of claim 112, wherein said attachment means for releasably attaching positioning means to said spacing member comprises a recess in said spacing member.

113. The intervertebral spacing implant of claim 158, wherein said upper surface forms a first acute angle with respect to a horizontal plane, said first acute angle being in a range of two to six degrees.

68. The intervertebral spacing implant of claim 113, wherein said attachment means for releasably attaching positioning means to said spacing member comprises a threaded bore.

114. The intervertebral spacing implant of claim 159, wherein said lower surface forms a second acute angle with respect to a horizontal plane, said second acute angle being in a range of approximately two degrees to eight degrees.

115. The intervertebral spacing implant of claim 160, wherein the first and second acute angles each form a continuous acute angle of approximately four degrees with respect to a horizontal plane, for a total continuous taper of approximately eight degrees.

116. The intervertebral spacing implant of claim 157, wherein said spacing member further comprises a convex side, and wherein the tapered external shape of said spacing member is adapted such that said spacing member narrows in thickness in an anterior-to-posterior direction when implanted with said convex side facing an anterior direction.

71. The intervertebral spacing implant of claim 116, wherein the anterior wall and the posterior wall of the spacing member are each linear in a vertical dimension.

117. The intervertebral spacing implant of claim 162, wherein the tapered external shape of the spacing member is such that the upper surface of said spacing member defines a first acute angle with respect to a plane that is orthogonal to the convex side of the spacing member.

72. The intervertebral spacing implant of claim 117, wherein the concavo-convex contour comprises a concave posterior side, and a convex anterior side disposed in a substantially parallel orientation with respect to the concave posterior side.

118. The intervertebral spacing implant of claim 157, wherein the tapered external shape of said spacing member comprises a taper sufficient in degree to permit a lordosis spinal configuration to be restored when said spacing member is sandwiched between adjacent intervertebral bodies.

119. The intervertebral spacing implant of claim 139, wherein said upper surface and said lower surface are substantially parallel.

74. The intervertebral spacing implant of claim 119, wherein the spacing member is configured and adapted to be inserted along said arcuate insertion path in a manner such that said arcuate insertion path coincides with the imaginary arcuate centerline of said spacing member.

120. The intervertebral spacing implant of claim 139, wherein the spacing member defines an imaginary arcuate centerline extending between opposing free ends, said spacing member tapering in thickness in a direction toward one of said free ends such that the thickness at one end is greater than the thickness at the other end.

121. The intervertebral spacing implant of claim 139, wherein said upper surface comprises a plurality of spaced-apart ridges and valleys formed therein, wherein the ridges and valleys extend in an anterior-to-posterior direction.

122. The intervertebral spacing implant of claim 139, wherein said spacing member further comprises attachment means for releasably attaching positioning means to said spacing member.

123. The intervertebral spacing implant of claim 168, wherein said attachment means for releasably attaching positioning means to said spacing member comprises a recess in said spacing member.

78. The intervertebral spacing implant of claim 123, wherein the recesses are elongate and are disposed in a substantially parallel orientation with respect to each other.

124. The intervertebral spacing implant of claim 169, wherein said attachment means for releasably attaching positioning means to said spacing member comprises a threaded bore.

79. The intervertebral spacing implant of claim 124, wherein the recesses extend in an anterior-to-posterior direction.

125. The intervertebral spacing implant of claim 139, wherein said spacing member is porous.

126. The intervertebral spacing implant of claim 139, wherein said implant is made of bone.

127. The intervertebral spacing implant of claim 139, wherein said implant is inert.

37. The intervertebral spacing implant of claim 82, wherein the spacing member comprises titanium.

82. The intervertebral spacing implant of claim 127, wherein the tapered external shape of said spacing member narrows in thickness in a continuous manner along a majority width of said spacing member in an anterior-to-posterior direction.

88. The intervertebral spacing implant of claim 127, wherein said spacing member further comprises a convex side, and wherein the tapered external shape of said spacing member is adapted such that said spacing member narrows in thickness in an anterior-to-posterior direction when implanted with said convex side facing an anterior direction.

90. The intervertebral spacing implant of claim 127, wherein the tapered external shape of said spacing member comprises a taper sufficient in degree to permit a lordosis spinal configuration to be restored when said spacing member is sandwiched between adjacent intervertebral bodies.

128. An intervertebral spacing implant comprising:

a spacing member adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc, said spacing member further comprising an external, concavo-convex contour with respect to one dimension of said spacing member;

wherein the spacing member is constructed from a rigid, non-resilient load-bearing material;

wherein said spacing member further comprises an upper side having a plurality of spaced-apart ridges and valleys formed therein;

wherein the ridges and valleys are elongate and wherein all said ridges and valleys are disposed in an orientation consisting only of a parallel orientation with respect to each other; and

wherein the ridges and valleys extend in an anterior-to-posterior direction.

83. The intervertebral spacing implant of claim 128, wherein the spacing member includes an upper surface that forms a first acute angle with respect to a horizontal plane, said first acute angle being in a range of two to six degrees.

84. The intervertebral spacing implant of claim 128, the spacing member having a discontinuous upper surface.

129. The intervertebral spacing implant of claim 174, wherein said implant is made of bone.

41. The intervertebral spacing implant of claim 86, wherein the ridges and valleys are disposed in a substantially parallel orientation with respect to each other.

86. The intervertebral spacing implant of claim 129, wherein the spacing member includes a lower surface that forms a second acute angle with respect to a horizontal plane, said second acute angle being in a range of approximately two degrees to eight degrees.

130. The intervertebral spacing implant of claim 174, wherein said implant is inert.

85. The intervertebral spacing implant of claim 130, wherein the upper surface includes a plurality of elongate recesses formed therein, said recesses extending in an anterior-to-posterior direction.

131. An intervertebral spacing implant comprising:

a spacing member adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc, said spacing member further comprising an external, concavo-convex contour with respect to one dimension of said spacing member;

wherein the spacing member is either inherently non-porous or is otherwise rendered non-porous;

wherein the spacing member is constructed from a rigid, non-resilient load-bearing material;

wherein said spacing member further comprises an upper side having a plurality of spaced-apart ridges and valleys formed therein;

wherein the ridges and valleys are elongate and are disposed in a substantially parallel orientation with respect to each other; and

wherein the ridges and valleys extend in an anterior-to-posterior direction.

132. An intervertebral spacing implant comprising:

a spacing member adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc, said spacing member further comprising an external, concavo-convex contour with respect to one dimension of said spacing member;

wherein the spacing member is constructed from a rigid, non-resilient load-bearing bone material; and

wherein the spacing member defines an imaginary concavo-convex centerline residing between opposing sides of the external concavo-convex contour of said spacing member, said concavo-convex centerline forming less than half a circle or otherwise forming an angle that is greater than ninety degrees and less than 180 degrees.

42. The intervertebral spacing implant of claim 87, wherein the ridges and valleys extend in an anterior-to-posterior direction.

87. The intervertebral spacing implant of claim 132, wherein the first acute angle and the second acute angle each form a continuous acute angle of approximately four degrees with respect to a horizontal plane, for a total continuous taper of approximately eight degrees.

133. An intervertebral spacing implant comprising:

a spacing member adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc, said spacing member further comprising an external, concavo-convex contour with respect to one dimension of said spacing member;

wherein the spacing member is either inherently non-porous or is otherwise rendered non-porous, and is constructed from a rigid, non-resilient load-bearing material; and

wherein the spacing member defines an imaginary concavo-convex centerline residing between opposing sides of the external concavo-convex contour of said spacing member, said concavo-convex centerline forming less than half a circle or otherwise forming an angle that is greater than ninety degrees and less than 180 degrees.