Biodegradable/bioactive nucleus pulposus implant and method for treating degenerated intervertebral discs

• US 20030033017A1
• Filed: 05/24/2002
• Published: 02/13/2003
• Est. Priority Date: 06/29/2001
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Bradford, David S., Lotz, Jeffrey C., Colliou, Olivier K.
• Granted Patent: US 7,156,877 B2
• Time in Patent Office: Days
• US Class Current: 623/17.16
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• 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 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30069 elastomeric
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/444 for replacing the nucleus pulposus
• 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 2002/4629 connected to the endoprosthesis or implant via a threaded connection
• CPC Class Codes: A61F 2002/4635 using minimally invasive surgery
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2230/0015 Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2310/00365 Proteins; Polypeptides; Degradation products thereof
• CPC Class Codes: A61F 2310/0097 Coating or prosthesis-covering structure made of pharmaceutical products, e.g. antibiotics
• CPC Class Codes: A61L 2430/38 for reconstruction of the spine, vertebrae or intervertebral discs
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/58 Materials at least partially resorbable by the body
• CPC Class Codes: B29C 41/14 Dipping a core B29C41/10 takes precedence
• CPC Class Codes: B29C 41/42 : Removing articles from moulds, cores or other substrates B29C33/444 and B29C37/0017 take precedence
• CPC Class Codes: C08L 71/02 : Polyalkylene oxides
• CPC Class Codes: C08L 75/04 : Polyurethanes

Abstract

A bioactive/biodegradable nucleus implant for repairing degenerated intervertebral discs that is inflated inside the nucleus space after the degenerated nucleus has been removed to re-pressurize the nuclear space within the intervertebral disc. The implant is inflated with a high molecular weight fluid, gel or combination of fluid and elastomer, preferably an under-hydrated HA hydrogel/growth factor mixture with or without host cells. The implant includes an internal, integral, self-sealing valve that allows one-way filling of the implant after it is placed within the disc, and is made from a material that allows fibrous in growth thereby stabilizing the implant. A variety of substances can be incorporated into the implant to promote healing, prevent infection, or arrest pain.

Claims

1. An implant for repairing an intervertebral disc, comprising:

an inflatable membrane;

said membrane having an internal chamber;

said membrane having an integral, internal self-sealing fill valve.

2. An implant as recited in claim 1, wherein said membrane comprises an elastomer.

3. An implant as recited in claim 2, wherein said elastomer is biodegradable.

4. An implant as recited in claim 2, wherein said elastomer comprises polyurethane.

5. An implant as recited in claim 4, wherein said polyurethane comprises aliphatic polycarbonate polyurethane.

6. An implant as recited in claim 1, wherein said chamber is filled with a hydrogel.

7. An implant as recited in claim 6, wherein said hydrogel comprises cross-linkable polyethylene glycol.

8. An implant as recited in claim 6, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

9. An implant as recited in claim 6, wherein said hydrogel comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

10. An implant as recited in claim 9, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

11. An implant for repairing an intervertebral disc, comprising:

an inflatable membrane;

said membrane having an internal chamber; and

means for sealing a fill material within said chamber.

12. An implant as recited in claim 11, wherein said means comprises an internal, self-sealing, fill-valve integral to said membrane.

13. An implant as recited in claim 11, wherein said membrane comprises an elastomer.

14. An implant as recited in claim 13, wherein said elastomer is biodegradable.

15. An implant as recited in claim 13, wherein said elastomer comprises polyurethane.

16. An implant as recited in claim 15, wherein said polyurethane comprises aliphatic polycarbonate polyurethane.

17. An implant as recited in claim 11, wherein said chamber is filled with a hydrogel.

18. An implant as recited in claim 17, wherein said hydrogel comprises cross-linkable polyethylene glycol.

19. An implant as recited in claim 17, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

20. An implant as recited in claim 17, wherein said hydrogel comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

21. An implant as recited in claim 20, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

22. An implant for repairing an intervertebral disc, comprising:

an inflatable, elastic membrane;

said membrane having an internal chamber;

said membrane having an integral, internal self-sealing fill valve.

23. An implant as recited in claim 22, wherein said membrane is biodegradable.

25. An implant as recited in claim 22, wherein said membrane comprises polyurethane.

26. An implant as recited in claim 25, wherein said polyurethane comprises aliphatic polycarbonate polyurethane.

27. An implant as recited in claim 22, wherein said chamber is filled with a hydrogel.

28. An implant as recited in claim 27, wherein said hydrogel comprises cross-linkable polyethylene glycol.

29. An implant as recited in claim 27, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

30. An implant as recited in claim 27, wherein said hydrogel comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

31. An implant as recited in claim 30, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

32. An implant for repairing an intervertebral disc, comprising:

an inflatable, biodegradable, aliphatic polycarbonate polyurethane membrane;

said membrane having an internal chamber;

said membrane having an integral, internal self-sealing fill valve.

33. An implant as recited in claim 32, wherein said chamber is filled with a hydrogel.

34. An implant as recited in claim 33, wherein said hydrogel comprises cross-linkable polyethylene glycol.

35. An implant as recited in claim 33, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

36. An implant as recited in claim 33, wherein said hydrogel comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

37. An implant as recited in claim 36, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

38. An implant for repairing an intervertebral disc, comprising:

an inflatable, biodegradable, aliphatic polycarbonate polyurethane membrane;

said membrane having an internal chamber filled with a hydrogel;

said membrane having an integral, internal self-sealing fill valve.

39. An implant as recited in claim 38, wherein said hydrogel comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

40. An implant as recited in claim 39, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

41. An implant for repairing an intervertebral disc, comprising:

an inflatable, biodegradable, aliphatic polycarbonate polyurethane membrane;

said membrane having an internal chamber filled with a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa) and a “

2-arm”

amine-specific electrophilic dimer;

said membrane having an integral, internal self-sealing fill valve.

42. An implant as recited in claim 41, wherein said material in said chamber is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

43. A method for repairing an intervertebral disc, comprising:

inserting an inflatable implant into a nuclear space within an intervertebral disk; and

inflating said implant with a hydrogel.

44. A method as recited in claim 43, wherein said implant comprises:

an inflatable membrane;

said membrane having an internal chamber;

said membrane having an integral, internal self-sealing fill valve.

45. A method as recited in claim 44, wherein said membrane comprises an elastomer.

46. A method as recited in claim 45, wherein said elastomer is biodegradable.

47. A method as recited in claim 45, wherein said elastomer comprises polyurethane.

48. A method as recited in claim 47, wherein said polyurethane comprises aliphatic polycarbonate polyurethane.

49. A method as recited in claim 43, wherein said hydrogel comprises cross-linkable polyethylene glycol.

50. A method as recited in claim 43, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

51. A method as recited in claim 43, wherein said hydrogel comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

52. A method as recited in claim 51, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

53. A method as recited in claim 43, further comprising removing nucleus pulposus tissue to form said nuclear space.

54. A method as recited in claim 53, further comprising removing said nucleus pulposus tissue by performing a postero-lateral percutaneous discectomy.

55. A method for repairing an intervertebral disc, comprising:

inserting an inflatable implant into a nuclear space within an intervertebral disk;

wherein said inflatable implant comprises,

an inflatable membrane,

said membrane having an internal chamber,

said membrane having an integral, internal self-sealing fill valve; and

inflating said implant with a hydrogel.

56. A method as recited in claim 55, wherein said membrane comprises an elastomer.

57. A method as recited in claim 56, wherein said elastomer is biodegradable.

58. A method as recited in claim 56, wherein said elastomer comprises polyurethane.

59. A method as recited in claim 58, wherein said polyurethane comprises aliphatic polycarbonate polyurethane.

60. A method as recited in claim 55, wherein said hydrogel comprises cross-linkable polyethylene glycol.

61. A method as recited in claim 55, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

62. A method as recited in claim 55, wherein said hydrogel comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

63. A method as recited in claim 62, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

64. A method as recited in claim 55, further comprising removing nucleus pulposus tissue to form said nuclear space.

65. A method as recited in claim 64, further comprising removing said nucleus pulposus tissue by performing a postero-lateral percutaneous discectomy.

66. A method for repairing an intervertebral disc, comprising:

inserting an inflatable implant into a nuclear space within an intervertebral disc; and

inflating said implant with cross-linkable polyethylene glycol.

67. A method as recited in claim 66, wherein said cross-linkable polyethylene glycol is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

68. A method as recited in claim 66, wherein said cross-linkable polyethylene glycol comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

69. A method as recited in claim 66, wherein said implant comprises:

an inflatable membrane;

said membrane having an internal chamber;

said membrane having an integral, internal self-sealing fill valve.

70. A method as recited in claim 69, wherein said membrane comprises an elastomer.

71. A method as recited in claim 70, wherein said elastomer is biodegradable.

72. A method as recited in claim 70, wherein said elastomer comprises polyurethane.

73. A method as recited in claim 72, wherein said polyurethane comprises aliphatic polycarbonate polyurethane.

74. A method as recited in claim 66, further comprising removing nucleus pulposus tissue to form said nuclear space.

75. A method as recited in claim 74, further comprising removing said nucleus pulposus tissue by performing a postero-lateral percutaneous discectomy.

76. A method for repairing an intervertebral disc, comprising:

inserting an inflatable implant into a nuclear space within an intervertebral disc;

wherein said inflatable implant comprises,

an inflatable membrane,

said membrane having an internal chamber,

said membrane having an integral, internal self-sealing fill valve; and

inflating said implant with cross-linkable polyethylene glycol.

77. A method as recited in claim 76, wherein said cross-linkable polyethylene glycol is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

78. A method as recited in claim 76, wherein said cross-linkable polyethylene glycol comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

79. A method as recited in claim 76, wherein said membrane comprises an elastomer.

80. A method as recited in claim 79, wherein said elastomer is biodegradable.

81. A method as recited in claim 79, wherein said elastomer comprises polyurethane.

82. A method as recited in claim 81, wherein said polyurethane comprises aliphatic polycarbonate polyurethane.

83. A method as recited in claim 76, further comprising removing nucleus pulposus tissue to form said nuclear space.

84. A method as recited in claim 83, further comprising removing said nucleus pulposus tissue by performing a postero-lateral percutaneous discectomy.

85. A method for repairing an intervertebral disc, comprising:

inserting an inflatable implant into a nuclear space within an intervertebral disc;

wherein said inflatable implant comprises,

an inflatable, aliphatic polycarbonate polyurethane membrane,

said membrane having an internal chamber,

said membrane having an integral, internal self-sealing fill valve; and

inflating said implant with a mixture of cross-linkable polyethylene glycol and an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

86. A method as recited in claim 85, wherein said cross-linkable polyethylene glycol comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

87. A method as recited in claim 85, further comprising removing nucleus pulposus tissue to form said nuclear space.

88. A method as recited in claim 87, further comprising removing said nucleus pulposus tissue by performing a postero-lateral percutaneous discectomy.

89. An implant system for repairing an intervertebral disc, comprising:

an inflatable membrane;

said membrane having an internal chamber;

said membrane having an integral, internal self-sealing fill valve;

said membrane configured for insertion into a nuclear space created by removing nucleus pulposus tissue in an intervertebral disc; and

an annular buttress configured for placement in the annulus fibrosus of said intervertebral disc and retention of said membrane in said nuclear space.

90. An implant system as recited in claim 89, wherein said buttress includes a plurality of pins configured for engaging said annulus fibrosus.

91. An implant system as recited in claim 89, wherein said membrane comprises an elastomer.

92. An implant system as recited in claim 91, wherein said elastomer is biodegradable.

93. An implant system as recited in claim 91, wherein said elastomer comprises polyurethane.

94. An implant system as recited in claim 93, wherein said polyurethane comprises aliphatic polycarbonate polyurethane.

95. An implant system as recited in claim 89, wherein said chamber is filled with a hydrogel.

96. An implant system as recited in claim 95, wherein said hydrogel comprises cross-linkable polyethylene glycol.

97. An implant system as recited in claim 95, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

98. An implant system as recited in claim 95, wherein said hydrogel comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

99. An implant system as recited in claim 98, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

100. An implant system for repairing an intervertebral-disc, comprising:

an inflatable membrane;

said membrane having an internal chamber;

means for sealing a fill material within said chamber;

said membrane configured for insertion into a nuclear space created by removing nucleus pulposus tissue in an intervertebral disc; and

an annular buttress configured for placement in the annulus fibrosus of said intervertebral disc and retention of said membrane in said nuclear space.

101. An implant system as recited in claim 100, wherein said buttress includes a plurality of pins configured for engaging said annulus fibrosus.

102. An implant system as recited in claim 100, wherein said means comprises an internal, self-sealing, fill-valve integral to said membrane.

103. An implant system as recited in claim 100, wherein said membrane comprises an elastomer.

104. An implant system as recited in claim 103, wherein said elastomer is biodegradable.

105. An implant system as recited in claim 103, wherein said elastomer comprises polyurethane.

106. An implant system as recited in claim 105, wherein said polyurethane comprises aliphatic polycarbonate polyurethane.

107. An implant system as recited in claim 100, wherein said chamber is filled with a hydrogel.

108. An implant system as recited in claim 107, wherein said hydrogel comprises cross-linkable polyethylene glycol.

109. An implant system as recited in claim 107, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

110. An implant system as recited in claim 107, wherein said hydrogel comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

111. An implant system as recited in claim 110, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

112. An implant system for repairing an intervertebral disc, comprising:

an inflatable, elastic membrane;

said membrane having an internal chamber;

said membrane having an integral, internal self-sealing fill valve;

said membrane configured for insertion into a nuclear space created by removing nucleus pulposus tissue in an intervertebral disc; and

an annular buttress configured for placement in the annulus fibrosus of said intervertebral disc and retention of said membrane in said nuclear space.

113. An implant system as recited in claim 112, wherein said buttress includes a plurality of pins configured for engaging said annulus fibrosus.

114. An implant system as recited in claim 112, wherein said membrane is biodegradable.

115. An implant system as recited in claim 112, wherein said membrane comprises polyurethane.

116. An implant system as recited in claim 115, wherein said polyurethane comprises aliphatic polycarbonate polyurethane.

117. An implant system as recited in claim 112, wherein said chamber is filled with a hydrogel.

118. An implant system as recited in claim 117, wherein said hydrogel comprises cross-linkable polyethylene glycol.

119. An implant system as recited in claim 117, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

120. An implant system as recited in claim 117, wherein said hydrogel comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

121. An implant system as recited in claim 120, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

122. An implant system for repairing an intervertebral disc, comprising:

an inflatable, biodegradable, aliphatic polycarbonate polyurethane membrane;

said membrane having an internal chamber;

said membrane having an integral, internal self-sealing fill valve;

said membrane configured for insertion into a nuclear space created by removing nucleus pulposus tissue in an intervertebral disc; and

an annular buttress configured for placement in the annulus fibrosus of said intervertebral disc and retention of said membrane in said nuclear space.

123. An implant system as recited in claim 122, wherein said buttress includes a plurality of pins configured for engaging said annulus fibrosus.

124. An implant system as recited in claim 122, wherein said chamber is filled with a hydrogel.

125. An implant system as recited in claim 124, wherein said hydrogel comprises cross-linkable polyethylene glycol.

126. An implant system as recited in claim 124, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

127. An implant system as recited in claim 124, wherein said hydrogel comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

128. An implant system as recited in claim 127, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

129. An implant system for repairing an intervertebral disc, comprising:

an inflatable, biodegradable, aliphatic polycarbonate polyurethane membrane;

said membrane having an internal chamber filled with a hydrogel;

said membrane having an integral, internal self-sealing fill valve;

said membrane configured for insertion into a nuclear space created by removing nucleus pulposus tissue in an intervertebral disc; and

an annular buttress configured for placement in the annulus fibrosus of said intervertebral disc and retention of said membrane in said nuclear space.

130. An implant system as recited in claim 129, wherein said buttress includes a plurality of pins configured for engaging said annulus fibrosus.

131. An implant system as recited in claim 129, wherein said hydrogel comprises:

a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa); and

a “

2-arm”

amine-specific electrophilic dimer.

132. An implant system as recited in claim 131, wherein said hydrogel is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

133. An implant system for repairing an intervertebral disc, comprising:

an inflatable, biodegradable, aliphatic polycarbonate polyurethane membrane;

said membrane having an internal chamber filled with a nucleophilic “

8-arm”

octomer (PEG-NH₂, MW 20 kDa) and a “

2-arm”

amine-specific electrophilic dimer;

said membrane having an integral, internal self-sealing fill valve;

said membrane configured for insertion into a nuclear space created by removing nucleus pulposus tissue in an intervertebral disc; and

an annular buttress configured for placement in the annulus fibrosus of said intervertebral disc and retention of said membrane in said nuclear space.

134. An implant system as recited in claim 133, wherein said buttress includes a plurality of pins configured for engaging said annulus fibrosus.

135. An implant system as recited in claim 133, wherein said material in said chamber is mixed with an additive selected from the group consisting essentially of chondroitin sulfate and hyaluronic acid.

136. An apparatus for sealing a nuclear space after removal of nucleus pulposus tissue in a intervertebral disc, comprising:

an annular buttress;

said buttress configured for placement in the annulus fibrosus of said intervertebral disc;

said buttress including a plurality of pins configured for engaging said annulus fibrosus.

137. An apparatus as recited in claim 136, wherein said buttress comprises:

an annular head portion; and

a body portion extending from said head portion;

said pins extending from said head portion and along said body portion.

138. An apparatus as recited in claim 137, further comprising an opening extending through said head portion and said body portion.

139. An apparatus as recited in claim 138, further comprising threads in at least a portion of said opening.

140. An apparatus as recited in claim 137, wherein said pins have ends extending outward in relation to said body portion.

141. An apparatus as recited in claim 140, wherein said body portion has a diameter smaller than the diameter of said head portion.

142. An apparatus for sealing a nuclear space after removal of nucleus pulposus tissue in a intervertebral disc, comprising:

an annular buttress;

said buttress configured for placement in the annulus fibrosus of said intervertebral disc; and

means for engaging coupling said buttress to said annulus fibrosus.

143. An apparatus as recited in claim 142, wherein said means comprises a plurality of pins attached to said buttress.

144. An apparatus as recited in claim 143, wherein said buttress comprises:

an annular head portion; and

a body portion extending from said head portion;

said pins extending from said head portion and along said body portion.

145. An apparatus as recited in claim 144, further comprising an opening extending through said head portion and said body portion.

146. An apparatus as recited in claim 145, further comprising threads in at least a portion of said opening.

147. An apparatus as recited in claim 144, wherein said pins having ends extending outward in relation to said body portion.

148. An apparatus as recited in claim 147, wherein said body portion has a diameter smaller than the diameter of said head portion.

149. An apparatus for sealing a nuclear space after removal of nucleus pulposus tissue in a intervertebral disc, comprising:

an annular buttress;

said buttress having a head portion;

said buttress having a body portion extending from said head portion; and

a plurality of pins extending from said head portion and along said body portion.

150. An apparatus as recited in claim 149, further comprising an opening extending through said head portion and said body portion.

151. An apparatus as recited in claim 150, further comprising threads in at least a portion of said opening.

152. An apparatus as recited in claim 149, wherein said pins have ends extending outward in relation to said body portion.

153. An apparatus as recited in claim 152, wherein said body portion has a diameter smaller than the diameter of said head portion.

154. An apparatus for sealing a nuclear space after removal of nucleus pulposus tissue in a intervertebral disc, comprising:

an annular buttress;

said buttress having a head portion;

said buttress having a body portion extending from said head portion;

said body portion having a diameter smaller than the diameter of said head portion; and

a plurality of pins extending from said head portion and along said body portion;

said pins having ends extending outward in relation to said body portion.

155. An apparatus as recited in claim 154, further comprising an opening extending through said head portion and said body portion.

156. An apparatus as recited in claim 155, further comprising threads in at least a portion of said opening.

157. A method of fabricating an implant for repairing an intervertebral disc, comprising:

coating a mandrel with a membrane material;

drying said membrane material;

drawing said membrane material off of said mandrel by rolling said membrane material toward an end of said mandrel; and

sealing an end of said membrane material.

158. A method as recited in claim 157, wherein said mandrel comprises:

a stem portion;

a first cylindrical base portion extending from said stem portion;

a mold portion extending from said first cylindrical base portion;

a second cylindrical base portion extending from said mold portion; and

a shank extending from said second cylindrical base portion.

159. A method as recited in claim 158, further comprising:

dipping said stem portion, said first cylindrical based portion, and said mold portion in a bath of said membrane material to a defined depth.

160. A method as recited in claim 159, wherein said defined depth is generally at a point along said second base portion.

161. A method as recited in claim 157, further comprising molding said membrane to a thickness between approximately 5 mils and 7 mils.

162. A method as recited in claim 158, wherein rolling said membrane off said mandrel turns said membrane inside-out.

163. A method as recited in claim 162, wherein the portion of membrane material that coated said stem portion become a self-sealing valve interior to said implant.

164. A method as recited in claim 162, wherein the portion of said membrane material that coated said first base portion becomes an entrance port into said self-sealing valve.

165. A method of fabricating an implant for repairing an intervertebral disc, comprising:

coating a mandrel with a membrane material to a thickness between approximately 5 mils and approximately 7 mils;

drying said membrane material;

drawing said membrane material off of said mandrel by rolling said membrane is material toward an end of said mandrel; and

sealing an end of said membrane material.

166. A method as recited in claim 165, wherein said mandrel comprises:

a stem portion;

a first cylindrical base portion extending from said stem portion;

a mold portion extending from said first cylindrical base portion;

a second cylindrical base portion extending from said mold portion; and

a shank extending from said second cylindrical base portion.

167. A method as recited in claim 166, further comprising:

dipping said stem portion, said first cylindrical based portion, and said mold portion in a bath of said membrane material to a defined depth.

168. A method as recited in claim 167, wherein said defined depth is generally at a point along said second base portion.

169. A method as recited in claim 166, wherein rolling said membrane off said mandrel turns said membrane inside-out.

170. A method as recited in claim 169, wherein the portion of membrane material that coated said stem portion become a self-sealing valve interior to said implant.

171. A method as recited in claim 169, wherein the portion of said membrane material that coated said first base portion becomes an entrance port into said self-sealing valve.

172. A method of fabricating an implant for repairing an intervertebral disc, comprising:

coating a mandrel with a membrane material to a thickness between approximately 5 mils and approximately 7 mils;

drying said membrane material;

drawing said membrane material off of said mandrel by rolling said membrane material toward an end of said mandrel; and

sealing an end of said membrane material;

wherein said mandrel comprises,

a stem portion,

a first cylindrical base portion extending from said stem portion,

a mold portion extending from said first cylindrical base portion,

a second cylindrical base portion extending from said mold portion, and

a shank extending from said second cylindrical base portion.

173. A method as recited in claim 172, further comprising:

dipping said stem portion, said first cylindrical based portion, and said mold portion in a bath of said membrane material to a defined depth.

174. A method as recited in claim 173, wherein said defined depth is generally at a point along said second base portion.

175. A method as recited in claim 172, wherein rolling said membrane off said mandrel turns said membrane inside-out.

176. A method as recited in claim 175, wherein the portion of membrane material that coated said stem portion become a self-sealing valve interior to said implant.

177. A method as recited in claim 175, wherein the portion of said membrane material that coated said first base portion becomes an entrance port into said self-sealing valve.