Composite intervertebral disc implants and methods for forming the same

• US 20060064172A1
• Filed: 09/23/2004
• Published: 03/23/2006
• Est. Priority Date: 08/30/2000
• Status: Active Grant

• Current Assignee: Hai H. Trieu
• Original Assignee: Hai H. Trieu
• Inventors: Trieu, Hai H.
• Granted Patent: US 7,618,461 B2
• Time in Patent Office: Days
• US Class Current: 623/17.160
• CPC Class Codes: A61B 2017/0256 for the spine
• 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 2002/2817 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 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30179 X-shaped
• CPC Class Codes: A61F 2002/302 toroidal, e.g. rings
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30291 spirally-coiled, i.e. having a 2D spiral cross-section
• CPC Class Codes: A61F 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30594 slotted, e.g. radial or meridian slot ending in a polar aperture, non-polar slots, horizontal or arcuate slots
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30838 Microstructures
• CPC Class Codes: A61F 2002/30891 Plurality of protrusions
• CPC Class Codes: A61F 2002/30906 shot- sand- or grit-blasted
• CPC Class Codes: A61F 2002/30909 : Nets
• CPC Class Codes: A61F 2002/30925 : etched
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/4415 : elements of the prosthesis being arranged in a chain like manner
• CPC Class Codes: A61F 2002/444 : for replacing the nucleus pulposus
• CPC Class Codes: A61F 2002/4495 : having a fabric structure, e.g. made from wires or fibres
• 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 2210/0004 : bioabsorbable
• CPC Class Codes: A61F 2210/0014 : using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2230/0015 : Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2230/0058 : X-shaped
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0091 : helically-coiled or spirally-coiled, i.e. having a 2-D spiral cross-section

Abstract

Nucleus pulposus implants that are resistant to migration in and/or expulsion from an intervertebral disc space are provided. In one form of the invention, an implant includes a load bearing elastic body surrounded in the disc space by an anchoring, preferably resorbable, outer shell. In certain forms of the invention, the elastic body is surrounded by a supporting member, such as a band or jacket, and the supporting member is surrounded by the outer shell. Kits for forming such implants are also provided. In another form of the invention, an implant is provided that has locking features and optional shape memory characteristics. In yet another aspect of the invention, nucleus pulposus implants are provided that have shape memory characteristics and are configured to allow short-term manual, or other deformation without permanent deformation, cracks, tears, breakage or other damage. Methods of forming and implanting the implants are also described.

Claims

1. A method of improving the fit of an intervertebral disc nucleus pulposus implant, said method comprising:

(a) implanting a load bearing elastic body in an intervertebral disc space; and

(b) providing around said elastic body an amount of biocompatible material sufficient to substantially or completely fill the remaining intervertebral disc space around said body.

2. The method of claim 1 wherein said outer shell is provided by injecting a biocompatible material around said elastic body.

3. The method of claim 2 wherein said injected biocompatible material cures into a solid outer shell.

4. The method of claim 3 wherein said solid outer shell is elastic.

5. The method of claim 2 wherein said injected biocompatible material is an adhesive material.

6. The method of claim 5 wherein said biocompatible adhesive material is a resorbable material.

7. The method of claim 5 wherein said biocompatible adhesive material is a non-resorbable material.

8. The method of claim 5 wherein said biocompatible adhesive material is a natural material.

9. The method of claim 5 wherein said biocompatible adhesive material is a synthetic material.

10. The method of claim 5 wherein said biocompatible adhesive material is a curable material.

11. The method of claim 5 wherein said biocompatible adhesive material is a non-curable material.

12. The method of claim 2 wherein said injected biocompatible material is a tissue sealant material.

13. The method of claim 12 wherein said biocompatible tissue sealant material is a resorbable material.

14. The method of claim 12 wherein said biocompatible tissue sealant material is a non-resorbable material.

15. The method of claim 12 wherein said biocompatible tissue sealant material is a natural material.

16. The method of claim 12 wherein said biocompatible tissue sealant material is a synthetic material.

17. The method of claim 12 wherein said biocompatible tissue sealant material is a curable material.

18. The method of claim 12 wherein said biocompatible tissue sealant material is a non-curable material.

19. The method of claim 1 wherein said elastic body fills at least about 50% of the intervertebral disc space.

20. The method of claim 19 wherein said elastic body fills at least about 70% of the intervertebral disc space.

21. The method of claim 20 wherein said elastic body fills at least about 80% of the intervertebral disc space.

22. The method of claim 21 wherein said elastic body fills at least about 90% of the intervertebral disc space.

23. The method of claim 1 wherein said outer shell has a volume of between 1% and 50% of the volume of the composite implant.

24. The method of claim 1 wherein said load bearing elastic body comprises a member selected from the group consisting of elastomeric materials, hydrogels, and hydrophilic polymers, or composites thereof.

25. The method of claim 24 wherein said load bearing elastic body comprises an elastomeric material selected from the group consisting of silicone, polyurethane, copolymers of silicone and polyurethane, polyolefins, and vulcanized rubber.

26. The method of claim 24 wherein said load bearing elastic body comprises a hydrogel comprising one or more materials selected from the group consisting of natural hydrogels, and hydrogels formed from polyvinyl alcohol, acrylamides, polyurethanes, polyethylene glycol, poly(N-vinyl-2-pyrrolidone), acrylates, copolymers of acrylates with N-vinyl pyrrolidone, N-vinyl lactams, acrylamide, polyurethanes and polyacrylonitrile.

27. The method of claim 25 wherein said polyurethane comprises one or more materials selected from the group consisting of thermoplastic polyurethanes, aliphatic polyurethanes, segmented polyurethanes, hydrophilic polyurethanes, polyether-urethanes, polycarbonate-urethanes and silicone polyether-urethanes.

28. The method of claim 24 wherein said load bearing elastic body comprises a hydrophilic polymer comprising one or more materials selected from the group consisting of glucomannan gel, hyaluronic acid, and polysaccharides.

29. The method of claim 1 wherein said outer shell comprises a material selected from the group consisting of fibrin, albumin, collagen, elastin, silk, polyethylene oxide, cyanoacrylate, polylactic acid, polyglycolic acid, polypropylene fumarate, tyrosine-based polycarbonate, and demineralized bone matrix.

30. The method of claim 1 wherein said outer shell further includes a pharmacological agent.

31. The method of claim 30 wherein said pharmacological agent comprises a growth factor or an agent effective for treating degenerative disc disease, spinal arthritis, spinal infection, spinal tumor or osteoporosis.

32. The method of claim 31 wherein said growth factor comprises one or more members selected from the group consisting of bone morphogenetic protein, transforming growth factor-β

(TGF-β

), insulin-like growth factor, platelet-derived growth factor, and fibroblast growth factor.

33. The method of claim 30 wherein said pharmacological agent comprises one or more members selected from the group consisting of antibiotics, analgesics, and anti-inflammatory drugs, including steroids.

34. The method of claim 1 wherein said outer shell is introduced into said intervertebral disc space prior to introducing said elastic body into said intervertebral disc space.

35. The method of claim 1 wherein said outer shell is introduced into said intervertebral disc space after introducing said elastic body into said intervertebral disc space.

36. The method of claim 1 wherein said outer shell is introduced into said intervertebral disc space at the same time as said elastic body is introduced into said intervertebral disc space.

37. The method of claim 36 wherein said elastic body is provided with said outer shell prior to introducing said elastic body into said disc space.

38. The method of claim 1 wherein said load bearing elastic body comprises a load bearing elastic body sized for placement into an intervertebral disc space, said body having a first end, a second end, a central portion, and a first configuration wherein said first end and said second end are positioned adjacent to said central portion to form at least one inner fold, said elastic body configurable into a second, straightened configuration for insertion through an opening in an intervertebral disc annulus fibrosis, said body configurable back into said first configuration after said insertion;

wherein said body provides an implant having a substantially solid center when the body is in its first configuration.

39. The method of claim 1 wherein said load bearing elastic body comprises a load bearing elastic body having shape memory and sized for placement into an intervertebral disc space, said body having a first end, a second end, and a central portion;

wherein said shape memory biases said body to a first configuration wherein said first end and said second end are positioned adjacent to said central portion to form at least one inner fold and to provide a substantially solid center core when the implant is in its first configuration;

said elastic body configurable into a second, straightened configuration for insertion through an opening in an intervertebral disc annulus fibrosis;

wherein said shape memory returns said body to said first configuration after said insertion;

wherein said elastic body has a surface that includes wrinkles, indents or projections that relieve stress and prevent cracking or tearing of the implant when the implant is straightened for implantation.

40. A repaired intervertebral disc nucleus, comprising:

(a) a load bearing elastic body surgically implanted in an intervertebral disc space; and

(b) an outer shell around said load bearing elastic body;

wherein said outer shell comprises an amount of biocompatible material sufficient to substantially or completely fill the remaining intervertebral disc space.

41. The repaired intervertebral disc nucleus of claim 40 wherein said outer shell comprises a biocompatible material that has been injected around said elastic body.

42. The repaired intervertebral disc nucleus of claim 41 wherein said injected biocompatible material has been cured into a solid outer shell.

43. The repaired intervertebral disc nucleus of claim 42 wherein said solid outer shell is elastic.

44. The repaired intervertebral disc nucleus of claim 41 wherein said injected biocompatible material is an adhesive material.

45. The repaired intervertebral disc nucleus of claim 44 wherein said biocompatible adhesive material is a resorbable material.

46. The repaired intervertebral disc nucleus of claim 44 wherein said biocompatible adhesive material is a non-resorbable material.

47. The repaired intervertebral disc nucleus of claim 44 wherein said biocompatible adhesive material is a natural material.

48. The repaired intervertebral disc nucleus of claim 44 wherein said biocompatible adhesive material is a synthetic material.

49. The repaired intervertebral disc nucleus of claim 44 wherein said biocompatible adhesive material is a curable material.

50. The repaired intervertebral disc nucleus of claim 44 wherein said biocompatible adhesive material is a non-curable material.

51. The repaired intervertebral disc nucleus of claim 41 wherein said injected biocompatible material is a tissue sealant material.

52. The repaired intervertebral disc nucleus of claim 51 wherein said biocompatible tissue sealant material is a resorbable material.

53. The repaired intervertebral disc nucleus of claim 51 wherein said biocompatible tissue sealant material is a non-resorbable material.

54. The repaired intervertebral disc nucleus of claim 51 wherein said biocompatible tissue sealant material is a natural material.

55. The repaired intervertebral disc nucleus of claim 51 wherein said biocompatible tissue sealant material is a synthetic material.

56. The repaired intervertebral disc nucleus of claim 51 wherein said biocompatible tissue sealant material is a curable material.

57. The repaired intervertebral disc nucleus of claim 51 wherein said biocompatible tissue sealant material is a non-curable material.

58. The repaired intervertebral disc nucleus of claim 40 wherein said elastic body is sized to fill at least about 50% of the intervertebral disc space into which the implant is desired to be implanted.

59. The repaired intervertebral disc nucleus of claim 58 wherein said elastic body fills at least about 70% of the intervertebral disc space into which the implant is desired to be implanted.

60. The repaired intervertebral disc nucleus of claim 59 wherein said elastic body fills at least about 80% of the intervertebral disc space into which the implant is desired to be implanted.

61. The repaired intervertebral disc nucleus of claim 60 wherein said elastic body fills at least about 90% of the intervertebral disc space into which the implant is desired to be implanted.

62. The repaired intervertebral disc nucleus of claim 40 wherein said outer shell has a volume of between 1% and 50% of the volume of the composite implant.

63. The repaired intervertebral disc nucleus of claim 40 wherein said load bearing elastic body comprises a member selected from the group consisting of elastomeric materials, hydrogels, and hydrophilic polymers, or composites thereof.

64. The repaired intervertebral disc nucleus of claim 63 wherein said load bearing elastic body comprises an elastomeric material selected from the group consisting of silicone, polyurethane, copolymers of silicone and polyurethane, polyolefins, and vulcanized rubber.

65. The repaired intervertebral disc nucleus of claim 63 wherein said load bearing elastic body comprises a hydrogel comprising one or more materials selected from the group consisting of natural hydrogels, and hydrogels formed from polyvinyl alcohol, acrylamides, polyurethanes, polyethylene glycol, poly(N-vinyl-2-pyrrolidone), acrylates, copolymers of acrylates with N-vinyl pyrrolidone, N-vinyl lactams, acrylamide, polyurethanes and polyacrylonitrile.

66. The repaired intervertebral disc nucleus of claim 64 wherein said polyurethane comprises one or more materials selected from the group consisting of thermoplastic polyurethanes, aliphatic polyurethanes, segmented polyurethanes, hydrophilic polyurethanes, polyether-urethanes, polycarbonate-urethanes and silicone polyether-urethanes.

67. The repaired intervertebral disc nucleus of claim 63 wherein said load bearing elastic body comprises a hydrophilic polymer comprising one or more materials selected from the group consisting of glucomannan gel, hyaluronic acid, and polysaccharides.

68. The repaired intervertebral disc nucleus of claim 40 wherein said outer shell comprises a material selected from the group consisting of fibrin, albumin, collagen, elastin, silk, polyethylene oxide, cyanoacrylate, polylactic acid, polyglycolic acid, polypropylene fumarate, tyrosine-based polycarbonate, and demineralized bone matrix.

69. The repaired intervertebral disc nucleus of claim 40 wherein said outer shell further includes a pharmacological agent.

70. The repaired intervertebral disc nucleus of claim 69 wherein said pharmacological agent comprises a growth factor or an agent effective for treating degenerative disc disease, spinal arthritis, spinal infection, spinal tumor or osteoporosis.

71. The repaired intervertebral disc nucleus of claim 70 wherein said growth factor comprises one or more members selected from the group consisting of bone morphogenetic protein, transforming growth factor-β

(TGF-β

), insulin-like growth factor, platelet-derived growth factor, and fibroblast growth factor.

72. The repaired intervertebral disc nucleus of claim 69 wherein said pharmacological agent comprises one or more members selected from the group consisting of antibiotics, analgesics, and anti-inflammatory drugs, including steroids.

73. The repaired intervertebral disc nucleus of claim 40 wherein said load bearing elastic body comprises a load bearing elastic body sized for placement into an intervertebral disc space, said body having a first end, a second end, a central portion, and a first configuration wherein said first end and said second end are positioned adjacent to said central portion to form at least one inner fold, said elastic body configurable into a second, straightened configuration for insertion through an opening in an intervertebral disc annulus fibrosis, said body configurable back into said first configuration after said insertion;

wherein said body provides an implant having a substantially solid center when the body is in its first configuration.

74. The repaired intervertebral disc nucleus of claim 40 wherein said load bearing elastic body comprises a load bearing elastic body having shape memory and sized for placement into an intervertebral disc space, said body having a first end, a second end, and a central portion;

wherein said shape memory biases said body to a first configuration wherein said first end and said second end are positioned adjacent to said central portion to form at least one inner fold and to provide a substantially solid center core when the implant is in its first configuration;

said elastic body configurable into a second, straightened configuration for insertion through an opening in an intervertebral disc annulus fibrosis;

wherein said shape memory returns said body to said first configuration after said insertion;

wherein said elastic body has a surface that includes wrinkles, indents or projections that relieve stress and prevent cracking or tearing of the implant when the implant is straightened for implantation.

75. A kit for repairing an intervertebral disc nucleus, comprising a load bearing elastic body sized for introduction into an intervertebral disc space, and a container of biocompatible material sufficient to form an outer shell that substantially or completely fills a disc nucleus space.

76. The kit of claim 75 wherein said material is curable.

77. The kit of claim 75 wherein said material is resorbable.

78. The kit of claim 75 wherein said resorbable material comprises a material selected from the group consisting of fibrin, albumin, gelatin, collagen, elastin, silk, demineralized bone matrix, polyethylene oxide, polyethylene glycol, polyvinyl alcohol, polypropylene fumarate and combinations thereof.

79. The kit of claim 75 wherein said elastic body is comprised of a hydrogel material.

80. The kit of claim 75 wherein said elastic body is comprised of a polymer selected from the group consisting of elastomers and hydrogels.