Method for inserting frusto-conical interbody spinal fusion implants

• US 6,210,412 B1
• Filed: 06/07/1995
• Issued: 04/03/2001
• Est. Priority Date: 06/13/1988
• Status: Expired due to Term

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Gary K. Michelson
• Inventors: Michelson, Gary Karlin
• Primary Examiner(s): Brown, Michael A.
• Application Number:
  US08/480,904
• Time in Patent Office: 2,127 Days
• Field of Search: 606/61, 606/72-78, 623/16, 623/17, 623/18
• US Class Current: 606/86.00A
• CPC Class Codes: A61B 17/025 Joint distractors
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/32 Surgical cutting instruments A61B18/042 takes precedence; suture cutters A61B17/0467; instruments for ligaturing or cutting A61B17/128; instruments for rupturing the amniotic membrane A61B17/4208; specially adapted knives for eye surgery A61F9/0133
• CPC Class Codes: A61B 17/8888 at its central region
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61B 2017/922 Devices for impaction, impact element
• CPC Class Codes: A61B 2090/036 abutting on tissue or skin
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• 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 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2/4603 for insertion or extraction of endoprosthetic joints or of accessories thereof
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• 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 2002/3013 figure-"8"- or hourglass-shaped
• CPC Class Codes: A61F 2002/30131 horseshoe- or crescent- or C-shaped or U-shaped
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30148 lozenge- or diamond-shaped
• CPC Class Codes: A61F 2002/30224 : cylindrical
• CPC Class Codes: A61F 2002/30235 : tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30405 : made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30426 : Bayonet coupling
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30604 : modular
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30795 : Blind bores, e.g. of circular cross-section
• CPC Class Codes: A61F 2002/30797 : internally-threaded
• 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 2002/30879 : Ribs
• CPC Class Codes: A61F 2002/30904 : serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/30906 : shot- sand- or grit-blasted
• 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 2002/449 : comprising multiple spinal implants located in different intervertebral spaces or in different vertebrae
• CPC Class Codes: A61F 2002/4619 : for extraction
• 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 2002/4649 : Bone graft or bone dowel harvest sites
• CPC Class Codes: A61F 2002/4681 : by applying mechanical shocks, e.g. by hammering
• CPC Class Codes: A61F 2002/4687 : Mechanical guides for implantation instruments
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/001 : Figure-8-shaped, e.g. hourglass-shaped
• CPC Class Codes: A61F 2230/0013 : Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0063 : Nested prosthetic parts
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

The present invention is directed to a method of inserting a variety of interbody spinal fusion implants having at least a partially frusto-conical configuration and the instrumentation and methods by which the implants.

Claims

1. A method for inserting at least one frusto-conical spinal fusion implant made of a material appropriate for human implantation, said implant having bone engaging means for engaging the adjacent vertebrae in a segment of the spinal column, comprising the steps of:

distracting said adjacent vertebrae and placing said adjacent vertebrae in an angular relationship;

forming a frusto-conical bore from the anterior or posterior aspect of the spinal column across the distracted disc space between said adjacent vertebrae and into the adjacent vertebrae, said bore being at least in part greater in diameter than the distracted disc space such that some bone is removed from each of the adjacent vertebrae; and

inserting a frusto-conical spinal fusion implant into said bore.

2. The method of claim 1 in which said bore is greatest in diameter anteriorly and tapering to a lesser diameter posteriorly.

3. The method of claim 1 in which said bore is substantially cylindrical.

4. The method of claim 1 in which said step of forming includes the steps of using a drill having a substantially frusto-conical shaped bone removing portion.

5. The method of claim 1 further comprising the step of inserting a second spinal fusion implant across the disc space so as to engage each of the adjacent vertebrae, said second implant being side by side and adjacent to said first implant.

6. The method of claim 5 further comprising the steps of forming a second bore across the disc space partially overlapping said first bore, the combined width of said first and second bores being less than the sum of the individual diameters of said first and second bores;

and inserting said second implant.

7. The method of claim 1 in which the step of forming said bore includes the substep of removing a portion of bone parallel to the vertebral endplates of the adjacent vertebrae.

8. The method of claim 1, wherein the distracting step includes the step of inserting a spinal distractor into the disc space between the adjacent vertebrae to induce angulation to the adjacent vertebrae.

9. The method of claim 8, further comprising the step of positioning a sleeve over said spinal distractor and into contact with the adjacent vertebrae.

10. The method of claim 9, further comprising the step of removing said spinal distractor prior to the step of forming.

11. The method of claim 9, wherein the positioning step includes the step of positioning a sleeve having an extension for insertion into the disc space and for bearing against end plates of the adjacent vertebrae.

12. The method of claim 11, wherein the positioning step includes the sub-step of inducing angulation to the adjacent vertebrae.

13. The method of claim 12, wherein the inducing angulation step includes the step of restoring lordosis to the adjacent vertebrae.

14. The method of claim 12, wherein the inducing angulation step includes the step of restoring kyphosis to the asdjacent vertebrae.

15. The method of claim 9, wherein the forming step includes the sub-step of drilling the bore.

16. The method of claim 15, wherein the forming step further comprises the sub-step of placing a drill having a diameter greater than the disc space through said sleeve prior to the sub-step of drilling.

17. The method of claim 9, wherein the step of inserting includes the sub-step of inserting said implant through said sleeve and into the bore.

18. The method of claim 9, further comprising the step of placing an inner sleeve within said sleeve prior to the step of forming the bore.

19. The method of claim 18, further comprising the step of removing said inner sleeve prior to the step of inserting said implant.

20. The method of claim 1, wherein the forming step includes the sub-step of milling the bore.

21. The method of claim 1, further comprising the step of loading said implant with fusion promoting material prior to the step of inserting.

22. The method of claim 1, further comprising the step of loading said implant with osteogenic material prior to the step of inserting.

23. The method of claim 1, further comprising the step of coating said implant with bone morphogenic proteins prior to the step of inserting.

24. The method of claim 1, wherein the step of inserting includes inserting an implant containing a fusion promoting substance.

25. The method of claim 1, wherein the step of inserting includes inserting an implant comprising a fusion promoting substance.

26. The method of claim 1, wherein the step of inserting includes inserting an implant comprising a bone ingrowth surface.

29. The method of claim 22 in which said step of forming the step of includes using a drill having a substantially cylindrical shaped bone removing portion.

30. The method of claim 22 further comprising the step of inserting a second spinal fusion implant across the disc space so as to engage each of the adjacent vertebrae, said second implant being side by side and adjacent to said first implant.

31. The method of claim 30 further comprising the steps of forming a second bore across the disc space partially overlapping said first bore, the combined width of said first and second bores being less than the sum of the individual diameters of said first and second bores;

and inserting said second spinal fusion implant into said second bore.

46. The method of claim 22, further comprising the step of loading said implant with fusion promoting material prior to the step of inserting.

27. A method for inserting at least one frusto-conical spinal fusion implant made of a material appropriate for human implantation, said implant having bone engaging means for engaging the adjacent vertebrae in a segment of the spinal column, comprising the steps of:

distracting the adjacent vertebrae;

forming a bore from the anterior or posterior aspect of the spinal column across the disc space and into the adjacent vertebrae, said bore being at least in part greater in diameter than the disc space between the distracted vertebrae such that some bone is removed from each of the adjacent vertebrae; and

inserting a frusto-conical spinal fusion implant into said bore.

28. The method of claim 27 in which said bore is generally cylindrical in shape.

32. The method of claim 27 in which the step of forming said bore includes the substep of removing a portion of bone parallel to the endplates of the adjacent vertebrae.

33. The method of claim 27, wherein the distracting step includes the step of inserting a spinal distractor into the disc space between the adjacent vertebrae to induce angulation to the adjacent vertebrae.

34. The method of claim 33, further comprising the step of positioning a sleeve over said spinal distractor and into contact with the adjacent vertebrae.

35. The method of claim 34, further comprising the step of removing said spinal distractor prior to the step of forming.

36. The method of claim 41, wherein the positioning step includes the step of positioning a sleeve having an extension for insertion into the disc space and for bearing against end plates of the adjacent vertebrae.

37. The method of claim 34, wherein the positioning step includes the sub-step of inducing angulation to the adjacent vertebrae.

38. The method of claim 37, wherein the inducing angulation step includes the step of restoring lordosis to the adjacent vertebrae.

39. The method of claim 37, wherein the inducing angulation step includes the step of restoring kyphosis to the adjacent vertebrae.

40. The method of claim 34, wherein the forming step includes the sub-step of drilling the bore.

41. The method of claim 40, wherein the forming step further comprises the sub-step of placing a drill having a diameter greater than the disc space through said sleeve prior to the sub-step of drilling.

42. The method of claim 41, further comprising the step of placing an inner sleeve within said sleeve prior to the step of forming the bore.

43. The method of claim 42, further comprising the step of removing said inner sleeve prior to the step of inserting said implant.

44. The method of claim 34, wherein the step of inserting includes the sub-step of inserting said implant through said sleeve and into the bore.

45. The method of claim 27, wherein the forming step includes the sub-step of milling the bore.

47. The method of claim 27, further comprising the step of loading said implant with osteogenic material prior to the step of inserting.

48. The method of claim 27, further comprising the step of coating said implant with bone morphogenic proteins prior to the step of inserting.

49. The method of claim 27, wherein the step of inserting includes inserting an implant containing a fusion promoting substance.

50. The method of claim 27, wherein the step of inserting includes inserting an implant comprising a fusion promoting substance.

51. The method of claim 27, wherein the step of inserting includes inserting an implant comprising a bone ingrowth surface.

52. A method for inserting a spinal implant across a disc space between adjacent vertebrae of a human spine, comprising the steps of:

distracting said adjacent vertebrae to induce angulation to the adjacent vertebrae;

forming a bore from the anterior or posterior aspect of the spinal column across the distracted disc space between said adjacent vertebrae and into the adjacent vertebrae, said bore having opposed arcuate portions in an angular relationship to one another along at least a portion of each of the adjacent vertebrae; and

inserting into said bore said spinal implant having opposed arcuate portions in an angular relationship to one another along the length of said implant and oriented toward the adjacent vertebrae.

53. The method of claim 52, wherein the distracting step includes the step of inserting a spinal distractor into the disc space between the adjacent vertebrae to induce angulation to the adjacent vertebrae.

54. The method of claim 53, further comprising the step of positioning a sleeve over said spinal distractor and into contact with the adjacent vertebrae.

55. The method of claim 52, further comprising the step of removing said spinal distractor prior to the step of forming.

56. The method of claim 54, wherein the positioning step includes the step of positioning a sleeve having an extension for insertion into the disc space and for bearing against end plates of the adjacent vertebrae.

57. The method of claim 56, wherein the positioning step includes the sub-step of inducing angulation to the adjacent vertebrae.

58. The method of claim 57, wherein the inducing angulation step includes the step of restoring lordosis to the adjacent vertebrae.

59. The method of claim 57, wherein the inducing angulation step includes the step of restoring kyphosis.

60. The method of claim 54, wherein the forming step includes the sub-step of drilling the bore.

61. The method of claim 60, wherein the forming step further comprises the sub-step of placing a drill having a diameter greater than the disc space through said sleeve prior to the sub-step of drilling.

62. The method of claim 54, wherein the step of inserting includes the sub-step of inserting said implant through said sleeve and into the bore.

63. The method of claim 54, further comprising the step of placing an inner sleeve within said sleeve prior to the step of forming the bore.

64. The method of claim 63, further comprising the step of removing said inner sleeve prior to the step of inserting said implant.

65. The method of claim 52, wherein the forming step includes the sub-step of milling the bore.

66. The method of claim 52, further comprising the step of loading said implant with fusion promoting material prior to the step of inserting.

67. The method of claim 54, further comprising the step of loading said implant with osteogenic material prior to the step of inserting.

68. The method of claim 52, further comprising the step of coating said implant with bone morphogenic proteins prior to the step of inserting.

69. The method of claim 52, wherein the step of inserting includes inserting an implant containing a fusion promoting substance.

70. The method of claim 52, wherein the step of inserting includes inserting an implant comprising a fusion promoting substance.

71. The method of claim 52, wherein the step of inserting includes inserting an implant comprising a bone ingrowth surface.

72. A method for inserting a spinal implant across a disc space between adjacent vertebrae of a human spine, comprising the steps of:

forming a bore from the anterior or posterior aspect of the spinal column across the disc space and into the adjacent vertebrae, said bore being at least in part greater in diameter than the distracted disc space such that some bone is removed from each of the adjacent vertebrae; and

inserting into said bore said spinal implant having opposed arcuate portions oriented toward the adjacent vertebrae, said arcuate portions being in a diverging relationship to one another along the length of said implant sufficient to induce angulation of the vertebrae.

73. The method of claim 72, further comprising the step of distracting the adjacent vertebrae prior to the forming step.

74. The method of claim 73, wherein the distracting step includes the step of inserting a spinal distractor into the disc space between the adjacent vertebrae to induce angulation to the adjacent vertebrae.

75. The method of claim 74, further comprising the step of positioning a sleeve over said spinal distractor and into contact with the adjacent vertebrae.

76. The method of claim 75, further comprising the step of removing said spinal distractor prior to the step of forming.

77. The method of claim 75, wherein the positioning step includes the step of positioning a sleeve having an extension for insertion into the disc space and for bearing against end plates of the adjacent vertebrae.

78. The method of claim 77, wherein the positioning step includes the sub-step of inducing angulation to the adjacent vertebrae.

79. The method of claim 78, wherein the inducing angulation step includes the step of restoring lordosis to the adjacent vertebrae.

80. The method of claim 78, wherein the inducing angulation step includes the step of restoring kyphosis.

81. The method of claim 75, wherein the forming step includes the sub-step of drilling the bore.

82. The method of claim 81, wherein the forming step further comprises the sub-step of placing a drill having a diameter greater than the disc space through said sleeve prior to the sub-step of drilling.

83. The method of claim 75, wherein the step of inserting includes the sub-step of inserting said implant through said sleeve and into the bore.

84. The method of claim 75, further comprising the step of placing an inner sleeve within said sleeve prior to the step of forming the bore.

85. The method of claim 84, further comprising the step of removing said inner sleeve prior to the step of inserting said implant.

86. The method of claim 72, wherein the forming step includes the sub-step of milling the bore.

87. The method of claim 72, further comprising the step of loading said implant with fusion promoting material prior to the step of inserting.

88. The method of claim 72, further comprising the step of loading said implant with osteogenic material prior to the step of inserting.

89. The method of claim 72, further comprising the step of coating said implant with bone morphogenic proteins prior to the step of inserting.

90. The method of claim 72, wherein the step of inserting includes inserting an implant containing a fusion promoting substance.

91. The method of claim 72, wherein the step of inserting includes inserting an implant comprising a fusion promoting substance.

92. The method of claim 72, wherein the step of inserting includes inserting an implant comprising a bone ingrowth surface.