Instrumentation for the surgical correction of human thoracic and lumbar spinal disease from the lateral aspect of the spine

• US 7,491,205 B1
• Filed: 06/07/1995
• Issued: 02/17/2009
• Est. Priority Date: 06/13/1988
• Status: Active Grant

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Inventors: Michelson, Gary Karlin
• Primary Examiner(s): BROWN, MICHAEL A
• Application Number:
  US08/480,461
• Time in Patent Office: 5,004 Days
• Field of Search: 606 60- 61, 606/57, 606/90, 606/246, 623/16, 623/17, 623/17.11
• US Class Current: 606/90
• CPC Class Codes: A61B 17/025 Joint distractors
• CPC Class Codes: A61B 17/0642 for bones, e.g. for osteosynthesis or connecting tendon to bone
• CPC Class Codes: A61B 17/1604 Chisels; Rongeurs; Punches; Stamps
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/17 Guides or aligning means for drills , mills, pins or wires
• 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 17/320016 Endoscopic cutting instruments, e.g. arthroscopes, resectoscopes A61B10/0233, A61B17/29, A61B17/3207 take precedence
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/809 with bone-penetrating elements, e.g. blades or prongs bone staples A61B17/0642; intramedullary nails with a plate at an end A61B17/7233
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61B 17/8665 Nuts
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61B 2017/00004 (bio)absorbable, (bio)resorbable, resorptive for implantable prostheses A61F2210/0004
• CPC Class Codes: A61B 2017/00261 Discectomy
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61B 2017/0641 having at least three legs as part of one single body
• CPC Class Codes: A61B 2017/0647 having one single leg, e.g. tacks
• CPC Class Codes: A61B 2017/0648 threaded, e.g. tacks with a screw thread
• 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 2/30965 : Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/442 : Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4455 : for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/446 : having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 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 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 2002/30062 : (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30143 : hexagonal
• CPC Class Codes: A61F 2002/30224 : cylindrical
• CPC Class Codes: A61F 2002/30235 : tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30329 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• 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 2002/30433 : using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30772 : Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• 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 2002/30904 : serrated profile, i.e. saw-toothed
• 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 2210/0004 : bioabsorbable
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00059 : Chromium or Cr-based alloys
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

An improved method and instrumentation for performing spinal surgery, including discectomy, interbody fusion and rigid internal fixation of the spine, from the lateral aspect of the spine is disclosed. The surgical procedure can be performed through a very small incision. The instrumentation of the present invention, all of which is inserted from a lateral position into the spine in the preferred embodiment, comprises a guide pin, a distractor, an extended outer sleeve, an inner sleeve an adjustable drill and an implant driver. The distractor of the present invention is driven into the disc for spacing apart and realigning the adjacent vertebrae. It further functions as an alignment rod for inserting the extended outer sleeve which is a hollow tubular member capable of maintaining said spacing and alignment of two adjacent vertebrae and defines a protected space through which subsequent instruments which may include, but are not limited to, a drill and a diameter reducing inner sleeve may be passed, as well as a spinal implant. The remainder of the surgical procedure consisting of the removal of spinal material across the disc, fusion, and rigid internal stabilization via the implant may all be performed via the closed space within the extended outer sleeve.

Claims

1. A spinal distractor for use in spinal fusion surgery within an adult human thoracic and lumbar spine for positioning adjacent vertebral bodies of two adjacent vertebrae adjacent a disc space in selected relationship to each other, said spinal distractor comprising:

a body having a height adapted to be greater than the height of the disc space; and

at least one disc penetrating extension extending from said body adapted to be inserted into the lateral aspect of the disc space from a position anterior to the transverse processes of the adjacent vertebrae, said disc penetrating extension having a portion adapted to bear against each of the adjacent endplates of the two adjacent vertebral bodies, said portion of said disc penetrating extension having a height less than the height of said body and a length that is less than the transverse width of the vertebral bodies between which said disc penetrating extension is adapted to be inserted, said length being greater than the depth of the spinal disc intermediate the two adjacent vertebral bodies between which said disc penetrating extension is adapted to be inserted.

2. The spinal distractor of claim 1, further comprising means for limiting the penetration of said disc penetrating extension into the disc space.

3. The spinal distractor of claim 2, wherein said limiting means comprises a shoulder on said body at the juncture of said disc penetrating extension and said body for preventing said body from entering the disc space.

4. The spinal distractor of claim 1, wherein said disc penetrating extension has a tapered front end to facilitate insertion of said disc penetrating extension into the disc space.

5. The spinal distractor of claim 1, wherein said body has a longitudinal passageway adapted to receive an alignment pin.

6. The spinal distractor of claim 1, wherein said body has means for engaging an extraction device for extracting said disc penetrating extension from the disc space.

7. The spinal distractor of claim 6, wherein said engaging means includes a mating member for mating with an extraction device.

8. An apparatus for use in spinal fusion surgery, said apparatus comprising:

a spinal distractor for positioning adjacent vertebral bodies of two adjacent vertebrae adjacent a disc space in selected relationship to each other, said spinal distractor comprising;

a body having a height greater than the height of the disc space; and

at least one disc penetrating extension extending from said body for insertion into the lateral aspect of the disc space from a position anterior to the transverse processes of the adjacent vertebrae, said disc penetrating extension having a portion for bearing against each of the adjacent endplates of the two adjacent vertebral bodies, said portion of said disc penetrating extension having a height less than the height of said body and a length that is less than the transverse width of the vertebral bodies, said length being greater than the depth of the spinal disc intermediate the two adjacent vertebral bodies between which said disc penetrating extension is inserted; and

a guard having an opening for providing protected access to the disc space and the adjacent vertebral bodies, said spinal distractor passing through said opening.

9. The spinal distractor and guard combination of claim 8, wherein said guard maintains said spinal distractor in coaxial alignment with the longitudinal axis of the opening.

10. The spinal distractor and guard combination of claim 9, further in combination with a spinal implant having upper and lower surfaces for bearing upon and supporting each of the two adjacent vertebral bodies, said spinal implant passing through said opening of said guard.

11. The spinal distractor, guard, and spinal implant combination of claim 10, wherein said guard maintains said spinal implant in coaxial alignment with the longitudinal axis of the opening of said guard.

12. The spinal distractor and guard combination of claim 8, further in combination with a bone removal device having a portion sized for passage through said opening of said guard for forming through said guard an implantation space across the disc space.

13. The spinal distractor, guard, and bone removal device combination of claim 12, further in combination with an implant driver having means for engaging an implant, said implant driver having a portion sized for passage through said opening of said guard for passing an implant through said guard.

14. An apparatus for use in human spinal surgery across the height of a disc space between the vertebral bodies of two adjacent vertebrae, said apparatus comprising:

a guard member having a height adapted to be greater than the height of the disc space and an opening for providing protected access to the lateral aspect of the disc space and the adjacent vertebral bodies from a position anterior to the transverse processes of the adjacent vertebrae, said opening having a maximum height; and

at least one disc penetrating extension extending from said guard member adapted to be inserted into the lateral aspect of the disc space from a position anterior to the transverse processes of the adjacent vertebrae, said disc penetrating extension having a portion adapted to bear against each of the adjacent endplates of the adjacent vertebral bodies, said portion of said disc penetrating extension having a height less than the height of said guard member and a length that is less than the transverse width of the vertebral bodies between which said disc penetrating extension is adapted to be inserted, said length being greater than the depth of the disc space in which said length is adapted to be inserted, said portion of said disc penetrating extension having an upper surface adapted to contact one of the adjacent endplates of the adjacent vertebral bodies and a lower surface adapted to contact the other of the adjacent endplates of the adjacent vertebral bodies at more than one point through the disc space.

15. The apparatus of claim 14, wherein said upper and lower surfaces are at least in part parallel to each other.

16. The apparatus of claim 14, wherein said guard member has an external surface at its distal end and said disc penetrating extension is at least in part coextensive with said external surface.

17. The apparatus of claim 14, further comprising a second disc penetrating extension extending from said guard member for insertion into the disc space and for bearing against the endplates of the adjacent vertebral bodies.

18. The apparatus of claim 17, wherein said disc penetrating extensions are diametrically opposed to each other.

19. The apparatus of claim 17, wherein said disc penetrating extensions have the same height.

22. The apparatus of claim 14, wherein said portion of said disc penetrating extension has a height between said upper and lower surfaces that approximates the height of the normal disc space between the adjacent vertebral bodies.

23. The apparatus of claim 14, wherein said guard member conforms at least in part to the exterior surface of the vertebral bodies of the lateral aspect of the adjacent vertebral bodies.

24. The apparatus of claim 23, wherein said upper and lower surfaces are at least in part parallel to each other.

25. The apparatus of claim 23, further comprising a second disc penetrating extension extending from said guard member for insertion into the disc space and for bearing against the endplates of the adjacent vertebral bodies.

26. The apparatus of claim 25, wherein said disc penetrating extensions are diametrically opposed to each other.

27. The apparatus of claim 25, wherein said disc penetrating extensions have the same height.

28. The apparatus of claim 25, wherein said disc penetrating extensions are of a different height.

29. The apparatus of claim 25, wherein said disc penetrating extensions are of a different length.

30. The apparatus of claim 23, wherein said portion of said disc penetrating extension has a height between said upper and lower surfaces that approximates the height of the normal disc space between the adjacent vertebral bodies.

31. The apparatus of claim 14, further comprising means for penetrating the two adjacent vertebral bodies.

32. The apparatus of claim 31, wherein said penetrating means includes teeth for insertion into the spine.

33. The apparatus of claim 31, wherein said penetrating means includes at least one prong for insertion into the spine.

34. The apparatus of claim 14, further comprising a removable inner sleeve.

35. The apparatus of claim 14, further comprising means for limiting the depth of penetration of said disc penetrating extension into the disc space.

36. The apparatus of claim 14, wherein said guard member comprises a hollow tube.

38. The apparatus of claim 14, wherein said disc penetrating extension has a tapered leading end to facilitate placement of said disc penetrating extension into the disc space.

39. The apparatus of claim 14 in combination with a bone removal device having a portion sized for passage through said opening of said guard for forming through said opening of said guard member an implantation space across the disc space.

40. The apparatus of claim 39 in combination with an implant driver sized in part for passage through said opening of said guard for passing an implant through said guard member and into the disc space.

41. The apparatus of claim 14 in combination with a spinal distractor sized for passage through said guard member, said spinal distractor having a body and a disc penetrating member extending from said body and into the disc space between the two adjacent vertebral bodies for bearing against the adjacent endplates of the two adjacent vertebral bodies.

42. The apparatus of claim 41, wherein said disc penetrating member has a tapered leading end to facilitate placement of said disc penetrating member into the disc space.

43. The apparatus of claim 14 in combination with a tap for insertion through said guard member for tapping the two adjacent vertebral bodies.

20. An apparatus for use in human spinal surgery across a disc space between the vertebral bodies of two adjacent vertebrae, comprising:

a guard member having a height greater than the height of the disc space and an opening for providing protected access to the lateral aspect of the disc space and the adjacent vertebral bodies from a position anterior to the transverse processes of the adjacent vertebrae, said opening having a maximum height; and

at least two disc penetrating extensions extending from said guard member for insertion into the lateral aspect of the disc space from a position anterior to the transverse processes of the adjacent vertebrae, said disc penetrating extensions having a portion for bearing against each of the adjacent endplates of the adjacent vertebral bodies, said portion of said disc penetrating extensions having a height less than the height of said guard member and a length that is less than the transverse width of the vertebral bodies, said length being greater than the depth of the disc space, said portion of said disc penetrating extensions having an upper surface adapted to contact one of the adjacent endplates of the adjacent vertebral bodies and a lower surface adapted to contact the other of the adjacent endplates of the adjacent vertebral bodies at more than one point through the disc space, said disc penetrating extensions being of a different height.

46. The apparatus of claim 20, wherein said upper and lower surfaces are at least in part parallel to each other.

47. The apparatus of claim 20, wherein said guard member has an external surface at its distal end and said disc penetrating extensions are at least in part coextensive with said external surface.

48. The apparatus of claim 20, wherein said disc penetrating extensions are diametrically opposed to each other.

49. The apparatus of claim 20, wherein said disc penetrating extensions are of a different length.

50. The apparatus of claim 20, wherein said portion of said disc penetrating extension has a height between said upper and lower surfaces that approximates the height of the normal disc space between the adjacent vertebral bodies.

51. The apparatus of claim 20, wherein said guard member conforms at least in part to the exterior surface of the vertebral bodies of the lateral aspect of the adjacent vertebral bodies.

52. The apparatus of claim 20, further comprising means for penetrating the two adjacent vertebral bodies.

53. The apparatus of claim 52, wherein said penetrating means includes teeth for insertion into the spine.

54. The apparatus of claim 52, wherein said penetrating means includes at least one prong for insertion into the spine.

55. The apparatus of claim 20, further comprising a removable inner sleeve.

56. The apparatus of claim 20, further comprising means for limiting the depth of penetration of said disc penetrating extensions into the disc space.

57. The apparatus of claim 20, wherein said guard member comprises a hollow tube.

58. The apparatus of claim 57, wherein said hollow tube has a detachable distal end portion.

59. The apparatus of claim 20, wherein said disc penetrating extensions have a tapered leading end to facilitate placement of said disc penetrating extensions into the disc space.

60. The apparatus of claim 20 in combination with a bone removal device having a portion sized for passage through said opening of said guard for forming through said opening of said guard member an implantation space across the disc space.

61. The apparatus of claim 20 in combination with an implant driver sized in part for passage through said opening of said guard for passing an implant through said guard member and into the disc space.

62. The apparatus of claim 20 in combination with a spinal distractor sized for passage through said guard member, said spinal distractor having a body and a disc penetrating member extending from said body and into the disc space between the two adjacent vertebral bodies for bearing against the adjacent endplates of the two adjacent vertebral bodies.

63. The apparatus of claim 62, wherein said disc penetrating member has a tapered leading end to facilitate placement of said disc penetrating member into the disc space.

64. The apparatus of claim 20 in combination with a tap for insertion through said guard member for tapping the two adjacent vertebral bodies.

65. The apparatus of claim 20, further comprising an extractor coupler having one end adapted to couple with said guard member and an opposite end adapted to couple with an extraction device.

68. The apparatus of claim 20, wherein said disc penetrating extensions have the same height.

21. An apparatus for use in human spinal surgery across a disc space between the vertebral bodies of two adjacent vertebrae, comprising:

a guard member having a height greater than the height of the disc space and an opening for providing protected access to the lateral aspect of the disc space and the adjacent vertebral bodies from a position anterior to the transverse processes of the adjacent vertebrae, said opening having a maximum height; and

at least two disc penetrating extensions extending from said guard member for insertion into the lateral aspect of the disc space from a position anterior to the transverse processes of the adjacent vertebrae, said disc penetrating extensions having a portion for bearing against each of the adjacent endplates of the adjacent vertebral bodies, said portion of said disc penetrating extensions having a height less than the height of said guard member and a length that is less than the transverse width of the vertebral bodies, said length being greater than the depth of the disc space, said portion of said disc penetrating extensions having an upper surface adapted to contact one of the adjacent endplates of the adjacent vertebral bodies and a lower surface adapted to contact the other of the adjacent endplates of the adjacent vertebral bodies at more than one point through the disc space, said disc penetrating extensions being of a different length.

66. The apparatus of claim 21, wherein said upper and lower surfaces are at least in part parallel to each other.

67. The apparatus of claim 21, wherein said guard member has an external surface at its distal end and said disc penetrating extensions are at least in part coextensive with said external surface.

69. The apparatus of claim 21, wherein said disc penetrating extensions are diametrically opposed to each other.

70. The apparatus of claim 21, wherein said portion of said disc penetrating extension has a height between said upper and lower surfaces that approximates the height of the normal disc space between the adjacent vertebral bodies.

71. The apparatus of claim 21, wherein said guard member conforms at least in part to the exterior surface of the vertebral bodies of the lateral aspect of the adjacent vertebral bodies.

72. The apparatus of claim 21, further comprising means for penetrating the two adjacent vertebral bodies.

73. The apparatus of claim 72, wherein said penetrating means includes teeth for insertion into the spine.

74. The apparatus of claim 72, wherein said penetrating means includes at least one prong for insertion into the spine.

75. The apparatus of claim 21, further comprising a removable inner sleeve.

76. The apparatus of claim 21, further comprising means for limiting the depth of penetration of said disc penetrating extensions into the disc space.

77. The apparatus of claim 21, wherein said guard member comprises a hollow tube.

78. The apparatus of claim 77, wherein said hollow tube has a detachable distal end portion.

79. The apparatus of claim 21, wherein said disc penetrating extensions have a tapered leading end to facilitate placement of said disc penetrating extensions into the disc space.

80. The apparatus of claim 21 in combination with a bone removal device having a portion sized for passage through said opening of said guard for forming through said opening of said guard member an implantation space across the disc space.

81. The apparatus of claim 21 in combination with an implant driver sized in part for passage through said opening of said guard for passing an implant through said guard member and into the disc space.

82. The apparatus of claim 21 in combination with a spinal distractor sized for passage through said guard member, said spinal distractor having a body and a disc penetrating member extending from said body and into the disc space between the two adjacent vertebral bodies for bearing against the adjacent endplates of the two adjacent vertebral bodies.

83. The apparatus of claim 82, wherein said disc penetrating member has a tapered leading end to facilitate placement of said disc penetrating member into the disc space.

84. The apparatus of claim 21 in combination with a tap for insertion through said guard member for tapping the two adjacent vertebral bodies.

85. The apparatus of claim 21, further comprising an extractor coupler having one end adapted to couple with said guard member and an opposite end adapted to couple with an extraction device.

37. An apparatus for use in human spinal surgery across a disc space between the vertebral bodies of two adjacent vertebrae, comprising:

a guard member including a hollow tube having a height greater than the height of the disc space and an opening for providing protected access to the lateral aspect of the disc space and the adjacent vertebral bodies from a position anterior to the transverse processes of the adjacent vertebrae, said opening having a maximum height, said hollow tube having a detachable distal end portion; and

at least one disc penetrating extension extending from said guard member for insertion into the lateral aspect of the disc space from a position anterior to the transverse processes of the adjacent vertebrae, said disc penetrating extension having a portion for bearing against each of the adjacent endplates of the adjacent vertebral bodies, said portion of said disc penetrating extension having a height less than the height of said guard member and a length that is less than the transverse width of the vertebral bodies, said length being greater than the depth of the disc space, said portion of said disc penetrating extension having an upper surface adapted to contact one of the adjacent endplates of the adjacent vertebral bodies and a lower surface adapted to contact the other of the adjacent endplates of the adjacent vertebral bodies at more than one point through the disc space.

86. The apparatus of claim 37, wherein said upper and lower surfaces are at least in part parallel to each other.

87. The apparatus of claim 37, wherein said guard member has an external surface at its distal end and said disc penetrating extension is at least in part coextensive with said external surface.

88. The apparatus of claim 37, further comprising a second disc penetrating extension extending from said guard member for insertion into the disc space and for bearing against the endplates of the adjacent vertebral bodies.

89. The apparatus of claim 88, wherein said disc penetrating extensions are diametrically opposed to each other.

90. The apparatus of claim 88, wherein said disc penetrating extensions have the same height.

91. The apparatus of claim 88, wherein said disc penetrating extensions are of a different height.

92. The apparatus of claim 88, wherein said disc penetrating extensions are of a different length.

93. The apparatus of claim 37, wherein said portion of said disc penetrating extension has a height between said upper and lower surfaces that approximates the height of the normal disc space between the adjacent vertebral bodies.

94. The apparatus of claim 37, wherein said guard member conforms at least in part to the exterior surface of the vertebral bodies of the lateral aspect of the adjacent vertebral bodies.

95. The apparatus of claim 94, wherein said upper and lower surfaces are at least in part parallel to each other.

96. The apparatus of claim 94, further comprising a second disc penetrating extension extending from said guard member for insertion into the disc space and for bearing against the endplates of the adjacent vertebral bodies.

97. The apparatus of claim 96, wherein said disc penetrating extensions are diametrically opposed to each other.

98. The apparatus of claim 96, wherein said disc penetrating extensions have the same height.

99. The apparatus of claim 96, wherein said disc penetrating extensions are of a different height.

100. The apparatus of claim 96, wherein said disc penetrating extensions are of a different length.

101. The apparatus of claim 94, wherein said portion of said disc penetrating extension has a height between said upper and lower surfaces that approximates the height of the normal disc space between the adjacent vertebral bodies.

102. The apparatus of claim 37, further comprising means for penetrating the two adjacent vertebral bodies.

103. The apparatus of claim 102, wherein said penetrating means includes teeth for insertion into the spine.

104. The apparatus of claim 102, wherein said penetrating means includes at least one prong for insertion into the spine.

105. The apparatus of claim 37, further comprising a removable inner sleeve.

106. The apparatus of claim 37, further comprising means for limiting the depth of penetration of said disc penetrating extension into the disc space.

107. The apparatus of claim 37, wherein said disc penetrating extension has a tapered leading end to facilitate placement of said disc penetrating extension into the disc space.

108. The apparatus of claim 37 in combination with a bone removal device having a portion sized for passage through said opening of said guard for forming through said opening of said guard member an implantation space across the disc space.

109. The apparatus of claim 37 in combination with an implant driver sized in part for passage through said opening of said guard for passing an implant through said guard member and into the disc space.

110. The apparatus of claim 37 in combination with a spinal distractor sized for passage through said guard member, said spinal distractor having a body and a disc penetrating member extending from said body and into the disc space between the two adjacent vertebral bodies for bearing against the adjacent endplates of the two adjacent vertebral bodies.

111. The apparatus of claim 110, wherein said disc penetrating member has a tapered leading end to facilitate placement of said disc penetrating member into the disc space.

112. The apparatus of claim 37 in combination with a tap for insertion through said guard member for tapping the two adjacent vertebral bodies.

113. The apparatus of claim 37, further comprising an extractor coupler having one end adapted to couple with said guard member and an opposite end adapted to couple with an extraction device.

44. An apparatus for use in human spinal surgery across a disc space between the vertebral bodies of two adjacent vertebrae, comprising:

a guard member having a height greater than the height of the disc space and an opening for providing protected access to the lateral aspect of the disc space and the adjacent vertebral bodies from a position anterior to the transverse processes of the adjacent vertebrae, said opening having a maximum height;

at least one disc penetrating extension extending from said guard member for insertion into the lateral aspect of the disc space from a position anterior to the transverse processes of the adjacent vertebrae, said disc penetrating extension having a portion for bearing against each of the adjacent endplates of the adjacent vertebral bodies, said portion of said disc penetrating extension having a height less than the height of said guard member and a length that is less than the transverse width of the vertebral bodies, said length being greater than the depth of the disc space, said portion of said disc penetrating extension having an upper surface adapted to contact one of the adjacent endplates of the adjacent vertebral bodies and a lower surface adapted to contact the other of the adjacent endplates of the adjacent vertebral bodies at more than one point through the disc space; and

an extractor coupler having one end adapted to couple with said guard member and an opposite end adapted to couple with an extraction device.

45. An apparatus for use in human interbody spinal surgery across a disc space between the vertebral bodies of two adjacent vertebrae, comprising:

a guard member having a proximal end, a distal end, a height greater than the height of the disc space, and at least one passageway adapted to permit the passage of a bone removal device therethrough for providing protected access to the disc space and the adjacent vertebral bodies, said passage having a maximum height; and

at least one disc penetrating extension extending from said distal end of said guard member for insertion into the disc space, said disc penetrating extension being separable from said proximal end of said guard, said disc penetrating extension having a portion for bearing against each of the adjacent endplates of the adjacent vertebral bodies, said portion of said disc penetrating extension having an upper surface adapted to contact one of the adjacent endplates of the adjacent vertebral bodies and a lower surface adapted to contact the other of the adjacent endplates of the adjacent vertebral bodies intermediate the two adjacent vertebral bodies between which said disc penetrating extension is inserted.

114. The apparatus of claim 45, wherein said upper and lower surfaces are at least in part parallel to each other.

115. The apparatus of claim 45, wherein said guard member has an external surface at its distal end and said disc penetrating extension is at least in part coextensive with said external surface.

116. The apparatus of claim 45, further comprising a second disc penetrating extension extending from said guard member for insertion into the disc space and for bearing against the endplates of the adjacent vertebral bodies.

117. The apparatus of claim 116, wherein said disc penetrating extensions are diametrically opposed to each other.

118. The apparatus of claim 116, wherein said disc penetrating extensions have the same height.

119. The apparatus of claim 116, wherein said disc penetrating extensions are of a different height.

120. The apparatus of claim 116, wherein said disc penetrating extensions are of a different length.

121. The apparatus of claim 45, wherein said portion of said disc penetrating extension has a height between said upper and lower surfaces that approximates the height of the normal disc space between the adjacent vertebral bodies.

122. The apparatus of claim 45, wherein said guard member conforms at least in part to the exterior surface of the vertebral bodies of the lateral aspect of the adjacent vertebral bodies.

123. The apparatus of claim 122, wherein said upper and lower surfaces are at least in part parallel to each other.

124. The apparatus of claim 122, further comprising a second disc penetrating extension extending from said guard member for insertion into the disc space and for bearing against the endplates of the adjacent vertebral bodies.

125. The apparatus of claim 124, wherein said disc penetrating extensions are diametrically opposed to each other.

126. The apparatus of claim 124, wherein said disc penetrating extensions have the same height.

127. The apparatus of claim 124, wherein said disc penetrating extensions are of a different height.

128. The apparatus of claim 124, wherein said disc penetrating extensions are of a different length.

129. The apparatus of claim 122, wherein said portion of said disc penetrating extension has a height between said upper and lower surfaces that approximates the height of the normal disc space between the adjacent vertebral bodies.

130. The apparatus of claim 45, further comprising means for penetrating the two adjacent vertebral bodies.

131. The apparatus of claim 130, wherein said penetrating means includes teeth for insertion into the spine.

132. The apparatus of claim 130, wherein said penetrating means includes at least one prong for insertion into the spine.

133. The apparatus of claim 45, further comprising means for limiting the depth of penetration of said disc penetrating extension into the disc space.

134. The apparatus of claim 45, wherein said disc penetrating extension has a tapered leading end to facilitate placement of said disc penetrating extension into the disc space.

135. The apparatus of claim 45 in combination with a bone removal device having a portion sized for passage through said passageway of said guard for forming through said passageway of said guard member an implantation space across the disc space.

136. The apparatus of claim 45 in combination with an implant driver sized in part for passage through said passageway of said guard for passing an implant through said guard member and into the disc space.

137. The apparatus of claim 45 in combination with a spinal distractor sized for passage through said guard member, said spinal distractor having a body and a disc penetrating member extending from said body and into the disc space between the two adjacent vertebral bodies for bearing against the adjacent endplates of the two adjacent vertebral bodies.

138. The apparatus of claim 137, wherein said disc penetrating member has a tapered leading end to facilitate placement of said disc penetrating member into the disc space.

139. The apparatus of claim 45 in combination with a tap for insertion through said guard member for tapping the two adjacent vertebral bodies.

140. The apparatus of claim 45, further comprising an extractor coupler having one end adapted to couple with said guard member and an opposite end adapted to couple with an extraction device.

141. The apparatus of claim 45, wherein said portion of said disc penetrating extension has a height less than the height of said passage.

146. The apparatus of claim 141, wherein said at least one disc penetrating extension has a length that is less than the transverse width of the vertebral bodies, said length being greater than the depth of the spinal disc intermediate the two adjacent vertebral bodies between which said disc penetrating extension is inserted.

142. A spinal instrument assembly, comprising:

a central distractor having

a distractor tip coupled to a shaft, said distractor tip having upper and lower distraction surfaces defining a distraction height therebetween to maintain distraction of a spinal disc space;

a guide sleeve housing having a distal portion and a proximal portion, said guide sleeve housing defining a working channel in which said central distractor is centrally located, wherein said guide sleeve housing is positionable in an operative position with respect to the spinal disc space; and

a guide sleeve having a distal end and a proximal end, said distal end of said guide sleeve removably engageable to said guide sleeve housing.

143. The instrument assembly of claim 142, wherein said central distractor is withdrawable from the spinal disc space and said guide sleeve housing when said guide sleeve housing is in said operative position.

144. The instrument assembly of claim 142, wherein:

said guide sleeve has a first length extending proximally from said guide sleeve housing when engaged thereto;

said guide sleeve housing has a second length extending proximally from the operative site; and

a ratio of said first length to said second length is more than about 2;

1.

145. The instrument assembly of 144, wherein said ratio is less than about 10:

1.