Expansion constraining member adapted for use with an expandable interbody spinal fusion implant and method for use thereof

• US 6,849,093 B2
• Filed: 03/08/2002
• Issued: 02/01/2005
• Est. Priority Date: 03/09/2001
• Status: Active Grant

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Inventors: Michelson, Gary K.
• Primary Examiner(s): Philogene, Pedro
• Application Number:
  US10/094,467
• Publication Number:
  US 20020128712A1
• Time in Patent Office: 1,061 Days
• Field of Search: 623/17.11, 623/17.12, 623/17.13, 623/17.14, 623/17.15, 623/17.16, 606/61, 606/60, 606/63, 606/31, 606/73
• US Class Current: 623/17.15
• CPC Class Codes: A61B 17/8042 the additional component being a cover over the screw head
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• 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 2/442 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 2/4611 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 2002/2835 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 2002/30392 Rotation
• CPC Class Codes: A61F 2002/30397 Limited lateral translation of the rib within a larger groove
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30492 using a locking pin
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30517 using a locking plate
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/30556 for adjusting thickness
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30624 : Hinged joint, e.g. with transverse axle restricting the movement
• CPC Class Codes: A61F 2002/30779 : arcuate
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/3079 : Stepped or enlarged apertures, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/30873 : Threadings machined on non-cylindrical external surfaces
• CPC Class Codes: A61F 2002/30975 : made of two halves
• 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 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures

Abstract

An implant cap is disclosed for preventing the over-expansion of an expandable spinal implant and method for use therewith. An implant cap also is disclosed for moving an expandable spinal implant from a collapsed position to an expanded position with less than one full turn of the implant cap and a method for use therewith. A screw lock is disclosed for locking a bone screw to the trailing end of an expandable spinal implant and a method for use therewith.

Claims

1. An implant cap movable between an insertion position for insertion into an expandable spinal implant and a deployed position for expanding the implant, the implant having upper and lower portions adapted to move apart from one another to contact adjacent upper and lower vertebral bodies, respectively, and an end with an opening configured to cooperatively receive at least a portion of said cap, said cap comprising:

a head having a top surface and a bottom surface opposite said top surface, said heed being configured to cooperatively engage the end of the implant to at least in part cover the opening in the end of the implant; and

a stem projecting from said bottom surface of said head, said stem having a distal end, opposed sides having a width therebetween, and upper and lower surfaces having a height therebetween, the width of said stem being greater than the height of said stem proximate said distal end of said stem when said cap is in the insertion position, said opposed sides being configured to move the upper and lower portions of the implant apart from one another when said cap is rotated from the insertion position to the deployed position.

2. The cap of claim 1, wherein said head is configured to cooperatively engage the end of the implant to completely cover the opening.

3. The cap of claim 1, wherein said opposed sides of said stem are beveled.

4. The cap of claim 1, wherein said opposed sides of said stem are rounded.

5. The cap of claim 4, wherein said opposed sides include a thread adapted for cooperative engagement with the implant.

6. The cap of claim 1, wherein said upper and lower surface of said stem are at least in part tapered towards said distal end of said stem.

7. The cap of claim 1, wherein said stem has a rectangular cross section along at least a portion of the length of said stem.

8. The cap of claim 1, wherein said stem has an arcuate cross section along at least a portion of the length of said stem.

9. The cap of claim 1, wherein said stem has a circular cross section along at least a portion of the length of said stem.

10. The cap of claim 1, wherein said head has a perimeter having at least one arcuate portion.

11. The cap of claim 1, wherein said distal end of said stem is adapted to cooperatively engage one of the upper and lower portions to lock said cap to the implant while the implant is in an expanded position.

12. The cap of claim 11, wherein said distal end of said stem as projections to cooperatively engage the upper and lower portions of the implant.

13. The cap of claim 1, wherein said bottom surface of said head has at least one recess and each of the upper and lower portions proximate the end of the implant has at least one protrusion, each recess being adapted to engage with at least one of the protrusions to prevent the implant from expanding beyond a predetermined height when the implant is expanded.

14. The cap of claim 1, wherein the implant has a plurality of bone screw holes, said bottom surface of said head being configured to cover at least a portion of one of the bone screw holes when said cap is engaged to the implant.

15. The cap of claim 14, wherein said bottom surface of said head is configured to cover a portion of more than one of the bone screw holes when said cap is engaged to the implant.

16. The cap of claim 14, wherein said head is configured to allow the insertion of a bone screw into the implant after said cap is engaged with the implant.

17. The cap of claim 14, wherein said head has a perimeter that is configured to permit the insertion of a bone screw into one of the bone screw holes after said cap is engaged with the implant, said head being movable to cover at least a portion of the bone screw after the bone screw is inserted in one of the bone screw holes.

18. The cap of claim 1, wherein said head is adapted to cooperatively engage a tool for attaching said cap to the implant.

19. The cap of claim 18, wherein said top surface of said head further comprises a marking to indicate the orientation of said cap to the implant once said cap is engaged to the implant.

20. The cap of claim 1, wherein said cap is treated with a bone growth promoting substance.

21. The cap of claim 1, wherein said cap comprises at least one of the following materials:

metal, titanium, plastic, and ceramic appropriate for implantation in the human body.

22. The cap of claim 1, wherein said cap is at least in part resorbable.

23. The cap of claim 1, wherein said cap is formed of a porous material.

24. The cap of claim 1, in combination with a material adapted to inhibit scar formation.

25. The cap of claim 1, in combination with an antimicrobial material.

26. The cap of claim 1, in combination with a spinal implant having upper and lower portions adapted to move apart from one another to contact the vertebral bodies and an end with an opening configured to cooperatively receive at least a portion of said cap.

27. The cap of claim 26, wherein said upper and lower portions a of said implant include at least one opening adapted to communicate with one of the adjacent vertebral bodies, said openings in said upper and lower portions being in communication with one another and adapted for permitting for the growth of bone from adjacent vertebral body to adjacent vertebral body through said implant.

28. The cap of claim 27, wherein said implant includes a hollow interior for holding bone growth promoting material, said hollow interior being in communication with at least one openings in each of said upper an lower portions.

29. The cap of claim 26, wherein said implant is in combination with a bone growth promoting material.

30. The cap of claim 29, wherein said bone growth promoting material is selected from one of bone, bone derived products, demineralized bone matrix, ossifying proteins, bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

31. The cap of claim 26, wherein said implant is treated with bone growth promoting substance.

32. The cap of claim 26, wherein said implant comprises at least one of the following materials:

metal, titanium, plastic, and ceramic appropriate for implantation in the human body.

33. The cap of claim 26, wherein said implant is at lest in part resorbable.

34. The cap of claim 26, wherein said implant is formed of a porous material.

35. The cap of claim 26, wherein said implant is in combination with a material adapted to inhibit scar formation.

36. The cap of claim 26, wherein said implant is in combination with an antimicrobial material.

37. An implant cap for preventing the over-expansion of an expandable spinal implant having upper and lower portions adapted to move apart from one another to contact adjacent upper and lower vertebral bodies, respectively, and an nd having an opening configured to cooperatively receive at least a portion of said cap, each of the upper and lower portions proximate the end of the implant having at least one protrusion, said cap comprising:

a head configured to cooperatively engage the end of the implant to at least in part cover the opening, said head having a top surface and a bottom surface opposite said top surface, said bottom surface having a recess adapted to cooperatively receive the protrusions to prevent the implant from expanding beyond a predetermined height by limiting movement of the protrusions apart from one another; and

a stem projecting from said bottom surface of said head, said stem being adapted for insertion into the opening of the implant.

38. The cap of claim 37, wherein said head is configured to cooperatively engage the end of the implant to completely cover the opening.

39. The cap of claim 37, wherein the implant has a plurality of bone screw holes, said bottom surface of said head being configured to cover at least a portion of one of the bone screw holes when said cap is engaged to the implant.

40. The cap of claim 39, wherein said bottom surface of said head is configured to cover a portion of more than one of the bone screw holes when said cap is engaged to the implant.

41. The cap of claim 39, wherein said head is configured to allow the insertion of a bone screw into the implant after said cap is engaged with the implant.

42. The cap of claim 39, wherein said head has a perimeter that is configured to permit the insertion of a bone screw into one of the bone screw holes after said cap is engaged with the implant, said head being movable to cover at least a portion of the bone screw after the bone screw is inserted in one of the bone screw holes.

43. The cap of claim 37, wherein said cap is treated with a bone growth promoting substance.

44. The cap of claim 37, wherein said cap comprises at least one of the following materials:

metal, titanium, plastic, and ceramic appropriate for implantation in the human body.

45. The cap of claim 37, wherein said cap is at least in part resorbable.

46. The cap of claim 37, wherein said cap is formed of a porous material.

47. The cap of claim 37, in combination with a material adapted to inhibit scar formation.

48. The cap of claim 37, in combination with an antimicrobial material.

49. The cap of claim 37, in combination with a spinal implant having upper and lower portions adapted to move apart from one another to contact the vertebral bodies and an end with an opening configured to cooperatively receive at least a portion of said cap.

50. The cap of claim 49, wherein said upper and lower portions of said implant include at least one opening adapted to communicate with one of the adjacent vertebral bodies, said openings in said upper and lower portions being in communication with one another and adapted for permitting for the growth of bone from adjacent vertebral body to adjacent vertebral body through said implant.

51. The cap of claim 50, wherein said implant includes a hollow interior for holding bone growth promoting material, said hollow interior being in communication with at least one openings in each of said upper an lower portions.

52. The cap of claim 49, wherein said implant is in combination with a bone growth promoting material.

53. The cap of claim 52, wherein said bone growth promoting material is selected from one of bone, bone derived products, demineralized bone matrix, ossifying proteins, bone morphogenetic protein, hydroxyapatite, an genes coding for the production of bone.

54. The cap of claim 49, wherein said implant is treated with bone growth promoting substance.

55. The cap of claim 49, wherein said implant comprises at least one of the following materials:

metal, titanium, plastic, and ceramic appropriate for implantation in the human body.

56. The cap of claim 49, wherein said implant is at least in part resorbable.

57. The cap of claim 49, wherein said implant is formed of a porous material.

58. The cap of claim 49, wherein said implant is in combination with a material adapted to inhibit scar formation.

59. The cap of claim 49, wherein said implant is in combination with an antimicrobial material.

60. An implant cap for preventing the over-expansion of an expandable spinal implant having upper and lower portions adapted to move apart from one another to contact adjacent upper and lower vertebral bodies, respectively, and an end having an opening configured to cooperatively receive at least a portion of said cap, each of the upper and lower portions proximate the end of the implant having a recess, said cap comprising:

a head configured to cooperatively engage the end of the implant to at least in part cover the opening, said head having a top surface and a bottom surface opposite said top surface, said bottom surface having at least one protrusion adapted to cooperatively engage the recesses in the end of the implant to prevent the implant from expanding beyond a predetermined height by limiting movement of the upper and lower portions relative to one another; and

a stem projecting from said bottom surface of said head, said stem being adapted for insertion into the opening of the implant.

61. The cap of claim 60, wherein said head is configured to cooperatively engage the end of the implant to completely cover the opening.

62. The cap of claim 60, wherein the implant has a plurality of bone screw holes, said bottom surface of said head being configured to cover at least a portion of one of the bone screw holes when said cap is engaged to the implant.

63. The cap of claim 62, wherein said bottom surface of said head is configured to cover a portion of more than one of the bone screw holes when said cap is engaged to the implant.

64. The cap of claim 62, wherein said head is configured to allow the insertion of a bone screw into the implant after said cap is engaged with the implant.

65. The cap of claim 62, wherein said head has a perimeter that is configured to permit the insertion of a bone screw into one of the bone screw holes after said cap is engaged with the implant, said head being movable to cover at least a portion of the bone screw after the bone screw is inserted in one of the bone screw holes.

66. The cap of claim 60, wherein said cap is treated with a bone growth promoting substance.

67. The cap of claim 60, wherein said cap comprises at least one of the following materials:

metal, titanium, plastic, and ceramic appropriate for implantation in the human body.

68. The cap of claim 60, wherein said cap is at least in part resorbable.

69. The cap of claim 60, wherein said cap is formed of a porous material.

70. The cap of claim 60, in combination with a material adapted to inhibit scar formation.

71. The cap of claim 60, in combination with an antimicrobial material.

72. The cap of claim 60, in combination with a spinal implant having upper and lower portions adapted to move apart from one another to contact the vertebral bodies and an end with an opening configured to cooperatively receive at least a portion of said cap.

73. The cap of claim 72, wherein said upper and lower portions of said implant include at least one opening adapted to communicate with one of the adjacent vertebral bodies, said openings in said upper and lower portions being in communication with one another and adapted for permitting for the growth of bone from adjacent vertebral body to adjacent vertebral body through said implant.

74. The cap of claim 73, wherein implant includes a hollow interior for holding bone growth promoting material, said hollow interior being communication with at least one openings in each of said upper an lower portions.

75. The cap of claim 72, wherein said implant is in combination with a bone growth promoting material.

76. The cap of claim 75, wherein said bone growth promoting material is selected from one of bone, bone derived products, demineralized bone matrix, ossifying proteins, bone morphogenetic protein, hydroxyapatite, an genes coding for the production of bone.

77. The cap of claim 72, wherein said implant is treated with bone growth promoting substance.

78. The cap of claim 72, wherein said implant comprises at least one of the following materials:

metal, titanium, plastic, and ceramic appropriate for implantation in the human body.

79. The cap of claim 72, wherein said implant is at least in part resorbable.

80. The cap of claim 72, wherein said implant is formed of a porous material.

81. The cap of claim 72, wherein said implant is in combination with a material adapted to inhibit scar formation.

82. The cap of claim 72, wherein said implant is in combination with an antimicrobial material.

83. A screw lock for locking a plurality of bone screws to a spinal implant, the implant having upper and lower portions adapted to move apart from one another to contact adjacent upper and lower vertebral bodies, respectively, the implant having a trailing end with a plurality of bone screw holes and an opening adapted to cooperatively receive at least a portion of said lock, said lock comprising:

a head having a top surface and a bottom surface opposite said top surface, said bottom surface being adapted to cover at least a portion of the bone screw holes when the implant is in an expanded position; and

a stem projecting from said bottom surface of said head, said stem being adapted for insertion into the opening of the trailing end of the implant to move apart the upper and lower portions to an increased height of the implant upon rotation of said stem from an insertion position to a deployed position, said stem having a non-circular cross section transverse to the longitudinal axis of said stem.

84. The lock of claim 83, wherein said head is configured to cooperatively engage the trailing end of implant to completely cover the opening.

85. The lock of claim 83, wherein said stem has a rectangular cross section along at least a portion of the length of said stem.

86. The lock of claim 83, wherein said stem has a distal end adapted to cooperatively engage one of the upper and lower portions to lock said lock to the implant while the implant is in an expanded position.

87. The lock of claim 86, wherein said distal end of said stem has projections to cooperatively engage the upper and lower portions of the implant.

88. The lock of claim 83, wherein said bottom surface of said head has at least one recess and each of the upper and lower portions proximate the end of the implant has at least one protrusion, each recess being adapted to engage with at least one of the protrusions to prevent the implant from expanding beyond a predetermined height when the implant is expanded.

89. The lock of claim 83, wherein said lock is treated with a bone growth promoting substance.

90. The lock of claim 83, wherein said lock comprises at least one of the following materials:

metal, titanium, plastic, and ceramic appropriate for implantation in the human body.

91. The lock of claim 83, wherein said lock is at least in part resorbable.

92. The lock of claim 83, wherein said lock is formed of a porous material.

93. The lock of claim 83, in combination with a material adapted to inhibit scar formation.

94. The lock of claim 83, in combination with an antimicrobial material.

95. The lock of claim 83, in combination with a spinal implant having upper and lower portions adapted to move apart from one another contact the vertebral bodies and a trailing end with an opening configured to cooperatively receive at least a portion of said lock.

96. The lock of claim 95, wherein said upper and lower portion of said implant include at least one opening adapted to communicate with one of the adjacent vertebral bodies, said openings in said upper and lower portions being in communication with one another and adapted for permitting for the growth of bone from adjacent vertebral body to adjacent vertebral body through said implant.

97. The lock of claim 96, wherein said implant includes a hollow interior for holding bone growth promoting material, said hollow interior being in communication with at least one openings in each of said upper a lower portions.

98. The lock of claim 95, wherein said implant is in combination with a bone growth promoting material.

99. The lock of claim 98, wherein said bone growth promotion material is selected from one of bone, bone derived products, demineralized bone matrix, ossifying proteins, bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

100. The lock of claim 95, wherein said implant is treated with a bone growth promoting substance.

101. The lock of claim 95, wherein said implant comprises at least one of the following materials:

metal, titanium, plastic, and ceramic appropriate for implantation in the human body.

102. The lock of claim 95, wherein said implant is at least in part resorbable.

103. The lock of claim 95, wherein said implant is formed of a porous material.

104. The lock of claim 95, wherein said implant is in combination with a material adapted to inhibit scar formation.

105. The lock of claim 95, wherein said implant is in combination with an antimicrobial material.

106. A method for engaging an end cap having a stem to an expandable spinal implant having an end, the method comprising the steps of:

inserting the stem of the end cap into the end of the implant;

rotating the stem of the end cap to expand the height of the implant; and

using a portion of the end cap to prevent the implant from expanding beyond a predetermined height.

107. The method of claim 106, wherein the step of rotating the stem includes rotating the stem less than one full turn to expand the implant to an increased maximum implant height.

108. The method of claim 106, wherein the step of rotating the stem includes rotating the stem approximately 90 degrees.

109. The method of claim 106, wherein the step of rotating the stem includes rotating a stem having no threads.

110. The method of claim 106, wherein the step of using a portion of the end cap includes receiving into at least one recess on the end cap at least one protrusion on the end of the implant.

111. The method of claim 106, wherein the step of using a portion of the end cap includes engaging at least one protrusion on the end cap into at least one recess on the end of the implant.

112. The method of claim 106, further comprising the step of locking the cap to the implant.

113. The method of claim 106, further comprising the step of locking the implant in an expanded position.

114. The method of claim 106, wherein the implant has a plurality of bone screw holes, further comprising the step of covering at least a portion of the bone screw holes with at least a portion of the end cap.

115. The method of claim 114, further comprising the step of inserting at least one bone screw in the implant after the stem of the end cap inserted into the end of the implant.

116. The method of claim 106, wherein the end of the implant includes an opening leading to an interior hollow having a bone growth promoting material therein, further comprising the step of covering at least a portion of the opening with the end cap.