Apparatus and method for the delivery of electrical current for interbody spinal arthrodesis

• US 6,605,089 B1
• Filed: 09/23/1999
• Issued: 08/12/2003
• Est. Priority Date: 05/27/1994
• Status: Expired due to Fees

• Current Assignee: Gary K. Michelson
• Original Assignee: Gary K. Michelson
• Inventors: Michelson, Gary Karlin
• Primary Examiner(s): Brown, Michael A.
• Application Number:
  US09/404,396
• Time in Patent Office: 1,419 Days
• Field of Search: 606/60, 606/61, 623/17.16, 623/17.11, 607/50, 607/51
• US Class Current: 606/32
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/7074 Tools specially adapted for spinal fixation operations other than for bone removal or filler handling A61B17/7062, A61B17/808, A61B17/8858 take precedence; for spinal image producing devices A61B90/36, A61B34/20; markers A61B90/39
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• 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 2/44 for the spine, e.g. vertebrae, spinal discs
• 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 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• 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 2002/2821 Bone stimulation by electromagnetic fields or electric current for enhancing ossification
• 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 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/30179 : X-shaped
• CPC Class Codes: A61F 2002/30235 : tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30261 : parallelepipedal
• CPC Class Codes: A61F 2002/3037 : Translation along the common longitudinal axis, e.g. piston
• CPC Class Codes: A61F 2002/30398 : Sliding
• CPC Class Codes: A61F 2002/30405 : made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30433 : using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30507 : using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30556 : for adjusting thickness
• CPC Class Codes: A61F 2002/30579 : with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30599 : stackable
• 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 2002/30789 : perpendicular with respect to each other
• CPC Class Codes: A61F 2002/30797 : internally-threaded
• CPC Class Codes: A61F 2002/30836 : knurled
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30843 : Pyramidally-shaped
• CPC Class Codes: A61F 2002/30845 : with cutting edges
• 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 2002/3092 : having an open-celled or open-pored structure
• 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 2002/4485 : comprising three or more 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 2002/4681 : 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 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• 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 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0026 : trapezoidal
• CPC Class Codes: A61F 2230/0058 : X-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• 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 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
• CPC Class Codes: A61N 1/0551 : Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/205 : for promoting a biological process

Abstract

An electrical bone growth promotion apparatus and method for the delivery of electrical current to an implant surgically implanted within the intervertebral space between two adjacent vertebrae of the spine to promote bone growth and the fusion process to areas adjacent to the implant is disclosed. The apparatus of the present invention comprises a self contained implant having a surgically implantable, renewable power supply and related control circuitry for delivering electrical current directly to the implant and thus directly to the area in which the promotion of bone growth is desired. The desired areas of bone growth promotion may be controlled by conducting negative charge only to the desired location of bone growth promotion.

Claims

1. A device for placement into and between at least two adjacent bone masses to promote bone growth therebetween, said device comprising:

an implant having opposed first and second surfaces for placement between and in contact with the adjacent bone masses, a mid-longitudinal axis, and a hollow chamber between said first and second surfaces, said hollow chamber being adapted to hold bone growth promoting material, said hollow chamber being along at least a portion of the mid-longitudinal axis of said implant, each of said first and second surfaces having at least one opening in communication with said hollow chamber into which bone from the adjacent bone masses grows; and

an energizer for energizing said implant, said energizer being sized and configured to promote bone growth from adjacent bone mass to adjacent bone mass through said first and second surfaces and through at least a portion of said hollow chamber at the mid-longitudinal axis.

2. The device of claim 1, wherein said first and second surfaces form walls surrounding said hollow chamber.

3. The device of claim 1, further comprising an access opening-for accessing said hollow chamber.

4. The device of claim 3, further including a cap for closing said access opening of said hollow chamber.

5. The device of claim 4, herein said energizer attaches to said cap.

6. The device of claim 1, wherein said implant has a coil wrapped around said implant, said coil being electrically conductive.

7. The device of claim 6, wherein at least a portion of said coil is in the form of an external thread on at least a portion of said first and second surfaces of said implant.

8. The device of claim 7, wherein said external thread is energized by said energizer.

9. The device of claim 7, wherein said external thread conducts electromagnetic energy to said interior space.

10. The device of claim 1, wherein said implant further includes a passage between at least two of said openings through said implant such that said passage communicates with each of the adjacent bone masses to be joined, and a conductive coil disposed about said passage and coupled to said energizer.

11. The device of claim 10, wherein said coil and said passage are coaxial.

12. The device of claim 10, wherein said interior space is in communication with said passage and said coil.

13. The device of claim 1, wherein said energizer is contained within said implant.

14. The device of claim 1, wherein said energizer is a power supply delivering an electric charge.

15. The device of claim 14, wherein said implant has a first portion that is electrically conductive for delivering said electrical charge to at least a portion of the adjacent bone masses and said energizer delivers negative electrical charge to said first portion of said implant.

16. The device of claim 15, wherein said implant has a second portion that is electrically conductive for delivering said positive electrical charge to at least a portion of the adjacent bone masses and said energizer delivers positive electrical charge to said second portion of said implant.

17. The device of claim 14, further comprising a controller for controlling the delivery of said electric charge.

18. The device of claim 17, wherein said controller is contained within said implant.

19. The device of claim 17, wherein said controller includes one of a wave form generator and a voltage generator.

20. The device of claim 17, wherein said controller delivers intermittent pulses of current.

21. The device of claim 17, wherein said controller provides for the delivery of one of an alternating current, a direct current, and a sinusoidal current.

22. The device of claim 17, wherein said controller generates electrical noise.

23. The device of claim 1, wherein said energizer comprises a surgically implantable battery.

24. The device of claim 23, wherein said battery is rechargeable.

25. The device of claim 1, wherein said energizer includes one of an electromagnetic wave generator, an electromagnetic energy generator, and a magnetic field generator.

26. The device of claim 1, wherein said energizer comprises an electromagnetic field generator positioned external to the patient'"'"'s body inductively coupled to said implant.

27. The device of claim 1, wherein said implant is energized with and emits an electromagnetic field.

28. The device of claim 1, wherein said first and second surfaces of said implant are at least in part arcuate.

29. The device of claim 28, wherein said implant is generally cylindrical.

30. The device of claim 1, wherein said first and second surfaces of said implant are at least in part planar.

31. The device of claim 1, wherein said implant fits entirely between the adjacent bone masses.

32. The device of claim 1, wherein said implant is formed of a material which is stronger than the adjacent bone masses.

33. The device of claim 1, wherein said implant comprises a material other than bone.

34. The device of claim 1, wherein said implant comprises bone.

35. The device of claim 34, wherein is said bone includes cortical bone.

36. The device of claim 1, wherein said implant comprises bone growth promoting material.

37. The device of claim 36, wherein said bone growth promoting material is at least in part bone.

38. The device of claim 36, wherein said bone growth promoting material is a material other than bone.

39. The device of claim 36, wherein said bone growth promoting material is selected from one of bone morphogenetic protein and hydroxyapatite.

40. The device of claim 1, wherein said implant is coated with a bone growth promoting substance.

41. The device of claim 1, in combination with bone growth promoting material.

42. The combination of claim 41, wherein said bone growth promoting material is at least in part bone.

43. The combination of claim 41, wherein said bone growth promoting material is a material other than bone.

44. The combination of claim 41, wherein said bone growth promoting material includes at least one of bone morphogenetic protein and hydroxyapatite.

45. The device of claim 1, wherein at least one of said openings of said implant contains fusion promoting materials for promoting bone ingrowth in continuity through said implant from one of the adjacent bone masses to the other of the adjacent bone masses.

46. The device of claim 1, wherein said implant comprises an implant quality metal.

47. The device of claim 46, wherein said metal is an ASTM material suitable for use as a spinal fusion implant.

48. The device of claim 46, wherein said metal includes titanium.

49. The device of claim 1, wherein said implant is formed of a porous material.

50. The device of claim 1, wherein at least a portion of said first and second surfaces include surface roughenings.

51. The device of claim 50, wherein said surface roughenings include at least one of a thread, knurl, and raised protrusion.

52. The device of claim 1, wherein said implant comprises a material that is a source of osteogenesis.

53. The device of claim 1, wherein said implant is in combination with a material that intrinsically participates in the growth of bone from one of the adjacent vertebrae to the other of the adjacent vertebrae.

54. The device of claim 1, wherein said implant is an interbody spinal fusion implant.

55. The device of claim 1, wherein the adjacent bone masses are vertebral bodies.

56. The device of claim 1, wherein said implant is for fusion of a joint in the body.

57. The device of claim 1, wherein the adjacent bone masses are broken portions of the same bone.

58. The device of claim 1, wherein said implant is more than 75% hollow by volume.

59. The device of claim 1, wherein said implant has a maximum internal dimension and a maximum external dimension along a cross section transverse to the mid-longitudinal axis of said implant, said maximum internal dimension being greater than one half said maximum external dimension.

60. The device of claim 1, wherein said hollow chamber is along more than one half of the mid-longitudinal axis of said implant between a leading end of said implant and a trailing end of said implant.

61. The device of claim 1, in combination with a spinal insert.

62. The combination of claim 61, wherein said spinal insert is a bone plug.

63. The device of claim 1, in combination with an orthopedic device for use with said implant.

64. The combination of claim 63, wherein said orthopedic device is a driver instrument.

65. The combination of claim 63, wherein said orthopedic device is an obdurator for compacting bone material.

66. The device of claim 1, in combination with a power supply for energizing said implant.

67. The combination of claim 66, wherein said power supply is a generator.

68. The combination of claim 66, wherein said power supply is a battery.

69. The combination of claim 66, wherein said power supply is an electronic transmitter.

95. The device of claim 67 wherein said implant has a coil wrapped around said implant, said coil being electrically conductive.

97. The device of claim 95, wherein said external thread is energized by said energizer.

70. A device for placement into and between at least two adjacent bone masses to promote bone growth therebetween, said device comprising:

an energizer; and

an implant having opposed first and second surfaces for placement between and in contact with the adjacent bone masses, a mid-longitudinal axis, and a hollow chamber between said first and second surfaces, each of said first and second surfaces having at least one opening in communication with said hollow chamber into which bone from the adjacent bone masses grows, said energizer being at least in part within said hollow chamber and being sized and configured to promote bone growth from adjacent bone mass to adjacent bone mass through said first and second surfaces and through at least a portion of said hollow chamber at the mid-longitudinal axis.

71. The device of claim 70, wherein said implant material comprises an implant quality metal.

72. The device of claim 71, wherein said metal is an ASTM material suitable for use as a spinal fusion implant.

73. The device of claim 71, wherein said metal includes titanium.

74. The device of claim 70, wherein said implant material is stronger than the adjacent bone masses.

75. The device of claim 70, wherein said implant further comprises bone.

76. The device of claim 75, wherein is said bone includes cortical bone.

77. The device of claim 70, wherein said implant further comprises bone growth promoting material.

78. The device of claim 77, wherein said bone growth promoting material is at least in part bone.

79. The device of claim 77, wherein said bone growth promoting material is a material other than bone.

80. The device of claim 77, wherein said bone growth promoting material is selected from one of bone morphogenetic protein and hydroxyapatite.

81. The device of claim 70, wherein said implant is coated with a bone growth promoting substance.

82. The device of claim 70, in combination with bone growth promoting material.

83. The combination of claim 82, wherein said bone growth promoting material is at least in part bone.

84. The combination of claim 82, wherein said bone growth promoting material is a material other than bone.

85. The combination of claim 82, wherein said bone growth promoting material includes at least one of bone morphogenetic protein and hydroxyapatite.

86. The device of claim 70, wherein at least one of said openings of said implant contains fusion promoting materials for promoting bone ingrowth in continuity through said implant from one of the adjacent bone masses to the other of the adjacent bone masses.

87. The device of claim 70, in combination with bone growth promoting material contained within said hollow chamber.

88. The combination of claim 87, wherein said first and second surfaces form walls surrounding said hollow chamber.

89. The device of claim 87, wherein said implant further includes a passage between at least two of said openings through said implant such that said passage communicates with each of the adjacent bone masses to be joined, and a conductive coil disposed about said passage and coupled to said energizer.

90. The device of claim 89, wherein said coil and said passage are coaxial.

91. The device of claim 90, wherein said interior space is in communication with said passage and said coil.

92. The device of claim 70, further comprising an access opening for accessing said hollow chamber.

93. The device of claim 91, further including a cap for closing said access opening of said hollow chamber.

94. The device of claim 92, wherein said energizer attaches to said cap.

96. The device of claim 94, wherein at least a portion of said coil is in the form of an external thread on at least a portion of said first and second surfaces of said implant.

98. The device of claim 96, wherein said external thread conducts electromagnectic energy to said interior space.

99. The device of claim 70, wherein said energizer is a power supply delivering an electric charge.

100. The device of claim 99, wherein said implant has a first portion that is electrically conductive for delivering said electrical charge to at least a portion of the adjacent bone masses and said energizer delivers negative electrical charge to said portion of said implant.

101. The device of claim 100, wherein said implant has a second portion that is electrically conductive for delivering said positive electrical charge to at least a portion of the adjacent bone masses and said energizer delivers positive electrical charge to said second portion of said implant.

102. The device of claim 99, further comprising a controller for controlling the delivery of said electric charge.

103. The device of claim 102, wherein said controller is contained within said implant.

104. The device of claim 102, wherein said controller includes one of a wave form generator and a voltage generator.

105. The device of claim 102, wherein said controller delivers intermittent pulses of current.

106. The device of claim 102, wherein said controller provides for the delivery of one of an alternating current, a direct current, and a sinusoidal current.

107. The device of claim 102, wherein said controller generates electrical noise.

108. The device of claim 70, wherein said energizer comprises a surgically implantable battery.

109. The device of claim 108, wherein said battery is rechargeable.

110. The device of claim 70, wherein said energizer includes one of an electromagnetic wave generator, an electromagnetic energy generator, and a magnetic field generator.

111. The device of claim 70, wherein said energizer comprises an electromagnetic field generator positioned external to the patient'"'"'s body inductively coupled to said implant.

112. The device of claim 70, wherein said implant is energized with and emits an electromagnetic field.

113. The device of claim 70, wherein said first and second surfaces of said implant are at least in part arcuate.

114. The device of claim 113, wherein said implant is generally cylindrical.

115. The device of claim 70, wherein said first and second surfaces of said implant are at least in part planar.

116. The device of claim 70, wherein said implant fits entirely between the adjacent bone masses.

117. The device of claim 70, wherein said implant is an interbody spinal fusion implant.

118. The device of claim 70, wherein said implant is for fusion of a joint in the body.

119. The device of claim 70, wherein said adjacent bone masses are broken portions of the same bone.

120. The device of claim 70, wherein said implant comprises a material that is a source of osteogenesis.

121. The device of claim 70, wherein at least a portion of said first and second surfaces include surface roughenings.

122. The device of claim 121, wherein said surface roughenings include at least one of a thread, knurl, and raised protrusion.

123. The device of claim 70, wherein said implant is more than 75% hollow by volume.

124. The device of claim 70, wherein said implant has a maximum internal dimension and a maximum external dimension along a cross section transverse to the mid-longitudinal axis of said implant, said maximum internal dimension being greater than one half said maximum external dimension.

125. The device of claim 70, in combination with a spinal insert.

126. The combination of claim 125, wherein said spinal insert is a bone plug.

127. The device of claim 70, in combination with an orthopedic device for use with said implant.

128. The combination of claim 127, wherein said orthopedic device is a driver instrument.

129. The combination of claim 127, wherein said orthopedic device is an obdurator for compacting bone material.

130. The device of claim 70, in combination with a power supply for energizing said implant.

131. The combination of claim 130, wherein said power supply is a generator.

132. The combination of claim 130, wherein said power supply is a battery.

133. The combination of claim 130, wherein said power supply is an electronic transmitter.