Electrosurgical apparatus and methods for treating joint tissue

• US 20030225403A1
• Filed: 02/13/2003
• Published: 12/04/2003
• Est. Priority Date: 06/09/2000
• Status: Active Grant

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Woloszko, Jean, Ormsby, Theodore C., Davison, Paul O.
• Granted Patent: US 6,991,631 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• CPC Class Codes: A61B 18/148 having a short, rigid shaft for accessing the inner body transcutaneously, e.g. for neurosurgery or arthroscopy
• CPC Class Codes: A61B 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/00327 Ear, nose or throat
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/1497 Electrodes covering only part of the probe circumference
• CPC Class Codes: A61B 2218/007 Aspiration

Abstract

Electrosurgical methods, systems, and apparatus for the controlled ablation of tissue from a target site, such as a synovial joint, of a patient. An electrosurgical probe of the invention includes a shaft, and a working end having an electrode array comprising an outer circular arrangement of active electrode terminals and an inner circular arrangement of active electrode terminals. The electrode array is adapted for the controlled ablation of hard tissue, such as meniscus tissue. The working end of the probe is curved to facilitate access to both medial meniscus and lateral meniscus from a portal of 1 cm. or less.

Claims

1. An electrosurgical probe for ablating cartilage tissue from a synovial joint, comprising:

a shaft having a shaft distal end and a shaft proximal end;

an electrically insulating electrode support affixed to the shaft distal end; and

an electrode array disposed on the electrode support, the electrode array comprising a first circular arrangement of active electrode terminals and a second circular arrangement of active electrode terminals, wherein the second circular arrangement of active electrode terminals is concentric with the first circular arrangement of active electrode terminals.

2. The electrosurgical probe of claim 1, wherein the probe includes a working end, the working end of the probe curved at an angle in the range of from about 25°

to 35°

with respect to the longitudinal axis of the shaft, and wherein the curved working end is adapted for accessing all regions of a medial meniscus and a lateral meniscus of a knee joint.

3. The electrosurgical probe of claim 1, wherein the shaft has a length in the range of from about 4.5 to 5.5 inches.

4. The electrosurgical probe of claim 1, further comprising an aspiration unit adapted for removing materials from a working end of the probe.

5. The electrosurgical probe of claim 4, wherein the aspiration unit comprises an aspiration lumen and an aspiration tube, the aspiration tube coupled to a proximal end of the aspiration lumen.

6. The electrosurgical probe of claim 5, wherein the electrode support includes a distal tissue treatment surface, the electrode support having a void therethrough, and the void defining an aspiration port in the tissue treatment surface.

7. The electrosurgical probe of claim 6, further comprising a digestion electrode adapted for digesting fragments of resected tissue.

8. The electrosurgical probe of claim 7, wherein the digestion electrode is arranged substantially parallel to the tissue treatment surface.

9. The electrosurgical probe of claim 7, wherein the digestion electrode is arranged substantially orthogonal to each of the active electrode terminals.

10. The electrosurgical probe of claim 7, wherein the digestion electrode comprises a tungsten wire.

11. The electrosurgical probe of claim 7, wherein the digestion electrode has a diameter in the range of from about 0.006 inches to 0.012 inches.

12. The electrosurgical probe of claim 7, wherein the digestion electrode spans the aspiration port.

13. The electrosurgical probe of claim 7, wherein the digestion electrode is substantially flush with the tissue treatment surface.

14. The electrosurgical probe of claim 7, wherein the digestion electrode comprises a wire having a free end terminating within the electrode support.

15. The electrosurgical probe of claim 7, wherein the digestion electrode lies within the first circular arrangement of the active electrode terminals.

16. The electrosurgical probe of claim 6, wherein the aspiration lumen is coupled to the void of the electrode support.

17. The electrosurgical probe of claim 5, wherein the aspiration lumen comprises polyetheretherketone (PEEK) tubing.

18. The electrosurgical probe of claim 5, wherein the aspiration tube comprises polyvinylchloride (PVC) tubing.

19. The electrosurgical probe of claim 5, further comprising a handle affixed to the shaft proximal end, wherein a distal end of the aspiration tube is affixed to the handle.

20. The electrosurgical probe of claim 5, wherein the aspiration unit further comprises a suction flow control unit coupled within the aspiration tube.

21. The electrosurgical probe of claim 20, wherein the suction flow control unit is adapted for adjusting the flow of an aspiration stream, the aspiration stream flowing through the aspiration unit.

22. The electrosurgical probe of claim 21, wherein the suction flow control unit is further adapted for inactivating the aspiration unit.

23. The electrosurgical probe of claim 20, wherein the suction flow control unit comprises a roller clamp.

24. The electrosurgical probe of claim 20, wherein the suction flow control unit is disposed on a suction control housing.

25. The electrosurgical probe of claim 24, wherein the suction control housing is adapted for coupling to a vacuum source.

26. The electrosurgical probe of claim 1, wherein each of the active electrode terminals has a length in the range of from about 0.010 to 0.050 inches.

27. The electrosurgical probe of claim 1, wherein the electrode array comprises at least 10 of the active electrode terminals.

28. The electrosurgical probe of claim 1, wherein the electrode array comprises at least 20 of the active electrode terminals.

29. The electrosurgical probe of claim 1, wherein the electrode array comprises from about 20 to 25 of the active electrode terminals.

30. The electrosurgical probe of claim 1, wherein the active electrode terminals are spaced apart by an inter-electrode distance in the range of from about 0.002 inches to 0.008 inches.

31. The electrosurgical probe of claim 1, wherein the active electrode terminals are spaced apart by an inter-electrode distance of about 0.004 inches.

32. The electrosurgical probe of claim 1, wherein the first circular arrangement comprises an outer ring of the active electrode terminals.

33. The electrosurgical probe of claim 32, wherein the outer ring comprises from about 10 to 20 of the active electrode terminals.

34. The electrosurgical probe of claim 32, wherein the outer ring comprises about 14 of the active electrode terminals.

35. The electrosurgical probe of claim 32, wherein the second circular arrangement comprises an inner ring of the active electrode terminals.

36. The electrosurgical probe of claim 35, wherein the inner ring comprises from about 5 to 10 of the active electrode terminals.

37. The electrosurgical probe of claim 35, wherein the inner ring comprises from 7 to 8 of the active electrode terminals.

38. The electrosurgical probe of claim 35, wherein the ratio of the number of active electrode terminals in the outer ring to the number of active electrode terminals in the inner ring is in the range of from about 1.5:

1 to about 2.5;

1.

39. The electrosurgical probe of claim 35, wherein the ratio of the number of active electrode terminals in the outer ring to the number of active electrode terminals in the inner ring is in the range of from about 14:

9 to about 14;

6.

40. The electrosurgical probe of claim 1, wherein the electrode support includes a distal tissue treatment surface, and the active electrode terminals are arranged substantially orthogonal to the tissue treatment surface.

41. The electrosurgical probe of claim 40, wherein the tissue treatment surface is spaced distally from the shaft distal end by a distance in the range of from about 0.025 inches to 0.075 inches.

42. The electrosurgical probe of claim 1, wherein each of the plurality of active electrode terminals comprises a material selected from the group consisting of tungsten, stainless steel, platinum, titanium, molybdenum, palladium, iridium, nickel, aluminum, gold, copper, and their alloys.

43. The electrosurgical probe of claim 1, wherein each active electrode terminal comprises a tungsten wire.

44. The electrosurgical probe of claim 1, wherein each active electrode terminal has a diameter in the range of from about 0.006 inches to 0.012 inches.

45. The electrosurgical probe of claim 1, further comprising a return electrode disposed proximal to the electrode support.

46. The electrosurgical probe of claim 45, further comprising an electrically insulating sleeve ensheathing a proximal portion of the shaft.

47. The electrosurgical probe of claim 46, wherein the sleeve comprises a heat-shrink plastic tube.

48. The electrosurgical probe of claim 46, wherein the sleeve comprises a polyester.

49. The electrosurgical probe of claim 46, wherein the shaft comprises a metal tube, and an exposed, distal portion of the shaft defines the return electrode.

50. The electrosurgical probe of claim 49, wherein the return electrode has a length in the range of from about 2 mm to 5 mm.

51. The electrosurgical probe of claim 1, wherein the electrode support includes a plurality of electrode ports, each of the plurality of electrode ports adapted for accommodating one of the active electrode terminals.

52. The electrosurgical probe of claim 1, wherein the electrode support comprises a silicone rubber or a ceramic.

53. The electrosurgical probe of claim 1, wherein the tissue treatment surface is substantially planar.

54. The electrosurgical probe of claim 1, wherein the electrode support is substantially cylindrical.

55. The electrosurgical probe of claim 1, wherein the electrode support has a central void, the void defining an aspiration port in the tissue treatment surface.

56. The electrosurgical probe of claim 55, wherein the aspiration port is concentric with both the first circular arrangement of the active electrode terminals and the second circular arrangement of the active electrode terminals.

57. The electrosurgical probe of claim 1, wherein the electrode support is a silicone rubber extrusion product.

58. An electrosurgical probe for removing tissue from a synovial joint, comprising:

a shaft having a shaft distal end and a shaft proximal end;

an electrically insulating electrode support affixed to the shaft distal end;

an electrode array disposed on the electrode support, the electrode array comprising a plurality of active electrode terminals, the electrode support and the plurality of active electrode terminals defining an electrode assembly, the shaft distal end and the electrode assembly defining a working end portion of the probe, wherein the working end portion is curved, and the plurality of active electrode terminals are arranged at an angle in the range of from about 25°

to 35°

with respect to the longitudinal axis of the shaft.

59. The electrosurgical probe of claim 58, wherein the electrode array comprises an outer ring of the plurality of active electrode terminals and an inner ring of the plurality of active electrode terminals, wherein the outer ring comprises from about 10 to 20 of the plurality of active electrode terminals, and the inner ring comprises from about 5 to 10 of the plurality of active electrode terminals, and wherein the inner ring is concentric with the outer ring.

60. An electrosurgical probe for ablating tissue from a target site, comprising:

a working end portion including an electrode assembly, the electrode assembly comprising an electrically insulating electrode support and a plurality of active electrode terminals disposed on the electrode support; and

a shaft having a shaft distal end, the electrode support affixed to the shaft distal end, wherein the working end portion is curved and the plurality of active electrode terminals are arranged at an angle in the range of from about 25°

to 35°

with respect to the longitudinal axis of the probe.

61. The electrosurgical probe of claim 60, wherein the electrode support includes a tissue treatment surface, the plurality of active electrode terminals extending from the tissue treatment surface, wherein the plurality of active electrode terminals are substantially orthogonal to the tissue treatment surface.

62. The electrosurgical probe of claim 60, wherein the plurality of active electrode terminals are arranged on the electrode support in the form of an outer ring of the plurality of active electrode terminals and an inner ring of the plurality of active electrode terminals, wherein the inner ring is concentric with the outer ring.

63. An electrosurgical system, comprising:

a probe including a shaft having a shaft distal end, the probe further including an electrode assembly disposed at the shaft distal end, the electrode assembly comprising a plurality of active electrode terminals configured as an electrode array in the form of two concentric circles; and

a high frequency power supply having a plurality of channels, each of the plurality of active electrode terminals coupled to a separate one of the plurality of channels.

64. The system of claim 63, wherein the electrode array comprises from 21 to 23 active electrode terminals.

65. The system of claim 63, wherein the two concentric circles of the electrode array comprise an outer circle of the plurality of active electrode terminals and an inner circle of the plurality of active electrode terminals, wherein the outer circle consists essentially of 14 active electrode terminals.

66. The system of claim 65, wherein the inner circle consists essentially of 7 or 8 active electrode terminals.

67. The system of claim 63, wherein the electrode assembly further comprises a digestion electrode.

68. The system of claim 63, wherein the digestion electrode is adapted for digesting fragments of meniscus cartilage tissue.

69. An electrode assembly for an electrosurgical probe, the electrode assembly comprising:

an electrode array comprising a plurality of active electrode terminals; and

an electrically insulating electrode support having a tissue treatment surface, the plurality of active electrode terminals disposed on the tissue treatment surface, wherein the electrode array comprises a first circular arrangement of the plurality of active electrode terminals and a second circular arrangement of the plurality of active electrode terminals.

70. The electrode assembly of claim 69, wherein the electrode array comprises at least 10 active electrode terminals.

71. The electrode assembly of claim 69, wherein the electrode array comprises from about 20 to 25 active electrode terminals.

72. The electrode assembly of claim 69, wherein the electrode array comprises from 21 to 23 active electrode terminals.

73. The electrode assembly of claim 69, wherein the first circular arrangement comprises an outer ring comprising from about 10 to 20 of the plurality of active electrode terminals.

74. The electrode assembly of claim 73, wherein the outer ring comprises about 14 of the plurality of active electrode terminals.

75. The electrode assembly of claim 73, wherein the second circular arrangement comprises an inner ring comprising from about 5 to 10 of the plurality of active electrode terminals.

76. The electrode assembly of claim 75, wherein the inner ring comprises from 7 to 8 of the plurality of active electrode terminals.

77. The electrode assembly of claim 75, wherein the ratio of the number of active electrode terminals in the outer ring to the number of active electrode terminals in the inner ring is in the range of from about 1.5:

1 to about 2.5;

1.

78. The electrode assembly of claim 69, wherein the first circular arrangement of the plurality of active electrode terminals is concentric with the second circular arrangement of the plurality of active electrode terminals.

79. The electrode assembly of claim 69, wherein each of the plurality of active electrode terminals is substantially orthogonal to the tissue treatment surface.

80. The electrode assembly of claim 69, wherein each of the plurality of active electrode terminals comprises a metal wire.

81. The electrode assembly of claim 80, wherein the wire comprises a material selected from the group consisting of tungsten, stainless steel, platinum, titanium, molybdenum, palladium, iridium, nickel, aluminum, gold, copper, and their alloys.

82. The electrode assembly of claim 69, wherein each of the plurality of active electrode terminals comprises a tungsten wire.

83. The electrode assembly of claim 69, wherein each of the plurality of active electrode terminals has a diameter in the range of from about 0.006 inches to 0.012 inches.

84. The electrode assembly of claim 83, wherein the active electrode terminals are spaced apart by an inter-electrode distance in the range of from about 0.002 inches to 0.008 inches.

85. The electrode assembly of claim 69, wherein the electrode support includes a plurality of electrode ports therein, each of the plurality of electrode ports adapted for accommodating one of the plurality of active electrode terminals.

86. The electrode assembly of claim 69, wherein the tissue treatment surface is substantially planar.

87. The electrode assembly of claim 86, wherein the electrode support has a central bore defining a circular void in the tissue treatment surface.

88. The electrode assembly of claim 87, wherein the circular void is concentric with both the first circular arrangement of the plurality of active electrode terminals and the second circular arrangement of the plurality of active electrode terminals.

89. The electrode assembly of claim 69, wherein the electrode support comprises a silicone rubber extrusion product.

90. The electrode assembly of claim 69, further comprising a digestion electrode adapted for ablating fragments of resected tissue.

91. The electrode assembly of claim 90, wherein the digestion electrode is arranged substantially parallel to the tissue treatment surface.

92. The electrode assembly of claim 90, wherein the digestion electrode is arranged substantially orthogonal to the plurality of active electrode terminals.

93. The electrode assembly of claim 90, wherein the digestion electrode comprises a tungsten wire.

94. The electrode assembly of claim 90, wherein the digestion electrode has a diameter in the range of from about 0.006 inches to 0.012 inches.

95. An electrosurgical apparatus for ablating meniscus tissue from a knee joint, the apparatus comprising:

a shaft having a shaft distal end and a shaft proximal end;

an electrically insulating electrode support disposed on the shaft distal end, the electrode support including a tissue treatment surface;

a plurality of active electrode terminals protruding from the tissue treatment surface, the plurality of active electrode terminals arranged in a circular configuration on the tissue treatment surface; and

an aspiration unit adapted for coupling to a vacuum source, the aspiration unit including an aspiration lumen internal to the shaft, and a suction flow control unit adapted for controlling flow of an aspiration stream within the aspiration lumen.

96. The apparatus of claim 95, wherein the aspiration unit terminates distally in an aspiration port, and the aspiration port comprises a void within the tissue treatment surface.

97. A method of ablating target tissue of a patient'"'"'s joint, comprising:

a) providing an electrosurgical probe, the probe including an electrode array comprising a plurality of active electrode terminals, the electrode array configured as a first circular arrangement of the plurality of active electrode terminals and a second circular arrangement of the plurality of active electrode terminals;

b) positioning the electrode array in at least close proximity to the target tissue; and

c) applying a high frequency voltage between a return electrode and the plurality of active electrode terminals, wherein the voltage is effective in ablating cartilage tissue.

98. The method of claim 97, wherein the voltage applied in said step c) is in the range of from about 200 volts RMS to 1500 volts RMS.

99. The method of claim 97, wherein the probe is coupled to a high frequency power supply for applying the high frequency voltage of said step c), and wherein each of the plurality of active electrode terminals and the return electrode are coupled to a separate channel of the high frequency power supply.

100. The method of claim 97, wherein the probe further includes a digestion electrode adapted for digesting resected tissue fragments, and wherein each of the plurality of active electrode terminals, the return electrode, and the digestion electrode are coupled to a separate channel of the high frequency power supply.

101. The method of claim 97, wherein the patient'"'"'s joint comprises a knee.

102. The method of claim 101, wherein the target tissue comprises a meniscus of the knee.

103. The method of claim 102, further comprising during said step c), manipulating the probe such that the electrode array is translated with respect to the meniscus.

104. The method of claim 97, wherein said step b) involves accessing a medial meniscus or accessing a lateral meniscus of a knee joint.

105. The method of claim 97, wherein said step b) involves introducing a working end of the probe into a knee joint via an incision such that the electrode array is positioned in at least close proximity to the medial meniscus or the lateral meniscus.

106. The method of claim 105, wherein the incision is not more than 1 cm. in length.

107. The method of claim 97, wherein the probe further includes an aspiration unit adapted for aspirating unwanted or excess materials from the patient'"'"'s joint, and the method further comprises aspirating unwanted or excess materials in an aspiration stream via the aspiration unit.

108. The method of claim 107, wherein the unwanted or excess materials comprise gaseous ablation by-products.

109. The method of claim 97, wherein the probe further includes an electrically insulating electrode support having a tissue treatment surface, the plurality of active electrode terminals disposed on the tissue treatment surface, and wherein the electrode array comprises at least 10 of the plurality of active electrode terminals.

110. The method of claim 109, wherein the electrode array comprises from about 20 to 25 of the plurality of active electrode terminals.

111. The method of claim 97, wherein the first circular arrangement of the plurality of active electrode terminals comprises an outer ring comprising from about 10 to 20 of the plurality of active electrode terminals, and the second circular arrangement of the plurality of active electrode terminals comprises an inner ring comprising from about 5 to 10 of the plurality of active electrode terminals.

112. The method of claim 111, wherein the outer ring comprises about 14 of the plurality of active electrode terminals, and the inner ring comprises from 7 to 8 of the plurality of active electrode terminals.

113. The method of claim 97, wherein the first circular arrangement of the plurality of active electrode terminals is concentric with the second circular arrangement of the plurality of active electrode terminals.

114. The method of claim 97, wherein each of the plurality of active electrode terminals comprises a tungsten wire.

115. The method of claim 97, wherein each of the plurality of active electrode terminals has a diameter in the range of from about 0.006 to 0.012 inches.

116. The method of claim 115, wherein the active electrode terminals are spaced apart by an inter-electrode distance in the range of from about 0.002 to 0.008 inches.

117. The method of claim 101, wherein the probe has a curved working end adapted for accessing all regions of both the medial meniscus and the lateral meniscus when the working end is introduced into the knee via a portal of 1 cm or less.

118. The method of claim 117, wherein the working end is curved at an angle in the range of from about 25°

to 35°

with respect to the longitudinal axis of the shaft.

119. A method of removing tissue at a target site of a patient, comprising:

a) advancing a shaft distal end of an electrosurgical probe towards the target site, the shaft distal end having an electrode assembly disposed thereon, the electrode assembly including an electrode array comprising a plurality of active electrode terminals, the electrode array adapted for removing meniscus tissue, and the electrode array configured as two concentric circles of the plurality of active electrode terminals; and

b) applying a high frequency voltage between a return electrode and each of the plurality of active electrode terminals, wherein the meniscus tissue at the target site is ablated.

120. The method of claim 119, further comprising:

c) during said step b), manipulating the probe such that the electrode array is translated with respect to the meniscus tissue.

121. The method of claim 119, further comprising during said step b), resecting a portion of a medial meniscus or of a lateral meniscus to provide fragments of resected meniscus tissue.

122. The method of claim 121, wherein the electrode assembly further includes a digestion electrode adapted for digesting the fragments of resected meniscus tissue, wherein the high frequency voltage is applied between the digestion electrode and the return electrode, whereby the fragments of resected meniscus tissue are digested.

123. The method of claim 122, wherein digesting the fragments of resected meniscus tissue vaporizes at least a portion of the fragments of resected meniscus tissue to form ablation by-products, and the method further comprises aspirating the ablation by-products via an aspiration unit, wherein the aspiration unit is integral with the probe.

124. The method of claim 123, wherein the aspiration unit includes a suction flow control unit for adjusting a flow rate of an aspiration stream within the aspiration unit, and the method further comprises during said step b), adjusting the flow rate of the aspiration stream using the suction flow control unit.