Electrosurgical apparatus and methods for treating tissue

• US 20010051802A1
• Filed: 01/19/2001
• Published: 12/13/2001
• Est. Priority Date: 05/10/1993
• Status: Active Grant

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Masterson, Steven P., Woloszko, Jean, Ormsby, Theodore C., Davison, Terry S., Willink, Christopher L.
• Granted Patent: US 6,589,237 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• 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 18/1482 having a long rigid shaft for accessing the inner body transcutaneously in minimal invasive surgery, e.g. laparoscopy
• CPC Class Codes: A61B 18/1485 having a short rigid shaft for accessing the inner body through natural openings
• CPC Class Codes: A61B 18/149 bow shaped or with rotatable body at cantilever end, e.g. for resectoscopes, or coagulating rollers
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/00101 using an array of thermosensors
• CPC Class Codes: A61B 2017/00247 Making holes in the wall of the heart, e.g. laser Myocardial revascularization
• CPC Class Codes: A61B 2018/00029 open
• CPC Class Codes: A61B 2018/00083 low, i.e. electrically insulating
• CPC Class Codes: A61B 2018/00119 with metal oxide nitride
• CPC Class Codes: A61B 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/00178 Electrical connectors
• CPC Class Codes: A61B 2018/00291 using suction
• CPC Class Codes: A61B 2018/00327 Ear, nose or throat
• CPC Class Codes: A61B 2018/00392 Transmyocardial revascularisation
• CPC Class Codes: A61B 2018/00505 Urinary tract
• CPC Class Codes: A61B 2018/00577 : Ablation
• CPC Class Codes: A61B 2018/00583 : Coblation, i.e. ablation using a cold plasma
• CPC Class Codes: A61B 2018/00601 : Cutting
• CPC Class Codes: A61B 2018/00666 : using a threshold value
• CPC Class Codes: A61B 2018/00678 : upper
• CPC Class Codes: A61B 2018/00702 : Power or energy
• CPC Class Codes: A61B 2018/0072 : Current
• CPC Class Codes: A61B 2018/00726 : Duty cycle
• CPC Class Codes: A61B 2018/00779 : Power or energy
• CPC Class Codes: A61B 2018/00791 : Temperature
• CPC Class Codes: A61B 2018/00827 : Current
• CPC Class Codes: A61B 2018/00875 : Resistance or impedance
• CPC Class Codes: A61B 2018/00982 : combined with or comprising means for visual or photographic inspections inside the body, e.g. endoscopes
• CPC Class Codes: A61B 2018/1213 : creating an arc
• CPC Class Codes: A61B 2018/124 : switching the output to different electrodes, e.g. sequentially
• CPC Class Codes: A61B 2018/1253 : monopolar
• CPC Class Codes: A61B 2018/126 : bipolar
• CPC Class Codes: A61B 2018/1273 : including multiple generators in one device
• CPC Class Codes: A61B 2018/1407 : Loop
• CPC Class Codes: A61B 2018/1467 : using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/1472 : for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2018/162 : located on the probe body
• CPC Class Codes: A61B 2018/165 : Multiple indifferent electrodes
• CPC Class Codes: A61B 2218/002 : Irrigation
• CPC Class Codes: A61B 2218/007 : Aspiration

Abstract

Electrosurgical methods and apparatus for removing tissue from a target site of a patient. An electrosurgical suction apparatus includes an aspiration channel in communication with a distal aspiration port, and an electrode support having a plurality of active electrodes disposed thereon, the plurality of active electrodes spanning the aspiration port. Each of the plurality of active electrodes is adapted for removing tissue from a target site to form low molecular weight ablation by-products. Each of the plurality of active electrodes is also adapted for digesting resected tissue fragments to yield low molecular weight ablation by-products. Ablation by-products and resected tissue fragments are readily removed from the target site via an aspiration stream flowing proximally through the aspiration channel. In one embodiment, each of a plurality of active electrodes protrude in different directions from a beveled treatment surface of the electrode support, and each of the plurality of active electrodes extend from the beveled treatment surface by substantially the same orthogonal distance.

Claims

1. An electrosurgical suction apparatus for removing tissue from a target site, comprising:

an aspiration unit adapted for coupling to a vacuum source, the aspiration unit including an aspiration channel terminating in a distal aspiration port; and

a plurality of active electrodes, each of the plurality of active electrodes comprising a length of wire extending transversely across the aspiration port, wherein at least a first of the plurality of active electrodes extends distally in a first direction and at least a second of the plurality of active electrodes extends distally in a second direction, wherein the first and second directions are different.

2. The apparatus of

claim 1

, wherein each of the plurality of active electrodes includes a loop portion, the loop portions arranged substantially parallel to each other.

3. The apparatus of

claim 1

, wherein each of the plurality of active electrodes includes a distal face, and each distal face is oriented in a different direction.

4. The apparatus of

claim 1

, further comprising a shaft having a shaft distal end portion and a shaft proximal end portion, and an electrode support disposed on the shaft distal end portion, each of the plurality of active electrodes disposed on the electrode support.

5. The apparatus of

claim 4

, wherein the electrode support includes a beveled treatment surface.

6. The apparatus of

claim 4

, wherein the electrode support comprises a material selected from the group consisting of a fluoropolymer, a glass, a ceramic, and a silicone rubber.

7. The apparatus of

claim 4

, further comprising an insulating sleeve covering a portion of the shaft, the shaft comprising an electrically conducting material, the insulating sleeve terminating in a sleeve distal end at a location proximal to the electrode support to define an exposed portion of the shaft located between the sleeve distal end and the electrode support, and the exposed portion comprising a return electrode.

8. The apparatus of

claim 1

, further comprising a shaft having a shaft distal end portion and a shaft proximal end portion, and an electrode support disposed on the shaft distal end portion, the electrode support having a treatment surface, each of the plurality of active electrodes protruding from the treatment surface, the treatment surface encircling the aspiration port, each of the plurality of active electrodes including a distal face, wherein the orthogonal distance from the treatment surface to the distal face is substantially the same for each of the plurality of active electrodes.

9. The apparatus of

claim 1

, wherein each of the plurality of active electrodes comprises a loop portion, a first free end terminating within an electrically insulating material, and a second connected end coupled to an active electrode lead.

10. The apparatus of

claim 1

, further comprising:

a shaft having a shaft distal end portion;

a return electrode arranged on the shaft distal end portion at a location proximal to the plurality of active electrodes; and

an outer sheath external to the shaft, the outer sheath defining an annular fluid delivery channel external to the shaft, and the outer sheath terminating in an annular fluid delivery port at a location proximal to the return electrode.

11. The apparatus of

claim 1

, wherein each of the plurality of active electrodes comprises a metal wire comprising a material selected from the group consisting of:

platinum, tungsten, palladium, iridium, and titanium.

12. The apparatus of

claim 1

, wherein each of the plurality of active electrodes comprises a metal wire comprising from about 85% to 95% platinum and from about 5% to 15% iridium.

13. The apparatus of

claim 1

, further comprising a baffle located proximal to the plurality of active electrodes.

14. An electrosurgical suction apparatus for removing tissue from a target site, comprising:

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

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

a plurality of active electrodes, each of the plurality of active electrodes including a loop portion, the loop portions protruding from the treatment surface, the loop portions arranged substantially parallel to each other, and the loop portions having a plurality of different orientations with respect to the treatment surface; and

an aspiration unit adapted for coupling to a vacuum source, the aspiration unit including an aspiration channel terminating in at least one aspiration port.

15. The apparatus of

claim 14

, wherein the plurality of active electrodes comprise a first, a second, and a third active electrode, the second active electrode flanked by the first and third active electrodes, each of the plurality of active electrodes further including a first free end, and a second connected end, and wherein in the case of the first and third active electrodes the orientation with respect to the treatment surface of the connected end and the free end is different from the orientation of the loop portion.

16. The apparatus of

claim 14

, wherein each of the plurality of active electrodes includes a distal face, each of the distal faces oriented in a different direction with respect to the treatment surface.

17. The apparatus of

claim 16

, wherein the plurality of active electrodes comprise a first, a second, and a third active electrode, the second active electrode flanked by the first and third active electrodes.

18. The apparatus of

claim 17

, wherein the second active electrode extends in the direction of the longitudinal axis of the shaft.

19. The apparatus of

claim 18

, wherein the distal face of the second active electrode extends in the direction of the longitudinal axis of the shaft.

20. The apparatus of

claim 18

, wherein the distal face of each of the first and third active electrodes is oriented substantially towards the second active electrode.

21. The apparatus of

claim 16

, wherein the first, second, and third active electrodes extend from the treatment surface by substantially the same orthogonal distance.

22. The apparatus of

claim 14

, wherein each of the plurality of active electrodes further includes a connected end, and the connected end of at least one of the plurality of active electrodes has a first orientation with respect to the treatment surface and the loop portion of the at least one of the plurality of active electrodes has a second orientation with respect to the treatment surface.

23. The apparatus of

claim 14

, wherein the treatment surface includes a rounded perimeter.

24. The apparatus of

claim 14

, wherein the treatment surface is beveled at an angle in the range of from about 25°

to 35°

.

25. The apparatus of

claim 14

, wherein the electrode support comprises an alumina ceramic.

26. The apparatus of

claim 14

, further comprising a baffle arranged transversely within the shaft distal end portion, the baffle defining a plurality of aspiration ports at the distal terminus of the aspiration channel, and the baffle located proximal to the plurality of active electrodes.

27. The apparatus of

claim 26

, wherein the baffle is recessed within the electrode support to define a holding chamber adapted for retaining tissue fragments which do not readily pass through the plurality of aspiration ports.

28. The apparatus of

claim 14

, wherein each of the plurality of active electrodes comprises a length of wire extending transversely across the aspiration port.

29. The apparatus of

claim 14

, wherein each of the plurality of active electrodes has a substantially rectangular cross-sectional shape.

30. The apparatus of

claim 14

, wherein each of the plurality of active electrodes consists essentially of a platinum/iridium alloy.

31. An electrosurgical suction apparatus for removing tissue from a target site, comprising:

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

an electrically insulating electrode support disposed on the shaft distal end portion, the electrode support including a beveled treatment surface encircling an aspiration port; and

a plurality of active electrodes disposed on the electrode support, each of the plurality of active electrodes comprising a loop portion bridging the aspiration port, and a first free end terminating within an electrically insulating material.

32. The apparatus of

claim 31

, wherein the loop portions are arranged substantially parallel to each other.

33. The apparatus of

claim 31

, wherein each loop portion has a substantially rectangular cross-sectional shape.

34. The apparatus of

claim 31

, wherein the loop portion of each of the plurality of active electrodes is oriented in a different direction with respect to the treatment surface.

35. The apparatus of

claim 34

, wherein the plurality of active electrodes are three in number.

36. The apparatus of

claim 31

, wherein each of the plurality of active electrodes includes a distal face, and each distal face is oriented in a different direction with respect to the treatment surface.

37. An electrosurgical system for removing tissue from a target site, comprising:

an electrosurgical suction apparatus; and

a high frequency power supply coupled to the suction apparatus for supplying a high frequency voltage to the suction apparatus, the suction apparatus including;

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

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

a plurality of active electrodes, each of the plurality of active electrodes independently coupled to a first pole of the high frequency power supply, each of the plurality of active electrodes comprising a loop portion, each of the loop portions arranged substantially parallel to each other on the treatment surface;

a return electrode on the shaft distal end portion at a location proximal to the electrode support, the return electrode coupled to a second pole of the high frequency power supply; and

an aspiration unit including an aspiration port in communication with an aspiration channel, the aspiration port encircled by the electrode support.

38. The electrosurgical system of

claim 37

, wherein each of the plurality of active electrodes is adapted for ablating tissue via molecular dissociation of tissue components to form low molecular weight ablation by-products and resected tissue fragments, and each of the plurality of active electrodes is further adapted for digesting the resected tissue fragments via molecular dissociation of tissue components to form low molecular weight ablation by-products.

39. The electrosurgical system of

claim 37

, wherein the aspiration unit is adapted for removing ablation by-products and resected tissue fragments from a surgical field.

40. The electrosurgical system of

claim 37

, wherein, in the presence of an electrically conductive fluid, each of the plurality of active electrodes generates a plasma upon application of a high frequency voltage thereto, and each of the plurality of active electrodes are capable of ablating a tissue via a cool ablation process, wherein tissue components undergo molecular dissociation, wherein the tissue which undergoes molecular dissociation is exposed to a temperature not exceeding 90°

C.

41. The electrosurgical system of

claim 37

, wherein the high frequency voltage is characterized by a peak-to-peak voltage in the range of from about 10 to 2000 volts, a RMS voltage in the range of from about 5 volts to 1000 volts, and a frequency in the range of from about 5 kHz to 20 MHz.

42. The system of

claim 37

, wherein each loop portion spans the aspiration port.

43. The system of

claim 37

, wherein each of the plurality of active electrodes further comprises a first free end terminating within an electrically insulating material, and a second connected end coupled to an active electrode lead, the active electrode lead in communication with the high frequency power supply.

44. The system of 43, wherein at least one of the active electrode and the active electrode lead comprises a platinum/iridium alloy.

45. A method of removing tissue from a target site of a patient, comprising:

a) positioning a shaft distal end of an electrosurgical apparatus in the vicinity of the target site, the shaft distal end bearing an electrically insulating electrode support, the electrode support including a treatment surface having a plurality of active electrodes disposed thereon, each of the plurality of active electrodes including a loop portion traversing an aspiration port, the loop portions arranged substantially parallel to each other, wherein at least one of the plurality of active electrodes makes contact with, or is in close proximity to, the tissue at the target site;

b) applying a high frequency voltage between the plurality of active electrodes and a return electrode, wherein at least a portion of the tissue at the target site is ablated via molecular dissociation of tissue components; and

c) aspirating unwanted materials from the target site.

46. The method of

claim 45

, wherein the loop portions are oriented in a plurality of different directions with respect to the treatment surface.

47. The method of

claim 45

, wherein each of the plurality of active electrodes is capable of ablating tissue from the target site via molecular dissociation of tissue components to generate low molecular weight ablation by-products and resected tissue fragments.

48. The method of

claim 45

, wherein each of the plurality of active electrodes is capable of ablating resected tissue fragments via molecular dissociation of tissue components to generate low molecular weight ablation by-products.

49. The method of

claim 45

, further comprising:

prior to said step b), delivering an electrically conductive fluid to the shaft distal end or to the target site, wherein the electrically conductive fluid provides a current flow path between at least one of the plurality of active electrodes and the return electrode.

50. The method of

claim 45

, wherein the tissue at the target site is modified by the volumetric removal of the tissue.

51. The method of

claim 45

, wherein the tissue at the target site is ablated to a controlled depth to form a modified tissue having a smooth, contoured surface.

52. The method of

claim 45

, further comprising:

manipulating the apparatus such that the plurality of active electrodes are moved with respect to a surface of the tissue.

53. The method of

claim 52

, wherein manipulating the apparatus comprises reciprocating the treatment surface with respect to the tissue.

54. The method of

claim 45

, wherein each of the plurality of active electrodes includes a distal face, and the method further comprises:

moving each distal face with respect to the tissue, wherein the tissue is ablated via molecular dissociation of tissue components in a region of movement of each distal face.

55. The method of

claim 45

, wherein the high frequency voltage applied between the plurality of active electrodes and the return electrode is in the range of from about 10 to 500 volts RMS.

56. The method of

claim 45

, wherein the tissue at the target site is exposed to a temperature in the range of from about 40°

C. to 90°

C.

57. The method of

claim 45

, wherein the electrode support comprises a material selected from the group consisting of a ceramic, a glass, a fluoropolymer, and a silicone rubber.

58. The method of

claim 45

, wherein each of the plurality of active electrodes comprises a material selected from the group consisting of platinum, tungsten, palladium, iridium, and titanium.

59. The method of

claim 45

, wherein each of the plurality of active electrodes comprises from about 85% to 95% platinum and from about 5% to 15% iridium.

60. The method of

claim 45

, wherein the electrode support comprises an alumina ceramic.

61. The method of

claim 45

, wherein the electrode support is beveled at an angle in the range of from about 25°

to 35°

.