System and method for electrosurgical cutting and ablation

• US 5,697,536 A
• Filed: 11/18/1996
• Issued: 12/16/1997
• Est. Priority Date: 01/07/1992
• Status: Expired due to Term

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Eggers, Philip E., Thapliyal, Hira V.
• Primary Examiner(s): MENDEZ, MANUEL A
• Application Number:
  US08/746,800
• Time in Patent Office: 393 Days
• Field of Search: 604/22, 604/43, 604/48, 604/113, 604/114, 604/264, 604/271, 604/280, 606/31, 606/28, 606/29, 606/39, 606/41, 606/45
• US Class Current: 604/114
• CPC Class Codes: A61B 18/12 by passing a current through the tissue to be heated, e.g. high-frequency current
• 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 2017/00097 one of the thermometric elements being an electrode or the heating element
• 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 2017/00292 mounted on or guided by flexible, e.g. catheter-like, means
• CPC Class Codes: A61B 2017/003 Steerable
• CPC Class Codes: A61B 2017/22001 Angioplasty, e.g. PCTA
• CPC Class Codes: A61B 2017/22038 with a guide wire
• 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 2018/00196 : reciprocating lengthwise
• CPC Class Codes: A61B 2018/00327 : Ear, nose or throat
• CPC Class Codes: A61B 2018/00392 : Transmyocardial revascularisation
• CPC Class Codes: A61B 2018/0047 : Upper parts of the skin, e.g. skin peeling or treatment of wrinkles
• CPC Class Codes: A61B 2018/00476 : Hair follicles
• 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 2018/00642 : with feedback, i.e. closed loop control
• CPC Class Codes: A61B 2018/0066 : without feedback, i.e. open loop control
• CPC Class Codes: A61B 2018/00678 : upper
• CPC Class Codes: A61B 2018/00702 : Power or energy
• CPC Class Codes: A61B 2018/00726 : Duty cycle
• CPC Class Codes: A61B 2018/00761 : Duration
• CPC Class Codes: A61B 2018/00791 : Temperature
• CPC Class Codes: A61B 2018/00797 : measured by multiple temperature sensors
• CPC Class Codes: A61B 2018/00821 : measured by a thermocouple
• CPC Class Codes: A61B 2018/00827 : Current
• CPC Class Codes: A61B 2018/00875 : Resistance or impedance
• CPC Class Codes: A61B 2018/00886 : Duration
• 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 2090/378 : using ultrasound
• CPC Class Codes: A61B 2218/002 : Irrigation
• CPC Class Codes: A61B 2218/007 : Aspiration
• CPC Class Codes: A61F 2/2493 : Transmyocardial revascularisation [TMR] devices
• CPC Class Codes: A61M 25/0133 : Tip steering devices
• CPC Class Codes: A61M 25/0147 : with movable mechanical means, e.g. pull wires
• CPC Class Codes: A61M 25/0158 : with magnetic or electrical means, e.g. by using piezo materials, electroactive polymers, magnetic materials or by heating of shape memory materials

Abstract

An electrosurgical probe (10) comprises a shaft (13) having an electrode array (12) at its distal end and a connector (19) at its proximal end for coupling the electrode array to a high frequency power supply (28). The shaft includes a return electrode (55, 56) recessed from its distal end and enclosed within an insulating jacket (18). The return electrode defines an inner passage (83) electrically connected to both the return electrode and the electrode array for passage of an electrically conducting liquid (50). By applying high frequency voltage to the electrode array and the return electrode, the electrically conducting liquid generates a current flow path between the target site and the return electrode so that target tissue may be cut or ablated. The probe is particularly useful in dry environments, such as the mouth or abdominal cavity, because the electrically conducting liquid provides the necessary return current path between the return electrode and the target site.

Claims

1. An electrosurgical system for use with a high frequency power supply and an electrically conducting fluid supply, the system comprising:

an electrosurgical probe comprising a shaft having a proximal end and a distal end, an electrode terminal disposed near the distal end, and a connector near the proximal end of the shaft for electrically coupling the electrode terminal to the electrosurgical power supply;

a return electrode adapted to be electrically coupled to the electrosurgical power supply; and

a fluid delivery element defining a fluid path in electrical contact with the return electrode and the electrode terminal, the fluid path having an inlet adapted to be fluidly coupled to the electrically conducting fluid supply for directing fluid along the fluid path to generate a current flow path between the return electrode and the electrode terminal.

2. An electrosurgical system as in claim 1, wherein the return forms a portion of the shaft of the electrosurgical probe.

3. An electrosurgical system as in claim 2 further including an insulating member circumscribing the return electrode, the return electrode being sufficiently spaced from the electrode terminal to minimize direct contact between the return electrode and a body structure at the target site when the electrode terminal is positioned in close proximity or in partial contact with the body structure.

4. An electrosurgical system as in claim 2, wherein the return electrode is an inner tubular member and the fluid delivery element comprises an axial lumen within the return electrode, the axial lumen forming at least a portion of the fluid path and having an inlet in communication with the electrically conducting fluid supply and an outlet in fluid communication with the electrode terminal.

5. An electrosurgical system as in claim 2, wherein the return electrode is an outer tubular member, the shaft further comprising an insulating member, wherein the fluid delivery element comprises an axial passage between the insulating member and the return electrode, the axial passage forming at least a portion of the fluid path and having an inlet in communication with the electrically conducting fluid supply and an outlet in fluid and electrical communication with the electrode terminal.

6. An electrosurgical system as in claim 1 wherein the fluid delivery element comprises a fluid supply instrument separate from the electrosurgical probe, the return electrode forming a portion of the fluid supply instrument.

7. An electrosurgical system as in claim 6 wherein the return electrode is a tubular member defining an axial lumen therein, the axial lumen being electrically connected to the tubular member and having an inlet in communication with the fluid supply and an outlet for discharging the electrically conducting fluid towards the active electrode.

8. An electrosurgical system as in claim 7 wherein the fluid supply instrument comprises an electrically insulating sheath around the tubular member, the tubular member being proximally recessed from a distal end of the sheath.

9. An electrosurgical system as in claim 1 wherein the electrode terminal comprises an electrode array disposed near the distal end of the shaft, the array including a plurality of electrically isolated electrode terminals disposed over a contact surface.

10. The electrosurgical system of claim 9 further comprising a plurality of current limiting elements each coupled to one of the electrode terminals for independently controlling current flow to each of the electrode terminals to inhibit power dissipation into the medium surrounding the target site.

11. The electrosurgical system of claim 9 further comprising means for independently controlling power to the electrode terminals based on the electrical impedance between each of the electrode terminals and the return electrode.

12. The electrosurgical system of claim 9 wherein the distal surface of the array of electrode terminals is circular in shape with a diameter in the range from 1 mm to 10 mm.

13. The electrosurgical system of claim 9 wherein the shape of the distal surface of the array of electrode terminals has an effective length of 1 mm to 20 mm and an effective width of 0.5 mm to 7.0 mm.

14. The electrosurgical system of claim 1 wherein the electrode terminal comprises a single active electrode disposed near the distal end of the shaft.

15. The electrosurgical system of claim 1 wherein the target site is selected from the group consisting essentially of the abdominal cavity, thoracic cavity, knee, shoulder, hip, hand, foot, elbow, mouth, spine, ear, nose, throat, epidermis and dermis of the patient'"'"'s body.

16. The electrosurgical system of claim 1 further comprising a current limiting element for controlling current flow through the electrode terminal to inhibit power dissipation into the medium surrounding the target site.

17. The electrosurgical system of claim 16 wherein the electrically conducting fluid between the electrode terminal and the return electrode has an inherent capacitance, wherein the inherent capacitance of the tissue and electrically conducting fluid between the electrode terminal and the return electrode combined with the current limiting element together form a series resonant output circuit.

18. The system of claim 17 wherein the series resonant circuit has a resonant frequency that varies with changes in the inherent capacitance between the electrode terminal and the return electrode.

19. The electrosurgical system of claim 16 wherein the current limiting element is an active current limiting element for actively limiting current to the electrode terminal based on the electrical impedance between the electrode terminal and the return electrode.

20. The electrosurgical system of claim 19 wherein the active current limiting element measures current flow for a given applied voltage.

21. The electrosurgical system of claim 19 wherein the active current limiting element comprises an impedance sensor for indicating an electrical impedance less than a threshold level.

22. The electrosurgical system of claim 16 wherein the current limiting element is a passive current limiting element selected from the group consisting essentially of inductors, capacitors, resistors and combinations thereof.

23. The electrosurgical system of claim 1 wherein the height of the most distal portion of the electrode terminal relative to the most proximal portion of the electrode terminal exposed to the electrically conducting fluid is in the range from 0 to 2 mm.

24. The electrosurgical system of claim 1 wherein the distance between the most distal portion of the return electrode and the most proximal portion of the electrode terminal is in the range from 0.5 to 10 mm.

25. The electrosurgical system of claim 1 wherein the distal surface of the electrode terminal has a shape selected from the group consisting essentially of flat, concave, convex, hemispherical, linear (in-line), pyramidal, conical and cylindrical.

26. The electrosurgical system of claim 1 wherein the fluid delivery element further comprises a control valve positioned on the shaft of the probe for controlling flow of the electrically conducting fluid through the fluid path.

27. The electrosurgical system of claim 1 further comprising means for controlling power to the electrode terminal based on the electrical impedance between the electrode terminal and the return electrode.

28. The electrosurgical system of claim 1 further comprising an insulating matrix surrounding and supporting the electrode terminal to electrically isolate a proximal portion of the electrode terminal from the electrically conducting fluid, the insulating matrix comprising an inorganic material.

29. The electrosurgical system of claim 28 wherein the inorganic material is selected from the group consisting essentially of ceramic, glass and glass/ceramic compositions.

30. The electrosurgical system of claim 1 wherein the electrode terminal and the return electrode are configured to effect the electrical breakdown of tissue in the immediate vicinity of the electrode terminal when high frequency voltage is applied between the electrode terminal and the return electrode in the presence of electrically conducting fluid.

31. The electrosurgical system of claim 1 wherein the electrically conducting fluid is selected from the group consisting essentially of blood and electrolytic irrigants.

32. The electrosurgical system of claim 1 wherein the electrically conducting liquid comprises saline.

33. The electrosurgical system of claim 1 wherein the electrode terminal has a distal portion configured for generating high electric field intensities sufficient to cause molecular disintegration of a body structure at the target site.

34. The electrosurgical system of claim 1 further comprising a temperature sensor adjacent the electrode terminal, the temperature sensor being adapted to be electrically coupled to the high frequency voltage source such that power delivery to the electrical terminal is limited if the measured temperature exceeds a threshold value.

35. The electrosurgical system of claim 34 wherein the temperature sensor is integral with the electrode terminal.

37. The electrosurgical system of claim 1 wherein the shape of the distal surface of the electrode terminal has an effective length of 1 mm to 20 mm and an effective width of 0.5 mm to 7.0 mm.

38. The system of claim 1 wherein the electrode terminal is configured for the cutting of tissue.

39. The system of claim 1 wherein the probe comprises a concave-shaped portion, the electrode terminal being disposed within the concave-shaped portion such that the concave-shaped portion at least partially surrounds the target site when the electrode terminal is brought into at least partial contact or close proximity with the target site.

40. The system of claim 1 wherein the probe comprises a lateral surface, the electrode terminal being positioned on the lateral surface such that the electrode terminal may be brought into at least partial contact or close proximity with the tissue surfaces which are substantially tangent to the electrosurgical probe.

41. The system of claim 1 wherein the electrode terminal and the return electrode are configured, upon the application of sufficient voltage therebetween, to effect the ablution of tissue adjacent the electrode terminal such that a portion of said tissue is volumetrically removed.

42. The system of claim 1 wherein the electrode terminal is disposed at the distal tip of the electrosurgical probe.

43. The system of claim 42 wherein the return electrode is disposed proximally of the electrode terminal on the electrosurgical probe.

44. The system of claim 1 wherein the electrode terminal is a flexible electrode terminal disposed at the distal tip of the probe, the flexible electrode terminal being extendable relative to the distal tip of the probe.

36. The electrosurgical system of 1 wherein the distal surface of the electrode terminal is circular in shape with a diameter in the range from 1 mm to 10 mm.

45. An electrosurgical system for applying electrical energy to a target site on a structure within or on a patient'"'"'s body, the system comprising:

a high frequency power supply;

an electrosurgical probe comprising a shaft having a proximal end and a distal end, an electrode terminal disposed near the distal end, and a connector near the proximal end of the shaft electrically coupling the electrode terminal to the electrosurgical power supply;

a return electrode electrically coupled to the electrosurgical power supply; and

an electrically conducting fluid supply for directing electrically conducting fluid to the target site such that the electrically conducting fluid generates a current flow path between the return electrode and the electrode terminal.

46. An electrosurgical system as in claim 45, wherein the return electrode forms a portion of the shaft of the electrosurgical probe.

47. An electrosurgical system as in claim 46 further including an insulating member circumscribing the return electrode, the return electrode being sufficiently spaced from the electrode terminal to minimize direct contact between the return electrode and the patient'"'"'s tissue.

48. An electrosurgical system as in claim 46, wherein the return electrode is an inner tubular member defining an axial lumen within the return electrode, the axial lumen having an inlet in communication with the electrically conducting fluid supply and an outlet in fluid communication with the electrode terminal.

49. An electrosurgical system as in claim 46, wherein the return electrode is an outer tubular member, the shaft further comprising an insulating member defining an axial passage between the insulating member and the return electrode, the axial passage having an inlet in communication with the electrically conducting fluid supply and an outlet in fluid and electrical communication with the electrode terminal.

50. An electrosurgical system as in claim 45 further including a fluid supply instrument separate from the electrosurgical probe, the return electrode forming a portion of the fluid supply instrument.

51. An electrosurgical system as in claim 50 wherein the return electrode is a tubular member defining an axial lumen therein, the axial lumen being electrically connected to the tubular member and having an inlet in communication with the fluid supply and an outlet for discharging the electrically conducting fluid towards the active electrode.

52. The electrosurgical system of claim 51 further comprising a plurality of current limiting elements each coupled to one of the electrode terminals for independent controlling current flow through the electrode terminals to inhibit power dissipation into the medium surrounding the target site.

53. An electrosurgical system as in claim 45 wherein the electrode terminal comprises an electrode array disposed near the distal end of the shaft, the array including a plurality of electrically isolated electrode terminals disposed over a contact surface.

54. The electrosurgical system of claim 53 further comprising means for independently controlling power to the electrode terminals based on the electrical impedance between each of the electrode terminals and the return electrode.

55. The electrosurgical system of claim 45 wherein the electrode terminal comprises a single active electrode disposed near the distal end of the shaft.

56. The electrosurgical system of claim 45 wherein the target site is selected from the group consisting essentially of the abdominal cavity, thoracic cavity, knee, shoulder, hip, hand, foot, elbow, mouth, spine, ear, nose, throat, epidermis and dermis of the patient'"'"'s body.

57. The electrosurgical system of claim 45 further comprising a current limiting element for controlling current flow through the electrode terminal to inhibit power dissipation into the medium surrounding the target site.

58. The electrosurgical system of claim 45 wherein the frequency of the voltage applied between the return electrode and the electrode terminal is in the range of about 20 kHz and 20 Mhz.

59. The electrosurgical system of claim 45 wherein the voltage applied between the electrode terminal and the return electrode is in the range from 10 volts (RMS) to 1000 volts (RMS).

60. The electrosurgical system of claim 45 further comprising means for controlling power to the electrode terminal based on the electrical impedance between the electrode terminal and the return electrode.

61. The electrosurgical system of claim 45 further comprising an insulating matrix surrounding and supporting electrode terminal to electrically isolate a proximal portion of the electrode terminal from the electrically conducting fluid, the insulating matrix comprising an inorganic material.

62. The electrosurgical system of claim 45 wherein the inorganic material is selected from the group consisting essentially of ceramic, glass and glass/ceramic compositions.

63. An electrosurgical system for applying electrical energy to a target site on a structure within or on a patient'"'"'s body, the system comprising:

a high frequency power supply;

an electrosurgical probe comprising a shaft having a proximal end and a distal end, an electrode terminal disposed near the distal end, and a connector near the proximal end of the shaft electrically coupling the electrode terminal to the electrosurgical power supply;

a return electrode electrically coupled to the electrosurgical power supply;

an electrically conducting fluid supply;

a fluid delivery element defining a fluid path electrically coupled to the electrode terminal for directing electrically conducting fluid to the target site and the electrode terminal to substantially surround the electrode terminal with electrically conducting fluid and to locate electrically conducting fluid between the electrode terminal and the target site.

64. The system of claim 63 wherein the return electrode is located on a surface of the patient'"'"'s body.