Apparatus and method for creating, maintaining, and controlling a virtual electrode used for the ablation of tissue

• US 20040215183A1
• Filed: 05/18/2004
• Published: 10/28/2004
• Est. Priority Date: 02/22/1995
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Goetz, Steven M., Christopherson, Mark A., Hoey, Michael F.
• Granted Patent: US 7,247,155 B2
• Time in Patent Office: Days
• US Class Current: 606/34
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1233 with circuits for assuring patient safety
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• CPC Class Codes: A61B 18/18 by applying electromagnetic radiation, e.g. microwaves radiation therapy A61N5/00
• CPC Class Codes: A61B 18/1815 using microwaves
• CPC Class Codes: A61B 2018/00029 open
• CPC Class Codes: A61B 2018/00196 reciprocating lengthwise
• 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 2018/00708 switching the power on or off
• CPC Class Codes: A61B 2018/00779 Power or energy
• 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 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/1213 creating an arc
• CPC Class Codes: A61B 2018/1253 monopolar
• CPC Class Codes: A61B 2018/1417 Ball
• CPC Class Codes: A61B 2018/1472 : for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2018/1475 : Electrodes retractable in or deployable from a housing
• CPC Class Codes: A61B 2218/002 : Irrigation
• CPC Class Codes: A61B 2218/007 : Aspiration

Abstract

The present invention provides an apparatus and a method for producing a virtual electrode within or upon a tissue to be treated with radio frequency alternating electric current, such tissues including but not limited to liver, lung, cardiac, prostate, breast, and vascular tissues and neoplasms. An apparatus in accord with the present invention includes a supply of a conductive or electrolytic fluid to be provided to the patient, an alternating current generator, and a processor for creating, maintaining, and controlling the ablation process by the interstitial or surficial delivery of the fluid to a tissue and the delivery of electric power to the tissue via the virtual electrode. A method in accord with the present invention includes delivering a conductive fluid to a predetermined tissue ablation site for a predetermined time period, applying a predetermined power level of radio frequency current to the tissue, monitoring at least one of several parameters, and adjusting either the applied power and/or the fluid flow in response to the measured parameters.

Claims

1-5_Cancelled_. -5.(Cancelled)

6. A method for treating tissue comprising:

providing radio frequency power at a power level;

providing a fluid at a fluid flow rate;

controlling the fluid flow rate based upon the power level; and

applying the radio frequency power with the fluid to treat the tissue from a surgical instrument.

7. The method of claim 6, wherein:

the fluid flow rate is controlled by use of an equation.

8. The method of claim 7, wherein:

the equation comprises a quadratic equation.

9. The method of claim 7, wherein:

the equation comprises a higher order equation.

10. The method of claim 6, wherein:

the fluid flow rate is controlled by use of a linear relationship.

11. The method of claim 6, wherein:

the fluid flow rate is controlled by use of a step relationship.

12. The method of claim 6, wherein:

the fluid flow rate is controlled by use of a look-up table.

13. The method of claim 6, wherein:

controlling the fluid flow rate based upon the power level is performed by a control apparatus comprising a microprocessor.

14. The method of claim 6, wherein:

the surgical instrument comprises a monopolar surgical instrument.

15. The method of claim 6, wherein:

the surgical instrument comprises a bipolar surgical instrument.

16. A method for treating tissue comprising:

providing radio frequency power at a power level;

providing a fluid at a fluid flow rate;

providing a relationship between the fluid flow rate and the power level; and

applying the radio frequency power with the fluid to treat the tissue from a surgical instrument.

17. The method of claim 16, wherein:

the relationship is provided by an equation.

18. The method of claim 17, wherein:

the equation comprises a quadratic equation.

19. The method of claim 17, wherein:

the equation comprises a higher order equation.

20. The method of claim 16, wherein:

the relationship comprises a linear relationship.

21. The method of claim 16, wherein:

the relationship comprises a step relationship.

22. The method of claim 16, wherein:

the relationship is provided by a look-up table.

23. The method of claim 16 further comprising:

the relationship between the fluid flow rate and the power level resides in a memory of a control apparatus.

24. The method of claim 16, wherein:

the surgical instrument comprises a monopolar surgical instrument.

25. The method of claim 16, wherein:

the surgical instrument comprises a bipolar surgical instrument.

35. The method of claim 16, wherein:

the surgical instrument comprises a bipolar surgical instrument.

26. A method for treating tissue comprising:

providing radio frequency power at a power level;

providing a fluid at a fluid flow rate;

relating the fluid flow rate to the power level; and

applying the radio frequency power with the fluid to treat the tissue from a surgical instrument.

27. The method of claim 26, wherein:

the fluid flow rate is related by use of an equation.

28. The method of claim 27, wherein:

the equation comprises a quadratic equation.

29. The method of claim 27, wherein:

the equation comprises a higher order equation.

30. The method of claim 26, wherein:

the fluid flow rate is related by use of a linear relationship.

31. The method of claim 26, wherein:

the fluid flow rate is related by use of a step relationship.

32. The method of claim 26, wherein:

the fluid flow rate is related by use of a look-up table.

33. The method of claim 26, wherein:

relating the fluid flow rate to the power level is performed by a control apparatus comprising a microprocessor and a memory.

34. The method of claim 26, wherein:

the surgical instrument comprises a monopolar surgical instrument.

36. A method for treating tissue comprising:

providing radio frequency power at a power level;

providing a fluid at a fluid flow rate;

applying the radio frequency power with the fluid to treat the tissue from a surgical instrument; and

adjusting the fluid flow rate based upon the power level.

37. The method of claim 36, wherein:

the fluid flow rate is adjusted by use of an equation.

38. The method of claim 37, wherein:

the equation comprises a quadratic equation.

39. The method of claim 37, wherein:

the equation comprises a higher order equation.

40. The method of claim 36, wherein:

the fluid flow rate is adjusted by use of a linear relationship.

41. The method of claim 36, wherein:

the fluid flow rate is adjusted by use of a step relationship.

42. The method of claim 36, wherein:

the fluid flow rate is adjusted by use of a look-up table.

43. The method of claim 36, wherein:

adjusting the fluid flow rate based upon the power level is performed by a control apparatus comprising a microprocessor.

44. The method of claim 36, wherein:

the surgical instrument comprises a monopolar surgical instrument.

45. The method of claim 36, wherein:

the surgical instrument comprises a bipolar surgical instrument.

46. A system for treating tissue comprising:

a radio frequency power source to provide radio frequency power;

a fluid source to provide a fluid;

an electrosurgical instrument connectable to the radio frequency power source and the fluid source, the electrosurgical instrument to provide the radio frequency power from the power source and the fluid from the fluid source to treat the tissue; and

a control apparatus to control a fluid flow rate of the fluid based upon a power level of the radio frequency power.

47. The system of claim 46, wherein:

the control apparatus comprises a microprocessor.

48. The system of claim 47 further comprising:

a pump.

49. The system of claim 48, wherein:

the pump, the microprocessor and the power source are contained in a single housing.

50. The system of claim 49, wherein:

the housing further contains the fluid source.

51. A system for treating tissue comprising:

a radio frequency power source to provide radio frequency power;

a fluid source to provide a fluid;

an electrosurgical instrument connectable to the radio frequency power source and the fluid source, the electrosurgical instrument to provide the fluid from the fluid source and the radio frequency power from the power source to treat the tissue; and

a control apparatus to provide a relationship between a fluid flow rate of the fluid and a power level of the radio frequency power.

52. The system of claim 51, wherein:

the relationship resides in a memory of the control apparatus.

53. The system of claim 52 further comprising:

a pump.

54. The system of claim 53, wherein:

the pump, the memory and the power source are contained in a single housing.

55. The system of claim 54, wherein:

the housing further contains the fluid source.

56. A system for treating tissue comprising:

a radio frequency power source to provide radio frequency power;

a fluid source to provide a fluid;

an electrosurgical instrument connectable to the radio frequency power source and the fluid source, the electrosurgical instrument to provide the fluid from the fluid source and the radio frequency power from the power source to treat the tissue; and

a control apparatus to provide a fluid flow rate of the fluid in relation to a power level of the radio frequency power.

57. The system of claim 56, wherein:

the control apparatus comprises a microprocessor and a memory.

58. The system of claim 57 further comprising:

a pump.

59. The system of claim 58, wherein:

the pump, the memory, the microprocessor and the power source are contained in a single housing.

60. The system of claim 59, wherein:

the housing further contains the fluid source.

61. A system for treating tissue comprising:

a radio frequency power source to provide radio frequency power;

a fluid source to provide a fluid;

an electrosurgical instrument connectable to the radio frequency power source and the fluid source, the electrosurgical instrument to provide the fluid from the fluid source and the radio frequency power from the power source to treat the tissue; and

a control apparatus to adjust a fluid flow rate of the fluid based upon a power level of the radio frequency power.

62. The system of claim 61, wherein:

the control apparatus comprises a microprocessor.

63. The system of claim 62 further comprising:

a pump.

64. The system of claim 63, wherein:

the pump, the microprocessor and the power source are contained in a single housing.

65. The system of claim 64, wherein:

the housing further contains the fluid source.