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

• US 7,169,144 B2
• Filed: 10/31/2003
• Issued: 01/30/2007
• Est. Priority Date: 07/07/1998
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Goetz, Steven M., Christopherson, Mark A., Hoey, Michael F.
• Primary Examiner(s): PEFFLEY, MICHAEL F
• Application Number:
  US10/699,548
• Publication Number:
  US 20040092926A1
• Time in Patent Office: 1,187 Days
• Field of Search: 606/1, 606 32- 34, 606/41, 606 45- 50, 607/101, 607/102, 600/424
• 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. A system for ablating tissue, comprising:

a surgical instrument including an ablation element for delivery of an ablating energy to the tissue;

a RF generator coupled to the surgical instrument to deliver ablating energy to the ablation element;

a memory chip coupled to the surgical instrument and storing predetermined time limit information for at least one operating parameter of the surgical instrument; and

a processor for receiving the predetermined time limit information for the at least one operating parameter and increasing a current value of the operating parameter after the predetermined time limit has elapsed.

2. The system of claim 1, wherein the memory chip is programmed with a second operating parameter including the number of times the surgical instrument is used and the processor is adapted to limit the number of times the surgical instrument is used based upon the second operating parameter.

3. The system of claim 1, wherein the operating parameter relates to the delivery of ablating energy.

4. The system of claim 3, wherein the processor is adapted to limit the amount of the ablating energy delivered to the surgical instrument based upon the operating parameter.

5. The system of claim 3, wherein the processor is programmed to limit the total amount of time that must expired prior to the ablating energy being delivered to the surgical instrument based upon the operating parameter.

6. The system of claim 1, wherein the processor is programmed to establish a time limit within which the surgical instrument must be used.

7. The system of claim 1, wherein the memory chip is pre-programmed.

8. The system of claim 1, wherein the memory chip is a microchip.

9. The system of claim 1, wherein the memory chip is located in a connector used to couple the surgical instrument to the processor.

10. The system of claim 1, wherein the surgical instrument further includes a temperature sensor for sensing a temperature.

11. The system of claim 10, wherein the operating parameter relates to temperature.

12. The system of claim 1, further comprising a source of conductive fluid selectively providing conductive fluid to the tissue.

13. The system of claim 12, wherein the operating parameter relates to fluid flow.

14. The system of claim 1, wherein the memory chip is adapted to provide a second operating parameter and the second operating parameter is an identifier unique to the surgical instrument.

15. A system for ablating tissue, comprising:

a surgical instrument including an ablation element for delivery of an ablating energy to the tissue;

a RF generator coupled to the surgical instrument to deliver ablating energy to the ablation element; and

an identifying means coupled to the surgical instrument and the RF generator, the identifying means programmed to provide at least one predetermined time limit designating an elapsed time required prior to changing an identifying characteristic of the surgical instrument to a non-zero value.

16. The system of claim 15, wherein the identifying characteristic is an operating parameter.

17. The system of claim 16, wherein the identifying means is configured to further provide a second operating parameter used to limit the number of times the surgical instrument is used.

18. The system of claim 16, wherein the operating parameter relates to the delivery of ablating energy.

19. The system of claim 18, wherein the identifying means is programmed to establish a time limit and initiate delivery of the ablating energy to the surgical instrument upon expiration of the time limit.

20. The system of claim 18, wherein the operating parameter is used to limit the total amount of time the ablating energy is delivered to the surgical instrument.

21. The system of claim 16, wherein the identifying means is configured to further provide a second operating parameter used to limit the amount of time within which the surgical instrument must be used.

22. The system of claim 15, wherein the identifying means is a memory chip.

23. The system of claim 22, wherein the memory chip is pre-programmed.

24. The system of claim 22, wherein the memory chip is a microchip.

25. The system of claim 15, wherein the identifying means includes a memory chip located in a connector.

26. The system of claim 15, wherein the surgical instrument further includes a temperature sensor for sensing a temperature.

27. The system of claim 26, wherein the identifying characteristic relates to temperature.

28. The system of claim 15, further comprising a source of conductive fluid selectively providing conductive fluid to the tissue.

29. The system of claim 28, wherein the identifying characteristic relates to fluid flow.

30. The system of claim 15, wherein the identifying means is configured to further provide an identifier unique to the surgical instrument.

31. A method of treating tissue by ablation, the method comprising:

providing an RF generator for the delivery of an ablating energy;

connecting a surgical instrument to the RF generator, the surgical instrument comprising an ablation element for delivery of the ablating energy to tissue and a memory chip storing a predetermined time limit for an operating parameter;

placing the surgical instrument in contact with tissue to be ablated;

delivering the operating parameter from the memory chip to the RF generator;

delivering ablating energy from the RF generator through the surgical instrument to tissue to be ablated based upon the operating parameter;

changing a value of the operating parameter following the elapse of the predetermined time limit while maintaining the surgical instrument relative to the tissue; and

operating the surgical instrument to continue ablating the tissue.

32. The method of claim 31, wherein the memory chip delivers a second operating parameter that limits the number of times ablating energy is delivered from the RF generator through the surgical instrument.

33. The method of claim 31, wherein the memory chip delivers a second operating parameter that limits the total amount of time ablating energy is delivered from the RF generator through the surgical instrument.

34. The method of claim 31, further comprising establishing a time limit within which the surgical instrument may be used to deliver ablating energy.

35. The method of claim 31, wherein the operating parameter limits the delivery of ablating energy from the RF generator through the surgical instrument.

36. The method of claim 31, wherein the memory chip is pre-programmed.

37. The method of claim 31, wherein the memory chip is a microchip.

38. The method of claim 31, wherein the memory chip is located in a connector used to connect the surgical instrument to the RF generator.

39. The method of claim 31, wherein the surgical instrument further comprises a temperature sensor.

40. The method of claim 39, wherein the operating parameter limits the delivery of ablating energy from the RF generator based on temperature.

41. The method of claim 31, further comprising selectively providing conductive fluid to the tissue to be ablated from a source of conductive fluid.

42. The method of claim 41, further comprising controlling the flow of fluid from the source of conductive fluid to the tissue based upon the operating parameter.

43. The method of claim 31, wherein the memory chip delivers a second operating parameter that is an identifier unique to the surgical instrument.