Electrosurgical system

• US 6,241,723 B1
• Filed: 04/21/1999
• Issued: 06/05/2001
• Est. Priority Date: 10/15/1997
• Status: Expired due to Term

• Current Assignee: Microline Surgical, Inc. (Hoya Corporation), Surginetics, Inc.
• Original Assignee: Team Medical, LLC
• Inventors: Olichney, Michael D., Heim, Warren P., Brassell, James L.
• Primary Examiner(s): PEFFLEY, MICHAEL F
• Application Number:
  US09/295,723
• Time in Patent Office: 776 Days
• Field of Search: 606/32-35, 606/37-42, 128/898
• US Class Current: 606/34
• 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 2018/00005 Cooling or heating of the probe or tissue immediately surrounding the probe
• CPC Class Codes: A61B 2018/00083 low, i.e. electrically insulating
• CPC Class Codes: A61B 2018/00101 low, i.e. thermally insulating
• CPC Class Codes: A61B 2018/0066 without feedback, i.e. open loop control

Abstract

An electrosurgical system is disclosed that applies electrical energy to obtain a predetermined surgical effect, while also reducing eschar deposits on a working surface of an electrosurgical instrument, producing an eschar deposit which is easily removed from the working surface and/or facilitating removal of eschar deposits during a cleaning procedure. Such benefits may be realized by providing a negative bias on the working surface relative to a return path to source during electrosurgical procedures and/or during a cleaning procedure which may include contacting the working surface with an electrically conductive liquid. To reduce smoke generation at a surgical site, the electrosurgical instrument may comprise a metal body having an outer insulating layer to reduce thermal/electrical discharge from non-functional portions of the instrument. An insulating layer having a thermal conductance of about 1.2 W/cm²° K and a dielectric withstand strength of at least about 50 volts may be employed. Such insulating layer may advantageously comprise silicon and/or carbon. The metal body may be provided to have a thermal conductivity of at least about 0.35 W/cm° K, and may advantageously comprise a metal selected from the group: gold, silver, aluminum, and copper. Heat sink means may be included in various embodiments to establish a thermal gradient away from functional portions of the instrument (i.e., by removing heat from the metal body).

Claims

1. An electrosurgical apparatus comprising:

means for providing a negative-biasing signal component;

means for combining said negative-biasing signal component with a radio frequency signal component to provide an electrosurgical signal; and

,

an electrosurgical instrument having a metal body for carrying the electrosurgical signal and an outer insulating layer positioned over at least a portion of said metal body, wherein said electrosurgical signal defines a negative mean voltage bias at the electrosurgical instrument relative to an electrosurgical return path device.

2. An apparatus as recited in claim 1 further comprising:

an electrosurgical generator for providing said radio frequency signal component.

3. An apparatus as recited in claim 2, wherein said means for providing utilizes said radio-frequency signal component to generate said negative biasing signal component.

4. An apparatus as recited in claim 2, said means for providing including:

an electrical energy source separate from said electrosurgical generator.

5. An apparatus as recited in claim 4, wherein said electrical energy source is selected from the group comprising:

a DC energy source, and a time-varying energy source having an operating frequency less than an operating frequency of the radio frequency electrosurgical generator.

6. An apparatus as recited in claim 4, wherein said electrical energy source comprises at least one of a direct current energy source and a time-varying energy source.

7. An apparatus as recited in claim 6, wherein said radio frequency signal component has a minimum first frequency and said negative biasing signal component has a maximum second frequency, said first frequency being greater than said second frequency, and wherein said apparatus further comprises:

at least one of a first frequency-biased blocking component and a first frequency-based shunting component to isolate said time-varying energy source from said radio frequency signal component; and

at least one of a second frequency-based blocking component and a second frequency based shunting component to isolate said electrosurgical generator from said negative-biasing signal component.

8. An as recited in claim 1, wherein said metal body has a thermal conductivity of at least about 0.35 W/cm°

K when measured at about 300°

K.

9. An apparatus as recited in claim 1, said metal body having a main body portion and a peripheral edge portion, wherein said electrosurgical signal is conveyed to tissue substantially entirely through said peripheral edge portion.

10. An apparatus as recited in claim 9, wherein said metal body comprises at least one metal selected from a group comprising:

aluminum, silver, copper and gold.

11. An apparatus as recited in claim 9, wherein an outer portion of said peripheral edge portion is not covered by the insulating layer, and wherein said instrument further comprises:

a biocompatible coating disposed on at least an outer portion of said peripheral edge portion of said metal body.

12. An apparatus as recited in claim 11, wherein said biocompatible coating includes a component selected from a group comprising:

nickel, silver, gold, chrome and titanium.

13. An apparatus as recited in claim 9, wherein said metal body comprises a metal alloy having a first component selected from a group comprising:

aluminum, silver, copper and gold; and

wherein said first component comprises at least about 50% of said metal body by weight.

14. An electrosurgical instrument as recited in claim 9, wherein said peripheral edge portion has a maximum cross-sectional thickness of no more than about one-tenth of the maximum cross-sectional thickness of the main body portion.

15. An electrosurgical instrument as recited in claim 9, wherein said peripheral edge portion has an outer extreme edge having a thickness of less than about 0.001 inches or less.

16. An electrosurgical instrument as recited in claim 1, wherein said outer insulating layer substantially covers said main body portion.

17. An electrosurgical instrument as recited in claim 1, wherein said outer insulating layer contains at least one material having a thermal conductivity of less than about 6 W/cm−

°

K when measured at about 300°

K.

18. An electrosurgical instrument as recited in claim 1, wherein said outer insulating layer has a thickness of at least about 0.01 mm.

19. An electrosurgical instrument as recited in claim 1, wherein said insulating layer has a thermal conductance of about 1.2 W/cm²−

°

K or less when measured at about 300°

K.

20. An electrosurgical instrument as recited in claim 1, wherein said outer insulating layer comprises a polymeric compound.

21. An electrosurgical instrument as recited in claim 20, wherein said polymeric compound includes at least about 10% of a first component by weight, said first component selected from a group comprising:

silicon and carbon.

22. An electrosurgical instrument as recited in claim 1, wherein said metal body includes a main body portion and a peripheral edge portion, and wherein said metal body is laterally-tapered down in cross-sectional thickness from said main body portion to said peripheral edge portion.

23. An electrosurgical instrument as recited in claim 22, wherein said peripheral edge portion has a maximum cross-sectional thickness of no more than about one-tenth of the maxium cross-section thickness of the main body portion.

24. An electrosurgical method for obtaining at least one predetermined surgical effect at a tissue site, comprising:

supplying an electrosurgical signal to an electrosurgical instrument having a metal body for carrying the electrosurgical signal and an outer insulating layer positioned over at least a portion of said metal body;

providing an electrical signal return path from said tissue site; and

conveying electrical energy to the tissue site from said working surface, wherein the metal body has a negative average voltage bias relative to the return path.

25. An electrosurgical method as recited in claim 24, said supplying step including:

combining a first signal component and a second signal component to obtain said electrosurgical signal.

26. An electrosurgical method as recited in claim 25, further comprising:

cleaning said working surface of said electrosurgical instrument, wherein said cleaning step includes;

applying an electrical cleaning signal, different from said electrosurgical signal, to said working surface.

27. An electrosurgical method as recited in claim 26, further comprising:

contacting said electrosurgical instrument with a conductive liquid;

contacting a conductive return electrode with said conductive liquid, wherein a negative voltage bias is provided at said electrosurgical instrument relative to said return electrode.

28. An electrosurgical method as recited in claim 25, said supplying step further including:

utilizing a radio frequency electrosurgical generator to generate said first signal component.

29. An electrosurgical method as recited in claim 28, said supplying step further including:

employing an electrical energy source, separate from said radio frequency electrosurgical generator, to provide said second signal component.

30. An electrosurgical method as recited in claim 29, further comprising:

utilizing at least one first frequency-biased blocking or component to isolate said electrosurgical generator from said electrical energy source;

employing at least one second-frequency biased blocking component to isolate said electrical energy source from said electrosurgical generator.

31. An electrosurgical method as recited in claim 29, wherein said electrical energy source is selected from the group comprising:

a DC energy source, and a time-varying energy source having an operating freuency less than an operating frequency of the radio frequency electrosurgical generator.

32. An electrosurgical method as recited in claim 28, said supplying step further including:

employing said first signal component to obtain said second signal component.

33. An electrosurgical method as recited in claim 32, wherein said second signal component is a DC signal.

34. An electrosurgical method as recited in claim 32, wherein said first signal component has a first frequency and said second signal component has a second frequency, said second frequency being less than said first frequency.

35. An electrosurgical method as recited in claim 34, wherein said first frequency is more than about 100 kHz and said second frequency is less than about 10 kHz.

36. The method of claim 24, wherein the negative average bias voltage exceeds about 1 volt.

37. The method of claim 36, wherein the negative average voltage bias is between about 1 and 60 volts.

38. The method of claim 24, further comprising:

applying a mist of a biocompatible substance to the tissue site during at least a portion of said conveying step.

39. The method of claim 24, wherein said metal body has a thermal conductivity of at least about 0.35 W/cm°

K. when measured at about 300°

K.

40. The method of claim 24, said metal body having a main body portion and a peripheral edge portion, wherein said electrosurgical signal is conveyed to tissue substantially entirely through said peripheral edge portion.

41. The method of claim 40, wherein said metal body comprises at least one metal selected from a group comprising:

aluminum, silver, copper and gold.

42. The method of claim 41, wherein an outer portion of said peripheral edge portion is not covered by the insulating layer, and wherein said instrument further comprises a biocompatible coating disposed on at least an outer portion of said peripheral edge portion of said metal body.

43. The method of claim 42, wherein said biocompatible coating includes a component selected from a group comprising:

nickel, silver, gold, chrome and titanium.

44. The method of claim 40, wherein said metal body comprises a metal alloy having a first component selected from a group comprising:

aluminum, silver, copper and gold; and

wherein said first component comprises at least about 50% of said metal body by weight.

45. The method of claim 40, wherein said peripheral edge portion has a maximum cross-sectional thickness of no more than about one-tenth of the maximum cross-sectional thickness of the main body portion.

46. The method of claim 40, wherein said peripheral edge portion has an outer extreme edge having a thickness of less than about 0.001 inches or less.

47. The method of claim 40, wherein said outer insulating layer substantially covers said main body portion.

48. The method of claim 24, wherein said outer insulating layer contains at least one material having a thermal conductivity of less than about 6 W/cm-°

K when measured at about 300°

K.

49. The method of claim 24, wherein said outer insulating layer has a thickness of at least about 0.01 mm.

50. The method of claim 24, wherein said insulating layer has a thermal conductance of about 1.2 W/cm²−

°

K or less when measured at about 300°

K.

51. The method of claim 50, wherein said outer insulating layer comprises a polymeric compound.

52. The method of claim 51, wherein said polymeric compound includes at least about 10% of a first component by weight, said first component selected from a group comprising:

silicon and carbon.

53. The method of claim 24, wherein said metal body includes a main body portion and a peripheral edge portion, and wherein said metal body is laterally-tapered down in cross-sectional thickness from said main body portion to said peripheral edge portion.

54. The method of claim 53, wherein said peripheral edge portion has a maximum cross-sectional thickness of no more than about one-tenth of the maximum cross-sectional thickness of the main body portion.