TISSUE ABLATION SYSTEMS

• US 20100100091A1
• Filed: 08/13/2009
• Published: 04/22/2010
• Est. Priority Date: 10/21/2008
• Status: Active Grant

• Current Assignee: Hermes Innovations, LLC
• Original Assignee: Hermes Innovations, LLC
• Inventors: Truckai, Csaba
• Granted Patent: US 8,372,068 B2
• Time in Patent Office: Days
• US Class Current: 606/33
• CPC Class Codes: A61B 18/042 using additional gas becoming plasma
• CPC Class Codes: A61B 18/1477 Needle-like probes
• 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 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• CPC Class Codes: A61B 2018/00559 Female reproductive organs
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00642 with feedback, i.e. closed loop control
• 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 2018/00898 Alarms or notifications created in response to an abnormal condition
• CPC Class Codes: A61B 2018/122 ionizing, with corona
• CPC Class Codes: A61B 2018/147 Electrodes transferring energy by capacitive coupling, i.e. with a dielectricum between electrode and target tissue
• CPC Class Codes: A61B 2090/3983 Reference marker arrangements for use with image guided surgery

Abstract

Tissue is treated using a radiofrequency power supply connected to an applicator having a chamber filled with an electrically non-conductive gas surrounded by a thin dielectric wall. A radiofrequency voltage is applied at a level sufficient to ionize the gas into a plasma and to capacitively couple the ionized plasma with the tissue to deliver radiofrequency current to ablate or otherwise treat the tissue.

Claims

1. Apparatus for delivering a radiofrequency current to tissue, said device comprising:

a body having a support end, a working end, an interior chamber, and a thin dielectric wall surrounding at least a portion of the interior chamber and having an external surface disposed at the working end;

a gas inlet connected to deliver an electrically non-conductive gas to the interior chamber;

a first electrode structure having a surface exposed to the interior chamber and/or the gas inlet;

a second electrode structure having a surface adapted to contact tissue;

a radiofrequency power supply connected to apply a radiofrequency voltage across the first and second electrode structures, wherein the voltage is sufficient to initiate a plasma in the electrically non-conductive gas within the chamber and to capacitively couple current in the plasma across the dielectric wall into tissue.

2. Apparatus as in claim 1, wherein the dielectric wall comprises a rigid material selected from the group consisting of ceramics, glass, and polymers.

3. Apparatus as in claim 2, wherein the rigid material is formed into a tube having a cylindrical external surface.

4. Apparatus as in claim 2, wherein the dielectric wall has a thickness in the range from 0.002 in to 0.1 in.

5. Apparatus as in claim 1, wherein the dielectric wall comprises a conformable material including a silicone.

6. Apparatus as in claim 5, wherein the dielectric wall has a thickness in the range from 0.03 in to 0.004 in.

7. Apparatus as in claim 5, wherein the conformable material is formed into an inflatable structure.

8. Apparatus as in claim 5, further comprising a frame which supports the conformable material.

9. Apparatus as in claim 8, wherein the frame can be expanded and contracted to open and close the dielectric wall.

10. Apparatus as in claim 1, further comprising a shaft connected to the support end of the body.

11. Apparatus as in claim 10, wherein the shaft has a lumen which extends the gas inlet to deliver the electrically non-conductive gas to the chamber of the body.

12. Apparatus as in claim 11, wherein the shaft includes at least a second lumen for removing the electrically non-conductive gas from the chamber of the body, whereby a continuous flow of electrically non-conductive gas through the chamber can be maintained.

13. Apparatus as in claim 12, wherein the first electrode is at least partly in the first lumen.

14. Apparatus as in claim 13, wherein the second electrode is disposed at least partly over an exterior surface of the shaft.

15. Apparatus as in claim 1, wherein the interior chamber has a volume in the range from 0.01 ml to 100 ml.

16. Apparatus as in claim 1, wherein the radiofrequency power supply is configured to deliver a voltage in the range from 500 V (rms) to 2500 V (rms).

17. An electrosurgical ablation probe comprising:

a shaft having a proximal end and a distal end;

an energy applicator disposed near the distal end of the shaft, wherein the applicator includes a dielectric wall having an interior surface and an exterior surface;

a gas flow passage within the shaft for delivering a gas to the interior surface of the dielectric wall of the applicator;

a first electrode structure which is exposed to gas within the gas flow passage; and

a second electrode structure on an exterior surface of the shaft;

wherein application of a radiofrequency voltage across the first and second electrodes will initiate a plasma in an electrically non-conductive gas in the flow passage when the exterior surface of the dielectric wall engages tissue which also contacts the second electrode structure.

18. A probe as in claim 17, wherein the dielectric wall comprises a rigid material selected from the group consisting of ceramics, glass, and polymers.

19. A probe as in claim 18, wherein the rigid material is formed into a tube having a cylindrical external surface.

20. A probe as in claim 18, wherein the dielectric wall has a thickness in the range from 0.002 in to 0.1 in.

21. A probe as in claim 17, wherein the dielectric wall comprises a conformable material including a silicone.

22. A probe as in claim 21, wherein the dielectric wall has a thickness in the range from 0.03 in to 0.004 in.

23. A probe as in claim 21, wherein the conformable material is formed into an inflatable structure.

24. A probe as in claim 21, wherein the applicator comprises a frame which supports the conformable material.

25. A probe as in claim 24, wherein the frame can be expanded and contracted to open and close the dielectric wall.

26. A probe as in claim 17, wherein the shaft is connected to a proximal end of the energy applicator.

27. A probe as in claim 26, wherein the gas flow passage comprises a lumen which extends the length of the shaft to deliver the electrically non-conductive gas to the chamber of the body.

28. A probe as in claim 27, wherein the shaft includes at least a second lumen for removing the electrically non-conductive gas from the chamber of the body, whereby a continuous flow of electrically non-conductive gas through the chamber can be maintained.

29. A probe as in claim 28, wherein the first electrode is at least partly in the first lumen.

30. Apparatus as in claim 29, wherein the first electrode is disposed at least partly within the applicator.

31. A probe as in claim 17, wherein the applicator has an interior chamber forming a portion of the gas flow passage with a volume in the range from 0.01 ml to 100 ml.

32. A probe as in claim 17, wherein the electrodes are configured to be driven by a voltage in the range from 500 V (rms) to 2500 V (rms).