System and method for tissue ablation

• US 20050107781A1
• Filed: 11/18/2004
• Published: 05/19/2005
• Est. Priority Date: 11/18/2003
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Ostrovsky, Isaac, McIntyre, Jon T.
• Granted Patent: US 7,306,595 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 18/1442 Probes having pivoting end effectors, e.g. forceps
• 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 18/1815 using microwaves
• CPC Class Codes: A61B 2018/00273 Anchoring means for temporary attachment of a device to tissue
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/143 multiple needles
• CPC Class Codes: A61B 2018/1432 curved
• CPC Class Codes: A61B 2018/1435 Spiral
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/1475 Electrodes retractable in or deployable from a housing

Abstract

A tissue ablation device comprises first and second electrodes of opposite polarities, the first electrode being mounted to a first elongated member for movement relative to the second electrode for separation therefrom by a desired distance. A method of ablating a tissue comprises inserting first and second electrodes to desired initial positions relative to a tissue mass to be ablated and applying electrical energy to the first and second electrodes to ablate a first portion of tissue between the first and second electrodes in combination with the step of applying electrical energy to desired second positions separated from the desired initial positions by a distance selected to transfer electrical energy around the first portion of tissue through a second portion of tissue to be ablated, the second portion of tissue surrounding the first portion of tissue.

Claims

1. A tissue ablation device comprising first and second electrodes of opposite polarities, the first electrode being mounted to a first elongated member for movement relative to the second electrode for separation therefrom by a desired distance.

2. The device according to claim 1, wherein the first electrode includes a first array of electrodes and wherein the second electrode includes a second array of electrodes, the first array of electrodes being deployable from the first elongated member from an insertion configuration received therein, through surrounding tissue to a deployed configuration wherein ends of the electrodes of the first electrodes are separated from the first elongated member.

4. The device according to claim 1, wherein the first electrode moves relative to the second electrode along an axis substantially parallel to an axis of a second elongated member to which the second electrode is coupled.

5. The device according to claim 4, wherein the first electrode moves relative to the second electrode along the axis of the second elongated member

6. The device according to claim 5, wherein the desired distance is adjustable between a minimum distance corresponding to a thickness of insulative material located between the first and second electrodes and a maximum distance.

7. The device according to claim 1, wherein the first elongated member extends from a tissue penetrating distal end to a proximal end which, when the distal end is in an operative position within the body, remains outside the body, and wherein the second electrode is coupled to a second elongated member.

8. The device according to claim 7, wherein the second elongated member receives a proximal portion of the first elongated member within a lumen extending therethrough.

9. The device according to claim 8, wherein the first and second elongated members, when in an insertion configuration with the distance separating the first and second electrodes at a minimum, form a substantially continuous outer surface with a perimeter of a distal portion of the first elongated member substantially conforming to a perimeter of a distal end of the second elongated member.

10. The device according to claim 9, wherein the first electrode comprises a first band of conductive material extending around the distal portion of the first elongated member and the second electrode comprises a second band of conductive material extending around a distal portion of the second elongated member.

11. The device according to claim 10, wherein, when in the insertion configuration, the first and second electrodes are separated from one another by an insulative material forming one of a proximal end of the distal portion of the first elongated member and a distal end of the second elongated member.

12. The device according to claim 9, wherein a proximal portion of the first elongated member is formed of a conductive material and wherein the proximal portion of the first elongated member is electrically coupled to the first electrode and is insulated with respect to an inner surface of the second elongated member.

13. The device according to claim 12, wherein the second elongated member is formed of substantially electrically insulative material with a conductor mounted therein and extending therewithin from the proximal end of the second elongated member to the second electrode.

14. The device according to claim 7, wherein the first and second elongated members are mounted side by side substantially parallel to one another.

15. The device according claim 1, further comprising an impedance monitoring element measuring an impedance of tissue adjacent to one of the first and second electrodes.

16. The device according to claim 1, wherein the second electrode forms at least a portion of a clamp member and wherein the first elongated member includes a tissue penetrating distal tip, the first elongated member and the clamp member being movable independently of one another.

18. The device according to claim 1, wherein the first electrode comprises a first array of electrodes and the second electrode comprises a second array of electrodes, the first and second electrodes being substantially identical to one another.

19. The device according to claim 18, wherein the first elongated member is received within a second elongated member with the second array of electrodes being mounted to the second elongated member, the first and second elongated members being received within a cannula having a tissue penetrating distal tip.

20. The device according to claim 19, wherein the first array of electrodes includes a first plurality of tines which, when in a deployed configuration, extend radially outward from the first elongated member and the second array of electrodes includes a second plurality of tines which, when in the deployed configuration, extend radially outward from the second elongated member.

21. The device according to claim 20, wherein the first elongated member includes a reduced diameter portion which, when the first and second elongated members are received within the cannula, receives the second array of electrodes.

22. The device according to claim 18, wherein selected portions of the tines of the first array are coated with an electrically insulative material.

23. The device according to claim 18, wherein the tines of each of the first and second arrays, when in a deployed configuration, extend distally from proximal ends coupled to the respective one of the first and second elongated members, curving radially outward therefrom to distal ends, the distal ends of the tines of the first and second arrays being located along first and second circles, with a diameter of the first circle being substantially equal to that of the second circle.

24. A tissue ablation device comprising at least three electrodes mounted to an elongated member, each of the electrodes being electrically coupled to a corresponding electrical conductor, each of the conductors extending through the elongated member to a proximal end thereof for selective coupling to a source of electrical energy so that any desired combination of electrodes may be energized to ablate selected portions of tissue.

25. A method of ablating a tissue comprising:

inserting first and second electrodes to desired initial positions relative to a tissue mass to be ablated;

applying electrical energy to the first and second electrodes to ablate a first portion of tissue between the first and second electrodes;

applying electrical energy to desired second positions separated from the desired initial positions by a distance selected to transfer electrical energy around the first portion of tissue through a second portion of tissue to be ablated, the second portion of tissue surrounding the first portion of tissue.

26. The method according to claim 25, further comprising the steps of, before ablating the first portion of tissue, deploying the first and second electrodes into tissue and then moving the first and second electrodes toward one another to compress the first portion of tissue.

27. The method according to claim 25, further comprising the step of, after ablating the first portion of tissue, moving the first and second electrodes to the desired second positions.

28. The method according to claim 25, further comprising the step of, after ablating the first portion of tissue, energizing at least one third electrode separated from both the first and second electrodes, to ablate the second portion of tissue.

29. The method according to claim 28, wherein the step of energizing at least one third electrode includes energizing a fourth electrode separated from the first, second and third electrodes to ablate the second portion of tissue.

30. The method according to claim 29, wherein the first, second, third and fourth electrodes are mounted on an elongated member with the first and second electrodes being located between the third and fourth electrodes.

31. The method according to claim 25, wherein one of the first and second electrodes comprises an array of tines.

32. The method according to claim 25, further comprising measuring an impedance of tissue to determine when a desired degree of ablation has been achieved.

33. The method according to claim 32, further comprising terminating the application of electrical energy to the first portion of tissue when the impedance thereof exceeds a first predetermined value.

34. The method according to claim 25, wherein the step of moving at least one of the first and second electrodes away from the other of the first and second electrodes includes moving both the first and second electrodes substantially equal distances from a centerline midway therebetween to substantially center the first portion of tissue therebetween.

35. The method according to claim 25, wherein a distance between the first and second electrodes before application of electrical energy to the first portion of tissue is selected so that a diameter of the first portion of tissue is a maximum along a centerline midway between the first and second electrodes.