Tissue ablation apparatus and method

• US 20030212394A1
• Filed: 05/10/2002
• Published: 11/13/2003
• Est. Priority Date: 05/10/2001
• Status: Active Grant

• Current Assignee: AngioDynamics, Inc.
• Original Assignee: RITA Medical Systems LLC (AngioDynamics, Inc.)
• Inventors: Balbierz, Daniel J., Liang, Jessica, Pearson, Rob, Lee, Kee S., Getaneh, Martha, Daniel, Steve A.
• Granted Patent: US 7,160,296 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1477 Needle-like probes
• CPC Class Codes: A61B 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00654 with individual control of each of a plurality of energy emitting elements
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00714 Temperature
• CPC Class Codes: A61B 2018/00791 Temperature
• CPC Class Codes: A61B 2018/00797 measured by multiple temperature sensors
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/143 multiple needles
• 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

Abstract

A tissue-ablation method and apparatus are disclosed. The apparatus includes a plurality of RF ablation electrodes, and a plurality of sensor elements, each movable from retracted to deployed positions in a tissue to be ablated. A control device in the apparatus is operatively connected to the electrodes for supplying an RF power to the electrodes, to produce tissue ablation that advances from individual-electrode ablation regions to fill a combined-electrode ablation volume. The control device is operatively connected to the sensor elements for determining the extent of ablation in the regions of the sensor elements. The supply of RF power to the electrodes can thus be regulated to control the level and extent of tissue ablation throughout the combined-electrode volume. The electrodes are preferably hollow-needle electrodes through which liquid can be infused into the tissue, also under the control of the control unit, to modulate and optimize tissue ablation.

Claims

1. A tissue-ablation apparatus comprising:

(a) an elongate delivery device having a lumen terminating at a distal end,

(b) a plurality of electrodes carried in said device for movement between retracted positions at which the electrodes are disposed within the device'"'"'s lumen, and deployed positions at which the electrodes are deployed from said distal end at a plurality of arcuate, laterally extending, angularly spaced positions,

(i) each deployed electrode defining an individual-electrode ablation volume which is proximate that electrode when an RF current is initially applied to that electrode, with such deployed in tissue, and

(ii) with continued application of RF current to the electrodes causing the individual-electrode ablation volumes to grow and merge with each other to form a combined-electrode ablation volume,

(c) a plurality of elongate sensor elements carried in said device for movement between retracted positions at which the sensor elements are disposed within the device'"'"'s lumen, and deployed positions at which the sensor are deployed from said distal end at a plurality of angularly spaced positions within the volume corresponding to the combined-electrode ablation volume, and

(d) a control device operatively connected to said electrodes and to said sensor elements for (i) supplying a RF power to said electrodes, with such deployed in tissue, to produce tissue ablation that advances from the individual-electrode ablation volumes to fill the combined-electrode ablation volume, and (ii) determining the extent of ablation in the region of the sensor elements,

wherein the supply of RF power to said electrodes can be regulated to control the level and extent of tissue ablation throughout the combined-electrode ablation volume.

2. The apparatus of claim 1, wherein electrodes and sensor elements are operatively connected for movement as a unit from their retracted to their deployed positions.

3. The apparatus of claim 1, wherein said electrodes are movable from their retracted to their retracted and deployed positions independent of the movement of the sensor elements from their retracted to deployed positions.

4. The apparatus of claim 1, wherein each sensor element, in its deployed state, is disposed outside of the initial individual-electrode ablation volumes, approximately midway between pair of adjacent electrodes in their deployed state.

5. The apparatus of claim 1, wherein sensor elements are conductive wires, and the control device is operable to determine the tissue impedance in the regions of said wires, as a measure of extent of ablation in the region of the sensor elements.

6. The apparatus of claim 1, wherein sensor elements have thermal sensors, and the control device is operable to determine tissue temperature in the regions of the thermal sensors, as a measure of the extent of ablation in the region of the sensor elements.

7. The apparatus of claim 1, wherein the sensor elements are optical fibers, and the control device is operable to determine optical properties in the regions of the fibers, as a measure of the extent of ablation in the region of the sensor elements.

8. The apparatus of claim 1, wherein said electrodes are hollow-needle electrodes, allowing liquid to be injected through said electrodes into tissue, with the electrodes deployed in tissue.

9. The apparatus of claim 8, which is designed to allow controlled fluid flow through each electrode individually.

10. The apparatus of claim 8, wherein each electrode has a plurality of infusion ports along its distal end regions, and is covered by a sheath that is axially movable between deployment and infusion positions at which the infusion ports are covered and exposed, respectively.

11. The apparatus of claim 8, wherein each electrode has a plurality of infusion ports along its distal end regions, and is covered by a sheath including a fixed gap.

12. The apparatus of claim 1, wherein said control device includes a display function for displaying to a user the extent of ablation of in the regions of the sensor elements, and an adjustable power function by which the user can adjust the RF power applied to said electrodes.

13. The apparatus of claim 1, wherein said control device is operable to adjust the power level applied to said electrodes in response to information received from said sensor elements relating to the extent of ablation in the regions of the sensor elements.

14. The apparatus of claim 1, wherein said electrodes are hollow-needle electrodes, allowing liquid to be injected through said electrodes into tissue, with the electrodes deployed in tissue, and said control device includes a display function for displaying to a user the extent of ablation of in the regions of the sensor elements, and an adjustable fluid-control function by which the user can adjust the rate of liquid supplied to the individual electrodes.

15. The apparatus of claim 1, wherein said electrodes are hollow-needle electrodes, allowing liquid to be injected through said electrodes into tissue, with the electrodes deployed in tissue, and said control device is operable to control the rate of liquid flow through the electrodes in response to information received from said sensor elements relating to the extent of ablation in the regions of the sensor elements.

16. The apparatus of claim 1, wherein said electrodes, when deployed, are positioned near the center of the faces of a platonic solid that defines a desired combined-electrode ablation volume.

17. The apparatus of claim 16, wherein the sensor elements, when deployed, are positioned near vertices of the platonic solid.

18. The apparatus of claim 16, for ablating a substantially spherical volume that circumscribes a pyramid, which has four electrodes that are positioned near the center of the faces of the pyramid when deployed, and four sensors which are placed near the vertices of the pyramid when deployed.

19. The apparatus of claim 1, which further includes a body-surface electrode adapted to be applied to the surface of a patient, and the control device is operable to apply RF power between the plurality of electrodes and the body-surface electrodes.

20. The apparatus of claim 1, wherein said apparatus is configured to operate in a bipolar mode.

21. The apparatus of claim 1, wherein all or a portion of the elongate delivery device distal end is plastic.

22. The apparatus of claim 1, wherein all or a portion of the elongate delivery device distal end is elastomer.

23. The apparatus of claim 1, wherein said elongate delivery device is configured to have a radiused or smooth inner leading edge.