Systems and methods for electrosurgical tissue treatment

• US 20030028189A1
• Filed: 06/27/2002
• Published: 02/06/2003
• Est. Priority Date: 08/11/1998
• Status: Active Grant

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Woloszko, Jean, Dahla, Robert H., Gutierrez, Irma, Baker, Michael A., Kahlon, Hardev, Nguyen, Cindy Truc, Villaruel, Adelina
• Granted Patent: US 7,435,247 B2
• Time in Patent Office: Days
• US Class Current: 606/45
• CPC Class Codes: A61B 18/042 using additional gas becoming plasma
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 18/148 having a short, rigid shaft for accessing the inner body transcutaneously, e.g. for neurosurgery or arthroscopy
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00583 Coblation, i.e. ablation using a cold plasma
• CPC Class Codes: A61B 2018/1213 creating an arc
• CPC Class Codes: A61B 2018/1472 for use with liquid electrolyte, e.g. virtual electrodes

Abstract

Systems and methods are provided for applying a high frequency voltage in the presence of an electrically conductive fluid to create a relatively low-temperature plasma for ablation of tissue adjacent to, or in contact with, the plasma. In one embodiment, an electrosurgical probe or catheter is positioned adjacent the target site so that one or more active electrode(s) are brought into contact with, or close proximity to, a target tissue in the presence of electrically conductive fluid. High frequency voltage is then applied between the active electrode(s) and one or more return electrode(s) to non-thermally generate a plasma adjacent to the active electrode(s), and to volumetrically remove or ablate at least a portion of the target tissue. The high frequency voltage generates electric fields around the active electrode(s) with sufficient energy to ionize the conductive fluid adjacent to the active electrode(s). Within the ionized gas or plasma, free electrons are accelerated, and electron-atoms collisions liberate more electrons, and the process cascades until the plasma contains sufficient energy to break apart the tissue molecules, causing molecular dissociation and ablation of the target tissue.

Claims

1. A system for applying electrical energy to tissue at a target site comprising:

an electrosurgical instrument having a shaft with a proximal end, a distal end and a tissue treatment surface at the distal end, the tissue treatment surface including one or more active electrodes, a plurality of spacers extending away from the tissue treatment surface;

a return electrode;

a fluid source for providing electrically conductive fluid between the return electrode and the active electrodes; and

one or more connectors coupled to the active electrodes for connecting the active electrodes to a high frequency power supply.

2. The system of claim 1 wherein the spacers are rigid.

3. The system of claim 1 wherein the spacers are flexible.

4. The system of claim 1 wherein the spacers extend beyond a distal end of the electrodes by a distance between 0.025 mm to 0.25 mm.

5. The system of claim 1 further comprising an insert located in a distal end of the device and where the spacers protrude from the insert through the tissue treatment surface.

9. The system of claim 1 further comprising an insert located in the vent and where the spacers protrude from the insert through the tissue treatment surface.

11. The system of claim 9 wherein the electrodes are recessed from the tissue treatment surface.

12. The system of claim 9 wherein the electrodes have at least one edge comprising a reduced surface area, the edge adapted to increase density of current flowing through the electrode.

6. A system for applying electrical energy to tissue at a target site comprising:

an electrosurgical instrument having a shaft with a proximal end, a distal end and a tissue treatment surface at the distal end, the tissue treatment surface including one or more active electrodes, and a vent located in the tissue treatment surface, the vent adapted to facilitate heat flow from the target site through the vent;

a return electrode;

a fluid source for providing electrically conductive fluid between the return electrode and the active electrodes; and

one or more connectors coupled to the active electrodes for connecting the active electrodes to a high frequency power supply.

7. The system of claim 6 further including a plurality of spacers extending away from the tissue treatment surface.

8. The system of claim 6 wherein the vent is tapered and extends through an end of the instrument opposite to the tissue treatment surface.

10. A system for applying electrical energy to tissue at a target site comprising:

an electrosurgical instrument having a shaft with a proximal end, a distal end and a tissue treatment surface at the distal end, the tissue treatment surface including an electrode support member comprising a plurality of interconnected chambers containing one or more active electrodes;

a return electrode; and

a fluid source for providing electrically conductive fluid between the return electrode and the active electrodes, wherein one or more connectors coupled to the active electrodes for connecting the active electrodes to a high frequency power supply.