Surgical gas plasma ignition apparatus and method

• US 6,213,999 B1
• Filed: 09/22/1997
• Issued: 04/10/2001
• Est. Priority Date: 03/07/1995
• Status: Expired due to Term

• Current Assignee: Covidien AG (Medtronic Plc)
• Original Assignee: Sherwood Services AG
• Inventors: Platt, Robert C. Jr., Bek, Robin Badih
• Primary Examiner(s): Shay, David M.
• Application Number:
  US08/934,843
• Time in Patent Office: 1,296 Days
• Field of Search: 606/27, 606/34-40
• US Class Current: 606/27
• CPC Class Codes: A61B 18/042 using additional gas becoming plasma
• CPC Class Codes: A61B 2018/1213 creating an arc

Abstract

An apparatus and method for igniting plasma in a surgical system is disclosed. A corona discharge is generated on a surgical handpiece which is used to ignite a plasma arc for surgical operations. The advantages include greater reliability and repeatability of plasma arc ignition. The apparatus comprises a handpiece incorporating an active electrode, a passage for ionizable gas, and a corona return electrode. The corona return electrode has a terminus on the holder and near the distal end of the holder. The corona return electrode is electrically connected to the return path of the electrosurgical generator. A non-uniform electric field is generated between the active electrode and the corona return electrode of sufficient strength so that a corona is formed near the active electrode. A separate return electrode may be on the patient, or the apparatus may be configured for bipolar electrosurgical operation by carrying the return electrode on the handpiece. A dielectric material separates the active electrode and the corona return electrode. There is substantially capacitive coupling between the active electrode and the corona return electrode. There is substantially resistive coupling between the active electrode and the return electrode.

Claims

1. A corona ignition system for initiating a plasma arc in an electrosurgical system, the corona ignition system comprising:

a source of high frequency electrical energy having a terminal of active potential and a terminal of return potential;

a holder having a distal end from which the plasma arc emanates;

an active electrode carried in the holder and electrically in circuit with the terminal of active potential;

a corona return electrode carried in the holder and electrically in circuit with the terminal of return potential, the corona return electrode coupled to the active electrode directly adjacent to the distal end of the holder by substantially capacitive means such that a corona discharge is formed adjacent the distal end of the holder; and

a dielectric member disposed between the active electrode and the corona return electrode.

3. The corona ignition system of claim 1 wherein the corona return electrode is at least partially in the form of a conductive mesh.

4. The corona ignition system of claim 1 wherein the corona return electrode is at least partially in the form of a conductive foil.

5. The corona ignition system of claim 1 wherein a portion of the active electrode is in close proximity to the corona return electrode.

6. The corona ignition system of claim 1 wherein a movable mount which is accessible to the surgeon positions the active electrode relative to the corona return electrode.

7. The corona ignition system of claim 1 wherein the passage is a tube associated with the holder and the corona return electrode is a wire carried by the tube.

8. The corona ignition system of claim 1 wherein the passage is a tube associated with the holder and the active electrode is substantially centered to be coaxially within at least a portion of the tube.

9. The corona ignition system of claim 8 wherein and corona return electrode is thin hollow cylinder carried coaxially on the exterior surface of the tube.

10. The corona ignition system of claim 1 wherein the passage is made of a dielectric material.

11. The corona ignition system of claim 10 wherein the corona return electrode is at least partially in the form of a conductive deposit on the tube.

12. The corona ignition system of claim 1 wherein the corona return electrode is a conductor supported by the passage and the corona return electrode is encased at least partially by a wall of the passage.

13. The corona ignition system of claim 6 wherein the active electrode and the passage are coaxially disposed relative to one another over at least a portion of the tube.

2. A corona ignition system for initiating a plasma arc to be applied by a surgeon to the tissue or bodily fluids of a patient, the corona ignition system comprising:

a holder for the surgeon to control during application of the plasma arc, the holder having a distal end to point to the patient;

a regulated source of ionizable gas;

a passage through the holder and connected proximally with the regulated source of ionizable gas so that it may pass therethrough;

an active electrode in the passage extending distally from the distal end, the active electrode and the regulated ionizable gas are in contact;

a source of high frequency electrical energy connected to the active electrode;

a return connected to the source of high frequency electrical energy, the return being in circuit with the tissue or bodily fluids;

a corona return electrode located directly adjacent to the distal end and radially spaced from the active electrode, the corona return electrode connected to the source of high frequency electrical energy to establish an electrical field with the active electrode; and

a dielectric member near the distal end, the dielectric member between the active electrode and corona return electrode, and between the ionizable gas and corona return electrode, enabling a corona to be created around the active electrode enhancing initiation of the plasma arc.

14. A method of using a corona ignition system for initiating a plasma arc in an electrical system, the plasma arc emanating from a distal end of a holder, the holder having an active electrode, the method comprising the steps of:

positioning a corona return electrode adjacent the distal end of the holder;

positioning a dielectric barrier between the active electrode and the corona return electrode;

electrically coupling the active electrode and the corona return electrode directly adjacent to the distal end of the holder by substantially capacitive means;

generating a corona near the distal end of the holder; and

using the corona to aid the initiation of the plasma arc.