Electrosurgical generator and system

• US 6,306,134 B1
• Filed: 10/16/1998
• Issued: 10/23/2001
• Est. Priority Date: 06/23/1995
• Status: Expired due to Term

• Current Assignee: Gyrus Medical Incorporated (Olympus Corporation)
• Original Assignee: Gyrus Medical Incorporated (Olympus Corporation)
• Inventors: Goble, Nigel Mark, Goble, Colin Charles Owen
• Primary Examiner(s): Shay, David M.
• Application Number:
  US09/173,728
• Time in Patent Office: 1,103 Days
• Field of Search: 606/40-52, 606/34
• US Class Current: 606/42
• CPC Class Codes: A61B 18/082 Probes or electrodes therefor
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• 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 18/1482 having a long rigid shaft for accessing the inner body transcutaneously in minimal invasive surgery, e.g. laparoscopy
• CPC Class Codes: A61B 18/1485 having a short rigid shaft for accessing the inner body through natural openings
• CPC Class Codes: A61B 18/149 bow shaped or with rotatable body at cantilever end, e.g. for resectoscopes, or coagulating rollers
• 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 2017/00482 with a code
• CPC Class Codes: A61B 2018/00178 Electrical connectors
• CPC Class Codes: A61B 2018/00505 Urinary tract
• CPC Class Codes: A61B 2018/00589 Coagulation
• CPC Class Codes: A61B 2018/00625 Vaporization
• CPC Class Codes: A61B 2018/00666 using a threshold value
• CPC Class Codes: A61B 2018/00755 Resistance or impedance
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/00892 Voltage
• CPC Class Codes: A61B 2018/00988 Means for storing information, e.g. calibration constants, or for preventing excessive use, e.g. usage, service life counter
• CPC Class Codes: A61B 2018/1213 creating an arc
• CPC Class Codes: A61B 2018/126 : bipolar
• 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 2018/1472 : for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2018/162 : located on the probe body
• CPC Class Codes: A61B 2018/1861 : with an instrument inserted into a body lumen or cavity, e.g. a catheter
• CPC Class Codes: A61M 2205/6018 : providing set-up signals for the apparatus configuration
• CPC Class Codes: A61M 2205/6027 : Electric-conductive bridges closing detection circuits, with or without identifying elements, e.g. resistances, zener-diodes

Abstract

An electrosurgical system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporization or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning.

Claims

1. A method of operating an electrosurgical system having at least a tissue desiccation mode and a tissue cutting or vaporisation mode, the system having a radio frequency power generator coupled to an electrode assembly having an electrode for operation in a conductive liquid, wherein the method comprises:

selecting one of the said modes;

when the desiccation mode is selected, automatically adjusting the radio frequency power supplied to the electrode assembly to maintain the conductive liquid adjacent the electrode at its boiling point for tissue desiccation without creating a vapour pocket surrounding the electrode; and

when the cutting or vaporisation mode is selected, automatically adjusting the radio frequency power supplied to the electrode to maintain a vapour pocket surrounding the electrode.

2. A method according to claim 1, wherein, in the cutting or vaporisation mode, the radio frequency power supplied to the electrode is automatically limited to prevent overheating of the electrode.

3. A method according to claim 2, wherein the radio frequency power supplied to the electrode is automatically adjusted by limiting the output voltage applied to the electrode to predetermined first and second voltage values, the first voltage value being used in the desiccation mode, and the second voltage value, which is higher than the first voltage value, being used in the curting or vaporisation mode.

4. A method according to claim 3, wherein the first and second voltage values are in the ranges of from 150V to 200V and from 250V to 600V respectively, the voltages being peak voltages.