Electrosurgical generator method
AssigneeGyrus Medical Limited
InventorsNigel Mark Goble, Colin Charles Owen Goble
Life of this patent
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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.
Claims17
A method of operating an electrosurgical system which has a generator with an output coupled to an electrode assembly having an electrode for operation in a conductive liquid, wherein the method comprises:
- applying radio frequency power to the electrode, and
- automatically adjusting the radio frequency power applied to the electrode to maintain the conductive liquid adjacent the electrode at its boiling point for tissue desiccation, so that vapour bubbles form on the electrode's surface without forming a vapor pocket surrounding the electrode.
A method of operating an electrosurgical system which has a generator with an output coupled to an electrode assembly having an electrode for operation in a conductive liquid, wherein the method comprises:
- applying radio frequency power to the electrode,
- monitoring an electrical signal related to the voltage developed at the output of the generator, and
- reducing the applied power when said signal reaches a predetermined threshold value associated with an increased load impedance,
- whereby only sufficient radio frequency power is applied to the electrode to maintain the conductive liquid adjacent the electrode at its boiling point for tissue desiccation, so that vapour bubbles are formed on the electrode's surface without forming a vapour pocket surrounding the electrode.
An electrosurgical tissue desiccation method comprising:
- providing an electrosurgical system comprising an electrosurgical radio frequency generator coupled to an electrode assembly having a treatment electrode;
- introducing the electrode assembly into a selected operation site with the treatment electrode contacting the tissue to be treated and with the tissue and the treatment electrode immersed in a conductive liquid;
- actuating the generator to apply radio frequency power to the treatment electrode;
- and
- automatically adjusting the radio frequency power during its application to the treatment electrode by the generator to maintain the conductive liquid adjacent the treatment electrode at its boiling point, so that vapour bubbles are formed on the electrode' surface without creating a vapour pocket surrounding the electrode.
An electrosurgical tissue desiccation method comprising:
- providing an electrosurgical system comprising an electrosurgical radio frequency generator coupled to an electrode assembly having an active electrode and a return electrode,
- introducing the electrode assembly into a selected operation site with the tissue and said electrodes immersed in a conductive liquid;
- actuating the generator to apply electrosurgical power to the active electrode and thereby to locally apply heat to the tissue;
- and
- while the generator is actuated, automatically adjusting the radio frequency power applied to the active electrode by the generator to maintain the conductive liquid adjacent the active electrode at its boiling point so that vapour bubbles are formed on the electrode's surface without forming a vapour pocket surrounding the active electrode.
Dependencies are inferred from the claim text.