US Patent 7828797 Electrosurgical accessing of tissue with controlled collateral thermal phenomena

Method, system and apparatus for carrying out electrosurgical procedures interstitially. Elevated temperature fluid such as steam generated by an instrument born electrosurgical cutting arc is evacuated through an intake port located adjacent the cutting electrode. Instrument cannula surface heating caused by transport of the heated fluid is isolated. Such thermal isolation is provided by a thermal shield which may be configured as an enveloping sheath.