Electrosurgical generator

A system for tissue ablation including an electrode configured for insertion into bodily tissue, the electrode including an elongated metallic tubular electrode shaft having a proximal end and a distal end, and an elongated temperature-sensor shaft having a proximal and a distal end, wherein the proximal end of the electrode shaft is electrically insulated to define the electrode active tip at the distal end of the electrode shaft;

• the electrode active tip is configured to conduct RF current to bodily tissue from an RF generator;
• the electrode shaft includes a coolant lumen at least within the active-tip portion of the electrode shaft;
• fluid coolant circulates within the coolant lumen;
• the electrode shaft includes a temperature-sensor lumen that is physically separated from the coolant lumen by a barrier within the electrode;
• the temperature-sensor shaft is positioned within the temperature-sensor lumen;
• the distal end of the temperature-sensor shaft is configured to extend out from the temperature-sensor lumen from the distal end of the electrode shaft into bodily tissue;
• the temperature sensor shaft is not connected to the temperature-sensor lumen at the distal end of the temperature-sensor lumen;
• the temperature-sensor shaft is configured to not deliver sufficient RF current from the RF generator to the bodily tissue to substantially heat the bodily tissue;
• the temperature-sensor shaft includes an elongated temperature-sensor-shaft tube, a plastic layer forming the outer surface of a plastic-layer length of the temperature-sensor-shaft tube, at least one temperature-sensor wire within the lumen of the temperature-sensor-shaft tube, and a temperature sensor attached to the at least one temperature-sensor wire and to the temperature sensor-shaft tube;
• the temperature sensor forms the outer surface of the distal point of the temperature-sensor shaft and is configured to directly contact bodily tissue;
• and the plastic-layer length spans from a first part of the temperature-sensor shaft inside the temperature-sensor lumen, to a second part of the temperature-sensor shaft that is configured to extend out from the temperature-sensor lumen into bodily tissue and that is proximal to the temperature sensor.