A tissue ablation system that includes a cannula (101, 201) that includes an elongated shaft (101) having a proximal end and a distal end, an axis (120) at the proximal end of the cannula, in which the tree of cannula (101) includes a light (112) that is open at the proximal end, and the outer surface of the proximal end of cannula shaft includes electrical insulation (107)； and an electrode (140) that includes an elongated shaft (144) with a proximal end and a distal end, a shaft (145) at the proximal end of the electrode, a connection (158) to an electrosurgical generator (604), and a connection (151, 154) to a refrigerant supply (624), in which the electrode shaft includes a light (720) within which the refrigerant from the refrigerant supply (624) circulates； wherein when the electrode shaft (144) is inserted into the cannula light (112) by means of the opening (122) at the proximal end of the cannula, and the electrode shaft (145) is coupled with the axis of cannula (120), then the outer surface of the electrode assembly (140) and the cannula includes at least one electrically conductive active tip (111, 164), an electrosurgical generator output signal (604) connected to the electrode (140) is leads to the active tip (111, 164), and the refrigerant flowing from a supply of refrigerant (624) in the electrode shaft (144) cools the active tip (111, 164)； wherein the cannula light (112) includes an opening (114) at the distal end of the cannula shaft (101), wherein the distal end of the electrode shaft is adapted to extend beyond or substantially align with, the opening (114) when the electrode shaft (144) is inserted into the cannula light； characterized in that the outer surface of the distal end of the cannula shaft (111) is not insulated and forms at least a part of the active tip (111, 164).Un sistema para ablación de tejido que incluye una cánula (101, 201) que incluye un árbol alargado (101) que tiene un extremo proximal y un extremo distal, un eje (120) en
