ELECTROSURGICAL SYSTEM

摘要

An electrosurgical system includes an electrosurgical generator to which the active and return electrodes (18, 20) of an electrosurgical instrument (12) are connected. In use the electrodes are immersed in electrically-conductive fluid to complete a conduction path between them. The electrodes (18, 20) are located on a shaft (16) of the instrument which extends from a handle (14). The shaft is covered in a translucent flexible sheath (50) comprising a tube (60) having a large proximal opening (62) to enable insertion of the instrument within the sheath, and a narrower distal opening (64) through which the distal end of the instrument shaft projects, thereby to expose the active electrode (18) to the electrically-conductive fluid. Suction is applied to the interior of the sheath at an outlet port (66), and a seal (72) at the proximal end of the tube cooperates with a proximal surface (74) on the instrument handle to form a fluid-tight seal so that the suction is transmitted to the distal opening, in order to suck bubbles and debris away from the region around the active electrode (18). The distance between the active electrode (18) and the distal opening (64) of the tube (60) is chosen so that sufficient bubbles are sucked from the region around the active electrode to enable clear viewing of a treatment site without causing the resultant flow of conducting fluid over the active electrode to quench a vapour pocket which is formed around the active electrode when the instrument (12) is used to vaporise tissue.