AN ELECTROSURGICAL SYSTEM

摘要

An electrosurgical system has an electrosurgical generator and a bipolar electrosurgical instrument, the generator being arranged to perform a treatment cycle in which radio frequency energy is delivered to the instrument as an amplitude-modulated radio frequency power signal in the form of a succession of pulses characterised by periods of at least 100 milliseconds between successive pulses and by a predetermined pulse mark-to-space ratio. Energy delivery between pulses is substantially zero and the mark-to-space ratio is typically 1:4 or less. Each burst is of sufficiently high power to form vapour bubbles within tissue being treated and the time between successive pulses is sufficiently long to permit condensation of the vapour. The treatment cycles may each include an initial period and a subsequent period, the pulse duty cycle being increased or energy delivered continuously in the subsequent period in order that tissue coagulation can be achieved quickly despite increasing tissue impedance.