Exit spark control for an electrosurgical generator

Abstract

An electrosurgical generator is disclosed that includes an exit spark control system. Exit sparking occurs when energy arcs to the patient as the active electrode is withdrawn from the patient. A basis for controlling the exit spark is to automatically change the frequency at which the final amplifier is driven whenever the conditions for an exit spark are detected. The change in frequency acts to lower the gain and efficiency in the final amplifier and dissipate energy as heat. The exit spark control system includes a frequency adjustable waveform generator and a logic capability for determining the conditions when exit sparking is likely to occur. Sensors and an algorithm in a microcontroller are preferably required to detect the conditions preceding exit sparking occurrence. It is further preferred that, the algorithm also control the sequencing of events: first stopping the electrosurgical output to prevent an arc from initiating and then changing the driving frequency appropriately to dissipate excess stored energy. The output waveform may be stopped for only a short time or the surgeon will detect drag while cutting through tissue.