Abstract

An electrosurgical generator for driving one or more separate electrosurgical implements, e.g., an electrosurgical scalpel and an electrosurgical forceps, over separate output channels. Bipolar electrodes on the scalpel blade are energized by a radio frequency (rf) power source which, by proper manipulation of push-button switches on the scalpel handle, can be made to operate selectively in a CUT and in a COAG (coagulate) mode. In the CUT mode, the rf energy is applied to the tissue, via electrodes which are closely spaced, yielding a high current density. In the COAG mode, the energy is applied to electrodes which are spaced relatively far apart so as to produce heating sufficient to cauterize, but not to the point where the tissue is rent. The generator also provides circuitry for energizing an ultrasonic transducer mechanically coupled to one of the surgical implements whereby vibratory energy is simultaneously applied to the implement along with the rf CUT/COAG energy. The drive to the transducer is amplitude modulated at a frequency which enhances resonance of the blade and handle containing the blade. A novel feedback control sense variations in load impedance and adjusts the power delivered to the electrodes so as to maintain a relatively flat power vs. load impedance characteristic.