Spectral analysis interpretation of electro-surgical generator nerve and muscle stimulation

The frequency spectra of two commercial electrosurgical generators were examined during stimulated tissue cutting and compared to radio-frequency animal nerve and muscle stimulation curves generated from high-frequency sinusoidal current. During electrosurgical cutting, significant energy can exist at the fundamental frequency, as well as at frequencies lower and greater than the fundamental, which may be stimulatory to both nerve and muscle tissue. Different types of biological loads did not seem to significantly affect the spectra of each individual electrosurgical unit (ESU). However, the interaction of a specific ESU output with the biological load when compared to a pure resistive load accounts for varying impedances and resultant modulations of the fundamental frequency. Reducing electrosurgical side effects and hazards may depend, in part, on a better understanding of these underlying mechanisms.