Thermal characterization of electrosurgery.

The volumetric heating response of soft tissues to electrosurgical cutting and coagulation was studied. A series of experiments was conducted with thermistor probes embedded in a surrogate medium during controlled application of the electrosurgery current. A series of temperature profiles was obtained for various thermistor probe locations. These temperature profiles were found to be linear, exponential, or double exponential, depending upon the probe-incision distance. Temperatures next to the site of tissue destruction approached 70 degrees C, within 2 seconds of application of power. Temperature changes due to lateral heating were an order of magnitude greater than temperature changes directly under the incision. Anisotropic heat conduction was observed for muscle fibers oriented in different directions.