Investigations and Studies on Electrosurgery

摘要

In electrosurgical procedures, high current density radiofrequency energy (0.5 to 2.5 MHz) is used to cut tissue and simultaneously coagulate small blood vessels. Electrosurgical techniques have been in widespread clinical use since the early 1930's. The standard (i.e., monopolar) surgical technique employs a small-area 'active' electrode which the surgeon applies to cut and/or coagulate the tissue. The return path for the current is via a large-area dispersive electrode located at some convenient site on the patient, usually under the buttocks or on a limb. A 'bipolar' method is also used wherein both current source and sink are located at the cutting site. A bipolar method is most useful for coagulating vessels. The monopolar method is best for incisions, but is also useful for vascular coagulation, and is thus most frequently used in surgical procedures. The study undertaken comprises a theoretical and experimental treatment of electrosurgical dispersive electrodes, of the cutting and coagulating process at different frequencies, and of threshold temperatures for tissue damage. The results: (1) provide a rationale basis for evaluating new dispersive electrode designs; (2) identify the significant design variables affecting thermal performance; (3) describe the performance of representative existing commercial dispersive electrode designs; and (4) identify safe temperature limits for electrodes in contact with skin.