Tissue Penetration of Bipolar Electrosurgery at Different Power Settings

Introduction: Bipolar electro-surgery is used in all disciplines of surgery to aid in haemostasis. Although common sense dictates tissue penetration will be effected by power settings, no formal evaluation of this effect has been made. We performed an experiment to accurately measure the tissue penetration of bipolar diathermy at different strengths.

Materials and Methods: Laboratory study using a porcine liver model. Different wattages (10–40 W) of bipolar electro-surgery were applied to deceased porcine liver, with and without fascial covering for a fixed duration. The tissue penetration was measured with a light microscope in two planes, horizontal and perpendicular. The data was compared with a Spearman Rank correlation coefficient calculation.

Results: For both fascia and non fascia covered liver there was a statistically significant correlation between increasing power and superficial spread of tissue penetration (Non fascia rho=0.3604, p =0.05) (Fascia rho=0.893, p =0.0068). No such correlation was noted between burn depth and wattage (Non fascia rho=-0.75, p =0.93) (Fascia rho = 0.714, p = 0.0713). There was a statistically significant correlation between the diameter and depth of tissue penetration for fascia covered tissue (rho 0.893, p = 0.0068) but not for non fascia covered tissue (rho 0.3604, p =0.42).

Discussion: There is a clear relationship between the power setting of electro surgery and superficial spread of tissue damage however the effects of power setting and deep tissue penetration are not so clear. Interestingly, maximum tissue effects were not encountered at the higher power settings but between 20 and 30 W.