An Experimental Study on Effects of Monopolar Diathermy on the Bile Ducts

Objective: To study the effects of monopolar diathermy on the bile ducts in pigs. Design: Experimental study. Setting: University hospital, Norway. Material: 18 pigs. Interventions: Laparotomy, application of diathermy at standard sites along the cystic duct, the bile ducts, and a cystic duct containing a metal clip, 3 to 12 times of 5 seconds' duration at each site. Temperature was subsequently recorded at standard measurement points on the bile ducts. Twelve pigs were killed after three weeks for assessment of the bile ducts at necropsy. Main outcome measurements: Increase in temperature in the bile duct walls and late changes in the bile ducts. Results: Temperature increased by 4-6°C during 6 of 330 diathermy applications along the cystic duct, by 4-18°C in 8 of 126 applications along the common bile duct, and by 4-11°C at the clip in 9 of 54 applications. There were no macroscopic or microscopic changes in the bile ducts. Conclusion: Monopolar diathermy induced unexpected distant increases in the temperature of the bile duct walls and at a clip on the cystic duct probably because diathermy current energy was distributed along channels of high current conductivity.