Laparoscopic Cholecystectomy And Capacitive Coupling - Coag Versus Blend Mode Causing Thermal Injury at Port Site Skin

Overview

Monopolar radiofrequency energy is used to perform the laparoscopic cholecystectomy operation. The appearance of burns are common following laparoscopic cholecystectomy; particularly at the port site of the active electrode. Willson et al found that 9 out of 19 skin biopsies from the skin adjacent to the port site of the monopolar instrument's active electrode were found to have thermal injury by histology. \[Willson et al. Surg Endosc (1997) 11:653\] Authors have speculated that using different generator modes may lead to less capacitive coupling; \[Wu et al Am J Surg (2000) 179: 67\] although no data exists to support these speculations. The investigators hypothesize that capacitive coupling electrosurgical injuries from monopolar instruments are occurring during laparoscopic cholecystectomy operations. The investigators hypothesize that use of blend modes will reduce the incidence of capacitive coupling thermal injuries during laparoscopic operations in comparison to coag modes.

SPECIFIC AIM: Compare incidence of skin burns caused by using coag versus blend monopolar instrument modes at the active electrode port site (epigastric port), and at the non-active electrode port sites (umbilical and right abdominal wall). OUTCOME MEASURE: Histologic evidence of thermal injury at the skin biopsy sites of the active electrode port, the camera port and the medial assistant port. Histology will be performed by a blinded pathologist. POPULATION TO BE ENROLLED: Subjects undergoing elective laparoscopic cholecystectomy will be recruited in the principle investigators pre-operative clinic. All subjects will be 18 years and older. STUDY DESIGN AND METHODS: Written informed consent will be obtained in all subjects prior to enrollment. Subjects will be randomized on the day of surgery to undergo the laparoscopic cholecystectomy operation with either the coag or blend modes of using standard monopolar electrosurgery instruments. The randomization process will occur by using a random number generator. A total of 40 subjects will be recruited; 20 subjects per group. Shave skin biopsies will be performed at the edge of the incisions of the active electrode port, the camera port and the medial assistant port on the right abdominal wall. The incisions and skin will be otherwise opened and closed in the routine clinical manor. STATISTICAL ANALYSIS The incidence of skin burns created using coag or blend modes will be compared individually at all three port sites using chi-squared or Fisher's exact test where appropriate. Baseline demographic data (e.g., gender, age, body mass index, operation time, blood loss, indication for operation and histology) will be compared in the two groups.