Objective: The purpose of this study was to assess the extent and rate of vaginal tissue injury associated with the utilization of various monopolar electrosurgical power settings when laparoscopically transecting vaginal tissue.
Methods: This is an Institutional Animal Care and Use Committee-approved prospective, paired, single-blinded study. Externalized porcine vagina was transected using monopolar energy at 30, 50, and 80 W in the cut mode with laparoscopic Endo Shears. The slides were prepared and stained with both hematoxylin-eosin and Masson trichrome and were examined by board-certified veterinary pathologists blinded to the study.
Results: There were 18 swine; each animal was tested on all 3 power settings (n = 54). Tissue injury was measured to a mean (SD) of 767 (519) μm at 30 W, 690 (600) μm at 50 W, and 556 (470) μm at 80 W. When comparing the monopolar settings, the results were as follows: 30 versus 50 W (P = 0.33), 30 versus 80 W (P = 0.067), and 50 versus 80 W (P = 0.17). The mean (SD) time for complete transection was measured at each power setting (n = 18), with 35.8 (5.4) seconds for 30 W, 13.5 (5.5) seconds for 50 W, and 8.4 (5.1) seconds for 80 W (P < 0.001). There was a statistically significant difference in the mean (SD) rates of injury, with 20.8 (8.8) μm/s at 30 W, 39.8 (11.8) μm/s at 50 W, and 50.1 (19.2) μm/s at 80 W (P = 0.01).
Conclusions: Using various power settings of monopolar energy may not make a significant difference in swine vaginal tissue damage at the time of colpotomy. However, there was a significant difference in the times and rates at which tissue was transected when using higher powers. We recommend using the 50- or 80-W setting, as this will likely decrease surgical times without altering vaginal tissue damage.