Efficacy of Filter Trocar for Clear Visualization during Laparoscopic Cholecystectomy: A Prospective Randomized Controlled Trial.

Filter trocar designed to eliminate harmful smoke is also regarded as effective for improving surgical visualization. The aim of this study is to evaluate the efficacy of filter trocar in maintaining clear operative view. From 2019 to 2020, 100 patients underwent laparoscopic cholecystectomy and they were randomized to either the control or filter group. The primary end point was a laparoscopic operative view score (1, clear; 2, slightly blurry; 3, completely blurry) during gallbladder dissection from the liver bed when dissection was started (LV1), when dissection was half completed (LV2) and when dissection was completed (LV3). Between the control and filter groups, there were no significant differences in mean LV1 (1.44 vs. 1.40, p = 0.234) and LV3 (1.86 vs. 2.01, p = 0.880). There was no significant difference in the mean duration of suction after dissection (3.82 s vs. 3.67 s, p = 0.097) and the mean number of laparoscope removals from inside to outside the body to clean during gallbladder dissection from the liver bed (0.55 vs. 0.22, p = 0.963) or the mean amount of time required to dissect the gallbladder from the liver bed (221.58 s vs. 177.09 s, p = 0.253). The study demonstrated that filter trocar is not as effective as expected in the maintenance of clear operative view. Further study is needed to develop devices to improve clear surgical visualization.