Surgical technique for mesorectal division during robot-assisted laparoscopic tumor-specific mesorectal excision (TSME) for rectal cancer using da Vinci Si surgical system: the simple switching technique (SST).

In a narrow pelvic cavity, performing sufficient tumor-specific mesorectal excision (TSME) is difficult. Even in robot-assisted laparoscopic surgery (RALS), mesorectal division is difficult in a narrow pelvic cavity. To overcome this difficulty, we invented a novel method of mesorectal division. In this new approach, we switched the fenestrated bipolar forceps and the double-fenestrated forceps with each other so that both instruments were placed on the same (right) side of the patient. After the mesorectal fat and vessels were coagulated using the fenestrated bipolar forceps, coagulated tissues were divided using the monopolar scissors in the same direction. We named this technique the "simple switching technique (SST)". We retrospectively collected data and evaluated the usefulness of SST in 24 consecutive patients who underwent RALS TSME between July 2018 and January 2020. Twelve patients underwent SST, and 12 patients underwent other conventional surgical methods (non-SST). The median operation time for mesorectal division was 809.5 s (range 395-1491 s) in the SST group and 985.5 s (range 493-2353 s) in the non-SST group. The coefficient of variation for non-SST was 0.545, which was > 1.5 times the coefficient of 0.360 for SST. Although no significant differences were found for operation time for mesorectal division, the operation time for mesorectal division by SST tended to be shorter than by non-SST (P = 0.157). No significant differences were found regarding short-term outcomes between the groups. SST is feasible and can be an optional method of mesorectal division in RALS TSME.