fig1

Figure 1. Photographs showing the procedure of an intersphincteric resection combined with transanal rectal dissection. A: Tumor was found at 4 cm from the anal verge, on the posterior side of the rectum; B-D: division of the rectum on the posterior side was performed, taking care to preserve the internal anal sphincter as much as possible. The rectum was circularly incised, closing the cut end with an interrupted suture, and the rectum (including the tumor) was mobilized proximally, exposing the levator ani muscle; E: the rectum, including the mesorectum, was divided and mobilized up to the peritoneal reflection on the anterior side and to the rectosacral ligament on the posterior side; F: a Lap Disc Mini (Hakko Co., Ltd, Chikuma-shi, Japan) was adapted to the anal canal to maintain pressure during laparoscopy; G-H: the rectum, including the entire mesorectum, was completely removed from the pelvic floor. To avoid nerve injury in this patient, Denonvilliers’ fascia was not dissected; I: the colon and rectum were extruded through the umbilical wound and resected; J: a coloanal anastomosis was hand-sutured transanally