Transanal endoscopic resection with peritoneal entry: a word of caution

Background: Peritoneal entry during transanal endoscopic microsurgery (TEM) can usually be managed transanally with full-thickness suture closure by experienced operators. The preliminary safety of transanal minimally invasive surgery (TAMIS) has been demonstrated, but the reported experience with upper rectal tumors is limited. The incidence and management of peritoneal entry during transanal endoscopic surgery across various platforms have not been previously evaluated.

Methods: Retrospective analysis of a prospectively maintained database of all transanal endoscopic resections performed at a single institution between January 2008 and December 2014 was conducted. Cases with and without peritoneal entry were evaluated with respect to transanal platform used, surgical indication, size, location and distance from the anal verge, and incidence of postoperative complications.

Results: A total of 78 transanal endoscopic procedures were performed on 76 patients using the rigid transanal endoscopic operation (TEO, 65.4 %), TEM (26.9 %), and TAMIS platform (7.7 %). The most common surgical indication included endoscopically unresectable adenomas (50 %). The average distance of lesions from the anal verge (AV) was 9.6 cm (range 4-20 cm). Peritoneal entry occurred in 22 cases (28.2 %). Platform used (TAMIS vs. rigid, p < 0.05), mean distance from the AV (p < 0.0001), location along the rectum (p = 0.01), and mean specimen size (p = 0.01) were associated with a higher likelihood of peritoneal entry. All rectal defects associated with peritoneal entry were successfully closed transanally except for two (TEM and TEO) cases that required conversion to laparoscopic low anterior resection and laparoscopic Hartmann's, respectively. There were four TAMIS cases that required conversion to TEO platforms.

Conclusion: In this high-risk TEM, TEO, and TAMIS series (one-third of rectal lesions located in the upper rectum), 91 % of all peritoneal entries were managed transanally without increased morbidity. TAMIS for upper rectal lesions was associated with a high risk of complicated peritoneal entry requiring conversion to a rigid platform.