[Last critical step for transanal total mesorectal excision: anastomosis]

Colorectal anastomosis remains a key aspect in mid- and lower-rectal surgery, particularly in patients who are male, obese, status post neoadjuvant chemoradiation, or possess narrow pelvic anatomy. Transanal total mesorectal excision (taTME) and transabdominal total mesorectal excision (TME) both primarily allow position of the tumor to dictate whether circular stapling or hand-sewing is utilized to achieve anastomosis. Given that taTME only requires a single circular stapler to achieve anastomosis, it consequently decreases the risk of jeopardizing blood supply to the anastomotic site. Should transanal hand-sewing be pursued, numerous points in performing the purse-string suture warrant particular attention: (1) Before suturing, separate the distal rectum to be anastomosed from the surrounding tissues, and ensure the full-layer suture of the distal purse-stitched suture. (2) It is recommended that beginners complete the suturing process under direct visualization without removing the transanal platform. (3) Commonly used anastomosis designs include end-to-end, side-to-end, J-pouch, or coloplasty, depending on patient characteristics and surgeon preferences. Our single-institution clinical experience suggests that taTME patients who underwent neoadjuvant chemoradiation or transanal hand-sewn anastomosis should still have a temporary colostomy created. To date, literature has yet to demonstrate the superiority of taTME anastomosis outcomes. This publication aims to point out anastomosis techniques and safety pointers, as well as clinical experiences.