How to perform an anastomosis following a low anterior resection by taTME surgery: From top to bottom techniques.

To describe the range of possibilities and our group´s clinical outcomes when performing different types of anastomosis during transanal total mesorectal excision (taTME).A retrospective analysis was performed based on four taTME series from 2016 to 2021. Inclusion criteria were patients with rectal cancer in whom a sphincter-saving low anterior resection by taTME was performed. Four different techniques were employed for the anastomosis construction; A) abdominal view, B) transanal view, C) hand-sewn coloanal anastomosis and D) pull-through. Intra and postoperative data was collected and compared.A total of 161 patients were included. Tumour height was lower in groups C and D (4 (3-5) vs. 7 (6-8) group A vs. 6 (5-7) group B, p=0.000), requiring a hand-sewn anastomosis. A transanal extraction of the specimen was more commonly performed in groups C and D (over 60% vs. 30% in groups A and B, p=0.000). The rate of temporary stoma was similar between groups A, B and C (ranging from 84 to 98%), but was significantly lower in group D (p=0.000). The overall rate of complications was similar between groups; however, group D had longer LOS (15 days vs. 5-6 in groups A, B and C, p=0.026).Every type of anastomosis construction after a taTME procedure seems to be safe and feasible and should be chosen based on surgeon´s experience, tumour height and the length of the rectal cuff after the rectal transection. Colorectal surgeons should be familiar with these techniques in order to choose the one that benefits each patient the most.