'4-Check' protocol for intraoperative anastomotic assessment during transanal total mesorectal excision: retrospective cohort study

Background: Anastomotic leakage is a major complication following rectal cancer surgery. The primary aim of this study was to investigate the efficacy of a protocol based on a quadruple intraoperative anastomotic assessment (4-Check) during transanal total mesorectal excision (TaTME). Methods: Patients who underwent TaTME for rectal cancer with primary anastomosis were reviewed and divided into two groups: before (pre-4-Check: April 2015 - April 2019) and after the implementation of the 4-Check protocol (May 2019 - May 2022). This protocol consisted of a multimodal anastomotic integrity assessment, including indocyanine green-evaluation of colonic stump and intraluminal anastomosis perfusion, a reverse air leak test and anastomotic doughnuts assessment. The primary outcome was incidence of clinical and/or radiological anastomotic leakage. The secondary outcome included intraoperative anastomosis defects and repairs and 30-day complication rate. Propensity score matching and multivariable analyses were performed. Results: Of 186 patients, 160 were selected: 86 patients in the pre-4-Check and 74 in the 4-Check group. After propensity score matching, there was no difference in postoperative anastomotic leakage (pre-4-Check versus 4-Check: 11.1 per cent versus 7.4 per cent; P = 0.50). However, in the 4-Check group, the intraoperative detection of defects and repairs was significantly increased (P = 0.03), and the number of complications was reduced (pre-4-Check versus 4-Check: 33.3 per cent versus 9.3 per cent, P = 0.004). Multivariable analyses confirmed that the use of the 4-Check protocol, the detection of anastomotic defects and increased albumin levels were associated with a reduced number of complications. Conclusion: The 4-Check protocol allowed the intraoperative detection and repair of anastomotic defects. Anastomotic leakage rates were not reduced; however, 30-day complication rates were lower after implementation of this protocol.