Anastomotic leakage (AL) is a lethal complication after colorectal resection, affecting morbidity, mortality, and oncological outcomes in colorectal cancer patients. Measuring the preoperative pressures exerted by the sphincter muscle complex or pelvic floor muscles can provide valuable information regarding the risk of anastomotic disruption, as high anastomotic tension is a critical factor in its development. To provide objective criteria, this study aims to evaluate the preoperative values that characterize the patients with high risk of AL using a high-resolution anorectal manometry (HRAM).

This is a retrospective cohort study. This study was conducted in an academic setting at a single institute. Among 221 rectal cancer patients who underwent sphincter-saving surgery between 2019 and 2021, 137 patients who initially underwent anorectal functional test with a high-resolution anorectal manometry (HRAM) were included. Preoperative HRAM was performed to measure resting and squeezing pressure, length of high-pressure zone, intrarectal pressure, rectoanal pressure difference, and maximum rectal compliance. The primary outcome was the occurrence of anastomotic leakage post-surgery, as defined by the International Study Group of Rectal Cancer. The relationship between manometric factors and AL was analyzed using univariate and multivariate analysis.

The study found that a longer length of the high-pressure zone in HRAM was an independent risk factor for AL, with an odds ratio of 2.77 (95% CI: 1.261 – 6.091, p-value = 0.011). When patients with anastomotic leakage were compared to the ones without, the patients who experienced leakage tended to be younger, and male patients experienced anastomotic leakage at a higher rate, although statistical significance was not observed. All patients with anastomotic leakage had diverting stoma formation. although without statistical significance. Mean resting pressure and maximal squeezing pressure in age ≤ 70 were higher compared to the age >70. Maximal squeezing and intrarectal pressure were significantly higher in male patients than in female patients. Patients with anastomotic leakage showed significantly longer lengths of high-pressure zone during resting state than those without leakage. On multivariate analysis, the length of the high-pressure zone appeared as an independent risk factor related to anastomotic leakage with an odd ratio of 2.77 with a confidence interval of 1.261 – 6.091, p-value = 0.011.  On the ROC curve, the length of the high-pressure zone from 2.35cm to 2.55cm showed that the area under the ROC curve (AUC) is 0.58.

These manometric findings suggest that the functional pressure in the distal anastomotic limb affects anastomotic stability, with higher pressure in the distal limb posing a greater risk of developing anastomotic leakage.

This study proposes that the longer length of the high-pressure zone in HRAM could serve as a predictive indicator for postoperative anastomotic leakage. This finding could be particularly valuable in determining whether to create a protective diverting stoma, especially in male patients.

Continence 12S (2024) 101625
DOI: 10.1016/j.cont.2024.101625