QS135 - Impact of Inferior Mesenteric Artery Ligation Level on Anastomotic Leakage in Low Anterior Resection: A Multicenter RCT

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Purpose/Background: The optimal level of inferior mesenteric artery (IMA) ligation during laparoscopic low anterior resection (LAR) for rectal cancer is controversial. High ligation may facilitate oncological clearance but could compromise blood flow to the anastomosis, potentially increasing leakage risk. Low ligation preserves the left colic artery, which may reduce anastomotic complications. This study aimed to compare the incidence of anastomotic leakage between low and high IMA ligation in rectal cancer patients undergoing laparoscopic LAR.

Methods/Interventions: From June 2019 to August 2024, a total of 297 patients with histologically confirmed rectal adenocarcinoma were enrolled in this randomized multicenter trial across 11 institutions. Patients were randomly assigned to either the low ligation group (LL group, n = 144) or the high ligation group (HL group, n = 153), stratified by institution, preoperative chemoradiotherapy, and gender. The primary outcome was the incidence of symptomatic anastomotic leakage. Secondary outcomes included operative time, intraoperative blood loss, need for splenic flexure mobilization, stoma formation, and anastomosis height.

Results/Outcomes: Baseline characteristics were comparable between the two groups. The incidence of anastomotic leakage was not significantly different between the LL and HL Leakage rates were 4.1% in the LL group (6/143) and 5.2% in the HL group (8/155). The difference was not statistically significant (relative risk, 0.80; 95% confidence interval 0.28–2.24; p = 0.8). There were no significant differences in operative time (mean 164 ± 30 minutes vs. 159 ± 28 minutes, p = 0.4), intraoperative blood loss (mean 58 ± 20 mL vs. 55 ± 18 mL, p = 0.8), stoma formation rates (18.8% vs. 18.3%, p = 1.0), or anastomosis height (mean 5.8 ± 1.2 cm in both groups, p = 0.8). However, the need for splenic flexure mobilization was significantly higher in the LL group (p = 0.002), with extensive mobilization required in 56.3% (81/144) of LL patients compared to 34.6% (53/153) of HL patients.

Conclusion/Discussion: Low ligation of the IMA did not significantly reduce the incidence of anastomotic leakage compared to high ligation in patients undergoing minimal invasive LAR for rectal cancer.