Exploratory assessment of the clinical significance of the collateral system between the superior mesenteric artery and inferior mesenteric artery in laparoscopic rectal cancer surgery

Abstract

Abstract Background Rectal cancer (RC) is a common and lethal malignant tumor, and surgical treatment is essential. The collateral system between the superior mesenteric artery (SMA) and inferior mesenteric artery (IMA) remains controversial, and its potential clinical significance in RC has not been fully clarified. This study aimed to preliminarily explore and classify this collateral system and its clinical roles in laparoscopic RC surgery. Methods This single-center retrospective study enrolled patients who underwent laparoscopic radical resection for RC at Fuyang City People’s Hospital from January 2022 to March 2026. Based on arterial-phase contrast-enhanced computed tomography (CT) images, three-dimensional (3D) reconstructions of the SMA, IMA, and splenic flexure inter-mesenteric anastomosis (SF-ImA) were performed using 3D Slicer. Univariate and multivariate logistic regression analyses were conducted to evaluate risk factors for anastomotic leakage (AL). Subgroup analysis was further performed to evaluate the potential clinical value of SF-ImA in laparoscopic RC surgery. Results SF-ImA was detected in 60.10% of RC patients, including 13.94% with central mesocolic anastomosis and 46.15% with intermediate mesocolic anastomosis. The tumor location (low vs. high, OR: 13.377; 95% CI: 2.262–259.500, P = 0.018), N stage (OR: 1.339; 95% CI: 1.095–14.183, P = 0.038), and surgical duration (OR: 1.026; 95% CI: 1.013–1.042, P = 0.001) were independent risk factors for AL. Preserving left colic artery (LCA) (OR: 0.206; 95% CI: 0.062–0.611, P = 0.006) was an independent protective factor. Subgroup analysis confirmed that LCA preservation exerted a protective effect against AL exclusively in patients without SF-ImA (OR: 0.041, 95% CI: 0.002–0.357, P = 0.012). For patients with SF-ImA, LCA preservation may fail to confer a protective effect against AL and was associated with longer operative duration ( P < 0.05). Conclusion SF-ImA can be effectively evaluated and classified via contrast-enhanced CT combined with 3D reconstruction. Preoperative assessment of SF-ImA may assist individualized surgical planning for RC patients.