Effect of inferior mesenteric and left colic artery sheath resection on long-term left colic artery patency: a randomized controlled pilot trial

Objective To evaluate whether resection of the inferior mesenteric artery (IMA) and left colic artery (LCA) perivascular sheath, while preserving the LCA, affects postoperative LCA patency and perioperative outcomes in minimally invasive radical rectal cancer surgery. Methods In this single-center randomized controlled pilot trial (registration number: ChiCTR2200063479), 60 patients were assigned 1:1 to sheath resection (experimental group, n = 30) or sheath preservation (control group, n = 30). The prespecified primary endpoint was LCA patency at 6 months; 12- and 24-month patency assessments were exploratory. Continuous and categorical outcomes were compared using Welch’s t test, the Mann-Whitney U test, the Pearson chi-square test, or an exact test, as appropriate. Follow-up imaging was analyzed on an available-case basis. Results The experimental group had a higher lymph-node yield (17.17 ± 5.07 vs. 13.13 ± 4.76; mean difference, 4.03; 95% CI, 1.49–6.57; P = 0.002) and fewer patients with < 12 retrieved nodes (4/30 [13.3%] vs. 12/30 [40.0%]; P = 0.020). Time to first flatus was longer after sheath resection (median, 3.0 vs. 2.0 days; P = 0.001), whereas operative time, blood loss, analgesic duration, bowel frequency, and complications did not differ significantly. Two patients (one per group) were lost to follow-up. At 6 months, LCA occlusion occurred in 5/29 patients (17.2%) in the experimental group and 6/29 (20.7%) in the control group (risk difference, -3.4% points; 95% CI, -23.6 to 17.0; P = 0.738). The corresponding proportions in the experimental and control groups were 8/29 (27.6%) and 10/29 (34.5%) at 12 months ( P = 0.570), and 11/29 (37.9%) and 16/29 (55.2%) at 24 months ( P = 0.188). Conclusion In this pilot trial, perivascular sheath resection was not associated with a statistically significant increase in LCA occlusion through 24 months and was associated with a higher lymph-node yield. However, the patency estimates were imprecise; the nonsignificant differences should not be interpreted as proof of equivalence or non-inferiority. The longer time to first flatus also warrants consideration. Trial registration Chinese Clinical Trial Registry (ChiCTR2200063479), registered on 8 September 2022. Retrospectively registered.