The Effect of Ischemia of the Incision Margins on Colonic Anastomosis Leak: A Rat Model

Background: Anastomotic leakage remains a serious complication following colorectal surgery, often associated with significant morbidity and mortality. Impaired blood supply at the incision site has been suggested as a key contributing factor. Objective: To develop and validate a reproducible rat model of colonic anastomotic leakage induced by graded mesocolon ischemia at the incision margins. Methods: 144 rats underwent end-to-end colonic anastomosis with five different levels of mesocolon ligation, ranging from no ligation (control) to 2 cm ischemia on each side. Postoperative outcomes, including anastomotic integrity, abscess formation, and mortality, were assessed 10 days postoperatively. Results: Anastomotic leak rates increased proportionally with the extent of mesocolic ischemia: 0% in controls, 19.04% with 0.2 cm ligation, 44.23% with 0.4 cm, and 100% with 1 and 2 cm. The model was consistent and reproducible. Conclusions: This model reliably induces graded anastomotic leaks in rats and may serve as a platform for future studies evaluating interventions to reduce leak risk in high-risk colorectal surgery patients.