Anastomotic leakage and stoma formation in left-sided colorectal surgery: Risk stratification and surgical decision-making - a review of current evidence

The surgical approach following left-sided resection of the colon and rectum remains a significant intraoperative challenge in colorectal surgery. One of the most severe complications of restoring gastrointestinal continuity is anastomotic leakage (AL). This narrative review summarizes current data on risk factors for AL and criteria supporting the choice between primary anastomosis, primary anastomosis with a diverting stoma, and Hartmann’s procedure. The literature search was conducted in the PubMed database (August - September 2026) and supplemented with current guidelines from the WSES, ACPGBI, ASCRS, and EAES/SAGES. Analysis of the available data indicates that the significance of individual risk factors depends on the patient population and the type of resection performed, and that no individual factor should determine the choice of surgical strategy. The strongest evidence supporting diverting stoma formation concerns low anterior resection for rectal cancer. In perforated diverticulitis and malignant obstruction, primary anastomosis appears to be a safe option in stable, appropriately selected patients, while Hartmann's procedure is preferred for critically ill patients or those with significant comorbidities. Current guidelines from surgical societies provide valuable guidance, although their recommendations are not fully consistent. The choice of operative strategy should therefore be supported by an individualised, multifactorial risk assessment that considers both the likelihood of AL and the anticipated consequences of each surgical approach.