Patient-related risk factors for outlet obstruction in diverting loop ileostomy following minimally invasive rectal cancer surgery

INTRODUCTION: Anastomotic leakage (AL) is a serious complication after rectal cancer resection, often mitigated by diverting loop ileostomy. However, outlet obstruction remains a significant concern, potentially prolonging hospitalization and requiring reintervention. While surgical risk factors have been explored, patient-specific anatomical factors are less well understood. This study aimed to identify patient-related risk factors for outlet obstruction and evaluate a preventive surgical modification in high-risk patients undergoing laparoscopic and robotic rectal cancer surgeries. METHODS: This retrospective study included 318 patients who underwent laparoscopic or robotic rectal resection with a diverting loop ileostomy. Risk factors were assessed in a control cohort (April 2015-February 2020), followed by a modified ileostomy technique in a validation cohort (March 2020-December 2024). RESULTS: Increased rectus abdominis muscle thickness (TAM) and larger visceral fat area (AVF) were independent risk factors for outlet obstruction (p = 0.037 and p = 0.041, respectively). Patients with both factors had the highest incidence (52.6%). The modified technique significantly reduced obstruction among high-risk patients (p = 0.003) without increasing parastomal hernia rates. CONCLUSIONS: TAM and AVF are independent predictors of outlet obstruction. A tailored fascial modification reduced obstruction in high-risk patients, supporting the value of preoperative anatomical assessment in surgical planning.