Small Bowel Obstruction Caused by Meckel’s Diverticulum Entrapped behind Transperitoneal Sigmoid Colostomy: A Case Report

INTRODUCTION: Meckel's diverticulum is the most common congenital anomaly of the gastrointestinal tract, often asymptomatic but occasionally causing inflammation, bleeding, or intestinal obstruction. Permanent colostomy after abdominoperineal resection (APR) is typically created via either a transperitoneal or extraperitoneal route. Although small bowel obstruction (SBO) is a known complication of transperitoneal colostomy, SBO caused by Meckel's diverticulum entrapped behind the stoma has not previously been reported. We describe an extremely rare case of SBO caused by adhesion between Meckel's diverticulum and the sigmoid colon at the stoma site. CASE PRESENTATION: A 70-year-old man underwent robot-assisted APR with transperitoneal sigmoid colostomy for rectal cancer (pT3N0M0, UICC 9th edition). Ten months later, he presented with progressive abdominal pain and distension. CT demonstrated a caliber change without evidence of strangulation, suggesting adhesive SBO. Conservative management with nasogastric decompression and a long intestinal tube failed, and aspiration pneumonia developed during tube placement, temporarily delaying surgery. After recovery, laparoscopic exploration was performed. A 6-cm Meckel's diverticulum located approximately 1 m proximal to the ileocecal valve was found to be firmly adherent to the elevated sigmoid colon at the stoma site. The dilated small bowel loops were entrapped behind the colostomy segment, creating an obvious transition point. Laparoscopic adhesiolysis and diverticulectomy were successfully completed. The patient recovered uneventfully, resumed oral intake on POD 6, and has had no recurrence of SBO. Histopathology confirmed Meckel's diverticulum. CONCLUSIONS: This case demonstrates a rare mechanism of SBO caused by Meckel's diverticulum trapped behind a transperitoneal colostomy. From the anatomical perspective, the extraperitoneal route could reduce the risk of adhesion-related complications compared to the transperitoneal route. Laparoscopy served as an effective dual-purpose modality for both diagnosis and minimally invasive treatment when the etiology of SBO is uncertain.