Small Bowel Obstruction Due to Concurrent Petersen's and Pouch of Douglas Hernias in a Patient With a Complex Surgical History: A Rare Surgical Case.

Internal hernias are a rare but significant cause of small bowel obstruction, particularly in patients with a history of abdominal surgery such as Roux-en-Y gastric bypass (RYGB). Although Petersen's hernia is the most commonly encountered internal hernia in these patients, herniation into the Pouch of Douglas is an exceedingly rare occurrence. This report describes the case of a 77-year-old female with a complex surgical history, including RYGB and hysterectomy, who presented with several months of postprandial abdominal pain, nausea, and vomiting. A computed tomography (CT) scan initially suggested mild bowel distention without clear evidence of obstruction. However, due to the inability to tolerate oral intake, a follow-up CT scan was performed and revealed dilated loops of the small bowel, prompting surgical intervention. Intraoperatively, two internal hernias were identified: one at Petersen's defect and another in the Pouch of Douglas, the latter being the cause of the obstruction. Both hernias were reduced, and the peritoneal defect in the Pouch of Douglas was closed using sutures. The patient recovered without complications and was discharged to rehabilitation. This case demonstrates the importance of considering internal hernias, including rare types, in post-surgical patients presenting with nonspecific symptoms of bowel obstruction. Early diagnosis and timely surgical management are crucial to prevent complications such as bowel ischemia and to ensure optimal outcomes. Closing peritoneal defects during hernia repairs is essential to minimize the risk of recurrence. This case contributes to the limited literature on internal hernias involving the Pouch of Douglas and emphasizes the need for thorough diagnostic evaluation in complex clinical scenarios.