Case Report: A rare cause of acute abdomen: retrograde efferent loop intussusception into the gastric remnant following Billroth II gastrectomy

This paper reports a special case in which retrograde intussusception of the efferent loop through the gastrojejunostomy into the gastric remnant led to closed-loop intestinal obstruction and small bowel ischemia. The patient was a 69-year-old male with a history of subtotal gastrectomy, who was admitted for acute abdominal pain. Initial computed tomography (CT) findings were inconclusive, while contrast-enhanced CT suggested the possibility of intussusception. Emergency surgery confirmed the diagnosis, and the patient underwent gastrotomy with reduction, followed by partial small bowel resection and anastomosis. The postoperative recovery was uneventful. This case highlights the rare location, diagnostic challenges, and the importance of multidisciplinary management in postgastrectomy internal hernia/intussusception. Based on a literature review, we provide an in-depth discussion of its pathogenesis, imaging characteristics, and surgical management strategies.