Pathogenic Synergy in Intestinal Obstruction: Incomplete Malrotation, Cholecystoduodenal Fistula, and Gallstone Ileus

Incomplete intestinal malrotation (IIM) is a congenital anomaly of embryonic gut rotation, usually asymptomatic in adults, while gallstone ileus and cholecystoduodenal fistulas represent rare complications of chronic cholelithiasis.We report an unusual case of acute distal intestinal obstruction in a 71-year-old female patient, revealing an IIM with an incomplete obstructive Ladd's band, complicated indirectly by a tubulated cholecystoduodenal fistula causing gallstone ileus.A 71-year-old female patient with no baseline hemodynamic instability or systemic decompensation was admitted for acute distal intestinal obstruction.Her symptoms presented with a paroxysmal pattern, characterized by colicky epigastric pain accompanied by bilious and partially digested emesis.Her medical history was notable for prior episodes of biliary colic.Laboratory workup revealed normal serum lactate levels, effectively ruling out overt bowel ischemia or advanced tissue compromise at this stage, while upper gastrointestinal (GI) series and abdominal computed tomography (CT) scan revealed a "double-bubble" sign, severe duodenal ectasia (15 cm), aerobilia, and an impacted intraluminal gallstone.Emergency exploratory laparotomy confirmed the diagnosis, with surgical management including section of Ladd's band with complete duodenal mobilization, enterolithotomy with transverse enteroraphy to extract the stone, and a prophylactic appendectomy.Given the inactive nature of the fistula and the emergency setting, conservative management of the biliary fistula was selected, leading to an uneventful postoperative course with bowel transit recovery on day 3 and complete clinical recovery.This observation highlights an unprecedented obstructive synergy, wherein chronic duodenal stasis caused by Ladd's band promoted local hyperpressure and inflammation, accelerating cholecystoduodenal fistula formation and subsequent gallstone ileus, demonstrating that in emergency settings, surgical priority must focus on immediate relief of the intestinal obstruction.Ultimately, the combination of Ladd's band and gallstone ileus is exceptionally rare, and emergency surgical treatment should focus on relieving mechanical obstruction, while conservative management of an inactive fistula remains a safe option in elderly patients.