Radical Resection of the Third Portion of the Duodenum for Secondary Aortoduodenal Fistula

ABSTRACT Secondary aortoduodenal fistula (sADF) is a rare but life‐threatening complication following abdominal aortic aneurysm repair. Its management requires multidisciplinary collaboration; however, even gastrointestinal surgeons—who play a pivotal role in duodenal resection and reconstruction—often lack sufficient experience with this condition. Therefore, a clear understanding of sADF is essential for gastrointestinal surgeons. We retrospectively analyzed 16 sADF patients who underwent combined vascular and gastrointestinal reconstruction at Shinshu University Hospital between September 2018 and December 2025. We describe our step‐by‐step approach to radical resection of the third portion of the duodenum performed in collaboration with cardiovascular surgeons. The procedure includes complete division of the Treitz ligament, mobilization of the fourth portion from the uncinate process, preservation of the papilla of Vater, en bloc resection of the involved segment, and duodenojejunostomy. The greater omentum is mobilized through a retrocolonic route to facilitate secure graft coverage following vascular reconstruction. Postoperative course, complications, and survival rates were evaluated. The median age was 75 years (range: 67–83 years). The median operation time was 651 min (range 481–1477 min), and the median blood loss was 3050 mL (range 850–15 000 mL). Severe postoperative complications (Clavien–Dindo classification grade IIIa or higher) occurred in 10 patients (63%), and the 90‐day mortality rate was 21%. The 1‐year overall survival rate was 57%. Careful multidisciplinary coordination and precise gastrointestinal surgical technique are essential for achieving safe and durable management of this complex condition.