Afferent loop obstruction Article Pancreaticoduodenectomy Percutaneous transhepatic biliary drainage Stents abdominal radiography adenocarcinoma adult afferent loop syndrome antineoplastic agent balloon catheterization biliary cannulation biliary tract drainage cancer size case report cholangiography clinical article computer assisted tomography disease exacerbation duodenum carcinoma duodenum stenosis endoscopic surgery histopathology hospital discharge human iohexol magnetic resonance cholangiopancreatography male middle aged mortality