Bile Ducts, Intrahepatic; Biliary Tract Diseases; Biliary Tract Surgical Procedures/methods; Dilatation; Postoperative Complications; Reinfection; Aged, 80 and over; Bile Ducts, Intrahepatic/diagnostic imaging; Bile Ducts, Intrahepatic/pathology; Bile Ducts, Intrahepatic/surgery; Biliary Tract Diseases/diagnosis; Biliary Tract Diseases/etiology; Biliary Tract Diseases/physiopathology; Biliary Tract Diseases/surgery; Cholangiopancreatography, Endoscopic Retrograde/methods; Common Bile Duct Neoplasms/surgery; Constriction, Pathologic/diagnosis; Constriction, Pathologic/etiology; Constriction, Pathologic/surgery; Dilatation/instrumentation; Dilatation/methods; Gram-Negative Bacterial Infections; Humans; Long Term Adverse Effects; Male; Pancreaticoduodenectomy/adverse effects; Postoperative Complications/microbiology; Postoperative Complications/physiopathology; Postoperative Complications/therapy; Reinfection/diagnosis; Reinfection/etiology; Reinfection/physiopathology; Sepsis/microbiology; Sepsis/physiopathology; Stents; Treatment Outcome