1. Swiss Hepato-Pancreato-Biliary Centre, Department of Surgery, University Hospital, Zurich, Switzerland
2. Swiss Hepato-Pancreato-Biliary Centre, Department of Horten Centre for Patient Oriented Research, University Hospital, Zurich, Switzerland
3. Swiss Hepato-Pancreato-Biliary Centre, Department of Gastroenterology and Hepatology, University Hospital, Zurich, Switzerland