1. Department of Clinical Research, University of Basel, Basel, Switzerland
2. Claraunis, Department of Visceral Surgery, University Centre for Gastrointestinal and Liver Diseases, St Clara Hospital and University Hospital Basel, Basel, Switzerland
3. Department of Biostatistics, University of Turku and Turku University Hospital, Turku, Finland
4. Department of Surgery, University of Turku, Turku, Finland
5. Department of Surgery and Transplantation, University Hospital Zurich, University of Zurich, Zurich, Switzerland
6. Department of Surgery, Männedorf Hospital, Männedorf, Switzerland
7. Division of Digestive Surgery and Urology, Turku University Hospital, Turku, Finland