1. Department of Gastrointestinal Surgery, University Hospital of North, Tromsø, Norway
2. Institute of Clinical Medicine, Arctic University of Norway, Tromsø, Norway
3. Department of Hepatobiliary and Pancreatic Surgery, Oslo University Hospital, Oslo, Norway
4. Institute of Clinical Medicine, University of Oslo, Oslo, Norway
5. Department of Gastrointestinal Surgery, Haukeland University Hospital, Bergen, Norway
6. Department of Gastrointestinal Surgery, St Olav Hospital, Trondheim University Hospital, Trondheim, Norway
7. Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
8. Department of Clinical Medicine, University of Bergen, Bergen, Norway
9. Department of Gastrointestinal Surgery, Stavanger University Hospital, Stavanger, Norway