1. Abdominal Center, Gastroenterological Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
2. Department of Gastrointestinal Surgery, Oulu University Hospital, Oulu, Finland
3. Department of Gastrointestinal Surgery, Aalborg University Hospital, Aalborg, Denmark
4. Abdominal Center, Gastroenterology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
5. Department of Gastroenterology and Hepatology, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
6. Department of Upper Gastrointestinal Diseases, Karolinska University Hospital, Stockholm, Sweden
7. Department of Gastroenterology, Oslo University Hospital, Oslo, Norway
8. Department of Medical Gastroenterology, Rikshospitalet University Hospital, Oslo, Norway
9. Division of Digestive Surgery and Urology, Turku University Hospital and University of Turku, Turku, Finland