1. Department of Surgery, Skåne University Hospital , Malmö , Sweden
2. Department of Clinical Sciences Malmö, Lund University , Malmö , Sweden
3. Department of Surgery, Erasmus University Medical Centre , Rotterdam , The Netherlands
4. Department of Surgery, University Medical Centre Amsterdam, AMC , Amsterdam , The Netherlands
5. Faculty of Medicine, Institute of Clinical Medicine, University of Oslo , Oslo , Norway
6. Department of Gastrointestinal Surgery, Oslo University Hospital , Oslo , Norway
7. Department of Digestive Surgery, Akershus University Hospital , Lørenskog , Norway