1. Department of Gastrointestinal Surgery, Østfold Hospital Trust , Grålum, Norway
2. Institute for Clinical Medicine, University of Oslo , Oslo, Norway
3. Interventional Centre, Oslo University Hospital—Rikshospitalet , Oslo, Norway
4. Department of Surgery, Fonna Hospital Trust , Odda, Norway
5. Department of Faculty Surgery, I. M. Sechenov First Moscow State Medical University , Moscow, Russia
6. Department of Surgery N 2, Yerevan State Medical University After M. Heratsi , Yerevan, Armenia
7. Anatomy Sector, Teaching Unit, Faculty of Medicine, University of Geneva , Geneva, Switzerland
8. Department of Gastrointestinal and Paediatric Surgery, Oslo University Hospital—Rikshospitalet , Oslo, Norway
9. Department of Digestive Surgery, Akershus University Hospital , Lørenskog, Norway