1. Department of Gastrointestinal Surgery; Vestfold Hospital Trust; Tonsberg Norway
2. Faculty of Medicine; Department of Cellular Physiology and Metabolism; Anatomy Sector; University of Geneva; Geneva Switzerland
3. Department of Digestive Surgery; Akershus University Hospital; University of Oslo; Lorenskog Norway
4. Institute of Clinical Medicine; University of Oslo; Oslo Norway
5. Interventional Centre; Gastrointestinal and Pediatric Surgery; Oslo University Hospital-Rikshospitalet; Oslo Norway