1. Department of Gastrointestinal Surgery, Stavanger University Hospital , Stavanger , Norway
2. SAFER Surgery, Surgical Research Group, Stavanger University Hospital , Stavanger , Norway
3. Department of Clinical Medicine, University of Bergen , Bergen , Norway
4. Department of Surgery, Vascular Surgery Unit, Stavanger University Hospital , Stavanger , Norway
5. Department of Clinical Science, University of Bergen , Bergen , Norway