1. Division of Surgery, Department of Clinical Science, Intervention, and Technology, Karolinska Institutet, Stockholm, Sweden
2. Department of Surgery, Nyköping Hospital, Nyköping, Sweden
3. Centre for Clinical Research Sörmland, Uppsala University, Uppsala, Sweden
4. Department of Clinical Sciences, Danderyds Hospital, Karolinska Institutet, Stockholm, Sweden
5. Department of Surgery and Anaesthesiology, Ersta Hospital, Stockholm, Sweden
6. Department of Upper Abdominal Surgery, Karolinska University Hospital, Stockholm, Sweden
7. Department of Surgery, Odense University Hospital, Odense, Denmark