1. Department of Surgery, Enköping Hospital, Enköping, Sweden.
2. Division of Surgery, Department of Clinical Sciences, Intervention and Technology (CLINTEC), Karolinska Institute, Stockholm, Sweden.
3. Department of Surgery, Västerås Hospital, Västerås, Sweden.
4. Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
5. Department of Surgery, University Hospital, Uppsala, Sweden.