1. Department of Clinical Sciences, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
2. Department of Surgery, Mora Hospital, Mora, Sweden
3. Center for Clinical Research, Uppsala University, Falun, Sweden
4. Department of Clinical Science and Education, South General Hospital, Karolinska Institutet, Stockholm, Sweden
5. Department of Surgical and Perioperative Sciences, Surgery, Umeå University, Umeå, Sweden
6. Department of Surgery, Sunderby Hospital, Luleå, Sweden