1. Department of Surgery Karlstad Hospital Karlstad Sweden
2. Department of Surgery SSORG – Scandinavian Surgical Outcomes Research Group Institute of Clinical Sciences Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
3. Department of Surgery Region Västra Götaland Sahlgrenska University Hospital Gothenburg Sweden
4. Department of Surgery Faculty of Medicine and Health Örebro University Örebro Sweden
5. Department of Surgery Herlev Hospital University of Copenhagen Herlev Denmark