1. Division of Digestive Surgery and Urology, Turku University Hospital, Turku, Finland
2. Department of Surgery, University of Turku, Turku, Finland
3. Department of Surgery, Satakunta Central Hospital, Pori, Finland
4. Department of Surgery, Oulu University Hospital, Oulu, Finland
5. Medical Research Center Oulu, University of Oulu, Finland
6. Department of Gastroenterology and Alimentary Tract Surgery, Tampere University Hospital, Tampere, Finland
7. Faculty of Medicine and Health Technology, University of Tampere, Tampere, Finland
8. Department of Surgery, Kuopio University Hospital, Kuopio, Finland
9. Department of Surgery, Institute of Clinical Medicine, University of Eastern Finland
10. Department of Surgery, Seinäjoki Central Hospital, Seinäjoki, Finland
11. Department of Surgery, Mikkeli Central Hospital, Mikkeli, Finland
12. Department of Surgery, Jyväskylä Central Hospital, Jyväskylä, Finland
13. Department of Surgery, Rovaniemi Central Hospital, Rovaniemi, Finland
14. Department of Biostatistics, University of Turku, Turku, Finland
15. Department of Radiology, Turku University Hospital, Turku, Finland
16. Department of Hospital Hygiene & Infection Control, Turku University Hospital, Turku, Finland