1. Department of Surgery, Seoul St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
2. Department of Surgery, St Vincent’s Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea
3. Department of Surgery, Ajou University Hospital, Suwon, Korea
4. Department of Surgery, Uijeongbu St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Korea
5. Department of Surgery, Kyung Hee University Hospital at Gangdong, Kyung Hee University College of Medicine, Seoul, Korea
6. Department of Surgery, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon, Korea
7. Department of Surgery, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea
8. Department of Surgery, Chonnam National University Hospital, College of Medicine, Chonnam National University, Gwangju, Korea
9. Department of Surgery, Yeouido St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
10. Department of Surgery, Keimyung University and Dongsan Medical Center, Daegu, Korea
11. Department of Surgery, Seoul National University Bundang Hospital, Seongnam, Korea
12. Department of Surgery, National Health Insurance Service, Ilsan Hospital, Goyang, Korea
13. Department of Surgery, EunPyeong St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea