1. Department of Surgery, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea.
2. Department of Surgery, Inje University Busan Paik Hospital, Busan, Korea.
3. Department of Surgery, Chonbuk National University Hospital, Jeonju, Korea.
4. Department of Surgery, Ajou University School of Medicine, Suwon, Korea.
5. Department of Surgery, Inje University Sanggye Paik Hospital, Seoul, Korea.
6. Department of Surgery, Presbyterian Medical Center, Jeonju, Korea.
7. Department of Surgery, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Korea.