1. Department of Surgery, Eunpyeong St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
2. Department of Surgery, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea
3. Department of Surgery, Dong-A University Hospital, College of Medicine, Dong-A University, Busan, Korea
4. Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea