1. Department of Surgery, The Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, Korea.
2. Department of Surgery, The Catholic University of Korea, Daejeon St. Mary's Hospital, Daejeon, Korea.
3. Department of Surgery, The Catholic University of Korea, Uijeongbu St. Mary's Hospital, Uijeongbu, Korea.
4. Department of Internal Medicine, The Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, Korea.