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