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