1. Department of Surgery, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea.
2. Department of Surgery, Chuncheon Sacred Heart Hospital, Hallym University, Chuncheon, Korea.
3. Department of Surgery, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Korea.
4. Department of Surgery, Daejeon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Daejeon, Korea.
5. Department of Surgery, Kyung Hee Medical Center, Kyung Hee University School of Medicine, Seoul, Korea.
6. Department of Surgery, Chonnam National University Hwasun Hospital, Chonnam National University School of Medicine, Hwasun, Korea.
7. Department of Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.