1. Department of Surgery, Ajou University School of Medicine, Suwon, Korea.
2. Department of Medical Informatics, Ajou University School of Medicine, Suwon, Korea.
3. Department of Surgery, Eulji University College of Medicine, Daejeon, Korea.
4. Department of Surgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
5. Department of Surgery, the Catholic University College of Medicine, Seoul, Korea.
6. Department of Surgery, Kwandong University School of Medicine, Goyang, Korea.