1. Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Surgery, Dongsuwon General Hospital, Suwon, Korea.
3. Department of Surgery, Korea University School of Medicine, Seoul, Korea.
4. Department of Surgery, Sungkyunkwan University School of Medicine, Seoul, Korea.
5. Department of Surgery, Catholic University School of Medicine, Seoul, Korea.
6. Department of Surgery, St. Vincent Hospital, Catholic University School of Medicine, Suwon, Korea.
7. Department of Surgery, Hallym University Medical Center, Hallym University College of Medicine, Anyang, Korea.
8. Department of Surgery, Seoul National University Bundang Hospital, Seoul National University School of Medicine, Seongnam, Korea.
9. Department of Surgery, Ajou University School of Medicine, Suwon, Korea.