1. Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Surgery, CHA Bundang Medical Center, CHA University, Seongnam, Korea.
4. Division of Colon and Rectal Surgery, Department of Surgery, Ajou University School of Medicine, Suwon, Korea.