Eun Jung Park1, Suk Jun Lee2, Seung Hyuk Baik3. 1. Division of Colon and Rectal Surgery, Department of Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea. camp79@yuhs.ac. 2. Department of Surgery, Yonsei University College of Medicine, Seoul, Korea. 3. Division of Colon and Rectal Surgery, Department of Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.