1. Department of Surgery, Institute of Gastroenterology, Tokyo Women’s Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, Japan
2. Department of Surgery, Ageo Central General Hospital, 1-10-10 Kashiwaza, Ageo-shi, Saitama, Japan
3. Division of General and Gastroenterological Surgery, Department of Surgery (Omori), Toho University School of Medicine, 6-11-1 Ohmori-nishi, Ohta-ku, Tokyo, Japan