1. Department of Surgery, Division of Hepato-Biliary-Pancreatic Surgery, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo-ku, Kobe City, Hyogo, Japan
2. Department of Surgery, National Hospital Organization Kobe Medical Center, Nishi-Ochiai, Suma-ku, Kobe City, Hyogo, Japan
3. Department of Surgery, Division of Gastroenterological Surgery, Hyogo Cancer Center, Kita-Ojicho, Akashi City, Hyogo, Japan