1) Department of Gastroenterological Surgery, Hirosaki University, Hirosaki, Japan
2) Department of Gastroenterological Surgery Ⅱ, Hokkaido University, Sapporo, Japan
3) Department of Surgery and Science, Kyushu University, Fukuoka, Japan

Kenichi Hakamada¹⁾, Satoshi Hirano²⁾, Eiji Oki³⁾