[1] Fujita Hlth Univ, Sch Med, Dept Gen & Gastrointestinal Surg, Nakagawa Ku, Aichi 4548509, Japan
[2] Hino Municipal Hosp, Dept Surg, Tokyo, Japan
[3] Osaka Med Coll, Dept Internal Med 2, Osaka, Japan
[4] Osaka City Univ, Grad Sch Med, Dept Gastroenterol, Osaka 558, Japan
[5] Hokkaido Univ Hosp, Div Endoscopy, Sapporo, Hokkaido 060, Japan
[6] Hokkaido Univ, Dept Gastroenterol & Hematol, Grad Sch Med, Sapporo, Hokkaido, Japan
[7] Kitasato Univ, Sch Med, Dept Surg, Kanagawa, Japan
[8] Gunma Univ, Grad Sch Med, Dept Gen Surg Sci, Gunma, Japan
[9] Int Univ Hlth, Dept Surg, Minato Ku, Tokyo, Japan
[10] Welf Mita Hosp, Minato Ku, Tokyo, Japan