[1] Keio Univ, Sch Med, Keio, Japan
[2] Hiroshima City Hosp, Dept Surg, Hiroshima, Japan
[3] Showa Univ, Koto Toyosu Hosp, Ctr Digest Dis, Tokyo, Japan
[4] Toranomon Gen Hosp, Dept Surg Gastroenterol, Tokyo, Japan
[5] Fujita Hlth Univ, Dept Upper Gastrointestinal Surg, Toyoake, Aichi, Japan
[6] Osaka City Univ, Grad Sch Med, Dept Surg Gastroenterol, Osaka, Japan
[7] Kitasato Univ East Hosp, Dept Gastrointestinal Surg, Sagamihara, Kanagawa, Japan
[8] Keio Univ, Sch Med, Dept Surg, Keio, Japan
[9] Chiba Univ, Dept Esophago Gastro Intestinal Surg, Chiba, Japan
[10] Fukuyama Citizen Hosp, Fukuyama, Hiroshima, Japan
[11] Fujita Hlth Univ, Dept Upper Gastrointestinal Surg, Toyoake, Aichi, Japan
[12] Gunma Univ, Grad Sch Med, Dept Gen Surg Sci, Gunma, Japan