[1] Mie Univ, Grad Sch Med, Dept Hepatobiliary Pancreat Surg & Breast Surg, Tsu, Mie 5148507, Japan
[2] Teikyo Univ, Sch Med, Dept Surg, Tokyo 173, Japan
[3] Ueno Municipal Hosp, Ueno, Mie, Japan
[4] Sapporo Med Univ, Sch Med, Dept Surg 1, Sapporo, Hokkaido, Japan
[5] Nagoya Univ, Grad Sch Med, Dept Emergency & Crit Care Med, Nagoya, Aichi, Japan
[6] Kyoto Univ, Grad Sch Med, Dept Healthcare Econ & Qual Management, Kyoto, Japan
[7] Kumamoto Univ, Grad Sch Med Sci, Dept Surg Gastroenterol, Kumamoto, Japan
[8] Natl Hosp Org Sendai Med Ctr, Dept Surg, Sendai, Miyagi, Japan
[9] Ohara Med Ctr Hosp, Fukushima, Japan
[10] Univ Occupat & Environm Hlth, Sch Med, Dept Gastroenterol & Metab, Kitakyushu, Fukuoka 807, Japan
[11] Tohoku Univ, Grad Sch Med, Div Gastroenterol Surg, Sendai, Miyagi 980, Japan