[1] Osaka Metropolitan Univ, Dept Hepatobiliary Pancreat Surg, Grad Sch Med, 1-4-3 Asahimachi, Abeno Ku, Osaka 5458585, Japan
[2] Osaka Univ, Grad Sch Med, Dept Gastroenterol Surg, Suita, Osaka, Japan
[3] Osaka Med & Pharmaceut Univ, Dept Gen & Gastroenterol Surg, Takatsuki, Osaka, Japan
[4] Kansai Med Univ, Hirakata Hosp, Dept Surg, Hirakata, Osaka, Japan
[5] Shiga Univ Med Sci, Dept Surg, Div Gastrointestinal Breast & Gen Surg, Otsu, Japan
[6] Wakayama Med Univ, Dept Surg 2, Wakayama, Japan
[7] Nara Med Univ, Dept Surg, Kashihara, Nara, Japan
[8] Kyoto Prefectural Univ Med, Dept Surg, Kyoto, Japan
[9] Kindai Univ, Fac Med, Dept Surg, Osaka, Osaka, Japan
[10] Osaka Metropolitan Univ, Dept Med Stat, Grad Sch Med, Osaka, Japan