[1] Osaka Med & Pharmaceut Univ, Dept Gen & Gastroenterol Surg, 2-7 Daigaku Machi, Takatsuki, Osaka 5698686, Japan
[2] Wakayama Med Univ, Second Dept Surg, Wakayama, Japan
[3] Kinki Univ, Fac Med, Dept Surg, Osaka, Japan
[4] Kansai Med Univ, Hirakata Hosp, Dept Surg, Osaka, Japan
[5] Nara Med Univ, Dept Surg, Kashihara, Nara, Japan
[6] Shiga Univ Med Sci, Dept Surg, Otsu, Shiga, Japan
[7] Osaka City Univ, Dept Hepatobiliary Pancreat Surg, Grad Sch Med, Osaka, Japan