[1] Kansai Med Univ, Hirakata Hosp, Dept Surg, Hirakata, Osaka 5731191, Japan
[2] Osaka City Univ, Grad Sch Med, Dept Hepatobiliary Pancreat Surg, Osaka 5458585, Japan
[3] Osaka Univ, Grad Sch Med, Dept Surg Gastroenterol, Suita, Osaka 5650871, Japan
[4] Osaka Med Coll, Dept Gen & Gastroenterol Surg, Takatsuki, Osaka 5698686, Japan
[5] Kinki Univ, Sch Med, Dept Surg, Osaka 5898511, Japan