Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan. taitoh1128@gmail.com. Department of Surgery, Kurashiki Medical Center, Bakuro-cho, Kurashiki, Okayama, 710-8522, Japan. taitoh1128@gmail.com. Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan. Laboratory of Head and Neck Surgery, Ehime Prefectural University of Health Sciences, 543, Takoda, Tobe-cho, Iyo-gun, Ehime, 791-2101, Japan.