^○Tatsuya Orimo, Toshiya Kamiyama, Hideki Yokoo, Kenji Wakayama, Shingo Shimada, Akihisa Nagatsu, Hirofumi Kamachi, Akinobu Taketomi (Department of Gastroenterological Surgery I, Hokkaido University Graduate School of Medicine)

^○Hidetoshi Nitta, Toshihiko Yusa, Yosuke Nakao, Rumi Itoyama, Yuki Kitano, Shigeki Nakagawa, Hirohisa Okabe, Katsunori Imai, Yo-ichi Yamashita, Akira Chikamoto, Hideo Baba (Department of Gastroenterological Surgery, Kumamoto University, Kuamoto Japan)

^○Hayato Abe¹, Yutaka Midorikawa¹, Masahiro Okada², Tadatoshi Takamaya¹ (1.Department of Digestive Surgery, Nihon University School of Medicine, 2.Departments of Radiology, Nihon University School of Medicine)

^○Mitsuhiro Sakaguchi, Naohisa Kuriyama, Aoi Hayasaki, Takehiro Fujii, Yusuke Iizawa, Hiroyuki Kato, Akihiro Tanemura, Yasuhiro Murata, Yoshinori Azumi, Masashi Kishiwada, Shugo Mizuno, Hiroyuki Sakurai, Shuji Isaji (Department of Hepatobiliary Pancreatic and Transplant Surgery, Mie University School of Medicine, Mie, Japan)

^○Keiichi Kubota¹, Taku Aoki¹, Hiraku Kumamaru², Takayuki Shiraki¹, Hiroaki Miyata³, Yasuyuki Seto⁴, Yoshihiro Kakeji⁵, Masakazu Yamamoto⁶ (1.Second Department of Surgery, Dokkyo Medical University, 2.Department of Healthcare Quality Assessment, The University of Tokyo, 3.Department of Health Policy and Management, School of Medicine, Keio University, 4.The Japanese Society of Gastroenterological Surgery, 5.Database Committee, The Japanese Society of Gastroenterological Surgery, 6.The Japanese Society of Hepato-biliary-pancreatic Surgery)