1. Department of Surgery, Hepato-Biliary Pancreatic Surgery Division, National Center for Global Health and Medicine, Tokyo, Japan.
2. Department of Hepatobiliary Pancreatic Surgery, Juntendo University Hospital, Tokyo, Japan.
3. Department of Hepatobiliary and Pancreatic Surgery, Cancer Institute Hospital, Tokyo, Japan.
4. Department of Surgery, Upper Abdominal Surgery Division, National Center for Global Health and Medicine, Tokyo, Japan.