1 Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seodaemun-gu, Seoul, South Korea.
2 Department of Surgery, Yongin Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
3 Department of Surgery, National Health Insurance Service Ilsan Hospital, Ilsan, South Korea.
4 Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seodaemun-gu, Seoul, South Korea. drhhk@yuhs.ac.