1. Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
2. Department of General and Oncologic Surgery, SS Antonio and Biagio Hospital, Alessandria, University of Turin, Turin, Italy.
3. Robot and MIS Center, Severance Hospital, Yonsei University Health System, Seoul, Korea.
4. Biostatistics Collaboration Unit, Yonsei University College of Medicine, Seoul, Korea.