1. Department of Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Rehabilitation Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
3. Department of Surgery, Inje University Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
4. Department of Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.
5. Department of Department of Occupational and Environmental Medicine, Seoul St. Mary's Hospital, The Catholic University College of Medicine, Seoul, Korea.