1. Department of Surgery, Chung-Ang University College of Medicine, Seoul, Korea.
2. Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Surgery, Korea University College of Medicine, Seoul, Korea.
4. Department of Surgery, Hallym University College of Medicine, Chuncheon, Korea.
5. Department of Surgery, University of Ulsan College of Medicine, Ulsan, Korea.
6. Department of Surgery, Chungbuk National University College of Medicine and Medical Research Institute, Cheongju, Korea.
7. Department of Surgery, Kosin University College of Medicine, Busan, Korea.
8. Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
9. Department of Surgery, Catholic University College of Medicine, Seoul, Korea.
10. Department of Surgery, Sungkyunkwan University College of Medicine, Seoul, Korea.