1. Department of Surgery, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
2. Department of Surgery, Kyung Hee University Medical Center, Kyung Hee University School of Medicine, Seoul, Korea.
3. Department of Surgery, Cheil General Hospital and Women's Healthcare Center, Kwandong University College of Medicine, Seoul, Korea.
4. Department of Social and Preventive Medicine, Inha University School of Medicine, Incheon, Korea.
5. Department of Surgery, Inje University Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
6. Department of Surgery, Chonbuk National University Medical School, Jeonju, Korea.
7. Department of Surgery, Gachon University Gil Medical Center, Incheon, Korea.
8. Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.