1. Department of Surgery, Ajou University School of Medicine, Suwon, Korea.
2. Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
3. Department of Surgery, Yeungnam University College of Medicine, Daegu, Korea.
4. Department of Surgery, Gachon University of Medical and Science, Incheon, Korea.
5. Department of Surgery, Inha University College of Medicine, Incheon, Korea.