1. Department of Surgery, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
3. Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
5. Department of Surgery, Keimyung University College of Medicine, Daegu, Korea.