1. Department of Surgery, Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Seoul, Korea
2. Department of Surgery, Seoul Medical Center, Seoul, Korea
3. Naeungil Clinic, Seongdong-gu, Seoul, Korea
4. Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
5. Department of Surgery, Ewha Womans University College of Medicine, Ewha Womans University Medical Center, Seoul, Korea
6. Department of Radiology, Soonchunhyang University Gumi Hospital, Gumi, Korea
7. Division of Nephrology, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea