1. Department of Urology, Kyung Hee University Medical Center, Kyung Hee University College of Medicine, Seoul, Korea.
2. Department of Urology, Kyung Hee University Hospital at Gangdong, Kyung Hee University College of Medicine, Seoul, Korea.
3. Department of Urology, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Korea.