1. Department of Urology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan
2. Center for Innovative Clinical Medicine, Okayama University Hospital, Okayama University, Okayama 700-8558, Japan
3. Department of Urology, Kawasaki Medical School, Kurashiki 701-0192, Japan