1 Department of Urology, Kim Jong Sung Urological Clinic, Iksan, Republic of Korea.
2 Department of Urology, Chonbuk National University Medical School, Institute for Medical Sciences, Chonbuk National University and Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Republic of Korea. Electronic address: ball1210@hanmail.net.
3 Department of Urology, Chonbuk National University Medical School, Institute for Medical Sciences, Chonbuk National University and Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Republic of Korea.