[1] Univ Dusseldorf, Dept Urol, D-40225 Dusseldorf, Germany
[2] Univ Bonn, Dept Urol, D-5300 Bonn, Germany
[3] Charite, Dept Urol, Berlin, Germany
[4] Univ Homburg, Dept Urol, D-6650 Homburg, Germany
[5] St Vincenz Hosp, Dept Urol, Datteln, Germany
[6] Univ Aachen, Dept Urol, D-5100 Aachen, Germany
[7] Univ Bonn, Inst Med Biometry Informat & Epidemiol, D-5300 Bonn, Germany