1. Department of Urology; Charité, University Medicine Berlin; Berlin Germany
2. Department of Urology; University Hospital Cologne; Cologne Germany
3. Department of Urology; Weiden Hospital; Weiden Germany
4. Department of Urology; University Hospital Düsseldorf; Düsseldorf Germany
5. Department of Urology; Hospital Bremen-Mitte; Bremen Germany
6. Institute for Clinical Epidemiology and Applied Biometrics; Tübingen University Hospital; Tübingen Germany