1. Department of Urology and Pediatric Urology, University Hospital of Würzburg, Julius-Maximilians University, Wuerzburg, Germany;
2. Department of Urology, University Hospital of Würzburg, Eberhard-Karls University, Tuebingen, Germany;
3. Department of ENT, University Hospital of Würzburg, Julius-Maximilians University, Wuerzburg, Germany