1. Clinic of Pediatric Surgery, Clinic St. Hedwig, Barmherzige Brüder Regensburg, Regensburg, Germany
2. Clinic of Pediatric and Adolescent Medicine, Clinic St. Hedwig, Barmherzige Brüder Regensburg, Regensburg, Germany
3. Department of Trauma Surgery, University Medical Center Regensburg, Regensburg, Germany
4. Department of Otorhinolaryngology, Head and Neck Surgery, Paracelsus Medical University, General Hospital Nuernberg, Nuremberg, Germany