[1] Univ Hosp Mannheim, Dept Otorhinolaryngol Head & Neck Surg, D-68167 Mannheim, Germany
[2] Univ Munich, Dept Otorhinolaryngol Head & Neck Surg, Munich, Germany
[3] Tech Univ Munich, Klinikum Rechts Isar, Dept Otorhinolaryngol Head & Neck Surg, D-80290 Munich, Germany
[4] Univ Halle Wittenberg, Dept Otorhinolaryngol Head & Neck Surg, D-06108 Halle, Germany
[5] Univ Hosp, Dept Otorhinolaryngol Head & Neck Surg, Regensburg, Germany
[6] German Assoc Craniomaxillofacial Surg, Erfurt, Germany
[7] Inst Surg Res, Marburg, Germany
[8] Med Univ Lubeck, Dept Otorhinolaryngol Head & Neck Surg, D-23538 Lubeck, Germany
[9] Asklepios Klin Harburg, Dept Otorhinolaryngol Head & Neck Surg, Hamburg, Germany