1. Faculty of Medicine, Damascus University, Damascus, Syrian Arab Republic
2. Faculty of Medicine, University of Kalamoon, Deir Atieh, Syrian Arab Republic
3. Ruprecht Karls University Heidelberg, Medical Faculty Mannheim, Germany
4. Department of Otorhinolaryngology-Head and Neck Surgery, Mannheim Medical Center, Mannheim, Germany
5. The University of Pittsburgh, Department of Plastic Surgery, Pittsburgh, USA