1. Otorhinolaryngology Unit, Department of Medical Applications of Laser, National Institute of Laser Enhanced Sciences Cairo University Giza Egypt
2. Klinik für Audiologie und Phoniatrie, Department of Audiology and Phoniatrics Charité—Universitätsmedizin Berlin Berlin Germany
3. Berliner Simulations & Trainingszentrum (BeST), Department of Anatomy Charité—Universitätsmedizin Berlin Berlin Germany