1. Division of Facial Plastic and Reconstructive Surgery, Stanford University School of Medicine, Stanford, California, USA.
2. Department of Maxillofacial and Plastic Surgery, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
3. Albany Medical College, Albany, New York, USA.
4. Department of Otorhinolaryngology, Head & Neck Surgery, Faculty of Medicine, Kafrelsheikh University, Kafrelsheikh, Egypt.