1. Department of Otolaryngology – Head and Neck Surgery Tanta University Tanta Egypt
2. Department of Otolaryngology – Head and Neck Surgery The Ohio State University Wexner Medical Center Columbus Ohio USA
3. Department of Neurological Surgery The Ohio State University Wexner Medical Center Columbus Ohio USA
4. Department of Endocrinology, Diabetes, and Metabolism The Ohio State University Wexner Medical Center Columbus Ohio USA
5. Metabolic Bone Disorders Unit National Institute of Dental and Craniofacial Research, National Institutes of Health Bethesda Maryland USA