1. Department of Otolaryngology–Head and Neck Surgery University of Iowa Hospitals and Clinics Iowa City Iowa U.S.A.
2. Division of Endocrine and Oncologic Surgery, Department of Surgery Tulane University School of Medicine New Orleans Louisiana U.S.A.
3. Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology Massachusetts Eye and Ear Infirmary and Harvard Medical School Boston Massachusetts U.S.A.
4. Department of Head and Neck Surgical Oncology, National Cancer Institute Cairo University Cairo Egypt