1. Department of Neurosurgery, Emory University, Atlanta, Georgia, USA;
2. Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, Georgia, USA;
3. Department of Otolaryngology, Emory University, Atlanta, Georgia, USA;
4. Department of Neurosurgery, Hospital Universitario San Ignacio, Pontificia Universidad Javeriana, Bogota, Colombia