1. Department of Neurosurgery, Hospital de San José - Fundación Universitaria de Ciencias de la Salud, Bogota, Colombia,
2. Department of Neurosurgery, Mayo Clinic, Jacksonville, Florida, USA,
3. Department of Neurosurgery, Faculty of Medicine, Medical University of Plovdiv, Plovdiv, Bulgaria,
4. Department of Neurosurgery, School of Medicine, Hospital de San José - Fundación Universitaria de Ciencias de la Salud, Bogota, Colombia.