1. Department of Skull Base Surgery, Clinica Bio Bio, Concepción, Chile
2. Department of Neurological Surgery, Hospital Clinico Regional de Concepción, Concepción, Chile
3. Department of Otolaryngology, Instituto de Nuerologia de Curitiba, Curitiba, PR, Brazil
4. Department of Neurosurgery, Instituto de Neurologia de Curitiba, Curitiba, PR, Brazil