1. Post-Graduation Program, State University of Ponta Grossa, Ponta Grossa, Paraná, Brazil.
2. Department of Neurosurgery, Santa Casa of Passos Hospital, Passos, Minas Gerais, Brazil.
3. Department of Neurosurgery. School of Medicine. University of Sao Paulo, Sao Paulo, Brazil.
4. Department of Neurological Surgery, State University of Ponta Grossa, Leonardo Welling, Ponta Grossa, Parana, Brazil.