1. Departament of Neurosurgery, Hospital da Restauração, Recife, Brazil.
2. College of Medical Sciences, Unifacisa University Center, Campina Grande, Paraíba, Recife, Brazil.
3. Catholic University of Pernambuco, Recife, Brazil.
4. Oswaldo Cruz University Hospital, University of Pernambuco, Recife, Brazil.
5. Regional Hospital of Presidente Prudente, Sao Paulo, Brazil.
6. College of Medical Sciences, Federal University of Paraíba, João Pessoa, Brazil.