1. Interventional Neuroradiology of the Neurology and Neurosurgery Service; Passo Fundo, Brazil
2. Neurosurgery Department, São Vicente de Paulo University Hospital; Passo Fundo, Brazil
3. Neurosurgery Department, Federal University of São Paulo; São Paulo, Brazil
4. Department of Medicine, Passo Fundo University; Passo Fundo, Brazil