1. Microneurosurgery Laboratory, Institute of Neurological Sciences, Hospital Beneficência Portuguesa de São Paulo;
2. Division of Neurosurgery, School of Medicine, University Nove de Julho, São Paulo;
3. Division of Neurosurgery, School of Medicine, State University of Campinas, Brazil
4. Clinical Anatomy Discipline, Department of Surgery–Laboratório de Investigação Médica–02, University of São Paulo Medical School;
5. Hospital Israelita Albert Einstein, São Paulo; and