1. Neurosurgery Unit, Bufalini Hospital, 47521 Cesena, Italy
2. NESMOS Department, “Sapienza” University of Rome, Sant’Andrea Hospital, 00185 Rome, Italy
3. Neurosurgery Unit, Cardinale G. Panico Hospital, 73039 Tricase, Italy
4. Department of Neurosurgery, S. Anna University Hospital, 44124 Ferrara, Italy
5. Department of Neurosurgery, University of Pisa, 56126 Pisa, Italy