1 Neurosurgery Department, IRCCS Fondazione Policlinico San Matteo, Pavia, Italy.
2 National Center of Oncological Hadrontherapy (CNAO) Clinical Radiotherapy Unit, Pavia, Italy.
3 Neurosurgery Unit, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, IRCCS Fondazione Policlinico San Matteo, University of Pavia, Pavia, Italy.