Andrea Di Cristofori1, Andrea Gerosa2, Gabriele Panzarasa2. 1. Division of Neurosurgery, University Hospital-Maggiore Hospital of Charity of Novara, Novara, Italy. Electronic address: andrea.dicristofori@gmail.com. 2. Division of Neurosurgery, University Hospital-Maggiore Hospital of Charity of Novara, Novara, Italy.