[1] Univ Turin, Dept Neurosci Rita Levi Montalcini, Unit Neurosurg, I-10126 Turin, Italy
[2] Humanitas Gradenigo Hosp, Neurosurg Spine Surg, Turin, Italy
[3] Univ Catania, Policlin G Rodolico San Marco Univ Hosp, Dept Med & Surg Sci & Adv Technol GF Ingrassia, Neurol Surg, Catania, Italy
[4] Catholic Univ, Fdn Policlin Univ A Gemelli Irccs, Inst Neurosurg, Rome, Italy
[5] Mater Olbia Hosp, Dept Neurosurg, Olbia, Italy
[6] Ist Clin Citta, Unit Neurosurg, Milan, Italy