Tetsuya TsukaharaNational Hospital Organization, Kyoto Medical Center, Mukaihata-cho 1, 612-8555 Fukakusa,Fushimi-ku, Kyoto, JapanAlberto PasqualinVerona City Hospital, Institute of Neurosurgery, Piazzale Stefani 1, 37100 Verona, ItalyGiuseppe Esposito, MD, PhDConsultant Neurosurgeon, Department of Neurosurgery, University Hospital Zurich, Frauenklinikstrasse 10, 8091 Zurich, SwitzerlandLuca RegliUniversity Hospital Zurich, Department of Neurosurgery, Frauenklinikstrasse 10, 8091 Zurich, SwitzerlandGiampietro PinnaVerona City Hospital, Institute of Neurosurgery, Piazzale Stefani 1, 37100 Verona, Italy