Ioannis D Siasios1, Vassilios G Dimopoulos1, Kostas N Fountas2. 1. Department of Neurosurgery, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, USA; ; Department of Neurosurgery, Buffalo General Medical Center, School of Medicine, University of Thessaly, Larisa, Greece. 2. Department of Neurosurgery, School of Medicine, University of Thessaly, Larisa, Greece.