András Horváth1, István Valálik2, András Csókay3. 1. Semmelweis University Faculty of Medicine, Budapest, Hungary ; 36, Vincellér street, Szekszárd, 7100 Hungary. 2. Department of Neurosurgery, St. John's Hospital, Budapest, Hungary. 3. Department of Neurosurgery, BAZ County Hospital, Miskolc, Hungary.