[1] Univ Thessaly, Fac Med, Sch Hlth Sci, Dept Neurosurg,Univ Hosp Larissa, Larisa, Greece
[2] Hop Univ Geneve, Dept Neurosurg, Geneva, Switzerland
[3] Med Univ Sofia, Sv Ivan Rilski Univ Hosp, Clin Neurosurg, Sofia, Bulgaria
[4] Arnavutkoy State Hosp, Dept Neurosurg, Istanbul, Turkey
[5] Sheffield Teaching Hosp, Neurosurg Dept, Sheffield, England
[6] Leiden Univ, Haaglanden Med Ctr, Dept Neurosurg, Med Ctr, Leiden, Netherlands
[7] Istinye Univ, Med Fac, Dept Neurosurg, Istanbul, Turkey
[8] Univ Med Gottingen, Klin Neurochirurg, Gottingen, Germany
[9] Carol Davila Univ Med, Bucharest Emergency Univ Hosp, Dept Neurosurg, Bucharest, Romania
[10] Nicosia Gen Hosp, Neurosurg Dept, Nicosia, Cyprus
[11] Oulu Univ, Med Res Ctr, Res Unit Clin Neurosci, Oulu, Finland
[12] Univ Hosp Larissa, Dept Neurosurg, Bldg A,3rd Floor, Larisa 41110, Greece