[1] Evangelismos Gen Hosp, Dept Neurosurg, Ipsilantou 45-47, Athens 10676, Greece
[2] Democritus Univ Thrace, Dept Neurosurg, Alexandroupolis, Greece
[3] Med Univ Thessaly, Dept Med, Larisa, Greece
[4] Democritus Univ Thrace, Dept Stat, Alexandroupolis, Greece
[5] Democritus Univ Thrace, Dept Surg, Alexandroupolis, Greece