[1] Univ Edinburgh, Edinburgh, Midlothian, Scotland
[2] Univ Athens, Dept Neurosurg, Evangelismos Hosp, Ipsilantou 45-47, Athens 10676, Greece
[3] Western Gen Hosp, Dept Clin Neurosci, Edinburgh, Midlothian, Scotland
[4] Hellen Ctr Neurosurg Res Prof Petros Kokkalis, Athens, Greece
[5] Cleveland Clin Fdn, Lerner Res Inst, 9500 Euclid Ave, Cleveland, OH 44195 USA