[1] SUNY Stony Brook, Dept Neurosurg, Stony Brook, NY 11794 USA
[2] Oxford Radcliffe Hosp, Oxford Neurovasc & Neuroradiol Res Unit, Oxford, England
[3] Johns Hopkins Univ, Sch Med, Johns Hopkins Hosp, Baltimore, MD USA
[4] Natl Inst Neurosci, Budapest, Hungary
[5] Private Koru Hosp, Ankara, Turkey
[6] Marmara Univ, Fac Med, Pendik Training & Res Hosp, Istanbul, Turkey
[7] Brigham & Womens Hosp, Dept Neurosurg, 75 Francis St, Boston, MA 02115 USA
[8] Univ Tennessee, Dept Neurosurg, Semmes Murphey Neurol & Spine Inst, 6325 Humphreys Blvd, Memphis, TN 38120 USA