[1] Harvard Med Sch, Brigham & Womens Hosp, Dept Neurosurg, Boston, MA USA
[2] Harvard Med Sch, Boston Childrens Hosp, Dept Neurosurg, Boston, MA USA
[3] Harvard Med Sch, Boston Childrens Hosp, Dept Intervent Neuroradiol, Boston, MA USA
[4] St Josephs Med Ctr, Barrow Neurol Inst, Dept Neurosurg, Phoenix, AZ USA
[5] Univ Arizona, Banner Univ Med Ctr, Dept Neurosurg, Tucson, AZ USA
[6] Brigham & Womens Hosp, Boston, MA 02115 USA