[1] Thomas Jefferson Univ, Dept Neurosurg, Philadelphia, PA 19107 USA
[2] Thomas Jefferson Univ, Dept Neurol, Philadelphia, PA 19107 USA
[3] Abington Mem Hosp, Dept Neurol, Abington, PA 19001 USA
[4] Univ Penn, Dept Radiol, Philadelphia, PA 19104 USA
[5] Yale Univ, Sch Med, Dept Neurosurg, New Haven, CT USA
[6] Univ Penn, Dept Neurol, Philadelphia, PA 19104 USA
[7] Univ Penn, Dept Neurosurg, Philadelphia, PA 19104 USA
[8] Westchester Med Ctr, Dept Neurosurg, Valhalla, NY USA
[9] Hosp Univ Penn, Div Neurocrit Care, Dept Neurol, 3 W Gates Pavillion,3400 Spruce St, Philadelphia, PA 19104 USA