[1] George Washington Univ, Sch Med & Hlth Sci, Washington, DC USA
[2] Virginia Commonwealth Univ, Sch Med, Richmond, VA USA
[3] Brown Univ, Warren Alpert Med Sch, Providence, RI USA
[4] Univ Calif Los Angeles, David Geffen Sch Med, Los Angeles, CA USA
[5] Northwestern Univ, Feinberg Sch Med, Chicago, IL USA
[6] Univ Montreal, Ste Justine Univ Hosp, Dept Surg, Div Neurosurg, Quebec City, PQ, Canada
[7] Univ Montreal, Dept Neurosci, Quebec City, PQ, Canada
[8] Univ Montreal, Ste Justine Hosp, Div Neurosurg, Quebec City, PQ, Canada
[9] Univ Calif Los Angeles UCLA, Dept Neurosurg & Pediat, 300 Stein Plaza Driveway,Suite 525, Los Angeles, CA 90095 USA