[1] New York Presbyterian Columbia, Dept Neurosurg, New York, NY USA
[2] Duke Univ, Dept Neurosurg, Durham, NC USA
[3] Washington Univ, Dept Neurosurg, Sch Med, St Louis, MO USA
[4] Univ Calgary, Dept Neurosurg, Calgary, AB, Canada
[5] Univ Southern Calif, Dept Neurosurg, Los Angeles, CA USA
[6] Washington Univ, Sch Med, Dept Pediat Anat & Neurobiol, St Louis, MO USA