[1] Beth Israel Deaconess Med Ctr, Dept Surg, Div Neurosurg, Lowry Med Bldg 3B, Boston, MA 02215 USA
[2] Beth Israel Deaconess Med Ctr, Dept Anesthesia Crit Care & Pain Med, Boston, MA 02215 USA
[3] Univ Erlangen Nurnberg, Dept Neurol, Erlangen, Germany
[4] Univ Calif San Diego, Dept Neurosurg, San Diego, CA 92103 USA