[1] Univ Calif San Francisco, Dept Neurol Surg, San Francisco, CA USA
[2] Univ Calif San Francisco, Hosp Epidemiol & Infect Control, San Francisco, CA USA
[3] Univ Calif San Francisco, Hosp Med, San Francisco, CA USA
[4] Barrow Neurol Inst, Dept Neurosurg, Phoenix, AZ 85013 USA
[5] Miami Neurosci Inst, Miami, FL USA