[1] Univ Southern Calif, Dept Neurosurg, Los Angeles, CA 90007 USA
[2] Prince Wales Private Hosp, Ctr Minimally Invas Neurosurg, Sydney, NSW, Australia
[3] Cingulum Hlth, Sydney, NSW, Australia
[4] Univ Oklahoma Hlth Sci Ctr, Dept Neurosurg, Oklahoma City, OK 73104 USA
[5] Rutgers Robert Wood Johnson Sch Med, New Brunswick, NJ 08903 USA