[1] Macquarie Univ, Fac Med & Hlth Sci, Dept Clin Med, Neurosurg Unit, Sydney, NSW, Australia
[2] Alfred Hosp, Dept Neurosurg, Melbourne, Vic, Australia
[3] Monash Univ, Dept Surg, Melbourne, Vic, Australia
[4] Uniformed Serv Univ Hlth Sci, Dept Surg, F Edward Hebert Sch Med, Bethesda, MD 20814 USA