[1] Univ Sumatera Utara, Fac Med, Dept Neurosurg, Medan, France
[2] Univ Sumatera Utara, Fac Med, Undergraduate Program Med, Medan, France
[3] Univ Sumatera Utara, Fac Med, Dept Internal Med, Div Infect & Trop Med, Medan, Indonesia
[4] Univ Sumatera Utara, Fac Med, Dept Neurosurg, Jl Dr Mansyur No 5,Padang Bulan, Medan 20155, Sumatera Utara, Indonesia