[1] Univ Tsukuba Hosp, Inst Med, Dept Emergency & Crit Care Med, Tsukuba, Ibaraki, Japan
[2] Univ Tsukuba, Inst Med, Dept Neurosurg, Tsukuba, Ibaraki, Japan
[3] Univ Tsukuba Hosp, Div Stroke & Cerebrovasc Dis, Tsukuba, Ibaraki, Japan
[4] Univ Tsukuba, Inst Med, Dept Orthoped Surg, Tsukuba, Ibaraki, Japan
[5] Univ Tsukuba, Inst Med, Dept Ophthalmol, Tsukuba, Ibaraki, Japan