[1] Ningxia Med Univ, Gen Hosp, Dept Neurosurg, Yinchuan, Peoples R China
[2] Fourth Mil Med Univ, Xijing Hosp, Dept Neurosurg, Xian 710032, Peoples R China
[3] Ningxia Med Univ, Grad Sch, Yinchuan, Peoples R China
[4] Ningxia Med Univ, Incubat Base Natl Key Lab Cerebrocranial Dis, Yinchuan, Peoples R China