1 Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100730, China.
2 Department of Neurosurgery, the First Affiliated Hospital, Harbin Medical University, Harbin, 150001, China.
3 Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100730, China. wrzpumch@163.com.