1 Department of Neurosurgery, Musashino General Hospital, Saitama, Japan; Department of Neurosurgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan.
2 Department of Neurosurgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan.
3 Department of Neurosurgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan. Electronic address: sooya-tky@umin.ac.jp.