1 Department of Neurosurgery, Osaka International Cancer Institute, Osaka, Japan; Department of Neurosurgery, Osaka Neurological Institute, Toyonaka, Japan.
2 Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita, Japan.
3 Department of Neurosurgery, Osaka International Cancer Institute, Osaka, Japan; Department of Neurosurgery, Asahikawa Medical University, Asahikawa, Japan.
4 Department of Neurosurgery, Osaka Neurological Institute, Toyonaka, Japan; Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita, Japan.