1. Department of Neurosurgery, Hyogo Prefectural Awaji Hospital, Sumoto, and Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Japan
2. Department of Neurosurgery, Hyogo Prefectural Awaji Hospital, Sumoto, Japan
3. Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Japan