1. Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
2. Department of Neurosurgery, Hyogo Prefectural Kakogawa Medical Center, Kakogawa, Hyogo, Japan.
3. Department of Emergency and Critical Care Medicine, Hyogo Prefectural Kakogawa Medical Center, Kakogawa, Hyogo, Japan.