1. Department of Neurosurgery, Social Insurance Tagawa Hospital, Kamihonmachi, Tagawa,
2. Department of Neurosurgery, Uchikado Neuro-Spine Clinic, Hakata-Ku Naka, Fukuoka,
3. Department of Neurosurgery, Kurume University School of Medicine, Asahi-Machi, Kurume, Japan.