1. Department of Neurological Surgery, Nippon Medical School Musashi-Kosugi Hospital, Kawasaki, Kanagawa, Japan;
2. Department of Neurological Surgery for Community Health, Nippon Medical School, Tokyo, Japan;
3. Department of Neurosurgery, Teikyo University School of Medicine, Tokyo, Japan;
4. Department of Judo Physical Therapy, Faculty of Health, Teikyo Heisei University, Tokyo, Japan;
5. Department of Neurosurgery, Japan Labour Health and Welfare Organization, Tokyo Rosai Hospital, Tokyo, Japan