1. Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, Kagoshima;
2. Department of Neurosurgery, Shiroyama Hospital, Habikino;
3. Department of Neurosurgery, Kouseikai Takai Hospital, Tenri;
4. Department of Neurosurgery, Osaka City General Hospital, Osaka;
5. Jiro Suzuki Memorial Gamma House, Furukawa Seiryo Hospital, Osaki;
6. Yokohama CyberKnife Center, Shinryoku Neourosurgical Clinic, Yokohama;
7. Department of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima;
8. Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto; and
9. Tokyo Rosai Hospital, Tokyo, Japan