1. Department of Neurosurgery, Kumamoto University Medical School Osaka, Japan
2. Departments of Neurosurgery, Osaka University Medical School Osaka, Japan
3. Osaka Koseinenkin Hospital Osaka, Japan
4. Kansai Rosai Hospital Osaka, Japan
5. Itami City Hospital Osaka, Japan
6. Toyonaka City Hospital Osaka, Japan
7. Osaka Rosai Hospital Osaka, Japan
8. Osaka National Hospital Osaka, Japan
9. Hospital for Adult Diseases, Osaka, Japan