1. Department of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima;
2. Department of Neurological Surgery, Nippon Medical School, Tokyo;
3. Department of Health Informatics, Kyoto University School of Public Health, Kyoto;
4. Graduate School of Medicine and Faculty of Medicine, Kyoto University, Kyoto;
5. Department of Neurosurgery, Kyorin University School of Medicine, Tokyo;
6. Department of Neurological Surgery, Okayama University Graduate School of Medicine, Okayama;
7. Department of Neurosurgery, Shiga University of Medical Science, Shiga;
8. Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto;
9. Department of Advanced Medicine, Yamagata University School of Medicine, Yamagata; and
10. Department of Neurosurgery, Juntendo University, Tokyo, Japan