1. Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto;
2. Department of Neurosurgery, Tokushima University Graduate School of Medicine, Tokushima;
3. Social Health Welfare Medicine Laboratory, Kyoto;
4. Department of Neurosurgery, Hyogo Prefectural Amagasaki General Medical Center, Amagasaki;
5. Okayama University Graduate School of Medicine, Okayama;
6. Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya;
7. Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata;
8. Department of Neurosurgery, National Cerebral and Cardiovascular Center, Suita;
9. Department of Neurosurgery, Toyama University Graduate School of Medicine, Toyama; and
10. Department of Neurological Cell Therapy, Hokkaido University Graduate School of Medicine, Sapporo, Japan