1. Department of Neurosurgery The University of Tokyo Bunkyo‐ku Tokyo Japan
2. Department of Neurosurgery Teikyo University Itabashi‐Ku Tokyo Japan
3. Department of Neurosurgery Tokyo Metropolitan Tama Medical Center Fuchu Tokyo Japan
4. Department of Neurosurgery Aizu Chuo Hospital Aizuwakamatsu Fukushima Japan
5. Department of Neuroendovascular Therapy Tokyo Shinjuku Medical Center Shinjuku‐ku Tokyo Japan
6. Department of Neurosurgery Saitama Medical Center Kawagoe Saitama Japan
7. Department of Neurosurgery Showa General Hospital Kodaira Tokyo Japan
8. Department of Neurosurgery NTT Medical Center Tokyo Shinagawa‐ku Tokyo Japan
9. Department of Neurosurgery Teikyo University Chiba Medical Center Ichihara Chiba Japan