1. Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo, Japan.
2. Department of Orthopedic Surgery, Saiseikai Yokohama-shi Tobu Hospital, Kanagawa, Japan.
3. Department of Orthopedic Surgery, Hokkaido Spinal Cord Injury Center, Hokkaido, Japan.
4. Department of Orthopedic Surgery, Spinal Injuries Center, Fukuoka, Japan.
5. Department of Orthopedic Surgery, Murayama Medical Center, National Hospital Organization, Tokyo, Japan.
6. Faculty of Data Science, Yokohama City University School of Data Science, Kanagawaken, Japan.
7. Biostatistics, Clinical and Translational Research Center, and Keio University School of Medicine, Tokyo, Japan.
8. Kringle Pharma, Inc., Osaka, Japan.
9. Department of Physiology, Keio University School of Medicine, Tokyo, Japan.