1. Department of Orthopaedic Surgery, Shinshu University School of Medicine, Nagano, Japan
2. Department of Orthopaedic Surgery, Marunouchi Hospital, Nagano, Japan
3. Department of Radiology, Shinshu University School of Medicine, Nagano, Japan
4. Department of Medicine, Neurology and Rheumatology, Shinshu University School of Medicine, Nagano, Japan
5. Department of Emergency and Critical Care Medicine, Shinshu University School of Medicine, Nagano, Japan
6. Department of Neurosurgery, Shinshu University School of Medicine, Nagano, Japan
7. Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Nagano, Japan