1. Department of Neurosurgery, Suwa Red Cross Hospital, Suwa, Nagano, Japan
2. Headache Outpatient, Suwa Red Cross Hospital, Suwa, Nagano, Japan
3. Sendai Headache and Neurology Clinic, Sendai, Miyagi, Japan
4. Japan System Techniques Co., Ltd (JAST), Minato-ku, Tokyo, Japan
5. Department of Neurosurgery, Itoigawa General Hospital, Itoigawa, Niigata, Japan
6. Department of Neurology, Itoigawa General Hospital, Itoigawa, Niigata, Japan
7. Department of Neurology, Suwa Red Cross Hospital, Suwa, Nagano, Japan
8. Department of Surgery, Itoigawa General Hospital, Itoigawa, Niigata, Japan