1. Department of Neuropathology Research Institute for Brain and Blood Vessels, Akita Cerebrospinal and Cardiovascular Center Akita Japan
2. Akita University School of Medicine Akita Japan
3. Department of Neurosurgery TMG Asaka Medical Center Saitama Japan
4. Department of Neurosurgery Saiseikai Kurihashi Hospital Saitama Japan
5. Department of Neurosurgery Tokyo Women's Medical University, Medical Center East Tokyo Japan