1. Department of Neurosurgery (M.D., T.K., M.N.), Graduate School of Medical Sciences, Kanazawa University, Ishikawa, Japan.
2. Department of Neuroanatomy (H.I., M.T.I., O.H.), Graduate School of Medical Sciences, Kanazawa University, Ishikawa, Japan.
3. Department of Neurosurgery, Kanazawa Medical University, Uchinada, Ishikawa, Japan (A.Y.).