1. Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan;
2. Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan;
3. Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan;
4. Institute of Statistics, National Yang Ming Chiao Tung University, Hsin-Chu, Taiwan;
5. Department of Neurology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan; and
6. Department of Anatomy and Cell Biology, National Taiwan University College of Medicine, Taipei, Taiwan