1. Department of Neurosurgery, Neurological Institute, Taichung Veterans General Hospital, Taichung 407, Taiwan
2. Department of Orthopaedics, Tzuchi General Hospital, Taichung 427, Taiwan
3. Department of Radiology, Taichung Veterans General Hospital, Taichung 407, Taiwan
4. Functional Neurosurgery Division, Neurological Institute, Taichung Veterans General Hospital, Taichung 407, Taiwan
5. Department of Rehabilitation, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli 356, Taiwan
6. Department of Orthopedics, Taichung Veterans General Hospital, Taichung 407, Taiwan