1. School of Medicine, Poznan University, 61-701 Poznan, Poland
2. Department of Neurosurgery, University of Virginia Health System, Charlottesville, VA 22908, USA
3. Department of Surgery, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City 807, Taiwan
4. Department of Neurosurgery, Kaohsiung Medical University Hospital, Kaohsiung City 807, Taiwan
5. Department of Neurosurgery, University of Virginia, Charlottesville, VA 22908, USA
6. College of Medicine, Kaohsiung Medical University Hospital, Kaohsiung City 807, Taiwan
7. Department of Occupational Therapy, College of Health Sciences, Kaohsiung Medical University, Kaohsiung City 807, Taiwan