1. Department of Natural Medical Sciences, College of Health Science, Chosun University, Gwangju, Korea.
2. Department of Neurosurgery, Sun Han Hospital, Gwangju, Korea.
3. Department of Thoracic and Cardiovascular Surgery, College of Medicine, Chosun University, Gwangju, Korea.
4. Department of Neurosurgery, College of Medicine, Chosun University, Gwangju, Korea.