1. Department of Neurosurgery, Graduate School of Medicine, Tohoku University, Sendai 980-8572, Japan
2. Department of Neurosurgery, Tohoku Medical and Pharmaceutical University, Sendai 981-8558, Japan
3. Department of Neurosurgery, Saitama Red Cross Hospital, Saitama 330-8553, Japan
4. Department of Neurosurgical Engineering and Translational Neuroscience, Graduate School of Medicine, Tohoku University, Sendai 980-8576, Japan
5. Department of Neurosurgical Engineering and Translational Neuroscience, Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8572, Japan