1. Department of Neurosurgery, Hyogo Medical University, Nishinomiya, Japan;
2. Department of Neurosurgery, Division of Neuroendovascular Surgery, Medical University of South Carolina, Charleston, South Carolina, USA;
3. Department of Clinical Epidemiology, Hyogo Medical University, Nishinomiya, Japan;
4. Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA;
5. Department of Neurosurgery, Thomas Jefferson University Hospitals, Philadelphia, Pennsylvania, USA;
6. Department of Neurosurgery, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA;
7. Department of Neurosurgery, University of Washington, Seattle, Washington, USA;
8. Department of Neurosurgery and Neurointerventional Radiology, Louisiana State University, Shreveport, Louisiana, USA;
9. Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA;
10. Department of Neurosurgery, University of Texas Medical Branch—Galveston, Galveston, Texas, USA;
11. Department of Neuroradiology, Washington Regional J.B. Hunt Transport Services Neuroscience Institute, Fayetteville, Arkansas, USA