1. Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA;
2. Cleveland Clinic Center for Spine Health, Neurologic Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA;
3. Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio, USA;
4. Case Western Reserve University School of Medicine, Cleveland, Ohio, USA;
5. Department of Neurosurgery, New York University, New York, New York, USA;
6. Department of Neurosurgery, Memorial Sloan Kettering, New York, New York, USA;
7. Department of Neurosurgery, Oregon Health & Science University, Portland, Oregon, USA