1. Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon, and Department of Neurological Surgery, Case Western Reserve School of Medicine, Cleveland, Ohio
2. Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon, and Department of Neurosurgery, Dokuz Eylül University, Faculty of Medicine, Izmir, Turkey
3. Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon