1. Harvard Medical School, Boston, Massachusetts, USA;
2. Department of Neurological Surgery, Massachusetts General Hospital, Boston, Massachusetts, USA;
3. Department of Neurological Surgery, University of Miami, Miami, Florida, USA;
4. Department of Neurological Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA;
5. Department of Neurological Surgery, Baylor College of Medicine, Houston, Texas, USA