1. Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA;
2. Ponce Health Sciences University, Ponce, Puerto Rico;
3. The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA;
4. Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA;
5. Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, USA