1. Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA;
2. Department of Neurological Surgery, Albany Medical College, Albany, New York, USA;
3. Albany Medical College, Albany, New York, USA;
4. Department of Neurological Surgery, Jacobs School of Medicine and Biomedical Sciences at University at Buffalo, New York, New York, USA;
5. University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA