1. Neuroscience Institute, Allegheny General Hospital, Allegheny Health Network, Pittsburgh, PA 15212, USA
2. Department of Orthopedic Surgery and CAPHRI Research School, Maastricht University Medical Center (MUMC+), P.O. Box 616 Maastricht, The Netherlands
3. Department of Orthopaedic Surgery, Allegheny General Hospital, Allegheny Health Network, Pittsburgh, PA 15212, USA
4. Department of Neurosurgery, Allegheny General Hospital, Allegheny Health Network, Pittsburgh, PA 15212, USA