1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
2 Department of Orthopaedics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
3 Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA; Department of Materials Science and Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
4 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
5 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA; Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD, 21201, USA; Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA; Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA. Electronic address: xjia@som.umaryland.edu.