[1] Department of Neurosurgery, University of Texas, Houston Medical School
[2] Dept. of Phys. Med. and Rehab., University of Texas, Houston Medical School
[3] Department of Anesthesia, University of Texas, Houston Medical School
[4] Department of Radiology, University of Texas, Houston Medical School
[5] Department of Surgery, University of Texas, Houston Medical School
[6] Division of Restorative Neurology, Baylor College of Medicine
[7] Department of Neurosurgery, University of Texas, Houston Health Science Center, Houston, TX 77030