1. University of California, San Francisco, Brain & Spinal Injury Center, Department of Neurological Surgery, San Francisco General Hospital, Bldg 1, Room 101, 1001 Potrero Avenue, San Francisco, CA 94110-0899, USA.
2. University of California, San Francisco, Department of Physical Therapy & Rehabilitation Sciences, Bldg 1, Room 242 San Francisco General Hospital, Bldg 1, Room 101, 1001 Potrero Avenue, San Francisco, CA 94110-0899, USA.
3. Skubiszewski Medical University Lublin, Department of Neurological Surgery F. Skubiszewski Medical University 8 Jaczewskiego St, Lublin, Poland.
4. University of California, San Francisco, Department of Neurological Surgery, 505 Parnassus Ave, Room M779, San Francisco, CA 94143-0112, USA.
5. University of California, San Francisco, Brain & Spinal Injury Center, Department of Neurological Surgery, San Francisco General Hospital, Bldg 1, Room 101, 1001 Potrero Avenue, San Francisco, CA 94110-0899, USA.