1. Neurosurgical Department, Medical School Hannover, Hannover, Germany
2. Department of Neurosurgery, Virginia Commonwealth University Medical Center, Richmond, Virginia
3. Division of Neurosurgery, University of California at Los Angeles Medical Center, Los Angeles, California
4. Department of Neurology and Neuroscience, The New York Presbyterian-Weill Cornell Medical College, New York, New York
5. Department of Neurosurgery, Brigham and Women's Hospital, Boston, Massachusetts