1. Department of Neurosurgery, MedStar Georgetown University Hospital, Washington, District of Columbia, USA
2. Georgetown University School of Medicine, Washington, District of Columbia, USA
3. Department of Neurosurgery, MedStar Washington Hospital Center, Washington, District of Columbia, USA
4. Department of Critical Care Medicine, MedStar Washington Hospital Center, Washington, District of Columbia, USA
5. Department of Neurology, Georgetown University Medical Center, Washington, District of Columbia, USA