1 Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.
2 Center for Surgery and Public Health, Harvard Medical School, Harvard T. H. Chan School of Public Health, Department of Surgery, Brigham & Women's Hospital, Boston, Massachusetts.
3 International Center for Spinal Cord Injury, The Kennedy Krieger Institute, The Johns Hopkins University, Baltimore, Maryland.
4 Division of Trauma, Burns, and Critical Care, Department of Surgery, Brigham & Women's Hospital, Boston, Massachusetts.