Injury-Specific Correlates of Combat-Related Traumatic Brain Injury in Operation Iraqi Freedom

Background: The prevalence of traumatic brain injury (TBI) has increased during the wars in Iraq and Afghanistan compared with 20th century military conflicts. The aim of this study was to elucidate injury-specific correlates of combat-related TBI that have yet to be clearly defined. Participants: Predominately Marine US service members who sustained brain injuries in Iraq between March 2004 and April 2008 identified from clinical records completed in the theater of combat operations (n = 2074). Main Outcome Measures: Severity of TBI was classified as mild, moderate, or severe. Injury-specific factors, such as injury mechanism and type, were abstracted from the clinical records and were compared with severity of TBI. Results: Of all TBIs observed in the sample, 89% were mild. Higher severity of TBI was associated with an increased likelihood of sustaining the injury by gunshot and a lower likelihood of helmet use. Improvised explosive devices were associated with a preponderance of mild TBIs, and frequency of injuries in locations in addition to the head was highest among those with moderate and severe TBIs. Concomitant injuries to the spine/back were associated with blast injury mechanisms. Conclusions: Most incidents of TBI occurring during Operation Iraqi Freedom are mild in severity and a result of blast mechanisms. Multiple injuries were common, particularly as severity of TBI increased. Further research is needed to determine effects of combat-related TBI on rehabilitative and adverse health outcomes.