Introduction: Outcomes of penetrating brain injuries (PBI) have historically been very poor. In the civilian trauma center setting, mortality has been noted to be greater than 90%. Outcomes of combat-related PBI have been observed to be better, however past studies have not begun analysis at the point of injury and thus don't provide complete insight into the prognosis of this population.

Methods: Retrospective chart review of US active-duty PBI managed at Kandahar Airfield, January 2010-March 2013.

Results: Eighty patients were included. All were male, mean age of 25, and mean Glasgow Coma Score at admission of 8.5. The predominant injury mechanism was blast (72.5%), the remainder suffered gunshots to the head. The most frequent lesions were intraparenchymal hemorrhage (80%), retained fragments (45%) subarachnoid hemorrhage (40%), subdural hematoma (30%), and transtentorial or tonsillar herniation (18.8%). Epidural hematoma, intraventricular hemorrhage, and major cerebrovascular injury (ICA, proximal ACA/MCA/PCA, vein of Galen, or a dural venous sinus) were less common, occurring in less than 10%. The mean GOS at two years was 3.96. Herniation or a cerebrovascular injury correlated with lower two year GOS (1.47, 3.14), as did lower GCS at admission. Comorbid herniation and cerebrovascular injury was 100% mortal. Subdural and epidural hematoma was correlated with higher two year GOS (4.26, 3.8). Thirteen patients expired during resuscitation or had grossly unsalvageable neurological injuries; excluding these, GOS at two years was 4.54.

Conclusions: Contrary to historic understanding of PBI, the prognosis of combat-related PBI is good provided that the patient survives to reach neurosurgical care without frankly non-survivable injury. Even when these are included, GOS at two years still approaches functional independence. Low GCS, herniation, and major cerebrovascular injury appear to confer a worse prognosis; extra-axial lesions that are readily amenable to surgery appear to confer an improved prognosis.

Patient Care: Provide an insight into the probable clinical course of a given combat induced PBI patient to assist in management decision making, and to combat any historically based nihilism that may persist in today's neurosurgical and trauma surgery communities with regards to PBI patients given the excellent (functionally independent) outcomes in this particular cohort.

Learning Objectives: 1. Discuss the outcomes of penetrating brain injury in the military population, and how it differs from civilian casualties. 2. Discuss the clinical presentations that are associated with worse and better outcomes in combat induced PBI. 3. Discuss the reasons that PBI outcomes appear to differ between the civilian and the military populations.

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