The combat burst fracture study—results of a cohort analysis of the most prevalent combat specific mechanism of major thoracolumbar spinal injury

Introduction: In 2009–2010, military physicians hypothesized that a new pattern of spinal injury had emerged, resulting from improvised explosive device assault on up-armored vehicles, associated with a high rate of point of first contact fracture and neurological injury—the combat burst fracture. We sought to determine the incidence of all thoracolumbar (TL) burst fractures and combat burst fractures in 2009–2010 as compared to two antecedent years.

Methods: A screening process identified all individuals who sustained TL burst fractures in the time-period studied. Demographics, injury-specific characteristics, mechanism of injury, surgical interventions and early complications were recorded. Incidence rates were calculated for the three time periods using total deployed troop-strength and number of LRMC combat admissions as denominators. The incidences of TL burst fractures within each year group and by mechanism were compared, and clinical characteristics and process of care were described.

Results: Between 2007–2010, 65 individuals sustained a TL burst fracture. The incidence of these injuries in 2009–2010 was 2.1 per 10,000 soldier-years and accounted for 3.0 % of LRMC combat-casualty admissions, a significant increase from 0.6 % and 1.1 % in 2007–2008 and 2008–2009, respectively (p ≤ 0.001). In 2009–2010, US soldiers were 3.4–4.6 times more likely to sustain a TL burst fracture compared to 2008–2009 and 2007–2008 (p < 0.001), and the most common mechanism of injury was IED vs. vehicle (65 %)—the combat burst fracture mechanism. Neurological deficits were present in 43 % of TL burst fractures and 1/3 were complete injuries. Spinal fixation was performed in 68 % overall and 74 % of combat burst fractures.

Conclusions: There was a 3.4- to 4.6-fold increase in TL burst fractures in 2009–2010 compared to antecedent years. The primary driver of this phenomenon was the marked increased in combat burst fractures. Mitigating/preventing the mechanism behind this major spinal injury is a key research initiative for the US military.

Level of Evidence III (Case–control).