Pelvic injury patterns in blast: Morbidity and mortality.

BACKGROUND: Pelvic trauma has emerged as one of the most severe injuries to be sustained by the victim of a blast insult. The incidence and mortality due to blast-related pelvic trauma is not known, and no data exist to assess the relative risk of clinical or radiological indicators of mortality. METHODS: The UK Joint Theater Trauma Registry was interrogated to identify those sustaining blast-mediated pelvic fractures during the conflicts in Iraq and Afghanistan, from 2003 to 2014, with subsequent computed tomography image analysis. Casualties that sustained more severe injuries remote to the pelvis were excluded. RESULTS: One hundred fifty-nine casualties with a 36% overall mortality rate were identified. Pelvic vascular injury, unstable pelvic fracture patterns, traumatic amputation, and perineal injury were higher in the dismounted fatality group (p < 0.05). All fatalities sustained a pelvic vascular injury. Pelvic vascular injury had the highest relative risk of death for any individual injury and an associated mortality of 56%. Dismounted casualties that sustained unstable pelvic fracture patterns, traumatic amputation, and perineal injury were at three times greater risk (relative risk, 3.00; 95% confidence interval, 1.27-7.09) to have sustained a pelvic vascular injury than those that did not sustain these associated injuries. Opening of the pubic symphysis and at least one sacroiliac joint was significantly associated with pelvic vascular injury (p < 0.001), and the lateral displacement of the sacroiliac joints was identified as a fair predictor of pelvic vascular injury (area under the receiver operating characteristic curve, 0.73). CONCLUSION: Dismounted blast casualties with pelvic fracture are at significant risk of a noncompressible pelvic vascular injury. Initial management of these patients should focus upon controlling noncompressible pelvic bleeding. Clinical and radiological predictors of vascular injury and mortality suggest that mitigation strategies aiming to attenuate lateral displacement of the pelvis following blast are likely to result in fewer fatalities and a reduced injury burden. LEVEL OF EVIDENCE: Prognostic, level III.

Lower Limb Posture Affects the Mechanism of Injury in Under-Body Blast.

Over 80% of wounded Service Members sustain at least one extremity injury. The 'deck-slap' foot, a product of the vehicle's floor rising rapidly when attacked by a mine to injure the limb, has been a signature injury in recent conflicts. Given the frequency and severity of these combat-related extremity injuries, they require the greatest utilisation of resources for treatment, and have caused the greatest number of disabled soldiers during recent conflicts. Most research efforts focus on occupants seated with both tibia-to-femur and tibia-to-foot angles set at 90°; it is unknown whether results obtained from these tests are applicable when alternative seated postures are adopted. To investigate this, lower limbs from anthropometric testing devices (ATDs) and post mortem human subjects (PMHSs) were loaded in three different seated postures using an under-body blast injury simulator. Using metrics that are commonly used for assessing injury, such as the axial force and the revised tibia index, the lower limb of ATDs were found to be insensitive to posture variations while the injuries sustained by the PMHS lower limbs differed in type and severity between postures. This suggests that the mechanism of injury depends on the posture and that this cannot be captured by the current injury criteria. Therefore, great care should be taken when interpreting and extrapolating results, especially in vehicle qualification tests, when postures other than the 90°-90° are of interest.

Characterization of Lower Extremity Blast Injury.

BACKGROUND: Throughout history, traumatic amputation of the lower extremity has been a notable feature of all conflicts involving explosive incidents. Even at the close of the recent conflicts in Afghanistan, there were deaths that were deemed "potentially survivable." The purpose of this study is to characterize lower extremity blast injury and to determine if their amputation levels and associated injury characteristics correlate with a higher risk of mortality. METHODS: the UK Joint Theatre Trauma Registry (JTTR) was interrogated to identify all lower extremity traumatic amputations sustained in both Iraq and Afghanistan between January 2003 and the end of UK operations in August 2014. The mortality rates for each amputation level and associated injuries were determined. FINDINGS: Of the 977 casualties, there were 679 (69.5%) survivors and 298 fatalities (30.5%). There was an increase in survivability from traumatic amputation throughout the conflict, however, traumatic amputations at the close of military activity in 2014 still had a substantial fatality rate of 23%. A more proximal level of amputation, an associated pelvic fracture, and an associated abdominal injury all correlated with an increased mortality rate. DISCUSSION: Several specific injury characteristics associated with traumatic amputation have been identified that are associated with an increased mortality rate to include a more proximal amputation level, pelvic fracture, and abdominal injury. Injury prevention and mitigation measures should be explored to minimize the risk of the associated injuries following blast that portend a higher risk of mortality.

Analysis of isolated transverse process fractures sustained during blast-related events.

BACKGROUND: Personnel have sustained a range of devastating blast injuries during recent conflicts. Previous studies have focused on severe injuries, including to the spine; however, no study has specifically focused on the most common spinal injury-transverse process (TP) fractures. Although their treatment usually requires limited intervention, analysis of TP fractures may help determine injury mechanisms. METHODS: Data were collected from victims with spinal fractures who were injured in improvised explosive device attacks, from the UK's Joint Theatre Trauma Registry. The level and side of each TP fracture were recorded, as well as associated injuries, whether they were mounted or dismounted, and outcome (survivor or fatality). RESULTS: Most (80%) of the TP fractures were lumbar. More bilateral (both left and right fractures at the same level), and L5 TP fractures, were seen in fatalities than survivors. In the mounted group, lumbar TP fractures were statistically significantly associated with fatality, head injury, noncompressible torso hemorrhage, pelvic injury, and other spinal injuries. In the dismounted group, thoracic TP fractures were associated with head, chest wall, and other spinal injuries; and lumbar TP fractures were associated with pelvic and other spinal injuries. CONCLUSIONS: Different injury mechanisms of the TP in the mounted and dismounted groups are likely. Inertial forces acting within the torso due to rapid loading being transferred through the seat, or high intra-abdominal pressures causing the tensile forces acting through the lumbar fascia to avulse the TPs are likely mechanisms in the mounted group. Blunt trauma, violent lateral flexion-extension forces, or rapid flail of the lower extremities causing tension of the psoas muscle, avulsing the TP, are likely causes in the dismounted group. Isolated lumbar TP fractures can be used as markers for more severe injuries, and fatality, in mounted blast casualties. LEVEL OF EVIDENCE: Prognostic and epidemiological, level III.