Improvised Explosive Device (IED) attacks on vehicles have been a significant feature of recent conflicts. The Dynamic Response Index (DRI), developed for predicting spinal injury in aircraft ejection, has been adopted for testing vehicles in underbelly blast. Recent papers suggest that DRI is not accurate in blast conditions. We suggest that the distribution of blast and ejection injuries is different. A literature review identified the distribution of spinal fractures in aircraft ejection incidents. A Joint Theatre Trauma Registry search identified victims of mounted IED blast with spinal fractures. The distribution of injuries in the two groups was compared using the Kruskall Wallis test. 329 fractures were identified in ejector seat incidents; 1% cervical, 84% thoracic and 16% lumbar. 245 fractures were identified in victims of mounted blast; 16% cervical, 34% thoracic and 50% lumbar. There was no significant similarity between the two (p=1). There was no statistically significant difference between the distribution of fractures in blast survivors versus fatalities. The difference between blast and ejection injury patterns suggests that injury prediction models for ejection should not be extrapolated to blast mechanisms and that new models need to be developed.
Current military conflicts are characterised by the use of the Improvised Explosive Device (IED). Improvements in personal protection, medical care and evacuation logistics have resulted in increasing numbers of casualties surviving with complex musculoskeletal injuries, often leading to life-long disability. Thus, there exists an urgent requirement to investigate the mechanism of extremity injury caused by these devices in order to develop mitigation strategies. In addition, the wounds of war are no longer restricted to the battlefield; similar injuries can be witnessed in civilian centres following a terrorist attack. Key to mitigating such injuries is the ability to deconstruct the complexities of an explosive event into a controlled, laboratory-based environment. In this study, an anti-vehicle underbelly injury simulator, capable of recreating in the laboratory the impulse from an anti-vehicle (AV) explosion, is presented and characterised. Tests were then conducted to assess the simulator's ability to interact with human cadaveric legs. Two mounting conditions were assessed, simulating a typical seated and standing vehicle passenger using instrumented cadaveric lower limbs. This experimental device, will now allow us (a) to gain comprehensive understanding of the load-transfer mechanisms through the lower limb, (b) to characterise the dissipating capacity of mitigation technologies, and (c) to assess the biofidelity of surrogates.
Counter-insurgency warfare in recent military operations has been epitomised by the use of Improvised Explosive Devices (IED) against coalition troops. Emerging patterns of skeletal fractures, limb amputations and organ injuries, which are caused by these weapons have been described over recent years. This paper describes a retrospective case series of knee dislocations caused by IEDs in recent conflict. Data was obtained about military personnel from 2006 to 2011, who had sustained a knee dislocation while serving in Afghanistan from a prospectively gathered database, the Joint Theatre Trauma Registry (JTTR), maintained by the Academic Department of Military Emergency Medicine, Royal Centre for Defence Medicine. The diagnosis of knee dislocation and its associated skeletal injuries was assessed by review of all relevant plain radiographs, computed tomography scans and magnetic resonance images. The mechanism of injury, incidence of vascular injuries and other skeletal injuries was recorded. During the study period, 23 casualties sustained a knee dislocation caused by an IED. Four casualties had an associated popliteal vascular injury. Eleven injuries were caused in enclosed spaces, and 10 injuries caused by IEDs out in the open. Anterior dislocations were common in the group caused in enclosed spaces. 19/20 patients had at least one other skeletal fracture. Knee dislocations represent an uncommon but important diagnosis in modern warfare. Urgent and careful assessment for any associated vascular injuries or other skeletal injuries may help ensure timely treatment and promote future recovery. Mitigation against knee dislocation may be possible in the enclosed environment because of the predictable pattern of injury.
