J C Clasper

Improvised Explosive Devices: Pathophysiology, Injury Profiles and Current Medical Management

The Improvised Explosive Device (IED), in all its forms, has become the most significant threat to troops operating in Afghanistan and Iraq. These devices range fromrudimentary homemade explosives to sophisticated weapon systems containing high-grade explosives. Within this broad definition they may be classified as Roadside explosives and blast mines, Explosive Formed Pojectile (EFP) devices and Suicide bombings. Each of these groups cause injury through a number of different mechanisms and can result in vastly different injury profiles. The “Global War on Terror” has meant that incidents which were previously exclusively seen in conflict areas, can occur anywhere, and clinicians who are involved in emergency trauma caremay be required tomanage casualties fromsimilar terrorist attacks. An understanding of the types of devices and their pathophysiological effects is necessary to allow proper planning of mass casualty events and to allow appropriate management of the complex poly-trauma casualties they invariably cause. The aim of this review article is to firstly describe the physics and injury profile from these different devices and secondly to present the current clinical evidence that underpins their medical management.

Predicting the need for early amputation in ballistic mangled extremity injuries.

BACKGROUNDnDespite modern advances, amputation is still a commonly performed operation in war. It is often difficult to decide whether to amputate after high-energy trauma to the lower extremity. To help guide this assessment, scoring systems have been developed with amputation threshold values. These studies were all conducted on a civilian population, encompassing a wide range of ages and methods of injury. The evidence for their sensitivity and specificity is inconclusive. The aim of this study was to assess the validity of the mangled extremity severity score (MESS), the only verified score, in a population of UK military patients with ballistic mangled extremity injuries.nnnMETHODSnWe identified from the prospectively kept Joint Theater Trauma Registry all patients who had sustained ballistic lower limb open fractures during the recent conflicts in Iraq and Afghanistan (May 2003-April 2008). Demographics were assessed using both the trauma audit and the hospital notes. Patients were retrospectively evaluated with the MESS system for lower extremity trauma. Those that required an amputation were compared with those that had successful limb salvage.nnnRESULTSnSeventy-seven military patients with 86 limbs who had ballistic mangled extremity injuries were identified, 22 of whom required amputation. The MESS did not help to decide whether or not an amputation was appropriate and in particular, the age was not relevant. A skeletal score of 4, while being associated with a higher amputation rate, was not predictive of its need. Most amputations were performed when an ischemic limb was present, and the general condition of the casualty precluded the lengthy reconstruction required for salvage.nnnCONCLUSIONSnThe management of ballistic extremity injuries in military patients should be considered separate to that of civilians with high-energy trauma extremity injuries. The authors have identified important factors in the management, in particular the need for early amputation, of the military mangled extremity.

Blast mines: physics, injury mechanisms and vehicle protection

Since World War II, more vehicles have been lost to land mines than all other threats combined. Anti-vehicular (AV) mines are capable of disabling a heavy vehicle, or completely destroying a lighter vehicle. The most common form of AV mine is the blast mine, which uses a large amount of explosive to directly damage the target. In a conventional military setting, landmines are used as a defensive force-multiplier and to restrict the movements of the opposing force. They are relatively cheap to purchase and easy to acquire, hence landmines are also potent weapons in the insurgents’ armamentarium. The stand-off nature of its design has allowed insurgents to cause significant injuries to security forces in current conflicts with little personal risk. As a result, AV mines and improvised explosive devices (IEDs) have become the most common cause of death and injury to Coalition and local security forces operating in Iraq and Afghanistan. Detonation of an AV mine causes an explosive, exothermic reaction which results in the formation of a shockwave followed by a rapid expansion of gases. The shockwave is mainly reflected by the soil/air interface and fractures the soil cap over the mine. The detonation products then vent through the voids in the soil, resulting in a hollow inverse cone which consists of the detonation gases surrounded by the soil ejecta. It is the combination of the detonation products and soil ejecta that interact with the target vehicle and cause injury to the vehicle occupants. A number of different strategies are required to mitigate the blast effects of an explosion. Primary blast effects can be reduced by increasing the standoff distance between the seat of the explosion and the crew compartment. Enhancement of armour on the base of the vehicle, as well as improvements in personal protection can prevent penetration of fragments. Mitigating tertiary effects can be achieved by altering the vehicle geometry and structure, increasing vehicle mass, as well as developing new strategies to reduce the transfer of the impulse through the vehicle to the occupants. Protection from thermal injury can be provided by incorporating fire resistant materials into the vehicle and in personal clothing. The challenge for the vehicle designer is the incorporation of these protective measures within an operationally effective platform.

40 years of terrorist bombings – A meta-analysis of the casualty and injury profile

INTRODUCTIONnTerrorists have used the explosive device successfully globally, with their effects extending beyond the resulting injuries. Suicide bombings, in particular, are being increasingly deployed due to the devastating effect of a combination of high lethality and target accuracy. The aim of this study was to identify trends and analyse the demographics and casualty figures of terrorist bombings worldwide.nnnMETHODSnAnalysis of the Global Terrorism Database (GTD) and a PubMed/Embase literature search (keywords terrorist, and/or suicide, and/or bombing) from 1970 to 2014 was performed.nnnRESULTSn58,095 terrorist explosions worldwide were identified in the GTD. 5.08% were suicide bombings. Incidents per year are increasing (P<0.01). Mean casualty statistics per incidents was 1.14 deaths and 3.45 wounded from non-suicide incidents, and 10.16 and 24.16 from suicide bombings (p<0.05). The kill:wounded ratio was statistically higher in suicide attacks than non-suicide attacks, 1:1.3 and 1:1.24 respectively (p<0.05). The Middle East witnessed the most incidents (26.9%), with Europe (13.2%) ranked 4th. The literature search identified 41 publications reporting 167 incidents of which 3.9% detailed building collapse (BC), 60.8% confined space (CS), 23.5% open space (OS) and 11.8% semi-confined space (SC) attacks. 60.4% reported on suicide terrorist attacks. Overall 32 deaths and 180 injuries per incident were seen, however significantly more deaths occurred in explosions associated with a BC. Comparing OS and CS no difference in the deaths per incident was seen, 14.2(SD±17.828) and 15.63 (SD±10.071) respectively. However OS explosions resulted in significantly more injuries, 192.7 (SD±141.147), compared to CS, 79.20 (SD±59.8). Extremity related wounds were the commonest injuries seen (32%).nnnDISCUSSION/CONCLUSIONnTerrorist bombings continue to be a threat and are increasing particularly in the Middle East. Initial reports, generated immediately at the scene by experienced coordination, on the type of detonation (suicide versus non-suicide), the environment of detonation (confined, open, building collapse) and the number of fatalities, and utilising the Kill:Wounded ratios found in this meta-analysis, can be used to predict the number of casualties and their likely injury profile of survivors to guide the immediate response by the medical services and the workload in the coming days.

The changing pattern of amputations

Introduction Conflict in the Middle East over the past 10u2005years has seen a change in warfare tactics from the use of ballistic missiles to blast weapons, which has resulted in a well-documented change in wounding patterns. Due to the severity of these injuries, there have been large numbers of amputations, both as life and limb saving procedures. The purpose of this paper is to retrospectively review all UK service personnel who have undergone limb amputation in the last 8u2005years of conflict and compare those from the early years with the more recent. Methods All UK service personnel scoring more than 1 on the extremity score of the Abbreviated Injury Score were identified from the UK Joint Theatre Trauma Registry and separated into two temporal cohorts (August 2003–February 2008 and August 2008–July 2010). Intheatre medical facility and Role 4 hospital notes from the Queen Elizabeth Hospital Birmingham were examined for details of mechanisms of injury, number of limbs injured, associated injuries, method of amputation, microbiology of contaminating organisms and outcome. Results There were significant differences in the nature of the amputations, the number of multiple amputations and soft tissue perineal wounds, as well as a significantly higher Injury Severity Score in the later time period. There were also significant differences in the surgical techniques, with more guillotine amputations in the early group, and mechanism of injury, with more blast injuries in the late group. Conclusions This study has confirmed the clinical impression that there has been a significant change in the limb trauma from the Iraq conflict to Afghanistan. These injury patterns have significantly different logistic implications and this must be considered when planning the required medical assets in future conflicts.

Clinical and post mortem analysis of combat neck injury used to inform a novel coverage of armour tool

INTRODUCTIONnThere is a requirement in the Ministry of Defence for an objective method of comparing the area of coverage of different body armour designs for future applications. Existing comparisons derived from surface wound mapping are limited in that they can only demonstrate the skin entry wound location. The Coverage of Armour Tool (COAT) is a novel three-dimensional model capable of comparing the coverage provided by body armour designs, but limited information exists as to which anatomical structures require inclusion. The aim of this study was to assess the utility of COAT, in the assessment of neck protection, using clinically relevant injury data.nnnMETHODnHospital notes and post mortem records of all UK soldiers injured by an explosive fragment to the neck between 01 Jan 2006 and 31 December 2012 from Iraq and Afghanistan were analysed to determine which anatomical structures were responsible for death or functional disability at one year post injury. Using COAT a comparison of three ballistic neck collar designs was undertaken with reference to the percentage of these anatomical structures left exposed.nnnRESULTSn13/81 (16%) survivors demonstrated complications at one year, most commonly upper limb weakness from brachial plexus injury or a weak voice from laryngeal trauma. In 14/94 (15%) soldiers the neck wound was believed to have been the sole cause of death, primarily from carotid artery damage, spinal cord transection or rupture of the larynx. COAT objectively demonstrated that despite the larger OSPREY collar having almost double the surface area than the two-piece prototype collar, the percentage area of vulnerable cervical structures left exposed only reduced from 16.3% to 14.4%.nnnDISCUSSIONnCOAT demonstrated its ability to objectively quantify the potential effectiveness of different body armour designs in providing coverage of vulnerable anatomical structures from different shot line orientations. To improve its utility, it is recommended that COAT be further developed to enable weapon and tissue specific information to be modelled, and that clinically significant injuries to other body regions are also incorporated.

Mediastinal injury is the strongest predictor of mortality in mounted blast amongst UK deployed forces

BACKGROUNDnBlast injury has been the most common cause of morbidity and mortality encountered by UK forces during recent conflicts. Injuries sustained by blast are categorised by the injuring component of the explosion and depend upon physical surroundings. Previous work has established that head injuries and intra cavity haemorrhage are the major causes of death following exposure to under body (mounted) blast but has yet to explore the precise nature of these torso injuries nor the effect of particular injuries upon survival. This study examines the patterns of torso injury within the mounted blast environment in order to understand the effect of these injuries upon survivability.nnnMETHODSnThis retrospective study examined the UK Joint Theatre Trauma Registry to determine precise injury patterns of mounted blast casualties within a 13year period of UK military deployments. Survival rates of individual injuries were compared and a multivariable logistic regression model was developed in order to assess the effect that each injury had upon likelihood of death.nnnRESULTSn426 mounted casualties were reviewed of whom 129 did not survive. Median NISS and ISS for non-survivors was found to be 75. Torso injuries were significantly more common amongst non-survivors than survivors and high case fatality rates were associated with all haemorrhagic torso injuries. Multivariable analysis shows that mediastinal injuries have the largest odds ratio for mortality (20.4) followed by lung laceration and head injury.nnnCONCLUSIONSnNon-compressible torso haemorrhage is associated with mortality amongst mounted blast. Of this group, mediastinal injury is the strongest predictor of death and could be considered as a surrogate marker of lethality. Future work to link blast loading characteristics with specific injury patterns will inform the design of mitigating strategies in order to improve survivability of underbody blast.

Trauma-related amputations in war and at a civilian major trauma centre—comparison of care, outcome and the challenges ahead

The Afghanistan conflict has resulted in a large number of service personnel sustaining amputations. Whilst obvious differences exist between military and civilian trauma-related amputations both settings result in life changing injuries. Comparisons offer the potential of advancement and protection of the knowledge gained during the last 12 years. This paper compares the military and civilian trauma-related amputee cohorts demographics, management and rehabilitation outcomes measures. The UK military Joint Theatre Trauma Registry and a civilian major trauma centre database of trauma-related amputees were analysed. 255 military and 24 civilian amputees were identified. A significant difference (p>0.05) was seen in median age (24, range 18-43, vs. 48, range 24-87 years), mean number of amputations per casualty (1.6±SD 0.678 vs. 1±SD 0.0), mean ISS (22±SD 12.8 vs. 14.7±SD 15.7) and gender (99% males vs. 78%). Rehabilitation outcome measures recorded included the Special Interest Group in Amputee Medicine score where the military group demonstrated significantly better scores (91% Grade E+ compared to 19%). Differences in patients underlying physiology and psychology, the military trauma system and a huge sustained investment in rehabilitation are all contributing factors for these differing outcomes. However the authors also believe that the use of a consultant-led MDT and central rehabilitation have benefited the military cohort in the acute rehabilitation stage and is reflected in the good short-term outcomes.

Experimental platforms to study blast injury

Injuries sustained due to attacks from explosive weapons are multiple in number, complex in nature, and not well characterised. Blast may cause damage to the human body by the direct effect of overpressure, penetration by highly energised fragments, and blunt trauma by violent displacements of the body. The ability to reproduce the injuries of such insults in a well-controlled fashion is essential in order to understand fully the unique mechanism by which they occur, and design better treatment and protection strategies to alleviate the resulting poor long-term outcomes. This paper reports a range of experimental platforms that have been developed for different blast injury models, their working mechanism, and main applications. These platforms include the shock tube, split-Hopkinson bars, the gas gun, drop towers and bespoke underbody blast simulators.