N. Hunt

Mortality and morbidity from combat neck injury

BACKGROUND: Neck injury represents 11% of battle injuries in UK forces in comparison with 2% to 5% in US forces. The aim of this study was to determine the causes of death and long-term morbidity from combat neck injury in an attempt to recommend new methods of protecting the neck. METHOD: Hospital and postmortem records for all UK servicemen sustaining battle injuries to the neck between January 1, 2006 and December 31, 2010 were analyzed. RESULTS: Neck wounds were found in 152 of 1,528 (10%) of battle injured service personnel. Seventy-nine percent of neck wounds were caused by explosions and were associated with a mortality rate of 41% compared with 78% from gunshot wounds (GSWs). Although current UK OSPREY neck collars can potentially protect zone I from explosive fragments, in the 58% in which the wearing of a neck collar was known, all service personnel chose not to wear the collar. The most common cause of death from explosive fragments was vascular injury (85%). Zone II was the most commonly affected area overall by explosive fragments and had the highest mortality but zone I was associated with the highest morbidity in survivors. CONCLUSIONS: Nape protectors, that cover zone III of the neck posteriorly, would only have potentially prevented 3% of injuries and therefore this study does not support their use. Current UK OSPREY neck collars potentially protect against the majority of explosive fragments to zones I and II and had these collars been worn potentially 16 deaths may have been prevented. Reasons for their lack of uptake by UK servicemen is therefore being evaluated. Surface wound mapping of penetrating explosive fragments in our series has been used to validate the area of coverage required for future designs of neck protection. LEVEL OF EVIDENCE: II.

Surface wound mapping of battlefield occulo-facial injury

INTRODUCTION Accurately determining the entry location of penetrating eye and face wounds and relating that to mortality and long-term morbidity is of vital importance in the design of future personal protective equipment. METHOD Hospital and post mortem records for all UK servicemen sustaining penetrating battle injuries to the face or eye during the period 01 January 2005 to 31 December 2009 were analysed. RESULTS Face and eye injuries were found in 391/1187 (33%) and 113/1187 (10%) of all battle-injured servicemen respectively. 27% of eye wounds from explosions resulted in blindness and a further 17% in significant permanently reduced visual acuity (<6/12). Those servicemen that chose not to wear Combat Eye Protection (CEP) were 36 times more likely to sustain an eye injury from explosive fragmentation than those that did. However only 36% of servicemen chose to wear CEP. 7 deaths could potentially have been prevented had the serviceman chosen to wear their CEP. The lower third of the face was most commonly injured (60%) followed by the upper third (24%). CEP reduced facial injuries as a whole (bone and soft tissue) by 15% (p<0.01). Potentially changing the existing material used for chinstrap and helmet covers to that with ballistic protection would further reduce this incidence by up to 9%. CONCLUSIONS Although the lower third of the face remains poorly protected, the incidence of lower facial wounds could be further reduced by the use of ballistic visors by servicemen in exposed positions in vehicles (which represented 16% of facial injuries). Such a visor could potentially have prevented 17 deaths. A rigid attachment to the front of a ballistic helmet would allow either a visor, a high visibility LED lamp or a night vision goggle to clip in and we believe this capability should be investigated through future human factor trials.

Associated injuries in casualties with traumatic lower extremity amputations caused by improvised explosive devices

Improvised explosive devices (IEDs) pose a significant threat to military personnel, often resulting in lower extremity amputation and pelvic injury. Immediate management is haemorrhage control and debridement, which can involve lengthy surgery. Computed tomography is necessary to delineate the extent of the injury, but it is unclear whether to perform this during or after surgery.

Mandibular fractures in British military personnel secondary to blast trauma sustained in Iraq and Afghanistan

Blast trauma is the primary cause of maxillofacial injury sustained by British service personnel on deployment, and the mandible is the maxillofacial structure most likely to be injured in combat, but there are few reports about the effect of blast trauma on it. The Joint Theatre Trauma Registry identified all mandibular fractures sustained by British servicemen secondary to blast injury between 1 January 2004 and 30 September 2009. These were matched to corresponding hospital notes from the Royal Centre for Defence Medicine (RCDM) for those evacuated servicemen and autopsy records for those who died of wounds. Seventy-four mandibular fractures were identified in 60 servicemen. Twenty-two soldiers were evacuated to the RCDM and the remaining 38 died from wounds. Fractures of the symphysis (39/106, 37%) and body (31/106, 29%) were more common than those of the angle (26/106, 25%) and condyle (10/106, 9%). This pattern of injury differs from that of civilian blunt trauma where the condyle is the site that is injured most often. Those fractures thought to result from the blast wave itself usually caused simple localised fractures, whereas those fractures thought to result from fragments of the blast caused comminution that affected several areas of the mandible. The pattern of fractures in personnel injured while they were inside a vehicle resembled that traditionally seen in blunt trauma, which supports the requirement for mandatory wearing of seat-belts in the rear of vehicles whenever tactically viable. All mandibular fractures in servicemen injured while in the turret of a vehicle had evidence of foreign bodies or radio-opaque fragments as a result of their exposed position. Many of these injuries could therefore be potentially prevented by the adoption of facial protection.

The Mortality Peer Review Panel: a report on the deaths on operations of UK Service personnel 2002–2013

Introduction Review of adverse outcomes is an essential element of healthcare governance. For each operational death, the post-mortem is attended by a member of Academic Department of Military Emergency Medicine and the case is assessed by a Mortality Peer Review Panel comprised of Defence Professors and other clinical and technical experts. Methods A search was conducted of the Joint Theatre Trauma Registry (JTTR) for all UK military death reviews held from January 2002 to November 2013 and the judgement made by the Mortality Peer Review panel. Cases are awarded a ‘salvageability’ rating between S1 (salvageable) and S4 (not salvageable). Cases graded S1–3 are then assessed further for tactical, clinical or equipment factors that affected the outcome. Results There were 621 deaths recorded on the JTTR and 517 (83.3%) were due to hostile action. The Killed in Action to Died of Wounds ratio is 6.28 : 1. Explosive mechanisms of injury were responsible for 55.65% of combat deaths and penetrating mechanisms 28.71%. An average of 10.56 injuries was recorded per casualty and the mean number of body regions affected was 3.34. The Peer Review Panel decided that 91.1% cases were not salvageable (S4); this figure is 93.5% if the deaths due to hostile action are considered separately. Conclusions The severity of modern military trauma is overwhelming in nature and, along with trauma scoring systems, clinical peer review is an essential part of healthcare governance. The process also helps inform and direct research within clinical and force protection fields.

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

INTRODUCTION There 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. METHOD Hospital 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. RESULTS 13/81 (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%. DISCUSSION COAT 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.

Characterisation of explosive fragments injuring the neck

Penetrating explosive fragments are the most common cause of neck injuries sustained by UK service personnel deployed to Afghanistan. Analysis of these fragments will enable future ballistic protective materials to be tested with appropriate projectiles. However, only a small number of fragments excised from the neck have been available for analysis and they are potentially unrepresentative. We analysed computed tomograms (CTs) of 110 consecutive UK soldiers whose necks were wounded by explosive fragments. Fragments were classified according to shape, and their dimensions used to estimate volume and mass. These calculations were then compared with the actual measurements of the excised fragments using a general linear model. The 2 most common shapes were cylinders (52%) and spheres (21%). Known and estimated masses were not significantly different (p=0.64). A fragment-simulating projectile of 0.49 g represented 85% of fragments retained in the neck. CT can accurately delineate the shape and mass of fragments, which increases the number from which the most appropriate simulated projectile can be designed. We think that this methodology should be applied to fragments retained in other parts of the body to enable broader recommendations to be made regarding the testing of ballistic materials used to protect service personnel.

Using computerised surface wound mapping to compare the potential medical effectiveness of Enhanced Protection Under Body Armour Combat Shirt collar designs

Introduction Protecting the neck from explosively propelled fragments has traditionally been achieved through a collar attached to the ballistic vest. An Enhanced Protection Under Body Armour Combat Shirt (EP-UBACS) collar has been identified as an additional method of providing neck protection but limited evidence as to its potential medical effectiveness exists to justify its procurement. Method Entry wound locations and resultant medical outcomes were determined using Abbreviated Injury Scale (AIS) for all fragmentation neck wounds sustained by UK soldiers between 01 January 2010 and 31 December 2011. Data were prospectively entered into a novel computerised tool base and comparisons made between three EP-UBACS neck collar designs in terms of predicted reduction in AIS scores. Results All collars reduced AIS scores, with the greatest reduction provided by designs incorporating increased standoff from the neck and an additional semi-circle of ballistic material underneath the collar at the front and back. Discussion This technique confirms that reinforcing the neck collar of an EP-UBACS would be expected to reduce injury severity from neck wounds. However, without knowledge of entry wound locations for injuries to other body areas as well as the use of AIS scores without clinical or pathological verification its further use in the future may be limited. The ability to overlay any armour design onto a standardised human was potentially the most useful part of this tool and we would recommend developing this technique using underlying anatomical structures and not just the skin surface.

Clinical and post mortem analysis of combat neck injury used to validate a novel Coverage of Armour Tool

Introduction: The Ministry of Defence requires an objective method of comparing between body armour designs for potential future conflicts post Afghanistan. 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. Method: Hospital 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 were analysed to determine which anatomical structures were responsible for death or functional disability at one year post injury. These structures were compared to those predicted by Abbreviated Injury Scores (AIS) and Functional Capacity Index (FCI) scores. Results: 13/81 survivors demonstrated complications at one year, most commonly upper limb weakness from brachial plexus injury or a weak voice from laryngeal trauma. 14/94 soldiers died from a neck wound alone, primarily from carotid artery damage, spinal cord transection and rupture of the larynx. Discussion: The use of AIS scores 5 + 6 in combination with FCI scores 1 + 2 was demonstrated to potentially reflect true morbidity and to a lesser degree mortality and we would recommend their use when choosing representative anatomical structures for the remaining body where the clinical data determined in this paper is not yet available. COAT should be developed to enable weapon and tissue specific information to be modelled such as the incorporation of a permanent wound tract.

Computed Tomography Can Improve the Selection of Fragment Simulating Projectiles From Which to Test Future Body Armor Materials

INTRODUCTION Ballistic protective materials used in body armor are tested with fragment simulating projectiles (FSPs). The type of FSP used has historically been made by choosing fragments representative of those produced by controlled explosions, which may not be representative of those fragments actually injuring soldiers. METHOD 75 cylindrical FSPs of three different sizes were fired into six euthanized pigs, imaged using computed tomography (CT) and the wound tracks dissected. Skin entry wound locations, as determined by surface-shaded CT, were compared to clinical photographs. FSP dimensions and depth of penetration derived from CT were compared to surgical dissection using a Mann-Whitney U test. RESULTS Skin entry wound locations derived from CT were identical to that seen clinically. FSP dimensions were consistently 15% to 19% larger than the true measurements, reflecting the magnifying effect associated with metallic artifact. No statistical difference (p = 0.26) was found between depth of penetration measured radiologically compared to dissection when a projectile did not hit bone but there was a statistical difference when bone was hit (p < 0.05). CONCLUSIONS CT has the potential to accurately ascertain values required to improve the selection of representative FSPs from which future ballistic protective materials are tested.