Defining combat helmet coverage for protection against explosively propelled fragments

The UK VIRTUS helmet: User feedback from Operation TORAL in Afghanistan

In 2015, the VIRTUS helmet was introduced to UK Armed Forces and will ultimately replace the Mark 7 combat helmet. The VIRTUS helmet has a reduced trimline compared to the Mark 7 helmet and can incorporate attachments such as a visor, mandible guard and nape protection. An anonymous questionnaire was provided to 200 UK Armed Forces personnel deployed to four locations on Operation TORAL in Afghanistan between September and October 2019. This is the first User feedback survey assessing the VIRTUS helmet in an operational environment. Users were measured to ascertain the fit of their helmet and asked to rate perceived helmet mass and comfort using a 5-point Likert scale. Users were also asked whether the VIRTUS helmet was better than previous helmets and about their use of the nape protection. The VIRTUS helmet was perceived to be an improvement over previously issued UK combat helmets in terms of both comfort and mass.

Prehospital aortic blood flow control techniques for non-compressible traumatic hemorrhage

Non-compressible hemorrhage in the junctional areas and torso could be life-threatening and its prehospital control remains extremely challenging. The aim of this review was to compare commonly used techniques for the control of non-compressible hemorrhage in prehospital settings, and thereby provide evidence for further improvements in emergency care of traumatic injuries. Three techniques were reviewed including external aortic compression (EAC), abdominal aortic junctional tourniquet (AAJT), and resuscitative endovascular balloon occlusion of the aorta (REBOA). In prehospital settings, all three techniques have demonstrated clinical effectiveness for the control of severe hemorrhage. EAC is a cost- and equipment-free, easy-to-teach, and immediately available technique. In contrast, AAJT and REBOA are expensive and require detailed instructions or systematic training. Compared with EAC, AAJT and REBOA have greater potentials in the management of traumatic hemorrhage. AAJT can be used not only in the junctional areas but also in pelvic and bilateral lower limb injuries. However, both AAJT and REBOA should be used for a limited time (less than 1 hour) due to possible consequences of ischemia and reperfusion. Compared with EAC and AAJT, REBOA is invasive, requiring femoral arterial access and intravascular guidance and inflation. Mortality from non-compressible hemorrhage could be reduced through the prehospital application of aortic blood flow control techniques. EAC should be considered as the first-line choice for many non-compressible injuries that cannot be managed with conventional junctional tourniquets. In comparison, AAJT or REBOA is recommended for better control of the aorta blood flow in prehospital settings. Although these three techniques each have advantages, their use in trauma is not widespread. Future studies are warranted to provide more data about their safety and efficacy.

Comparing the medical coverage provided by four contemporary military combat helmets against penetrating traumatic brain injury

INTRODUCTION

Modern military combat helmets vary in their shapes and features, but all are designed to protect the head from traumatic brain injury. Recent recommendations for protection against energised projectiles that are characteristic of secondary blast injury is to ensure coverage of both the brain and brainstem.

METHOD

Graphical representations of essential coverage of the head (cerebral hemispheres, cerebellum and brainstem) within an anthropometrically sized model were superimposed over two standard coverage helmets (VIRTUS helmet, Advanced Combat Helmet (ACH)) and two 'high-cut' helmets (a Dismounted Combat Helmet (DCH)) and Combat Vehicle Crewman (CVC) helmet), both of which are designed to be worn with communications devices. Objective shotline coverage from representative directions of projectile travel (-30 to +30 degrees) was determined using the Coverage of Armour Tool (COAT).

RESULTS

VIRTUS and ACH demonstrated similar overall coverage (68.7% and 69.5%, respectively), reflecting their similar shell shapes. ACH has improved coverage from below compared with VIRTUS (23.3% vs 21.7%) due to its decreased standoff from the scalp. The 'high-cut' helmets (DCH and CVC) had reduced overall coverage (57.9% and 52.1%), which was most pronounced from the side.

CONCLUSIONS

Both the VIRTUS and ACH helmets provide excellent overall coverage of the brain and brainstem against ballistic threats. Coverage of both would be improved at the rear by using a nape protector and the front using a visor. This is demonstrated with the analysis of the addition of the nape protector in the VIRTUS system. High-cut helmets provide significantly reduced coverage from the side of the head, as the communication devices they are worn with are not designed to provide protection from ballistic threats. Unless absolutely necessary, it is therefore recommended that high-cut helmets be worn only by those users with defined specific requirements, or where the risk of injury from secondary blast is low.

Protective Headgear Attenuates Forces on the Inner Table and Pressure in the Brain Parenchyma During Blast and Impact: An Experimental Study Using a Simulant-Based Surrogate Model of the Human Head

Military personnel sustain head and brain injuries as a result of ballistic, blast, and blunt impact threats. Combat helmets are meant to protect the heads of these personnel during injury events. Studies show peak kinematics and kinetics are attenuated using protective headgear during impacts; however, there is limited experimental biomechanical literature that examines whether or not helmets mitigate peak mechanics delivered to the head and brain during blast. While the mechanical links between blast and brain injury are not universally agreed upon, one hypothesis is that blast energy can be transmitted through the head and into the brain. These transmissions can lead to rapid skull flexure and elevated pressures in the cranial vault, and, therefore, may be relevant in determining injury likelihood. Therefore, it could be argued that assessing a helmet for the ability to mitigate mechanics may be an appropriate paradigm for assessing the potential protective benefits of helmets against blast. In this work, we use a surrogate model of the head and brain to assess whether or not helmets and eye protection can alter mechanical measures during both head-level face-on blast and high forehead blunt impact events. Measurements near the forehead suggest head protection can attenuate brain parenchyma pressures by as much as 49% during blast and 52% during impact, and forces on the inner table of the skull by as much as 80% during blast and 84% during impact, relative to an unprotected head.

UK military helmet design and test methods

The aim of this paper was to provide the military medical community with an expert summary of military helmets used by HM Armed Forces. The design of military helmets and test methods used to determine the fragmentation and non-ballistic impact protection are discussed. The helmets considered are Parachutist, Combat Vehicle Crewman, Mk6, Mk6A, Mk7 and VIRTUS. The helmets considered provide different levels of fragmentation and non-ballistic impact protection dictated by the materials available at the time of the helmet design and the end-user requirement. The UK Ministry of Defence defines the area of coverage of military helmets by considering external anatomical features to provide protection to the brain and the majority of the brainstem. Established test methods exist to assess the performance of the helmet with respect to the threats; however, these test methods do not typically consider anatomical vulnerability.

A correlation analysis of metacarpal & phalangeal injury pattern from improvised explosive devices amongst armed force personnel

Injuries to the hand during military combat operations, particularly from improvised explosive devices (IEDs) have a significant impact on form, function, mental health and future employment but remain underreported amidst the life and limb-threatening emergencies that garner more attention. An understanding the patterns of hand injuries encountered from IEDs is crucial to optimizing reconstruction and rehabilitation. The aim of this study was to re-evaluate hand injury sustained from IED in order to understand the clinical burden for reconstruction and direct the focus for future hand protection. We identified 484 hand injuries in 380 patients sustained as a result of IEDs among military personnel service in Afghanistan between 2006 and 2013. 53% of all surviving military personnel injured by IEDs sustain injuries to the hand. Analysis of the 103 patients who sustained injury to the metacarpal, phalanges or digital amputation revealed that the middle and ring fingers are most commonly injured. Amputation to the ring finger is strongly associated with injury to the adjacent fingers and amputations to the middle, ring and little fingers concurrently is a commonly observed pattern. The proximal phalanges of the middle and ring fingers had a strong correlation for fracture together. These findings disprove the conventional belief in an ulnar focus of injury and support the quest for a development of combat hand protection that addresses the injury pattern seen.

Optimising ballistic facial coverage from military fragmenting munitions: a consensus statement

VIRTUS is the first United Kingdom (UK) military personal armour system to provide components that are capable of protecting the whole face from low velocity ballistic projectiles. Protection is modular, using a helmet worn with ballistic eyewear, a visor, and a mandibular guard. When all four components are worn together the face is completely covered, but the heat, discomfort, and weight may not be optimal in all types of combat. We organized a Delphi consensus group analysis with 29 military consultant surgeons from the UK, United States, Canada, Australia, and New Zealand to identify a potential hierarchy of functional facial units in order of importance that require protection. We identified the causes of those facial injuries that are hardest to reconstruct, and the most effective combinations of facial protection. Protection is required from both penetrating projectiles and burns. There was strong consensus that blunt injury to the facial skeleton was currently not a military priority. Functional units that should be prioritised are eyes and eyelids, followed consecutively by the nose, lips, and ears. Twenty-nine respondents felt that the visor was more important than the mandibular guard if only one piece was to be worn. Essential cover of the brain and eyes is achieved from all directions using a combination of helmet and visor. Nasal cover currently requires the mandibular guard unless the visor can be modified to cover it as well. Any such prototype would need extensive ergonomics and assessment of integration, as any changes would have to be acceptable to the people who wear them in the long term.

Determining the dimensions of essential medical coverage required by military body armour plates utilising Computed Tomography

INTRODUCTION

Military body armour is designed to prevent the penetration of ballistic projectiles into the most vulnerable structures within the thorax and abdomen. Currently the OSPREY and VIRTUS body armour systems issued to United Kingdom (UK) Armed Forces personnel are provided with a single size front and rear ceramic plate regardless of the individual's body dimensions. Currently limited information exists to determine whether these plates overprotect some members of the military population, and no method exists to accurately size plates to an individual.

METHOD

Computed Tomography (CT) scans of 120 male Caucasian UK Armed Forces personnel were analysed to measure the dimensions of internal thoraco-abdominal anatomical structures that had been defined as requiring essential medical coverage. The boundaries of these structures were related to three potential anthropometric landmarks on the skin surface and statistical analysis was undertaken to validate the results.

RESULTS

The range of heights of each individual used in this study was comparable to previous anthropometric surveys, confirming that a representative sample had been used. The vertical dimension of essential medical coverage demonstrated good correlation to torso height (suprasternal notch to iliac crest) but not to stature (r(2)=0.53 versus 0.04). Horizontal coverage did not correlate to either measure of height. Surface landmarks utilised in this study were proven to be reliable surrogate markers for the boundaries of the underlying anatomical structures potentially requiring essential protection by a plate.

CONCLUSIONS

Providing a range of plate sizes, particularly multiple heights, should optimise the medical coverage and thus effectiveness of body armour for UK Armed Forces personnel. The results of this work provide evidence that a single width of plate if chosen correctly will provide the essential medical coverage for the entire military population, whilst recognising that it still could overprotect the smallest individuals. With regards to anthropometric measurements; it is recommended, based on this work, that torso height is used instead of stature for sizing body armour. Coverage assessments should now be undertaken for side protection as well as for other non-Caucasian populations and females, with anthropometric surveys utilising the three landmarks recommended in this study.

Died of wounds: a mortality review

OBJECTIVES

Combat casualty care is a complex system involving multiple clinicians, medical interventions and casualty transfers. Improving the performance of this system requires examination of potential weaknesses. This study reviewed the cause and timing of death of casualties deemed to have died from their injuries after arriving at a medical treatment facility during the recent conflicts in Iraq and Afghanistan, in order to identify potential areas for improving outcomes.

METHODS

This was a retrospective review of all casualties who reached medical treatment facilities alive, but subsequently died from injuries sustained during combat operations in Afghanistan and Iraq. It included all deaths from start to completion of combat operations. The UK military joint theatre trauma registry was used to identify cases, and further data were collected from clinical notes, postmortem records and coroner's reports.

RESULTS

There were 71 combat-related fatalities who survived to a medical treatment facility; 17 (24%) in Iraq and 54 (76%) in Afghanistan. Thirty eight (54%) died within the first 24 h. Thirty-three (47%) casualties died from isolated head injuries, a further 13 (18%) had unsurvivable head injuries but not in isolation. Haemorrhage following severe lower limb trauma, often in conjunction with abdominal and pelvic injuries, was the cause of a further 15 (21%) deaths.

CONCLUSIONS

Severe head injury was the most common cause of death. Irrespective of available medical treatment, none of this group had salvageable injuries. Future emphasis should be placed in preventative strategies to protect the head against battlefield trauma.

Defining the essential anatomical coverage provided by military body armour against high energy projectiles

INTRODUCTION

Body armour is a type of equipment worn by military personnel that aims to prevent or reduce the damage caused by ballistic projectiles to structures within the thorax and abdomen. Such injuries remain the leading cause of potentially survivable deaths on the modern battlefield. Recent developments in computer modelling in conjunction with a programme to procure the next generation of UK military body armour has provided the impetus to re-evaluate the optimal anatomical coverage provided by military body armour against high energy projectiles.

METHODS

A systematic review of the literature was undertaken to identify those anatomical structures within the thorax and abdomen that if damaged were highly likely to result in death or significant long-term morbidity. These structures were superimposed upon two designs of ceramic plate used within representative body armour systems using a computerised representation of human anatomy.

RESULTS AND CONCLUSIONS

Those structures requiring essential medical coverage by a plate were demonstrated to be the heart, great vessels, liver and spleen. For the 50th centile male anthropometric model used in this study, the front and rear plates from the Enhanced Combat Body Armour system only provide limited coverage, but do fulfil their original requirement. The plates from the current Mark 4a OSPREY system cover all of the structures identified in this study as requiring coverage except for the abdominal sections of the aorta and inferior vena cava. Further work on sizing of plates is recommended due to its potential to optimise essential medical coverage.