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

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.

Penetrating Neck Injuries Treated at a U.S. Role 3 Medical Treatment Facility in Afghanistan During Operation Resolute Support

Introduction

Military trauma registries can identify broad epidemiological trends from neck wounds but cannot reliably demonstrate temporal casualty from clinical interventions or differentiate penetrating neck injuries (PNI) from those that do not breach platysma.

Materials and Methods

All casualties presenting with a neck wound to a Role 3 Medical Treatment Facility in Afghanistan between January 1, 2016 and September 15, 2019 were retrospectively identified using the Emergency Room database. These were matched to records from the Operating Room database, and computed tomography (CT) scans reviewed to determine damage to the neck region.

Results

During this period, 78 casualties presented to the Emergency Room with a neck wound. Forty-one casualties underwent surgery for a neck wound, all of whom had a CT scan. Of these, 35/41 (85%) were deep to platysma (PNI). Casualties with PNI underwent neck exploration in 71% of casualties (25/35), with 8/25 (32%) having surgical exploration at Role 2 where CT is not present. Exploration was more likely in Zones 1 and 2 (8/10, 80% and 18/22, 82%, respectively) compared to Zone 3 (2/8, 25%).

Conclusion

Hemodynamically unstable patients in Zones 1 and 2 generally underwent surgery before CT, confirming that the low threshold for exploration in such patients remains. Only 25% (2/8) of Zone 3 PNI were explored, with the high negative predictive value of CT angiography providing confidence that it was capable of excluding major injury in the majority of cases. No deaths from PNI that survived to treatment at Role 3 were identified, lending evidence to the current management protocols being utilized in Afghanistan.

Outcomes following penetrating neck injury during the Iraq and Afghanistan conflicts: A comparison of treatment at US and United Kingdom medical treatment facilities

Supplemental digital content is available in the text.

The United States and United Kingdom (UK) had differing approaches to the surgical skill mix within deployed medical treatment facilities (MTFs) in support of the military campaigns in Iraq and Afghanistan.

Defining the medical coverage of ballistic protection to the pelvis and thigh

INTRODUCTION

Pelvis, lower limb and associated genital injury caused by explosive devices was responsible for mortality and considerable long-term morbidity for the UK Armed Forces during combat operations in Afghanistan, resulting in the issue of a pelvic protection system in 2010. The aim of this current research was to determine the medical coverage of the pelvis and thigh and to define the vertical dimensions of ballistic protective material for future pelvic protection (PP).

METHOD

CT scans from 120 male UK Armed Forces personnel were analysed to identify the anthropometric landmarks and vertical boundaries of coverage for the pelvis and thigh. Pelvic height was the vertical distance between the upper border of the iliac crest in the midaxillary plane to the most inferior point of the ischial tuberosity of the pelvis. Upper thigh height was proposed as a 100 mm fixed distance below the ischial tuberosities, enabling a tourniquet to be reproducibly applied. These distances were compared with the ballistic component of the five sizes of tier 1 PP using a paired t-test.

RESULTS

The vertical components of coverage measured using CT scans were all significantly less (p<0.01) compared with all five sizes of tier 1 PP; for example, the ballistic component of the smallest size of tier 1 PP measured 410 mm, which was larger than the 99th percentile male, which measured 346 mm on CT scans.

CONCLUSIONS

While all sizes of tier 1 PP provide coverage to the pelvis and upper thigh structures, there is an opportunity to optimise future PP. For example, comparing the large size of tier 1 PP to the 50th percentile male demonstrated an opportunity to reduce the ballistic protective component by 31%. Reducing the quantity of material used will improve heat dissipation and user comfort and reduce material mass and acquisition costs.

Determining the optimum anatomical coverage of side plates for the VIRTUS body armour and load carriage system

INTRODUCTION

Side plates are worn by UK Armed Forces as part of the VIRTUS body armour and load carriage systems to protect the thorax and abdomen from high-velocity threats. The VIRTUS project has provided the impetus to objectively demonstrate the anatomical coverage provided by side plates.

METHOD

CT scans of 120 male UK Armed Forces personnel were analysed to ascertain the vertical distance between the anterior axillary fold and iliac crest, and horizontal distance between anterior and posterior borders of the liver, delineating the boundaries of essential medical coverage from the side aspects. The percentage of shot-lines intersected by the existing Enhanced Combat Body Armour (ECBA) plates as well as an optimised plate based on the maximum potential dimensions of essential coverage was determined in the Coverage of Armour Tool.

RESULTS

ECBA plates were 101 mm shorter and 4 mm narrower than a plate with dimensions providing essential medical coverage for the 50th percentile subject (157×315 mm). Coverage increased by 35% when using two ECBA plates as side coverage in addition to using the front and rear OSPREY plates in the VIRTUS vest. Two side plates with dimensions providing essential medical coverage for the 50th percentile increased anatomical coverage by a further 16%.

CONCLUSIONS

This analysis has provided strong evidence that ECBA plates are already optimised for side protection, despite not being originally designed for this purpose. They are correctly positioned within the VIRTUS soft body armour vest and the width of the ECBA plate is only 3% less than what would be optimum size for the 50th percentile. Although the height of the plate could be increased to further enhance the anatomical coverage, it is unlikely that this would be acceptable in terms of the human factors, equipment integration or additional mass.

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.

Injury representation against ballistic threats using three novel numerical models

Injury modelling of ballistic threats is a valuable tool for informing policy on personal protective equipment and other injury mitigation methods. Currently, the Ministry of Defence (MoD) and Centre for Protection of National Infrastructure (CPNI) are focusing on the development of three interlinking numerical models, each of a different fidelity, to answer specific questions on current threats. High-fidelity models simulate the physical events most realistically, and will be used in the future to test the medical effectiveness of personal armour systems. They are however generally computationally intensive, slow running and much of the experimental data to base their algorithms on do not yet exist. Medium fidelity models, such as the personnel vulnerability simulation (PVS), generally use algorithms based on physical or engineering estimations of interaction. This enables a reasonable representation of reality and greatly speeds up runtime allowing full assessments of the entire body area to be undertaken. Low-fidelity models such as the human injury predictor (HIP) tool generally use simplistic algorithms to make injury predictions. Individual scenarios can be run very quickly and hence enable statistical casualty assessments of large groups, where significant uncertainty concerning the threat and affected population exist. HIP is used to simulate the blast and penetrative fragmentation effects of a terrorist detonation of an improvised explosive device within crowds of people in metropolitan environments. This paper describes the collaboration between MoD and CPNI using an example of all three fidelities of injury model and to highlight future areas of research that are required.

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.

Induced Pluripotent Stem Cell Therapies for Cervical Spinal Cord Injury

Cervical-level injuries account for the majority of presented spinal cord injuries (SCIs) to date. Despite the increase in survival rates due to emergency medicine improvements, overall quality of life remains poor, with patients facing variable deficits in respiratory and motor function. Therapies aiming to ameliorate symptoms and restore function, even partially, are urgently needed. Current therapeutic avenues in SCI seek to increase regenerative capacities through trophic and immunomodulatory factors, provide scaffolding to bridge the lesion site and promote regeneration of native axons, and to replace SCI-lost neurons and glia via intraspinal transplantation. Induced pluripotent stem cells (iPSCs) are a clinically viable means to accomplish this; they have no major ethical barriers, sources can be patient-matched and collected using non-invasive methods. In addition, the patient’s own cells can be used to establish a starter population capable of producing multiple cell types. To date, there is only a limited pool of research examining iPSC-derived transplants in SCI—even less research that is specific to cervical injury. The purpose of the review herein is to explore both preclinical and clinical recent advances in iPSC therapies with a detailed focus on cervical spinal cord injury.

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.