Minimum depths to essential structures in a UK military population using computed tomography: application to stab-resistant body armour.

INTRODUCTION: Edged weapons are a known domestic threat to the police forces of the UK. This threat is mitigated by wearing stab-resistant body armour that is either worn overtly or covertly depending on role. Although the UK military have traditionally focused their body armour design upon ballistic and fragmentation threats, future roles may require protection against an edged weapon threat. Since 2017, UK police body armour requirements for anatomical coverage for both edged weapon and ballistic threats are now based upon the requirements of UK military. This revised coverage may need additional research to determine minimum distances to essential structures. METHOD: Three entry locations and penetration vectors were chosen using the limited available information in the literature, in combination with a specialist in edged weapons defence. One hundred twenty CT trauma scans of male military service personnel were subsequently analysed to ascertain minimum distances from skin surface to the first structure encountered that is included in essential coverage (heart, aorta, vena cava, liver and spleen) at 3 specific entry points. RESULTS: Individuals ranged between 18 and 46 years, with a mean body mass index of 24.8. The absolute minimum depth from skin surface to a structure within the auspice of essential coverage was 17 mm to the liver in entry point 3 and 19 mm to the heart in entry point 2. CONCLUSIONS: Minimum distances to critical structures were significantly larger than those described in previous studies on civilians. This study will be used to supplement existing evidence to support existing UK police requirements for stab-resistant body armour. Using the weapon entry sites and vectors described in this study, overmatching to a behind armour depth of 17 mm would cover all of this population in this study.

The ballistic performance of bone when impacted by fragments.

Physical models are required to generate the underlying algorithms that populate computer simulations of the effects of explosive fragmenting devices. These models and simulations are used for understanding weapon performance, designing buildings and optimising personal protective equipment. Previous experimental work has investigated the performance of skin and muscle when subjected to fragmentation threats, but limited evidence exists for the performance of bone when impacted by fragments. In the current work, ballistic testing was conducted using two types of internationally recognised steel fragment simulating projectiles (FSPs): (i) 5.5 mm diameter (0.68 g) ball bearing (BBs) and (ii) 1.10 g chisel nosed (CN). These projectiles were fired at isolated swine ribs at impact velocities between 99 and 1265 m/s. Impact events were recorded using a high-speed camera. Selected specimens were analysed post-impact with plain x-radiographs and micro-CT scanning to determine damage to the bone architecture. Bones were perforated with a kinetic energy density (KED) as low as 0.14 J/mm2. Energy transfer to the bone was greater for the CN FSPs, resulting in increased bone damage and the production of secondary bone fragments. The manner in which the bones failed with faster velocity impacts (> 551 m/s; KED > 6.44 J/mm2) was analogous to the behaviour of a brittle material. Slower velocity impacts (< 323 m/s; KED < 1.49 J/mm2) showed a transition in failure mode with the bone displaying the properties of an elastic, plastic and brittle material at various points during the impact. The study gives critical insight into how bone behaves under these circumstances.

The Reconstructive Trauma Surgery Interface Fellowship and its applicability to military and civilian trainees.

The Reconstructive Trauma Surgery Fellowship is a based at the Queen Elizabeth Hospital, Birmingham, and focuses on the multidisciplinary management of major trauma from presentation to discharge. It is unique to the UK in that it provides both management and leadership experience as well as operative surgical skills particularly in terms of reconstruction on complex trauma patients including those from the military. This paper describes the relevance of fellowships in modern surgical training, composition of the reconstructive trauma fellowship and the relevance for both civilian and military trainees.

Does preliminary optimisation of an anatomically correct skull-brain model using simple simulants produce clinically realistic ballistic injury fracture patterns?

Ballistic head injury remains a significant threat to military personnel. Studying such injuries requires a model that can be used with a military helmet. This paper describes further work on a skull-brain model using skulls made from three different polyurethane plastics and a series of skull 'fills' to simulate brain (3, 5, 7 and 10% gelatine by mass and PermaGel™). The models were subjected to ballistic impact from 7.62 × 39 mm mild steel core bullets. The first part of the work compares the different polyurethanes (mean bullet muzzle velocity of 708 m/s), and the second part compares the different fills (mean bullet muzzle velocity of 680 m/s). The impact events were filmed using high speed cameras. The resulting fracture patterns in the skulls were reviewed and scored by five clinicians experienced in assessing penetrating head injury. In over half of the models, one or more assessors felt aspects of the fracture pattern were close to real injury. Limitations of the model include the skull being manufactured in two parts and the lack of a realistic skin layer. Further work is ongoing to address these.

Rapid on-site assessment of specimens by biomedical scientists improves the quality of head and neck fine needle aspiration cytology.

OBJECTIVE: Immediate rapid on-site assessment (ROSA) of fine needle aspiration cytology (FNAC) specimens by biomedical scientists (BMS), the UK equivalent of cytotechnologists, or by pathologists may improve specimen quality and cellular adequacy rates for lymph node, head and neck and thyroid FNAC. The aim of this study was to evaluate the effect of introducing ROSA by BMS in an outpatient clinic setting. METHODS: The adequacy rate and sensitivity of histological diagnosis for lymph node, thyroid and salivary gland FNAC samples were determined before and after the introduction of BMS ROSA. The additional financial costs and time required to perform this service were also estimated. RESULTS: Thirty-one patients underwent ultrasound (US)-guided FNAC with ROSA and 151 without. ROSA reduced the number of FNAC insufficient in quality for diagnosis from 43% to 19% (P = 0.0194). The estimated additional cost for pathology per patient for ROSA was between £52.05 and £70.74, equivalent to €65.40/US $83.90 and €88.89/US $114.0, respectively, an increase of between 28% and 49% from the original cost. ROSA necessitated an additional 6 minutes clinic time per patient, reducing the number of patients that could be seen in an average clinic from 13 to 10 as well as requiring increased laboratory time for FNAC slide assessment. CONCLUSION: ROSA by suitably trained biomedical scientists and with appropriate consultant pathologist support can improve the quality of FNAC sampling for head and neck lesions. Although ROSA resulted in both additional financial and time costs, these are more than likely to be offset by a reduction in patients returning to clinic for repeat FNAC or undergoing unnecessary surgery.

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.

Anthropometric assessment of cervical neurovascular structures using CTA to determine zone-specific vulnerability to penetrating fragmentation injuries.

AIM: To determine military-specific cervical neurovascular and external anthropometric data to scale future numerical injury models of the neck and improve body armour design with a view to prevention or mitigation of combat neck injury. MATERIALS AND METHODS: Contrast-enhanced computed tomography (CT) angiograms of 50 UK servicemen were analysed. Mean diameters and distances from the skin surface were determined for the carotid artery (CA), internal jugular vein (IJV), vertebral artery (VA) and spinal cord (SC) at the three surgical neck zones. Horizontal neck circumference at C6 and three potential vertical cervical anthropometric measurements were analysed to determine which had the least variability between subjects. RESULTS: The diameters of cervical vascular structures are greater and the vessels more superficial as the anatomical plane moves caudally. The SC and VA are better protected than the IJV and CA due to their greater depth and bony coverage, except for the VA in zone 1. CONCLUSION: Future cervical anthropometric assessments should use the vertical angle of mandible to mid-claviclular distance in combination with the horizontal neck circumference as these demonstrated the least variability. Cervical neurovascular structures are least vulnerable posterosuperiorly and therefore extending the posterior aspect of a ballistic helmet inferiorly or adding a nape protector would appear to be less justified. Cervical vessels are most vulnerable in zone 1 and a circumferential collar of ballistic material at least 75 mm high would cover this area in 95% of this population.

How should we manage severe anxiety towards dental treatment in UK service personnel?

Anxiety towards dental treatment is a significant barrier towards care within the United Kingdom Armed Forces. Avoidance of dental treatment results in morbidity, and severe dental infections can lead to systemic disease, which in turn may require hospitalisation. Of greater concern are deployed phobic patients who may develop dental pathology or suffer dental trauma and will likely require evacuation to the UK or a suitable host nation. This has considerable financial implications and in a war setting may place everyone in the evacuation chain at greater risk especially considering that it is not possible to manage these patients in Role 1 or 2 environments. Managing anxiety using either sedation or a general anaesthetic as a long-term management strategy for anxious military patients is simply not practical. This is reflected by current Defence policy stating that service personnel who are unable to tolerate treatment under local anaesthetic (LA) alone should be medically downgraded. However, the situation should ideally be addressed at the time of first recruitment. Currently, despite regulations recommending that potential new military recruits who cannot tolerate routine dentistry under LA should be medically discharged, in reality the subjectivity of such an assessment means this rarely happens. We would instead recommend that following identification of dental phobic recruits in initial training, they be placed in a holding platoon while methods to address their anxiety are explored. This would potentially avoid them entering military service and ultimately being discharged.

Justifying the implementation of intraoperative computed tomography for midface fracture treatment in improving outcomes.

Intraoperative CT scanning is the international standard for treating midface fractures as it allows intraoperative assessment of reduction and fixation. To our knowledge, no NHS hospital in the UK has this facility yet due to the financial and logistical burden of its implementation. The aim of this study was to determine if complications including the requirement for a return to theatre (RTT) could have been predicted from the post-fixation CT scan. All treated midface fractures that had presented to a regionalised major trauma centre within two years (01 January 2020 - 31 December 2021) were identified. Those developing complications including RTT were determined. All postoperative CT scans (including those without complication or RTT) were re-analysed with the clinicians blinded to the outcomes to determine the positive predictive value (PPV) and negative predictive value (NPV) of requiring RTT to alter plate position intraoperatively based on CT scan alone. In all, there were eight episodes of unplanned return to theatre, resulting in an overall RTT rate of 8/119 (6.7%). When only analysing patients treated for orbital fractures this RTT rises to 8/40 (20%). Of those eight patients who had a postoperative CT and required RTT, this could have been predicted in 7/8 (87.5%). A total of 16/44 (36.4%) patients that did not have RTT would have additionally been recommended to have the plate position altered based on CT alone. Based upon those that had a CT, the PPV of CT alone being able to predict those requiring RTT was 40.6% and the NPV 96.2%. Our results would suggest intraoperative CT would likely have prevented eight patients requiring RTT in two years and could have improved outcomes in 16 cases. In preventing RTT as well as potentially improving the outcomes of a further 16 cases in maxillofacial surgery, the purchase of an intraoperative CT scanner could yield net savings of £75534-£114990 over two years.

Spectroscopic ellipsometry as an optical probe of strain evolution in ferroelectric thin films.

Heteroepitaxial strain in ferroelectric thin films is known to have a significant impact on both their low and high frequency dielectric properties. In this paper, we use ex-situ spectroscopic ellipsometry to study the strain evolution with film thickness, and strain relaxation in ferroelectric Ba0.5Sr0.5

Outcomes from penetrating ballistic cervical injury.

AIMS: Ballistic cervical injury has become a significant source of both morbidity and mortality for the deployed UK soldier. The aim of this paper was to document a case series of ballistic cervical wounds to describe the pattern of these injuries and relate them to outcome. METHODS: The records of all UK service personnel sustaining wounds to the neck in Iraq or Afghanistan between 01 August 2004 and 01 January 2008 were analysed following identification by the Joint Theatre Trauma Registry. Blunt or thermal injuries were excluded. RESULTS: The records of 75/76 service personnel sustaining penetrating cervical injury during this period were available for analysis. 56/75 (75%) were due to explosive fragmentation and the remainder due to gunshot wounds (GSW). 33/75 (44%) of soldiers sustained vascular injury, 32/75 (43%) injury to the spine or spinal cord, 29/75 (39%) injury to the larynx or trachea and 11/75 (15%) injury to the pharynx or oesophagus. 14/75 (19%) patients in this series underwent surgery in a hospital facility for treatment of potentially life threatening cervical injuries, with a survival rate after surgery of 12/14 (86%). The overall mortality from this series of battlefield penetrating neck injury was 63%. CONCLUSIONS: Penetrating cervical ballistic injury is a significant source of injury to deployed UK service personnel, predominantly due to neurovascular damage. Neck collars if worn would likely prevent many of the injuries in this case series but such protection is uncomfortable and may interfere with common military tasks. Newer methods of protecting the neck should be investigated that will be acceptable to the deployed UK soldier.

Bioethics in humanitarian disaster relief operations: a military perspective.

The ethical dilemmas faced every day by military personnel working within the NHS will potentially be very different to ones that will be faced in the wake of a humanitarian disaster. Allied to this the potentially differing objectives from military personnel when compared with other healthcare workers in these scenarios and a conflict of ethics could arise.Within this paper, the fundamentals of this conflict will be explored and how working within the military framework can affect clinical decisions. This is a paper commissioned as a part of the humanitarian and disaster relief operations special issue of BMJ Military Health.

Non-surgical management of non-condylar mandibular fractures.

Unlike fractures of the remaining facial skeleton, fractures of the non-condylar part of the mandible are invariably treated surgically, with the potential risk of further iatrogenic injury. There is, however, a substantial evidence gap pertaining to the potential non-surgical management of such injuries. The aim of this study was to determine the outcomes of mandibular fractures treated with non-surgical management. All patients with mandibular fractures who were referred to a large regional major trauma service over a one-year period (1 January-31 December 2021) were identified. Those treated with surgery or who sustained fractures of the condylar portion of the mandible were excluded. Of all the patients referred to our unit with mandibular fractures, 34/155 (22%) underwent non-surgical management. In all cases plain radiographs demonstrated minimal displacement. Thirty-two (94%) fractures were unilateral, of which 24 (70%) involved the angle. Two of 34 patients subsequently required open reduction and internal fixation due to pain that did not improve over time, one of whom declined. A minimally extruded tooth in the fracture line, which altered the occlusion in one additional patient, required minimal reduction of the enamel. The remaining patients healed without complication six weeks after injury. Non- surgical management requires careful case selection and regular follow up, so is of value to only a small proportion of patients. Twenty-two per cent of all mandibular fractures were managed non-surgically at our unit in one year, with a 97% success rate, demonstrating the potential utility of this strategy in carefully selected cases.

Use of hearing protection on military operations.

Noise Induced Hearing Loss (NIHL) continues to be a significant source of morbidity for UK service personnel. The Personal Interfaced Hearing Protection (PIHP) system was procured as an Urgent Operational Requirement primarily to provide a connection to the Personal Role Radio. Through its custom- mould design it was also expected to act as Personal Protective Equipment (PPE) against NIHL in a method that had not been possible previously. The aim of this paper was to evaluate user opinion of the four current methods of hearing protection including PIHP. 108 service personnel serving in a Forward Operating Base in Afghanistan were questioned anonymously using a paper-based questionnaire. The response rate was 78%, reflecting the difficulties in anonymous data collection in an environment such as this. PIHP was perceived to be more practical for use on the ranges or patrolling than the standard methods of hearing protection. Although only 4% were routinely wearing PIHP on patrol, this was related to understandable reluctance in wearing a new system that had only been issued immediately prior to this deployment. Early design problems highlighted by our study, such as changes in the design of the ear-piece to improve retention, have already been implemented. Compliance will be improved through a dedicated educational programme to explain its relevance. Despite the logistical difficulties in providing custom- made ear moulds, the PIHP system must be delivered to all service personnel early in their career so they are confident in its use long before operational deployment. Future research is required to ascertain the effectiveness of PIHP as a method of PPE in reducing the incidence of NIHL.

Physician assistant utilisation in the US Armed Forces: applicability to the UK Defence Medical Services.

Physicians assistants (PAs) are being increasingly utilised by the US Armed Forces both in homeland medical treatment provision as well as while on deployment. In a deployed environment, the USA has the flexibility to interchange doctors with specialty-trained PAs in all roles of care due to their ability to practice autonomously, thereby filling shortfalls created by the lack of specialty physicians. PAs are increasingly being utilised within the UK National Health Service, in similar roles to their US counterparts. This paper postulates that PAs have an equivalent role to play in the future of medical care provision within the UK Defence Medical Services, including on military operations.

Management of devastating ocular trauma--experience of maxillofacial surgeons deployed to a forward field hospital.

Combat-related eye injuries continue to increase in frequency and are generally secondary to Improvised Explosive Devices. Many ocular injuries are potentially preventable by the wearing of ballistic eye protection. The management of penetrating eye trauma is normally outside the routine practice of maxillofacial surgeons in the UK. The aim of this paper is to describe the surgical techniques used in the modern management of devastating ocular trauma including selected case examples managed by British military maxillofacial surgeons deployed to Afghanistan.

Clinical strategies in the management of complex maxillofacial injuries sustained by British military personnel.

The maxillofacial injuries sustained by British troops requiring aeromedical evacuation to the United Kingdom are almost exclusively treated at The Royal Centre for Defence Medicine in Birmingham. As a result the Maxillofacial Department has collectively gained extensive experience in the management of ballistic injuries. In many cases the most successful outcomes have been achieved by using traditional strategies combined with contemporary techniques. This paper will highlight the types of injuries sustained and discuss some cases that typify those the department has managed.

Five months of surgery in the multinational field hospital in Afghanistan with an emphasis on oral and maxillofacial injuries.

The aim of this review was to assess the workload of theatres in the role 3 Multinational Field Hospital in Kandahar, Afghanistan and to identify what period of day most emergency admissions arrived. During the period 05 August 2006 to 21 December 2006, 288 operations were performed on 259 patients and comprised 393 individually quantifiable procedures. 98% of these operations were to treat acute injuries. Oral and Maxillofacial surgeons were involved in 24% of operations. 63% of procedures done at these operations involved upper or lower limbs, 19% the head and neck and 18% involved the torso. An analysis of emergency admissions in November 2006 showed that most occurred between 18.00 and midnight. Although theatre timetabling made provision for this, whenever possible, elective surgery was scheduled for the following morning when emergency injury admissions were at their lowest.

Clinicians' and patients' acceptance of the virtual clinic concept in maxillofacial surgery: a departmental survey.

Virtual clinics have been proposed as a method of reducing costs and improving services in the National Health Service (NHS). The aim of this research was to assess the attitudes of clinicians and patients towards virtual consultations in a department of oral and maxillofacial surgery (OMFS). Patients and clinicians at conventional OMFS adult outpatient clinics were prospectively interviewed using a structured questionnaire. Variables recorded included type of consultation, overall attitude, time travelled, and mode of transport. Patients' notes were assessed retrospectively to check if examinations had been done. A total of 146 patients (100%) completed the surveys, and 108 of them (74%) were amenable to having virtual consultations in the future. Such appointments may have been suitable for 19 patients who did not have examinations. Chi squared analysis showed no relation between type of appointment and preference for a virtual consultation (p=0.087). To introduce a virtual consultation system in our department and to assess its efficacy once implemented, further development and research are required.