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  • Journal article
    Yu X, Azor A, Sharp DJ, Mazdak Get al., 2020,

    Mechanisms of tensile failure of cerebrospinal fluid in blast traumatic brain injury

    , Extreme Mechanics Letters, Vol: 38, Pages: 1-9, ISSN: 2352-4316

    Mechanisms of blast-induced Traumatic Brain Injury (BTBI), particularly those linked to the primary pressure wave, are still not fully understood. One possible BTBI mechanism is cavitation in the cerebrospinal fluid (CSF) caused by CSF tensile failure, which is likely to increase strain and strain rate in the brain tissue near the CSF. Blast loading of the head can generate rarefaction (expansion) waves and rapid head motion, which both can produce tensile forces in the CSF. However, it is not clear which of these mechanisms is more likely to cause CSF tensile failure. In this study, we used a high-fidelity 3-dimensional computational model of the human head to test whether the CSF tensile failure increases brain deformation near the brain/CSF boundary and to determine the key failure mechanisms. We exposed the head model to a frontal blast wave and predicted strain and strain rate distribution in the cortex. We found that CSF tensile failure significantly increased strain and strain rate in the cortex. We then studied whether the rapid head motion or the rarefaction wave causes strain and strain rate concentration in cortex. We isolated these two effects by conducting simulations with pure head motion loading (i.e. prescribing the skull velocity but eliminating the pressure wave) and pure blast wave loading (i.e. eliminating head motion by fixing the skull base). Our results showed that the strain increase in the cortex was mainly caused by head motion. In contrast, strain rate increase was caused by both rapid head motion and rarefaction waves, but head motion had a stronger effect on elevating strain rate. Our results show that rapid motion of the head produced by blast wave is the key mechanism for CSF tensile failure and subsequent concentration of strain and strain rate in cortex. This finding suggests that mitigation of rapid head motion caused by blast loading needs to be addressed in the design of protective equipment in order to prevent the tensile failure

  • Journal article
    Turner S, McGregor A,

    Perceived impact of socket fit on major lower limb prosthetic rehabilitation: a clinician and amputee perspective

    , Archives of Rehabilitation Research and Clinical Translation

    ObjectiveTo determine amputees’ and rehabilitation clinicians’ perspectives on the impact of socket fit and issues caused by ill-fitting sockets throughout lower limb prosthetic rehabilitation.DesignA survey was developed to identify rehabilitation factors and issues for prosthesis wearers and rehabilitation clinicians. Participants opted to participate in a further telephone interview.SettingOnline and across the United Kingdom.ParticipantsLower limb prosthetic wearers and clinicians that are part of a lower limb prosthetic rehabilitation team.InterventionsNot applicable.Main Outcome Measure(s)A survey and an interview to measure the perceived impact of socket fit on lower limb rehabilitation.Results48.0% of amputees and 65.7% of clinicians identified socket fit related issues as the biggest factor impacting rehabilitation. Amputee interviewees focused on the impact of fit on quality of life and the ability to complete daily tasks, whilst clinicians focused on the lack of widespread ability to adjust the socket and gait re-education.ConclusionsSocket fit has a large impact on and is a large source of frustration to amputees and their clinical teams throughout rehabilitation. From the interviews, it became clear that the interpretation of socket fit is different for each person; thus “socket fit” does not mean the same for all.

  • Journal article
    Stewart S, Tenenbaum O, Masouros S, Ramasamy Aet al.,

    Fracture non-union rates across a century of war: a systematic review of the literature

    , BMJ Military Health, ISSN: 2633-3767

    IntroductionFractures have been a common denominator of the injury patterns observed over the past century of warfare. The fractures typified by the blast and ballistic injuries of war lead to high rates of bone loss, soft tissue injury and infection, greatly increasing the likelihood of non-union. Despite this, no reliable treatment strategy for non-union exists. This literature review aims to explore the rates of non-union across a century of conflict and war, in order to determine whether our ability to heal the fractures of war has improved.MethodsA systematic review of the literature was conducted, evaluating the rates of union in fractures sustained in a combat environment over a one hundred year period. Only those fractures sustained through a ballistic or blast mechanism were included. The review was in accordance with the Preferred Items for Systematic Reviews and Meta-Analyses (PRISMA). Quality and bias assessment was also undertaken. ResultsThirty studies met the inclusion criteria, with a total of 3232 fractures described across fifteen different conflicts from the period 1919-2019. Male subjects made up 96% of cases, and tibial fractures predominated (39%). The lowest fracture union rate observed in a series was 50%. Linear regression analysis demonstrated that increasing years had no statistically significant impact on union rate.ConclusionFailure to improve fracture union rates is likely a result of numerous factors, including greater use of blast weaponry and better survivability of casualties. Finding novel strategies to promote fracture healing is a key defence research priority, in order to improve the rates of fractures sustained in a combat environment.

  • Journal article
    Rankin IA, Webster CE, Gibb I, Clasper JC, Masouros SDet al., 2020,

    Pelvic injury patterns in blast: morbidity and mortality.

    , J Trauma Acute Care Surg

    INTRODUCTION: Pelvic trauma has emerged as one of the most severe injuries to be sustained by the victim of a blast insult. The incidence and mortality due to blast-related pelvic trauma is not known, and no data exist to assess the relative risk of clinical or radiological indicators of mortality. METHOD: The UK Joint Theatre Trauma Registry was interrogated to identify those sustaining blast-mediated pelvic fractures during the conflicts in Iraq and Afghanistan, from 2003 to 2014, with subsequent Computed Tomography image analysis. Casualties that sustained more severe injuries remote to the pelvis were excluded. RESULTS: 159 casualties with a 36% overall mortality rate were identified. Pelvic vascular injury, unstable pelvic fracture patterns, traumatic amputation, and perineal injury were higher in the dismounted fatality group (p<0.05). All fatalities sustained a pelvic vascular injury. Pelvic vascular injury had the highest relative risk of death for any individual injury and an associated mortality of 56%. Dismounted casualties that sustained unstable pelvic fracture patterns, traumatic amputation and perineal injury were at three times greater risk (relative risk 3.00, 95% CI 1.27 - 7.09) to have sustained a pelvic vascular injury than those that did not sustain these associated injuries. Opening of the pubic symphysis and at least one sacroiliac joint was significantly associated with pelvic vascular injury (p<0.001), and the lateral displacement of the sacroiliac joints was identified as a fair predictor of pelvic vascular injury (AUROC: 0.73). CONCLUSION: Dismounted blast casualties with pelvic fracture are at significant risk of a non-compressible pelvic vascular injury. Initial management of these patients should focus upon controlling non-compressible pelvic bleeding. Clinical and radiological predictors of vascular injury and mortality suggest that mitigation strategies aiming to attenuate lateral displacement of the pelvis following blast are l

  • Journal article
    Hopkins M, Vaidyanathan R, McGregor AH, 2020,

    Examination of the performance characteristics of velostat as an in-socket pressure sensor

    , IEEE Sensors Journal, Pages: 1-1, ISSN: 1530-437X

    Velostat is a low-cost, low-profile electrical bagging material with piezoresistive properties, making it an attractive option for in-socket pressure sensing. The focus of this research was to explore the suitability of a Velostat-based system for providing real-time socket pressure profiles. The prototype system performance was explored through a series of bench tests to determine properties including accuracy, repeatability and hysteresis responses, and through participant testing with a single subject. The fabricated sensors demonstrated mean accuracy errors of 110 kPa and significant cyclical and thermal drift effects of up to 0.00715 V/cycle and leading to up to a 67% difference in voltage range respectively. Despite these errors the system was able to capture data within a prosthetic socket, aligning to expected contact and loading patterns for the socket and amputation type. Distinct pressure maps were obtained for standing and walking tasks displaying loading patterns indicative of posture and gait phase. The system demonstrated utility for assessing contact and movement patterns within a prosthetic socket, potentially useful for improvement of socket fit, in a low cost, low profile and adaptable format. However, Velostat requires significant improvement in its electrical properties before proving suitable for accurate pressure measurement tools in lower limb prosthetics.

  • Journal article
    Nguyen TT, Carpanen D, Stinner D, Rankin I, Ramasamy A, Breeze J, Proud W, Clasper J, Masouros Set al., 2020,

    The risk of fracture to the tibia from a fragment simulating projectile

    , Journal of The Mechanical Behavior of Biomedical Materials, Vol: 102, ISSN: 1751-6161

    Penetrating injuries due to fragments energised by an explosive event are life threatening and are associated with poor clinical and functional outcomes. The tibia is the long bone most affected in survivors of explosive events, yet the risk of penetrating injury to it has not been quantified. In this study, an injury-risk assessment of penetrating injury to the tibia was conducted using a gas-gun system with a 0.78-g cylindrical fragment simulating projectile. An ovine tibia model was used to generate the injury-risk curves and human cadaveric tests were conducted to validate and scale the results of the ovine model. The impact velocity at 50% risk (±95% confidence intervals) for EF1+, EF2+, EF3+, and EF4+ fractures to the human tibia – using the modified Winquist-Hansen classification – was 271 ± 30, 363 ± 46, 459 ± 102, and 936 ± 182 m/s, respectively. The scaling factor for the impact velocity from cadaveric ovine to human was 2.5. These findings define the protection thresholds to improve the injury outcomes for fragment penetrating injury to the tibia.

  • Journal article
    Yu X, Ghajari M, 2019,

    An assessment of blast modelling techniques for injury biomechanics research

    , International Journal for Numerical Methods in Biomedical Engineering, Vol: 35, Pages: 1-15, ISSN: 1069-8299

    Blast-induced Traumatic Brain Injury (TBI) has been affecting combatants and civilians. The blast pressure wave is thought to have a significant contribution to blast related TBI. Due to the limitations and difficulties of conducting blast tests on surrogates, computational modelling has been used as a key method for exploring this field. However, the blast wave modelling methods reported in current literature have drawbacks. They either cannot generate the desirable blast pressure wave history, or they are unable to accurately simulate the blast wave/structure interaction. In addition, boundary conditions, which can have significant effects on model predictions, have not been described adequately. Here, we critically assess the commonly used methods for simulating blast wave propagation in air (open-field blast) and its interaction with the human body. We investigate the predicted blast wave time history, blast wave transmission and the effects of various boundary conditions in 3 dimensional (3D) models of blast prediction. We propose a suitable meshing topology, which enables accurate prediction of blast wave propagation and interaction with the human head and significantly decreases the computational cost in 3D simulations. Finally, we predict strain and strain rate in the human brain during blast wave exposure and show the influence of the blast wave modelling methods on the brain response. The findings presented here can serve as guidelines for accurately modelling blast wave generation and interaction with the human body for injury biomechanics studies and design of prevention systems.

  • Journal article
    Koziakova M, Harris K, Edge C, Franks N, White I, Dickinson Ret al., 2019,

    Noble gas neuroprotection: Xenon and argon protect against hypoxic-ischaemic injury in rat hippocampus in vitro via distinct mechanisms

    , British Journal of Anaesthesia, Vol: 123, Pages: 601-609, ISSN: 1471-6771

    BackgroundNoble gases may provide novel treatments for neurological injuries such as ischaemic and traumatic brain injury. Few studies have evaluated the complete series of noble gases under identical conditions in the same model.MethodsWe used an in vitro model of hypoxia–ischaemia to evaluate the neuroprotective properties of the series of noble gases, helium, neon, argon, krypton, and xenon. Organotypic hippocampal brain slices from mice were subjected to oxygen-glucose deprivation, and injury was quantified using propidium iodide fluorescence.ResultsBoth xenon and argon were equally effective neuroprotectants, with 0.5 atm of xenon or argon reducing injury by 96% (P<0.0001), whereas helium, neon, and krypton were devoid of any protective effect. Neuroprotection by xenon, but not argon, was reversed by elevated glycine.ConclusionsXenon and argon are equally effective as neuroprotectants against hypoxia–ischaemia in vitro, with both gases preventing injury development. Although xenon's neuroprotective effect may be mediated by inhibition of the N-methyl-d-aspartate receptor at the glycine site, argon acts via a different mechanism. These findings may have important implications for their clinical use as neuroprotectants.

  • Journal article
    Rankin IA, Thuy-Tien N, Carpanen D, Clasper JC, Masouros SDet al., 2019,

    Restricting Lower Limb Flail is Key to Preventing Fatal Pelvic Blast Injury

    , ANNALS OF BIOMEDICAL ENGINEERING, Vol: 47, Pages: 2232-2240, ISSN: 0090-6964
  • Journal article
    Stewart S, Darwood A, Masouros S, Higgins C, Ramasamy Aet al.,

    Mechanotransduction in osteogenesis: current concepts and therapeutic applications

    , Bone and Joint Research, ISSN: 2046-3758

    Bone is one of the most highly adaptive tissues in the body, possessing the capability to alter its morphology and function in response to stimuli in its surrounding environment. The ability for bone to sense external mechanical stimuli and convert it in to biochemical response which ultimately alters the phenotype and function of the cell is described as mechanotransduction. This review aims to describe the fundamental physiology and biomechanisms that occur to induce osteogenic adaptation of a cell following application of a physical stimulus. Significant developments have been made in recent years of our understanding of how cells orchestrate this complex interplay of processes and have become the focus of research in osteogenesis. We will discuss current areas of pre-clinical and clinical research for harnessing the mechanotransductive properties of cells and applying them therapeutically, both in the context of fracture healing and de novo bone formation in situations such as non-union.

  • Conference paper
    Campos-Pires R, Mohamed-Ali N, Balaet M, Aldhoun J, Abelleira-Hervas L, Aitken P, Edge C, Franks N, Dickinson Ret al., 2019,

    Xenon prevents early neuronal loss and neuroinflammation in a rat model of traumatic brain injury

    , BJA Research Forum / Anaesthetic Research Society, Publisher: Elsevier, Pages: e508-e509, ISSN: 0007-0912
  • Conference paper
    Campos-Pires R, Hirnet T, Valeo F, Ong BE, Radyushkin K, Aldhoun J, Saville J, Edge CJ, Franks NP, Thal SC, Dickinson Ret al., 2019,

    XENON PREVENTS NEURODEGENERATION AND LATE-ONSET COGNITIVE IMPAIRMENT, AND IMPROVES SURVIVAL AFTER TRAUMATIC BRAIN INJURY IN MICE

    , 37th Annual National Neurotrauma Symposium, Publisher: MARY ANN LIEBERT, INC, Pages: A47-A47, ISSN: 0897-7151
  • Conference paper
    Campos-Pires R, Yonis A, Pau A, Macdonald W, Harris K, Franks N, Edge C, Dickinson Ret al., 2019,

    Delayed xenon treatment prevents injury development following blast-neurotrauma in vitro

    , 37th Annual National Neurotrauma Symposium, Publisher: Mary Ann Liebert, Pages: A40-A41, ISSN: 0897-7151
  • Conference paper
    Campos-Pires R, Mohamed-Ali N, Balaet M, Aldhoun J, Abelleira-Hervas L, Aitken P, Edge CJ, Franks NP, Dickinson Ret al., 2019,

    XENON REDUCES SECONDARY INJURY, PREVENTS NEURONAL LOSS AND NEUROINFLAMMATION IN A RAT MODEL OF TRAUMATIC BRAIN INJURY

    , 37th Annual National Neurotrauma Symposium, Publisher: MARY ANN LIEBERT, INC, Pages: A116-A116, ISSN: 0897-7151
  • Journal article
    Campos-Pires R, Hirnet T, Valeo F, Ong BE, Radyushkin K, Aldhoun J, Saville J, Edge CJ, Franks NP, Thal SC, Dickinson Ret al., 2019,

    Xenon improves long-term cognitive function, reduces neuronal loss and chronic neuroinflammation, and improves survival after traumatic brain injury in mice

    , British Journal of Anaesthesia, Vol: 123, Pages: 60-73, ISSN: 0007-0912
  • Conference paper
    Nguyen TT, Masouros S, 2019,

    Penetration of Blast Fragments to the Thorax

    , International Research Council On Biomechanics Of Injury
  • Conference paper
    Nguyen TT, Masouros S,

    Penetration of Blast Fragments to the Thorax

    , International Research Council On Biomechanics Of Injury 2019
  • Conference paper
    Nguyen TT, Meek G, Masouros S, 2019,

    Blast Fragment Protection for The Extremities

    , Light Weight Armour for Defense & Security 2019
  • Conference paper
    Campos-Pires R, Mohamed-Ali N, Balaet M, Aldhoun J, Abelleira-Hervas L, Aitken P, Edge C, Franks N, Dickinson Ret al., 2019,

    Xenon Treatment Reduces Secondary Injury Development and Prevents Neuronal Loss and Microglial Proliferation in a Rat Model of Traumatic Brain Injury

    , 13th World Conference on Brain injury, Pages: 222-222, ISSN: 0269-9052
  • Conference paper
    Campos-Pires R, Hirnet T, Valeo F, Ong BE, Saville J, Radyushkin K, Edge C, Franks N, Thal S, Dickinson Ret al., 2019,

    Xenon Treatment Prevents Late Onset Cognitive Impairment and Improves Survival Following Traumatic Brain Injury in Mice

    , 13th World Conference on Brain Injury, Pages: 220-220, ISSN: 0269-9052

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