Preliminary effect of projectile yaw on extremity gunshot wounding in a cadaveric animal model: a serendipitous study.

Gunshot wounding (GSW) is capable of causing devastating tissue injuries by delivering kinetic energy (KE) through the contact surface area of a projectile. The contact surface area can be increased by yaw, deformation and fragmentation, all of which may be caused by any intermediate layers struck by the projectile prior to entering its target. This study aims to describe whether projectile yaw occurring before penetration of a cadaveric animal limb model causes greater damage with or without clothing layers present using 5.45 × 39 mm projectiles. In total, 12 fallow deer hind limbs were shot, further divided into 4 with no clothing layers (Cnil), 4 with a single clothing layer (Cmin) and 4 with maximum clothing layers (Cmax) as worn on active duty by UK military personnel. Contrast computed tomography (CT) of limbs was used to measure permanent cavity size and the results were compared using analysis of variance (ANOVA). No significant differences were found among clothing states for each series of measurements taken, with greater cavity sizes noted in all clothing states. This is in contrast to previous work looking at symmetrically flying projectiles in the same model, where a larger permanent cavity was found only with Cmax present. Projectile yaw is therefore likely to be a key variable with regard to causation of damage within this extremity wound model.

Ballistic research techniques: visualizing gunshot wounding patterns.

There are difficulties associated with mapping gunshot wound (GSW) patterns within opaque models. Depending on the damage measurement parameters required, there are multiple techniques that can provide methods of "seeing" the GSW pattern within an opaque model. The aim of this paper was to test several of these techniques within a cadaveric animal limb model to determine the most effective. The techniques of interest were flash X-ray, ultrasound, physical dissection, and computed-tomography (CT). Fallow deer hind limbs were chosen for the model with four limbs used for each technique tested. Quarantined 7.62 × 39 mm ammunition was used for each shot, and each limb was only shot once, on an outdoor range with shots impacting at muzzle velocity. Flash X-ray provided evidence of yaw within the limb during the projectile's flight; ultrasound though able to visualise the GSW track, was too subjective and was abandoned; dissection proved too unreliable due to the tissue being cadaveric so also too subjective; and lastly, CT with contrast provided excellent imaging in multiple viewing planes and 3D image reconstruction; this allowed versatile measurement of the GSW pattern to collect dimensions of damage as required. Of the different techniques examined in this study, CT with contrast proved the most effective to allow precise GSW pattern analysis within a cadaveric animal limb model. These findings may be beneficial to others wishing to undertake further ballistic study both within clinical and forensic fields.

The effect of military clothing on gunshot wounding patterns in gelatine.

With no two gunshot wounds (GSW) being the same, novel research into wound ballistics is challenging. It is evident that the majority of previous wound ballistic research has been conducted without the presence of clothing. Whilst the effect of clothing on wound contamination has been explored, there is a paucity of literature examining the effect of clothing on GSW patterns. The aim of this study was to test the effect of Multi-Terrain Pattern (MTP) UK military clothing on GSW patterns within calibrated blocks of 10% by mass gelatine, using two types of ammunition commonly used in recent conflicts-7.62 × 39 mm and 5.45 × 39 mm. In total, 36 blocks were shot, 18 by each projectile type, further divided into 6 with no clothing layers (Cnil), 6 with a single clothing layer (Cmin) and 6 with maximum clothing layers (Cmax) worn on active duty. Blocks were analysed with high-speed video and dissection to capture measurements of damage, and results compared using analysis of variance (ANOVA). Results showed significantly different damage measurements within blocks with Cmax for both ammunition types compared to the other clothing states. This may result in GSWs that require more extensive surgical management, inviting further study.

The effect of military clothing on gunshot wound patterns in a cadaveric animal limb model.

The majority of injuries in survivors of gunshot wounds (GSW) are typically to the extremities. Novel wound ballistic research is encouraged to try and capture corporate knowledge on the management of these injuries gained during recent conflicts and understand the wounding patterns seen. With recent work examining the effect of UK military clothing on extremity GSW patterns in a synthetic model, a model with greater biofidelity is needed for ballistic testing. The aim of this study was to assess the effect of UK military clothing on GSW patterns within a cadaveric animal limb model using two types of ammunition commonly used in recent conflicts-7.62 × 39 mm and 5.45 × 39 mm. In total, 24 fallow deer hind limbs were shot, 12 by 7.62 mm projectiles and the remaining 12 shot by 5.45 mm projectiles, further divided into four with no clothing layers (Cnil), four with a single clothing layer (Cmin) and four with maximum clothing layers (Cmax) as worn on active duty by UK military personnel. Limbs were analysed after ballistic impact using contrast CT scanning to obtain measurements of permanent cavity damage, and results were compared using analysis of variance (ANOVA). Results showed significantly different damage measurements within limbs with Cmax for both ammunition types compared with the other clothing states. This may result in GSWs that require more extensive surgical management, and invites further study.

A clinically applicable tool for rapidly estimating muscle volume using ultrasound images.

PURPOSE: This study aimed to identify a safe, rapid, and accessible method of estimating muscle volume of key lower limb muscle groups to reduce the time-demand of acquiring this measurement and potentially facilitate its application as a clinical monitoring tool. METHODS: Unilateral MRI images were acquired from the 12th thoracic vertebrae to the base of the foot in 18 recreationally active males. Panoramic B-mode ultrasound images were acquired from the same leg at the mid-hip, 25%, 50%, and 75% of thigh length, and 25% of shank length. Body mass, height, limb lengths, and circumferences at the sites corresponding to the ultrasound images were acquired. A single investigator manually analysed all images. Regression analyses were conducted to identify models for estimating volume of the hip extensor, knee extensor and flexor, and ankle plantarflexor muscle groups. RESULTS: Models were developed for estimating hip extensor (SEE = 8.92%, R2 = 0.690), knee extensor (SEE = 5.24%, R2 = 0.707) and flexor (SEE = 7.89%, R2 = 0.357), and ankle plantarflexor (SEE = 10.78%, R2 = 0.387) muscle group volumes. The hip and knee extensor models showed good potential for generalisation. Systematic error was observed for the knee flexor and ankle plantarflexor models. CONCLUSIONS: Hip extensor, knee extensor and flexor, and ankle plantarflexor muscle group volumes can be estimated using B-mode ultrasound images and anthropometric measurements. The error shown for each of the models was sufficient to identify previously reported differences in muscle volume due to training or injury, supporting their clinical application.

Management of conflict injuries to the upper limb. Part 2: reconstruction and managing complications.

This is the second of a two-part review article on the management of conflict injuries, focused on the reconstructive strategies for bone, nerve and soft tissue and to provide guidance on assessing and managing common complications associated with complex upper limb injuries. Following assessment and early surgical management, the conflict casualty will require further wound evaluation and planning prior to definitive reconstruction of limb injuries. Surgical management of the upper limb injury should aim, where possible, to preserve the limb and allow functional reconstruction. The principles of the second look procedure are to assess wound progression, further reduce the risk of infection and plan definitive reconstruction with adequate soft tissue cover. The prerequisites for successful surgical reconstruction are a stable patient, combined orthoplastic surgery expertise supported by physiotherapists and hand therapists.

Management of conflict injuries to the upper limb. Part 1: assessment and early surgical care.

Upper limb injuries are common in conflict zones. The functions of the upper limb are impossible to replicate with prosthetic replacement and wherever possible attempts should be made to preserve the limb with further secondary reconstruction aimed at restoration of function. Casualty assessment, haemorrhage control and resuscitation are simultaneously undertaken at the receiving medical facility. Primary surgical management involves decontamination and debridement, skeletal stabilization, restoration of vascularity, compartment fasciotomy where indicated and wound temporization with dressings. Operative findings and interventions should be documented and if evacuation of the casualty is possible, copies should be provided in the medical records to facilitate communication in the chain of care. Secondary procedures are required for further assessment and debridement prior to planning reconstruction and definitive fracture stabilization, nerve repair, wound cover or closure.

Hexametaphosphate as a potential therapy for the dissolution and prevention of kidney stones.

The incidence of kidney stones is increasing worldwide, and recurrence is common (50% within 5 years). Citrate, the current gold standard therapy, which is usually given as potassium or sodium salts, is used because it raises urine pH and chelates calcium, the primary component of up to 94% of stones. In this study hexametaphosphate (HMP), a potent calcium chelator, was found to be 12 times more effective at dissolving calcium oxalate, the primary component of kidney stones, than citrate. HMP was also observed to be effective against other common kidney stone components, namely calcium phosphate and struvite (magnesium ammonium phosphate). Interestingly, HMP was capable of raising the zeta potential of calcium oxalate particles from -15.4 to -34.6 mV, which may prevent stone growth by aggregation, the most rapid growth mechanism, and thus avert occlusion. Notably, HMP was shown to be up to 16 times as effective as citrate at dissolving human kidney stones under simulated physiological conditions. It may thus be concluded that HMP is a promising potential therapy for calcium and struvite kidney stones.

Bedside, Benchtop, and Bioengineering: Physicochemical Imaging Techniques in Biomineralization.

The need to quantify physicochemical properties of mineralization spans many fields. Clinicians, mineralization researchers, and bone tissue bioengineers need to be able to measure the distribution, quantity, and the mechanical and chemical properties of mineralization within a wide variety of substrates from injured muscle to electrospun polymer scaffolds and everything in between. The techniques available to measure these properties are highly diverse in terms of their complexity and utility. Therefore it is of the utmost importance that those who intend to use them have a clear understanding of the advantages and disadvantages of each technique and its appropriateness to their specific application. This review provides all of this information for each technique and uses heterotopic ossification and engineered bone substitutes as examples to illustrate how these techniques have been applied. In addition, we provide novel data using advanced techniques to analyze human samples of combat related heterotopic ossification.

Pre-clinical evaluation of therapies to prevent or treat bone non-union: a systematic review protocol.

BACKGROUND: Non-union of fractured bone is a major cause of morbidity in the orthopaedic population. Despite this, optimal management of non-union is still unclear and remains a significant clinical challenge. Research continues in animal models in an attempt to identify an effective clinical treatment. The proposed systematic review will evaluate current therapies of bone non-union in animal models, in order to identify those that may translate successfully to clinical therapies. METHODS/DESIGN: The methodology for the systematic review will be in accordance with standard guidelines. All potential sources for pre-clinical studies will be interrogated and the search strategy written in conjunction with a specialist in this field. Data extraction will be conducted by two reviewers to minimise bias. Analysis will be predominantly qualitative because of the heterogeneity that is likely to exist between the studies. However, quantitative synthesis will be performed where homogeneity in a sub-group of studies exists. Quality assessment will be undertaken utilising a risk of bias tool. DISCUSSION: To date, there has not been a systematic review addressing bone non-union therapies in animal models despite the plethora of pre-clinical research currently being undertaken. This protocol details and outlines the methodology and justification for such a review.

The effects of repeated dosing with 7.5% sodium chloride/6% dextran following uncontrolled intra-abdominal hemorrhage.

The use of hypertonic saline Dextran (HSD) for resuscitation following trauma has many potential benefits, especially for the treatment of military casualties, but there is very limited data on the responses following multiple dosing with this fluid. The effects of a second dose of hypertonic saline dextran for resuscitation of uncontrolled intra-abdominal haemorrhage were studied in an experimental model. Under general anaesthesia, 17 large white pigs (weight range, 48-67 kg) were subjected to uncontrolled hemorrhage produced by a tear in the common iliac artery. This resulted in a significant (P < 0.01) reduction of both mean arterial pressure (MAP) and cardiac index. One hour after injury, animals were assigned to one of three groups, receiving either no resuscitation (Group A), or two doses of HSD (at a dose rate of 4 mL/kg), administered either 1 and 4 h after injury (Group B) or 1 and 7 h after injury (Group C). Animals were monitored for 12 h post-injury. A second infusion of HSD caused a significant hypernatremia and diuresis (P< 0.01) in both Groups B and C. There was a non-significant rise in MAP in both treatment groups, and in Group B only, there was a significant increase in cardiac index (P= 0.014). It is concluded that repeat administration of HSD for the resuscitation of uncontrolled hemorrhage results in limited cardiovascular improvements, but that the metabolic sequelae are potentially detrimental to survival.