Injuries from combat explosions in Iraq: injury type, location, and severity

Systemic inflammation following traumatic injury and its impact on neuroinflammatory gene expression in the rodent brain

BACKGROUND

Trauma can result in systemic inflammation that leads to organ dysfunction, but the impact on the brain, particularly following extracranial insults, has been largely overlooked.

METHODS

Building upon our prior findings, we aimed to understand the impact of systemic inflammation on neuroinflammatory gene transcripts in eight brain regions in rats exposed to (1) blast overpressure exposure [BOP], (2) cutaneous thermal injury [BU], (3) complex extremity injury, 3 hours (h) of tourniquet-induced ischemia, and hind limb amputation [CEI+tI+HLA], (4) BOP+BU or (5) BOP+CEI and delayed HLA [BOP+CEI+dHLA] at 6, 24, and 168 h post-injury (hpi).

RESULTS

Globally, the number and magnitude of differentially expressed genes (DEGs) correlated with injury severity, systemic inflammation markers, and end-organ damage, driven by several chemokines/cytokines (Csf3, Cxcr2, Il16, and Tgfb2), neurosteroids/prostaglandins (Cyp19a1, Ptger2, and Ptger3), and markers of neurodegeneration (Gfap, Grin2b, and Homer1). Regional neuroinflammatory activity was least impacted following BOP. Non-blast trauma (in the BU and CEI+tI+HLA groups) contributed to an earlier, robust and diverse neuroinflammatory response across brain regions (up to 2-50-fold greater than that in the BOP group), while combined trauma (in the BOP+CEI+dHLA group) significantly advanced neuroinflammation in all regions except for the cerebellum. In contrast, BOP+BU resulted in differential activity of several critical neuroinflammatory-neurodegenerative markers compared to BU. t-SNE plots of DEGs demonstrated that the onset, extent, and duration of the inflammatory response are brain region dependent. Regardless of injury type, the thalamus and hypothalamus, which are critical for maintaining homeostasis, had the most DEGs. Our results indicate that neuroinflammation in all groups progressively increased or remained at peak levels over the study duration, while markers of end-organ dysfunction decreased or otherwise resolved.

CONCLUSIONS

Collectively, these findings emphasize the brain's sensitivity to mediators of systemic inflammation and provide an example of immune-brain crosstalk. Follow-on molecular and behavioral investigations are warranted to understand the short- to long-term pathophysiological consequences on the brain, particularly the mechanism of blood-brain barrier breakdown, immune cell penetration-activation, and microglial activation.

Clinical Trajectories of Comorbidity Associated With Military-Sustained Mild Traumatic Brain Injury: Pre- and Post-Injury

BACKGROUND AND OBJECTIVE

In the US military, traumatic brain injury (TBI) is of distinct importance, at home and in the deployed setting, and is considered a "signature injury of the wars in Afghanistan and Iraq." Since 2000, an estimated 468 424 service members (SMs) have been diagnosed with at least one TBI. We examined the clinical trajectories of a group of 18 comorbidities before and after a military-sustained mild TBI (mTBI).

METHODS

Without making assumptions on causality, a group of 18 conditions often co-occurring with mTBI were identified through literature review and TBI subject matter workgroup consensus. Using data from Military Health System Data Repository, we identified SMs whose first lifetime military mTBI occurred between October 1, 2016, and October 30, 2019. Correlation analyses were used to determine the linear relationship between comorbidities prior to and after mTBI diagnosis. Changes in the period prevalence of comorbidities was calculated.

RESULTS

We identified 42 018 SMs with a first lifetime military mTBI, of which 77.6% had at least one comorbidity. Identified SMs were mostly young (46.1% ages 18-24 years), male (81.4%), and White (64.1%). Up to 180 days prior to an mTBI, the most frequently identified conditions were sleep-related conditions (21.7%), headaches (19.4%), posttraumatic stress disorders (PTSDs) (17.8%), anxiety disorders (11.3%), and cervicogenic disorders (eg, cervicalgia) (10.9%). In the period following mTBI diagnosis, the prevalence of diagnosed conditions increased, especially for visual disturbances (327.2%), cognitive conditions (313.9%), vestibular conditions (192.6%), those related to headache (152.2%), and hearing (72.9%). Sleep-related conditions showed moderate positive correlation with a group of co-occurring conditions, led by cognitive conditions (ϕc = 0.50), anxiety disorders (ϕc = 0.42), PTSDs (ϕc =0.43), and headaches and related conditions (ϕc = 0.38).

CONCLUSION

Results indicate that caring for SMs with mild TBI requires a holistic approach, one that considers the complex nature of SM conditions, prior to sustaining their mTBI, as well as after injury. We found a complex correlation of conditions that suggest SMs with mTBI are undergoing a multifaceted experience, one that may require the development of a targeted multidimensional clinical practice recommendation and practice.

Sex Differences in Postinjury Health Profiles Among U.S. Military Personnel Following Deployment-Related Concussion

Background: Women in the U.S. military are now authorized to serve in direct combat occupations. This may increase their risk of combat injuries, such as concussion, in future conflicts. Knowledge of sex differences in health profiles after concussion is paramount for military medical planning efforts. The purpose of this study was to assess sex-related differences in health profiles among U.S. military personnel following deployment-related concussion. Materials and Methods: We conducted a retrospective study of service members who sustained a concussion during combat deployment between 2004 and 2013. Postinjury diagnoses were abstracted from outpatient encounters in electronic health records for 24 months after concussion. We used hierarchical clustering to identify clusters, termed "health profiles," and logistic regression to determine whether sex predicted membership in the health profiles. Results: The study sample included 346 women and 4536 men with deployment-related concussion. Five postinjury health profiles were identified and classified as no morbidity, back pain, tinnitus/memory loss, posttraumatic stress disorder/postconcussion syndrome, and multimorbidity. Women relative to men had higher odds of membership in the back pain (odds ratio [OR] = 1.32; 95% confidence interval [CI] = 1.05-1.67) and multimorbidity profiles (OR = 1.44; 95% CI = 1.03-2.00) and lower odds than men in the tinnitus/memory loss profile (OR = 0.62; 95% CI = 0.42-0.91). Conclusions: Postinjury health profiles among U.S. service members differ by sex following deployment-related concussion, particularly with a higher burden of multimorbidity among women than men, which may require interdisciplinary care. Women also had higher odds of membership in the back pain profile and lower odds in the tinnitus/memory loss profile than men. To prepare for future military operations where women may have greater exposure to combat, continued research elucidating health-related sex differences after deployment-related concussion is imperative.

Demographics and Comorbidities of United States Service Members with Combat-Related Lower Extremity Limb Salvage

INTRODUCTION

This retrospective study describes the demographics and injury characteristics of a recently identified cohort of US Service members with combat-related lower extremity limb salvage (LS).

METHODS

US Service members with combat trauma were identified from the Expeditionary Medical Encounter Database and Military Health System Data Repository and stratified into primary amputation (PA), LS, and non-threatened limb trauma (NTLT) cohorts based on ICD-9 codes. Disparities in demographic factors and injury characteristics were investigated across cohorts and within the LS cohort based on limb retention outcome.

RESULTS

Cohort demographics varied by age but not by sex, branch, or rank. The mechanism of injury and injury characteristics were found to be different between the cohorts, with the LS cohort exhibiting more blast injuries and greater injury burden than their peers with NTLT. A sub-analysis of the LS population revealed more blast injuries and fewer gunshot wounds in those that underwent secondary amputation. Neither demographic factors nor total injury burden varied with limb retention outcome, despite slight disparities in AIS distribution within the LS cohort.

CONCLUSIONS

In accordance with historic dogma, the LS population presents high injury severity. Demographics and injury characteristics are largely invariant with respect to limb retention outcomes, despite secondary amputation being moderately more prevalent in LS patients with blast-induced injuries. Further study of this population is necessary to better understand the factors that impact the outcomes of LS in the Military Health System.

All-cause and cause-specific mortality rates after severe extremity injuries among previously deployed active duty service members

BACKGROUND

Previous research has shown that active duty military personnel who sustain extremity injuries while in service are at elevated risk for serious physical and psychological health issues that could affect their long-term functioning and quality of life yet longer-term mortality has not been studied in this population.

OBJECTIVE

To determine whether rates of all-cause and cause-specific mortality are elevated for active duty U.S. service members who sustained traumatic limb injuries in service, compared to the broader population of deploying service members. To assess differences in mortality rates between service members with traumatic limb injuries that did versus did not result in amputation.

DESIGN

Retrospective cohort study; archival Department of Defense deployment, personnel, medical, and death records were combined and analyzed. Standardized mortality ratios (SMR) adjusted for age, sex, and ethnoracial group, along with associated 95% confidence intervals (CIs), were calculated to directly compare all-cause and cause-specific mortality rates in each of the two injury groups to rates in the total study population.

SETTING

Not applicable.

PARTICIPANTS

Service members who deployed in support of the global war on terror between 2001 and 2016 were eligible for inclusion; the final sample included 1,875,206 individuals surveilled through 2019.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

All-cause and cause-specific mortality rates.

RESULTS

Overall, the number of deaths was over three times higher than expected among service members with amputations (SMR = 3.01; CI: 2.36-3.65), and nearly two times higher among those with serious limb injuries not resulting in amputation (SMR = 1.72; CI: 1.54-1.90) when compared to the larger study population. Rates for both internal and external causes of death were significantly elevated among those with limb injuries.

CONCLUSIONS

Long-term mortality rates are elevated among service members with traumatic limb injuries, though mortality patterns may differ based on whether the injury results in amputation. Although further research into causal mechanisms is needed, these results may inform the development of interventions to improve long-term health outcomes among injured military personnel.

Repetitive, but Not Single, Mild Blast TBI Causes Persistent Neurological Impairments and Selective Cortical Neuronal Loss in Rats

Exposure to repeated mild blast traumatic brain injury (mbTBI) is common in combat soldiers and the training of Special Forces. Evidence suggests that repeated exposure to a mild or subthreshold blast can cause serious and long-lasting impairments, but the mechanisms causing these symptoms are unclear. In this study, we characterise the effects of single and tightly coupled repeated mbTBI in Sprague-Dawley rats exposed to shockwaves generated using a shock tube. The primary outcomes are functional neurologic function (unconsciousness, neuroscore, weight loss, and RotaRod performance) and neuronal density in brain regions associated with sensorimotor function. Exposure to a single shockwave does not result in functional impairments or histologic injury, which is consistent with a mild or subthreshold injury. In contrast, exposure to three tightly coupled shockwaves results in unconsciousness, along with persistent neurologic impairments. Significant neuronal loss following repeated blast was observed in the motor cortex, somatosensory cortex, auditory cortex, and amygdala. Neuronal loss was not accompanied by changes in astrocyte reactivity. Our study identifies specific brain regions particularly sensitive to repeated mbTBI. The reasons for this sensitivity may include exposure to less attenuated shockwaves or proximity to tissue density transitions, and this merits further investigation. Our novel model will be useful in elucidating the mechanisms of sensitisation to injury, the temporal window of sensitivity and the evaluation of new treatments.

Blast Injury Patterns Among Israel Defense Forces Fatalities

INTRODUCTION

The incidence of blast injuries on the battlefield has risen over the last several decades. In order to improve prevention and treatment, it is essential to understand the severity and bodily distribution of these injuries. This study aims to characterize blast injury patterns among IDF fatalities.

MATERIALS AND METHODS

This is a descriptive, retrospective study on postmortem reports of military-blast fatalities between the years 1982 and 2021. Body regions injured according to the Abbreviated Injury Scale (AIS) were described. The frequency of body region injury combinations was mapped, and the correlation between injured body regions was calculated using Pearson's coefficient. Analysis of a subgroup with a postmortem computed tomography (CT-PM) or autopsy was performed, describing severe (AIS ≥ 3) injury patterns.

RESULTS

Overall, 222 fatalities suffered from blast injury, with most injuries affecting the upper and lower extremities (63.7% and 66.5%, respectively), followed by the head (57.1%) and the thorax (56.6%). The median number of injured body regions was 4 (interquartile range, 2-5). The most frequent injury combinations were the upper and lower extremities (51%), the upper extremities and the thorax (45%), and the lower extremities and the thorax (41%). In all, 47/222 (21.2%) fatalities had a documented autopsy or CT-PM report. Among the fatalities with CT-PM or autopsy, the head (63.8%) and the thorax (57.4%) were most frequently severely injured (AIS ≥ 3).

CONCLUSIONS

Among blast fatalities in the military setting, the extremities were most commonly injured. However, data suggest that the head and thorax are more likely to sustain severe blast injuries resulting in mortality. Blast injuries in this cohort were characterized by concomitant involvement of several regions. Development of protective gear to minimize the multisystem injuries inflicted by blast injuries is warranted and should be focused on distinct types and anatomical distribution of severe blast injuries as reported in this study.

LEVEL OF EVIDENCE

Level III, Retrospective analysis.

Soft-armor Vest Effectiveness and Intrathoracic Biomechanics in Rodents Exposed to Primary Blast

The biomechanics and efficacy of personal protective equipment in mitigating injuries from blast overpressure remain unclear. The objectives of this study were to define intrathoracic pressures in response to blast wave (BW) exposure and biomechanically evaluate a soft-armor vest (SA) at diminishing these perturbations. Male Sprague-Dawley rats were instrumented with pressure sensors in the thorax and were exposed laterally to multiple exposures ranging from 33 to 108 kPa BW with SA and without SA. There were significant increases in rise time, peak negative pressure, and negative impulse in the thoracic cavity compared to the BW. Esophageal measurements were increased to a greater extent when compared to the carotid and the BW for all parameters (except positive impulse, which decreased). SA minimally altered the pressure parameters and energy content. This study establishes the relationship of external blast flow conditions and intra-body biomechanical responses in the thoracic cavity of rodents with and without SA.

Beirut massive blast explosion: A unique injury pattern of the wounded population

INTRODUCTION

On August 4, 2020, a massive explosion of a warehouse holding 2,700 metric tons of ammonium nitrate took place in the port of Beirut, Lebanon. This incident, which is considered as one of the largest industrial disasters lead to the death of at least 220 people and more than 6000 injuries. Hospitals near the blast were damaged significantly which made it difficult to treat injured patients. The objective of this study is to report the epidemiology and characteristics of the injuries and their initial management that could be useful for healthcare workers and policymakers in case of a similar massive accident in the future.

MATERIALS AND METHODS

A retrospective study was conducted. All charts of patients admitted to the emergency room and outpatient clinics on the day of the blast and during the following 2 weeks were thoroughly reviewed. Due to initial chaos during triage, direct phone contact with patients was utilized in certain situations to confirm their identity or for further information. All acute injuries were recorded based on the region, severity, degree of emergency, initial and later management, type of injured organs, and surgical procedures.

RESULTS

A total of 159 patients presented to our facility. 153 patients presented to the ER on the same day of the blast. The mean age was 47.07 years and around 60% of the patients were males (n = 93). Most of the patients presented either from zone 1 (n = 67, 42%) or zone 3 (n = 68, 43%). The majority of injuries were secondary injuries due to glass (n = 131, 82.3%), with the head (34%) and upper extremities (31.2%) being most commonly affected. A total of 94 patients (62.6%) underwent a type of imaging and 64 patients (40.2%) had at least one surgery performed during their hospitalization in which 71% of the surgeries being related to the limbs.

CONCLUSION

This study demonstrated a unique injury pattern due to this type of blast. Injuries were mostly due to glass shrapnel. Contrary to bomb blasts, most injuries were located in the head and upper extremities rather than on the lower extremities.

Differences in quality-of-life scores across injury categories by mental health status among injured U.S. military service members and veterans

PURPOSE

Posttraumatic stress disorder (PTSD) and depression are strong predictors of poor health-related quality of life (HRQOL) among injured U.S. military service members (SMs). Patterns of HRQOL between injury categories and injury categories stratified by mental health (MH) symptoms have not been examined. Among deployment-injured SMs and veterans (n = 4353), we examined HRQOL and screening data for PTSD and/or depression within specific injury categories.

METHODS

Participants included those enrolled in the Wounded Warrior Recovery Project with complete data for HRQOL (SF-36) from June 2017 to May 2020. Injuries were categorized using the Barell Injury Diagnosis Matrix (Barell Matrix). Mean physical component summary (PCS) and mental component summary (MCS) scores were calculated for each injury category and stratified by the presence or absence of probable PTSD and/or depression.

RESULTS

The average follow-up time that participants were surveyed after injury was 10.7 years. Most participants were male, non-Hispanic White, served in the Army, and enlisted rank. Mechanism of injury for 77% was blast-related. Mean PCS and MCS scores across the entire sample were 43.6 (SD = 10.3) and 39.5 (SD = 13.3), respectively; 50% screened positive for depression and/or PTSD. PCS and MCS scores were significantly lower within each injury category among individuals with probable PTSD and/or depression than those without.

CONCLUSION

Among deployment-injured SMs, those with probable PTSD and/or depression reported significantly lower HRQOL within injury categories and HRQOL component (i.e., physical or mental) than those without. Findings are consistent with prior reports showing mental health symptoms to be strongly associated with lower HRQOL and suggest integration of mental health treatment into standard care practices to improve long-term HRQOL.

The Beirut ammonium nitrate blast: A multicenter study to assess injury characteristics and outcomes

BACKGROUND

Blasts incidents impose catastrophic aftermaths on populations regarding casualties, sustained injuries, and devastated infrastructure. Lebanon witnessed one of the largest nonnuclear chemical explosions in modern history-the August 2020 Beirut Port blast. This study assesses the mechanisms and characteristics of blast morbidity and mortality and examines severe injury predictors through the Injury Severity Score.

METHODS

A retrospective, multicenter cross-sectional study was conducted. Data of trauma patients presenting to five major acute-care hospitals in metropolitan Beirut up to 4 days following the blast were collected in a two-stage process from patient hospital chart review and follow-up phone calls.

RESULTS

A total of 791 patients with a mean age of 42 years were included. The mean distance from the blast was 2.4 km (SD, 1.9 km); 3.1% of victims were in the Beirut Port itself. The predominant mechanism of injury was being struck by an object (falling/projectile) (293 [37.0%]), and the most frequent site of injury was the head/face (209 [26.4%]). Injury severity was low for 548 patients (71.2%), moderate for 62 (8.1%), and severe/critical for 27 (3.5%). Twenty-one deaths (2.7%) were recorded. Significant serious injury predictors (Injury Severity Score, >15) were sustaining multiple injuries (odds ratio [OR], 2.62; p = 0.005); a fracture (OR, 5.78; p < 0.001); primary blast injuries, specifically a blast lung (OR, 18.82; p = 0.001), concussion (OR, 7.17; p < 0.001), and eye injury (OR, 8.51; p < 0.001); and secondary blast injuries, particularly penetrating injuries (OR, 9.93; p < 0.001) and traumatic amputations (OR, 13.49; p = 0.01). Twenty-five percent were admitted to the hospital, with 4.6% requiring the intensive care unit. At discharge, 25 patients (3.4%) had recorded neurologic disability.

CONCLUSION

Most injuries sustained by the blast victims were minor. Serious injuries were mostly linked to blast overpressure and projectile fragments. Understanding blast injuries characteristics, their severity, and management is vital to informing emergency services, disaster management strategies, hospital preparedness, and, consequently, improving patient outcomes.

LEVEL OF EVIDENCE

Prognostic and Epidemiologic; Level III.

Injuries in Underbody Blast Fatalities: Identification of Five Distinct Mechanisms of Head Injury

Previous research has shown that injuries to the head and neck were prevalent in 73% of all mounted fatalities of underbody blast. The mechanisms that cause such injuries to the central nervous system (CNS) are not yet known. The aim of this study was to identify the head and spinal injuries in fatalities due to underbody blast (UBB) and then develop hypotheses on the causative mechanisms. All U.K. military fatalities from UBB with an associated head injury that occurred during 2007-2013 in the Iraq and Afghanistan conflicts were identified retrospectively. Computed tomography post-mortems (CTPMs) were interrogated for injuries to the head, neck, and spine. All injuries were documented and classified using a radiology classification. Pearson's chi-square and Fisher's exact tests were used to show a relationship between variables and form a hypothesis for injury mechanisms. There were 50 fatalities from UBB with an associated head injury. Of these, 46 had complete CTPMs available for analysis. Chi-square and Fisher's exact tests showed a relationship between lateral ventricle blood and injuries to the abdomen and thorax. Five partially overlapping injury constellations were identified: 1.multiple-level spinal injury with skull fracture and brainstem injury, 2.peri-mesencephalic hemorrhage, 3.spinal and brainstem injury, 4.parenchymal contusions with injury to C0-C1, and 5.an "eggshell" pattern of fractures from direct impact. These injury constellations can now be used to propose injury mechanisms to develop mitigation strategies or clinical treatments.

Role of multi-layer tissue composition of musculoskeletal extremities for prediction of in vivo surface indentation response and layer deformations

Emergent mechanics of musculoskeletal extremities (surface indentation stiffness and tissue deformation characteristics) depend on the underlying composition and mechanics of each soft tissue layer (i.e. skin, fat, and muscle). Limited experimental studies have been performed to explore the layer specific relationships that contribute to the surface indentation response. The goal of this study was to examine through statistical modeling how the soft tissue architecture contributed to the aggregate mechanical surface response across 8 different sites of the upper and lower extremities. A publicly available dataset was used to examine the relationship of soft tissue thickness (fat and muscle) to bulk tissue surface compliance. Models required only initial tissue layer thicknesses, making them usable in the future with only a static ultrasound image. Two physics inspired models (series of linear springs), which allowed reduced statistical representations (combined locations and location specific), were explored to determine the best predictability of surface compliance and later individual layer deformations. When considering the predictability of the experimental surface compliance, the physics inspired combined locations model showed an improvement over the location specific model (percent difference of 25.4 +/- 27.9% and 29.7 +/- 31.8% for the combined locations and location specific models, respectively). While the statistical models presented in this study show that tissue compliance relies on the individual layer thicknesses, it is clear that there are other variables that need to be accounted for to improve the model. In addition, the individual layer deformations of fat and muscle tissues can be predicted reasonably well with the physics inspired models, however additional parameters may improve the robustness of the model outcomes, specifically in regard to capturing subject specificity.

Headache classification and automatic biomarker extraction from structural MRIs using deep learning

Data-driven machine-learning methods on neuroimaging (e.g. MRI) are of great interest for the investigation and classification of neurological diseases. However, traditional machine learning requires domain knowledge to delineate the brain regions first, followed by feature extraction from the regions. Compared with this semi-automated approach, recently developed deep learning methods have advantages since they do not require such prior knowledge; instead, deep learning methods can automatically find features that differentiate MRIs from different cohorts. In the present study, we developed a deep learning-based classification pipeline distinguishing brain MRIs of individuals with one of three types of headaches [migraine (n = 95), acute post-traumatic headache (n = 48) and persistent post-traumatic headache (n = 49)] from those of healthy controls (n = 532) and identified the brain regions that most contributed to each classification task. Our pipeline included: (i) data preprocessing; (ii) binary classification of healthy controls versus headache type using a 3D ResNet-18; and (iii) biomarker extraction from the trained 3D ResNet-18. During the classification at the second step of our pipeline, we resolved two common issues in deep learning methods, limited training data and imbalanced samples from different categories, by incorporating a large public data set and resampling among the headache cohorts. Our method achieved the following classification accuracies when tested on independent test sets: (i) migraine versus healthy controls-75% accuracy, 66.7% sensitivity and 83.3% specificity; (2) acute post-traumatic headache versus healthy controls-75% accuracy, 66.7% sensitivity and 83.3% specificity; and (3) persistent post-traumatic headache versus healthy controls-91.7% accuracy, 100% sensitivity and 83.3% specificity. The most significant biomarkers identified by the classifier for migraine were caudate, caudal anterior cingulate, superior frontal, thalamus and ventral diencephalon. For acute post-traumatic headache, lateral occipital, cuneus, lingual, pericalcarine and superior parietal regions were identified as most significant biomarkers. Finally, for persistent post-traumatic headache, the most significant biomarkers were cerebellum, middle temporal, inferior temporal, inferior parietal and superior parietal. In conclusion, our study shows that the deep learning methods can automatically detect aberrations in the brain regions associated with different headache types. It does not require any human knowledge as input which significantly reduces human effort. It uncovers the great potential of deep learning methods for classification and automatic extraction of brain imaging-based biomarkers for these headache types.

Blast Exposure Dysregulates Nighttime Melatonin Synthesis and Signaling in the Pineal Gland: A Potential Mechanism of Blast-Induced Sleep Disruptions

Blast-induced traumatic brain injury (bTBI) frequently results in sleep-wake disturbances. However, limited studies have investigated the molecular signaling mechanisms underlying these sleep disturbances, and potentially efficacious therapies are lacking. We investigated the levels of melatonin and genes involved in melatonin synthesis pathway in the pineal glands of Sprague Dawley rats exposed to single and tightly coupled repeated blasts during the night and daytime. Rats were exposed to single and tightly coupled repeated blasts using an advanced blast simulator. The plasma, cerebrospinal fluid (CSF), and pineal gland were collected at 6 h, 24 h, or 1 month postblast at two different time points: one during the day (1000 h) and one at night (2200 h). Differential expressions of genes involved in pineal melatonin synthesis were quantified using quantitative real-time polymerase chain reaction (qRT-PCR). Plasma and CSF melatonin levels were assessed using a commercial melatonin ELISA kit. The plasma and CSF melatonin levels showed statistically significant decreases at 6 h and 24 h in the blast-exposed rats euthanized in the night (in dim light), with no significant alterations noted in rats euthanized in the morning (daylight) at all three-time points. Blast-exposed rats showed statistically significant decreases in Tph1, Aanat, Asmt, and Mtnr1b mRNA levels, along with increased Tph2 mRNA, in the pineal gland samples collected at night at 6 h and 24 h. No significant changes in the mRNA levels of these genes were noted at 1 month. These findings imply that the melatonin circadian rhythm is disrupted following blast exposure, which may be a factor in the sleep disturbances that blast victims frequently experience.

Effects of orientation and distance of goats on blast lung injury characteristics on a plateau above 4500 m

PURPOSE

High explosives are used to produce blast waves to study their biological effects. The lungs are considered as the critical target organ in blast-effect studies. The degree of lung hemorrhaging is related to both the explosive power and the increased lung weight. We studied the characteristics of the biological effects from an air explosion of a thermobaric bomb in a high-altitude environment and the lethality and lung injury severity of goats in different orientation and distances.

METHODS

Goats were placed at 2.5, 3, 4, and 5 m from the explosion center and exposed them to an air blast at an altitude of 4700 m. A group of them standing oriented to the right side and the other group seated facing the explosion center vertically. The lung injuries were quantified according to the percentage of surface area contused, and using the pathologic severity scale of lung blast injury (PSSLBI) to score the 4 injury categories (slight, moderate, serious and severe) as 1, 2, 3, and 4, respectively. The lung coefficient (lung weight [g]/body weight [kg]) was the indicator of pulmonary edema and was related to lung injury severity. Blast overpressure data were collected using blast test devices placed at matching locations to represent loadings to goats. All statistical analyses were performed using SPSS, version 26.0, statistical software (SPSS, Inc., Chicago, IL, USA).

RESULTS

In total, 127 goats were involved in this study. Right-side-standing goats had a significantly higher mortality rate than those seated vertical-facing (p < 0.05). At the 2.5 m distance, the goat mortality was nearly 100%, whereas at 5 m, all the goats survived. Lung injuries of the right-side-standing goats were 1-2 grades more serious than those of seated goats at the same distances, the scores of PSSLBI were significantly higher than the seated vertical-facing goats (p < 0.05). The lung coefficient of the right-side-standing goats were significantly higher than those of seated vertical-facing (p < 0.05). Mortality, PSSLBI, and the lung coefficient results indicated that the right-side-standing goats experienced severer injuries than the seated vertical-facing goats, and the injuries were lessened as the distance increased. The blast overpressure was consistent with these results.

CONCLUSION

The main killing factors of the thermobaric bomb in the high-altitude environment were blast overpressure, blast wind propulsions and burn. The orientation and distances of the goats significantly affected the blast injury severity. These results may provide a research basis for diagnosing, treating and protecting against injuries from thermobaric explosions.

Template models for simulation of surface manipulation of musculoskeletal extremities

Capturing the surface mechanics of musculoskeletal extremities would enhance the realism of life-like mechanics imposed on the limbs within surgical simulations haptics. Other fields that rely on surface manipulation, such as garment or prosthetic design, would also benefit from characterization of tissue surface mechanics. Eight homogeneous tissue models were developed for the upper and lower legs and arms of two donors. Ultrasound indentation data was used to drive an inverse finite element analysis for individualized determination of region-specific material coefficients for the lumped tissue. A novel calibration strategy was implemented by using a ratio based adjustment of tissue properties from linear regression of model predicted and experimental responses. This strategy reduced requirement of simulations to an average of under four iterations. These free and open-source specimen-specific models can serve as templates for simulations focused on mechanical manipulations of limb surfaces.

Long-Term Effects of Repeated Blast Exposure in United States Special Operations Forces Personnel: A Pilot Study Protocol

Emerging evidence suggests that repeated blast exposure (RBE) is associated with brain injury in military personnel. United States (U.S.) Special Operations Forces (SOF) personnel experience high rates of blast exposure during training and combat, but the effects of low-level RBE on brain structure and function in SOF have not been comprehensively characterized. Further, the pathophysiological link between RBE-related brain injuries and cognitive, behavioral, and physical symptoms has not been fully elucidated. We present a protocol for an observational pilot study, Long-Term Effects of Repeated Blast Exposure in U.S. SOF Personnel (ReBlast). In this exploratory study, 30 active-duty SOF personnel with RBE will participate in a comprehensive evaluation of: 1) brain network structure and function using Connectome magnetic resonance imaging (MRI) and 7 Tesla MRI; 2) neuroinflammation and tau deposition using positron emission tomography; 3) blood proteomics and metabolomics; 4) behavioral and physical symptoms using self-report measures; and 5) cognition using a battery of conventional and digitized assessments designed to detect subtle deficits in otherwise high-performing individuals. We will identify clinical, neuroimaging, and blood-based phenotypes that are associated with level of RBE, as measured by the Generalized Blast Exposure Value. Candidate biomarkers of RBE-related brain injury will inform the design of a subsequent study that will test a diagnostic assessment battery for detecting RBE-related brain injury. Ultimately, we anticipate that the ReBlast study will facilitate the development of interventions to optimize the brain health, quality of life, and battle readiness of U.S. SOF personnel.

Combat injury profiles among U.S. military personnel who survived serious wounds in Iraq and Afghanistan: A latent class analysis

Background

The U.S. military conflicts in Iraq and Afghanistan had the most casualties since Vietnam with more than 53,000 wounded in action. Novel injury mechanisms, such as improvised explosive devices, and higher rates of survivability compared with previous wars led to a new pattern of combat injuries. The purpose of the present study was to use latent class analysis (LCA) to identify combat injury profiles among U.S. military personnel who survived serious wounds.

Methods

A total of 5,227 combat casualty events with an Injury Severity Score (ISS) of 9 or greater that occurred in Iraq and Afghanistan from December 2002 to July 2019 were identified from the Expeditionary Medical Encounter Database for analysis. The Barell Injury Diagnosis Matrix was used to classify injuries into binary variables by site and type of injury. LCA was employed to identify injury profiles that accounted for co-occurring injuries. Injury profiles were described and compared by demographic, operational, and injury-specific variables.

Results

Seven injury profiles were identified and defined as: (1) open wounds (18.8%), (2) Type 1 traumatic brain injury (TBI)/facial injuries (14.2%), (3) disseminated injuries (6.8%), (4) Type 2 TBI (15.4%), (5) lower extremity injuries (19.8%), (6) burns (7.4%), and (7) chest and/or abdominal injuries (17.7%). Profiles differed by service branch, combat location, year of injury, injury mechanism, combat posture at the time of injury, and ISS.

Conclusion

LCA identified seven distinct and interpretable injury profiles among U.S. military personnel who survived serious combat injuries in Iraq or Afghanistan. These findings may be of interest to military medical planners as resource needs are evaluated and projected for future conflicts, and medical professionals involved in the rehabilitation of wounded service members.

A role for insulin-like growth factor-1 in hippocampal plasticity following traumatic brain injury

Traumatic brain injury (TBI) initiates a constellation of secondary injury cascades, leading to neuronal damage and dysfunction that is often beyond the scope of endogenous repair mechanisms. Cognitive deficits are among the most persistent morbidities resulting from TBI, necessitating a greater understanding of mechanisms of posttraumatic hippocampal damage and neuroplasticity and identification of therapies that improve recovery by enhancing repair pathways. Focusing here on hippocampal neuropathology associated with contusion-type TBIs, the impact of brain trauma on synaptic structure and function and the process of adult neurogenesis is discussed, reviewing initial patterns of damage as well as evidence for spontaneous recovery. A case is made that insulin-like growth factor-1 (IGF-1), a growth-promoting peptide synthesized in both the brain and the periphery, is well suited to augment neuroplasticity in the injured brain. Essential during brain development, multiple lines of evidence delineate roles in the adult brain for IGF-1 in the maintenance of synapses, regulation of neurotransmission, and modulation of forms of synaptic plasticity such as long-term potentiation. Further, IGF-1 enhances adult hippocampal neurogenesis though effects on proliferation and neuronal differentiation of neural progenitor cells and on dendritic growth of newly born neurons. Post-injury administration of IGF-1 has been effective in rodent models of TBI in improving learning and memory, attenuating death of mature hippocampal neurons and promoting neurogenesis, providing critical proof-of-concept data. More studies are needed to explore the effects of IGF-1-based therapies on synaptogenesis and synaptic plasticity following TBI and to optimize strategies in order to stimulate only appropriate, functional neuroplasticity.

The Role of the Inflammatory Response in Mediating Functional Recovery Following Composite Tissue Injuries

Composite tissue injuries (CTI) are common among US Military Service members during combat operations, and carry a high potential of morbidity. Furthermore, CTI are often complicated due to an altered wound healing response, resulting in part from a dysregulation of the innate and adaptive immune responses. Unlike normal wound healing, in CTI, disruptions occur in innate immune responses, altering neutrophil functions, macrophage activation and polarization, further impacting the functions of T regulatory cells. Additionally, the biological underpinnings of these unfavorable wound healing conditions are multifactorial, including various processes, such as: ischemia, hypoxia, low nutrient levels, and altered cell metabolic pathways, among others, all of which are thought to trigger anergy in immune cells and destabilize adaptive immune responses. As a result, impaired wound healing is common in CTI. Herein, we review the altered innate and adaptive immune cells and their metabolic status and responses following CTI, and discuss the role a multi-pronged immunomodulatory approach may play in facilitating improved outcomes for afflicted patients.

Wartime upper-extremity injuries in the Sahelian strip: Experience from a French Forward Surgical Team deployed in Mali

This study aimed to analyze upper-extremity combat-related injuries (CRIs) and non-combat-related injuries (NCRIs) treated in the French Forward Surgical Team currently deployed in Gao, Mali. A retrospective study was conducted using the French Military Health Service OpEX surgical database from February 2013 to March 2020. All patients operated on for upper-extremity injury were included: 224 patients, with a mean age of 28.15 years, for 249 upper-extremity injuries. Seventy-six (33.9%) sustained CRIs and 148 (66.1%) NCRIs. Multiple upper-extremity injuries and associated injuries were significantly more common in the CRI group. The majority of NCRIs involved the hand. Debridement and wound care was the most common procedure in both groups. External fixation and fasciotomy were significantly more frequent in the CRI group, and internal fracture fixation in the NCRI group. The overall number of procedures was significantly higher in the CRI group. Due to the high frequency of upper-extremity injury in current theaters of operations, deployed orthopedic surgeons should be trained in basic hand surgery so as to optimally manage both CRIs and NCRIs.

Mental and physical health, and long-term quality of life among service members injured on deployment

Background

More than 52,000 casualties have been documented in post-9/11 conflicts. Service members with extremity injuries (EIs) or traumatic brain injury (TBI) may be at particular risk for long-term deficits in mental and physical health functioning compared with service members with other injuries.

Methods

The present study combined medical records with patient reports of mental health and health-related quality of life (HRQOL) for 2,537 service members injured in overseas contingency operations who participated in the Wounded Warrior Recovery Project. Combined parallel-serial mediation models were tested to examine the pathways through which injury is related to mental and physical health conditions, and long-term HRQOL.

Results

Results revealed that injury was indirectly related to long-term HRQOL via its associations with physical health complications and mental health symptoms. Relative to TBI, EI was associated with a higher likelihood for a postinjury diagnosis for a musculoskeletal condition, which were related to lower levels of later posttraumatic stress disorder (PTSD) symptoms, and higher levels of physical and mental HRQOL. Similarly, EI was related to a lower likelihood for a postinjury PTSD diagnosis, and lower levels of subsequent PTSD symptoms, and therefore higher physical and mental HRQOL relative to those with TBI. Despite this, the prevalence of probable PTSD among those with EI was high (35%). Implications for intervention, rehabilitation, and future research are discussed.

Severe Calcaneus Injury Probability Curves Due to Under-Body Blast

The lower extremity is the most frequently injured body region to mounted soldiers during underbody blast (UBB) events. UBB events often produce large deformations of the floor and subsequent acceleration of the lower limb that are not sufficiently mitigated by the combat boot, leaving the calcaneus bone vulnerable to injury. Biomechanical experiments simulating UBB loading scenarios were conducted in a laboratory environment using isolated postmortem human subject (PMHS) leg components. Each leg component was tested twice: one sub-injurious test followed by a injury-targeted test. This enabled the use of interval censoring for each specimen in the survival statistical analysis to generate the human injury probability curves (HIPCs). Foot contact forces were measured in both the hindfoot and forefoot. Strains and acoustic emission signals at the calcaneus and distal tibia were utilized to determine injury timing. The footplate velocities of the injury tests ranged 8-13 m/s with time-to-peak velocity of 1.8-2.5 ms while the velocities of non-injury tests ranged from 4 to 6 m/s with the same time-to-peak. The majority of the injuries were severe calcaneus fractures (Sanders III-IV). Secondary injuries included fractures to the distal tibia, talus, cuboid and cuneiform. These injury outcomes were found to be consistent with those reported in UBB injury literature. The HIPCs for the severe calcaneus fracture were developed using the vertical heel contact force as the injury correlation measure through survival analysis statistical method in the form of lognormal function. This work represents the first set of HIPCs dedicated to the severe calcaneus fracture using the biomechanical force measurement closest to the injury location. This injury probability curve will enable biomechanical response validation of computational models, development of ATD injury assessment reference curve, and injury prediction capability for computational models or ATDs in the UBB environment.

Imaging findings in patients after the bomb explosion in Somalia on December 28, 2019

INTRODUCTION

This study aimed to present the radiological findings of injuries in victims as a result of a suicide bombing in Mogadishu, Somalia.

METHODS

Of the 82 injured cases admitted to the emergency department within the first six hours after the explosion, those who were radiologically evaluated were included in this retrospective and descriptive study. To analyze and identify the distribution of primary, secondary, and tertiary injuries, they were classified according to the body areas as head-neck, thorax, abdominopelvic, extremity, and vertebra.

RESULTS

The mean age (mean ± SD) of 63 patients included in the study was 28.6 ± 10.2 years. Twenty-four (38.1%) of the injured patients were female and 39 (61.9%) were male. Secondary blast injury was the most common type of injury in the study group with a rate of 39/63 (62%). The total number of bomb fragments was 235, of which 113 (47.8%) were seen in the head and neck region, followed by 86 (36.5%) in the extremities. There were 10 patients (15.9%) with lung injury and 13 (20.6%) with tympanic membrane perforation due to the primary blast mechanism.

CONCLUSION

Radiological imaging plays an important role in identifying specific findings and patterns of explosive injuries. Therefore, we consider that patients with stable hemodynamics should be radiologically examined for a fast and accurate diagnosis or treatment.

A Focus on Non-Amputation Combat Extremity Injury: 2001-2018

INTRODUCTION

Extremity injuries have comprised the majority of battlefield injuries in modern U.S. conflicts since World War II. Most reports have focused on serious injuries only and, to date, no reports have described the full extent of combat extremity injuries, from mild to severe, resulting from post-9/11 conflicts. This study aims to identify and characterize the full spectrum of non-amputation combat-related extremity injury and extend the findings of previous reports.

METHODS

The Expeditionary Medical Encounter Database was queried for all extremity injured service members (SMs) deployed in support of post-9/11 conflicts through July 2018. Only injuries incurred during combat operations were included in this report. Major amputations were excluded as well as SMs killed in action or who died of wounds. Extremity injuries were categorized by body region, nature of injury, and severity. Demographics and injury event characteristics are also presented.

RESULTS

A total of 17,629 SMs sustained 42,740 extremity injuries during 18,004 separate injury events. The highest number of SMs were injured in 2004 (n = 3,553), 2007 (n = 2,244), and 2011 (n = 2,023). Injured SMs were mostly young (78% under 30 years), male (97%), junior- to mid-level enlisted (89%), in the Army (69%) or Marine Corps (28%), active duty (84%), serving as infantry and gun crew (59%), and injured in support of Operation Iraqi Freedom (60%). Blast weaponry was responsible for 75% of extremity injuries. Injuries were similarly distributed between the lower (52%) and upper (48%) extremities. The most common sites of lower extremity injury were the lower leg/ankle complex (40%) and thigh (26%). The most common upper extremities sites were the shoulder and upper arms (37%), and the hand, wrist, and fingers (33%). Nearly half (48%) of all extremity injuries were open wounds (48%), followed by fractures (20%) and contusions/superficial injuries (16%). SMs sustained an average of 2.4 extremity injuries per event and 56% of injuries were considered mild, with a median Injury Severity Score (ISS) of 3.

CONCLUSION

This study is the first publication to capture, review, and characterize the full range, from mild to severe, of non-amputation combat-related extremity injuries resulting from post-9/11 conflicts. The high prevalence of extremity injury, particularly in such a young population, and associated short- and long-term health outcomes, will impact military health care systems for decades to come.

Symptom profiles following combat injury and long-term quality of life: a latent class analysis

PURPOSE

The purpose of this study was to identify symptom profiles among U.S. military personnel within 1 year after combat injury and assess the relationship between the symptom profiles and long-term quality of life (QoL).

METHODS

The study sample consisted of 885 military personnel from the Expeditionary Medical Encounter Database who completed (1) a Post-Deployment Health Assessment (PDHA) within 1 year following combat injury in Iraq or Afghanistan, and (2) a survey for the Wounded Warrior Recovery Project (WWRP), a longitudinal study tracking patient-reported outcomes (e.g., QoL) in injured military personnel. Fifteen self-reported symptoms from the PDHA were assessed using latent class analysis to develop symptom profiles. Multivariable linear regression assessed the predictive effect of symptom profiles on QoL using the physical (PCS) and mental (MCS) component summary scores from the 36-Item Short Form Survey included in the WWRP. Time between PDHA and WWRP survey ranged from 4.3 to 10.5 years (M = 6.6, SD = 1.3).

RESULTS

Five distinct symptom profiles were identified: low morbidity (50.4%), multimorbidity (15.6%), musculoskeletal (14.0%), psycho-cognitive (11.1%), and auditory (8.9%). Relative to low morbidity, the multimorbidity (β =  - 5.45, p < 0.001) and musculoskeletal (β =  - 4.23, p < 0.001) profiles were associated with lower PCS, while the multimorbidity (β =  - 4.25, p = 0.002) and psycho-cognitive (β =  - 3.02, p = 0.042) profiles were associated with lower MCS.

CONCLUSION

Multimorbidity, musculoskeletal, and psycho-cognitive symptom profiles were the strongest predictors of lower QoL. These profiles can be employed during screening to identify at-risk service members and assist with long-term clinical planning, while factoring in patient-specific impairments and preferences.

Fast-Running Tools for Personalized Monitoring of Blast Exposure in Military Training and Operations

INTRODUCTION

During training and combat operations, military personnel may be exposed to repetitive low-level blast while using explosives to gain entry or by firing heavy weapon systems such as recoilless weapons and high-caliber sniper rifles. This repeated exposure, even within allowable limits, has been associated with cognitive deficits similar to that of accidental and sports concussion such as delayed verbal memory, visual-spatial memory, and executive function. This article presents a novel framework for accurate calculation of the human body blast exposure in military heavy weapon training scenarios using data from the free-field and warfighter wearable pressure sensors.

MATERIALS AND METHODS

The CoBi human body model generator tools were used to reconstruct multiple training scenes with different weapon systems. The CoBi Blast tools were used to develop the weapon signature and estimate blast overpressure exposure. The authors have used data from the free-field and wearable pressure sensors to evaluate the framework.

RESULTS

Carl-Gustav and 0.50 caliber sniper training scenarios were used to demonstrate and validate the developed framework. These simulations can calculate spatially and temporally resolved blast loads on the whole human body and on specific organs vulnerable to blast loads, such as head, face, and lungs.

CONCLUSIONS

This framework has numerous advantages including easier model setup and shorter simulation times. The framework is an important step towards developing an advanced field-applicable technology to monitor low-level blast exposure during heavy weapon military training and combat scenarios.

Clinic Use at the Departments of Defense and Veterans Affairs Following Combat Related Amputations

INTRODUCTION

Little population-based research has described the transition from Department of Defense (DoD) to Department of Veterans Affairs (VA) healthcare following combat related amputations. The objectives were to describe (1) to what extent patients used either DoD only facilities, both DoD and VA facilities, or VA only facilities during the first 5 years postinjury, (2) which specific clinics were used and (3) clinic use among patients with different levels of amputation (upper versus lower), and among patients with early or late amputation.

MATERIALS AND METHODS

This was a retrospective analysis of health data extracted from the expeditionary medical encounter database (EMED) and national DoD and VA databases. Patients were 649 US service members who sustained a single major limb amputation following injuries in the Iraq and Afghanistan conflicts, 2001-2008. We compared yearly DoD and VA clinic use by patient groups with different levels of amputation (upper limb: above versus below elbow or lower limb: above versus below knee), different timing of amputation (early: within 90 days postinjury versus late: more than 90 days postinjury), military component (Active Duty versus National Guard/Reserve) and race (White versus Black). For all groups, we calculated the percentage of patients using: (1) DoD only, (2) both DoD and VA or 3) VA only clinics during each of postinjury years 1 through 5. We also calculated the percentage of patients who used specific clinics (e.g., social work, prosthetics, mental health) during each postinjury year.

RESULTS

During postinjury year 1, over 98% of patients used DoD only or both DoD and VA clinics. Most individuals (70% to 78%) used both DoD and VA clinics during postinjury year 1. Use of VA only clinics increased gradually between postinjury year 2 (15% to 30% of patient groups) and year 5 (75% to 88%). This gradual transition to use of VA only clinics was seen consistently across patient groups with different anatomical levels or timing of amputation, military component or race. Patients with lower levels of amputation (versus higher levels) and individuals with early amputations (versus late) transitioned earlier to VA only care. Overall, clinic use was high as 91% to 100% of all patient groups used one or more clinics (DoD or VA) during each of the first 5 years. For specific clinics, most patients used DoD facilities related to rehabilitation (physical therapy, prosthetics) or transitional care (social work) particularly during postinjury year 1. Use of most VA clinics studied (social work, primary care, prosthetics, mental health) showed a modest increase primarily after postinjury year 1 and remained stable through postinjury year 5. The results indicated apparent underuse of psychiatric/mental health and prosthetics between postinjury year 1 and 2.

CONCLUSIONS

The present study indicated a gradual transition from DoD to VA only healthcare which extended across 5 years following combat related amputations. Patients with lower levels of amputation or early amputation generally transitioned earlier to VA only healthcare. These results can inform medical planning to support a timely and clinically effective transition from DoD to VA healthcare.

The clinical utility of proton magnetic resonance spectroscopy in traumatic brain injury: recommendations from the ENIGMA MRS working group

Proton (1H) magnetic resonance spectroscopy provides a non-invasive and quantitative measure of brain metabolites. Traumatic brain injury impacts cerebral metabolism and a number of research groups have successfully used this technique as a biomarker of injury and/or outcome in both pediatric and adult TBI populations. However, this technique is underutilized, with studies being performed primarily at centers with access to MR research support. In this paper we present a technical introduction to the acquisition and analysis of in vivo 1H magnetic resonance spectroscopy and review 1H magnetic resonance spectroscopy findings in different injury populations. In addition, we propose a basic 1H magnetic resonance spectroscopy data acquisition scheme (Supplemental Information) that can be added to any imaging protocol, regardless of clinical magnetic resonance platform. We outline a number of considerations for study design as a way of encouraging the use of 1H magnetic resonance spectroscopy in the study of traumatic brain injury, as well as recommendations to improve data harmonization across groups already using this technique.

How Common Are Civilian Blast Injuries in the National Trauma Databank, and What Are the Most Common Mechanisms and Characteristics of Associated Injuries?

BACKGROUND

Recent military conflicts have produced substantial improvements in the care of service members who experience blast injuries. As conflicts draw down, it is important to preserve and improve skills gained in combat. It is unknown whether civilian blast injuries can serve as a surrogate for military blast trauma. To guide further research, it is crucial to understand the volume, severity, and distribution of civilian blast injury in the civilian population.

QUESTIONS/PURPOSES

(1) What proportion of US trauma admissions are a result of blast injury? (2) What are the common mechanisms, and what is the demographic breakdown of civilian patients presenting to trauma centers after blast injuries? (3) What is the severity, and what are the characteristics of injuries sustained by civilian patients after blast injuries?

METHODS

We queried the American College of Surgeons National Trauma Databank (NTDB), a national aggregation of trauma registry data which captures robust mechanism of injury and wounding pattern information, for any patient admitted for trauma and an initial mechanism of injury corresponding to a predefined list of ICD-9 and ICD-10 external cause of injury codes related to blast injuries and reported as a proportion of all trauma-related admissions. Mechanisms were categorized into similar groups, and data were collected regarding demographics as well as location and intentionality of blast (that is, unintentional, the result of assault, or self-inflicted). Patient injuries were characterized by ICD-9 or ICD-10 diagnosis codes and sorted according to the body area affected and severity of injury, measured via the Injury Severity Score (ISS). The ISS is a measure of trauma severity, with scores ranging from 1 to 75 points based on injury severity, which is calculated according to injury scores in six separate body domains (head or neck, face, chest, abdomen or pelvis, extremities, external). A score of 1 represents a minor trauma to one region, while a score of 75 indicates injuries deemed nonsurvivable in one or more domains. Data were limited to trauma admissions in 2016.

RESULTS

Patients injured by blast mechanisms represented 0.3% (2682 of 968,843) of patients in NTDB-participating trauma centers who were treated after a blast injury in the year 2016; 86% (2315 of 2682) of these patients were men, and the mean ± SD age was 38 ± 21 years. Blast injuries most commonly occurred after detonation of fireworks (29% [773 of 2682]) or explosion of gas or pressurized containers (27% [732 of 2682]). The most commonly injured area of the body was the upper extremity (33% [894 of 2682]), followed by the face (28% [747 of 2682]), lower extremity (11% [285 of 2682]), thorax (10% [280 of 2682]), and head (10% [259 of 2682]). Fifty-eight percent (1564 of 2682) of patients had at least one burn injury. A total of 2% (51 of 2682) of the injuries were fatal, with a mean ISS score of 6 ± 8; 23% (608 of 2682) of patients presented with injuries classified as severe (ISS > 8).

CONCLUSION

Civilian blast-associated injuries are not common, but they can be severe, and in many (though not all) respects they seem similar to those described in published case series of military blast victims. Key differences include age and gender (civilian injuries more commonly involve women and older patients than do those in military studies). The potential of civilian blast patient care as a surrogate for study and clinical experience for military surgeons in the interwar period-as recommended by the National Academies of Sciences, Engineering, and Medicine report-is supported by our preliminary results. Future interventions or training programs would likely need to rely on multisite or targeted partnerships to encounter appropriate numbers of patients with blast injuries.

LEVEL OF EVIDENCE

Level IV, prognostic study.

The Relationship Between Severe Visual Acuity Loss, Traumatic Brain Injuries, and Ocular Injuries in American Service Members From 2001 to 2015

INTRODUCTION

Although traumatic brain injury (TBI) is known to cause many visual problems, the correlation between the extent of severe visual acuity loss (SVAL) and severity of TBI has not been widely explored. In this retrospective analysis, combined information from Department of Defense (DoD)/Veterans Affairs ocular injury and TBI repositories were used to evaluate the relationship between chronic SVAL, TBI, ocular injuries, and associated ocular sequelae for U.S. service members serving between 2001 and 2015.

MATERIALS AND METHODS

The Defense and Veterans Eye Injury and Vision Registry (DVEIVR) is an initiative led by the DoD and Veterans Affairs that consists of clinical and related data for service members serving in theater since 2001. The Defense and Veterans Brain Injury Center (DVBIC) is the DoD's office for tracking TBI data in the military and maintains data on active-duty service members with a TBI diagnosis since 2000. Longitudinal data from these 2 resources for encounters between February 2001 and October 2015 were analyzed to understand the relation between SVAL, and TBI while adjusting for ocular covariates such as open globe injury (OGI), disorders of the anterior segment and disorders of the posterior segment in a logistic regression model. TBI cases in DVEIVR were identified using DVBIC data and classified according to International Statistical Classification of Diseases criteria established by DVBIC. Head trauma and other open head wounds (OOHW) were also included. SVAL cases in DVEIVR were identified using both International Statistical Classification of Diseases criteria for blindness and low vision as well as visual acuity test data recorded in DVEIVR.

RESULTS

Data for a total of 25,193 unique patients with 88,996 encounters were recorded in DVEIVR from February, 2001 to November, 2015. Of these, 7,217 TBI and 1,367 low vision cases were identified, with 638 patients experiencing both. In a full logistic model, neither UTBI nor differentiated TBI (DTBI, ie, mild, moderate, severe, penetrating, or unclassified) were significant risk factors for SVAL although ocular injuries (disorders of the anterior segment, disorders of the posterior segment, and OGI) and OOHW were significant.

CONCLUSION

Any direct injury to the eye or head risks SVAL but the location and severity will modify that risk. After adjusting for OGIs, OOHW and their sequelae, TBI was found to not be a significant risk factor for SVAL in patients recorded in DVEIVR. Further research is needed to explore whether TBI is associated with more moderate levels of vision acuity loss.

Headache Characteristics and Psychological Factors Associated with Functional Impairment in Individuals with Persistent Posttraumatic Headache

OBJECTIVE

Persistent posttraumatic headache (PPTH), one of the most common symptoms following mild traumatic brain injury, is often associated with substantial functional disability. The objective of this study was to assess the contribution of demographics, headache characteristics, and psychological symptoms to disability associated with PPTH.

METHODS

Participants completed the State-Trait Anxiety Inventory (STAI), the Beck Depression Inventory (BDI), the Pain Catastrophizing Scale (PCS), and the Migraine Disability Assessment (MIDAS) questionnaire. Two linear regression models were formulated to interrogate the relationships between 1) demographics and headache characteristics with the MIDAS questionnaire and 2) demographics, headache characteristics, and psychological symptoms with the MIDAS questionnaire. A two-way stepwise regression using the Akaike information criterion was performed to find a parsimonious model describing the relationships between demographics, headache characteristics, and psychological measures with the MIDAS questionnaire.

RESULTS

Participants included 58 patients with PPTH and 39 healthy controls (HCs). The median MIDAS score among those with PPTH was 48.0 (first quartile [1Q] = 20.0, third quartile [3Q] = 92.0), indicative of severe disability. Compared with the HCs, those with PPTH had higher scores on the BDI, STAI, and PCS. Older age predicted lower MIDAS scores (age: B=-0.11, P<0.01), whereas higher headache frequency, greater headache intensity, and higher trait anxiety scores predicted higher MIDAS scores in individuals with PPTH (headache frequency: B=0.07, P<0.001; headache intensity: B=0.51, P=0.04; trait anxiety score: B=1.11, P=0.01).

CONCLUSIONS

Individuals with PPTH had substantial psychological symptoms and headache-related disability. Disability was partially explained by age, headache frequency and intensity, and trait anxiety. Holistic management of patients with PPTH to address headaches and psychological symptoms might reduce headache-associated disability.

Bomb blast: imaging findings, treatment and clinical course of extremity traumas

Background

To describe the severity and types of blast-related extremity injuries and the presence of accompanying vascular injuries (VI) and amputation, and to identify the associated factors affecting the treatment management and clinical course.

Methods

The study included 101 patients with extremity injuries caused by a bomb explosion. The radiographs and computed tomography angiographies of the patients were evaluated in terms of injury patterns, presence of penetrating fragments and fractures, and localization (upper or lower extremity) and type (open or closed) of injury. The Gustilo-Anderson classification was used for open fractures. According to their severity, open fractures classified as types 1 and 2 were included in Group 1 and those classified as type 3A, 3B and 3C in Group 2.

Results

As a result of blast exposure, 101 (57.7%) patients had extremity injuries, of which 76 (75.2%) presented with at least one fracture. Of the total of 103 fractures, nine (8.8%) were closed and 94 (91.2%) were open. Thirty-eight (40.4%) of the open fractures were located in the upper extremities, and 56 (59.6%) in the lower extremities and pelvis. Open fractures were most frequently localized in the femur (n = 20; 21.2%), followed by the tibia (n = 18; 19.1%). The majority of patients with open fractures were in Group 1 (71.4%). The duration of hospital stay was longer in Group 2 (12.1 ± 5.8 vs. 6.3 ± 6.7 days, p <  0.0001, respectively). Mortality among patients in Group 2 (45.0%) was significantly higher than in Group 1 (8.0%) (p <  0.0001). Similarly, the injury severity score (ISS) was higher in Group 2 (median 20 vs. 9, p <  0.0001). VI was present in 13 (12.9%) of all patients, and amputation in seven (7.9%).

Conclusion

The presence of severe open fractures, VI, and high ISS score can be considered as important factors that increase morbidity and mortality. In extremity traumas, through the secondary blast mechanism, contaminated-fragmented tissue injuries occur. Therefore, we believe that it will be beneficial to apply damage control surgery in places with low socioeconomic level and poor hygienic conditions.

Estimating Repeat Traumatic Brain Injury in the U.S. Military, 2015-2017

INTRODUCTION

Traumatic brain injury (TBI) is a significant health issue among deployed and non-deployed U.S. military service members (SMs). Since 2000, an estimated 413,858 SMs have been diagnosed with at least one TBI. Due to the difficulty in distinguishing new incident TBIs from follow-up TBI-related medical encounters in the Military Health System (MHS), the official TBI case definition also includes an incidence rule considering an individual an incident case only once per lifetime. We sought to examine patterns in medical records of SMs with at least one TBI encounter, in an effort to identify repeat TBIs in individual SMs and to estimate the incidence of repeat TBIs within the study cohort as a whole.

MATERIALS AND METHODS

Using the official DoD TBI case definition, we obtained a list of SMs who sustained their first active duty TBI between October 1, 2015, and September 30, 2017. We identified the SM's diagnosing encounter (index TBI). Subsequently, we identified patterns associated with diagnosing medical encounters, as opposed to encounters associated with follow-up TBI care. We flagged external cause of injury records and the presence of TBI-related symptom codes at the diagnosing encounter. Traumatic brain injury-related symptoms included memory issues, alteration of cognition, hearing loss, vertigo, headache, anxiety, depression, emotional lability, weakness, insomnia, and vision disturbance. Data discovery results were shared with a group of clinicians at the Defense and Veterans Brain Injury Center, and the list of variables was further refined based on clinical expertise. Subsequently, we conducted stepwise logistic regression, and best fitting model was used to create a probability score to be applied to all TBI-related medical encounters. To validate the accuracy of the model-derived probability score, a stratified random sample of medical records was reviewed by trained clinician. At the 0.5 probability cutoff point, the model had an area under the curve of 0.69. We applied the final model portability scores to all identified TBI encounters to estimate the incidence of repeat TBI within the cohort.

RESULTS

Between October 1, 2015, and September 30, 2017, we identified 36,440 SMs and their first lifetime TBI encounter. Study follow-up period was 2 years. Predictors of repeat TBI (rTBI) encounters included the presence of TBI diagnosis extender codes "A" (odds ratio [OR] = 4.67, 95% CI 2.15-10.12); W and V series codes (OR = 4.05, 95% CI 2.05-7.95 and OR = 2.86, 95% CI 1.40-5.83, respectively); patient's disposition at home/quarters; and admission or immediate referral (OR = 3.67, 95% CI 1.79-7.51). Number of diagnosis codes in patient's medical record was inversely associated with a repeat TBI encounter (OR = 0.84, 95% CI 0.76-0.96). Applying model-derived probability score onto identified medical records, we estimate that 804 unique SMs sustained an rTBI during the follow-up period, yielding a rate of 260 rTBIs per 10,000 person-years or approximately 2.32% of SMs annually.

CONCLUSION

Probability scores based on statistical modeling can provide reasonable estimates of repeat incidences of TBI using medical billing data when formerly only the first TBI was thought to be measurable. With 100% sensitivity and 69% specificity, application of these models can inform estimates of repeat TBI across the MHS. This effort shows initial success if estimating repeat TBI, and further modeling work is encouraged to increase the predictive characteristics of the models as these efforts show promise in estimating repeat TBI across the MHS.

Estimates of Long-Term Disability Among US Service Members With Traumatic Brain Injuries

BACKGROUND

Traumatic brain injury (TBI) is a significant health issue in the US military. The purpose of this study was to estimate the probability of long-term disability among hospitalized service members (SMs) with TBIs, using the South Carolina Traumatic Brain Injury and Follow-up Registry (SCTBIFR) model developed on civilian hospitalized patients.

METHODS

We identified military patients in military or civilian hospitals or theater level 3 to 5 military treatment facilities (MTFs) whose first TBI occurred between October 1, 2013, and September 30, 2015. TBI-related disability at 1-year post-hospital discharge was estimated using regression coefficients from the SCTBIFR.

RESULTS

Among the identified 4877 SMs, an estimated 65.6% of SMs with severe TBI, 56.2% with penetrating TBI, 31.4% with moderate TBI, and 12.0% with mild TBI are predicted to develop long-term disability. TBI patients identified at theater level 4 and 5 MTFs had an average long-term disability rate of 56.9% and 61.1%, respectively. In total, we estimate that 25.2% of all SMs hospitalized with TBI will develop long-term disability.

CONCLUSION

Applying SCTBIFR long-term probability estimates to US SMs with TBIs provides useful disability estimates to inform providers and health systems on the likelihood that particular subgroups of TBI patients will require continued support and long-term care.

The relationship between self-reported physical functioning, mental health, and quality of life in Service members after combat-related lower extremity amputation

PURPOSE

Service members with amputations experience numerous challenges, yet few studies have examined patient-reported outcomes, including physical functional status, mental-health screening status, and quality of life (QOL) or the relationship between these outcomes.

MATERIALS AND METHODS

Service members with combat-related lower extremity amputations (N = 82) and participants in the Wounded Warrior Recovery Project were included. Patient-reported outcomes of physical functional status, posttraumatic stress disorder (PTSD), depression screening status, and QOL were compared, while accounting for amputation level. Linear regression assessed relationships between physical functional status and QOL, as well as mental-health screening status.

RESULTS

Higher physical functioning scores were associated with better QOL, and lower physical functioning scores were associated with screening positive for PTSD or depression. When stratified by mental-health screening, a significant relationship was observed between mean physical functioning scores and amputation level with a negative PTSD or depression screen only. Additionally, those with bilateral amputation reported lower physical functioning.

CONCLUSIONS

Physical functioning was associated with patient-reported outcomes, including QOL and mental-health screening. Screening positive for PTSD or depression was associated with worsened self-reported physical function and may outweigh the impact of amputation severity on physical functioning. Successful rehabilitation requires the integration of physical and mental health domains in order to achieve optimal functioning.Implications for rehabilitationThe current study shows that physical functioning in participants with combat-related amputation is related to the amputation level, quality of life, and mental-health symptom screening.Good mental health is crucial to optimal functioning, as presence of adverse mental-health symptoms may exacerbate physical functional limitations among those with combat-related amputations.Assessing variables related to adverse mental-health symptoms and ultimate physical functioning outcomes is critical for clinicians to optimize rehabilitative strategies and outcomes.

Low-intensity Blast Wave Model for Preclinical Assessment of Closed-head Mild Traumatic Brain Injury in Rodents

Traumatic brain injury (TBI) is a large-scale public health problem. Mild TBI is the most prevalent form of neurotrauma and accounts for a large number of medical visits in the United States. There are currently no FDA-approved treatments available for TBI. The increased incidence of military-related, blast-induced TBI further accentuates the urgent need for effective TBI treatments. Therefore, new preclinical TBI animal models that recapitulate aspects of human blast-related TBI will greatly advance the research efforts into the neurobiological and pathophysiological processes underlying mild to moderate TBI as well as the development of novel therapeutic strategies for TBI. Here we present a reliable, reproducible model for the investigation of the molecular, cellular, and behavioral effects of mild to moderate blast-induced TBI. We describe a step-by-step protocol for closed-head, blast-induced mild TBI in rodents using a bench-top setup consisting of a gas-driven shock tube equipped with piezoelectric pressure sensors to ensure consistent test conditions. The benefits of the setup that we have established are its relative low-cost, ease of installation, ease of use and high-throughput capacity. Further advantages of this non-invasive TBI model include the scalability of the blast peak overpressure and the generation of controlled reproducible outcomes. The reproducibility and relevance of this TBI model has been evaluated in a number of downstream applications, including neurobiological, neuropathological, neurophysiological and behavioral analyses, supporting the use of this model for the characterization of processes underlying the etiology of mild to moderate TBI.

Anti-human Leukocyte Antigen Immune Sensitization Effects of Cryopreserved Allograft and Blood Transfusion

Vascularized composite allotransplantation (VCA) is the most advanced reconstructive technique available to patients who suffer devastating burns to the limbs or face. However, VCA requires donor-recipient matching. Burn patients have been reported to experience sensitization, or the development of anti-human leukocyte antigen antibodies, during resuscitation and wound coverage, potentially precluding them from future VCA. This study sought to investigate the contributions of both blood and allograft to sensitization in burn patients. Four groups were compared: burn patients who received blood products and allograft (group 1), burn patients who received blood products only (group 2), trauma patients who received blood products only (group 3), and healthy volunteer controls (group 4). The average calculated panel-reactive antibody (indicating sensitization) was higher in group 1 compared to group 4 (P = .035). Additionally, the incidence of severe sensitization was higher in group 1 relative to the other groups (P = .049). When comparing groups of patients who had no sensitization, mild sensitization, moderate sensitization, and severe sensitization, there were no significant differences in age, sex, blood products received, total body surface area burned, or allograft used between groups, though severely sensitized patients tended to have greater total body surface area involvement and received more units of packed red blood cells and allograft (P = .079, P = .196, and P = .072, respectively). We therefore conclude that while burn patients who received allograft and blood demonstrated a higher incidence of anti-human leukocyte antigen sensitization relative to healthy controls, this difference cannot solely be attributed to either allograft use or transfusion.

Manchester Arena Attack: management of paediatric penetrating brain injuries

PURPOSE

The Manchester Arena bombing on 22 May 2017 resulted in 22 deaths and over 160 casualties requiring medical attention. Given the threat of modern- era terrorist attacks in civilian environments, it is important that we are able to anticipate and appropriately manage neurological injuries associated with these events. This article describes our experience of managing paediatric neurosurgical blast injuries, from initial triage and operative management to longer-term considerations.

MATERIALS AND METHODS

Case study and literature review.

RESULTS

Paediatric traumatic and penetrating brain injury patients often make a good neurological recovery despite low GCS at time of injury; this should be accounted for during triage and operative decision making in major trauma, mass casualty events. Conservative management of retained shrapnel is advocated in view of low long-term infection rates with retained shrapnel and worsened neurological outcome with shrapnel retrieval. All penetrating brain injuries should receive a prolonged course of broad-spectrum antibiotics and undergo long term follow-up imaging to monitor for the development of cerebral abscesses. MRI should never be utilised in penetrating brain injury cases, even in the absence of macroscopically visible fragments, due to the effect of MRI ferromagnetic field torque on shrapnel fragments. Anti-epileptic drugs should only be prescribed for the initial seven days after injury, as continuing beyond this does not incur any benefit in the reduction of long term post-traumatic epilepsy.

CONCLUSION

All receiving neurosurgical units should become familiar with optimum management of these thankfully rare, but complex injuries from their initial presentation to long term follow up considerations. All neurosurgical units should have well-rehearsed local plans to follow in the event of such incidents, ensuring timely deliverance of appropriate neurosurgical care in such extreme settings.

Regionalization of Isolated Pediatric Femur Fracture Treatment: Recent Trends Observed Using the Kids' Inpatient Database

BACKGROUND

Isolated pediatric femur fractures have historically been treated at local hospitals. Pediatric referral patterns have changed in recent years, diverting patients to high volume centers. The purpose of this investigation was to assess the treatment location of isolated pediatric femur fractures and concomitant trends in length of stay and cost of treatment.

METHODS

A cross-sectional analysis of surgical admissions for femoral shaft fracture was performed using the 2000 to 2012 Kids' Inpatient Database. The primary outcome was hospital location and teaching status. Secondary outcomes included the length of stay and mean hospital charges. Polytrauma patients were excluded. Data were weighted within each study year to produce national estimates.

RESULTS

A total of 35,205 pediatric femoral fracture cases met the inclusion criteria. There was a significant shift in the treatment location over time. In 2000, 60.1% of fractures were treated at urban, teaching hospitals increasing to 81.8% in 2012 (P<0.001). Mean length of stay for all hospitals decreased from 2.59 to 1.91 days (P<0.001). Inflation-adjusted total charges increased during the study from $9499 in 2000 to $25,499 in 2012 per episode of treatment (P<0.001). Total charges per hospitalization were ∼$8000 greater at urban, teaching hospitals in 2012.

CONCLUSIONS

Treatment of isolated pediatric femoral fractures is regionalizing to urban, teaching hospitals. Length of stay has decreased across all institutions. However, the cost of treatment is significantly greater at urban institutions relative to rural hospitals. This trend does not consider patient outcomes but the observed pattern appears to have financial implications.

LEVEL OF EVIDENCE

Level III-case series, database study.

Head and neck injuries after a bomb explosion: Diagnostic findings and treatment approaches

OBJECTIVE

To identify the types and severity of head, face and neck (HFN) injuries, which occurred as a result of a bomb explosion and reached serious life-threatening levels, using radiological imaging methods, and to discuss the options of treatment at the time of presentation.

METHODS

Of the 16 patients brought to the emergency department, 14 with HFN injuries were included in the study. Computed tomography (CT) and radiography scans were performed at the time of presentation in all patients, except for one. The injuries were divided into three groups according to their localization as head, face, and neck.

RESULTS

A subgaleal hematoma was seen in 10 of 11 (78.5%) patients with head injuries. Eight (57.1%) of nine patients with facial injury had fractures and/or ocular injury in the orbital wall, and seven (50%) patients had maxillofacial bone fractures. Among ocular trauma cases, open-globe injuries were detected in three patients (21.4%), closed-globe in two (14.2%), and both types in three (21.4%). Of the five (35.7%) patients with secondary blast injuries in the neck, three (21.4%) had laryngeal trauma (Zone 2) due to shrapnel, localized in the false vocal cord, epiglottis, and thyrohyoid membrane, respectively. Emergency surgery was performed on a patient with a specific laryngeal injury.

CONCLUSION

We consider that in patients presenting to the emergency department with blast HFN injuries, after providing airway patency and hemodynamic stability, CT and CT angiography should be performed because these modalities guide the treatment accurately and promptly.

All hands on deck: Hand replantation versus transplantation

Objectives:

Our hands play a remarkable role in our activities of daily living and the make-up of our identities. In the United States, an estimated 41,000 individuals live with upper limb loss. Our expanding experience in limb transplantation—including operative techniques, rehabilitation, and expected outcomes—has often been based on our past experience with replantation. Here, we undertake a systematic review of replantation with transplantation in an attempt to better understand the determinants of outcome for each and to provide a summary of the data to this point.

Methods:

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we conducted PubMed searches from 1964 to 2013 for articles in English. In total, 53 primary and secondary source articles were found to involve surgical repair (either replantation or transplantation) for complete amputations at the wrist and forearm levels. All were read and analyzed.

Results:

Hand replantations and transplantations were compared with respect to pre-operative considerations, surgical techniques, post-operative considerations and outcomes, including motor, sensation, cosmesis, patient satisfaction/quality of life, adverse events/side effects, financial costs, and overall function. While comparison of data is limited by heterogeneity, these data support our belief that good outcomes depend on patient expectations and commitment.

Conclusion:

When possible, hand replantation remains the primary option after acute amputation. However, when replantation fails or is not possible, hand transplantation appears to provide at least equal outcomes. Patient commitment, realistic expectations, and physician competence must coincide to achieve the best possible outcomes for both hand replantation and transplantation.

Successful Treatment of War Zone Traumatic Lower Extremity Wound With Exposed Tendons Using an Autologous Homologous Skin Construct

Extremity injuries are common in contemporary combat and have become more prevalent as fatality rates have dropped to historic lows. Traumatic extremity wounds, especially those sustained in theater, often present with exposed structures such as tendon, bone, and joint, preventing the use of split-thickness skin grafts (STSG) for coverage. Traditional reconstructive options for these complex wounds include skin substitute with delayed STSG, local flaps, debridement of tendons, pedicled distant flaps (such as cross-leg flap), free tissue transfer, and amputation. STSG, whether on top of skin substitutes or after tendon debridement, can result in contracture and functional limitations in the extremities. Flap reconstructions require prolonged procedures, hospital stays, and periods of immobility. As an alternative to traditional reconstructive options, an autologous homologous skin construct (AHSC) uses a small full-thickness elliptical skin harvest from the patient, which is sent to a biomedical manufacturing facility, processed into AHSC, and can be returned and applied to a wound bed as soon as 48 hours after harvest and used up to 14 days after harvest. We present in this case report the treatment of a 42 cm² complex dorsolateral ankle wound with exposed tendons in an active duty soldier following a rollover motor vehicle accident sustained in theater. After application of AHSC, the soldier’s wound closed in nine weeks with pliable, sensate skin. The patient retained function without contractures limiting ankle motion or adhesions limiting tendon gliding. The successful treatment of this complex war zone injury with AHSC has allowed the soldier to quickly participate in unrestricted physical therapy and is on a trajectory for near-term return to active duty.

Multimorbidity and quality of life after blast-related injury among US military personnel: a cluster analysis of retrospective data

Background

Blast injury emerged as a primary source of morbidity among US military personnel during the recent conflicts in Iraq and Afghanistan, and led to an array of adverse health outcomes. Multimorbidity, or the presence of two or more medical conditions in an individual, can complicate treatment strategies. To date, there is minimal research on the impact of multimorbidity on long-term patient-reported outcomes. We aimed to define multimorbidity patterns in a population of blast-injured military personnel, and to examine these patterns in relation to long-term quality of life (QOL).

Methods

A total of 1972 US military personnel who sustained a blast-related injury during military operations in Iraq and Afghanistan were identified from clinical records. Electronic health databases were used to identify medical diagnoses within the first year postinjury, and QOL was measured with a web-based assessment. Hierarchical cluster analysis methods using Ward’s minimum variance were employed to identify clusters with related medical diagnosis categories. Duncan’s multiple range test was used to group clusters into domains by QOL.

Results

Five distinct clusters were identified and grouped into three QOL domains. The lowest QOL domain contained one cluster with a clinical triad reflecting musculoskeletal pain, concussion, and mental health morbidity. The middle QOL domain had two clusters, one with concussion/anxiety predominating and the other with polytrauma. The highest QOL domain had two clusters with little multimorbidity aside from musculoskeletal pain.

Conclusions

The present study described blast-related injury profiles with varying QOL levels that may indicate the need for integrated health services. Implications exist for current multidisciplinary care of wounded active duty and veteran service members, and future research should determine whether multimorbidity denotes distinct post-blast injury syndromes.

Ex vivo limb perfusion for traumatic amputation in military medicine

BACKGROUND

Limb loss has a drastic impact on a patient's life. Severe trauma to the extremities is common in current military conflicts. Among other aspects, "life before limb" damage control surgery hinders immediate replantation within the short post-traumatic timeframe, which is limited in part by the ischemic time for successful replantation. Ex vivo limb perfusion is currently being researched in animal models and shows promising results for its application in human limb replantation and allotransplantation.

PRESENTATION OF THE HYPOTHESIS

The current lack of replantation possibilities in military operations with high rates of amputation can be addressed with the development of a portable ex vivo limb perfusion device, as there are several opportunities present with the introduction of this technique on the horizon. We hypothesize that ex vivo limb perfusion will enable overcoming the critical ischemic time, provide surgical opportunities such as preparation of the stump and limb, allow for spare-part surgery, enable rigorous antibiotic treatment of the limb, reduce ischemia-reperfusion injuries, enable a tissue function assessment before replantation, and enable the development of large limb transplant programs.

TESTING THE HYPOTHESIS

Data from in vivo studies in porcine models are limited by the relatively short perfusion time of 24 h. In the military setting, notably longer perfusion times need to be realized. Therefore, future animal studies must focus especially on long-term perfusion, since this represents the military setting, considering the time for stabilization of the patient until evacuation to a tertiary treatment center.

IMPLICATIONS OF THE HYPOTHESIS

The development and clinical introduction of ex vivo limb perfusion in the military setting could lead to a drastic reduction in the number of limb amputations among service members. Ex vivo limb perfusion enables replantation surgery in Role 4 facilities and changes the clinical setting from a highly urgent, life-threatening situation to a highly methodical, well-prepared starting point for optimal treatment of the wounded service member. With its introduction, the principle of "life before limb" will change to "life before limb before elective replantation/allotransplantation after ex vivo limb perfusion".

PWD: Treatment Platform for Both Prolonged Field Care and Definitive Treatment of Burn-Injured Warfighters

INTRODUCTION

Burns are a very frequent injury type in the battlefield, comprising 5-20% of combat casualties in the recent conflicts. Almost 80% of the burns occur to the face, in part because the face is often not protected. Immediate treatment is critical in the first hours after severe burn injury in order to prevent infection and wound progression. Immediate treatment in the battlefield can be a serious challenge especially if the injury occurs in a remote area with limited transport options. Therefore, novel treatment modalities for prolonged field care when transport to the definitive care is delayed are needed. The purpose of this study was to utilize the platform wound device (PWD) with negative pressure capabilities for the immediate and definitive treatment of porcine full-thickness head burns.

MATERIALS AND METHODS

Full-thickness burn wounds were created on foreheads of seven Yorkshire pigs. Burns were created on day 0, immediately enclosed with the PWD and treated topically with minocycline and lidocaine. On day 3, the burns were surgically debrided. Subsequently, new PWDs were placed on the wounds and continuous negative pressure wound therapy was initiated with either -50 mmHg or -80 mmHg. On day 7, the animals were euthanized and wounds were harvested for analyses. Control wounds were treated with silver sulfadiazine cream.

RESULTS

The PWD treatment with negative pressure significantly reduced erythema and edema in the injured tissue and promoted granulation tissue and neocollagen formation by day 7 in comparison to control wounds. In addition, the PWD with both topical minocycline and negative pressure (-80 mmHg or -50 mmHg) reduced bacterial counts in the wounds similar to the current standard of care.

CONCLUSION

This study demonstrates that the PWD is an effective platform for delivery of antibiotics and negative pressure wound therapy for the treatment of full-thickness burns. Therefore, the PWD may be utilized for both prolonged field care and definitive treatment of burn- and blast-injured warfighters.

Reference data on in vitro anatomy and indentation response of tissue layers of musculoskeletal extremities

The skin, fat, and muscle of the musculoskeletal system provide essential support and protection to the human body. The interaction between individual layers and their composite structure dictate the body's response during mechanical loading of extremity surfaces. Quantifying such interactions may improve surgical outcomes by enhancing surgical simulations with lifelike tissue characteristics. Recently, a comprehensive tissue thickness and anthropometric database of in vivo extremities was acquired using a load sensing instrumented ultrasound to enhance the fidelity of advancing surgical simulations. However detailed anatomy of tissue layers of musculoskeletal extremities was not captured. This study aims to supplement that database with an enhanced dataset of in vitro specimens that includes ultrasound imaging supported by motion tracking of the ultrasound probe and two additional full field imaging modalities (magnetic resonance and computed tomography). The additional imaging datasets can be used in conjunction with the ultrasound/force data for more comprehensive modeling of soft tissue mechanics. Researchers can also use the image modalities in isolation if anatomy of legs and arms is needed.

A Review of the Role of Auditory Evoked Potentials in Mild Traumatic Brain Injury Assessment

Around 75% to 90% of people who experience a traumatic brain injury (TBI) are classified as having a mild TBI (mTBI). The term mTBI is synonymous with concussion or mild head injury (MHI) and is characterized by symptoms of headache, nausea, dizziness, and blurred vision. Problems in cognitive abilities such as deficits in memory, processing speed, executive functioning, and attention are also considered symptoms of mTBI. Since these symptoms are subtle in nature and may not appear immediately following the injury, mTBI is often undetected on conventional neuropsychological tests. Current neuroimaging techniques may not be sensitive enough in identifying the array of microscopic neuroanatomical and subtle neurophysiological changes following mTBI. To this end, electrophysiological tests, such as auditory evoked potentials (AEPs), can be used as sensitive tools in tracking physiological changes underlying physical and cognitive symptoms associated with mTBI. The purpose of this review article is to examine the body of literature describing the application of AEPs in the assessment of mTBI and to explore various parameters of AEPs which may hold diagnostic value in predicting positive rehabilitative outcomes for people with mTBI.