PubTransformer

A site to transform Pubmed publications into these bibliographic reference formats: ADS, BibTeX, EndNote, ISI used by the Web of Knowledge, RIS, MEDLINE, Microsoft's Word 2007 XML.

Wounds and Injuries - Top 30 Publications

Muscle contributions to medial tibiofemoral compartment contact loading following ACL reconstruction using semitendinosus and gracilis tendon grafts.

The muscle-tendon properties of the semitendinosus (ST) and gracilis (GR) are substantially altered following tendon harvest for the purpose of anterior cruciate ligament reconstruction (ACLR). This study adopted a musculoskeletal modelling approach to determine how the changes to the ST and GR muscle-tendon properties alter their contribution to medial compartment contact loading within the tibiofemoral joint in post ACLR patients, and the extent to which other muscles compensate under the same external loading conditions during walking, running and sidestep cutting.

The evolution of cost-efficiency in neural networks during recovery from traumatic brain injury.

A somewhat perplexing finding in the systems neuroscience has been the observation that physical injury to neural systems may result in enhanced functional connectivity (i.e., hyperconnectivity) relative to the typical network response. The consequences of local or global enhancement of functional connectivity remain uncertain and this is particularly true for the overall metabolic cost of the network. We examine the hyperconnectivity hypothesis in a sample of 14 individuals with TBI with data collected at approximately 3, 6, and 12 months following moderate and severe TBI. As anticipated, individuals with TBI showed increased network strength and cost early after injury, but by one-year post injury hyperconnectivity was more circumscribed to frontal DMN and temporal-parietal attentional control regions. Cost in these subregions was a significant predictor of cognitive performance. Cost-efficiency analysis in the Power 264 data parcellation suggested that at 6 months post injury the network requires higher cost connections to achieve high efficiency as compared to the network 12 months post injury. These results demonstrate that networks self-organize to re-establish connectivity while balancing cost-efficiency trade-offs.

Defining the complex phenotype of severe systemic loxoscelism using a large electronic health record cohort.

Systemic loxoscelism is a rare illness resulting from the bite of the recluse spider and, in its most severe form, can lead to widespread hemolysis, coagulopathy, and death. We aim to describe the clinical features and outcomes of the largest known cohort of individuals with moderate to severe loxoscelism.

Adolescent with prolonged toxidrome.

A 13-year-old female was presented to the emergency department following an intentional ingestion. The patient developed significant toxicity including multiple, discreet tonic-clonic seizures. Despite appropriate resuscitation and antidotal management, the patient's symptoms persisted for more than 36 hours post-ingestion. An upright abdominal radiograph was performed revealing a radiopacity suggesting a pharmacobezoar. An esophagogastroduodenoscopy was performed with successful removal of a tennis ball-sized pharmacobezoar. The patient's symptoms subsequently subsided and she recovered fully with no neurologic deficits. Diphenhydramine has not been previously identified as a medication likely to form a pharmacobezoar and has not been shown to be radiopaque. Though bezoar formation is a rare clinical scenario, it is one that toxicologists must consider in patients with clinical courses that persist far beyond expected based on known toxicokinetic principles.

Electrophysiological, Morphological, and Ultrastructural Features of the Injured Spinal Cord Tissue after Transplantation of Human Umbilical Cord Blood Mononuclear Cells Genetically Modified with the VEGF and GDNF Genes.

In this study, we examined the efficacy of human umbilical cord blood mononuclear cells (hUCB-MCs), genetically modified with the VEGF and GDNF genes using adenoviral vectors, on posttraumatic regeneration after transplantation into the site of spinal cord injury (SCI) in rats. Thirty days after SCI, followed by transplantation of nontransduced hUCB-MCs, we observed an improvement in H (latency period, LP) and M(Amax) waves, compared to the group without therapy after SCI. For genetically modified hUCB-MCs, there was improvement in Amax of M wave and LP of both the M and H waves. The ratio between Amax of the H and M waves (Hmax/Mmax) demonstrated that transplantation into the area of SCI of genetically modified hUCB-MCs was more effective than nontransduced hUCB-MCs. Spared tissue and myelinated fibers were increased at day 30 after SCI and transplantation of hUCB-MCs in the lateral and ventral funiculi 2.5 mm from the lesion epicenter. Transplantation of hUCB-MCs genetically modified with the VEGF and GNDF genes significantly increased the number of spared myelinated fibers (22-fold, P > 0.01) in the main corticospinal tract compared to the nontransduced ones. HNA(+) cells with the morphology of phagocytes and microglia-like cells were found as compact clusters or cell bridges within the traumatic cavities that were lined by GFAP(+) host astrocytes. Our results show that hUCB-MCs transplanted into the site of SCI improved regeneration and that hUCB-MCs genetically modified with the VEGF and GNDF genes were more effective than nontransduced hUCB-MCs.

Tau phosphorylation induced by severe closed head traumatic brain injury is linked to the cellular prion protein.

Studies in vivo and in vitro have suggested that the mechanism underlying Alzheimer's disease (AD) neuropathogenesis is initiated by an interaction between the cellular prion protein (PrP(C)) and amyloid-β oligomers (Aβo). This PrP(C)-Aβo complex activates Fyn kinase which, in turn, hyperphosphorylates tau (P-Tau) resulting in synaptic dysfunction, neuronal loss and cognitive deficits. AD transgenic mice lacking PrP(C) accumulate Aβ, but show normal survival and no loss of spatial learning and memory suggesting that PrP(C) functions downstream of Aβo production but upstream of intracellular toxicity within neurons. Since AD and traumatic brain injury (TBI)-linked chronic traumatic encephalopathy are tauopathies, we examined whether similar mechanistic pathways are responsible for both AD and TBI pathophysiologies. Using transgenic mice expressing different levels of PrP(C), our studies investigated the influence and necessity of PrP(C) on biomarker (total-tau [T-Tau], P-Tau, GFAP) levels in brain and blood as measured biochemically following severe TBI in the form of severe closed head injury (sCHI). We found that following sCHI, increasing levels of T-Tau and P-Tau in the brain were associated with the PrP(C) expression levels. A similar relationship between PrP(C) expression and P-Tau levels following sCHI were found in blood in the absence of significant T-Tau changes. This effect was not seen with GFAP which increased within 24 h following sCHI and progressively decreased by the 7 day time point regardless of the PrP(C) expression levels. Changes in the levels of all biomarkers were independent of gender. We further enhanced and expanded the quantitation of brain biomarkers with correlative studies using immunohisochemistry. We also demonstrate that a TBI-induced calpain hyperactivation is not required for the generation of P-Tau. A relationship was demonstrated between the presence/absence of PrP(C), the levels of P-Tau and cognitive dysfunction. Our studies suggest that PrP(C) is important in mediating TBI related pathology.

Geriatric Fracture Care: Future Trajectories: A 2015 AOA Critical Issues Symposium.

The population of the United States and the world is aging rapidly. Musculoskeletal care for older adults will be impacted by the manner in which health care is financed and the ability of the orthopaedic community to provide evidence-based integrated care for this population. We review the financial aspects of health-care reform and the implications for musculoskeletal care in the elderly. We discuss the establishment of quality measures for hip fracture care in the elderly, team building to accomplish this, and an innovative program designed to provide orthopaedic care to the frail elderly outside of the usual office setting.

Emerging U.S. National Trends in the Treatment of Pediatric Supracondylar Humeral Fractures.

Understanding national trends in the treatment of pediatric supracondylar humeral fractures will provide important insight into variations in regional treatment and identify areas for improving value and quality in care delivery in the U.S.

Clinical Practice Guidelines Decrease Unnecessary Echocardiograms Before Hip Fracture Surgery.

Preoperative assessment of geriatric patients with a hip fracture may include transthoracic echocardiography (TTE), which increases resource utilization and cost and may delay surgery. The purpose of this study was to evaluate preoperative TTE utilization at a single institution in order to determine (1) how often TTE is ordered in accordance with clinical practice guidelines (CPGs), (2) how frequently TTE reveals cardiac disease that may alter medical or anesthesia management, and (3) whether following CPGs reduces unnecessary TTE utilization without potentially missing important disease.

Complications and Functional Outcomes After Pantalar Dislocation.

Pantalar dislocations without associated talar fracture are rare and have high risks of complications, including infection, osteonecrosis, and posttraumatic osteoarthrosis. Limited information on later function exists. This study evaluated complications and outcomes following pantalar dislocation without talar fracture.

Science to Practice: Quantitative US Elastography Can Be Used to Quantify Mechanical and Histologic Tendon Healing in a Rabbit Model of Achilles Tendon Transection.

Compression-based ultrasonographic (US) elastography is associated with time-dependent mechanical and histologic changes of the healing tendon in a transected rabbit model of the Achilles tendon. This finding will lead to continued development of quantitative US, which can be used to objectively assess a diseased or healing tendon. With advances in the method used, clinical translation of tendon elastography may enable clinicians to diagnose tendon damage and track healing, which should improve both treatment and outcome.

Creation of an intramedullary cavity by hemorrhagic necrosis removal 24 h after spinal cord contusion in rats for eventual intralesional implantation of restorative materials.

Intramedullary hemorrhagic necrosis occurs early after spinal cord injury at the site of injury and adjacent segments. It is considered harmful because of its potential to aggravate secondary injury, and to interfere with axonal regeneration; it might also lead to an unfavorable environment for intralesional implants. Removal of hemorrhagic necrosis has been attempted before with variable results. The invasive nature of these procedures carries the risk of exacerbating damage to the injured cord. The overall objective for this study was to test several strategies for non-damaging removal of hemorrhagic necrosis and characterize the resulting cavity looking for a space for future intralesional therapeutic implants in rats with acute cord injury. Rats were subjected to graded cord contusion, and hemorrhagic necrosis was removed after 24h. Three grades of myelotomy (extensive, medium sized, and small) were tested. Using the small surgical approach to debridement, early and late effects of the intervention were determined by histology and by analytical and behavioral analysis. Appearance and capacity of the resulting cavity were characterized. Satisfactory removal of hemorrhagic necrosis was achieved with all three surgical approaches to debridement. However, bleeding in spared cord tissue was excessive after medium sized and extensive myelotomies but similar to control injured rats after small cord surgery. Small surgical approach to debridement produced no swelling nor acute inflammation changes, nor did it affect long-term spontaneous locomotor recovery, but resulted in modest improvement of myelination in rats subjected to both moderate and severe injuries. Cavity created after intervention was filled with 10 to 15 μL of hydrogel. In conclusion, by small surgical approach to debridement, removal of hemorrhagic necrosis was achieved after acute cord contusion thereby creating intramedullary spaces without further damaging the injured spinal cord. Resulting cavities appear suitable for future intralesional placement of pro-reparative cells or other regenerative biomaterials in a clinically relevant model of spinal cord injury.

Tactical Combat Casualty Care and Wilderness Medicine: Advancing Trauma Care in Austere Environments.

Tactical Combat Casualty Care (TCCC) is a set of evidence-based, best-practice prehospital trauma care guidelines customized for use on the battlefield. Military units that have trained all of their unit members in TCCC have now documented the lowest incidence of preventable deaths in the history of modern warfare and TCCC is now the standard for battlefield trauma care in the US Military. TCCC and wilderness medicine share the goal of optimizing care for patients with trauma in austere environments that impose significant challenges in both equipment and evacuation capability. This article reviews the current battlefield trauma care recommendations in TCCC and discusses their applicability to the wilderness setting.

Arthropod Envenomation in North America.

Arthropods (phylum Arthopoda) account for a higher percentage of morbidity and mortality to humans than do mammalian bites, snake bites, or marine envenomation. They are ubiquitous in domestic dwellings, caves, and campsites and in wilderness settings such as deserts, forests, and lakes. Although arthropods are most intrusive during warmer months, many are active throughout the winter, particularly indoors. Arthropods are also nocturnal and often bite unsuspecting victims while they are sleeping. Encounters with humans are generally defensive, accidental, or reactive. An individual stung by an insect or bitten by an arachnid may experience pain and local swelling, an anaphylactic reaction, or life-threatening toxicity. This review discusses the clinical presentation and latest treatment recommendations for bites and stings from spiders, scorpions, bees, ants, ticks and centipedes of North America.

North American Snake Envenomation.

Native US snakes that produce clinically significant envenomation can be divided into 2 groups, crotalids and elapids. The crotalids include rattlesnakes, cottonmouths, and copperheads. Crotalid envenomation can result in significant local tissue damage as well as thrombocytopenia and coagulopathy. Rarely are bites fatal. Native US elapids are all coral snakes that possess neurotoxic venom that can cause weakness, respiratory paralysis, and rarely death. Treatment of both types of envenomation revolves around general supportive care and antivenom administration when indicated. Previously advocated treatments, such as tourniquets, venom extraction, and bite site excision are not recommended.

Marine Envenomation.

Venomous aquatic animals are hazardous to swimmers, surfers, divers, and fishermen. Exposures include mild stings, bites, abrasions, and lacerations. Severe envenomations can be life threatening. This article reviews common marine envenomations, exploring causative species, clinical presentation, and current treatment recommendations. Recommendations are included for cnidaria, sponges, bristle worms, crown-of-thorns starfish, sea urchins, venomous fish, stingrays, cone snails, stonefish, blue-ringed octopus, and sea snakes. Immediate and long-term treatment options and management of common sequelae are reviewed. Antivenom administration, treatment of anaphylaxis, and surgical indications are discussed.

Updates in Decompression Illness.

Decompression sickness and arterial gas embolism, collectively known as decompression illness (DCI), are rare but serious afflictions that can result from compressed gas diving exposures. Risk is primarily determined by the pressure-time profile but is influenced by several factors. DCI can present idiosyncratically but with a wide range of neurologic symptoms. Examination is critical for assessment in the absence of diagnostic indicators. Many conditions must be considered in the differential diagnosis. High-fraction oxygen breathing provides first aid but definitive treatment of DCI is hyperbaric oxygen.

Frostbite.

Deep frostbite is a thermal injury associated with significant morbidity. Historically, this has been associated with military personnel; however, increasingly it is becoming an injury that afflicts the civilian population. The use of intravenous iloprost or intra-arterial thrombolytics has led to promising tissue salvage. This article provides an up-to-date understanding of frostbite pathophysiology, classification, prevention, and management. It also highlights the role of telemedicine in optimizing patient outcomes. To further the understanding of optimal frostbite management, larger, likely multicenter, high-quality trials are required. An international frostbite register would facilitate data gathering.

Axonal damage and loss of connectivity in nigrostriatal and mesolimbic dopamine pathways in early Parkinson's disease.

A progressive loss of dopamine neurons in the substantia nigra (SN) is considered the main feature of idiopathic Parkinson's disease (PD). Recent neuropathological evidence however suggests that the axons of the nigrostriatal dopaminergic system are the earliest target of α-synuclein accumulation in PD, thus the principal site for vulnerability. Whether this applies to in vivo PD, and also to the mesolimbic system has not been investigated yet. We used [(11)C]FeCIT PET to measure presynaptic dopamine transporter (DAT) activity in both nigrostriatal and mesolimbic systems, in 36 early PD patients (mean disease duration in months ± SD 21.8 ± 10.7) and 14 healthy controls similar for age. We also performed anatomically-driven partial correlation analysis to evaluate possible changes in the connectivity within both the dopamine networks at an early clinical phase. In the nigrostriatal system, we found a severe DAT reduction in the afferents to the dorsal putamen (DPU) (η(2) = 0.84), whereas the SN was the less affected region (η(2) = 0.31). DAT activity in the ventral tegmental area (VTA) and the ventral striatum (VST) were also reduced in the patient group, but to a lesser degree (VST η(2) = 0.71 and VTA η(2) = 0.31). In the PD patients compared to the controls, there was a marked decrease in dopamine network connectivity between SN and DPU nodes, supporting the significant derangement in the nigrostriatal pathway. These results suggest that neurodegeneration in the dopamine pathways is initially more prominent in the afferent axons and more severe in the nigrostriatal system. Considering PD as a disconnection syndrome starting from the axons, it would justify neuroprotective interventions even if patients have already manifested clinical symptoms.

Radiation-Induced Dermatitis is Mediated by IL17-Expressing γδ T Cells.

Radiation dermatitis is a serious cutaneous injury caused by radiation therapy or upon accidental nuclear exposure. However, the pathogenic immune mechanisms underlying this injury are still poorly understood. We seek to discover how the dysregulated immune response after irradiation orchestrates skin inflammation. The skin on the left flank of C57BL/6J wild-type and C57BL/6J Tcrd(-/-) mice, which are deficit in γδ T cells, was exposed to a single X-ray dose of 25 Gy, and the right-flank skin was used as a sham-irradiated control. At 4 weeks postirradiation, the wild-type skin exhibited signs of depilation, erythema and desquamation. Histological analysis showed hyperproliferation of keratinocytes and acanthosis. Dramatic elevation of IL17-expressing T cells was identified from the irradiated skin, which was mainly contributed by γδ T cells and innate lymphoid cells, rather than Th17 cells. Furthermore, protein levels of critical cytokines for IL17-expressing γδ T cell activation, IL1β and IL23 were found markedly upregulated. Lastly, radiation-induced dermatitis was significantly attenuated in γδ T cell knockout mice. In vitro, normal human epidermal keratinocytes (NHEKs) could be initiator cells of inflammation by providing a great number of pro-inflammatory mediators upon radiation, and as well as effector cells of epidermal hyperplasia in response to exogenous IL17 and/or IL22 treatment. Our findings implicate a novel role of IL17-expressing γδ T cells in mediating radiation-induced skin inflammation. This study reveals the innate immune response pathway as a potential therapeutic target for radiation skin injury.

Differences Between Women With Traumatic and Idiopathic Chronic Neck Pain and Women Without Neck Pain: Interrelationships Among Disability, Cognitive Deficits, and Central Sensitization.

To date, a clear differentiation of disability, cognitive deficits, and central sensitization between chronic neck pain of a traumatic nature and that of a nontraumatic nature is lacking.

Simulated blast overpressure induces specific astrocyte injury in an ex vivo brain slice model.

Exposure to explosive blasts can produce functional debilitation in the absence of brain pathology detectable at the scale of current diagnostic imaging. Transient (ms) overpressure components of the primary blast wave are considered to be potentially damaging to the brain. Astrocytes participate in neuronal metabolic maintenance, blood-brain barrier, regulation of homeostatic environment, and tissue remodeling. Damage to astrocytes via direct physical forces has the potential to disrupt local and global functioning of neuronal tissue. Using an ex vivo brain slice model, we tested the hypothesis that viable astrocytes within the slice could be injured simply by transit of a single blast wave consisting of overpressure alone. A polymer split Hopkinson pressure bar (PSHPB) system was adapted to impart a single positive pressure transient with a comparable magnitude to those that might be present inside the head. A custom built test chamber housing the brain tissue slice incorporated revised design elements to reduce fluid space and promote transit of a uniform planar waveform. Confocal microscopy, stereology, and morphometry of glial fibrillary acidic protein (GFAP) immunoreactivity revealed that two distinct astrocyte injury profiles were identified across a 4 hr post-test survival interval: (a) presumed conventional astrogliosis characterized by enhanced GFAP immunofluorescence intensity without significant change in tissue area fraction and (b) a process comparable to clasmatodendrosis, an autophagic degradation of distal processes that has not been previously associated with blast induced neurotrauma. Analysis of astrocyte branching revealed early, sustained, and progressive differences distinct from the effects of slice incubation absent overpressure testing. Astrocyte vulnerability to overpressure transients indicates a potential for significant involvement in brain blast pathology and emergent dysfunction. The testing platform can isolate overpressure injury phenomena to provide novel insight on physical and biological mechanisms.

Melatonin protects rats from radiotherapy-induced small intestine toxicity.

Radiotherapy-induced gut toxicity is among the most prevalent dose-limiting toxicities following radiotherapy. Prevention of radiation enteropathy requires protection of the small intestine. However, despite the prevalence and burden of this pathology, there are currently no effective treatments for radiotherapy-induced gut toxicity, and this pathology remains unclear. The present study aimed to investigate the changes induced in the rat small intestine after external irradiation of the tongue, and to explore the potential radio-protective effects of melatonin gel. Male Wistar rats were subjected to irradiation of their tongues with an X-Ray YXLON Y.Tu 320-D03 irradiator, receiving a dose of 7.5 Gy/day for 5 days. For 21 days post-irradiation, rats were treated with 45 mg/day melatonin gel or vehicle, by local application into their mouths. Our results showed that mitochondrial oxidative stress, bioenergetic impairment, and subsequent NLRP3 inflammasome activation were involved in the development of radiotherapy-induced gut toxicity. Oral treatment with melatonin gel had a protective effect in the small intestine, which was associated with mitochondrial protection and, consequently, with a reduced inflammatory response, blunting the NF-κB/NLRP3 inflammasome signaling activation. Thus, rats treated with melatonin gel showed reduced intestinal apoptosis, relieving mucosal dysfunction and facilitating intestinal mucosa recovery. Our findings suggest that oral treatment with melatonin gel may be a potential preventive therapy for radiotherapy-induced gut toxicity in cancer patients.

Impact of Body Mass Index and Bacterial Resistance in Osteomyelitis after Antibiotic Prophylaxis of Open Lower-Extremity Fractures.

We investigated the clinical effectiveness of antimicrobial prophylaxis in lower-extremity open fractures following the Eastern Association for the Surgery of Trauma Guidelines.

Risk and Protective Factors Associated with Surgical Infections among Spine Patients.

The purpose of the study was to identify patient-specific and procedure-specific risk and protective factors associated with post-operative surgical site infections (SSIs) among surgical spine patients.

Stochasticity among Antibiotic-Resistance Profiles of Common Burn-Related Pathogens over a Six-Year Period.

One of the most significant contributors to morbidity and death in patients with burns is infection, which accounts for 30%-75% of post-burn fatalities. Because of concerns for the development of antibiotic resistance in burn-related pathogens, the aims of this study were to identify antibiotic resistance trends for the four most common burn-related pathogens over a six-year period.

Alleviation of Ultraviolet B-Induced Photodamage by Coffea arabica Extract in Human Skin Fibroblasts and Hairless Mouse Skin.

Coffea arabica extract (CAE) containing 48.3 ± 0.4 mg/g of chlorogenic acid and a trace amount of caffeic acid was found to alleviate photoaging activity in human skin fibroblasts. In this study, polyphenol-rich CAE was investigated for its antioxidant and antiinflammatory properties, as well as for its capability to alleviate ultraviolet B (UVB)-induced photodamage in BALB/c hairless mice. The results indicated that 500 μg/mL of CAE exhibited a reducing power of 94.7%, ferrous ion chelating activity of 46.4%, and hydroxyl radical scavenging activity of 20.3%. The CAE dose dependently reduced UVB-induced reactive oxygen species (ROS) generation in fibroblasts. Furthermore, CAE inhibited the UVB-induced expression of cyclooxygenase-2 and p-inhibitor κB, and the translocation of nuclear factor-kappa B (NF-κB) to the nucleus of fibroblasts. In addition, CAE alleviated UVB-induced photoaging and photodamage in BALB/c hairless mice by restoring the collagen content and reduced UVB-induced epidermal hyperplasia. CAE also inhibited UVB-induced NF-κB, interleukin-6, and matrix metalloproteinase-1 expression in the hairless mouse skin. The results indicated that CAE exhibits antiphotodamage activity by inhibiting UV-induced oxidative stress and inflammation. Therefore, CAE is a candidate for use in antioxidant, antiinflammatory, and antiphotodamage products.

Prospective assessment of oral mucositis and its impact on quality of life and patient-reported outcomes during radiotherapy for head and neck cancer.

Oral mucositis (OM) is a common acute side effect during radiotherapy treatments for head and neck cancer (HNC), with a potential impact on patient's compliance to therapy, quality of life (QoL) and clinical outcomes. Its timely and appropriate management is of paramount importance. Several quantitative scoring scales are available to properly assess OM and its influence on patient-reported outcomes (PROs) and QoL. We prospectively assessed OM in a cohort of HNC patients submitted to radiation using the Oral Mucositis Assessment Scale (OMAS), while its impact on PROs and QoL was evaluated employing the Oral Mucositis Weekly Questionnaire-Head and Neck Cancer (OMWQ-HN) and the Functional Assessment of Cancer Therapy-Head and Neck Cancer (FACT-HN). Evaluation of OMAS scores highlighted a progressive increase in OM during treatment and a partial recovery after the end of radiation. These trends were correlated to PROs and QoL as evaluated with OMWQ-HN and FACT-HN questionnaires. In the present study, we provided a quantitative assessment of OM, PROs and QoL in HNC patient undergoing radiotherapy, potentially useful for future comparison.

Risk of firearm injuries among children and youth of immigrant families.

Firearm injuries contribute to substantial morbidity and mortality. The immigrant paradox suggests that, despite being more socially disadvantaged, immigrants are less likely than nonimmigrants to have poor outcomes. We tested the association of immigrant characteristics with firearm injuries among children and youth.

Rates of Persistent Postconcussive Symptoms.