Localized, time-dependent responses of rat cranial bone to repeated mild traumatic brain injuries

While it is well-established that bone responds dynamically to mechanical loading, the effects of mild traumatic brain injury (mTBI) on cranial bone composition are unclear. We hypothesized that repeated mTBI (rmTBI) would change the microstructure of cranial bones, without gross skull fractures. To address this, young adult female Piebald Viral Glaxo rats received sham, 1x, 2x or 3x closed-head mTBIs delivered at 24h intervals, using a weight drop device custom built for reproducible impact. Skull bones were collected at 2 or 10 weeks after the final injury/sham procedure, imaged by micro computed tomography and analyzed at predetermined regions of interest. In the interparietal bone, proximal to the injury site, modest increases in bone thickness was observed at 2 weeks, particularly following 3x mTBI. By 10 weeks, 2x mTBI induced a robust increase in the volume and thickness of the interparietal bone, alongside a corresponding decrease in the volume of marrow cavities in the diploe region. In contrast, neither parietal nor frontal skull samples were affected by rmTBI. Our findings demonstrate time- and location-dependent effects of rmTBI on cranial bone structure, highlighting a need to consider microstructural alterations to cranial bone when assessing the consequences of rmTBI.

Bilateral abducens palsy in closed head injury: A comprehensive review of literature based on a case report

Isolated bilateral sixth nerve palsies are rare, particularly in the setting of trauma. Most post-head injury cases with bilateral abducens palsy involve either basal skull fractures, particularly clival fractures. We present a case of bilateral abducens palsy after closed head injury in a young male who presented to the emergency department and a comprehensive literature review based on our clinical case. A Medline search for bilateral abducens palsy in closed head injury showed 89 results. Articles were excluded if crush head injury, non-traumatic bilateral abducens nerve palsy, associated vascular malformations were reported. After thorough search and filtering of those articles, fifty-one publications were found which reported and discussed about traumatic bilateral abducens palsy with closed head injury. In these 51 articles, a total of 139 cases were recorded. Several theories have been postulated to explain mechanisms of abducens nerve injury in trauma both in immediate and delayed settings. In our case, patient presented with immediate onset of bilateral abducens palsy. On imaging, clival fracture was seen in CT brain, which can be attributed for the nerve injury. Cases with retroclival extradural haematoma had higher chances of multiple cranial nerve injuries. Cases with multiple basal skull fracture involving petrous temporal bone fracture had higher chances of facial nerve injury. Along with bilateral involvement, the poorer outcome for recovery can be related with the severity of the adduction deficit. Our case showed no improvement in bilateral abduction during follow-up at 6 months. Clinical presentation of traumatic bilateral abducens nerve palsy is rare following closed head trauma and is usually associated with other injuries which are incompatible with life. It can be associated with other nerve injuries depending on basal skull fractures.

Progress in Cheerleading Safety: Update on the Epidemiology of Cheerleading Injuries Presenting to US Emergency Departments, 2010-2019

Background: Although the athleticism required of cheerleaders has increased, the risks of cheerleading have been less studied as compared with other sports. Purpose: To update our understanding of the epidemiology of cheerleading-related injuries. Study Design: Descriptive epidemiology study. Methods: We analyzed the National Electronic Injury Surveillance System (NEISS) for cheerleading-related injuries presenting to nationally representative emergency departments (EDs) in the United States from January 2010 through December 2019. Extracted data included patient age and sex, injury characteristics (diagnosis, body region injured, time of year, and location where injury occurred), and hospital disposition. Using patient narratives, we recorded the cheerleading skills, settings, and mechanisms that led to injury. NEISS sample weights were used to derive national estimates (NEs) from actual case numbers. Results: From 2010 to 2019, a total of 9868 athletes (NE = 350,000; 95% CI, 250,000-450,000) aged 5-25 years presented to US EDs for cheerleading injuries. The annual number of injuries decreased by 15%, from 982 (NE = 35,000; 95% CI, 27,000-44,000) to 897 (NE = 30,000; 95% CI, 18,000-42,000) ( P = .048), corresponding to a 27% decline in the injury rate per 100,000 cheerleaders ( P < .01). The annual number of injuries caused by performing stunts decreased by 24%, from 240 (NE = 8700; 95% CI, 6700-11,000) to 216 (NE = 6600; 95% CI, 4000-9200) ( P = .01), with a 36% decline in the corresponding injury rate per 100,000 cheerleaders ( P < .01). Despite these decreases, annual incidence of concussions/closed head injuries increased by 44%, from 128 (NE = 3800; 95% CI, 2900-4700) to 171 (NE = 5500; 95% CI, 3400-7700) ( P = .02), and patients requiring hospital admission increased by 118%, from 18 (NE = 330; 95% CI, 250-410) to 24 (NE = 720; 95% CI, 440-1000) ( P < .01). The hospital admission rate increased by 9.0% ( P = .02). Conclusion: The number of cheerleading-related injuries presenting to US EDs decreased from 2010 to 2019. However, the incidence of concussions/closed head injuries and hospital admissions increased, suggesting that further measures are needed to improve safety for cheerleaders.

Ultrasound in Detection of Skull Fractures in Children Younger Than Two Years Old with Closed Head Injuries

Background Paediatrics head injuries is a frequent cause of emergency department (ER) visits. The incidence of head traumas in children varies from one country to other with an estimated 47 to 280 per 100,000 children presented to the ER each year due to traumatic brain injury worldwide. Head computed tomography (CT) is the most frequent CT scan performed in paediatrics population, majority of those scans are done to evaluate trauma. Head CT scans increase the risk of developing brain malignancies and leukemia in exposed pediatric patients. Many efforts have been made to limit the use of CT in children with head injuries. Aim of the Work Our aim was to evaluate the role of skull ultrasound in detection of skull fractures children younger than two years old with closed head injuries. Patients and Methods Type of study was a prospective observational study, sampling method was convenient sampling. The study was conducted according to the stipulations of the Ain Shams University (ASU) ethical and scientific committee. The privacy of participants and confidentiality of data was guaranteed during the various phases of the study. The study was conducted at the radiology unit, Emergency Department, ASU Hospital. The main source of data for this study was patients referred to the Emergency department. Children younger than 2 years presenting with closed head injuries and referred to the radiology department, ASU hospital to perform CT brain, Study Period: 6 months, onset in March 2020. Results We found that skull ultrasound examination of pediatric patients with closed head injuries and Glasgow coma scale (GCS) of 14-15 have a high sensitivity and specificity in detecting skull fractures and subsequently prediction of an underlying traumatic brain injury (TBI) in these patients. Ultrasonographic assessment of the whole cranial vault is not always feasible as most of these age group patients are excessively crying and irritable at presentation, applying the ultrasound probe makes them more irritable and are difficult to maintain their head position during the scan. Although head CT is the gold standard diagnostic modality in the setting of head trauma, it exposes patients to significant ionizing radiation, ultrasonography is a safe diagnostic modality and doesn’t expose the patient to ionizing radiation. Conclusion Skull ultrasound in the setting of pediatrics mild closed head injuries is feasible, safe, sensitive and specific. It can play a complementary rule in risk stratification of these patients.

Early Decompressive Craniectomy: A Life Saving Option in Closed Head Trauma

Aim: To determine outcome and factors associated with outcome among patients with closed head injury who underwent decompressive craniectomy. Methodology: Cross sectional analytical study conducted in Neurosurgery Department of teaching hospital Dera Ghazi Khan from January, 2021 to June, 2021. Total 105 patients fulfilling the inclusion criteria were enrolled in the study. Approval of ethical review committee was obtained. All the patients with closed head injury which underwent decompressive craniectomy were included. Socio demographic profile, mode of injury, Glasgow Coma Scale (GCS) at admission time, pupillary reaction and timing from hospital admission to surgery, duration of surgery, length of hospital stay and occurrence of CSF leakage was noted. SPSS version 22 was used for data entry and analysis. Results: Head injury was more common in males. 43.8% cases admitted with GCS score between 3-8 and with head injury by road traffic accident. Leakage of CSF was recorded in 13.3% patients. Mortality was recorded in 18.1% patients. GCS at time of admission, time elapsed between admission and surgery and duration of surgery was significantly associated with the outcome. Conclusion: Early decompressive craniectomy significantly reduce death rate in patients with closed head injury. Keywords: Craniectomy, Outcome, Glasgow coma scale

Repetitive Mild Traumatic Brain Injury in Rats Impairs Cognition, Enhances Prefrontal Cortex Neuronal Activity, and Reduces Pre-synaptic Mitochondrial Function

A major hurdle preventing effective interventions for patients with mild traumatic brain injury (mTBI) is the lack of known mechanisms for the long-term cognitive impairment that follows mTBI. The closed head impact model of repeated engineered rotational acceleration (rCHIMERA), a non-surgical animal model of repeated mTBI (rmTBI), mimics key features of rmTBI in humans. Using the rCHIMERA in rats, this study was designed to characterize rmTBI-induced behavioral disruption, underlying electrophysiological changes in the medial prefrontal cortex (mPFC), and associated mitochondrial dysfunction. Rats received 6 closed-head impacts over 2 days at 2 Joules of energy. Behavioral testing included automated analysis of behavior in open field and home-cage environments, rotarod test for motor skills, novel object recognition, and fear conditioning. Following rmTBI, rats spent less time grooming and less time in the center of the open field arena. Rats in their home cage had reduced inactivity time 1 week after mTBI and increased exploration time 1 month after injury. Impaired associative fear learning and memory in fear conditioning test, and reduced short-term memory in novel object recognition test were found 4 weeks after rmTBI. Single-unit in vivo recordings showed increased neuronal activity in the mPFC after rmTBI, partially attributable to neuronal disinhibition from reduced inhibitory synaptic transmission, possibly secondary to impaired mitochondrial function. These findings help validate this rat rmTBI model as replicating clinical features, and point to impaired mitochondrial functions after injury as causing imbalanced synaptic transmission and consequent impaired long-term cognitive dysfunction.

Chronic and progressive deficits after a single closed head injury in mice

Background: Acute injury following brain trauma may evolve into a chronic and progressive disorder. Assessment of chronic consequences of TBI must distinguish between effects of age and injury. Methods: C57BL/6 mice receive single closed head injury (CHI) and are analyzed at 14DPI or 180DPI for cortical atrophy and 7DPI or 180DPI for behavioral outcomes. Results: CHI induces ipsilesional atrophy at 14DPI that increases 180 DPI due to an effect of age. On open field, injured mice develop a turn bias at 180DPI not present at 7DPI. On rotarod, injured mice have shorter latencies at 7DPI, but not at 180DPI due to worsening performance of aging uninjured mice. On beam walk, both groups at 180DPI more slowly traverse a 2cm and 1cm beam than at 7DPI. Foot-faults show no significant effects of age or injury. Limb position was assessed using DeeplabcutTM markerless tracking followed by computation of absition (integral of limb displacement over time) using custom Python scripts. On the 2cm beam, age increased absition in all limbs of uninjured mice and both forelimbs of injured mice. Injury increased left hindlimb absition at 7DPI. On the 1cm beam both forelimbs and the left hindlimb of injured mice at 180DPI have larger absition than uninjured mice at 180DPI or injured mice at 7DPI. These data suggest chronic and progressive motor deficits of injured mice at 180DPI. Conclusions: A single impact produces ipsilesional cortical atrophy and chronic and progressive motor deficits. Quantitative behavioral analysis reveals deficits not seen using standard outcomes.

Persistent CO2 reactivity deficits are associated with neurological dysfunction up to one year after repetitive mild closed head injury in adolescent mice

Cerebrovascular reactivity (CVR) deficits in adolescents with concussion may persist after resolution of neurological symptoms. Whether or not CVR deficits predict long term neurological function is unknown. We used adolescent mice closed head injury (CHI) models (54 g, 107 cm or 117 cm drop height), followed by blood oxygenation level dependent (BOLD)-functional MRI with CO2 challenge to assess CVR and brain connectivity. At one week, 3HD 107 cm mice showed delayed BOLD responses (p = 0.0074), normal striatal connectivity, and an impaired respiratory rate response to CO2 challenge (p = 0.0061 in ΔRmax). The 107 cm group developed rotarod deficits at 6 months (p = 0.02) and altered post-CO2 brain connectivity (3-fold increase in striatum to motor cortex correlation coefficient) by one year, but resolved their CVR and respiratory rate impairments, and did not develop cognitive or circadian activity deficits. In contrast, the 117 cm group had persistent CVR (delay time: p = 0.016; washout time: p = 0.039) and circadian activity deficits (free-running period: 23.7 hr in sham vs 23.9 hr in 3HD; amplitude: 0.15 in sham vs 0.2 in 3HD; peak activity: 18 in sham vs 21 in 3HD) at one year. Persistent CVR deficits after concussion may portend long-term neurological dysfunction. Further studies are warranted to determine the utility of CVR to predict chronic neurological outcome after mild traumatic brain injury.