Prediction of outcome after traumatic brain injury using clinical and neuroimaging variables

External validation of the GCS-Pupils Score as an outcome predictor after traumatic brain injury in adults: a single-center experience

OBJECTIVE

The GCS-Pupils (GCS-P) score is a recently described scoring system to aid outcome prediction in patients with traumatic brain injury (TBI). The aim of this study was to provide the first external validation of the GCS-P score by identifying independent predictors of outcome in TBI patients.

METHODS

Review of prospective adult (≥ 16 years) TBI database at a tertiary neurosurgical center with a catchment population of 1.5 million over a 12-month period commencing October 2016. Multivariate logistic regression was used to identify predictors of discharge destination and 30-day mortality.

RESULTS

Three hundred and fifty-eight patients were included. The median age was 60 years with a male predominance of 64%. The median GCS-P was 14 (interquartile range 12-15) and the commonest GCS-P category was mild (13-15; 238/358, 66%). Discharge destination was home in 69% of patients and rehab services or equivalent in 31%. Multivariate analysis identified age (p = 0.01), CT findings of an acute subdural hematoma (p = 0.01) or diffuse axonal injury (p = 0.02), and a neurosurgical operation (p = 0.02) as independent predictors of discharge destination. The 30-day mortality rate was 11%. Within the category of severe TBI (GCS-P ≤ 8), GCS-P was able to identify patients with a very high likelihood of 30-day mortality (GCS-P ≤ 4; 16/31, 52%). Multivariate analysis revealed the Charlson comorbidity score (p = 0.01), GCS-P (p = 0.02), and traumatic subarachnoid hemorrhage (p = 0.05) as independent predictors of mortality.

CONCLUSION

The GCS-P is a useful predictor of 30-day mortality, although its usefulness for other clinical outcomes remains to be proven.

Traumatic brain injury in pregnancy: A systematic review of epidemiology, management, and outcome

OBJECTIVE

Traumatic brain injury (TBI) during pregnancy is an extremely rare condition in our neurosurgical emergency practices. Studies on the epidemiology and management of TBI in pregnancy are limited to case reports or serial case reports. There is no specific guidelines of management of TBI in pregnancy yet.

METHODS

The authors performed a structured search of all published articles on TBI in pregnancy from 1990 to 2020. We restricted search for papers in English and Bahasa.

RESULTS

The literature search yielded 22 articles with total 43 patients. We distinguished C-section based on its timing according to the neurosurgical treatment into primary (simultaneous or prior to neurosurgery) and secondary group (delayed C-section). The mean GOS value in primary C-section is better compared to secondary C-section in severe TBI group (3.57 ± 1.47 vs 3.0 ± 1.27, respectively) consistently in the moderate TBI group (4.33 ± 1.11 vs 3.62 ± 1.47, respectively). The fetal death rate in primary C-section is lower compared to secondary C-section in severe TBI group (14.2 % vs 33.3 %, respectively), contrary, in moderate TBI group (16.7 % vs 12.5 %, respectively).

CONCLUSIONS

Care of pregnant patients with TBI often requires multidisciplinary approach to optimize treatment strategy on a case-by-case basis in light of prior experience across different center. We propose management guideline for head injury in pregnancy.

Community reintegration of people with traumatic brain injury in South Africa

BACKGROUND

Traumatic brain injury (TBI) affects cognitive, behavioral and physical function, influencing community reintegration.

OBJECTIVES

To describe the level of community reintegration and the associated influencing factors post-TBI in South Africa.

METHODS

A cross-sectional analysis of patients living with TBI was done, using the Community Integration Questionnaire (CIQ), the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0), and the Quality of Life after Brain Injury Overall Score (QOLIBRI-OS).

RESULTS

Of the 80 participants 54.0% presented with mild TBI. The median (IQR) score of the CIQ, WHODAS 2.0 and QOLIBRI-OS was 22 (7.5)/29, 31(18)/100 and 73 (45.5)/100. There was a moderate inverse relationship between the WHODAS 2.0 and CIQ scores (r = -0.68; p < 0.001) and a moderate positive correlation between the QOLIBRI-OS and CIQ scores (r = 0.54; p < 0.001). The WHODAS 2.0 scores also showed a strong inverse correlation with the QOLIBRI-OS scores (r = -0.76; p < 0.001).

CONCLUSION

The participants had high levels of functioning and low levels of disability, both of which were found to be in tandem with high CIQ scores and generally good quality of life. Post-TBI patients are capable of achieving good community integration provided they attain high levels of functioning.

The Effectiveness of Dedicated Trauma Operation Theatre and Trauma Intensive Care Unit on the Outcomes of Patients with Traumatic Brain Injury after Emergency Neurosurgery

Background

A dedicated trauma operation theatre (TOT) and a trauma intensive care unit (TICU) within the same block as the emergency department (ED) can facilitate immediate management and surgery of patients suffering from traumatic brain injury (TBI). The present study compared the effectiveness and outcomes of TBI management between the TOT-TICU and general OT (GOT) and neuro-ICU (NICU) setups.

Methods

This was a retrospective cohort study involving 120 patients with TBI who were divided into the GOT-NICU (n = 63) and TOT-TICU (n = 57) groups. Data were obtained from patients' admission and medical records. Demographic data, durations of specific management phases and outcomes of patients were documented.

Results

In the TOT-TICU group, the duration of transportation from ED to OT [15 (standard deviation [SD] = 15) min versus 45 (SD = 15) min; P < 0.001], duration of arrival in OT to incision [50 (SD = 30) versus 70 (SD = 23) min; P = 0.005] and duration of transportation from OT to ICU [40 (SD = 17) versus 48 (SD = 30); P = 0.005] were significantly shorter than those in the GOT-NICU group. However, the duration of mechanical ventilation, duration of ICU stays, Glasgow Outcome Scale (GOS) upon discharge and GOS at 3-month post-discharge were comparable between both groups.

Conclusion

The TOT-TICU setup shortened the duration of transportation from ED to OT, duration of arrival in OT to incision and duration of transportation from OT to ICU compared with the GOT-NICU setup. Hence, the availability of OT and ICU within the trauma block managed to provide immediate management to TBI patients.

Analysis of the Association Between Lung Function and Brain Tissue Oxygen Tension in Severe Traumatic Brain Injury

INTRODUCTION

Low brain tissue oxygen tension (PbtO₂) has been shown to be an independent factor associated with unfavourable outcomes in traumatic brain injury (TBI). Although PbtO₂ provides clinicians with an understanding of ischaemic and non-ischaemic derangements of brain physiology, the value alone can be the result of several factors, including partial arterial oxygenation pressure (PaO₂), haemoglobin levels (Hb) and cerebral perfusion pressure (CPP).

METHODS

This chapter presents a single-centre, retrospective cohort study of 70 adult patients with severe TBI who were admitted to the Neurocritical Care Unit (NCCU) at Addenbrooke's Hospital (Cambridge, UK) between October 2014 and December 2017. A total of 303 simultaneous measurements of different variables that included (but were not limited to) intracranial pressure (ICP), PaO₂, PbtO₂, CPP and the fraction of inspired oxygen (FiO₂) were considered in this work. We conducted a correlation analysis between all of the variables. We also implemented a longitudinal data analysis of the PbtO₂ and PaO₂/FiO₂ ratio (PF ratio).

RESULTS

There were strong and independent correlations between PbtO₂ and the PF ratio, and between PbtO₂ and PaO₂, with adjusted p values of <0.001 for both correlations. After adjustment for ICP, age, sex and the Glasgow Coma Scale (GCS) score, a PF ≤ 330 was shown to be an independent risk factor for a compromised PbtO₂ value of <20, with an adjusted odds ratio of 1.94 (95% confidence interval 1.12-3.34) and a p value of 0.02.

CONCLUSION

Brain and lung interactions in patients with TBI patients have complex interrelationships. Our results confirm the importance of employing lung-protective strategies to prevent brain hypoxia in patients with TBI.

Identification of predictive MRI and functional biomarkers in a pediatric piglet traumatic brain injury model

Traumatic brain injury (TBI) at a young age can lead to the development of long-term functional impairments. Severity of injury is well demonstrated to have a strong influence on the extent of functional impairments; however, identification of specific magnetic resonance imaging (MRI) biomarkers that are most reflective of injury severity and functional prognosis remain elusive. Therefore, the objective of this study was to utilize advanced statistical approaches to identify clinically relevant MRI biomarkers and predict functional outcomes using MRI metrics in a translational large animal piglet TBI model. TBI was induced via controlled cortical impact and multiparametric MRI was performed at 24 hours and 12 weeks post-TBI using T1-weighted, T2-weighted, T2-weighted fluid attenuated inversion recovery, diffusion-weighted imaging, and diffusion tensor imaging. Changes in spatiotemporal gait parameters were also assessed using an automated gait mat at 24 hours and 12 weeks post-TBI. Principal component analysis was performed to determine the MRI metrics and spatiotemporal gait parameters that explain the largest sources of variation within the datasets. We found that linear combinations of lesion size and midline shift acquired using T2-weighted imaging explained most of the variability of the data at both 24 hours and 12 weeks post-TBI. In addition, linear combinations of velocity, cadence, and stride length were found to explain most of the gait data variability at 24 hours and 12 weeks post-TBI. Linear regression analysis was performed to determine if MRI metrics are predictive of changes in gait. We found that both lesion size and midline shift are significantly correlated with decreases in stride and step length. These results from this study provide an important first step at identifying relevant MRI and functional biomarkers that are predictive of functional outcomes in a clinically relevant piglet TBI model. This study was approved by the University of Georgia Institutional Animal Care and Use Committee (AUP: A2015 11-001) on December 22, 2015.

Lung Injury Is a Predictor of Cerebral Hypoxia and Mortality in Traumatic Brain Injury

Background: A major contributor to unfavorable outcome after traumatic brain injury (TBI) is secondary brain injury. Low brain tissue oxygen tension (PbtO2) has shown to be an independent predictor of unfavorable outcome. Although PbtO2 provides clinicians with an understanding of the ischemic and non-ischemic derangements of brain physiology, its value does not take into consideration systemic oxygenation that can influence patients' outcomes. This study analyses brain and systemic oxygenation and a number of related indices in TBI patients: PbtO2, partial arterial oxygenation pressure (PaO2), PbtO2/PaO2, ratio of PbtO2 to fraction of inspired oxygen (FiO2), and PaO2/FiO2. The primary aim of this study was to identify independent risk factors for cerebral hypoxia. Secondary goal was to determine whether any of these indices are predictors of mortality outcome in TBI patients. Materials and Methods: A single-centre retrospective cohort study of 70 TBI patients admitted to the Neurocritical Care Unit (NCCU) at Cambridge University Hospital in 2014-2018 and undergoing advanced neuromonitoring including invasive PbtO2 was conducted. Three hundred and three simultaneous measurements of PbtO2, PaO2, PbtO2/PaO2, PbtO2/FiO2, PaO2/FiO2 were collected and mortality at discharge from NCCU was considered as outcome. Generalized estimating equations were used to analyse the longitudinal data. Results: Our results showed PbtO2 of 28 mmHg as threshold to define cerebral hypoxia. PaO2/FiO2 found to be a strong and independent risk factor for cerebral hypoxia when adjusting for confounding factor of intracranial pressure (ICP) with adjusted odds ratio of 1.78, 95% confidence interval of (1.10-2.87) and p-value = 0.019. With respect to TBI outcome, compromised values of PbtO2, PbtO2/PaO2, PbtO2/FiO2, and PaO2/FiO2 were all independent predictors of mortality while considered individually and adjusting for confounding factors of ICP, age, gender, and cerebral perfusion pressure (CPP). However, when considering all the compromised values together, only PaO2/FiO2 became an independent predictor of mortality with adjusted odds ratio of 3.47 (1.20-10.04) and p-value = 0.022. Conclusions: Brain and Lung interaction in TBI patients is a complex interrelationship. PaO2/FiO2 seems to be a major determinant of cerebral hypoxia and mortality. These results confirm the importance of employing ventilator strategies to prevent cerebral hypoxia and improve the outcome in TBI patients.

Phosphorus spectroscopy in acute TBI demonstrates metabolic changes that relate to outcome in the presence of normal structural MRI

Metabolic dysfunction is a key pathophysiological process in the acute phase of traumatic brain injury (TBI). Although changes in brain glucose metabolism and extracellular lactate/pyruvate ratio are well known, it was hitherto unknown whether these translate to downstream changes in ATP metabolism and intracellular pH. We have performed the first clinical voxel-based in vivo phosphorus magnetic resonance spectroscopy (³¹P MRS) in 13 acute-phase major TBI patients versus 10 healthy controls (HCs), at 3T, focusing on eight central 2.5 × 2.5 × 2.5 cm³ voxels per subject. PCr/γATP ratio (a measure of energy status) in TBI patients was significantly higher (median = 1.09) than that of HCs (median = 0.93) (p < 0.0001), due to changes in both PCr and ATP. There was no significant difference in PCr/γATP between TBI patients with favourable and unfavourable outcome. Cerebral intracellular pH of TBI patients was significantly higher (median = 7.04) than that of HCs (median = 7.00) (p = 0.04). Alkalosis was limited to patients with unfavourable outcome (median = 7.07) (p < 0.0001). These changes persisted after excluding voxels with > 5% radiologically visible injury. This is the first clinical demonstration of brain alkalosis and elevated PCr/γATP ratio acutely after major TBI. ³¹P MRS has potential for non-invasively assessing brain injury in the absence of structural injury, predicting outcome and monitoring therapy response.

Diffuse axonal injury after traumatic brain injury is a prognostic factor for functional outcome: a systematic review and meta-analysis

OBJECTIVE

To determine the prognosis of adult patients with traumatic brain injury (TBI) and diffuse axonal injury (DAI).

METHODS

Online search (PubMed, Embase and Ovid Science Direct) of articles providing information about outcome in (1) patients with DAI in general, (2) DAI vs. non-DAI, (3) related to magnetic resonance imaging (MRI) classification and (4) related to lesion location/load. A reference check and quality assessment were performed.

RESULTS

A total of 32 articles were included. TBI patients with DAI had a favourable outcome in 62%. The risk of unfavourable outcome in TBI with DAI was three times higher than in TBI without DAI. Odds ratio (OR) for unfavourable outcome was 2.9 per increase of DAI grade on MRI. Lesions located in the corpus callosum were associated with an unfavourable outcome. Other specific lesion locations and lesions count showed inconsistent results regarding outcome. Lesion volume was predictive for outcome only on apparent diffusion coefficient and fluid attenuation inversion recovery MRI sequences.

CONCLUSIONS

Presence of DAI on MRI in patients with TBI results in a higher chance of unfavourable outcome. With MRI grading, OR for unfavourable outcome increases threefold with every grade. Lesions in the corpus callosum in particular are associated with an unfavourable outcome.

Knockout of Cyclophilin-D Provides Partial Amelioration of Intrinsic and Synaptic Properties Altered by Mild Traumatic Brain Injury

Mitochondria are central to cell survival and Ca²⁺ homeostasis due to their intracellular buffering capabilities. Mitochondrial dysfunction resulting in mitochondrial permeability transition pore (mPTP) opening has been reported after mild traumatic brain injury (mTBI). Cyclosporine A provides protection against the mPTP opening through its interaction with cyclophilin-D (CypD). A recent study has found that the extent of axonal injury after mTBI was diminished in neocortex in cyclophilin-D knockout (CypDKO) mice. Here we tested whether this CypDKO could also provide protection from the increased intrinsic and synaptic neuronal excitability previously described after mTBI in a mild central fluid percussion injury mice model. CypDKO mice were crossed with mice expressing yellow fluorescent protein (YFP) in layer V pyramidal neurons in neocortex to create CypDKO/YFP-H mice. Whole cell patch clamp recordings from axotomized (AX) and intact (IN) YFP+ layer V pyramidal neurons were made 1 and 2 days after sham or mTBI in slices from CypDKO/YFP-H mice. Both excitatory post synaptic currents (EPSCs) recorded in voltage clamp and intrinsic cellular properties, including action potential (AP), afterhyperpolarization (AHP), and depolarizing after potential (DAP) characteristics recorded in current clamp were evaluated. There was no significant difference between sham and mTBI for either spontaneous or miniature EPSC frequency, suggesting that CypDKO ameliorates excitatory synaptic abnormalities. There was a partial amelioration of intrinsic properties altered by mTBI. Alleviated were the increased slope of the AP frequency vs. injected current plot, the increased AP, AHP and DAP amplitudes. Other properties that saw a reversal that became significant in the opposite direction include the current rheobase and AP overshoot. The AP threshold remained depolarized and the input resistance remained increased in mTBI compared to sham. Additional altered properties suggest that the CypDKO likely has a direct effect on membrane properties, rather than producing a selective reduction of the effects of mTBI. These results suggest that inhibiting CypD after TBI is an effective strategy to reduce synaptic hyperexcitation, making it a continued target for potential treatment of network abnormalities.

Intrinsic Functional Connectivity Patterns Predict Consciousness Level and Recovery Outcome in Acquired Brain Injury

For accurate diagnosis and prognostic prediction of acquired brain injury (ABI), it is crucial to understand the neurobiological mechanisms underlying loss of consciousness. However, there is no consensus on which regions and networks act as biomarkers for consciousness level and recovery outcome in ABI. Using resting-state fMRI, we assessed intrinsic functional connectivity strength (FCS) of whole-brain networks in a large sample of 99 ABI patients with varying degrees of consciousness loss (including fully preserved consciousness state, minimally conscious state, unresponsive wakefulness syndrome/vegetative state, and coma) and 34 healthy control subjects. Consciousness level was evaluated using the Glasgow Coma Scale and Coma Recovery Scale-Revised on the day of fMRI scanning; recovery outcome was assessed using the Glasgow Outcome Scale 3 months after the fMRI scanning. One-way ANOVA of FCS, Spearman correlation analyses between FCS and the consciousness level and recovery outcome, and FCS-based multivariate pattern analysis were performed. We found decreased FCS with loss of consciousness primarily distributed in the posterior cingulate cortex/precuneus (PCC/PCU), medial prefrontal cortex, and lateral parietal cortex. The FCS values of these regions were significantly correlated with consciousness level and recovery outcome. Multivariate support vector machine discrimination analysis revealed that the FCS patterns predicted whether patients with unresponsive wakefulness syndrome/vegetative state and coma would regain consciousness with an accuracy of 81.25%, and the most discriminative region was the PCC/PCU. These findings suggest that intrinsic functional connectivity patterns of the human posteromedial cortex could serve as a potential indicator for consciousness level and recovery outcome in individuals with ABI.

SIGNIFICANCE STATEMENT

Varying degrees of consciousness loss and recovery are commonly observed in acquired brain injury patients, yet the underlying neurobiological mechanisms remain elusive. Using a large sample of patients with varying degrees of consciousness loss, we demonstrate that intrinsic functional connectivity strength in many brain regions, especially in the posterior cingulate cortex and precuneus, significantly correlated with consciousness level and recovery outcome. We further demonstrate that the functional connectivity pattern of these regions can predict patients with unresponsive wakefulness syndrome/vegetative state and coma would regain consciousness with an accuracy of 81.25%. Our study thus provides potentially important biomarkers of acquired brain injury in clinical diagnosis, prediction of recovery outcome, and decision making for treatment strategies for patients with severe loss of consciousness.

Contribution of psychological trauma to outcomes after traumatic brain injury: assaults versus sporting injuries

Clinical research into outcomes after traumatic brain injury (TBI) frequently combines injuries that have been sustained through different causes (e.g., car accidents, assaults, and falls), the effect of which is not well understood. This study examined the contribution of injury-related psychological trauma—which is more commonly associated with specific types of injuries—to outcomes after nonpenetrating TBI in order to determine whether it may be having a differential effect in samples containing mixed injuries. Data from three groups that were prospectively recruited for two larger studies were compared: one that sustained a TBI as a result of physical assaults (i.e., psychologically traumatizing) and another as a result of sporting injuries (i.e., nonpsychologically traumatizing), as well as an orthopedic control group (OC). Psychosocial and emotional (postconcussion symptoms, injury-related stress, and depression), cognitive (memory, abstract reasoning, problem solving, and verbal fluency), and functional (general outcome; resumption of home, social, and work roles) outcomes were all assessed. The TBI(assault) group reported significantly poorer psychosocial and emotional outcomes and higher rates of litigation (criminal rather than civil) than both the TBI(sport) and OC groups approximately 6 months postinjury, but there were no differences in the cognitive or functional outcomes of the three groups. The findings suggest that the cause of a TBI may assist in explaining some of the differences in outcomes of people who have seemingly comparable injuries. Involvement in litigation and the cause of an injury may also be confounded, which may lead to the erroneous conclusion that litigants have poorer outcomes.

Prognostic value of early magnetic resonance imaging in dogs after traumatic brain injury: 50 cases

BACKGROUND

The prognostic value of early magnetic resonance imaging (MRI) in dogs after traumatic brain injury (TBI) remains unclear.

OBJECTIVES

Determine whether MRI findings are associated with prognosis after TBI in dogs.

ANIMALS

Fifty client-owned dogs.

METHODS

Retrospective study of dogs with TBI that underwent 1.5T MRI within 14 days after head trauma. MRI evaluators were blinded to the clinical presentation, and all images were scored based on an MRI grading system (Grade I [normal brain parenchyma] to Grade VI [bilateral lesions affecting the brainstem with or without any lesions of lesser grade]). Skull fractures, percentage of intraparenchymal lesions, degree of midline shift, and type of brain herniation were evaluated. MGCS was assessed at presentation. The presence of seizures was recorded. Outcome was assessed at 48 h (alive or dead) and at 3, 6, 12, and 24 months after TBI.

RESULTS

Sixty-six percent of the dogs had abnormal MRI findings. MRI grade was negatively correlated (P < .001) with MGCS. A significant negative correlation of MRI grade, degree of midline shift, and percentage of intraparenchymal lesions with follow-up scores was identified. The MGCS was lower in dogs with brain herniation (P = .0191). Follow-up scores were significantly lower in dogs that had brain herniation or skull fractures. The possibility of having seizures was associated with higher percentage of intraparenchymal lesions (P = 0.0054) and 10% developed PTE.

CONCLUSIONS AND CLINICAL IMPORTANCE

Significant associations exist between MRI findings and prognosis in dogs with TBI. MRI can help to predict prognosis in dogs with TBI.

High-level mobility in chronic traumatic brain injury and its relationship with clinical variables and magnetic resonance imaging findings in the acute phase

OBJECTIVES

To compare high-level mobility in individuals with chronic moderate-to-severe traumatic brain injury (TBI) with matched healthy controls, and to investigate whether clinical variables and magnetic resonance imaging (MRI) findings in the acute phase can predict high-level motor performance in the chronic phase.

DESIGN

A longitudinal follow-up study.

SETTING

A level 1 trauma center.

PARTICIPANTS

Individuals (N=136) with chronic TBI (n=65) and healthy matched peers (n=71).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

High-Level Mobility Assessment Tool (HiMAT) and the revised version of the HiMAT performed at a mean of 2.8 years (range, 1.5-5.4y) after injury.

RESULTS

Participants with chronic TBI had a mean HiMAT score of 42.7 (95% confidence interval [CI], 40.2-45.2) compared with 47.7 (95% CI, 46.1-49.2) in the control group (P<.01). Group differences were also evident using the revised HiMAT (P<.01). Acute-phase clinical variables and MRI findings explained 58.8% of the variance in the HiMAT score (P<.001) and 59.9% in the revised HiMAT score (P<.001). Lower HiMAT scores were associated with female sex (P=.031), higher age at injury (P<.001), motor vehicle collisions (P=.030), and posttraumatic amnesia >7 days (P=.048). There was a tendency toward an association between lower scores and diffuse axonal injury in the brainstem (P=.075).

CONCLUSIONS

High-level mobility was reduced in participants with chronic, either moderate or severe TBI compared with matched peers. Clinical variables in the acute phase were significantly associated with high-level mobility performance in participants with TBI, but the role of early MRI findings needs to be further investigated. The findings of this study suggest that the clinical variables in the acute phase may be useful in predicting high-level mobility outcome in the chronic phase.