A State-of-the-Science Overview of Randomized Controlled Trials Evaluating Acute Management of Moderate-to-Severe Traumatic Brain Injury

Recovery Potential in Patients Who Died After Withdrawal of Life-Sustaining Treatment: A TRACK-TBI Propensity Score Analysis

Among patients with severe traumatic brain injury (TBI), there is high prognostic uncertainty but growing evidence that recovery of independence is possible. Nevertheless, families are often asked to make decisions about withdrawal of life-sustaining treatment (WLST) within days of injury. The range of potential outcomes for patients who died after WLST (WLST+) is unknown, posing a challenge for prognostic modeling and clinical counseling. We investigated the potential for survival and recovery of independence after acute TBI in patients who died after WLST. We used Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) data and propensity score matching to pair participants with WLST+ to those with a similar probability of WLST (based on demographic and clinical characteristics), but for whom life-sustaining treatment was not withdrawn (WLST-). To optimize matching, we divided the WLST- cohort into tiers (Tier 1 = 0-11%, Tier 2 = 11-27%, Tier 3 = 27-70% WLST propensity). We estimated the level of recovery that could be expected in WLST+ participants by evaluating 3-, 6-, and 12-month Glasgow Outcome Scale-Extended (GOSE) and Disability Rating Scale outcomes in matched WLST- participants. Of 90 WLST+ participants (80% male, mean [standard deviation; SD] age = 59.2 [17.9] years, median [IQR] days to WLST = 5.4 [2.2, 11.7]), 80 could be matched to WLST- participants. Of 56 WLST- participants who were followed at 6 months, 31 (55%) died. Among survivors in the overall sample and survivors in Tiers 1 and 2, more than 30% recovered at least partial independence (GOSE ≥4). In Tier 3, recovery to GOSE ≥4 occurred at 12 months, but not 6 months, post-injury. These results suggest a substantial proportion of patients with TBI and WLST may have survived and achieved at least partial independence. However, death or severe disability is a common outcome when the probability of WLST is high. While further validation is needed, our findings support a more cautious clinical approach to WLST and more complete reporting on WLST in TBI studies.

A Systematic Review of Reported Outcomes in Randomized Controlled Trials Targeting Early Interventions in Moderate-to-Severe Traumatic Brain Injury

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Randomized controlled trials (RCTs) are the cornerstone to evaluate the efficacy of an intervention. To assess the methodology of clinical research, we performed a systematic review that evaluated the different outcomes used in RCTs targeting the early phase of moderate-to-severe adult TBI from 1983 to October 31, 2023. We extracted each outcome and organized them according to the COMET and OMERACT framework (core area, broad domains, target domains, and finally outcomes). A total of 190 RCTs were included, including 52,010 participants. A total of 557 outcomes were reported and classified between the following core areas: pathophysiological manifestations [169 RCTs (88.9%)], life impact [117 RCTs (61.6%)], death [94 RCTs (49.5%)], resource use [72 RCTs (37.9%)], and adverse events [41 RCTs (21.6%)]. We identified 29 broad domains and 89 target domains. Among target domains, physical functioning [111 (58.4%)], mortality [94 (49.5%)], intracranial pressure target domain [68 (35.8%)], and hemodynamics [53 (27.9%)] were the most frequent. Outcomes were mostly clinician-reported [177 (93.2%)], while patient-reported outcomes were rarely reported [11 (5.8%)]. In our review, there was significant heterogeneity in the choice of end-points in TBI clinical research. There is an urgent need for consensus and homogeneity to improve the quality of clinical research in this area.

dTBI2: A Calibrated, Tunable Device for Administering Traumatic Brain Injury in Drosophila

The second-generation Drosophila traumatic brain injury (TBI) device dTBI2 improves Drosophila TBI administration by providing a moderate-throughput, tunable, head-specific injury. Our updated device design improves user-friendliness, eliminates inconsistencies in injury timing, and has an updated circuit design to extend the longevity of delicate electronic components. dTBI2 improves reproducibility across users and runs, and results in more consistent post-injury phenotypes. This protocol describes the construction, calibration, and use of the dTBI2 device, which uses an Arduino-controlled piezoelectric actuator to deliver a force that compresses a fly head against a metal collar. The duration and depth of head compression is tunable, allowing calibration of injury severity. All device components are commercially available, and the entire device can be constructed in under a week for less than $1000. The dTBI2 design will enable any lab to build a highly reliable, low-cost device for Drosophila TBI, facilitating increased adoption and ease of exploration of closed-head TBI in Drosophila for forward genetic screens. We describe below the three protocols necessary for constructing a dTBI2 device. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Construction of the dTBI2 control device Basic Protocol 2: Construction of the piezoelectric actuator housing Basic Protocol 3: Administration of dTBI2 injuries.

Comparative Effectiveness of Early Neurosurgical Intervention in Civilian Penetrating Brain Injury Management

BACKGROUND AND OBJECTIVES

To compare the outcomes of early vs no-neurosurgical intervention in civilians with penetrating brain injury (PBI).

METHODS

We collected data from the National Trauma Data Bank for PBI between 2017 and 2019. A total of 10 607 cases were identified; 1276 cases met the following criteria: age 16-60 years, an intensive care unit (ICU) length of stay (LOS) of >2 days, a Glasgow Coma Scale of 3-12, and at least one reactive pupil on presentation. Patients with withdrawal of life-sustaining treatments within 72 hours were excluded, leaving 1231 patients for analysis. Neurosurgical intervention was defined as an open-approach cranial procedure involving release, drainage, or extirpation of brain matter performed within 24 hours. Outcomes of interest were mortality, withdrawal of life-sustaining treatments, ICU LOS, and dispositional outcome.

RESULTS

The target population was 1231 patients (84.4% male; median [IQR] age, 29 [18] years); 267 (21.7%) died, and 364 (29.6%) had a neurosurgical intervention within the first 24 hours. 1:1 matching yielded 704 patients (352 in each arm). In the matched cohort (mortality 22.6%), 64 patients who received surgery (18.2%) died compared with 95 (27%) in the nonsurgical group. Survival was more likely in the surgical group (odds ratio [OR] 1.66, CI 1.16-2.38, P < .01; number needed to treat 11). Dispositional outcome was not different. Overlap propensity score-weighted analysis (1231 patients) resulted in higher odds of survival in the surgical group (OR 1.8, CI 1.16-2.80, P < .01). The E-value for the OR calculated from the matched data set was 2.83. Early neurosurgical intervention was associated with longer ICU LOS (median 12 days [7.0, 19.0 IQR] vs 8 days [4.0, 15.0 IQR], P < .05).

CONCLUSION

Management including early neurosurgical intervention is associated with decreased mortality and increased ICU LOS in matched cohorts of PBI.

Penetrating Firearm-Inflicted Injury-The Neglected Traumatic Brain Injury

This Viewpoint discusses penetrating firearm-inflicted brain injury and the current collaborative efforts to perform more penetrating brain injury–specific randomized clinical trials and comparative effectiveness research to identify effective management guidelines.

ApoE Mimetic Peptides as Therapy for Traumatic Brain Injury

The lack of targeted therapies for traumatic brain injury (TBI) remains a compelling clinical unmet need. Although knowledge of the pathophysiologic cascades involved in TBI has expanded rapidly, the development of novel pharmacological therapies has remained largely stagnant. Difficulties in creating animal models that recapitulate the different facets of clinical TBI pathology and flaws in the design of clinical trials have contributed to the ongoing failures in neuroprotective drug development. Furthermore, multiple pathophysiological mechanisms initiated early after TBI that progress in the subacute and chronic setting may limit the potential of traditional approaches that target a specific cellular pathway for acute therapeutic intervention. We describe a reverse translational approach that focuses on translating endogenous mechanisms known to influence outcomes after TBI to develop druggable targets. In particular, numerous clinical observations have demonstrated an association between apolipoprotein E (apoE) polymorphism and functional recovery after brain injury. ApoE has been shown to mitigate the response to acute brain injury by exerting immunomodulatory properties that reduce secondary tissue injury as well as protecting neurons from excitotoxicity. CN-105 represents an apoE mimetic peptide that can effectively penetrate the CNS compartment and retains the neuroprotective properties of the intact protein.

Management Strategies Based on Multi-Modality Neuromonitoring in Severe Traumatic Brain Injury

Secondary brain injury after neurotrauma is comprised of a host of distinct, potentially concurrent and interacting mechanisms that may exacerbate primary brain insult. Multimodality neuromonitoring is a method of measuring multiple aspects of the brain in order to understand the signatures of these different pathomechanisms and to detect, treat, or prevent potentially reversible secondary brain injuries. The most studied invasive parameters include intracranial pressure (ICP), cerebral perfusion pressure (CPP), autoregulatory indices, brain tissue partial oxygen tension, and tissue energy and metabolism measures such as the lactate pyruvate ratio. Understanding the local metabolic state of brain tissue in order to infer pathology and develop appropriate management strategies is an area of active investigation. Several clinical trials are underway to define the role of brain tissue oxygenation monitoring and electrocorticography in conjunction with other multimodal neuromonitoring information, including ICP and CPP monitoring. Identifying an optimal CPP to guide individualized management of blood pressure and ICP has been shown to be feasible, but definitive clinical trial evidence is still needed. Future work is still needed to define and clinically correlate patterns that emerge from integrated measurements of metabolism, pressure, flow, oxygenation, and electrophysiology. Pathophysiologic targets and precise critical care management strategies to address their underlying causes promise to mitigate secondary injuries and hold the potential to improve patient outcome. Advancements in clinical trial design are poised to establish new standards for the use of multimodality neuromonitoring to guide individualized clinical care.

Protocol for Safety and Efficacy of MLC901 (NeuroAiD II) in Patients With Moderate Traumatic Brain Injury: A Randomized Double-Blind Placebo-Controlled Trial (ANDROMEDA)

BACKGROUND AND OBJECTIVES

Traumatic brain injury (TBI) remains a leading cause of death and disability, affecting approximately 69 million individuals each year worldwide. A significant portion of TBI research has focused on treatments for neuroprotection and/or neurorecovery, with most failing to transition to successful clinical applications despite promising animal/in vitro study results. MLC901 (NeuroAiD II), with origins from a traditional Chinese medicine, has been shown to exhibit both neuroprotective and neuroregenerative properties in in vitro and animal studies for stroke and TBI. Clinical trials have demonstrated its safety with significant improvements in some functional outcome and cognitive domain measures. The objective of this study is to determine the efficacy and safety of MLC901 (NeuroAiD II) vs placebo in adult patients with moderate TBI.

METHODS

This is a multicenter randomized double-blind placebo-controlled trial that aims to enroll 120 adult patients with moderate TBI receiving standard of care in 2 arms: MLC901 vs placebo for a treatment period of 6 months with a further follow-up of 3 months. The total duration of the study is 9 months. The primary end point is Glasgow Outcome Scale Extended (GOS-E) at 6 months. Other assessments include mortality at 6 months, GOS-E, Glasgow Coma Scale, Montreal Cognitive Assessment Filipino Version, Frontal Assessment Battery Conflicting Instructions and Go-No-Go, Rivermead Post-Concussion Symptom Questionnaire, Barthel Index, Hospital Anxiety and Depression Scale, and Health related Quality of life (EQ-5D) at 1, 3, 6, and 9 months. Cerebral swelling at baseline and at 1 and 2 weeks will also be documented. Adverse events and drug compliance will also be monitored.

EXPECTED OUTCOMES

We expect to find a significant improvement in functional and cognitive outcomes in patients who were given MLC901.

DISCUSSION

Previous studies on the effect of MLC901 in adult patients with moderate TBI showed positive results; However, these studies are limited by the small number of patients. This study will establish a more definitive role of MLC901 in improving functional and cognitive outcomes in patients with moderate TBI.

Determining the Minimally Clinically Important Difference for the Disability Rating Scale in Persons With Chronic Traumatic Brain Injury

The Extended Glasgow Outcome Scale (GOSE) is accepted as the primary outcome measure in registrational studies for traumatic brain injury (TBI). The Disability Rating Scale (DRS) is used to assess functional progress from initial acute injury, through rehabilitation and reintegration into the community and life. For these reasons, the DRS is an alternative measure for assessing meaningful global outcomes in chronic TBI. The objective of this study was to determine the minimally clinically important difference (MCID) for the DRS in chronic TBI, by determining the magnitude of DRS change associated with the MCID for the GOSE of 1 point. This study is a retrospective analysis of the multi-center, prospective, longitudinal, Traumatic Brain Injury Model Systems National Database of persons with outcomes at 1, 2, and 5 years and every 5 years thereafter post-injury. Spearman's correlations for dynamic and static relationships between the DRS and GOSE were significant. For the 1-point MCID for the GOSE, the dynamic MCID estimate for the DRS of a -0.68-point change was calculated as the mean DRS change associated with the difference of the GOSE score between year 1 and year 2 (score range, 3-8), using all persons in the study (n = 11,102), whereas the exploratory static MCID estimate for the DRS of -1.28 points was calculated from the slope of the best-fit line between the DRS and GOSE at year 1 follow-up (score range, 3-8; n = 13,415). The final MCID for the DRS was calculated by using the triangulation method (i.e., the arithmetic mean of the dynamic and exploratory static MCID estimates), which resulted in a -1.0-point change. The significant correlation between the DRS and GOSE has allowed for the establishment of a -1.0-point MCID for the DRS, which supports the use of the DRS as an alternative primary outcome measure for chronic TBI research studies, including clinical trials.

[Endovascular Treatment for Head and Neck Trauma]

Trauma to the head and neck region can have serious consequences for vital organs such as the brain, and injuries to blood vessels can cause permanent neurological damage or even death. Thus, prompt treatment of head and neck vessels is crucial. Although the level of evidence is moderate, an increasing amount of research indicates that endovascular treatments can be a viable alternative to traditional surgery or medical management. Embolization or reconstructive endovascular procedures can significantly improve patient outcomes. This article provides an overview of various endovascular options available for specific clinical scenarios, along with examples of cases in which they were employed.

Incidence of acute neurosurgery for traumatic brain injury in children-a nationwide analysis from 1998 to 2018

BACKGROUND

Most of moderate and severe pTBIs are managed conservatively, but in some cases neurosurgical interventions are needed. The incidence rates of acute pTBI neurosurgery vary considerably between countries and operation types. Our goal was to assess the incidence of acute pTBI neurosurgery in Finland.

METHODS

We conducted a retrospective Finnish register-based cohort study from 1998 to 2018. We included all patients that were 0 to 17 years of age at the time of the TBI. The incidence rates of patients with pTBI undergoing neurosurgery and the rates for specific operation types were calculated per 100,000 person-years. We compared the annual incidences with incidence rate ratios (IRR) with 95% confidence intervals (CI). We stratified patients to three age categories: (i) 0 to 3 years of age, (ii) 4 to 12 years of age, and (iii) 13 to 17 years of age.

RESULTS

The total number of neurosurgeries for acute pTBI during the study period was 386, and the cumulative incidence was 1.67 operations per 100,000 person-years. The cumulative incidence during the 21-year follow-up was highest at the age of 16 (IRR 4.78, CI 3.68 to 6.11). Boys had a 2.42-time higher cumulative incidence (IRR 2.35, CI 1.27 to 3.99) than girls (IRR 0.97, CI 0.35 to 2.20). The most common neurosurgery was an evacuation of an intracranial hemorrhage (n = 171; 44.3%).

CONCLUSION

The incidence of neurosurgeries for pTBIs has been stable from 1998 to 2018. The incidence was highest at the age of 16, and boys had higher incidence than girls.

What Happens Next? Traumatic Brain Injury in the Community

Traumatic brain injury (TBI) continues to substantially impact the lives of millions of people around the world annually. Community-based prevention and support of TBI are particularly challenging and underresearched aspects of TBI management. Ongoing cognitive, emotional, and other effects of TBI are not immediately obvious in community settings such as schools, workplaces, sporting clubs, aged care facilities, and support agencies providing homelessness or domestic violence support. This is compounded by a lack of guidance and support materials designed for nonmedical settings. Connectivity Australia, a not-for-profit organization promoting TBI awareness, research, and support, responded to this need by conducting a national survey and series of roundtables to deepen understanding of TBI awareness, challenges, and support needs across the community. The 48 survey respondents and 22 roundtable participants represented Australian departments of health; correctional services; homelessness and housing; Aboriginal and Torres Strait Islander health; community, school, and professional sports; allied healthcare and rehabilitation providers; insurance; and work health and safety. Three key themes were identified: Accessible, nationally consistent plain-language guidelines ; Building research literacy ; and Knowing your role in TBI identification and management . This commentary briefly describes these themes and their implications based on a publicly available full report detailing the study findings ( www.connectivity.org.au/resources-for-researchers/connectivity-research ).

Lower and higher volumes of physical exercise build up brain reserves against memory deficits triggered by a head injury in mice

Decreasing neurotrophic support and impaired mitochondrial bioenergetics are key mechanisms for long-term neurodegeneration and cognitive decline after traumatic brain injury (TBI). We hypothesize that preconditioning with lower and higher volumes of physical exercise upregulates the CREB-BDNF axis and bioenergetic capability, which might serve as neural reserves against cognitive impairment after severe TBI. Using a running wheel mounted in the home cage, mice were engaged in lower (LV, 48 h free access, and 48 h locked) and higher (HV, daily free access) exercise volumes for thirty days. Subsequently, LV and HV mice remained for additional thirty days in the home cage with the running wheel locked and were euthanized. The sedentary group had the running wheel always locked. For the same type of exercise stimulus in a given time, daily workout presents higher volume than alternate days workout. The total distance ran in the wheel was the reference parameter to confirm distinct exercise volumes. On average, LV exercise ran 27.522 m and HV exercise ran 52.076 m. Primarily, we investigate whether LV and HV protocols increase neurotrophic and bioenergetic support in the hippocampus thirty days after exercise ceased. Regardless of volume, exercise increased hippocampal pCREBSer133-CREB-proBDNF-BDNF signaling and mitochondrial coupling efficiency, excess capacity, and leak control, that may compose the neurobiological basis for neural reserves. Further, we challenge these neural reserves against secondary memory deficits triggered by a severe TBI. After thirty days of exercise LV and HV, and sedentary (SED) mice were submitted to the CCI model. Mice remained for additional thirty days in the home cage with the running wheel locked. The mortality after severe TBI was approximately 20% in LV and HV, while in the SED was 40%. Also, LV and HV exercise sustained hippocampal pCREBSer133-CREB-proBDNF-BDNF signaling, mitochondrial coupling efficiency, excess capacity, and leak control for thirty days after severe TBI. Corroborating these benefits, the mitochondrial H2O2 production linked to complexes I and II was attenuated by exercise regardless of the volume. These adaptations attenuated spatial learning and memory deficits caused by TBI. In summary, preconditioning with LV and HV exercise builds up long-lasting CREB-BDNF and bioenergetic neural reserves that preserve memory fitness after severe TBI.

Tackling Neuroinflammation After Traumatic Brain Injury: Complement Inhibition as a Therapy for Secondary Injury

Traumatic brain injury (TBI) is a leading cause of mortality, sensorimotor morbidity, and neurocognitive disability. Neuroinflammation is one of the key drivers causing secondary brain injury after TBI. Therefore, attenuation of the inflammatory response is a potential therapeutic goal. This review summarizes the most important neuroinflammatory pathophysiology resulting from TBI and the clinical trials performed to attenuate neuroinflammation. Studies show that non-selective attenuation of the inflammatory response, in the early phase after TBI, might be detrimental and that there is a gap in the literature regarding pharmacological trials targeting specific pathways. The complement system and its crosstalk with the coagulation system play an important role in the pathophysiology of secondary brain injury after TBI. Therefore, regaining control over the complement cascades by inhibiting overshooting activation might constitute useful therapy. Activation of the complement cascade is an early component of neuroinflammation, making it a potential target to mitigate neuroinflammation in TBI. Therefore, we have described pathophysiological aspects of complement inhibition and summarized animal studies targeting the complement system in TBI. We also present the first clinical trial aimed at inhibition of complement activation in the early days after brain injury to reduce the risk of morbidity and mortality following severe TBI.

Prediction of Intracranial Hypertension and Brain Tissue Hypoxia Utilizing High-Resolution Data from the BOOST-II Clinical Trial

The current approach to intracranial hypertension and brain tissue hypoxia is reactive, based on fixed thresholds. We used statistical machine learning on high-frequency intracranial pressure (ICP) and partial brain tissue oxygen tension (PbtO₂) data obtained from the BOOST-II trial with the goal of constructing robust quantitative models to predict ICP/PbtO₂ crises. We derived the following machine learning models: logistic regression (LR), elastic net, and random forest. We split the data set into 70–30% for training and testing and utilized a discrete-time survival analysis framework and 5-fold hyperparameter optimization strategy for all models. We compared model performances on discrimination between events and non-events of increased ICP or low PbtO₂ with the area under the receiver operating characteristic (AUROC) curve. We further analyzed clinical utility through a decision curve analysis (DCA). When considering discrimination, the number of features, and interpretability, we identified the RF model that combined the most recent ICP reading, episode number, and longitudinal trends over the preceding 30 min as the best performing for predicting ICP crisis events within the next 30 min (AUC 0.78). For PbtO₂, the LR model utilizing the most recent reading, episode number, and longitudinal trends over the preceding 30 min was the best performing (AUC, 0.84). The DCA showed clinical usefulness for wide risk of thresholds for both ICP and PbtO₂ predictions. Acceptable alerting thresholds could range from 20% to 80% depending on a patient-specific assessment of the benefit-risk ratio of a given intervention in response to the alert.

PHLPP Inhibitor NSC74429 Is Neuroprotective in Rodent Models of Cardiac Arrest and Traumatic Brain Injury

Pleckstrin homology domain and leucine rich repeat protein phosphatase (PHLPP) knockout mice have improved outcomes after a stroke, traumatic brain injury (TBI), and decreased maladaptive vascular remodeling following vascular injury. Thus, small-molecule PHLPP inhibitors have the potential to improve neurological outcomes in a variety of conditions. There is a paucity of data on the efficacy of the known experimental PHLPP inhibitors, and not all may be suited for targeting acute brain injury. Here, we assessed several PHLPP inhibitors not previously explored for neuroprotection (NSC13378, NSC25247, and NSC74429) that had favorable predicted chemistries for targeting the central nervous system (CNS). Neuronal culture studies in staurosporine (apoptosis), glutamate (excitotoxicity), and hydrogen peroxide (necrosis/oxidative stress) revealed that NSC74429 at micromolar concentrations was the most neuroprotective. Subsequent testing in a rat model of asphyxial cardiac arrest, and in a mouse model of severe TBI, showed that serial dosing of 1 mg/kg of NSC74429 over 3 days improved hippocampal survival in both models. Taken together, NSC74429 is neuroprotective across multiple insult mechanisms. Future pharmacokinetic and pharmacodynamic (PK/PD) studies are warranted to optimize dosing, and mechanistic studies are needed to determine the percentage of neuroprotection mediated by PHLPP1/2 inhibition, or potentially from the modulation of PHLPP-independent targets.

Determinants of Adherence to Best Practice in Severe Traumatic Brain Injury: A Qualitative Study

Background

Management of patients with severe traumatic brain injury (sTBI) is highly variable and inconsistently aligned with evidence derived from high-quality trials, including those examining intravenous fluid resuscitation and use of decompressive craniectomy surgery. This study explored the barriers and facilitators of general and specific evidence-based practices in sTBI from the perspectives of stakeholder clinicians.

Methods

This was a qualitative study of semistructured interviews conducted with specialist clinicians responsible for acute care of patients with sTBI. Interview analysis was guided by the Theoretical domains framework (TDF), and key themes were mapped to relevant TDF behavioral domains.

Results

Ten neurosurgeons, 12 intensive care specialists, and three trauma physicians from six high-income countries participated between May 2020 and May 2021. Key TDF domains were environmental context and resources, social influences, and beliefs about consequences. Evidence-aligned management of patients with sTBI is perceived to be facilitated by admission to academic research-oriented hospitals, development of local practice protocols, and interdisciplinary collaboration. Determinants of specific practices varied and included health policy change for fluid resuscitation and development of patient-centered goals for surgical decision-making.

Conclusions

In choosing interventions for patients with sTBI, clinicians integrate local environmental, social, professional, and emotional influences with evidence and associated clinical practice guideline recommendations. This study highlights determinants of evidence-based practice that may inform implementation efforts and thereby improve outcomes for patients with sTBI.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12028-022-01551-x.

Predicting outcome of patients with prolonged disorders of consciousness using machine learning models based on medical complexity

Patients with severe acquired brain injury and prolonged disorders of consciousness (pDoC) are characterized by high clinical complexity and high risk to develop medical complications. The present multi-center longitudinal study aimed at investigating the impact of medical complications on the prediction of clinical outcome by means of machine learning models. Patients with pDoC were consecutively enrolled at admission in 23 intensive neurorehabilitation units (IRU) and followed-up at 6 months from onset via the Glasgow Outcome Scale-Extended (GOSE). Demographic and clinical data at study entry and medical complications developed within 3 months from admission were collected. Machine learning models were developed, targeting neurological outcomes at 6 months from brain injury using data collected at admission. Then, after concatenating predictions of such models to the medical complications collected within 3 months, a cascade model was developed. One hundred seventy six patients with pDoC (M: 123, median age 60.2 years) were included in the analysis. At admission, the best performing solution (k-Nearest Neighbors regression, KNN) resulted in a median validation error of 0.59 points [IQR 0.14] and a classification accuracy of dichotomized GOS-E of 88.6%. Coherently, at 3 months, the best model resulted in a median validation error of 0.49 points [IQR 0.11] and a classification accuracy of 92.6%. Interpreting the admission KNN showed how the negative effect of older age is strengthened when patients' communication levels are high and ameliorated when no communication is present. The model trained at 3 months showed appropriate adaptation of the admission prediction according to the severity of the developed medical complexity in the first 3 months. In this work, we developed and cross-validated an interpretable decision support tool capable of distinguishing patients which will reach sufficient independence levels at 6 months (GOS-E > 4). Furthermore, we provide an updated prediction at 3 months, keeping in consideration the rehabilitative path and the risen medical complexity.

Clustering identifies endotypes of traumatic brain injury in an intensive care cohort: a CENTER-TBI study

BACKGROUND

While the Glasgow coma scale (GCS) is one of the strongest outcome predictors, the current classification of traumatic brain injury (TBI) as 'mild', 'moderate' or 'severe' based on this fails to capture enormous heterogeneity in pathophysiology and treatment response. We hypothesized that data-driven characterization of TBI could identify distinct endotypes and give mechanistic insights.

METHODS

We developed an unsupervised statistical clustering model based on a mixture of probabilistic graphs for presentation (< 24 h) demographic, clinical, physiological, laboratory and imaging data to identify subgroups of TBI patients admitted to the intensive care unit in the CENTER-TBI dataset (N = 1,728). A cluster similarity index was used for robust determination of optimal cluster number. Mutual information was used to quantify feature importance and for cluster interpretation.

RESULTS

Six stable endotypes were identified with distinct GCS and composite systemic metabolic stress profiles, distinguished by GCS, blood lactate, oxygen saturation, serum creatinine, glucose, base excess, pH, arterial partial pressure of carbon dioxide, and body temperature. Notably, a cluster with 'moderate' TBI (by traditional classification) and deranged metabolic profile, had a worse outcome than a cluster with 'severe' GCS and a normal metabolic profile. Addition of cluster labels significantly improved the prognostic precision of the IMPACT (International Mission for Prognosis and Analysis of Clinical trials in TBI) extended model, for prediction of both unfavourable outcome and mortality (both p < 0.001).

CONCLUSIONS

Six stable and clinically distinct TBI endotypes were identified by probabilistic unsupervised clustering. In addition to presenting neurology, a profile of biochemical derangement was found to be an important distinguishing feature that was both biologically plausible and associated with outcome. Our work motivates refining current TBI classifications with factors describing metabolic stress. Such data-driven clusters suggest TBI endotypes that merit investigation to identify bespoke treatment strategies to improve care. Trial registration The core study was registered with ClinicalTrials.gov, number NCT02210221 , registered on August 06, 2014, with Resource Identification Portal (RRID: SCR_015582).

Brain Shock—Toward Pathophysiologic Phenotyping in Traumatic Brain Injury

Severe traumatic brain injury (TBI) is a heterogeneous pathophysiologic entity where multiple interacting mechanisms are operating. This viewpoint offers an emerging, clinically actionable understanding of the pathophysiologic heterogeneity and phenotypic diversity that comprise secondary brain injury based on multimodality neuromonitoring data. This pathophysiologic specification has direct implications for diagnostic, monitoring, and therapeutic planning. Cerebral shock can be helpfully subanalyzed into categories via an examination of the different types of brain tissue hypoxia and substrate failure: a) ischemic or flow dependent; b) flow-independent, which includes oxygen diffusion limitation, mitochondrial failure, and arteriovenous shunt; c) low extraction; and d) hypermetabolic. This approach could lead to an alternative treatment paradigm toward optimizing cerebral oxidative metabolism and energy crisis avoidance. Our bedside approach to TBI should respect the pathophysiologic diversity involved; operationalizing it in types of “brain shock” can be one such approach.

Challenges Encountered in Surgical Traumatic Brain Injury Research: A Need for Methodological Improvement of Future Studies

BACKGROUND

Investigating neurosurgical interventions for traumatic brain injury (TBI) involves complex methodological and practical challenges. In the present report, we have provided an overview of the current state of neurosurgical TBI research and discussed the key challenges and possible solutions.

METHODS

The content of our report was based on an extensive literature review and personal knowledge and expert opinions of senior neurosurgeon researchers and epidemiologists.

RESULTS

Current best practice research strategies include randomized controlled trials (RCTs) and comparative effectiveness research. The performance of RCTs has been complicated by the heterogeneity of TBI patient populations with the associated sample size requirements, the traditional eminence-based neurosurgical culture, inadequate research budgets, and the often acutely life-threatening setting of severe TBI. Statistical corrections can mitigate the effects of heterogeneity, and increasing awareness of clinical equipoise and informed consent alternatives can improve trial efficiency. The substantial confounding by indication, which limits the interpretability of observational research, can be circumvented by using an instrumental variable analysis. Traditional TBI outcome measures remain relevant but do not adequately capture the subtleties of well-being, suggesting a need for multidimensional approaches to outcome assessments.

CONCLUSIONS

In settings in which traditional RCTs are difficult to conduct and substantial confounding by indication can be present, observational studies using an instrumental variable analysis and "pragmatic" RCTs are promising alternatives. Embedding TBI research into standard clinical practice should be more frequently considered but will require fundamental modifications to the current health care system. Finally, multimodality outcome assessment will be key to improving future surgical and nonsurgical TBI research.

Traumatic Brain Injury: What Is a Favorable Outcome?

Traumatic brain injury (TBI) results in disparate outcomes ranging from persistent disorders of consciousness to symptom resolution. Despite the breadth and complexity of TBI recovery, most clinical trials dichotomize outcome by establishing an arbitrary cut-point, above and below which recovery is described as "favorable" and "unfavorable," respectively. For example, the widely used eight-level Glasgow Outcome Scale-Extended (GOSE) is typically collapsed into these two categories. Dichotomizing the GOSE into "favorable" and "unfavorable" outcome may limit detection of treatment effects in TBI clinical trials, contribute to imprecise prognostic counseling, and unduly influence decision-making with regard to withdrawal of life-sustaining therapy. We illustrate the lack of standardization in defining "unfavorable" and "favorable" TBI outcome on the GOSE by identifying the broad range of cut-points, from a score of 3 (part-time supervision in the home required) to 7 (presence of some residual of symptoms), that have been used to dichotomize the GOSE. We also highlight the ethical concerns related to characterizing TBI outcomes solely from the perspective of investigators and clinicians, rather than patients and caregivers. Finally, we suggest that a pragmatic, immediate solution to GOSE dichotomization is to report the likelihood of achieving each of the eight GOSE outcome levels and propose a study design for a new patient- and caregiver-centered TBI outcome metric.

Biofidelic dynamic compression of human cortical spheroids reproduces neurotrauma phenotypes

Fundamental questions about patient heterogeneity and human-specific pathophysiology currently obstruct progress towards a therapy for traumatic brain injury (TBI). Human in vitro models have the potential to address these questions. 3D spheroidal cell culture protocols for human-origin neural cells have several important advantages over their 2D monolayer counterparts. Three dimensional spheroidal cultures may mature more quickly, develop more biofidelic electrophysiological activity and/or reproduce some aspects of brain architecture. Here, we present the first human in vitro model of non-penetrating TBI employing 3D spheroidal cultures. We used a custom-built device to traumatize these spheroids in a quantifiable, repeatable and biofidelic manner and correlated the heterogeneous, mechanical strain field with the injury phenotype. Trauma reduced cell viability, mitochondrial membrane potential and spontaneous, synchronous, electrophysiological activity in the spheroids. Electrophysiological deficits emerged at lower injury severities than changes in cell viability. Also, traumatized spheroids secreted lactate dehydrogenase, a marker of cell damage, and neurofilament light chain, a promising clinical biomarker of neurotrauma. These results demonstrate that 3D human in vitro models can reproduce important phenotypes of neurotrauma in vitro.

Determining minimally clinically important differences for outcome measures in patients with chronic motor deficits secondary to traumatic brain injury

OBJECTIVE

To determine minimally clinically important differences (MCIDs) for Disability Rating Scale (DRS), Fugl-Meyer Upper Extremity Subscale (FM-UE), Fugl-Meyer Lower Extremity Subscale (FM-LE), and Fugl-Meyer Motor Scale (FMMS) in patients with chronic motor deficits secondary to traumatic brain injury (TBI).

METHODS

Retrospective analysis from the 1-year, double-blind, randomized, surgical sham-controlled, Phase 2 STEMTRA trial (NCT02416492), in which patients with chronic motor deficits secondary to TBI (N = 61) underwent intracerebral stereotactic implantation of modified bone marrow-derived mesenchymal stromal (SB623) cells. MCIDs for DRS, FM-UE, FM-LE, and FMMS were triangulated with distribution-based, anchor-based, and Delphi panel estimates.

RESULTS

Triangulated MCIDs were: 1) -1.5 points for the Disability Rating Scale; 2) 6.2 points for the Fugl-Meyer Upper Extremity Subscale; 3) 3.2 points for the Fugl-Meyer Lower Extremity Subscale; and 4) 8.4 points for the Fugl-Meyer Motor Scale.

CONCLUSIONS

For the first time in the setting of patients with chronic motor deficits secondary to TBI, this study reports triangulated MCIDs for: 1) DRS, a measure of global outcome; and 2) Fugl-Meyer Scales, measures of motor impairment. These findings guide the use of DRS and Fugl-Meyer Scales in the assessment of global disability outcome and motor impairment in future TBI clinical trials.

Roadmap for Advancing Pre-Clinical Science in Traumatic Brain Injury

Pre-clinical models of disease have long played important roles in the advancement of new treatments. However, in traumatic brain injury (TBI), despite the availability of numerous model systems, translation from bench to bedside remains elusive. Integrating clinical relevance into pre-clinical model development is a critical step toward advancing therapies for TBI patients across the spectrum of injury severity. Pre-clinical models include in vivo and ex vivo animal work-both small and large-and in vitro modeling. The wide range of pre-clinical models reflect substantial attempts to replicate multiple aspects of TBI sequelae in humans. Although these models reveal multiple putative mechanisms underlying TBI pathophysiology, failures to translate these findings into successful clinical trials call into question the clinical relevance and applicability of the models. Here, we address the promises and pitfalls of pre-clinical models with the goal of evolving frameworks that will advance translational TBI research across models, injury types, and the heterogenous etiology of pathology.

Omega-3 Fatty Acids and Vitamin D Decrease Plasma T-Tau, GFAP, and UCH-L1 in Experimental Traumatic Brain Injury

Traumatic brain injury (TBI) results in neuronal, axonal and glial damage. Interventions targeting neuroinflammation to enhance recovery from TBI are needed. Exercise is known to improve cognitive function in TBI patients. Omega-3 fatty acids and vitamin D reportedly reduce inflammation, and in combination, might improve TBI outcomes. This study examined how an anti-inflammatory diet affected plasma TBI biomarkers, voluntary exercise and behaviors following exposure to mild TBI (mTBI). Adult, male rats were individually housed in cages fitted with running wheels and daily running distance was recorded throughout the study. A modified weight drop method induced mTBI, and during 30 days post-injury, rats were fed diets supplemented with omega-3 fatty acids and vitamin D₃ (AIDM diet), or non-supplemented AIN-76A diets (CON diet). Behavioral tests were periodically conducted to assess functional deficits. Plasma levels of Total tau (T-tau), glial fibrillary acidic protein (GFAP), ubiquitin c-terminal hydrolase L1 (UCH-L1) and neurofilament light chain (NF-L) were measured at 48 h, 14 days, and 30 days post-injury. Fatty acid composition of food, plasma, and brain tissues was determined. In rats exposed to mTBI, NF-L levels were significantly elevated at 48 h post-injury (P < 0.005), and decreased to levels seen in uninjured rats by 14 days post-injury. T-tau, GFAP, and UCH-L1 plasma levels did not change at 48 h or 14 days post-injury. However, at 30 days post-injury, T-tau, GFAP and UCH-L1 all significantly increased in rats exposed to mTBI and fed CON diets (P < 0.005), but not in rats fed AIDM diets. Behavioral tests conducted post-injury showed that exercise counteracted cognitive deficits associated with mTBI. The AIDM diets significantly increased docosahexaenoic acid levels in plasma and brain tissue (P < 0.05), and in serum levels of vitamin D (P < 0.05). The temporal response of the four injury biomarkers examined is consistent with studies by others demonstrating acute and chronic neural tissue damage following exposure to TBI. The anti-inflammatory diet significantly altered the temporal profiles of plasma T-tau, GFAP, and UCH-L1 following mTBI. Voluntary exercise protected against mTBI-induced cognitive deficits, but had no impact on plasma levels of neurotrauma biomarkers. Thus, the prophylactic effect of exercise, when combined with an anti-inflammatory diet, may facilitate recovery in patients with mTBI.

Dexamethasone for the treatment of traumatic brain injured patients with brain contusions and pericontusional edema: Study protocol for a prospective, randomized and double blind trial

BACKGROUND

Traumatic brain injury (TBI) constitutes a leading cause of death and disability. Patients with TBI and cerebral contusions developing pericontusional edema are occasionally given dexamethasone on the belief that this edema is similar to that of tumors, in which the beneficial effect of dexamethasone has been demonstrated.

METHODS

The DEXCON TBI trial is a multicenter, pragmatic, randomized, triple-blind, placebo controlled trial to quantify the effects of dexamethasone on the prognosis of TBI patients with brain contusions and pericontusional edema. Adult patients who fulfill the elegibility criteria will be randomized to dexamethasone/placebo in a short and descending course: 4 mg/6 h (2 days); 4 mg/8 hours (2 days); 2 mg/6 hours (2 days); 2 mg/8 hours (2 days); 1 mg/8 hours (2 days); 1 mg/12 hours (2 days). The primary outcome is the Glasgow Scale Outcome Extended (GOSE) performed 1 month and 6 months after TBI. Secondary outcomes are: number of episodes of neurological deterioration; symptoms associated with TBI; adverse events; volume of pericontusional edema before and after 12 days of treatment; results of the neuropsychological tests one month and 6 months after TBI. The main analysis will be on an "intention-to-treat" basis. Logistic regression will estimate the effect of dexamethasone/placebo on GOSE at one month and at 6 months, dichotomized in unfavorable outcome (GOSE 1-6) and favorable outcome (GOSE 7-8). Efficacy will also be analyzed using the 'sliding dichotomy'. An interim and safety analysis will be performed including patients recruited during the first year to calculate the conditional power. A study with 600 patients would have 80% power (2 sided alpha = 5%) to detect a 12% absolute increase (from 50% to 62%) in good recovery.

DISCUSSION

This is a confirmative trial to elucidate the therapeutic efficacy of dexamethasone in a very specific group of TBI patients: patients with brain contusions and pericontusional edema. This trial could become an important milestone for TBI patients as nowadays there is no effective treatment in this type of patients.

TRIAL REGISTRATION

eudraCT: 2019-004038-41; Clinical Trials.gov: NCT04303065.

The genetic basis of inter-individual variation in recovery from traumatic brain injury

Traumatic brain injury (TBI) is one of the leading causes of death among young people, and is increasingly prevalent in the aging population. Survivors of TBI face a spectrum of outcomes from short-term non-incapacitating injuries to long-lasting serious and deteriorating sequelae. TBI is a highly complex condition to treat; many variables can account for the observed heterogeneity in patient outcome. The limited success of neuroprotection strategies in the clinic has led to a new emphasis on neurorestorative approaches. In TBI, it is well recognized clinically that patients with similar lesions, age, and health status often display differences in recovery of function after injury. Despite this heterogeneity of outcomes in TBI, restorative treatment has remained generic. There is now a new emphasis on developing a personalized medicine approach in TBI, and this will require an improved understanding of how genetics impacts on long-term outcomes. Studies in animal model systems indicate clearly that the genetic background plays a role in determining the extent of recovery following an insult. A candidate gene approach in human studies has led to the identification of factors that can influence recovery. Here we review studies of the genetic basis for individual differences in functional recovery in the CNS in animals and man. The application of in vitro modeling with human cells and organoid cultures, along with whole-organism studies, will help to identify genes and networks that account for individual variation in recovery from brain injury, and will point the way towards the development of new therapeutic approaches.

The Rise of Inflow Cisternostomy in Resource-Limited Settings: Rationale, Limitations, and Future Challenges

Low- and middle-income countries (LMICs) bear most of the global burden of traumatic brain injury (TBI), but they lack the resources to address this public health crisis. For TBI guidelines and innovations to be effective, they must consider the context in LMICs; keeping this in mind, this article will focus on the history, pathophysiology, practice, evidence, and implications of cisternostomy. In this narrative review, the author discusses the history, pathophysiology, practice, evidence, and implications of cisternostomy. Cisternostomy for the management of TBI is an innovation developed in LMICs, primarily for LMICs. Its practice is based on the cerebrospinal fluid shift edema theory that attributes injury to increased pressure within the subarachnoid space due to subarachnoid hemorrhage and subsequent dysfunction of glymphatic drainage. Early reports of the technique report significant improvements in the Glasgow Outcome Scale, lower mortality rates, and shorter intensive care unit durations. Most reports are single-center studies with small sample sizes, and the technique requires experience and skill. These limitations have led to criticisms and slow adoption of the technique. Further research is needed to establish the effect of cisternostomy on TBI outcomes.

"Omics" in traumatic brain injury: novel approaches to a complex disease

BACKGROUND

To date, there is neither any pharmacological treatment with efficacy in traumatic brain injury (TBI) nor any method to halt the disease progress. This is due to an incomplete understanding of the vast complexity of the biological cascades and failure to appreciate the diversity of secondary injury mechanisms in TBI. In recent years, techniques for high-throughput characterization and quantification of biological molecules that include genomics, proteomics, and metabolomics have evolved and referred to as omics.

METHODS

In this narrative review, we highlight how omics technology can be applied to potentiate diagnostics and prognostication as well as to advance our understanding of injury mechanisms in TBI.

RESULTS

The omics platforms provide possibilities to study function, dynamics, and alterations of molecular pathways of normal and TBI disease states. Through advanced bioinformatics, large datasets of molecular information from small biological samples can be analyzed in detail and provide valuable knowledge of pathophysiological mechanisms, to include in prognostic modeling when connected to clinically relevant data. In such a complex disease as TBI, omics enables broad categories of studies from gene compositions associated with susceptibility to secondary injury or poor outcome, to potential alterations in metabolites following TBI.

CONCLUSION

The field of omics in TBI research is rapidly evolving. The recent data and novel methods reviewed herein may form the basis for improved precision medicine approaches, development of pharmacological approaches, and individualization of therapeutic efforts by implementing mathematical "big data" predictive modeling in the near future.

Low-Value Clinical Practices in Adult Traumatic Brain Injury: An Umbrella Review

Despite numerous interventions and treatment options, the outcomes of traumatic brain injury (TBI) have improved little over the last 3 decades, which raises concern about the value of care in this patient population. We aimed to synthesize the evidence on 14 potentially low-value clinical practices in TBI care. Using umbrella review methodology, we identified systematic reviews evaluating the effectiveness of 14 potentially low-value practices in adults with acute TBI. We present data on methodological quality (Assessing the Methodological Quality of Systematic Reviews), reported effect sizes, and credibility of evidence (I to IV). The only clinical practice with evidence of benefit was therapeutic hypothermia (credibility of evidence II to IV). However, the most recent meta-analysis on hypothermia based on high-quality trials suggested harm (credibility of evidence IV). Meta-analyses on platelet transfusion for patients on antiplatelet therapy were all consistent with harm but were statistically non-significant. For the following practices, effect estimates were consistently close to the null: computed tomography (CT) in adults with mild TBI who are low-risk on a validated clinical decision rule; repeat CT in adults with mild TBI on anticoagulant therapy with no clinical deterioration; antibiotic prophylaxis for external ventricular drain placement; and decompressive craniectomy for refractory intracranial hypertension. We identified five clinical practices with evidence of lack of benefit or harm. However, evidence could not be considered to be strong for any clinical practice as effect measures were imprecise and heterogeneous, systematic reviews were often of low quality, and most included studies had a high risk of bias.

An evidence-based methodology for systematic evaluation of clinical outcome assessment measures for traumatic brain injury

INTRODUCTION

The high failure rate of clinical trials in traumatic brain injury (TBI) may be attributable, in part, to the use of untested or insensitive measurement instruments. Of more than 1,000 clinical outcome assessment measures (COAs) for TBI, few have been systematically vetted to determine their performance within specific "contexts of use (COU)." As described in guidance issued by the U.S. Food and Drug Administration (FDA), the COU specifies the population of interest and the purpose for which the COA will be employed. COAs are commonly used for screening, diagnostic categorization, outcome prediction, and establishing treatment effectiveness. COA selection typically relies on expert consensus; there is no established methodology to match the appropriateness of a particular COA to a specific COU. We developed and pilot-tested the Evidence-Based Clinical Outcome assessment Platform (EB-COP) to systematically and transparently evaluate the suitability of TBI COAs for specific purposes.

METHODS AND FINDINGS

Following a review of existing literature and published guidelines on psychometric standards for COAs, we developed a 6-step, semi-automated, evidence-based assessment platform to grade COA performance for six specific purposes: diagnosis, symptom detection, prognosis, natural history, subgroup stratification and treatment effectiveness. Mandatory quality indicators (QIs) were identified for each purpose using a modified Delphi consensus-building process. The EB-COP framework was incorporated into a Qualtrics software platform and pilot-tested on the Glasgow Outcome Scale-Extended (GOSE), the most widely-used COA in TBI clinical studies.

CONCLUSION

The EB-COP provides a systematic methodology for conducting more precise, evidence-based assessment of COAs by evaluating performance within specific COUs. The EB-COP platform was shown to be feasible when applied to a TBI COA frequently used to detect treatment effects and can be modified to address other populations and COUs. Additional testing and validation of the EB-COP are warranted.

Management of Australian Patients with Severe Traumatic Brain Injury: Are Potentially Harmful Treatments Still Used?

Clinical trials have shown that intravenous albumin and decompressive craniectomy to treat early refractory intracranial hypertension can cause harm in patients with severe traumatic brain injury (TBI). The extent to which these treatments remain in use is unknown. We conducted a multi-center retrospective cohort study of adult patients with severe TBI admitted to five neurotrauma centers across Australia between April 2013 and March 2015. Patients were identified from local trauma and intensive care unit (ICU) registries and followed until hospital discharge. Main outcome measures were the administration of intravenous albumin, and decompressive craniectomy for intracranial hypertension. Analyses were predominantly descriptive. There were 303 patients with severe TBI, of whom a minority received albumin (6.9%) or underwent early decompressive craniectomy for treatment of refractory intracranial hypertension complicating diffuse TBI (2.3%). The median (intequartile range [IQR]) age was 35 (24, 58), and most injuries were caused by road traffic accidents (57.4%) or falls (25.1%). Overall, 34.3% of patients died while in the hospital and the remainder were discharged to rehabilitation (44.6%), other health care facilities (4.6%), or home (16.5%). There were no patient characteristics significantly associated with use of albumin or craniectomy. Intravenous albumin and craniectomy for treatment of intracranial hypertension were used infrequently in Australian neurotrauma centers, indicating alignment between best available evidence and practice.

The ethical and legal status of neurosurgical guidelines: the neurosurgeon's golden fleece or Achilles' heel?

Neurosurgical guidelines are fundamental for evidence-based practice and have considerably increased both in number and content over the last decades. Yet, guidelines in neurosurgery are not without limitations, as they are overwhelmingly based on low-level evidence. Such recommendations have in the past been occasionally overturned by well-designed randomized controlled trials (RCTs), demonstrating the volatility of poorly underpinned evidence. Furthermore, even RCTs in surgery come with several limitations; most notably, interventions are often insufficiently standardized and assume a homogeneous patient population, which is not always applicable to neurosurgery. Lastly, guidelines are often outdated by the time they are published and smaller fields such as neurosurgery may lack a sufficient workforce to provide regular updates. These limitations raise the question of whether it is ethical to use low-level evidence for guideline recommendations, and if so, how strictly guidelines should be adhered to from an ethical and legal perspective. This article aims to offer a critical approach to the ethical and legal status of guidelines in neurosurgery. To this aim, the authors discuss: 1) the current state of neurosurgical guidelines and the evidence they are based on; 2) the degree of implementation of these guidelines; 3) the legal status of guidelines in medical disciplinary cases; and 4) the ethical balance between confident and critical use of guidelines. Ultimately, guidelines are neither laws that should always be followed nor purely academic efforts with little practical use. Every patient is unique, and tailored treatment defined by the surgeon will ensure optimal care; guidelines play an important role in creating a solid base that can be adhered to or deviated from, depending on the situation. From a research perspective, it is inevitable to rely on weaker evidence initially in order to generate more robust evidence later, and clinician-researchers have an ethical duty to contribute to generating and improving neurosurgical guidelines.

Drug Repurposing in Neurological Disorders: Implications for Neurotherapy in Traumatic Brain Injury

Traumatic brain injury (TBI) remains a significant leading cause of death and disability among adults and children globally. To date, there are no Food and Drug Administration-approved drugs that can substantially attenuate the sequelae of TBI. The innumerable challenges faced by the conventional de novo discovery of new pharmacological agents led to the emergence of alternative paradigm, which is drug repurposing. Repurposing of existing drugs with well-characterized mechanisms of action and human safety profiles is believed to be a promising strategy for novel drug use. Compared to the conventional discovery pathways, drug repurposing is less costly, relatively rapid, and poses minimal risk of the adverse outcomes to study on participants. In recent years, drug repurposing has covered a wide range of neurodegenerative diseases and neurological disorders including brain injury. This review highlights the advances in drug repurposing and presents some of the promising candidate drugs for potential TBI treatment along with their possible mechanisms of neuroprotection. Edaravone, glyburide, ceftriaxone, levetiracetam, and progesterone have been selected due to their potential role as putative TBI neurotherapeutic agents. These drugs are Food and Drug Administration-approved for purposes other than brain injuries; however, preclinical and clinical studies have shown their efficacy in ameliorating the various detrimental outcomes of TBI.

Efficacy of acute administration of inhaled argon on traumatic brain injury in mice

BACKGROUND

Whilst there has been progress in supportive treatment for traumatic brain injury (TBI), specific neuroprotective interventions are lacking. Models of ischaemic heart and brain injury show the therapeutic potential of argon gas, but it is still not known whether inhaled argon (iAr) is protective in TBI. We tested the effects of acute administration of iAr on brain oedema, tissue micro-environmental changes, neurological functions, and structural outcome in a mouse model of TBI.

METHODS

Anaesthetised adult C57BL/6J mice were subjected to severe TBI by controlled cortical impact. Ten minutes after TBI, the mice were randomised to 24 h treatments with iAr 70%/O₂ 30% or air (iCtr). Sensorimotor deficits were evaluated up to 6 weeks post-TBI by three independent tests. Cognitive function was evaluated by Barnes maze test at 4 weeks. MRI was done to examine brain oedema at 3 days and white matter damage at 5 weeks. Microglia/macrophages activation and functional commitment were evaluated at 1 week after TBI by immunohistochemistry.

RESULTS

iAr significantly accelerated sensorimotor recovery and improved cognitive deficits 1 month after TBI, with less white matter damage in the ipsilateral fimbria and body of the corpus callosum. Early changes underpinning protection included a reduction of pericontusional vasogenic oedema and of the inflammatory response. iAr significantly reduced microglial activation with increases in ramified cells and the M2-like marker YM1.

CONCLUSIONS

iAr accelerates recovery of sensorimotor function and improves cognitive and structural outcome 1 month after severe TBI in adult mice. Early effects include a reduction of brain oedema and neuroinflammation in the contused tissue.

The weakness of fragility index exposed in an analysis of the traumatic brain injury management guidelines: A meta-epidemiological and simulation study

OBJECTIVES

To perform fragility index (FI) analysis on the evidence that forms the basis of the guidelines for the management of severe traumatic brain injury (TBI), and develop a deeper understanding of the pitfalls associated with FI.

DESIGN

Meta-epidemiological analysis and numerical simulations.

METHODS

The Brain Trauma Foundation guidelines (4th edition) for management of severe TBI were used to identify relevant randomised controlled trials (RCTs). FI based on Fisher's exact test and relative risk was performed on eligible RCTs. The relationship between FI, event counts and P values was explored by exhaustively considering different combinations of outcomes for studies of total size ranging from 80 to 10000. Sample size calculations were also performed for a range of power, baseline risk and relative risk, to determine the influence of study design on FI.

RESULTS

FI analysis of the severe TBI management guidelines revealed that most studies were associated with a low FI. In the majority of studies, FI was of a similar magnitude to the number lost to follow-up. The simulations revealed that while FI was inversely related to P value, a wide range of FI may be associated with a given P value. FI is also affected by sample size, baseline risk and effect size. Sample size calculations suggest that aside from very high-powered studies, most are likely to yield low FI values in the range typically encountered in the literature.

CONCLUSIONS

Many studies are underpowered and are expected to be associated with a small FI. Furthermore, FI over-simplifies the complex, non-linear relationships between sample size, effect size and P value, which hinder comparisons of FI between studies. FI places undue importance on the "significance" of P values and accordingly should only be used sparingly.

Two latent classes of diagnostic and treatment procedures among traumatic brain injury inpatients

To characterize latent classes of diagnostic and/or treatment procedures among hospitalized U.S. adults, 18-64 years, with primary diagnosis of TBI from 2004-2014 Nationwide Inpatient Samples, latent class analysis (LCA) was applied to 10 procedure groups and differences between latent classes on injury, patient, hospital and healthcare utilization outcome characteristics were modeled using multivariable regression. Using 266,586 eligible records, LCA resulted in two classes of hospitalizations, namely, class I (n = 217,988) (mostly non-surgical) and class II (n = 48,598) (mostly surgical). Whereas orthopedic procedures were equally likely among latent classes, skin-related, physical medicine and rehabilitation procedures as well as behavioral health procedures were more likely among class I, and other types of procedures were more likely among class II. Class II patients were more likely to have moderate-to-severe TBI, to be admitted on weekends, to urban, medium-to-large hospitals in Midwestern, Southern or Western regions, and less likely to be > 30 years, female or non-White. Class II patients were also less likely to be discharged home and necessitated longer hospital stays and greater hospitalization charges. Surgery appears to distinguish two classes of hospitalized patients with TBI with divergent healthcare needs, informing the planning of healthcare services in this target population.

HMGB1-Mediated Neuroinflammatory Responses in Brain Injuries: Potential Mechanisms and Therapeutic Opportunities

Brain injuries are devastating conditions, representing a global cause of mortality and morbidity, with no effective treatment to date. Increased evidence supports the role of neuroinflammation in driving several forms of brain injuries. High mobility group box 1 (HMGB1) protein is a pro-inflammatory-like cytokine with an initiator role in neuroinflammation that has been implicated in Traumatic brain injury (TBI) as well as in early brain injury (EBI) after subarachnoid hemorrhage (SAH). Herein, we discuss the implication of HMGB1-induced neuroinflammatory responses in these brain injuries, mediated through binding to the receptor for advanced glycation end products (RAGE), toll-like receptor4 (TLR4) and other inflammatory mediators. Moreover, we provide evidence on the biomarker potential of HMGB1 and the significance of its nucleocytoplasmic translocation during brain injuries along with the promising neuroprotective effects observed upon HMGB1 inhibition/neutralization in TBI and EBI induced by SAH. Overall, this review addresses the current advances on neuroinflammation driven by HMGB1 in brain injuries indicating a future treatment opportunity that may overcome current therapeutic gaps.

Effect of Early Interdisciplinary Rehabilitation for Trauma Patients: A Systematic Review

Objective

To perform a systematic review to assess the current scientific evidence concerning the effect of EIR for trauma patients with or without an associated traumatic brain injury.

Data Source

We performed a systematic search of several electronic (Ovid MEDLINE, Embase, Cochrane Library Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health, and SveMed+) and 2 clinical trial registers (clinicaltrials.gov and International Clinical Trials Registry Platform). In addition, we handsearched reference lists from relevant studies.

Data Extraction

Two review authors independently identified studies that were eligible for inclusion. The primary outcome measures were functional-related outcomes and return to work. The secondary outcome measures were length of stay in hospital, number of days on respirator, complication rate, physical and mental health measures, quality of life, and socioeconomic costs.

Data Synthesis

Four studies with a total number of 409 subjects, all with traumatic brain–associated injuries, were included in this review. The included trials varied considerably in study design, inclusion and exclusion criteria, and had small numbers of participants. All studies were judged to have at least 1 high risk of bias. We found the quality of evidence, for both our primary and secondary outcomes, low.

Conclusions

No studies that matched our inclusion criteria for EIR for trauma patients without traumatic brain injuries could be found. For traumatic brain injuries, there are a limited number of studies demonstrating that EIR has a positive effect on functional outcomes and socioeconomic costs. This review highlights the need for further research in trauma care regarding early phase interdisciplinary rehabilitation.

Effect of Human Umbilical Cord Perivascular Cell-Conditioned Media in an Adult Zebrafish Model of Traumatic Brain Injury

The pathophysiological events of secondary brain injury contribute to poor outcome after traumatic brain injury (TBI). The neuroprotective effects of mesenchymal cells have been extensively studied and evidence suggests that their effects are mostly mediated through paracrine effects. Human umbilical cord perivascular cells (HUCPVCs) are mesenchymal stem cells with potential therapeutic value in TBI. In this study, we assessed the effect of HUCPVC-conditioned media (CM) in an established adult zebrafish model of TBI induced by pulsed high-intensity focused ultrasound (pHIFU). This model demonstrates similarities to mammalian outcome after TBI. Administration of HUCPVC-CM 1 h postinjury (hpi) resulted in improved outcome after pHIFU-induced TBI. Western blot and immunohistochemistry results demonstrated that the HUCPVC-CM reduced (p < 0.05) reactive astrogliosis at 24 hpi. Moreover, at 24 hpi, the HUCPVC-CM treatment resulted in reduced apoptosis in HUCPVC-CM-treated zebrafish. Behavioral analysis demonstrated improvement in locomotor activity (p < 0.05) and anxiety (p < 0.05) at 6 and 24 hpi following HUCPVC-CM treatment. Overall, HUCPVC-CM treatment improved acute outcome measures in pHIFU-injured zebrafish. Collectively, the data demonstrate a cell-free treatment approach for traumatic brain injuries.

Systemic treatment with human amnion epithelial cells after experimental traumatic brain injury

Systemic administration of human amnion epithelial cells (hAECs) was recently shown to reduce neuropathology and improve functional recovery following ischemic stroke in both mice and marmosets. Given the significant neuropathological overlap between ischemic stroke and traumatic brain injury (TBI), we hypothesized that a similar hAEC treatment regime would also improve TBI outcomes. Male mice (12 weeks old, n ​= ​40) were given a sham injury or moderate severity TBI by controlled cortical impact. At 60 ​min post-injury, mice were given a single tail vein injection of either saline (vehicle) or 1 ​× ​10⁶ hAECs suspended in saline. At 24 ​h post-injury, mice were assessed for locomotion and anxiety using an open field, and sensorimotor ability using a rotarod. At 48 ​h post-injury, brains were collected for analysis of immune cells via flow cytometry, or histological evaluation of lesion volume and hAEC penetration. To assess the impact of TBI and hAECs on lymphoid organs, spleen and thymus weights were determined. Treatment with hAECs did not prevent TBI-induced sensorimotor deficits at 24 ​h post-injury. hAECs were detected in the injured brain parenchyma; however, lesion volume was not altered by hAEC treatment. Robust increases in several leukocyte populations in the ipsilateral hemisphere of TBI mice were found when compared to sham mice at 48 ​h post-injury; however, hAEC treatment did not alter brain immune cell numbers. Both TBI and hAEC treatment were found to increase spleen weight. Taken together, these findings indicate that-unlike in ischemic stroke-treatment with hAEC was unable to prevent immune cell infiltration and sensorimotor deficits in the acute stages following controlled cortical impact in mice. Although further investigations are required, our data suggests that the lack of hAEC-induced neuroprotection in the current study may be explained by the differential splenic contributions to neuropathology between these brain injury models.

Efficacy of Ronopterin (VAS203) in Patients with Moderate and Severe Traumatic Brain Injury (NOSTRA phase III trial): study protocol of a confirmatory, placebo-controlled, randomised, double blind, multi-centre study

BACKGROUND

Traumatic brain injury is a leading cause of death and disability worldwide. The nitric oxide synthase inhibitor Ronopterin was shown to improve clinical outcome by enhancing neuroprotection in a phase IIa trial.

METHODS/DESIGN

The NOSTRA phase III trial (Ronopterin in traumatic brain injury) is a multi-centre, prospective, randomised, double-blinded, placebo-controlled, phase III trial in Europe. It aims at determining whether the administration of Ronopterin compared to placebo improves neurological outcome in patients with moderate or severe traumatic brain injury at 6 months after injury. The trial is designed to recruit patients between 18 and 60 years of age with moderate or severe traumatic brain injury (Glasgow Coma Scale score ≥ 3) and requiring insertion of an intracranial pressure probe. Trial patients will receive a 48-h intravenous infusion of either Ronopterin or placebo starting at the earliest 6 h and at the latest 18 h after injury. The primary outcome will be the extended Glasgow Outcome Score (eGOS) at 6 months. Secondary outcomes will include the Quality of Life Index (QOLIBRI) at 6 months after the injury and the eGOS at 3 months after the injury. Additionally, effects on mortality, intracranial pressure and cerebral perfusion pressure are evaluated.

DISCUSSION

The trial aims to provide evidence on the efficacy and safety of Ronopterin in patients with traumatic brain injury.

TRIAL REGISTRATION

EudraCT, 2013-003368-29. Registered on 9 March 2016. ClinicalTrials.gov, NCT02794168. Registered on 8 June 2016. Protocol version 14.0 from 05 November 2018.

Evaluating differential nanoparticle accumulation and retention kinetics in a mouse model of traumatic brain injury via Ktrans mapping with MRI

Traumatic brain injury (TBI) is a leading cause of injury-related death worldwide, yet there are no approved neuroprotective therapies that improve neurological outcome post-injury. Transient opening of the blood-brain barrier following injury provides an opportunity for passive accumulation of intravenously administered nanoparticles through an enhanced permeation and retention-like effect. However, a thorough understanding of physicochemical properties that promote optimal uptake and retention kinetics in TBI is still needed. In this study, we present a robust method for magnetic resonance imaging of nanoparticle uptake and retention kinetics following intravenous injection in a controlled cortical impact mouse model of TBI. Three contrast-enhancing nanoparticles with different hydrodynamic sizes and relaxivity properties were compared. Accumulation and retention were monitored by modelling the permeability coefficient, K^trans, for each nanoparticle within the reproducible mouse model. Quantification of K^trans for different nanoparticles allowed for non-invasive, multi-time point assessment of both accumulation and retention kinetics in the injured tissue. Using this method, we found that 80 nm poly(lactic-co-glycolic acid) nanoparticles had maximal K^trans in a TBI when injected 3 hours post-injury, showing significantly higher accumulation kinetics than the small molecule, Gd-DTPA. This robust method will enable optimization of administration time and nanoparticle physicochemical properties to achieve maximum delivery.