Predicting outcome in traumatic brain injury: development of a novel computerized tomography classification system (Helsinki computerized tomography score)

Simplifying the use of prognostic information in traumatic brain injury. Part 2: Graphical presentation of probabilities

OBJECTIVE Clinical features such as those included in the Glasgow Coma Scale (GCS) score, pupil reactivity, and patient age, as well as CT findings, have clear established relationships with patient outcomes due to neurotrauma. Nevertheless, predictions made from combining these features in probabilistic models have not found a role in clinical practice. In this study, the authors aimed to develop a method of displaying probabilities graphically that would be simple and easy to use, thus improving the usefulness of prognostic information in neurotrauma. This work builds on a companion paper describing the GCS-Pupils score (GCS-P) as a tool for assessing the clinical severity of neurotrauma. METHODS Information about early GCS score, pupil response, patient age, CT findings, late outcome according to the Glasgow Outcome Scale, and mortality were obtained at the individual adult patient level from the CRASH (Corticosteroid Randomisation After Significant Head Injury; n = 9045) and IMPACT (International Mission for Prognosis and Clinical Trials in TBI; n = 6855) databases. These data were combined into a pooled data set for the main analysis. Logistic regression was first used to model the combined association between the GCS-P and patient age and outcome, following which CT findings were added to the models. The proportion of variability in outcomes "explained" by each model was assessed using Nagelkerke's R². RESULTS The authors observed that patient age and GCS-P have an additive effect on outcome. The probability of mortality 6 months after neurotrauma is greater with increasing age, and for all age groups the probability of death is greater with decreasing GCS-P. Conversely, the probability of favorable recovery becomes lower with increasing age and lessens with decreasing GCS-P. The effect of combining the GCS-P with patient age was substantially more informative than the GCS-P, age, GCS score, or pupil reactivity alone. Two-dimensional charts were produced displaying outcome probabilities, as percentages, for 5-year increments in age between 15 and 85 years, and for GCS-Ps ranging from 1 to 15; it is readily seen that the movement toward combinations at the top right of the charts reflects a decreasing likelihood of mortality and an increasing likelihood of favorable outcome. Analysis of CT findings showed that differences in outcome are very similar between patients with or without a hematoma, absent cisterns, or subarachnoid hemorrhage. Taken in combination, there is a gradation in risk that aligns with increasing numbers of any of these abnormalities. This information provides added value over age and GCS-P alone, supporting a simple extension of the earlier prognostic charts by stratifying the original charts in the following 3 CT groupings: none, only 1, and 2 or more CT abnormalities. CONCLUSIONS The important prognostic features in neurotrauma can be brought together to display graphically their combined effects on risks of death or on prospects for independent recovery. This approach can support decision making and improve communication of risk among health care professionals, patients, and their relatives. These charts will not replace clinical judgment, but they will reduce the risk of influences from biases.

Cranioplasty After Severe Traumatic Brain Injury: Effects of Trauma and Patient Recovery on Cranioplasty Outcome

Background

In patients with severe traumatic brain injury (sTBI) treated with decompressive craniectomy (DC), factors affecting the success of later cranioplasty are poorly known.

Objective

We sought to investigate if injury- and treatment-related factors, and state of recovery could predict the risk of major complications in cranioplasty requiring implant removal, and how these complications affect the outcome.

Methods

A retrospective cohort of 40 patients with DC following sTBI and subsequent cranioplasty was studied. Non-injury-related factors were compared with a reference population of 115 patients with DC due to other conditions.

Results

Outcome assessed 1 day before cranioplasty did not predict major complications leading to implant removal. Successful cranioplasty was associated with better outcome, whereas a major complication attenuates patient recovery: in patients with favorable outcome assessed 1 year after cranioplasty, major complication rate was 7%, while in patients with unfavorable outcome the rate was 42% (p = 0.003). Of patients with traumatic subarachnoid hemorrhage (tSAH) on admission imaging 30% developed a major complication, while none of patients without tSAH had a major complication (p = 0.014). Other imaging findings, age, admission Glasgow Coma Scale, extracranial injuries, length of stay at intensive care unit, cranioplasty materials, and timing of cranioplasty were not associated with major complications.

Conclusion

A successful cranioplasty after sTBI and DC predicts favorable outcome 1 year after cranioplasty, while stage of recovery before cranioplasty does not predict cranioplasty success or failure. tSAH on admission imaging is a major risk factor for a major complication leading to implant removal.

Metabolomics Profiling As a Diagnostic Tool in Severe Traumatic Brain Injury

Traumatic brain injury (TBI) is a complex disease with a multifaceted pathophysiology. Impairment of energy metabolism is a key component of secondary insults. This phenomenon is a consequence of multiple potential mechanisms including diffusion hypoxia, mitochondrial failure, and increased energy needs due to systemic trauma responses, seizures, or spreading depolarization. The degree of disturbance in brain metabolism is affected by treatment interventions and reflected in clinical patient outcome. Hence, monitoring of these secondary events in peripheral blood will provide a window into the pathophysiological course of severe TBI. New methods for assessing perturbation of brain metabolism are needed in order to monitor on-going pathophysiological processes and thus facilitate targeted interventions and predict outcome. Circulating metabolites in peripheral blood may serve as sensitive markers of pathological processes in TBI. The levels of these small molecules in blood are less dependent on the integrity of the blood–brain barrier as compared to protein biomarkers. We have recently characterized a specific metabolic profile in serum that is associated with both initial severity and patient outcome of TBI. We found that two medium-chain fatty acids, octanoic and decanoic acids, as well as several sugar derivatives are significantly associated with the severity of TBI. The top ranking peripheral blood metabolites were also highly correlated with their levels in cerebral microdialyzates. Based on the metabolite profile upon admission, we have been able to develop a model that accurately predicts patient outcome. Moreover, metabolomics profiling improved the performance of the well-established clinical prognostication model. In this review, we discuss metabolomics profiling in patients with severe TBI. We present arguments in support of the need for further development and validation of circulating biomarkers of cerebral metabolism and for their use in assessing patients with severe TBI.

Evaluation of novel computerized tomography scoring systems in human traumatic brain injury: An observational, multicenter study

BACKGROUND

Traumatic brain injury (TBI) is a major contributor to morbidity and mortality. Computerized tomography (CT) scanning of the brain is essential for diagnostic screening of intracranial injuries in need of neurosurgical intervention, but may also provide information concerning patient prognosis and enable baseline risk stratification in clinical trials. Novel CT scoring systems have been developed to improve current prognostic models, including the Stockholm and Helsinki CT scores, but so far have not been extensively validated. The primary aim of this study was to evaluate the Stockholm and Helsinki CT scores for predicting functional outcome, in comparison with the Rotterdam CT score and Marshall CT classification. The secondary aims were to assess which individual components of the CT scores best predict outcome and what additional prognostic value the CT scoring systems contribute to a clinical prognostic model.

METHODS AND FINDINGS

TBI patients requiring neuro-intensive care and not included in the initial creation of the Stockholm and Helsinki CT scoring systems were retrospectively included from prospectively collected data at the Karolinska University Hospital (n = 720 from 1 January 2005 to 31 December 2014) and Helsinki University Hospital (n = 395 from 1 January 2013 to 31 December 2014), totaling 1,115 patients. The Marshall CT classification and the Rotterdam, Stockholm, and Helsinki CT scores were assessed using the admission CT scans. Known outcome predictors at admission were acquired (age, pupil responsiveness, admission Glasgow Coma Scale, glucose level, and hemoglobin level) and used in univariate, and multivariable, regression models to predict long-term functional outcome (dichotomizations of the Glasgow Outcome Scale [GOS]). In total, 478 patients (43%) had an unfavorable outcome (GOS 1-3). In the combined cohort, overall prognostic performance was more accurate for the Stockholm CT score (Nagelkerke's pseudo-R2 range 0.24-0.28) and the Helsinki CT score (0.18-0.22) than for the Rotterdam CT score (0.13-0.15) and Marshall CT classification (0.03-0.05). Moreover, the Stockholm and Helsinki CT scores added the most independent prognostic value in the presence of other known clinical outcome predictors in TBI (6% and 4%, respectively). The aggregate traumatic subarachnoid hemorrhage (tSAH) component of the Stockholm CT score was the strongest predictor of unfavorable outcome. The main limitations were the retrospective nature of the study, missing patient information, and the varying follow-up time between the centers.

CONCLUSIONS

The Stockholm and Helsinki CT scores provide more information on the damage sustained, and give a more accurate outcome prediction, than earlier classification systems. The strong independent predictive value of tSAH may reflect an underrated component of TBI pathophysiology. A change to these newer CT scoring systems may be warranted.

Primary decompressive craniectomy is associated with worse neurological outcome in patients with traumatic brain injury requiring acute surgery

BACKGROUND

The role of decompressive craniectomy in treating raised intracranial pressure (ICP) after traumatic brain injuries (TBI) is controversial. The aim of this study was to assess the differences in prognosis of patients initially treated by decompressive craniectomy, craniotomy, or conservatively.

METHODS

We conducted a single-center retrospective study on adult blunt TBI patients admitted to a neurosurgical intensive care unit during 2009-2012. Patients were divided into three groups based on their initial treatment - decompressive craniectomy, craniotomy, and conservative. Primary outcome was 6-month Glasgow Outcome Scale (GOS) dichotomized to favorable outcome (independent) and unfavorable outcome (dependent). The association between initial treatment and outcome was assessed using a logistic regression model adjusting for case-mix using known predictors of outcome.

RESULTS

Of the 822 included patients, 58 patients were in the craniectomy group, 401 patients in the craniotomy group, and 363 patients in the conservatively treated group. Overall, 6-month unfavorable outcome was 48%. After adjusting for case-mix, patients in the decompressive craniectomy group had a statistical significantly higher risk for poor neurological outcome compared to patients in the conservative group (OR 3.06, 95% CI 1.45-6.42) and craniotomy group (OR 3.61, 95% CI 1.74-7.51).

CONCLUSION

In conclusion, patients requiring primary decompressive craniectomy had a higher risk for poor neurological outcome compared to patients undergoing craniotomy or were conservatively treated. It is plausible that the poor prognosis is related to the TBI severity itself rather than the intervention. Further prospective randomized trials are required to establish the role of decompressive craniectomy in the treatment of patients with TBI.

Volumetric analysis of day of injury computed tomography is associated with rehabilitation outcomes after traumatic brain injury

BACKGROUND

Day-of-injury (DOI) brain lesion volumes in traumatic brain injury (TBI) patients are rarely used to predict long-term outcomes in the acute setting. The purpose of this study was to investigate the relationship between acute brain injury lesion volume and rehabilitation outcomes in patients with TBI at a level one trauma center.

METHODS

Patients with TBI who were admitted to our rehabilitation unit after the acute care trauma service from February 2009-July 2011 were eligible for the study. Demographic data and outcome variables including cognitive and motor Functional Independence Measure (FIM) scores, length of stay (LOS) in the rehabilitation unit, and ability to return to home were obtained. The DOI quantitative injury lesion volumes and degree of midline shift were obtained from DOI brain computed tomography scans. A multiple stepwise regression model including 13 independent variables was created. This model was used to predict postrehabilitation outcomes, including FIM scores and ability to return to home. A p value less than 0.05 was considered significant.

RESULTS

Ninety-six patients were enrolled in the study. Mean age was 43 ± 21 years, admission Glasgow Coma Score was 8.4 ± 4.8, Injury Severity Score was 24.7 ± 9.9, and head Abbreviated Injury Scale score was 3.73 ± 0.97. Acute hospital LOS was 12.3 ± 8.9 days, and rehabilitation LOS was 15.9 ± 9.3 days. Day-of-injury TBI lesion volumes were inversely associated with cognitive FIM scores at rehabilitation admission (p = 0.004) and discharge (p = 0.004) and inversely associated with ability to be discharged to home after rehabilitation (p = 0.006).

CONCLUSION

In a cohort of patients with moderate to severe TBI requiring a rehabilitation unit stay after the acute care hospital stay, DOI brain injury lesion volumes are associated with worse cognitive FIM scores at the time of rehabilitation admission and discharge. Smaller-injury volumes were associated with eventual discharge to home. Volumetric neuroimaging in the acute injury phase may improve surgeons' ultimate outcome predictions in TBI patients.

LEVEL OF EVIDENCE

Prognostic/epidemiologic study, level V.

Formulation of a Three-Tier Cisternal Grade as a Predictor of In-Hospital Outcome from a Prospective Study of Patients with Traumatic Intracranial Hematoma

OBJECTIVE

Outcome prediction is of paramount importance in traumatic brain injury. Our objective of conducting this prospective study was to identify the predictors needed to formulate a prognostic score.

METHODS

Clinical and radiologic characteristics of 100 patients with traumatic intracranial hematoma were analyzed. Key measurements were taken in the midbrain and pontine regions and the status of each of the 9 basal cisterns was noted, by giving a score of 1 if they were visible and 0 if not. All the predictors were analyzed for outcome.

RESULTS

Total cisternal score was found to be an independent predictor of outcome. A grade was formulated by dividing the score into 3 levels.

CONCLUSIONS

The model based on cisternal status described in the study is technically simple and conveys the information regarding the outcome to the treating neurosurgeon. Because the score obtained seems to have low interobserver variation, we believe that it can be a useful tool not only in recording data in case files and interphysician communication but also in research into traumatic brain injury.

Benefit on optimal cerebral perfusion pressure targeted treatment for traumatic brain injury patients

PURPOSE

The maintenance of patient-specific optimal cerebral perfusion pressure (CPPopt) is crucial for patients with traumatic brain injury (TBI). The goal of the study was to explore the influence of CPP declination from CPPopt value on the TBI patients' outcome.

METHODS

The CPP and cerebrovascular autoregulation (CA) monitoring of 52 TBI patients was performed. Patient-specific CPPopt has been identified and the associations between the patients' outcome and complex influence of time of CPP declination from CPPopt value, age, and the duration of CA impairment episodes has been analyzed.

RESULTS

The multiple correlation coefficient between the Glasgow outcome scale (GOS), duration of CA impairment events and percentage time, when 0<ΔCPPopt<10mmHg was r=-0.643 (P<0.001). The multiple correlation coefficients between GOS, age, and percentage time of ΔCPPopt when 0<ΔCPPopt<10mmHg was r=-0.587 (P<0.001).

CONCLUSION

The CPPopt-targeted patient-specific management might be useful for stabilizing CA in TBI patients as well as for improving their outcome. Better outcomes were obtained by maintaining CPP in light hyperperfusion condition (up to 10mmHg above CPPopt) when CPPopt is in the range of 60-80mmHg, and keeping CPP within the range of CPPopt +/-5mmHg when CPPopt is above 80mmHg.

Early Brain Edema is a Predictor of In-Hospital Mortality in Traumatic Brain Injury

BACKGROUND

Identifying patients who may progress to a poor clinical outcome will encourage earlier appropriate therapeutic interventions. Brain edema may contribute to secondary injury in traumatic brain injury (TBI) and thus, may be a useful prognostic indicator.

OBJECTIVE

We determined whether the presence of brain edema on the initial computed tomography (CT) scan of TBI patients would predict poor in-hospital outcome.

METHODS

We performed a retrospective review of all trauma patients with nonpenetrating head trauma at a Level I Trauma Center. International Classification of Diseases, Ninth Revision codes indicated the presence of brain edema and we evaluated the validity of this pragmatic assessment quantitatively in a random subset of patients. In-hospital mortality was the primary outcome variable. Univariate analysis and logistic regression identified predictors of mortality in all TBI patients and those with mild TBI.

RESULTS

Over 7200 patients were included in the study, including 6225 with mild TBI. Measurements of gray and white matter CT density verified radiological assessments of brain edema. Patients with documented brain edema had a mortality rate over 10 times that of the entire study population. With logistic regression accounting for Injury Severity Score, Glasgow Coma Scale score, other CT findings, and clinical variables, brain edema predicted an eightfold greater mortality rate in all patients (odds ratio 8.0, 95% confidence interval 4.6-14.0) and fivefold greater mortality rate for mild TBI patients (odds ratio 4.9, 95% confidence interval 2.0-11.7).

CONCLUSIONS

Brain edema is an independent prognostic variable across all categories of TBI severity. By alerting emergency physicians to patients with poor predicted clinical outcomes, this finding will drive better resource allocation, earlier intervention, and reduced patient mortality.

Subdural hematoma as a major determinant of short-term outcomes in traumatic brain injury

OBJECTIVE Early radiographic findings in patients with traumatic brain injury (TBI) have been studied in hopes of better predicting injury severity and outcome. However, prior attempts have generally not considered the various types of intracranial hemorrhage in isolation and have typically not excluded patients with potentially confounding extracranial injuries. Therefore, the authors examined the associations of various radiographic findings with short-term outcome to assess the potential utility of these findings in future prognostic models. METHODS The authors retrospectively identified 1716 patients who had experienced TBI without major extracranial injuries, and categorized them into the following TBI subtypes: subdural hematoma (SDH), traumatic subarachnoid hemorrhage, intraparenchymal hemorrhage (which included intraventricular hemorrhage), and epidural hematoma. They specifically considered isolated forms of hemorrhage, in which only 1 subtype was present. RESULTS In general, the presence of an isolated SDH was more likely to result in worse outcomes than the presence of other isolated forms of traumatic intracranial hemorrhage. Discharge to home was less likely and perihospital mortality rates were generally higher in patients with SDH. These findings were not simply related to age and were not fully captured by the admission Glasgow Coma Scale (GCS) score. The presence of SDH had a much higher sensitivity for poor outcome than the presence of other TBI subtypes, and was more sensitive for these poor outcomes than having a low GCS score (3-8). CONCLUSIONS In these ways, SDH was the most important finding associated with poor outcome, and the authors show that consideration of SDH, specifically, can augment age and GCS score in classification and prognostic models for TBI.

Outcome Prediction after Traumatic Brain Injury: Comparison of the Performance of Routinely Used Severity Scores and Multivariable Prognostic Models

OBJECTIVES

Prognosis of outcome after traumatic brain injury (TBI) is important in the assessment of quality of care and can help improve treatment and outcome. The aim of this study was to compare the prognostic value of relatively simple injury severity scores between each other and against a gold standard model - the IMPACT-extended (IMP-E) multivariable prognostic model.

MATERIALS AND METHODS

For this study, 866 patients with moderate/severe TBI from Austria were analyzed. The prognostic performances of the Glasgow coma scale (GCS), GCS motor (GCSM) score, abbreviated injury scale for the head region, Marshall computed tomographic (CT) classification, and Rotterdam CT score were compared side-by-side and against the IMP-E score. The area under the receiver operating characteristics curve (AUC) and Nagelkerke's R² were used to assess the prognostic performance. Outcomes at the Intensive Care Unit, at hospital discharge, and at 6 months (mortality and unfavorable outcome) were used as end-points.

RESULTS

Comparing AUCs and R²s of the same model across four outcomes, only little variation was apparent. A similar pattern is observed when comparing the models between each other: Variation of AUCs <±0.09 and R²s by up to ±0.17 points suggest that all scores perform similarly in predicting outcomes at various points (AUCs: 0.65-0.77; R²s: 0.09-0.27). All scores performed significantly worse than the IMP-E model (with AUC > 0.83 and R² > 0.42 for all outcomes): AUCs were worse by 0.10-0.22 (P < 0.05) and R²s were worse by 0.22-0.39 points.

CONCLUSIONS

All tested simple scores can provide reasonably valid prognosis. However, it is confirmed that well-developed multivariable prognostic models outperform these scores significantly and should be used for prognosis in patients after TBI wherever possible.

MDCT imaging of traumatic brain injury

The aim of emergency imaging is to detect treatable lesions before secondary neurological damage occurs. CT plays a primary role in the acute setting of head trauma, allowing accurate detection of lesions requiring immediate neurosurgical treatment. CT is also accurate in detecting secondary injuries and is therefore essential in follow-up. This review discusses the main characteristics of primary and secondary brain injuries.

Comparison of predictability of Marshall and Rotterdam CT scan scoring system in determining early mortality after traumatic brain injury

BACKGROUND

Marshall computed tomographic (CT) classification is widely used as a predictor of outcome. However, this grading system lacks the following variables, which are found to be useful predictors: subarachnoid/intraventricular hemorrhage, extradural hematoma, and extent of basal cistern compression. A new classification called the Rotterdam grading system, incorporating the above variables, was proposed later. In the original paper, this system was found to have superior discrimination as compared to Marshall grading, however, Rotterdam grading has not been validated widely. We aimed to compare the discriminatory power of both grading systems.

METHODS

This is a prospective study of patients with moderate and severe TBI (Glasgow coma scale (GCS) 3-12) who presented to our casualty. All the patients were followed up for 2 weeks to determine early mortality. The discriminatory power of each grading system was determined using area under the receiver operating characteristic curve (AUC).

RESULTS

A total of 134 patients, mean age 38.3 (±15.7) years, were recruited for study. The overall mortality was 11.2 %. The mean GCS of these patients was 9.6 (±2.3). There was good correlation between Marshall and Rotterdam grading, r = 0.68 (significant at 0.01 level). The Marshall CT classification had reasonable discrimination (AUC - 0.707), and Rotterdam grading had good discrimination (AUC - 0.681).

CONCLUSIONS

Both Marshal and Rotterdam grading systems are good in predicting early mortality after moderate and severe TBI. As the Rotterdam system also includes additional variables like subarachnoid hemorrhage, it may be preferable, particularly in patients with diffuse injury.