Decompressive craniectomy in neurocritical care

Decompressive craniectomy in traumatic brain injury: The intensivist's point of view

OBJETIVE

To perform a score with early clinical and radiological findings after a TBI that identifies the patients who in their subsequent evolution are going to undergo DC.

METHOD

Observational study of a retrospective cohort of patients who, after a TBI, enter the Neurocritical Section of the Intensive Care Unit of our hospital for a period of 5 years (2014-2018). Detection of clinical and radiological criteria and generation of all possible models with significant, clinically relevant and easy to detect early variables. Selection of the one with the lowest Bayesian Information Criterion and Akaike Information Criterion values for the creation of the score. Calibration and internal validation of the score using the Hosmer-Lemeshow and a bootstrapping analysis with 1000 re-samples respectively.

RESULTS

37 DC were performed in 153 patients who were admitted after a TBI. The resulting final model included Cerebral Midline Deviation, GCS and Ventricular Collapse with an Area under ROC Curve: 0.84 (95% IC 0.78-0.91) and Hosmer-Lemeshow p=0.71. The developed score detected well those patients who were going to need an early DC (first 24h) after a TBI (2.5±0.5) but not those who would need it in a later stage of their disease (1.7±0.8). However, it seems to advice us about the patients who, although not requiring an early DC are likely to need it later in their evolution (DC after 24h vs. do not require DC, 1.7±0.8 vs. 1±0.7; p=0.002).

CONCLUSION

We have developed a prognostic score using early clinical-radiological criteria that, in our environment, detects with good sensitivity and specificity those patients who, after a TBI, will require a DC.

Influence of Decompressive Craniectomy Post Evacuation of Epidural Hematoma in Comatose Patients

BACKGROUND

Epidural hematoma causing brain herniation is a major cause of mortality and morbidity after severe traumatic brain injury, even if surgical treatment is performed quickly. Decompression may be effective in decreasing intracranial pressure, but its effect on outcomes remains unclear.

METHODS

A retrospective analysis of deeply comatose patients (Glasgow Coma Scale score 3-5) who underwent surgical treatment during a 12-year period, either via osteoplastic craniotomy (OC) or decompressive craniectomy, was carried out. Patient groups were compared on the basis of demographics, admission clinical state, head computed tomography imaging characteristics, and discharge outcome.

RESULTS

A total of 60 patients were examined. The first group of 31 patients (52%) needed decompression during primary surgery. The second group of 29 patients (48%) underwent OC with evacuation of epidural hematoma without decompression. Both patient groups were similar according to age (40.9 ± 13 vs. 40.6 ± 12.5 years), Glasgow Coma Scale score before surgery (4 [3-5] vs. 4 [3-5]), hematoma thickness (based on computed tomography) (3.44 ± 1 vs. 3.36 ± 1.62 cm), and midline shift (1.42 ± 0.83 vs. 1.36 ± 0.9 cm). Mortality was more evident in the decompression group (45.2% vs. 13.8%; P = 0.008), and the Glasgow Outcome Score was also lower, 2.26 ± 1.5 versus 3.45 ± 1.5 (P = 0.003).

CONCLUSIONS

Decompressive craniectomy following the evacuation of an acute epidural hematoma in deeply comatose patients demonstrated inferior outcomes in comparison with OC. Brain injury in the decompressive craniectomy patient group was more severe (concomitant subdural hematoma, early brain ischemia, and early brain herniation), which may have influenced the outcome. Further prospective studies are needed.

Decompressive craniectomy in traumatic brain injury: the intensivist's point of view

OBJETIVE

To perform a score with early clinical and radiological findings after a TBI that identifies the patients who in their subsequent evolution are going to undergo DC.

METHOD

Observational study of a retrospective cohort of patients who, after a TBI, enter the Neurocritical Section of the Intensive Care Unit of our hospital for a period of 5 years (2014-2018). Detection of clinical and radiological criteria and generation of all possible models with significant, clinically relevant and easy to detect early variables. Selection of the one with the lowest Bayesian Information Criterion and Akaike Information Criterion values for the creation of the score. Calibration and internal validation of the score using the Hosmer-Lemeshow and a bootstrapping analysis with 1,000 re-samples respectively.

RESULTS

37 DC were performed in 153 patients who were admitted after a TBI. The resulting final model included Cerebral Midline Deviation, GCS and Ventricular Collapse with an Area under ROC Curve: 0.84 (95% IC 0.78-0.91) and Hosmer-Lemeshow p=0.71. The developed score detected well those patients who were going to need an early DC (first 24hours) after a TBI (2.5±0.5) but not those who would need it in a later stage of their disease (1.7±0.8). However, it seems to advice us about the patients who, although not requiring an early DC are likely to need it later in their evolution (DC after 24hours vs do not require DC, 1.7±0.8 vs 1±0.7; p=0.002).

CONCLUSION

We have developed a prognostic score using early clinical-radiological criteria that, in our environment, detects with good sensitivity and specificity those patients who, after a TBI, will require a DC.

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 overview of management of intracranial hypertension in the intensive care unit

Intracranial hypertension (IH) is a clinical condition commonly encountered in the intensive care unit, which requires immediate treatment. The maintenance of normal intracranial pressure (ICP) and cerebral perfusion pressure in order to prevent secondary brain injury (SBI) is the central focus of management. SBI can be detected through clinical examination and invasive and non-invasive ICP monitoring. Progress in monitoring and understanding the pathophysiological mechanisms of IH allows the implementation of targeted interventions in order to improve the outcome of these patients. Initially, general prophylactic measures such as patient's head elevation, fever control, adequate analgesia and sedation depth should be applied immediately to all patients with suspected IH. Based on specific indications and conditions, surgical resection of mass lesions and cerebrospinal fluid drainage should be considered as an initial treatment for lowering ICP. Hyperosmolar therapy (mannitol or hypertonic saline) represents the cornerstone of medical treatment of acute IH while hyperventilation should be limited to emergency management of life-threatening raised ICP. Therapeutic hypothermia could have a possible benefit on outcome. To control elevated ICP refractory to maximum standard medical and surgical treatment, at first, high-dose barbiturate administration and then decompressive craniectomy as a last step are recommended with unclear and probable benefit on outcomes, respectively. The therapeutic strategy should be based on a staircase approach and be individualized for each patient. Since most therapeutic interventions have an uncertain effect on neurological outcome and mortality, future research should focus on both studying the long-term benefits of current strategies and developing new ones.

Osteoblast and Bacterial Culture from Cryopreserved Skull Flap after Craniectomy: Laboratory Study

Objective

Cranioplasty using a cryopreserved skull flap is a wide spread practice. The most well-known complications of cranioplasty are postoperative surgical infections and bone flap resorption. In order to find biological evidence of cryopreserved cranioplasty, we investigated microorganism contamination of cryopreserved skulls and cultured osteoblasts from cryopreserved skulls.

Methods

Cryopreserved skull flaps of expired patients stored in a bone bank were used. Cryopreserved skulls were packaged in a plastic bag and wrapped with cotton cloth twice. After being crushed by a hammer, cancellous bone between the inner and outer table was obtained. The cancellous bone chips were thawed in a water bath of 30°C rapidly. After this, osteoblast culture and general microorganism culture were executed. Osteoblast cultures were done for 3 weeks. Microorganism cultures were done for 72 hours.

Results

A total of 47 cryopreserved skull flaps obtained from craniectomy was enrolled. Of the sample, 11 people were women, and the average age of patients was 55.8 years. Twenty four people had traumatic brain injuries, and 23 people had vascular diseases. Among the patients with traumatic brain injuries, two had fracture compound comminuted depressed. The duration of cryopreservation was, on average, 83.2 months (9 to 161 months). No cultured osteoblast was observed. No microorganisms were cultured.

Conclusion

In this study, neither microorganisms nor osteoblasts were cultured. The biological validity of cryopreserved skulls cranioplasty was considered low. However, the usage of cryopreserved skulls for cranioplasty is worthy of further investigation in the aspect of cost-effectiveness and risk-benefit of post-cranioplasty infection.

A population-based study on epidemiology of intensive care unit treated traumatic brain injury in Iceland

BACKGROUND

Traumatic brain injury is a worldwide health issue and a significant cause of preventable deaths and disabilities. We aimed to describe population-based data on intensive care treated traumatic brain injury in Iceland over 15 years period.

METHODS

Retrospective review of all intensive care unit admissions due to traumatic brain injury at The National University Hospital of Iceland 1999-2013. Data were collected on demographics, mechanism of injury, alcohol consumption, glasgow come scale upon admission, Injury Severity Scoring, acute physiology and chronic health evaluation II score, length of stay, interventions and mortality (defined as glasgow outcome score one). All computerized tomography scans were reviewed for Marshall score classification.

RESULTS

Intensive care unit admissions due to traumatic brain injury were 583. The incidence decreased significantly from 14/100.000/year to 12/100.000/year. Males were 72% and the mean age was 41 year. Majority of patients (42%) had severe traumatic brain injury. The most common mechanism of injury was a fall from low heights (36.3%). The mortality was 18.2%. Increasing age, injury severity score, Marshall score and acute physiology and chronic health evaluation II score are all independent risk factors for death. Glasgow coma scale was not an independent prognostic factor for outcome.

CONCLUSIONS

Incidence decreased with a shift in injury mechanism from road traffic accidents to falls and an increased rate of traumatic brain injury in older patients following a fall from standing or low heights. Mortality was higher in older patients falling from low heights than in younger patients suffering multiple injuries in road traffic accidents. Age, injury severity score, acute physiology and chronic health evaluation II score and Marshall score are good prognostic factors for outcome. Traumatic brain injury continues to be a considerable problem and the increase in severe traumatic brain injury in the middle age and older age groups after a seemingly innocent accident needs a special attention.

Traumatic Brain Injury Advances

There have been many recent advances in the management of traumatic brain injury (TBI). Research regarding established and novel therapies is ongoing. Future research must not only focus on development of new strategies but determine the long-term benefits or disadvantages of current strategies. In addition, the impact of these advances on varying severities of brain injury must not be ignored. It is hoped that future research strategies in TBI will prioritize large-scale trials using common data elements to develop large registries and databases, and leverage international collaborations.

The best marker for guiding the clinical management of patients with raised intracranial pressure-the RAP index or the mean pulse amplitude?

Raised intracranial pressure is a common problem in a variety of neurosurgical conditions including traumatic brain injury, hydrocephalus and intracranial haemorrhage. The clinical management of these patients is guided by a variety of haemodynamic, biochemical and clinical factors. However to date there is no single parameter that is used to guide clinical management of patients with raised intracranial pressure (ICP). However, the role of ICP indices, specifically the mean pulse amplitude (AMP) and RAP index [correlation coefficient (R) between AMP amplitude (A) and mean ICP pressure (P); index of compensatory reserve], as an indicator of true ICP has been investigated. Whilst the RAP index has been used both as a descriptor of neurological deterioration in TBI patients and as a way of characterising the compensatory reserve in hydrocephalus, more recent studies have highlighted the limitation of the RAP index due to the influence that baseline effect errors have on the mean ICP, which is used in the calculation of the RAP index. These studies have suggested that the ICP mean pulse amplitude may be a more accurate marker of true intracranial pressure due to the fact that it is uninfluenced by the mean ICP and, therefore, the AMP may be a more reliable marker than the RAP index for guiding the clinical management of patients with raised ICP. Although further investigation needs to be undertaken in order to fully assess the role of ICP indices in guiding the clinical management of patients with raised ICP, the studies undertaken to date provide an insight into the potential role of ICP indices to treat raised ICP proactively rather than reactively and therefore help prevent or minimise secondary brain injury.