Contribution of edema and cerebral blood volume to traumatic brain swelling in head-injured patients

Role of substance P in cerebral edema and association with an estimated specific gravity of the brain and an outcome prediction in post-traumatic cerebral edema

Purpose

The study aims to evaluate the role of substance P in cerebral edema and outcomes associated with acute TBI.

Method

Patients with acute TBI who presented within 6 h and a CT scan showed predominantly cerebral edema were included in the study. Substance P level was assessed from a serum sample collected within 6 h of trauma. We also evaluated the brain-specific gravity using the Brain View software.

Result

A total of 160 (128 male) patients were recruited. The median serum substance P concentration was 167.89 (IQR: 101.09-238.2). Substance P concentration was high in the early hours after trauma (p = 0.001). The median specific gravity of the entire brain was 1.04. Patients with a low Glasgow coma scale (GCS) at admission had a high concentration of the substance P. In the univariate analysis, low GCS, elevated serum concentrations of substance P level, high Rotterdam grade, high cerebral edema grade, a high international normalized ratio value, and high blood sugar levels were associated with poor outcomes at six months. In logistic regression analysis, low GCS at admission, high cerebral edema grade, and elevated blood sugar level were strongly associated with poor outcomes at six months. The area under the receiver operating characteristic curve was 0.884 (0.826-0.941).

Conclusion

Serum substance P is strongly associated with the severity of cerebral edema after TBI. However, brain-specific gravity does not directly correlate with posttraumatic cerebral edema severity. Serum substance P does not influence the clinical outcome of traumatic brain injury.

Modelling midline shift and ventricle collapse in cerebral oedema following acute ischaemic stroke

In ischaemic stroke, a large reduction in blood supply can lead to the breakdown of the blood-brain barrier and to cerebral oedema after reperfusion therapy. The resulting fluid accumulation in the brain may contribute to a significant rise in intracranial pressure (ICP) and tissue deformation. Changes in the level of ICP are essential for clinical decision-making and therapeutic strategies. However, the measurement of ICP is constrained by clinical techniques and obtaining the exact values of the ICP has proven challenging. In this study, we propose the first computational model for the simulation of cerebral oedema following acute ischaemic stroke for the investigation of ICP and midline shift (MLS) relationship. The model consists of three components for the simulation of healthy blood flow, occluded blood flow and oedema, respectively. The healthy and occluded blood flow components are utilized to obtain oedema core geometry and then imported into the oedema model for the simulation of oedema growth. The simulation results of the model are compared with clinical data from 97 traumatic brain injury patients for the validation of major model parameters. Midline shift has been widely used for the diagnosis, clinical decision-making, and prognosis of oedema patients. Therefore, we focus on quantifying the relationship between ICP and midline shift (MLS) and identify the factors that can affect the ICP-MLS relationship. Three major factors are investigated, including the brain geometry, blood-brain barrier damage severity and the types of oedema (including rare types of oedema). Meanwhile, the two major types (stress and tension/compression) of mechanical brain damage are also presented and the differences in the stress, tension, and compression between the intraparenchymal and periventricular regions are discussed. This work helps to predict ICP precisely and therefore provides improved clinical guidance for the treatment of brain oedema.

Pediatric spinal instrumentation

This article reviews the evolution of spinal instrumentation in the pediatric age group, starting with the cervical spine and atlantoaxial area and ending with the lower spine. The congenital and the acquired conditions which require instrumentation are described. The technical details regarding pediatric instrumentation are alluded to, and finally an attempt is made to predict the future of spinal instrumentation in this age group.

Benign Spinal Tumors

Benign spinal intradural tumors are relatively rare and include intramedullary tumors with a favorable histology such as low-grade astrocytomas and ependymomas, as well as intradural extramedullary tumors such as meningiomas and schwannomas. The effect on the neural tissue is usually a combination of mass effect and neuronal involvement in cases of infiltrative tumors. The new understanding of molecular profiling of different tumors allowed us to better define central nervous system tumors and tailor treatment accordingly. The mainstay of management of many intradural spinal tumors is maximal safe surgical resection. This goal is more achievable with intradural extramedullary tumors; yet, with a meticulous surgical approach, many of the intramedullary tumors are amenable for safe gross-total or near-total resection. The nature of these tumors is benign; hence, a different way to measure outcome success is pursued and usually depends on functional rather than oncological or survival outcomes.

A Systematic Review on Traumatic Brain Injury Pathophysiology and Role of Herbal Medicines in its Management

BACKGROUND

Traumatic brain injury (TBI) is a worldwide problem. Almost about sixtynine million people sustain TBI each year all over the world. Repetitive TBI linked with increased risk of neurodegenerative disorder such as Parkinson, Alzheimer, traumatic encephalopathy. TBI is characterized by primary and secondary injury and exerts a severe impact on cognitive, behavioral, psychological and other health problem. There were various proposed mechanism to understand complex pathophysiology of TBI but still there is a need to explore more about TBI pathophysiology. There are drugs present for the treatment of TBI in the market but there is still need of more drugs to develop for better and effective treatment of TBI, because no single drug is available which reduces the further progression of this injury.

OBJECTIVE

The main aim and objective of structuring this manuscript is to design, develop and gather detailed data regarding about the pathophysiology of TBI and role of medicinal plants in its treatment.

METHOD

This study is a systematic review conducted between January 1995 to June 2021 in which a consultation of scientific articles from indexed periodicals was carried out in Science Direct, United States National Library of Medicine (Pubmed), Google Scholar, Elsvier, Springer and Bentham.

RESULTS

A total of 54 studies were analyzed, on the basis of literature survey in the research area of TBI.

CONCLUSION

Recent studies have shown the potential of medicinal plants and their chemical constituents against TBI therefore, this review targets the detailed information about the pathophysiology of TBI and role of medicinal plants in its treatment.

Current management in the treatment of intramedullary ependymomas in children

PURPOSE

Current management of pediatric intramedullary ependymoma is extrapolated from adult series since large studies in children are unavailable. This has led us to share our experience with this rare tumor and compare it to the literature and to review and highlight important aspects of current management and point out inconsistencies.

METHODS

This is a retrospective analysis of patients with intramedullary ependymoma managed at our institution between 2004 and 2021.

RESULTS

During the study period, 5 patients were treated for intramedullary ependymoma. Cases of myxopapillary ependymoma were excluded. The mean age of our cohort was 11.2 years. We identified 4 cases of grade II ependymoma and 1 case of grade III ependymoma. Gross tumor removal (GTR) was achieved in two patients (40%) of patients. One patient was treated with radiotherapy for recurrence and two patients received chemotherapy. There were no cases of recurrence among patients treated with GTR, but in all patients treated with STR. Eighty percent of patients either improved or stayed stable neurologically. During follow-up (mean 73 months), 2 patients died of disease.

CONCLUSION

GTR and tumor grade remain the key prognostic factor of long-term tumor-free survival. Many questions prevail regarding outcomes, correct use of adjuvant therapy, and prognostic factors.

Spatial and Temporal Pattern of Ischemia and Abnormal Vascular Function Following Traumatic Brain Injury

Question

How does ¹⁵oxygen positron emission tomography characterization of cerebral physiology after traumatic brain injury inform clinical practice?

Findings

In this single-center observational cohort study of 68 patients and 27 control participants, early ischemia was common in patients, but hyperemia coexisted in different brain regions. Cerebral blood volume was consistently increased, despite low cerebral blood flow.

Meaning

Per this analysis, pathophysiologic heterogeneity indicates that bedside physiological monitoring with devices that measure global (jugular venous saturation) or focal (tissue oximetry) brain oxygenation should be interpreted with caution.

Importance

Ischemia is an important pathophysiological mechanism after traumatic brain injury (TBI), but its incidence and spatiotemporal patterns are poorly characterized.

Objective

To comprehensively characterize the spatiotemporal changes in cerebral physiology after TBI.

Design, Setting, and Participants

This single-center cohort study uses ¹⁵oxygen positron emission tomography data obtained in a neurosciences critical care unit from February 1998 through July 2014 and analyzed from April 2018 through August 2019. Patients with TBI requiring intracranial pressure monitoring and control participants were recruited.

Exposures

Cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral oxygen metabolism (CMRO₂), and oxygen extraction fraction.

Main Outcomes and Measures

Ratios (CBF/CMRO₂ and CBF/CBV) were calculated. Ischemic brain volume was compared with jugular venous saturation and brain tissue oximetry.

Results

A total of 68 patients with TBI and 27 control participants were recruited. Results from 1 patient with TBI and 7 health volunteers were excluded. Sixty-eight patients with TBI (13 female [19%]; median [interquartile range (IQR)] age, 29 [22-47] years) underwent 90 studies at early (day 1 [n = 17]), intermediate (days 2-5 [n = 54]), and late points (days 6-10 [n = 19]) and were compared with 20 control participants (5 female [25%]; median [IQR] age, 43 [31-47] years). The global CBF and CMRO₂ findings for patients with TBI were less than the ranges for control participants at all stages (median [IQR]: CBF, 26 [22-30] mL/100 mL/min vs 38 [29-49] mL/100 mL/min; P < .001; CMRO₂, 62 [55-71] μmol/100 mL/min vs 131 [101-167] μmol/100 mL/min; P < .001). Early CBF reductions showed a trend of high oxygen extraction fraction (suggesting classical ischemia), but this was inconsistent at later phases. Ischemic brain volume was elevated even in the absence of intracranial hypertension and highest at less than 24 hours after TBI (median [IQR], 36 [10-82] mL), but many patients showed later increases (median [IQR] 6-10 days after TBI, 24 [4-42] mL; across all points: patients, 10 [5-39] mL vs control participants, 1 [0-3] mL; P < 001). Ischemic brain volume was a poor indicator of jugular venous saturation and brain tissue oximetry. Patients’ CBF/CMRO₂ ratio was higher than controls (median [IQR], 0.42 [0.35-0.49] vs 0.3 [0.28-0.33]; P < .001) and their CBF/CBV ratio lower (median [IQR], 7.1 [6.4-7.9] vs 12.3 [11.0-14.0]; P < .001), suggesting abnormal flow-metabolism coupling and vascular reactivity. Patients’ CBV was higher than controls (median [IQR], 3.7 [3.4-4.1] mL/100 mL vs 3.0 [2.7-3.6] mL/100 mL; P < .001); although values were lower in patients with intracranial hypertension, these were still greater than controls (median [IQR], 3.7 [3.2-4.0] vs 3.0 [2.7-3.6] mL/100 mL; P = .002), despite more profound reductions in partial pressure of carbon dioxide (median [IQR], 4.3 [4.1-4.6] kPa vs 4.7 [4.3-4.9] kPa; P = .001).

Conclusions and Relevance

Ischemia is common early, detectable up to 10 days after TBI, possible without intracranial hypertension, and inconsistently detected by jugular or brain tissue oximetry. There is substantial between-patient and within-patient pathophysiological heterogeneity; ischemia and hyperemia commonly coexist, possibly reflecting abnormalities in flow-metabolism coupling. Increased CBV may contribute to intracranial hypertension but can coexist with abnormal CBF/CBV ratios. These results emphasize the need to consider cerebrovascular pathophysiological complexity when managing patients with TBI.

Role of MLC901 in increasing neurogenesis in rats with traumatic brain injury

Background

Traumatic brain injury is a dangerous life threatening condition. This study examines the role of MLC901 in increasing neurogenesis. The aim of this study was to demonstrate the role of MLC901 in increasing neuron cell (neurogenesis) in rat with traumatic brain injury using the synaptophysin marker.

Methods

The synaptophysin levels were measured as a marker for neuron cell (neurogenesis) of brain nerve cells in Sprague-Dawley rats aged 10–12 weeks, weighing 200–300 g. All rats (n = 10) were performed as traumatic brain injury using The Modified Marmourou Model, then they were divided into 2 group, one group was given MLC901 (n = 5) and the other group was not given MLC901 (n = 5). The synaptophysin levels in both groups were assessed after 6 weeks and also carried out an examination of immnuhistochemical from the brain tissue of both groups.

Results

There was an increase in the number of neuron cells as evidenced by synaptophysin ihc staining in the rats given MLC 901 (Neuroaid II) compared to those without MLC 901. Synaptophysin levels were lower in the control group than in the MLC 901 group (81.6, SD: 13.52 vs 118.4, SD: 12.198, p = 0.062).

Conclusion

These research suggest that MLC901 can increase neurogenesis in traumatic brain injury and also appeared as synaptophysin antibody that binding to cytoplasm of neuronal cells in the rat brain.

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Experimental study on rats with traumatic brain injury to determine the role of MLC 901 in increasing number of neuronal cells (neurogenesis) in rat with traumatic brain injury using the synaptophysin marker.

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The synaptophysin levels in both groups were assessed after 6 weeks and also carried out an examination of immnuhistochemical from the brain tissue of both groups.

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There was an increase in synaptophysin levels in the rats given MLC 901.

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MLC 901 can increase neurogenesis in traumatic brain injury.

AQP4-siRNA alleviates traumatic brain edema by altering post-traumatic AQP4 polarity reversal in TBI rats

The spatial and temporal distribution of aquaporin-4 (AQP4) expression in rat brain following brain trauma and AQP4-siRNA treatment, as well as corresponding pathological changes, were studied to explore the mechanism underlying the effect of AQP4-siRNA treatment on traumatic brain injury (TBI). The rats in the sham operation group had normal structure, with AQP4 located in the perivascular end-foot membranes and astrocytic membranes in a polarized pattern. The accelerated polarity reversal was observed in the TBI group in 1-12 h after TBI. During this period, AQP4 abundance on the astrocytic membrane is gradually increased, while AQP4 abundance on the perivascular end-foot membrane declined rapidly. Twelve hours after TBI, AQP4 expression was depolarized, showing a shift from the perivascular end-foot membrane to the astrocytic membrane. Pathological observation showed that vasogenic edema occurred immediately after TBI, at which time the extracellular space was expanded, leading to severe intracellular edema. AQP4-siRNA reduced the polarity reversal index at the early stage of TBI recovery and reduced edema, demonstrating the potential benefit of reduced AQP4 expression during recovery from TBI.

Hyaluronidase reduced edema after experimental traumatic brain injury

Cerebral edema and the subsequent increased intracranial pressure are associated with mortality and poor outcome following traumatic brain injury. Previous in vitro studies have shown that the Gibbs-Donnan effect, which describes the tendency of a porous, negatively charged matrix to attract positive ions and water, applies to brain tissue and that enzymatic reduction of the fixed charge density can prevent tissue swelling. We tested whether hyaluronidase, an enzyme that degrades the large, negatively charged glycosaminoglycan hyaluronan, could reduce brain edema after traumatic brain injury. In vivo, intracerebroventricular injection of hyaluronidase after controlled cortical impact in mice reduced edema in the ipsilateral hippocampus at 24 h by both the wet-weight/dry-weight method (78.15 ± 0.65% vs. 80.4 ± 0.46%; p < 0.01) and T₂-weighted magnetic resonance imaging (13.88 ± 3.09% vs. 29.23 ± 6.14%; p < 0.01). Hyaluronidase did not adversely affect blood-brain-barrier-integrity measured by dynamic contrast-enhanced magnetic resonance imaging, nor did hyaluronidase negatively affect functional recovery after controlled cortical impact measured with the rotarod or Morris water maze tasks. Reduction of fixed charge density by hyaluronidase was confirmed in cortical explants in vitro (5.46 ± 1.15 µg/mg vs. 7.76 ± 1.87 µg/mg; p < 0.05). These data demonstrate that targeting the fixed charge density with hyaluronidase reduced edema in an in vivo mouse model of traumatic brain injury.

Effects of caffeic acid phenethyl ester in reducing cerebral edema in rat subjects experiencing brain injury: An in vivo study

Background

A head injury is a very dangerous condition that threatens human life. This study examines the use of caffeic acid phenethyl ester (CAPE) in reducing cerebral edema in cases of head injury. The purpose of this study is to demonstrate whether CAPE can improve various parameters related to the expression of Aquaporin-4 (AQP4) mRNA and the serum AQP4 levels in rat subjects.

Methods

This is a randomized controlled study using a posttest-only control group design that uses experimental animals-specifically, male Rattus norvegicus (Sprague Dawley strain) rats aged 10-12 weeks and weighing 200-300 g. This study used a head injury model according to Marmarou (1994) with minor modifications to the animal model fixation tool. The parameters of the AQP4 mRNA were examined with real-time PCR, while serum AQP4 levels were examined with sandwich ELISA.

Results

The AQP4 mRNA expression in rats that were given CAPE was lower than those not given CAPE, both on the fourth and seventh days; serum AQP4 levels in rats that were given CAPE were also lower than those not given CAPE, both on the fourth and seventh days.

Conclusion

Administration of CAPE in a rat model with head injury can reduce cerebral edema, mediated by AQP4.

Modification of the Marmarou model in developing countries

Introduction

Head injury is an injury or wound of the brain tissue due to external forces; it can cause a decrease or change in the status of consciousness. Many head injury models have used mice as experimental animals; the Marmarou model is the most famous and the most widely-used diffuse brain injury model. In this study, we slightly modified the Marmarou model. The purpose of this study is to help researchers examining head injuries in mice, especially those in developing countries who have limited facilities and infrastructure.

Methods

This experimental research uses animals models (Rattus novergicus, strain Sprague Dawley) that fit several criteria, including male, aged 10–12 weeks, and body weight of 200–300 g. This study involves a slight modification on the tube used, with a 20 cm-long weight of 20 g. The blood samples for the following assays of ELISA and brain tissue samples were collected at 24 h and 4, 5, 6, and 7 days post-trauma.

Results

A significant effect on the brain was seen with the Marmarou model modification, at a mass weight of 20 g and height of 20 cm, with 0.04 J energy produced. Changes were also seen in the histological features of brain tissue and the serum levels of AQP-4, F2 IsoPs, MPO, and VEGF from 24 h until 7 days after trauma.

Conclusion

This report describes the development of an experimental head injury approach modifying the Marmarou model that is able to produce a diffuse brain injury model in mice.

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Head injury is an injury of the brain tissue due to external forces.

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The Marmarou model is the most famous and widely-used diffuse brain injury model in mice.

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A significant effect on the brain was seen with our modified Marmarou trauma model.

Role of CAPE in reducing oxidative stress in animal models with traumatic brain injury

Introduction

The central nervous system (CNS) is the most metabolically active organ characterized by high oxygen demand and relatively low anti-oxidative activity, which makes neurons and glia highly susceptible to damage by reactive oxygen and nitrogen byproducts as well as neurodegeneration. Free radicals are associated with secondary injuries that occur after a primary brain injury. Some of these free radical products include F2-Isoprostane (F2-IsoPs), malondialdehyde (MDA), 4-hydroxy-2-nonenal (4-HNE) and acrolein.

Methods

In this study we measured serum F2-IsoPs levels as markers of free radical activity in 10–12 week-old male Sprague-Dawley rats weighing 200–300 g, all rats (n = 10) subjected with a head injury according to the modified marmourou model, then divided into 2 groups, one group treated with CAPE (Caffeic Acid Phenethyl Ester) (n = 5) and the other not treated with CAPE (n = 5), serum levels in the two groups were compared starting from day-0 (before brain injury), day-4 and day-7.

Results

We found lower F2-IsoPs levels in the group that received the CAPE treatment compared to the group that did not receive the CAPE treatment.

Conclusion

CAPE is capable of significantly reducing oxidative stress in brain injury.

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The central nervous system (CNS) is the most metabolically active organ characterized by high oxygen demand and relatively low anti-oxidative activity.

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Free radicals are associated with secondary injuries that occur after a primary brain injury.

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Caffeic Acid Phenethyl Ester (CAPE) administration in a rat model with brain injury can reduce the formation of F2-Isoprostane (F2-IsoPs) as an indicator of oxidative stress in blood serum post-trauma.

CT-Based Classification of Acute Cerebral Edema: Association with Intracranial Pressure and Outcome

BACKGROUND AND PURPOSE

Brain edema after acute cerebral lesions may lead to raised intracranial pressure (ICP) and worsen outcome. Notwithstanding, no CT-based scoring system to quantify edema formation exists. This retrospective correlative analysis aimed to establish a valid and definite CT score quantifying brain edema after common acute cerebral lesions.

METHODS

A total of 169 CT investigations in 60 patients were analyzed: traumatic brain injury (TBI; n = 47), subarachnoid hemorrhage (SAH; n = 70), intracerebral hemorrhage (ICH; n = 42), and ischemic stroke (n = 10). Edema formation was classified as 0: no edema, 1: focal edema confined to 1 lobe, 2: unilateral edema > 1 lobe, 3: bilateral edema, 4: global edema with disappearance of sulcal relief, and 5: global edema with basal cisterns effacement. ICP and Glasgow Outcome Score (GOS) were correlated to edema formation.

RESULTS

Median ICP values were 12.0, 14.0, 14.9, 18.2, and 25.9 mm Hg in grades 1-5, respectively. Edema grading significantly correlated with ICP (r = .51; P < .0001) in focal and global cerebral edema, particularly in patients with TBI, SAH, and ICH (r = .5, P < .001; r = .5; P < .0001; r = .6, P < .0001, respectively). At discharge, 23.7% of patients achieved a GOS of 5 or 4, 65.0% reached a GOS of 3 or 2, and 11.9% died (GOS 1). CT-score of cerebral edema in all patients correlated with outcome (r = -.3, P = .046).

CONCLUSION

The proposed CT-based grading of extent of cerebral edema significantly correlated with ICP and outcome in TBI, SAH, and ICH patients and might be helpful for standardized description of CT-images and as parameter for clinical studies, for example, measuring effects of antiedematous therapies.

Decreased neutrophil levels in mice with traumatic brain injury after cape administration

Introduction

Peripheral leukocytes can worsen brain damage due to the release of cytotoxic mediators that interfere the blood brain barrier function. One of the oxidants released by activation leukocyte is hypochlorite acid (HOCl) which is formed through the myeloperoxidase (MPO)-H2O2–Cl^- system. The neuroprotective effects of an experimental anti-inflammatory drug Caffeic Acid Phenethyl Ester (CAPE) tested in a Traumatic brain injury (TBI) model using Myeloperoxidase (MPO) analysis.

Methods

This study compares the acute inflammatory response to TBI over time, as measured by MPO activity. Adult Sprague mice were treated for head trauma with marmarou model. At 24 h before trauma, all animals were blood test (n = 10) to examine MPO, then the animal was divided into 2 groups of injured animals treated with CAPE (n = 5), and those not treated with CAPE (n = 5). We used the MPO test to identify the level of polymorphonuclear leukocytes (PMNL) on day 4 and day 7.

Results

Showed an increase in PMNL infiltration in CAPE untreated animals, this change significantly (P < 0.05) decreased at group of animals treated with CAPE. MPO serum activity in the CAPE untreated group vs treated with CAPE on day 4 ± 11920410.076 (Standard deviation {SD} 895355.169) vs 6663184.485 (SD 895355.169) p < 0,05 and on day 7 ± 14223286.992 (SD 802762.401) vs 9284222.028 (SD 953098.093) p < 0,05. These data indicate that MPO activity after TBI increases on day 4 also on day 7 and improves after being treated with CAPE.

Conclusion

CAPE can reduce Neutrophil serum levels there by preventing brain damage in TBI.

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Peripheral leukocytes can worsen brain damage due to the release of cytotoxic mediators that interfere the blood brain barrier function.

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One of the oxidants released by activation leukocyte is HOCl which is formed through the MPO-H2O2–Cl-system.

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CAPE administration in mice with traumatic brain injury can inhibit the formation of myeloperoxidase as a marker of accumulated neutrophils.

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CAPE can reduce Neutrophil serum levels there by preventing brain damage in TBI.

Cerebral Edema in Traumatic Brain Injury: a Historical Framework for Current Therapy

PURPOSE OF REVIEW

The purposes of this narrative review are to (1) summarize a contemporary view of cerebral edema pathophysiology, (2) present a synopsis of current management strategies in the context of their historical roots (many of which date back multiple centuries), and (3) discuss contributions of key molecular pathways to overlapping edema endophenotypes. This may facilitate identification of important therapeutic targets.

RECENT FINDINGS

Cerebral edema and resultant intracranial hypertension are major contributors to morbidity and mortality following traumatic brain injury. Although Starling forces are physical drivers of edema based on differences in intravascular vs extracellular hydrostatic and oncotic pressures, the molecular pathophysiology underlying cerebral edema is complex and remains incompletely understood. Current management protocols are guided by intracranial pressure measurements, an imperfect proxy for cerebral edema. These include decompressive craniectomy, external ventricular drainage, hyperosmolar therapy, hypothermia, and sedation. Results of contemporary clinical trials assessing these treatments are summarized, with an emphasis on the gap between intermediate measures of edema and meaningful clinical outcomes. This is followed by a brief statement summarizing the most recent guidelines from the Brain Trauma Foundation (4th edition). While many molecular mechanisms and networks contributing to cerebral edema after TBI are still being elucidated, we highlight some promising molecular mechanism-based targets based on recent research including SUR1-TRPM4, NKCC1, AQP4, and AVP1.

SUMMARY

This review outlines the origins of our understanding of cerebral edema, chronicles the history behind many current treatment approaches, and discusses promising molecular mechanism-based targeted treatments.

Vasopressin V1a Receptors Regulate Cerebral Aquaporin 1 after Traumatic Brain Injury

Brain edema formation contributes to secondary brain damage and unfavorable outcome after traumatic brain injury (TBI). Aquaporins (AQP), highly selective water channels, are involved in the formation of post-trauma brain edema; however, their regulation is largely unknown. Because vasopressin receptors are involved in AQP-mediated water transport in the kidney and inhibition of V1a receptors reduces post-trauma brain edema formation, we hypothesize that cerebral AQPs may be regulated by V1a receptors. Cerebral Aqp1 and Aqp4 messenger ribonucleic acid (mRNA) and AQP1 and AQP4 protein levels were quantified in wild-type and V1a receptor knockout (V1a-/-) mice before and 15 min, 1, 3, 6, 12, or 24 h after experimental TBI by controlled cortical impact. In non-traumatized mice, we found AQP1 and AQP4 expression in cortical neurons and astrocytes, respectively. Experimental TBI had no effect on Aqp4 mRNA or AQP4 protein expression, but increased Aqp1 mRNA (p < 0.05) and AQP1 protein expression (p < 0.05) in both hemispheres. The Aqp1 mRNA and AQP1 protein regulation was blunted in V1a receptor knockout mice. The V1a receptors regulate cerebral AQP1 expression after experimental TBI, thereby unraveling the molecular mechanism by which these receptors may mediate brain edema formation after TBI.

Effect of AQP4-RNAi in treating traumatic brain edema: Multi-modal MRI and histopathological changes of early stage edema in a rat model

Traumatic brain injury (TBI) is one of the leading causes of mortality and permanent disabilities worldwide. Brain edema following TBI remains to be the predominant cause of mortality and disability in patients worldwide. Previous studies have reported that brain edema is closely associated with aquaporin-4 (AQP4) expression. AQP4 is a water channel protein and mediates water homeostasis in a variety of brain disorders. In the current study, a rat TBI model was established, and the features of brain edema following TBI were assessed using multimodal MRI. The results of the multimodal MRI were useful, reliable and were used to evaluate the extent and the type of brain edema following TBI. Brain edema was also successfully alleviated using an intracerebral injection of AQP4 small interfering (si)RNA. The expression of AQP4 and its role in brain edema were also examined in the present study. The AQP4 siRNA was demonstrated to downregulate AQP4 expression following TBI and reduced brain edema at the early stages of TBI (6 and 12 h). The current study revealed the MRI features of brain edema and the changes in AQP4 expression exhibited following TBI, and the results provide important information that can be used to improve the early diagnosis and treatment of brain edema.

Can Mesenchymal Stem Cells Act Multipotential in Traumatic Brain Injury?

Traumatic brain injury (TBI), a leading cause of morbidity and mortality throughout the world, will probably become the third cause of death in the world by the year 2020. Lack of effective treatments approved for TBI is a major health problem. TBI is a heterogeneous disease due to the different mechanisms of injury. Therefore, it requires combination therapies or multipotential therapy that can affect multiple targets. In recent years, mesenchymal stem cells (MSCs) transplantation has considered one of the most promising therapeutic strategies to repair of brain injuries including TBI. In these studies, it has been shown that MSCs can migrate to the site of injury and differentiate into the cells secreting growth factors and anti-inflammatory cytokines. The reduction in brain edema, neuroinflammation, microglia accumulation, apoptosis, ischemia, the improvement of motor and cognitive function, and the enhancement in neurogenesis, angiogenesis, and neural stem cells survival, proliferation, and differentiation have been indicated in these studies. However, translation of MSCs research in TBI into a clinical setting will require additional preclinical trials.

Surgically-induced brain injury: where are we now?

Neurosurgical procedures cause inevitable brain damage from the multitude of surgical manipulations utilized. Incisions, retraction, thermal damage from electrocautery, and intraoperative hemorrhage cause immediate and long-term brain injuries that are directly linked to neurosurgical operations, and these types of injuries, collectively, have been termed surgical brain injury (SBI). For the past decade, a model developed to study the underlying brain pathologies resulting from SBI has provided insight on cellular mechanisms and potential therapeutic targets. This model, as seen in a rat, mouse, and rabbit, mimics a neurosurgical operation and causes commonly encountered post-operative complications such as brain edema, neuroinflammation, and hemorrhage. In this review, we elaborate on SBI and its clinical impact, the SBI animal models and their clinical relevance, the importance of applying therapeutics before neurosurgical procedures (i.e., preconditioning), and the new direction of applying venom-derived proteins to attenuate SBI.

The Evolution of the Role of External Ventricular Drainage in Traumatic Brain Injury

External ventricular drains (EVDs) are commonly used in neurosurgery in different conditions but frequently in the management of traumatic brain injury (TBI) to monitor and/or control intracranial pressure (ICP) by diverting cerebrospinal fluid (CSF). Their clinical effectiveness, when used as a therapeutic ICP-lowering procedure in contemporary practice, remains unclear. No consensus has been reached regarding the drainage strategy and optimal timing of insertion. We review the literature on EVDs in the setting of TBI, discussing its clinical indications, surgical technique, complications, clinical outcomes, and economic considerations.

Xenografting for disease modeling of intramedullary spinal cord tumors: a systematic review

STUDY DESIGN

Systematic review.

OBJECTIVES

The overall incidence of intramedullary spinal cord tumors (IMSCT) remains low and clinical trials or standardized treatment strategies are missing. Therefore, multiple animal-based xenograft models (AXM) have been developed to foster preclinical research efforts on IMSCT. We constructed a systematic literature review to summarize and compare all AXM for IMSCT, published until April 16, 2018.

METHODS

The review was conducted using 4 independent research databases following the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. Studies were included, if they reported on surgical transplantation of tumor cells or tumor tissue to the spinal cord. Methodological study quality was assessed according to the SYRCLE (systematic review center for laboratory animal experimentation) risk of Bias tool.

RESULTS

Systematic search yielded 20 publications dealing with AXM for IMSCT. In summary, 4 tumor entities were analyzed in 23 experiments using ~337 animals, mainly investigating glioblastoma or gliosarcoma biology. Studies varied regarding the use of engrafted animals, surgical techniques and tumor burden. Most commonly authors used heterotopic, transdural injection of immortalized brain tumor cell lines (1 × 10⁵ in 5 µl) into the thoracic spinal cord of immunocompromised rats. Quality assessment demonstrated an unclear risk of bias in most cases.

CONCLUSION

Although different AXM for IMSCT have been described so far, one rat model is technically feasible, enables robust experiments and demonstrates reproducible results. However, there is a need for new AXM using orthotopic engraftment of patient-derived tumor cells and for genetically engineered animal models.

Somatosensory Evoked Potentials as a Stand-Alone Tool During Spine Surgery: An Egyptian Preliminary Report

PURPOSE

Monitoring of somatosensory evoked potentials (SSEPs) serves as an early warning system to detect spinal cord injury and is correlated with postoperative sensory findings. It is an indirect indicator of motor function. This study aimed to evaluate the usefulness of intraoperative SSEPs monitoring as a stand-alone tool during spinal surgeries when motor evoked potentials are not available, to prevent and predict new postoperative neurologic deficits. Motor evoked potentials were not used as the equipment needed to record them was not available at the time of this study.

METHODS

This study included 50 patients, aged 14 to 67 years, undergoing extramedullary manipulations, decompression of an epidural abscess or neoplasm, removal of intramedullary tumor, or arteriovenous malformation or spine correction procedures. Somatosensory evoked potentials were analyzed for latency and peak-to-peak amplitude. Critical SSEP changes were defined as a 50% decrease in amplitude or a 10% increase in latency.

RESULTS

Somatosensory evoked potentials had an overall sensitivity of 81.8%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 91.3%.

CONCLUSIONS

Intraoperative SSEPs have proved to be highly sensitive and specific for iatrogenic injury, mechanical stress caused by cord traction/compression, dural traction, lowered systemic blood pressure, and cord hypothermia. The reversibility of intraoperative SSEP changes showed a highly significant relation to the number of cases with new postoperative deficits as well as type and site of pathologic study (P = 0.00, P = 0.01, and P = 0.00, respectively) but not with the level of pathologic study (P = 0.49).

Pioglitazone Therapy and Fractures: Systematic Review and Meta- Analysis

INTRODUCTION

Thiazolidinediones are a group of synthetic medications used in type 2 diabetes treatment. Among available thiazolidinediones, pioglitazone is gaining increased attention due to its lower cardiovascular risk in type 2 diabetes mellitus sufferers and seems a promising future therapy. Accumulating evidence suggests that diabetic patients may exert bone fractures due to such treatments. Simultaneously, the female population is thought to be at greater risk. Still, the safety outcomes of pioglitazone treatment especially in terms of fractures are questionable and need to be clarified.

METHODS

We searched MEDLINE, Scopus, PsyInfo, eLIBRARY.ru electronic databases and clinical trial registries for studies reporting an association between pioglitazone and bone fractures in type 2 diabetes mellitus patients published before Feb 15, 2016. Among 1536 sources that were initially identified, six studies including 3172 patients proved relevant for further analysis.

RESULT

Pooled analysis of the included studies demonstrated that after treatment with pioglitazone patients with type 2 diabetes mellitus had no significant increase in fracture risk [odds ratio (OR): 1.18, 95% confidence interval (CI): 0.82 to 1.71, p=0.38] compared to other antidiabetic drugs or placebo. Additionally, no association was found between the risk of fractures and pioglitazone therapy duration. The gender of the patients involved was not relevant to the risk of fractures, too.

CONCLUSION

Pioglitazone treatment in diabetic patients does not increase the incidence of bone fractures. Moreover, there is no significant association between patients' fractures, their gender and the period of exposure to pioglitazone. Additional longitudinal studies need to be undertaken to obtain more detailed information on bone fragility and pioglitazone therapy.

Diffusion Magnetic Resonance Imaging Unveils the Spatiotemporal Microstructural Gray Matter Changes following Injury in the Rodent Brain

Traumatic brain injury (TBI) is associated with gray and white matter alterations in brain tissue. Gray matter alterations are not yet as well studied as those of the white matter counterpart. This work utilized T2-weighted structural imaging, diffusion tensor imaging (DTI), and diffusion kurtosis imaging to unveil the gray matter changes induced in a controlled cortical impact (CCI) mouse model of TBI at 5 h, 1 day, 3 days, 7 days, 14 days, and 30 days post-CCI. A cross-sectional histopathology approach was used to confer validity of the magnetic resonance imaging (MRI) data by performing cresyl violet staining and glial fibrillary acidic protein (GFAP) immunohistochemistry. The results demonstrated a significant increase in lesion volume up to 3 days post-injury followed by a significant decrease in the cavity volume for the period of 1 month. GFAP signals peaked on Day 7 and persisted until Day 30 in both ipsilateral and contralateral hippocampus, ipsilateral cortex, and thalamic areas. An increase in fractional anisotropy (FA) was seen at Day 7 in the pericontusional area but decreased FA in the contralateral cortex, hippocampus, and thalamus. Mean diffusivity (MD) was significantly lower in the pericontusional cortex. Increased MD and decreased mean kurtosis were limited to the injury site on Days 7 to 30 and to the contralateral hippocampus and thalamus on Days 3 and 7. This work is one of the few cross-sectional studies to demonstrate a link between MRI measures and histopathological readings to track gray matter changes in the progression of TBI.

Glibenclamide Produces Region-Dependent Effects on Cerebral Edema in a Combined Injury Model of Traumatic Brain Injury and Hemorrhagic Shock in Mice

Cerebral edema is critical to morbidity/mortality in traumatic brain injury (TBI) and is worsened by hypotension. Glibenclamide may reduce cerebral edema by inhibiting sulfonylurea receptor-1 (Sur1); its effect on diffuse cerebral edema exacerbated by hypotension/resuscitation is unknown. We aimed to determine if glibenclamide improves pericontusional and/or diffuse edema in controlled cortical impact (CCI) (5m/sec, 1 mm depth) plus hemorrhagic shock (HS) (35 min), and compare its effects in CCI alone. C57BL/6 mice were divided into five groups (n = 10/group): naïve, CCI+vehicle, CCI+glibenclamide, CCI+HS+vehicle, and CCI+HS+glibenclamide. Intravenous glibenclamide (10 min post-injury) was followed by a subcutaneous infusion for 24 h. Brain edema in injured and contralateral hemispheres was subsequently quantified (wet-dry weight). This protocol brain water (BW) = 80.4% vehicle vs. 78.3% naïve, p < 0.01) but was not reduced by glibenclamide (I%BW = 80.4%). Ipsilateral edema also developed in CCI alone (I%BW = 80.2% vehicle vs. 78.3% naïve, p < 0.01); again unaffected by glibenclamide (I%BW = 80.5%). Contralateral (C) %BW in CCI+HS was increased in vehicle (78.6%) versus naive (78.3%, p = 0.02) but unchanged in CCI (78.3%). At 24 h, glibenclamide treatment in CCI+HS eliminated contralateral cerebral edema (C%BW = 78.3%) with no difference versus naïve. By 72 h, contralateral cerebral edema had resolved (C%BW = 78.5 ± 0.09% vehicle vs. 78.3 ± 0.05% naïve). Glibenclamide decreased 24 h contralateral cerebral edema in CCI+HS. This beneficial effect merits additional exploration in the important setting of TBI with polytrauma, shock, and resuscitation. Contralateral edema did not develop in CCI alone. Surprisingly, 24 h of glibenclamide treatment failed to decrease ipsilateral edema in either model. Interspecies dosing differences versus prior studies may play an important role in these findings. Mechanisms underlying brain edema may differ regionally, with pericontusional/osmolar swelling refractory to glibenclamide but diffuse edema (via Sur1) from combined injury and/or resuscitation responsive to this therapy. TBI phenotype may mandate precision medicine approaches to treat brain edema.

Inhibition of Epac2 Attenuates Neural Cell Apoptosis and Improves Neurological Deficits in a Rat Model of Traumatic Brain Injury

Traumatic brain injury (TBI) is a major cause of mortality and disability worldwide. TBI-induced neuronal apoptosis is one of the main contributors to the secondary injury process. The aim of this study is to investigate the involvement of Exchange protein directly activated by cAMP 2 (Epac2) on TBI. We found that the expression level of Epac2 surrounding the injured area of brain in rats of TBI model was significantly increased at 12 h after TBI. The role of Epac2 in TBI was further explored by using a selective Epac2 antagonist ESI-05 to decrease the Epac2 expression. We discovered that inhibition of Epac2 could improve the neurological impairment and attenuate brain edema following TBI. The Epac2 inhibition effectively reduced neuronal cell death and P38 MAPK signaling pathway may be involved in this process. Our results suggest that inhibition of Epac2 may be a potential therapy for TBI by reducing the neural cell death, alleviating brain edema and improving neurologic deficits.

Intramedullary ependymoma: long-term outcome after surgery

BACKGROUND

Overall (OS) and progression-free survival (PFS) of patients undergoing spinal ependymoma resection has been frequently reported. Contrarily, OS and PFS of purely intramedullary ependymomas have not been clearly determined yet.

METHODS

The data of 37 patients undergoing resection of an intramedullary ependymoma (IE) from January 2000 to December 2016 were analysed retrospectively.

RESULTS

The mean age was 46 years. The male:female ratio was 24:13. The median duration of symptoms was 12 months. Sixty-two per cent of ependymomas were in the cervical, 24% in the thoracic, and 14% in the conus region in our series. The median volume was 1.3 ml. A syrinx was found in 49% and a cyst in 32%. GTR was achieved in 89%, STR in three (8%), and PR in one patient (3%). Median follow-up was 114 months. PFS was 87%, 82%, and 82% at 5, 10, and 15 years, respectively. OS was 97%, 88%, and 63% at 5, 10, and 15 years, respectively. There was a significant difference in PFS depending on the extent of resection and in OS depending on the pre-operative clinical status. There was no significant difference in OS and PFS regarding the other examined influencing factors.

CONCLUSION

GTR resection was the most important factor influencing PFS. According to our results OS of IEs is much worse than that of spinal ependymomas. Our analysis confirms that patients with good pre-operative (McCormick grade 1 and 2) clinical status have significantly better OS than patients with McCormick grade 3 and higher.

Feline spinal cord gliomas

Intraparenchymal spinal cord tumors in the cat are rarely reported and often as single case reports. In the current study, the clinical, magnetic resonance imaging (MRI), histologic, and immunohistochemical features of 7 cases of intraparenchymal spinal cord tumors in the cat are described. All cats were domestic breed, ranged from 4 to 12 years of age (median 8 years), and included spayed females (5/7) and neutered males (2/7). The duration of clinical signs ranged from 2 weeks to 3 months. MRI revealed lesions that were hyperintense on T2-weighted images with variable contrast enhancement. All 7 tumors had histologic features consistent with glial origin: 3 were astrocytic (gemistocytic or fibrous), and 2 were oligoastrocytic. Single cases of oligodendroglioma and gliomatosis cerebri were also present in the study. Glial fibrillary acidic protein immunoreactivity was robust in the tumors that were predominately astrocytic, and the gliomatosis cerebri case had extensive BLA.36 and Iba1 immunoreactivity. Ki-67 immunoreactivity was variable and most abundant in the case of malignant oligoastrocytoma. The majority of peritumoral lymphocytes were CD3 positive. The current study expands upon the known reports of spinal cord neoplasia in the cat, confirms a caudal cervical segment predilection, and includes a report of gliomatosis cerebri in the spinal cord of a cat.

Spinal ependymomas in NF2: a surgical disease?

The management of spinal cord ependymomas in Neurofibromatosis Type 2 (NF2) has traditionally been conservative, in contrast to the management of sporadic cases; the assumption being that, in the context of NF2, they did not cause morbidity. With modern management and improved outcome of other NF2 tumours, this assumption, and therefore the lack of role for surgery, has been questioned. To compare the outcome of conservative treatment of spinal ependymomas in NF2 with surgical intervention in selected patients. Retrospective review at two NF2 centers, Manchester, UK and Paris/Lille, France. In Manchester patients were managed conservatively. In France surgery was a treatment option. Inclusion in the study was based on tumor length of greater than 1.5 cm. The primary parameter assessed was acquired neurological deficit measured by the Modified McCormick Outcome Score. 24 patients from Manchester and 46 patients from France were analyzed. From Manchester, 27% of these patients deteriorated during the course of follow-up. This effectively represents the natural history of ependymomas in NF2. Of the surgical cases, 23% deteriorated postoperatively, but only 2/18 (11%) of those operated on in the NF2 specialist centers. Comparison of the two specialist centers Manchester/France showed a significantly improved outcome (P = 0.012, χ² test) in the actively surgical center. Spinal ependymomas produce morbidity. Surgery can prevent or improve this in selected cases but can itself can produce morbidity. Surgery should be considered in growing/symptomatic ependymomas, particularly in the absence of overwhelming tumor load where bevacizumab is the preferred option.

Mathematical modelling of blood-brain barrier failure and oedema

Injuries such as traumatic brain injury and stroke can result in increased blood-brain barrier (BBB) permeability. This increase may lead to water accumulation in the brain tissue resulting in vasogenic oedema. Although the initial injury may be localized, the resulting oedema causes mechanical damage and compression of the vasculature beyond the original injury site. We employ a biphasic mixture model to investigate the consequences of BBB permeability changes within a region of brain tissue and the onset of vasogenic oedema. We find that such localized changes can indeed result in brain tissue swelling and suggest that the type of damage that results (stress damage or strain damage) depends on the ability of the brain to clear oedema fluid.

FGF2 Attenuates Neural Cell Death via Suppressing Autophagy after Rat Mild Traumatic Brain Injury

Traumatic brain injury (TBI) can lead to physical and cognitive deficits, which are caused by the secondary injury process. Effective pharmacotherapies for TBI patients are still lacking. Fibroblast growth factor-2 (FGF2) is an important neurotrophic factor that can stimulate neurogenesis and angiogenesis and has been shown to have neuroprotective effects after brain insults. Previous studies indicated that FGF2's neuroprotective effects might be related to its function of regulating autophagy. The present study investigated FGF2's beneficial effects in the early stage of rat mild TBI and the underlying mechanisms. One hundred and forty-four rats were used for creating controlled cortical impact (CCI) models to simulate the pathological damage after TBI. Our results indicated that pretreatment of FGF2 played a neuroprotective role in the early stage of rat mild TBI through alleviating brain edema, reducing neurological deficits, preventing tissue loss, and increasing the number of surviving neurons in injured cortex and the ipsilateral hippocampus. FGF2 could also protect cells from various forms of death such as apoptosis or necrosis through inhibition of autophagy. Finally, autophagy activator rapamycin could abolish the protective effects of FGF2. This study extended our understanding of FGF2's neuroprotective effects and shed lights on the pharmacological therapy after TBI.

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.

Crotalus helleri venom preconditioning reduces postoperative cerebral edema and improves neurological outcomes after surgical brain injury

INTRODUCTION

Postoperative cerebral edema is a devastating complication in neurosurgical patients. Loss of blood-brain barrier integrity has been shown to lead to the development of brain edema following neurosurgical procedures. The aim of this study was to evaluate preconditioning with Crotalus helleri venom (Cv-PC) as a potential preventive therapy for reducing postoperative brain edema in the rodent SBI model. C. helleri venom is known to contain phospholipase A2 (PLA2), an enzyme upstream to cyclooxygenase-2 (COX-2) in the inflammatory cascade, acts to increase the production of inflammatory mediators, such as prostaglandins. We hypothesize that Cv-PC will downregulate the response of the COX-2 pathway to injury, thereby reducing the inflammatory response and the development of brain edema after SBI.

MATERIALS AND METHODS

75 male Sprague Dawley rats (280-330g) were divided to the following groups-naïve+vehicle, naïve+Cv-PC, sham, vehicle, Cv-PC, Cv-PC+NS398 (COX-2 inhibitor). Vehicle preconditioned and Cv-PC animals received either three daily subcutaneous doses of saline or C. helleri venom at 72h, 48h, and 24h prior to surgery. In Cv-PC+NS398 animals, NS398 was administered intraperitoneally 1h prior to each Cv-PC injection. Sham-operated animals received craniotomy only, whereas SBI animals received a partial right frontal lobectomy. Neurological testing and brain water content were assessed at 24h and 72h after SBI; COX-2 and PGE₂ expression was assessed at 24h postoperatively by Western blot and immunohistochemistry, respectively.

RESULTS

At 24h after SBI, the vehicle-treated animals were observed to have increased brain water content (83.1±0.2%) compared to that of sham animals (80.2±0.1%). The brain water content of vehicle-treated animals at 72h post-SBI was elevated at 83.3±0.2%. Cv-PC-treated animals with doses of 10% LD₅₀ had significantly reduced brain water content of 81.92±0.7% and 81.82±0.3% at 24h and 72h, respectively, after SBI compared to that of vehicle-treated animals, while Cv-PC with 5% LD₅₀ doses showed brain water content that trended lower but did not reach statistical significance. At 24h and 72h post-SBI, Cv-PC-treated animals had significantly higher neurological score than vehicle-treated animals. The COX-2 over-expression characterized in SBI was attenuated in Cv-PC-treated animals; NS398 reversed the protective effect of Cv-PC on COX-2 expression. Cv-PC tempered the over-expression of the inflammatory marker PGE₂.

CONCLUSION

Our findings indicate that Cv-PC may provide a promising therapy for reducing postoperative edema and improving neurological function after neurosurgical procedures.

Clinical and pathological outcomes after resection of intramedullary spinal cord tumors: a single-institution case series

OBJECTIVE The objective of this study was to identify clinically relevant predictors of progression-free survival and functional outcomes in patients who underwent surgery for intramedullary spinal cord tumors (ISCTs). METHODS An institutional spinal tumor registry and billing records were reviewed to identify adult patients who underwent resection of ISCTs between 1993 and 2014. Extensive data were collected from patient charts and operative notes, including demographic information, extent of resection, tumor pathology, and functional and oncological outcomes. Survival analysis was used to determine important predictors of progression-free survival. Logistic regression analysis was used to evaluate the association between an "optimal" functional outcome on the Frankel or McCormick scale at 1-year follow-up and various clinical and surgical characteristics. RESULTS The consecutive case series consisted of 63 patients (50.79% female) who underwent resection of ISCTs. The mean age of patients was 41.92 ± 14.36 years (range 17.60-75.40 years). Complete microsurgical resection, defined as no evidence of tumor on initial postoperative imaging, was achieved in 34 cases (54.84%) of the 62 patients for whom this information was available. On univariate analysis, the most significant predictor of progression-free survival was tumor histology (p = 0.0027). Patients with Grade I/II astrocytomas were more likely to have tumor progression than patients with WHO Grade II ependymomas (HR 8.03, 95% CI 2.07-31.11, p = 0.0026) and myxopapillary ependymomas (HR 8.01, 95% CI 1.44-44.34, p = 0.017). Furthermore, patients who underwent radical or subtotal resection were more likely to have tumor progression than those who underwent complete resection (HR 3.46, 95% CI 1.23-9.73, p = 0.018). Multivariate analysis revealed that tumor pathology was the only significant predictor of tumor progression. On univariate analysis, the most significant predictors of an "optimal" outcome on the Frankel scale were age (OR 0.94, 95% CI 0.89-0.98, p = 0.0062), preoperative Frankel grade (OR 4.84, 95% CI 1.33-17.63, p = 0.017), McCormick score (OR 0.22, 95% CI 0.084-0.57, p = 0.0018), and region of spinal cord (cervical vs conus: OR 0.067, 95% CI 0.012-0.38, p = 0.0023; and thoracic vs conus: OR 0.015: 95% CI 0.001-0.20, p = 0.0013). Age, tumor pathology, and region were also important predictors of 1-year McCormick scores. CONCLUSIONS Extent of tumor resection and histopathology are significant predictors of progression-free survival following resection of ISCTs. Important predictors of functional outcomes include tumor histology, region of spinal cord in which the tumor is present, age, and preoperative functional status.

Changes in cerebral hemodynamics in patients with posttraumatic diffuse brain swelling after external intraventricular drainage

PURPOSE

To investigate the changes of cerebral hemodynamics pre- and post-ventricular drainage in patients with posttraumatic acute diffuse brain swelling.

METHODS

Twenty-four cases of traumatic diffuse brain swelling were analyzed retrospectively. Patients in nonsurgical group were treated by medicine therapy. Patients in surgical group were treated by external ventricular drainage plus medicine therapy. The first CT perfusion scan was completed within 4-5 h after trauma and scanned again after 7 days. The changes of perfusion parameters in area-of-interest in two groups were analyzed and compared before and after treatment.

RESULTS

Compared with the nonsurgical group, the value of cerebral blood volume, cerebral blood flow and mean transit time in bilateral frontal temporoparietal grey matter, basal ganglia, cerebellum, and brain stem at pre- and post-therapy were increased significantly (p < 0.05) in surgical group, and consequently the prognosis of patients undergoing surgery was also better than that of nonsurgical group.

CONCLUSION

External ventricular drainage can improve cerebral perfusion and increase survival quality for the patients with posttraumatic acute diffuse brain swelling.

Outcomes following Aggressive Surgical Resection of Intra-Medullary Spinal Cord Tumours with Intra-Operative Neuro-Monitoring

Introduction:

Intra-medullary spinal cord tumours (IMCST) are relatively uncommon tumours of the central nervous system which can result in severe neurological disorder if untreated. Histologically, IMCSTs are often either biopsied or excised subtotal, but this may lead to early tumour recurrence and progressive neurological impairment. In an attempt to improve outcomes, the recent trend is to perform more radical tumour resection guided by intra-operative monitoring (IOM). However, there are no controlled studies comparing the resection of IMCSTs with or without IOM. In this single surgeon series, we analyse outcomes following optimal resection of IMCSTs in conjunction with IOM.

Methods:

In this retrospective single surgeon series, case notes and history of patients who underwent surgery between 2006–2012 at the Singapore General Hospital's Neurosurgery Department, were studied. IOM with somatosensory evoked potential (SSEP) and motor evoked potential (MEP) were utilised to facilitate optimal tumour resection. Neurological status were compared pre- and post-operatively with long-term follow-up on outcomes. Magnetic resonance imaging was used pre- and post-operatively to assess the degree of tumour resection.

Results:

Thirteen consecutive patients with IMCSTs (five males, mean age 36 years, range 12–60) underwent surgical treatment and were included in this study. Radical surgical resection was performed for 11 patients, while the remaining two had biopsies and partial debulking as frozen section showed high grade astrocytomas. Histology revealed six cases of ependymoma, five cases of astrocytoma, and one of hemangioblastoma and neuroenteric cyst. There was one case of wound infection which was treated successfully. There were no cases of cerebrospinal fluid leakage. Two patients had pre-existing spinal deformity, and underwent posterior instrumented fusion concomitantly. The neurological state improved or remained stable in 11 (85%) patients, and two patients had immediate post-operative neurological deterioration which improved subsequently with physiotherapy over one to two months. Favourable functional outcomes were observed in the majority of patients during follow-up. The patients with high grade tumours were treated with adjuvant radiotherapy post-operatively, however, they showed a poorer long-term outcome. The mean follow-up was 3.2 years from operation.

Conclusion:

Radical resection of intra-medullary tumours with IOM leads to a favourable functional outcome in selected groups of patients.

Traumatic brain injury-induced autoregulatory dysfunction and spreading depression-related neurovascular uncoupling: Pathomechanisms, perspectives, and therapeutic implications

Traumatic brain injury (TBI) is a major health problem worldwide. In addition to its high mortality (35-40%), survivors are left with cognitive, behavioral, and communicative disabilities. While little can be done to reverse initial primary brain damage caused by trauma, the secondary injury of cerebral tissue due to cerebromicrovascular alterations and dysregulation of cerebral blood flow (CBF) is potentially preventable. This review focuses on functional, cellular, and molecular changes of autoregulatory function of CBF (with special focus on cerebrovascular myogenic response) that occur in cerebral circulation after TBI and explores the links between autoregulatory dysfunction, impaired myogenic response, microvascular impairment, and the development of secondary brain damage. We further provide a synthesized translational view of molecular and cellular mechanisms involved in cortical spreading depolarization-related neurovascular dysfunction, which could be targeted for the prevention or amelioration of TBI-induced secondary brain damage.

Role of resection and adjuvant therapy in long-term disease outcomes for low-grade pediatric intramedullary spinal cord tumors

OBJECTIVE Surgical excision is the mainstay treatment for resectable low-grade intramedullary spinal cord tumors (IMSCTs) in the pediatric age group. Chemotherapy and radiation treatments are generally reserved for progressive or recurrent disease. Given the indolent nature of low-grade tumors and the potential side effects of these approaches, their long-term treatment benefits are unclear. The aim of the study was to determine long-term disease outcomes and the therapeutic roles of surgery and adjuvant therapies in pediatric patients with low-grade IMSCTs over an extended follow-up period. METHODS Case records for all pediatric patients (< 21 years of age) with a histopathological diagnosis of low-grade IMSCT were selected over a period from January 1975 to January 2010. Outcome variables including McCormick functional grade, overall survival (OS), and progression-free survival (PFS) were analyzed with respect to demographic and treatment variables. RESULTS Case records of 37 patients with low-grade IMSCTs were identified, with a mean follow-up duration of 12.3 ± 1.4 years (range 0.5-37.2 years). Low-grade astrocytomas were the most prevalent histological subtype (n = 22, 59%). Gross-total resection (GTR) was achieved in 38% of patients (n = 14). Fusion surgery was required in 62% of patients with pre- or postoperative deformity (10 of 16). On presentation, functional improvement was observed in 87% and 46% of patients in McCormick Grades I and II, respectively, and in 100%, 100%, and 75% in Grades III, IV, and V, respectively. Kaplan-Meier PFS rates were 63% at 5 years, 57% at 10 years, and 44% at 20 years. OS rates were 92% at 5 years, 80% at 10 years, and 65% at 20 years. On multivariate analysis, shunt placement (hazard ratio [HR] 0.33, p = 0.01) correlated with disease progression. There was a trend toward improved 5-year PFS in patients who received adjuvant chemotherapy and radiation therapy (RT; 55%) compared with those who did not (36%). Patients who underwent subtotal resection (STR) were most likely to undergo adjuvant therapy (HR 7.86, p = 0.02). CONCLUSIONS This extended follow-up duration in patients with low-grade IMSCTs beyond the first decade indicates favorable long-term OS up to 65% at 20 years. GTR improved PFS and was well tolerated with sustained functional improvement in the majority of patients. Adjuvant chemotherapy and RT improved PFS in patients who underwent STR. These results emphasize the role of resection as the primary treatment approach, with adjuvant therapy reserved for patients at risk for disease progression and those with residual tumor burden.

Clinical Factors for Prognosis and Treatment Guidance of Spinal Cord Astrocytoma

Study Design

Retrospective study.

Purpose

To obtain information useful in establishing treatment guidelines by evaluating baseline clinical features and treatment outcomes of patients with spinal cord astrocytoma (SCA).

Overview of Literature

The optimal management of SCA remains controversial, and there are no standard guidelines.

Methods

The study included 20 patients with low-grade and 13 with high-grade SCA surgically treated between 1989 and 2014. Patients were classified according to the extent of surgical resection. Survival was assessed using Kaplan–Meier plots and compared between groups by log-rank tests. Neurological status was defined by the modified McCormick scale and compared between groups by Mann–Whitney U tests.

Results

Surgical resection was performed for 19 of 20 low-grade (95%) and 10 of 13 high-grade (76.9%) SCA patients. Only nine patients (27.3%) underwent gross total resection, all of whom had low-grade SCA. Of all patients, 51.5% showed deteriorated neurological status compared to preoperative baseline. Median overall survival was significantly longer for low-grade SCA than that (91 months, 78% at 5 years vs. 15 months, 31% at 5 years; p=0.007). Low-grade SCA patients benefited from more aggressive resection, whereas high-grade SCA patients did not. Multivariate analysis revealed histology status (hazard ratio [HR], 0.30; 95% confidence interval [CI], 0.09–0.98; p<0.05) and postoperative neurological status (HR, 0.12; CI, 0.02–0.95; p<0.05) as independent predictors of longer overall survival. Adjuvant radiotherapy had no significant impact on survival rate. However, a trend for increased survival was observed with radiation cordotomy (RCT) in high-grade SCA patients.

Conclusions

Aggressive resection for low-grade and RCT may prolong survival. Preservation of neurological status is an important treatment goal. Given the low incidence of SCA, establishing strong collaborative, interdisciplinary, and multi-institutional study groups is necessary to define optimal treatments.

A case of an anaplastic meningioma metastasizing to the mediastinal lymph nodes

CONTEXT

Grade II and III (World Health Organization classification) meningiomas rarely develop in the spinal cord. However, we experienced a case with an anaplastic meningioma that developed in the spinal cord at the cervicothoracic junction and metastasized to the mediastinal lymph nodes. No such cases have previously been reported.

FINDINGS

The patient was a 68-year-old man who developed back pain that did not affect his daily living. He developed left lower limb paralysis, and was admitted after magnetic resonance imaging (MRI) revealed an intramedullary tumor at the level of cervical vertebra 7 and thoracic vertebra 1. Positron emission tomography revealed tracer uptake in the intramedullary tumor and the mediastinal lymph nodes, suggesting a metastatic spinal cord tumor or malignant lymphoma. A lymph node biopsy was then performed. Although the tumor was highly malignant, its primary site was not identified. Detailed examinations by several other departments revealed no abnormalities. On hospital day 30, his left lower limb paralysis deteriorated, and MRI revealed that the tumor had grown. Thus, laminaplasty, laminectomy, and tumor resection were performed. The tumor was an anaplastic meningioma that resembled mediastinal lymph node tissue, and other tumor lesions were not found. These findings suggested that an anaplastic meningioma had metastasized to the mediastinal lymph nodes. The patient did not respond to radiotherapy, and he was transferred to another hospital.

CONCLUSION

In cases of intramedullary spinal tumors with metastasis without other potential primary tumor lesions, early diagnosis and treatment should be performed while considering anaplastic meningioma.

Intramedullary spinal cord metastases: an increasingly common diagnosis

OBJECT Intramedullary spinal cord metastases (ISCM) represent a small proportion of intramedullary tumors. However, with the lifespans of patients with malignant tumors increasing, incidents of ISCM are on the rise. Due to threateningly severe disabilities in patients, accompanied by limited life expectancy, every attempt should be made to treat these tumors the same way as metastases elsewhere in the CNS, with the goal of complete removal of the ISCM and preservation of neurological functions. The object of this study is to retrospectively analyze the experiences of 22 patients who were surgically treated for ISCM over a 22-year period. METHODS Hospital charts of 22 patients, who were surgically treated for ISCM between 1992 and 2014, were reviewed retrospectively. Demographic data, histopathological diagnoses of primary cancer, chronological sequence of the disease, and neurological status using the simplified McCormick functional classification were collected and reanalyzed. RESULTS The most frequent histology was metastasis of lung cancer, followed by brain and breast cancers. The time span from primary cancer diagnosis to the development of symptomatic spinal metastases ranged from 0 to 285 months, with a mean interval of 38 months. The leading presenting sign was dysesthesia (77% of the population), followed by paresis (68%). Only 5 patients (23%) showed urinary retention. Initial performance status represented by the McCormick Scale was on average 2.47. Total or near-total removal was achieved in 87% of cases. Compared with the clinical status 1-2 days after surgery, there was an improvement in the McCormick Scale grade at the last follow-up from 2.47 to 2.12 (p = 0.009). Likewise, an improvement was detected when comparing the preoperative status with the last follow-up (from 2.45 to 2.12; p = 0.029). The mean survival time after surgery was 11.6 months. CONCLUSIONS These results suggest that surgery for intramedullary metastases-with all of the challenges of a rare and potentially risky procedure-can be beneficial to patients with advanced stages of cancer. Surgery can be performed with minimal new morbidity and results in maintaining neurological performance status.

Evidence for cerebral edema, cerebral perfusion, and intracranial pressure elevations in acute mountain sickness

INTRODUCTION

We hypothesized that cerebral alterations in edema, perfusion, and/or intracranial pressure (ICP) are related to the development of acute mountain sickness (AMS).

METHODS

To vary AMS, we manipulated ambient oxygen, barometric pressure, and exercise duration. Thirty-six subjects were tested before, during and after 8 h exposures in (1) normobaric normoxia (NN; 300 m elevation equivalent); (2) normobaric hypoxia (NH; 4400 m equivalent); and (3) hypobaric hypoxia (HH; 4400 m equivalent). After a passive 15 min ascent, each subject participated in either 10 or 60 min of cycling exercise at 50% of heart rate reserve. We measured tissue absorption and scattering via radio-frequency near-infrared spectroscopy (NIRS), optic nerve sheath diameter (ONSD) via ultrasound, and AMS symptoms before, during, and after environmental exposures.

RESULTS

We observed significant increases in NIRS tissue scattering of 0.35 ± 0.11 cm(-1) (P = 0.001) in subjects with AMS (i.e., AMS+), consistent with mildly increased cerebral edema. We also noted a small, but significant increase in total hemoglobin concentrations with AMS+, 3.2 ± 0.8 μmolL(-1) (P < 0.0005), consistent with increased cerebral perfusion. No effect of exercise duration was found, nor did we detect differences between NH and HH. ONSD assays documented a small but significant increase in ONSD (0.11 ± 0.02 mm; P < 0.0005) with AMS+, suggesting mildly elevated ICP, as well as further increased ONSD with longer exercise duration (P = 0.005).

CONCLUSION

In AMS+, we found evidence of cerebral edema, elevated cerebral perfusion, and elevated ICP. The observed changes were small but consistent with the reversible nature of AMS.

Intramedullary Spinal Cord Tumors: Part II-Management Options and Outcomes

Study Design Broad narrative review. Objectives Intramedullary spinal cord tumors (IMSCT) are uncommon lesions that can affect any age group or sex. However, numerous IMSCT exist and the clinical course of each tumor varies. The following article addresses the various management options and outcomes in patients with IMSCT. Methods An extensive review of the peer-reviewed literature was performed, addressing management options and clinical outcomes of patients with IMSCT. Results Early diagnosis and intervention are essential to obtain optimal functional outcome. Each IMSCT have specific imaging characteristics, which help in the clinical decision-making and prognostication. A comprehension of the tumor pathology and the clinical course associated with each tumor can allow for the proper surgical and nonsurgical management of these tumors, and reduce any associated morbidity and mortality. Recent advances in the operative management of such lesions have increased the success rate of tumor removal while minimizing iatrogenic-related trauma to the patient and, in tandem, improving patient outcomes. Conclusions Awareness and understanding of IMSCT is imperative to design proper management and obtain optimal patient outcomes. Meticulous operative technique and the use of surgical adjuncts are essential to accomplish proper tumor removal, diminish the risk of recurrence, and preserve neurologic function. Operative management of IMSCT should be individualized and based on tumor type, location, and dimensional extensions. To assist with preoperative and intraoperative decision-making, a general algorithm is provided.

The 100 most-cited articles in spinal oncology

OBJECTIVE The authors' objective was to identify the 100 most-cited research articles in the field of spinal oncology. METHODS The Thomson Reuters Web of Science service was queried for the years 1864-2015 without language restrictions. Articles were sorted in descending order of the number of times they were cited by other studies, and all titles and abstracts were screened to identify the research areas of the top 100 articles. Levels of evidence were assigned on the basis of the North American Spine Society criteria. RESULTS The authors identified the 100 most-cited articles in spinal oncology, which collectively had been cited 20,771 times at the time of this writing. The oldest article on this top 100 list had been published in 1931, and the most recent in 2008; the most prolific decade was the 1990s, with 34 articles on this list having been published during that period. There were 4 studies with Level I evidence, 3 with Level II evidence, 9 with Level III evidence, 70 with Level IV evidence, and 2 with Level V evidence; levels of evidence were not assigned to 12 studies because they were not on therapeutic, prognostic, or diagnostic topics. Thirty-one unique journals contributed to the 100 articles, with the Journal of Neurosurgery contributing most of the articles (n = 25). The specialties covered included neurosurgery, orthopedic surgery, neurology, radiation oncology, and pathology. Sixty-seven articles reported clinical outcomes. The most common country of article origin was the United States (n = 62), followed by Canada (n = 8) and France (n = 7). The most common topics were spinal metastases (n = 35), intramedullary tumors (n = 18), chordoma (n = 17), intradural tumors (n = 7), vertebroplasty/kyphoplasty (n = 7), primary bone tumors (n = 6), and others (n = 10). One researcher had authored 6 studies on the top 100 list, and 7 authors had 3 studies each on this list. CONCLUSIONS This study identified the 100 most-cited research articles in the area of spinal oncology. The studies highlighted the multidisciplinary and multimodal nature of spinal tumor management. Recognition of historical articles may guide future spinal oncology research.

Surgical Outcomes of High-Grade Spinal Cord Gliomas

Study Design

A retrospective study.

Purpose

The purpose of this study was to obtain useful information for establishing the guidelines for treating high-grade spinal cord gliomas.

Overview of Literature

The optimal management of high-grade spinal cord gliomas remains controversial. We report the outcomes of the surgical management of 14 high-grade spinal glioma.

Methods

We analyzed the outcomes of 14 patients with high-grade spinal cord gliomas who were surgically treated between 1989 and 2012. Survival was charted with the Kaplan-Meier plots and comparisons were made with the log-rank test.

Results

None of the patients with high-grade spinal cord gliomas underwent total resection. Subtotal resection was performed in two patients, partial resection was performed in nine patients, and open biopsy was performed in three patients. All patients underwent postoperative radiotherapy and six patients further underwent radiation cordotomy. The median survival time for patients with high-grade spinal cord gliomas was 15 months, with a 5-year survival rate of 22.2%. The median survival time for patients with World Health Organization grade III tumors was 25.5 months, whereas the median survival time for patients with glioblastoma multiforme was 12.5 months. Both univariate and multivariate Cox proportional hazards models demonstrated a significant effect only in the group that did not include cervical cord lesion as a factor associated with survival (p=0.04 and 0.03).

Conclusions

The surgical outcome of patients diagnosed with high-grade spinal cord gliomas remains poor. Notably, only the model which excluded cervical cord lesions as a factor significantly predicted survival.

Gradual and controlled decompression for brain swelling due to severe head injury

Patients suffering from uncontrollable intracranial hypertension due to posttraumatic brain swelling (BS) generally either die or survive in an extremely disabled state. Decompressive craniectomy (DC) with dural augmentation may be the best method to assist these patients. However, the efficacy of DC on functional outcomes remains controversial. One of the factors contributing to poor outcomes could be intraoperative brain extrusion, which is an acute potential complication of DC. The authors have adopted a new surgical technique for traumatic BS that can prevent and control massive intraoperative BS (IOS). In the past 3 years, the authors have used a unique technique, called "gradual and controlled decompression", in the treatment of posttraumatic BS. This procedure consists of creating numerous small dural openings and removing clots; enlarging fenestration in the frontal and temporal basal regions to detect and treat brain contusion; making U-shaped, discontinuous, small dural incisions around the circumference of the craniotomy; and performing an augmentation duraplasty through the discontinuous small opening with dural prosthetic substances. This technique has been employed in 23 patients suffering from posttraumatic BS. In all cases, IOS was prevented and controlled through gradual stepwise decompression, and expanded duraplasty was performed successfully. This new surgical approach for posttraumatic BS can prevent severe extrusion of the brain through the craniotomy defect and allows the gradual and gentle release of the subdural space. Further clinical studies should be conducted to estimate the impact of this new technique on morbidity and mortality rates.