The NCX1 calcium exchanger is implicated in delayed axotomy after peripheral nerve stretch injury.

BACKGROUND AND AIMS: After peripheral nerve stretch injury, most degenerating axons are thought to become disconnected at the time of injury, referred to as primary axotomy. The possibility of secondary axotomy-a delayed and potentially reversible form of disconnection-has not been evaluated. Here, we investigated secondary axotomy in a rat model of sciatic nerve stretch injury. We also evaluated whether axon sparing and functional improvement results from pharmacological blockade of the sodium-calcium exchanger 1 (NCX1), which is widely believed to contribute to traumatic axon degeneration but was previously only investigated in vitro. METHODS: We studied peripheral nerve secondary axotomy in a clinically relevant rat model of sciatic nerve rapid stretch injury with immunolabeling and fluorescence microscopy. The role of NCX1 in secondary axotomy was studied with pharmacological inhibition with SEA0400 and immunolabeling, immunoblot, and behavioral assays. RESULTS: We found that early after injury, many axons remained in-continuity and that degeneration of axons was delayed, consistent with the occurrence of secondary axotomy. ßAPP, a marker of secondary axotomy, accumulated at regions of axon swelling and disconnection, and NCX1 was upregulated and co-localized to ßAPP axonal swellings. Pharmacological blockade of NCX1 after injury reduced calpain activation, proteolytic degradation of neurofilaments, ßAPP accumulation, distal axon degeneration, and improved hindlimb function. INTERPRETATION: Our data demonstrate a major role for secondary axotomy in peripheral nerve stretch injury and identify NCX1 as a promising therapeutic target to reduce secondary axotomy and improve functional outcome after nerve injury.

Emerging Pharmacological Treatments for Cerebral Edema: Evidence from Clinical Studies.

Cerebral edema, a common and often fatal companion to most forms of acute central nervous system disease, has been recognized since the time of ancient Egypt. Unfortunately, our therapeutic armamentarium remains limited, in part due to historic limitations in our understanding of cerebral edema pathophysiology. Recent advancements have led to a number of clinical trials for novel therapeutics that could fundamentally alter the treatment of cerebral edema. In this review, we discuss these agents, their targets, and the data supporting their use, with a focus on agents that have progressed to clinical trials.

Intracranial and Blood Pressure Variability and In-Hospital Outcomes in Intracranial Device-Monitored Patients with Spontaneous Intracerebral Hemorrhage.

BACKGROUND: Spontaneous intracerebral hemorrhage (sICH) is a major health concern and has high mortality rates up to 52%. Despite a decrease in its incidence, fatality rates remain unchanged; understanding and preventing of factors associated with mortality and treatments for these are needed. Blood pressure variability (BPV) has been shown to be a potential modifiable factor associated with clinical outcomes in patients with traumatic intracerebral hemorrhage and sICH. Few data are available on the effect of intracranial pressure (ICP) variability (ICPV) and outcomes in patients with sICH. The goal of our study was to investigate the association between ICPV and BPV during the first 24 h of intensive care unit (ICU) admission and external ventricular drain (EVD) placement, and mortality in patients with sICH who were monitored with an EVD. METHODS: We conducted a single-center retrospective study of adult patients admitted to an ICU with a diagnosis of sICH who required EVD placement during hospitalization. We excluded patients with ICH secondary to other pathological conditions such as trauma, underlying malignancy, or arteriovenous malformation. Blood pressure and ICP measurements were collected and recorded hourly during the first 24 h of ICU admission and EVD placement, respectively. Measures of variability used were standard deviation (SD) and successive variation (SV). Primary outcome of interest was in-hospital mortality, and secondary outcomes were hematoma expansion and discharge home (a surrogate for good functional outcome at discharge). Descriptive statistics and multivariable logistic regressions were performed. RESULTS: We identified 179 patients with sICH who required EVD placement. Of these, 52 (29%) patients died, 121 (68%) patients had hematoma expansion, and 12 (7%) patients were discharged home. Patient's mean age (± SD) was 56 (± 14), and 87 (49%) were women. The mean opening ICP (± SD) was 21 (± 8) and median ICH score (interquartile range) was 2 (2-3). Multivariable logistic regression found an association between ICP-SV and ICP-SD and hematoma expansion (odds ratio 1.6 [1.03-2.30], p = 0.035 and odds ratio 0.77 [0.63-0.93] p = 0.009, respectively). CONCLUSIONS: Our study found an association between ICPV and hematoma expansion in patients with sICH monitored with an EVD. Measures of ICPV relating to rapid changes in ICP (ICP-SV) were associated with a higher odds of hematoma expansion, whereas measures relating to tight control of ICP (ICP-SD) were associated with a lower odds of hematoma expansion. One measure of BPV, sytolic blood pressure maximum-minimum (SBP max-min), was found to be weakly associated with discharge home (a surrogate for good functional outcome at hospital discharge). More research is needed to support these findings.

When the Blood Hits Your Brain: The Neurotoxicity of Extravasated Blood.

Hemorrhage in the central nervous system (CNS), including intracerebral hemorrhage (ICH), intraventricular hemorrhage (IVH), and aneurysmal subarachnoid hemorrhage (aSAH), remains highly morbid. Trials of medical management for these conditions over recent decades have been largely unsuccessful in improving outcome and reducing mortality. Beyond its role in creating mass effect, the presence of extravasated blood in patients with CNS hemorrhage is generally overlooked. Since trials of surgical intervention to remove CNS hemorrhage have been generally unsuccessful, the potent neurotoxicity of blood is generally viewed as a basic scientific curiosity rather than a clinically meaningful factor. In this review, we evaluate the direct role of blood as a neurotoxin and its subsequent clinical relevance. We first describe the molecular mechanisms of blood neurotoxicity. We then evaluate the clinical literature that directly relates to the evacuation of CNS hemorrhage. We posit that the efficacy of clot removal is a critical factor in outcome following surgical intervention. Future interventions for CNS hemorrhage should be guided by the principle that blood is exquisitely toxic to the brain.

SUR1-TRPM4 and AQP4 form a heteromultimeric complex that amplifies ion/water osmotic coupling and drives astrocyte swelling.

Astrocyte swelling occurs after central nervous system injury and contributes to brain swelling, which can increase mortality. Mechanisms proffered to explain astrocyte swelling emphasize the importance of either aquaporin-4 (AQP4), an astrocyte water channel, or of Na+ -permeable channels, which mediate cellular osmolyte influx. However, the spatio-temporal functional interactions between AQP4 and Na+ -permeable channels that drive swelling are poorly understood. We hypothesized that astrocyte swelling after injury is linked to an interaction between AQP4 and Na+ -permeable channels that are newly upregulated. Here, using co-immunoprecipitation and Förster resonance energy transfer, we report that AQP4 physically co-assembles with the sulfonylurea receptor 1-transient receptor potential melastatin 4 (SUR1-TRPM4) monovalent cation channel to form a novel heteromultimeric water/ion channel complex. In vitro cell-swelling studies using calcein fluorescence imaging of COS-7 cells expressing various combinations of AQP4, SUR1, and TRPM4 showed that the full tripartite complex, comprised of SUR1-TRPM4-AQP4, was required for fast, high-capacity transmembrane water transport that drives cell swelling, with these findings corroborated in cultured primary astrocytes. In a murine model of brain edema involving cold-injury to the cerebellum, we found that astrocytes newly upregulate SUR1-TRPM4, that AQP4 co-associates with SUR1-TRPM4, and that genetic inactivation of the solute pore of the SUR1-TRPM4-AQP4 complex blocked in vivo astrocyte swelling measured by diolistic labeling, thereby corroborating our in vitro functional studies. Together, these findings demonstrate a novel molecular mechanism involving the SUR1-TRPM4-AQP4 complex to account for bulk water influx during astrocyte swelling. These findings have broad implications for the understanding and treatment of AQP4-mediated pathological conditions.

Salutary effects of glibenclamide during the chronic phase of murine experimental autoimmune encephalomyelitis.

BACKGROUND: In multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), inflammation is perpetuated by both infiltrating leukocytes and astrocytes. Recent work implicated SUR1-TRPM4 channels, expressed mostly by astrocytes, in murine EAE. We tested the hypothesis that pharmacological inhibition of SUR1 during the chronic phase of EAE would be beneficial. METHODS: EAE was induced in mice using myelin oligodendrocyte glycoprotein (MOG) 35-55. Glibenclamide (10 µg/day) was administered beginning 12 or 24 days later. The effects of treatment were determined by clinical scoring and tissue examination. Drug within EAE lesions was identified using bodipy-glibenclamide. The role of SUR1-TRPM4 in primary astrocytes was characterized using patch clamp and qPCR. Demyelinating lesions from MS patients were studied by immunolabeling and immunoFRET. RESULTS: Administering glibenclamide beginning 24 days after MOG35-55 immunization, well after clinical symptoms had plateaued, improved clinical scores, reduced myelin loss, inflammation (CD45, CD20, CD3, p65), and reactive astrocytosis, improved macrophage phenotype (CD163), and decreased expression of tumor necrosis factor (TNF), B-cell activating factor (BAFF), chemokine (C-C motif) ligand 2 (CCL2) and nitric oxide synthase 2 (NOS2) in lumbar spinal cord white matter. Glibenclamide accumulated within EAE lesions, and had no effect on leukocyte sequestration. In primary astrocyte cultures, activation by TNF plus IFNγ induced de novo expression of SUR1-TRPM4 channels and upregulated Tnf, Baff, Ccl2, and Nos2 mRNA, with glibenclamide blockade of SUR1-TRPM4 reducing these mRNA increases. In demyelinating lesions from MS patients, astrocytes co-expressed SUR1-TRPM4 and BAFF, CCL2, and NOS2. CONCLUSIONS: SUR1-TRPM4 may be a druggable target for disease modification in MS.

Mechanisms of astrocyte-mediated cerebral edema.

Cerebral edema formation stems from disruption of blood brain barrier (BBB) integrity and occurs after injury to the CNS. Due to the restrictive skull, relatively small increases in brain volume can translate into impaired tissue perfusion and brain herniation. In excess, cerebral edema can be gravely harmful. Astrocytes are key participants in cerebral edema by virtue of their relationship with the cerebral vasculature, their unique compliment of solute and water transport proteins, and their general role in brain volume homeostasis. Following the discovery of aquaporins, passive conduits of water flow, aquaporin 4 (AQP4) was identified as the predominant astrocyte water channel. Normally, AQP4 is highly enriched at perivascular endfeet, the outermost layer of the BBB, whereas after injury, AQP4 expression disseminates to the entire astrocytic plasmalemma, a phenomenon termed dysregulation. Arguably, the most important role of AQP4 is to rapidly neutralize osmotic gradients generated by ionic transporters. In pathological conditions, AQP4 is believed to be intimately involved in the formation and clearance of cerebral edema. In this review, we discuss aquaporin function and localization in the BBB during health and injury, and we examine post-injury ionic events that modulate AQP4-dependent edema formation.

A longitudinal evaluation of diffusion kurtosis imaging in patients with mild traumatic brain injury.

PRIMARY OBJECTIVE: To investigate longitudinal diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) changes in white and grey matter in patients with mild traumatic brain injury (mTBI). RESEARCH DESIGN: A prospective case-control study. METHODS AND PROCEDURES: DKI data was obtained from 24 patients with mTBI along with cognitive assessments within 10 days, 1 month and 6 months post-injury and compared with age-matched control (n» 24). Fractional anisotropy (FA), mean diffusivity (MD), radial diffusion (l(r)), mean kurtosis (MK) and radial kurtosis (Kr) were extracted from the thalamus, internal capsule and corpus callosum. MAIN OUTCOMES AND RESULTS: Results demonstrate reduced Kr and MK in the anterior internal capsule in patients with mTBI across the three visits, and reduced MK in the posterior internal capsule during the 10 day time point. Correlations were observed between the change in MK or Kr between 1­6 months and the improvements in cognition between the 1 and 6 month visits in the thalamus, internal capsule and corpus callosum. CONCLUSIONS: These data demonstrate that DKI may be sensitive in tracking pathophysiological changes associated with mTBI and may provide additional information to conventional DTI parameters in evaluating longitudinal changes following TBI.

Complications Associated with Decompressive Craniectomy: A Systematic Review.

Decompressive craniectomy (DC) has been used for many years in the management of patients with elevated intracranial pressure and cerebral edema. Ongoing clinical trials are investigating the clinical and cost effectiveness of DC in trauma and stroke. While DC has demonstrable efficacy in saving life, it is accompanied by a myriad of non-trivial complications that have been inadequately highlighted in prospective clinical trials. Missing from our current understanding is a comprehensive analysis of all potential complications associated with DC. Here, we review the available literature, we tabulate all reported complications, and we calculate their frequency for specific indications. Of over 1500 records initially identified, a final total of 142 eligible records were included in our comprehensive analysis. We identified numerous complications related to DC that have not been systematically reviewed. Complications were of three major types: (1) Hemorrhagic (2) Infectious/Inflammatory, and (3) Disturbances of the CSF compartment. Complications associated with cranioplasty fell under similar major types, with additional complications relating to the bone flap. Overall, one of every ten patients undergoing DC may suffer a complication necessitating additional medical and/or neurosurgical intervention. While DC has received increased attention as a potential therapeutic option in a variety of situations, like any surgical procedure, DC is not without risk. Neurologists and neurosurgeons must be aware of all the potential complications of DC in order to properly advise their patients.

Nerve Transfer Surgery in Acute Flaccid Myelitis: Prognostic Factors, Long-Term Outcomes, Comparison With Natural History.

BACKGROUND: Nerve transfer surgery is sometimes offered to patients with acute flaccid myelitis (AFM). The objectives of this study were to evaluate surgical efficacy, assess which clinical and neurophysiological data are valuable for preoperative planning, and report long-term outcomes. METHODS: This is a single-center, retrospective case series of patients with AFM who received nerve transfer surgery. All patients had preoperative electromyography and nerve conduction studies (EMG/NCS). Matched control muscles that did not receive nerve transfer surgery were defined in the same cohort. RESULTS: Ten patients meeting inclusion criteria received a total of 23 nerve transfers (19 upper extremity, four lower extremity). The mean age at symptom onset was 3.8 years, surgery was 0.5 to 1.25 years after diagnosis, and mean follow-up was 2.3 years (range 1.3 to 4.5 years). Among muscles with preoperative strength Medical Research Council (MRC) grade 0, muscles receiving nerve transfers performed significantly better than those that did not (MRC grade 2.17 ± 0.42 vs 0 ± 0, respectively, P = 0.0001). Preoperative EMG/NCS predicted worse outcomes in recipient muscles with more abundant acute denervation potentials (P = 0.0098). Donor nerves found to be partially denervated performed equally well as unaffected nerves. Limited data suggested functional improvement accompanying strength recovery. CONCLUSIONS: Nerve transfer surgery is an effective strategy to restore strength for patients with AFM with persistent, severe motor deficits. Postoperative outcomes in patients with complete paralysis are better than the natural history of disease. This study demonstrates the utility of preoperative clinical and electrophysiological data in guiding patient selection for nerve transfer surgery.

Acute Development of Traumatic Intracranial Aneurysms After Civilian Gunshot Wounds to the Head.

In previous studies, the incidence of traumatic intracranial aneurysms (TICAs) after civilian gunshot wound to the head (cGSWH) was ∼3%. Given the use of delayed vessel imaging, we hypothesize that a significant fraction of TICAs is missed on initial non-contrasted scans. This study was designed to characterize acute TICAs using admission computed tomographic angiography (aCTA) in cGSWH. Over the period from 2017 to 2022, 341 patients were admitted to R. Adams Cowley Shock Trauma Center with cGSWH; 136 subjects had aCTA ∼3 (standard deviation [SD] 3.5) h post-injury. Demographics, clinical findings, imaging techniques, endovascular/surgical interventions, and outcomes were analyzed. Mean age was 34.7 (SD 13.1), male:female ratio was 120:16. Average admission Glasgow Coma Scale (GCS) score was 6 (SD 3.9). Entry site was frontal in 41, temporal in 55, parietal in 18, occipital in 6, suboccipital in 9, temporo-parietal in 1, and frontobasal-temporal in 6. Projectiles crossed multiple dural compartments in 76 (55%) patients. 35 TICAs were diagnosed in 28 subject: 24 were located along the middle cerebral artery (MCA), 6 in the anterior cerebral artery (ACA), 3 in the internal carotid artery (ICA), 1 in the posterior cerebral artery (PCA), and 1 in the middle meningeal artery (MMA). Eleven TICAs resolved spontaneously in nine patients. Eight aneurysms were treated by endovascular means, two via combined endovascular/open approaches. Forty-nine patients died, 10 of whom had 15 TICAs. Eighty patients developed intracerebral hematoma s (ICHs). Regression models showed that the presence of an ICH was the main predictor of TICA in cGSWH. Larger ICHs (average 22.3 cc vs. 9.4 cc in patients with and without aneurysms, respectively) in patients with cGSWH suggest hidden TICAs. Nearly 30% of patients had spontaneous resolution within 1 week. When CTA was performed acutely, TICAs were 10 times more frequent in cGSWH than in previous literature, and those patients were more likely to proceed to surgery. Almost one third of patients in this series died from the devastating effects of cGSWH.

A Mouse Model of Temporal Lobe Contusion.

Trauma to the brain can induce a contusion characterized by a discrete intracerebral or diffuse interstitial hemorrhage. In humans, "computed tomography-positive," that is, hemorrhagic, temporal lobe contusions (tlCont) have unique sequelae. TlCont confers significantly increased odds for moderate or worse disability and the inability to return to baseline work capacity compared to intra-axial injuries in other locations. Patients with tlCont are at elevated risks of memory dysfunction, anxiety, and post-traumatic epilepsy due to involvement of neuroanatomical structures unique to the temporal lobe including the amygdala, hippocampus, and ento-/perirhinal cortex. Because of the relative inaccessibility of the temporal lobe in rodents, no preclinical model of tlCont has been described, impeding progress in elucidating the specific pathophysiology unique to tlCont. Here, we present a minimally invasive mouse model of tlCont with the contusion characterized by a traumatic interstitial hemorrhage. Mortality was low and sensorimotor deficits (beam walk, accelerating rotarod) resolved completely within 3-5 days. However, significant deficits in memory (novel object recognition, Morris water maze) and anxiety (elevated plus maze) persisted at 14-35 days and nonconvulsive electroencephalographic seizures and spiking were significantly increased in the hippocampus at 7-21 days. Immunohistochemistry showed widespread astrogliosis and microgliosis, bilateral hippocampal sclerosis, bilateral loss of hippocampal and cortical inhibitory parvalbumin neurons, and evidence of interhemispheric connectional diaschisis involving the fiber bundle in the ventral corpus callosum that connects temporal lobe structures. This model may be useful to advance our understanding of the unique features of tlCont in humans.

Brain Swelling versus Infarct Size: A Problematizing Review.

In human stroke, brain swelling is an important predictor of neurological outcome and mortality, yet treatments to reduce or prevent brain swelling are extremely limited, due in part to an inadequate understanding of mechanisms. In preclinical studies on cerebroprotection in animal models of stroke, historically, the focus has been on reducing infarct size, and in most studies, a reduction in infarct size has been associated with a corresponding reduction in brain swelling. Unfortunately, such findings on brain swelling have little translational value for treating brain swelling in patients with stroke. This is because, in humans, brain swelling usually becomes evident, either symptomatically or radiologically, days after the infarct size has stabilized, requiring that the prevention or treatment of brain swelling target mechanism(s) that are independent of a reduction in infarct size. In this problematizing review, we highlight the often-neglected concept that brain edema and brain swelling are not simply secondary, correlative phenomena of stroke but distinct pathological entities with unique molecular and cellular mechanisms that are worthy of direct targeting. We outline the advances in approaches for the study of brain swelling that are independent of a reduction in infarct size. Although straightforward, the approaches reviewed in this study have important translational relevance for identifying novel treatment targets for post-ischemic brain swelling.

Intracellular pH measurements using perfluorocarbon nanoemulsions.

We report the synthesis and formulation of unique perfluorocarbon (PFC) nanoemulsions enabling intracellular pH measurements in living cells via fluorescent microscopy and flow cytometry. These nanoemulsions are formulated to readily enter cells upon coincubation and contain two cyanine-based fluorescent reporters covalently bound to the PFC molecules, specifically Cy3-PFC and CypHer5-PFC conjugates. The spectral and pH-sensing properties of the nanoemulsions were characterized in vitro and showed the unaltered spectral behavior of dyes after formulation. In rat 9L glioma cells loaded with nanoemulsion, the local pH of nanoemulsions was longitudinally quantified using optical microscopy and flow cytometry and displayed a steady decrease in pH to a level of 5.5 over 3 h, indicating rapid uptake of nanoemulsion to acidic compartments. Overall, these reagents enable real-time optical detection of intracellular pH in living cells in response to pharmacological manipulations. Moreover, recent approaches for in vivo cell tracking using magnetic resonance imaging (MRI) employ intracellular PFC nanoemulsion probes to track cells using (19)F MRI. However, the intracellular fate of these imaging probes is poorly understood. The pH-sensing nanoemulsions allow the study of the fate of the PFC tracer inside the labeled cell, which is important for understanding the PFC cell loading dynamics, nanoemulsion stability and cell viability over time.

Canagliflozin, an Inhibitor of the Na+-Coupled D-Glucose Cotransporter, SGLT2, Inhibits Astrocyte Swelling and Brain Swelling in Cerebral Ischemia.

Brain swelling is a major cause of death and disability in ischemic stroke. Drugs of the gliflozin class, which target the Na+-coupled D-glucose cotransporter, SGLT2, are approved for type 2 diabetes mellitus (T2DM) and may be beneficial in other conditions, but data in cerebral ischemia are limited. We studied murine models of cerebral ischemia with middle cerebral artery occlusion/reperfusion (MCAo/R). Slc5a2/SGLT2 mRNA and protein were upregulated de novo in astrocytes. Live cell imaging of brain slices from mice following MCAo/R showed that astrocytes responded to modest increases in D-glucose by increasing intracellular Na+ and cell volume (cytotoxic edema), both of which were inhibited by the SGLT2 inhibitor, canagliflozin. The effect of canagliflozin was studied in three mouse models of stroke: non-diabetic and T2DM mice with a moderate ischemic insult (MCAo/R, 1/24 h) and non-diabetic mice with a severe ischemic insult (MCAo/R, 2/24 h). Canagliflozin reduced infarct volumes in models with moderate but not severe ischemic insults. However, canagliflozin significantly reduced hemispheric swelling and improved neurological function in all models tested. The ability of canagliflozin to reduce brain swelling regardless of an effect on infarct size has important translational implications, especially in large ischemic strokes.

Cation flux through SUR1-TRPM4 and NCX1 in astrocyte endfeet induces water influx through AQP4 and brain swelling after ischemic stroke.

Brain swelling causes morbidity and mortality in various brain injuries and diseases but lacks effective treatments. Brain swelling is linked to the influx of water into perivascular astrocytes through channels called aquaporins. Water accumulation in astrocytes increases their volume, which contributes to brain swelling. Using a mouse model of severe ischemic stroke, we identified a potentially targetable mechanism that promoted the cell surface localization of aquaporin 4 (AQP4) in perivascular astrocytic endfeet, which completely ensheathe the brain's capillaries. Cerebral ischemia increased the abundance of the heteromeric cation channel SUR1-TRPM4 and of the Na+/Ca2+ exchanger NCX1 in the endfeet of perivascular astrocytes. The influx of Na+ through SUR1-TRPM4 induced Ca2+ transport into cells through NCX1 operating in reverse mode, thus raising the intra-endfoot concentration of Ca2+. This increase in Ca2+ stimulated calmodulin-dependent translocation of AQP4 to the plasma membrane and water influx, which led to cellular edema and brain swelling. Pharmacological inhibition or astrocyte-specific deletion of SUR1-TRPM4 or NCX1 reduced brain swelling and improved neurological function in mice to a similar extent as an AQP4 inhibitor and was independent of infarct size. Thus, channels in astrocyte endfeet could be targeted to reduce postischemic brain swelling in stroke patients.

Surgical Decompression of Traumatic Cervical Spinal Cord Injury: A Pilot Study Comparing Real-Time Intraoperative Ultrasound After Laminectomy With Postoperative MRI and CT Myelography.

BACKGROUND: Decompression of the injured spinal cord confers neuroprotection. Compared with timing of surgery, verification of surgical decompression is understudied. OBJECTIVE: To compare the judgment of cervical spinal cord decompression using real-time intraoperative ultrasound (IOUS) following laminectomy with postoperative MRI and CT myelography. METHODS: Fifty-one patients were retrospectively reviewed. Completeness of decompression was evaluated by real-time IOUS and compared with postoperative MRI (47 cases) and CT myelography (4 cases). RESULTS: Five cases (9.8%) underwent additional laminectomy after initial IOUS evaluation to yield a final judgment of adequate decompression using IOUS in all 51 cases (100%). Postoperative MRI/CT myelography showed adequate decompression in 43 cases (84.31%). Six cases had insufficient bony decompression, of which 3 (50%) had cerebrospinal fluid effacement at >1 level. Two cases had severe circumferential intradural swelling despite adequate bony decompression. Between groups with and without adequate decompression on postoperative MRI/CT myelography, there were significant differences for American Spinal Injury Association motor score, American Spinal Injury Association Impairment Scale grade, AO Spine injury morphology, and intramedullary lesion length (IMLL). Multivariate analysis using stepwise variable selection and logistic regression showed that preoperative IMLL was the most significant predictor of inadequate decompression on postoperative imaging (P = .024). CONCLUSION: Patients with severe clinical injury and large IMLL were more likely to have inadequate decompression on postoperative MRI/CT myelography. IOUS can serve as a supplement to postoperative MRI/CT myelography for the assessment of spinal cord decompression. However, further investigation, additional surgeon experience, and anticipation of prolonged swelling after surgery are required.

Initial Stress Hyperglycemia Is Associated With Malignant Cerebral Edema, Hemorrhage, and Poor Functional Outcome After Mechanical Thrombectomy.

BACKGROUND: Malignant cerebral edema (MCE) and intracranial hemorrhage (ICH) are associated with poor neurological outcomes despite revascularization after mechanical thrombectomy (MT). The factors associated with the development of MCE and ICH after MT are not well understood. OBJECTIVE: To determine periprocedural factors associated with MCE, ICH, and poor functional outcome. METHODS: We retrospectively analyzed anterior cerebral circulation large vessel occlusion cases that underwent MT from 2012 to 2019 at a single Comprehensive Stroke Center. Multivariate logistic regression analyses were performed to determine significant predictors of MCE, ICH, and poor functional outcome (modified Rankin Scale, 3-6) at 90 d. RESULTS: Four hundred patients were included. Significant independent predictors of MCE after MT included initial stress glucose ratio (iSGR) (odds ratio [OR], 14.26; 95% CI, 3.82-53.26; P < .001), National Institutes of Health Stroke Scale (NIHSS) (OR, 1.10; 95% CI, 1.03-1.18; P = .008), internal carotid artery compared with M1 or M2 occlusion, and absence of successful revascularization (OR, 0.16; 95% CI, 0.06-0.44; P < .001). Significant independent predictors of poor functional outcome included MCE (OR, 7.47; 95% CI, 2.20-25.37; P = .001), iSGR (OR, 5.15; 95% CI, 1.82-14.53; P = .002), ICH (OR, 4.77; 95% CI, 1.20-18.69; P = .024), NIHSS (OR, 1.10; 95% CI, 1.05-1.16; P < .001), age (OR, 1.04; 95% CI, 1.03-1.07; P < .001), and thrombolysis in cerebral infarction 2C/3 recanalization (OR, 0.12; 95% CI, 0.05-0.29; P < .001). CONCLUSION: Elevated iSGR significantly increases the risk of MCE and ICH and is an independent predictor of poor functional outcome. Thrombolysis in cerebral infarction 2C/3 revascularization is associated with reduced risk of MCE, ICH, and poor functional outcome. Whether stress hyperglycemia represents a modifiable risk factor is uncertain, and further investigation is warranted.

Comparative Therapeutic Effectiveness of Anticoagulation and Conservative Management in Traumatic Cerebral Venous Sinus Thrombosis.

BACKGROUND: Consensus is currently lacking in the optimal treatment for blunt traumatic cerebral venous sinus thrombosis (tCVST). Anticoagulation (AC) is used for treating spontaneous CVST, but its role in tCVST remains unclear. OBJECTIVE: To investigate the characteristics and outcomes of patients treated with AC compared with patients managed conservatively. METHODS: We retrospectively reviewed patients who presented to a Level 1 trauma center with acute skull fracture after blunt head trauma who underwent dedicated venous imaging. RESULTS: There were 137 of 424 patients (32.3%) presenting with skull fractures with tCVST on venous imaging. Among them, 82 (60%) were treated with AC while 55 (40%) were managed conservatively. Analysis of baseline characteristics demonstrated no significant difference in age, sex, admission Glasgow Coma Scale, admission Injury Severity Score, rates of associated intracranial hemorrhage, or neurosurgical interventions. New or worsening intracranial hemorrhage was seen in 7 patients treated with AC. Patients on AC had significantly lower mortality than non-AC (1% vs 15%; P = .003). There was no difference in the Glasgow Coma Scale or Glasgow Outcome Scale at last clinical follow-up. On follow-up venous imaging, patients treated with AC were more likely to experience full thrombus recanalization than non-AC (54% vs 32%; P = .012), and subsequent multiple regression analysis revealed that treatment with AC was a significant predictor of full thrombus recanalization (odds ratio, 5.18; CI, 1.60-16.81; P = .006). CONCLUSION: Treatment with AC for tCVST due to blunt head trauma may promote higher rates of complete thrombus recanalization when compared with conservative management.

Proposal of a Management Algorithm to Predict the Need for Expansion Duraplasty in American Spinal Injury Association Impairment Scale Grades A-C Traumatic Cervical Spinal Cord Injury Patients.

Expansion duraplasty to reopen effaced subarachnoid space and improve spinal cord perfusion, autoregulation, and spinal pressure reactivity index (sPRX) has been advocated in patients with traumatic cervical spinal cord injury (tCSCI). We designed this study to identify candidates for expansion duraplasty, based on the absence of cerebrospinal fluid (CSF) interface around the spinal cord on magnetic resonance imaging (MRI), in the setting of otherwise adequate bony decompression. Over a 61-month period, 104 consecutive American Spinal Injury Association Impairment Scale (AIS) grades A-C patients with tCSCI had post-operative MRI to assess the adequacy of surgical decompression. Their mean age was 53.4 years, and 89% were male. Sixty-one patients had falls, 31 motor vehicle collisions, 11 sport injuries, and one an assault. The AIS grade was A in 56, B in 18, and C in 30 patients. Fifty-four patients had fracture dislocations; there was no evidence of skeletal injury in 50 patients. Mean intramedullary lesion length (IMLL) was 46.9 (standard deviation = 19.4) mm. Median time from injury to decompression was 17 h (interquartile range 15.2 h). After surgery, 94 patients had adequate decompression as judged by the presence of CSF anterior and posterior to the spinal cord, whereas 10 patients had effacement of the subarachnoid space at the injury epicenter. In two patients whose decompression was not definitive and post-operative MRI indicated inadequate decompression, expansion duraplasty was performed. Candidates for expansion duraplasty (i.e., those with inadequate decompression) were significantly younger (p < 0.0001), were AIS grade A (p < 0.0016), had either sport injuries (six patients) or motor vehicle collisions (three patients) (p < 0.0001), had fracture dislocation (p = 0.00016), and had longer IMLL (p = 0.0097). In regression models, patients with sport injuries and inadequate decompression were suitable candidates for expansion duraplasty (p = 0.03). Further, 9.6% of patients failed bony decompression alone and either did (2) or would have (8) benefited from expansion duraplasty.