Evaluating Changes in Pulsatile Flow With Endovascular Stents in an In Vitro Blood Vessel Model: Potential Implications for the Future Management of Neurovascular Compression Syndromes.

BACKGROUND: Neurovascular compression syndromes (NVCS), encompassing conditions such as trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia, significantly impair patient quality of life through abnormal vascular compression and micro-pulsation of vasculature on cranial nerves at the Obersteiner-Redlich zone. The modulation of pulsatile flow dynamics via endovascular stents presents a novel research frontier for alleviating these syndromes. AIM: The primary aim of this investigation was to delineate the impact of various endovascular stents on pulsatile flow within an in vitro model of a blood vessel, thereby elucidating their potential applicability in the therapeutic management of NVCS. MATERIALS AND METHODS: A simple in vitro analog of a posterior circulation artery was developed, employing an intravenous pump to replicate cardiac-induced blood flow. Within this model, alterations in pulsatile flow were quantitatively assessed following the introduction of three categorically distinct endovascular stents, varying in size. This assessment was facilitated through the employment of both micro-Doppler and Doppler ultrasound methodologies. RESULTS: The Pipeline 5x35 mm stent (Medtronic, Minneapolis, MN) demonstrated the most significant reductions in peak systolic velocity (Vmax) and pulsatility index (PI), PI especially over the stent, suggesting its potential for drastically altering blood flow dynamics. Similarly, Neuroform Atlas 4.5x30 mm and Neuroform Atlas 4x24 mm stents (Stryker, Kalamazoo, MI) also showed notable decreases in hemodynamic parameters, albeit to different extents. Statistical analysis confirmed that these changes were significantly different from the control (P < 0.0001 for PI and Vmax; P < 0.05 for inter-stent comparisons), except for proximal PI means, which did not significantly differ from the control (P = 0.2777). CONCLUSION: These findings affirm the potential of endovascular stents to substantially modulate arterial pulsatility. The observed decrease in pulsatile flow resultant from endovascular stent application has the potential to attenuate ectopic nerve excitation, a hallmark of NVCS. Consequently, this research highlights the prospective utility of endovascular stents in developing minimally invasive therapeutic approaches for NVCS.

Radiographic Predictors of Shunt Dependency in Intracranial Hemorrhage With Intraventricular Extension.

Background Intracranial hemorrhage (ICH) may be complicated by intraventricular hemorrhage (IVH) and hydrocephalus, which can require the placement of a ventriculoperitoneal shunt (VPS). ICH and IVH risk scores using radiographic and clinical characteristics have been developed but utilization for assessment of future need for VPS placement is limited. Methods This is a single-institution retrospective review for patients with primary ICH with IVH from 2018-2020. Initial CTs and charts were analyzed to determine ICH, IVH, LeRoux and Graeb scores, Evans' index, ICH and IVH volumes, and comorbidities. Outcomes including Glasgow coma scale (GCS), National Institute of Health Stroke Scale (NIHSS), length of stay, and shunt placement were evaluated with bivariate correlations, t-tests, chi-squared tests, and receiver operating characteristic (ROC) curves (p=0.05). Results A total of 130 patients were included of which 102 underwent full treatment beyond hospital day one. VPS placement was significantly associated with longer length of stay (p<0.001), discharge NIHSS (p=0.001), arrival Evans' index (p<0.001), IVH (p=0.033), LeRoux (p=0.049), but not comorbidities, ICH score, or admission GCS. When treated beyond hospital day one, Evans' index (p<0.001), IVH volume (p=0.029), Graeb (p=0.0029), IVH (p=0.004), Slice (p=0.015), and Leroux scores (p=0.006) were associated with shunt placement of which an Evans' index of 0.31 or greater had highest sensitivity and specificity (area under the ROC curve (AUC) 0.81, sensitivity 81%, specificity 0.76). Conclusions The higher the Evans' index, Graeb, IVH, Slice, and LeRoux scores on admission, the higher the risk of shunt dependency in patients undergoing full treatment beyond hospital day one. Admission imaging scores significantly predict the development of shunt dependence and may be considered in treatment.

Intraoperative localization and "snowman" muscle pledget repair for ventral dural defect in a case of spontaneous intracranial hypotension.

BACKGROUND: This image report with technical notes is the first to illustrate and describe the technique used to treat spinal cerebrospinal fluid (CSF) leaks with the "snowman" muscle pledget. A 49-year-old male presented with orthostatic headaches as well as the left abducens nerve palsy. Patient's workup including findings of diffuse meningeal enhancement on magnetic resonance imaging, lumbar puncture opening pressure of 4 cm H2O, and CT myelogram demonstrating evidence of ventral spinal thoracic CSF leak. CASE DESCRIPTION: Procedure took place in a hybrid biplane operating room so that simultaneous digital subtraction myelogram may also be performed for intraoperative localization. Dural defect was identified intraoperatively and repaired with thoracic laminectomy and "snowman" muscle pledget technique. Postoperatively, the patient did well with resolution of his symptoms. CONCLUSION: The authors have proposed a grading scale to aid in the work up and management of intracranial hypotension. The use of a hybrid biplane operating room and "snowman" muscle pledget technique is a safe and effective technique to treat spontaneous spinal CSF leaks resulting from dural defects.

Retraction: Effects of the COVID-19 Pandemic on Stroke Patients.

[This retracts the article DOI: 10.7759/cureus.9995.].

Spinal Arteriovenous Malformation: Case Report and Review of the Literature.

Spinal arteriovenous malformations (AVMs) are a rare form of spinal blood vessel defect that results in vessel engorgement leading to clinical signs secondary to mass effect and ischemia. We present the patient's clinical course following suspicion of spinal AVM along with a review of current classification and imaging modalities.

Contrast Extravasation Post Thrombectomy in Patients With Acute Cerebral Stroke: A Review and Recommendations for Future Studies.

Mechanical thrombectomy (MT) for cerebral revascularization in acute stroke is now considered standard of care in select patients. Patients are assessed routinely after MT with CT scanning. The phenomenon of contrast staining is well documented in the literature and is posited to be related to increased blood-brain barrier (BBB) permeability of susceptible and/or infarcting brain tissue allowing angiographic contrast to be visualized outside the normal cerebral vasculature. In some cases, this can progress to include frank blood/contrast extravasation or even more seriously lead to intraparenchymal hemorrhage (IPH) with less favorable clinical outcomes. The relationship of this staining phenomenon and how it may have a cause or effect relationship with progression to hemorrhage is unclear. Many studies have been performed trying to better characterize this radiographic finding in terms of accurate diagnosis and potential for influencing prognosis. A literature review included a glaring lack of standardization in the application of terminology and quantitative/qualitative analysis. Dual energy CT (DECT) appears to be the best imaging modality to differentiate blood from contrast, but its application is limited since it is not as available as conventional CT. The possibility that risk factors are associated with progression of mixed density (blood and contrast) extravasations to frank IPH with resultant poorer outcomes is suggested in some studies. Overall, there remains a lack of consensus on how to best interpret this radiographic finding in altering any future stroke treatment(s). Recommendations of how to overcome this are postulated by the authors, which include standardization of terminology, progression toward more DECT use.

Effects of the COVID-19 Pandemic on Stroke Patients.

Introduction The severe acute respiratory syndrome coronavirus 2 (SARS2-CoV-2) induced pandemic (COVID-19 pandemic) has affected healthcare in all aspects, including stroke care. We sought to investigate this effect with analysis of our hospital's stroke treatment protocols as well as stroke volume on state, regional, and national levels. Methods This was a retrospective review of prospectively collected data from our stroke registry to assess the impact of the SARS2-CoV-2 induced pandemic on the volume of stroke patients presenting to our facility. Demographics collected included age, sex, race, National Institute of Health Stroke Scale (NIHSS) on admission, discharge modified Rankin Score (mRS), type of stroke (ischemic, hemorrhagic, or transient ischemic attack), time of symptom onset, and time to initial imaging. Data were also stratified by date and comparison was made between the intra-COVID-period (March and April 2020), pre-COVID period (March and April 2019), and peri-COVID period (January and February 2020). To determine stroke trends on a national level, we utilized the Get with the Guidelines (GWTG) stroke database to compare stroke volumes in the pre-COVID, peri-COVID, and intra-COVID periods between our hospital, all California hospitals, and the West and Pacific regions. Results There was a significant increase in last known well time (LKWT) to arrival to the emergency department (ED) (LKWT to door) as well as time from arrival to the ED to obtaining a computed tomography (CT) of the head (door to CT) in March 2020 compared to 2019 (p=0.0220 and p=0.0475, respectively). There were significantly fewer transient ischemic attacks (TIAs) in California hospitals as well as in March and April 2020 in comparison to January and February 2020 (p=0.0417). Similarly, there were significantly fewer TIAs in March and April 2019 compared to March and April 2020 (p=0.0360). The decrease in TIAs was also seen at our hospital in both time frame comparisons as well as in West Regional Hospitals in March and April 2020 compared to March and April 2019 (p=0.0111, p=0.0215, and p=0.0414, respectively). Conclusion Stroke care has been disrupted by the COVID-19 pandemic worldwide. We identified a delay in LKWT to door as well as time from door to CT in March 2020 compared to March 2019 at our institution. There was a statistically significant decrease in final diagnosis of TIA at our hospital, all California hospitals, and all West Regional hospitals during the March-April 2020 window, suggesting that some patients with minor stroke symptoms may not be presenting to the hospital in the midst of the pandemic. Strategies to minimize delays in care and maximize functional recovery must continue to evolve as new challenges are met during the COVID-19 pandemic.

A Novel Method for Practicing Fascial Closure with Suture.

Closure of the fascial layer can be challenging to learn for junior level residents. Wound dehiscence involving the fascial layer can lead to complicated clinical courses for patients, including readmission to the hospital, wound vacuum placement, antibiotic regimens, and re-operation. Typical suturing techniques taught in medical school focus more on basic techniques of suture placement such as interrupted or running techniques. The aim of this study is to introduce a method of practicing fascial closure using easily obtainable items. Though there is no substitute for placement of suture and closure of fascia in vivo, this method allows one to practice the motor repetition of fascial suture placement and provides one with the ability to check their work.

Use of Endovascular Simulator in Training of Neurosurgery Residents - A Review and Single Institution Experience.

Simulators for surgical procedures and interventions have undergone significant technological advancement in the past decade and are becoming more commonplace in medical training. Neurosurgery residents across multiple training levels underwent performance evaluation using a neuro-interventional simulator, employing a variety of metrics for assessment. We identified seven core metrics used in the evaluation of neurosurgery residents performing simulated mechanical thrombectomies. Additionally, a systematic PubMed search for studies related to Neurointerventional Radiology training via simulation was performed. The purpose of this study is to examine the validity and benefits of training with these simulation devices and compare our institution's experience. Additionally, an exploration of their applicability to neurosurgery resident training is discussed.

Differential Expression of Vascular Endothelial Growth Factor-A165 Isoforms Between Intracranial Atherosclerosis and Moyamoya Disease.

BACKGROUND: Vascular endothelial growth factor-A165 (VEGF-A165) has been identified as a combination of 2 alternative splice variants: proangiogenic VEGF-A165a and antiangiogenic VEGF-A165b. Intracranial atherosclerotic disease (ICAD) and moyamoya disease (MMD) are 2 main types of intracranial arterial steno-occlusive disorders with distinct capacities for collateral formation. Recent studies indicate that VEGF-A165 regulates collateral growth in ischemia. Therefore, we investigated if there is a distinctive composition of VEGF-A165 isoforms in ICAD and MMD. METHODS: Sixty-six ICAD patients, 6 MMD patients, and 5 controls were enrolled in this prospective study. ICAD and MMD patients received intensive medical management upon enrollment. Surgery was offered to 9 ICAD patients who had recurrent ischemic events, 6 MMD patients, and 5 surgical controls without ICAD. VEGF-A165a and VEGF-A165b plasma levels were measured at baseline, within 1 week after patients having surgery, and at 1, 3, and 6 months after treatment. RESULTS: A significantly higher baseline VEGF-A165a/b ratio was observed in MMD compared to ICAD (P = .016). The VEGF-A165a/b ratio increased significantly and rapidly after surgical treatment in ICAD (P = .026) more so than in MMD and surgical controls. In patients with ICAD receiving intensive medical management, there was also an elevation of the VEGF-A165a/b ratio, but at a slower rate, reaching the peak at 3 months after initiation of treatment (baseline versus 3 months VEGF-A165a/b ratio, P = .028). CONCLUSIONS: Our study shows an increased VEGF-A165a/b ratio in MMD compared to ICAD, and suggests that both intensive medical management and surgical revascularization elevate the VEGF-A165a/b ratio in ICAD patients.

Effect of insurance and racial disparities on outcomes in traumatic brain injury.

INTRODUCTION: We evaluated outcome and resource utilization disparities between commercially insured, Medicaid, and Medicare patients. We further analyzed racial disparities in a subset cohort. METHODS: We reviewed the MarketScan database (2000-2009) for adult traumatic brain injury (TBI) patients. Analyses were performed to evaluate outcome differences by insurance type and race. Outpatient service utilization disparities by insurance and race were also evaluated. RESULTS: Our study included 92,159 TBI patients, 44,108 (47.9%) of whom utilized commercial insurance, 19,743 (21.4%) utilized Medicaid, and 28,308 (30.7%) utilized Medicare. In-hospital mortality was lowest for commercially insured (5.0%) versus 7.6% and 8.5% for Medicaid and Medicare patients, respectively (p < 0.0001). Medicaid patients had a longer hospitalization than commercially insured (12 days versus 6 days; p < 0.0001). Medicaid patients were 1.29 and 1.78 times more likely to die and experience complications than the commercially insured. Females had a lower mortality risk (odds ratio [OR]: 0.80, p < 0.0001) and less complications (OR: 0.67; p < 0.0001) than males. Higher comorbidities increased mortality risk (OR: 2.71; p < 0.0001) and complications (OR: 2.96, p < 0.0001). Mild injury patients had lower mortality (OR: 0.01; p < 0.0001) and less complications (OR: 0.07; p < 0.0001). Medicare (OR: 1.33; p < 0.0001) and higher comorbidity (OR: 1.26; p < 0.0001) patients utilized outpatient rehabilitation services more frequently. Medicare patients had twice the emergency department visits as the commercially insured (p < 0.0001). Medicare (16.6%) patients utilized more rehabilitation than commercially insured (13.4%) and Medicaid (9.1%) patients. Racial disparities were analyzed in a subset of 12,847 white and 4,780 African American (AA) patients. Multivariate analysis showed that AAs were more likely to experience a complication than white patients (OR: 1.13; p = 0.0024) and less likely to utilize outpatient rehabilitation services (OR: 0.83; p = 0.0025) than whites. CONCLUSIONS: Insurance and racial disparities continue to exist for TBI patients. Insurance status appears to have an impact on short- and long-term outcomes to a greater degree than patient race.

How can a chemical element elicit complex immunopathology? Lessons from mercury-induced autoimmunity.

Although most autoimmune diseases develop without a manifest cause, epidemiological studies indicate that external factors play an important role in triggering or aggravating autoimmune processes in genetically predisposed individuals. Nevertheless, most autoimmune disease-promoting environmental agents are unknown because their relationships to immune function are not understood. Thus, the study of animal models of chemically-induced autoimmunity should shed light on the pathways involved and allow us to identify these agents. The rodent model of heavy metal-induced autoimmunity is one of the most intriguing experimental systems available to address such questions. Although the ultimate pathophysiology of this model remains mysterious, recent studies have started to elucidate the mechanisms by which heavy metal exposure leads to immune activation and loss of self-tolerance.

Interindividual variability and parent of origin DNA methylation differences at specific human Alu elements.

We investigated the CpG methylation of 19 specific members of Alu sub-families in human DNA isolated from whole blood, using an assay based on methylation-sensitive restriction endonuclease digestion of genomic DNA and 'hot-stop' polymerase chain reaction. We found significant interindividual variability in the level of methylation for specific Alu elements among the members of 48 three-generation families. Surprisingly, some of the elements also displayed quantitative parent of origin methylation differences; i.e. the mean level of methylation differed significantly when the insertions were transmitted through paternal versus maternal meiosis. Bisulfite sequence analysis of individual elements at such loci suggests, further, that maternal and paternal elements differ in the propensity of particular CpG sites to become unmethylated. Some individuals who exhibited high levels of methylation at specific Alu elements came from families in which more than one member also exhibited abnormal patterns of methylation at the differentially methylated regions of the IGF2/H19 or IGF2R loci, suggesting that there may be heritable differences between individuals in the fidelity with which allelic DNA methylation differences are established or maintained. Quantitative parental origin differences in methylation were identified only for Alu elements that lie in sub-telomeric or sub-centromeric bands of human chromosomes, whereas those assayed at intermediate positions did not exhibit any significant differences. The centromere/telomere restricted location of the methylation differences and the fact that none of these differences occur in regions of chromosomes known to contain transcriptionally imprinted genes suggest that maternal/paternal epigenetic modifications may play additional roles in processes other than transcriptional control.