Occipital venous sinus stenting for idiopathic intracranial hypertension and pulsatile tinnitus: A case series.

Venous sinus stenting for dural venous sinus outflow obstruction due to an intrinsic filling obstruction or extrinsic stenosis is an increasingly popular treatment strategy for idiopathic intracranial hypertension (IIH) and isolated pulsatile tinnitus (PT). The most common site of stenosis is the lateral venous sinus at the transverse-sigmoid junction. Approximately 10% of the population has a persistent occipital venous sinus (OVS), a variant that may be the dominant venous drainage pathway in the setting of a hypoplastic or aplastic transverse sinus. OVS stenosis has been rarely associated with IIH and isolated PT with only a handful published cases. We herein report a retrospective series of OVS stenting in five patients, four of whom presented with non-IIH PT and one with IIH.

CGRP as a potential mediator for the sexually dimorphic responses to traumatic brain injury.

BACKGROUND: The outcomes of traumatic brain injury (TBI) exhibit variance contingent upon biological sex. Although female sex hormones exert neuroprotective effects, the administration of estrogen and progesterone has not yielded conclusive results. Hence, it is conceivable that additional mediators, distinct from female sex hormones, merit consideration due to their potential differential impact on TBI outcomes. Calcitonin gene-related peptide (CGRP) exhibits sexually dimorphic expression and demonstrates neuroprotective effects in acute brain injuries. In this study, we aimed to examine sex-based variations in TBI structural and functional outcomes with respect to CGRP expression. METHODS: Male and female Sprague Dawley rats were exposed to controlled cortical impact to induce severe TBI, followed by interventions with and without CGRP inhibition. In the acute phase of TBI, the study centered on elucidating the influence of CGRP on oxidative stress, nuclear factor erythroid 2-related factor 2 (Nrf2) and endothelial nitric oxide synthase (eNOS) signaling in the peri-impact tissue. Subsequently, during the chronic phase of TBI, the investigation expanded to evaluate CGRP expression in relation to lesion volume, microvascular dysfunction, and white matter injury, as well as working and spatial memory, anxiety-like, and depression-like behaviors in subjects of both sexes. RESULTS: Female rats exhibited elevated levels of CGRP in the peri-impact brain tissue during both baseline conditions and in the acute and chronic phases of TBI, in comparison to age-matched male counterparts. Enhanced CGRP levels in specific brain sub-regions among female rats correlated with superior structural and functional outcomes following TBI compared to their male counterparts. CGRP inhibition induced heightened oxidative stress and a reduction in the expression of Nrf2 and eNOS in both male and female rats, with the observed alteration being more pronounced in females than in males. CONCLUSIONS: This study marks the inaugural identification of CGRP as a downstream mediator contributing to the sexually dimorphic response observed in TBI outcomes.

Investigating sex disparities in traumatic brain injury (TBI) is crucial for the advancement of precision therapeutics. Despite the neuroprotective effects demonstrated by female sex hormones, the administration of estrogen and progesterone has not produced conclusive results. Therefore, it is conceivable that additional mediators, separate from female sex hormones, warrant consideration due to their potential differential influence on TBI outcomes. In this study, we examined sex-related variations in calcitonin gene-related peptide (CGRP) expression in peri-impact brain tissue and investigated its potential implications on associated TBI outcomes. CGRP exhibits sexually dimorphic expression and exerts a multifaceted influence on diverse physiological processes that contribute to the pathophysiology of TBI. Our findings reveal that female rats exhibit heightened CGRP levels at both baseline and post-TBI within specific brain sub-regions, thereby contributing to superior structural and functional outcomes compared to their age-matched male counterparts. Additionally, we identified substantial sex-based variations in mechanisms modulated by CGRP pertaining to oxidative stress and microvascular dysfunction. The disparities in CGRP levels may be crucial for comprehending the advantageous outcomes noted in female TBI. Therefore, elucidating the sex-related distinctions in CGRP within TBI brains could pave the way for improved management and treatment strategies for TBI in both male and female individuals.

Impact of Cerebral Revascularization on Pial Collateral Flow in Patients With Unilateral Moyamoya Disease Using Quantitative Magnetic Resonance Angiography.

BACKGROUND AND OBJECTIVES: Moyamoya disease (MMD) is a chronic steno-occlusive disease of the intracranial circulation that depends on neoangiogenesis of collateral vessels to maintain cerebral perfusion and is primarily managed with cerebral revascularization surgery. A quantitative assessment of preoperative and postoperative collateral flow using quantitative magnetic resonance angiography with noninvasive optimal vessel analysis (NOVA) was used to illustrate the impact of revascularization on cerebral flow distribution. METHODS: A retrospective review of patients with unilateral MMD who underwent direct, indirect, or combined direct/indirect cerebral revascularization surgery was conducted between 2011 and 2020. Using NOVA, flow was measured at the anterior cerebral artery (ACA), ACA distal to the anterior communicating artery (A2), middle cerebral artery (MCA), posterior cerebral artery (PCA), and PCA distal to the posterior communicating artery (P2). Pial flow (A2 + P2) and collateral flow (ipsilateral [A2 + P2])-(contralateral [A2 + P2]) were measured and compared before and after revascularization surgery. Total hemispheric flow (MCA + A2 + P2) with the addition of the bypass graft flow postoperatively was likewise measured. RESULTS: Thirty-four patients with unilateral MMD underwent cerebral revascularization. Median collateral flow significantly decreased from 68 to 39.5 mL/min (P = .007) after bypass. Hemispheres with maintained measurable bypass signal on postoperative NOVA demonstrated significant reduction in median collateral flow after bypass (P = .002). Median total hemispheric flow significantly increased from 227 mL/min to 247 mL/min (P = .007) after bypass. Only one patient suffered an ipsilateral ischemic stroke, and no patients suffered a hemorrhage during follow-up. CONCLUSION: NOVA measurements demonstrate a reduction in pial collateral flow and an increase in total hemispheric flow after bypass for MMD, likely representing a decrease in leptomeningeal collateral stress on the distal ACA and PCA territories. Further studies with these measures in larger cohorts may elucidate a role for NOVA in predicting the risk of ischemic and hemorrhagic events in MMD.

Intrinsic diving reflex induces potent antioxidative response by activation of NRF2 signaling.

Aims: This study aims to elucidate the underlying mechanisms of diving reflex, a powerful endogenous mechanism supporting underwater mammalian survival. Antioxidative responses, observed in marine mammals, may be contributing factors. Using a multi-organ approach, this study assesses whether acute and chronic diving reflex activate nuclear factor-erythroid-2-related factor 2 (NRF2) signaling pathways, which regulate cellular antioxidant responses. Methods: Male Sprague-Dawley rats ( n =38) underwent either a single diving session to elicit acute diving reflex, or daily diving sessions for 4-weeks to produce chronic diving reflex. NRF2 (total, nuclear, phosphorylated), NRF2-downstream genes, and malondialdehyde were assessed via Western blot, immunofluorescence, RT-PCR, and ELISA in brain, lung, kidney, and serum. Results: Diving reflex increased nuclear NRF2, phosphorylated NRF2, and antioxidative gene expression, in an organ-specific and exposure time-specific manner. Comparing organs, the brain had the highest increase of phosphorylated NRF2 expression, while kidney had the highest degree of nuclear NRF2 expression. Comparing acute and chronic sessions, phosphorylated NRF2 increased the most with chronic diving reflex, but acute diving reflex had the highest antioxidative gene expression. Notably, calcitonin gene-related peptide appears to mediate diving reflex' effects on NRF2 activation. Conclusions: Acute and chronic diving reflex activate potent NRF2 signaling in the brain and peripheral organs. Interestingly, acute diving reflex induces higher expression of downstream antioxidative genes compared to chronic diving reflex. This result contradicts previous assumptions requiring chronic exposure to diving for induction of antioxidative effects and implies that the diving reflex has a strong translational potential during preconditioning and postconditioning therapies. Key Points: Diving reflex activates potent NRF2 signaling via multiple mechanisms, including phosphorylation, nuclear translocation, and KEAP1 downregulation with both acute and chronic exposure.Diving reflex activates NRF2 via differential pathways in the brain and other organs; phosphorylated NRF2 increases more in the brain, while nuclear NRF2 increases more in the peripheral organs.Acute diving reflex exposure induces a more pronounced antioxidative effect than chronic diving reflex exposure, indicating that the antioxidative response activated by diving reflex is not dependent upon chronic adaptive responses and supports diving reflex as both a preconditioning and postconditioning treatment.

Flow diverter surface modifications for aneurysm treatment: A review of the mechanisms and data behind existing technologies.

Flow diversion (FD) has become a mainstay treatment for large wide-necked aneurysms. Despite excellent safety and efficacy, the risk of thromboembolic complications necessitates the use of dual antiplatelet therapy (DAPT). The use of DAPT makes hemorrhagic complications of stenting carry high morbidity and mortality. Additionally, DAPT usage carries a risk of "nuisance" complications that do not directly impact intracranial circulation but need to be managed nonetheless. To circumvent this issue, the most recent generation of flow diverters have undergone surface modification with various compounds to confer blood compatibility to limit clotting and thrombosis. While these newer generation flow diverters are marketed to enhance ease of deployment, the goal is to eventually facilitate single antiplatelet use with flow diverter treatment. This generation of FDs have potential to expand indications beyond unruptured wide-necked aneurysms to include ruptured intracranial aneurysms without the necessity of DAPT. Currently, no comprehensive review details the molecular mechanisms and pre-clinical and clinical data on these modifications. We seek to fill this gap in the literature by consolidating information on the coating technology for four major FDs currently in clinical use-PipelineTM Flex and Vantage Shield TechnologyTM, FREDTMX, p48/64 hydrophilic coating, and Acandis Dervio® 2heal-to serve as a reference guide in neurointerventional aneurysm treatment. Although the Balt silkTM was one of the first FDs, it is uncoated, thus we will not cover this device in our review. A literature review was performed to obtain information on each coating technology for the major flow diverters currently on the market using international databases (PUBMED, Embase, Medline, Google Scholar). The search criteria used the keywords for each coating technology of interest "phosphorylcholine," "poly 2-methoxyethyl acrylate," "hydrophilic polymer coating," and "fibrin-heparin" Keywords related to the device names "Pipeline Shield," "Pipeline Shield with Flex Technology," "FRED," "FREDX," "p64," "p64-HPC," "Derivo 2heal" were also used. Studies that detailed the mechanism of action of the coating, any pre-clinical studies with surface-modified intravascular devices, and any clinical retrospective series, prospective series, or randomized clinical trials with surface-modified devices for aneurysm treatment were included.

Long-term outcomes of surgical clipping of saccular middle cerebral artery aneurysms: a consecutive series of 92 patients.

Despite advances in endovascular treatment, microsurgical clipping of middle cerebral artery (MCA) aneurysms remains appropriate. We review the high occlusion rate and treatment durability seen with surgical clipping of MCA aneurysms. We retrospectively reviewed patients who underwent microsurgical clipping of saccular MCA aneurysms by a single surgeon. Outcomes included aneurysm occlusion rate and durability, modified Rankin scale (mRS), and postoperative neurological morbidities. Ninety-two patients with 92 saccular MCA aneurysms were included, 50% of which were ruptured aneurysms. The mean follow-up period was 59 months. Complete aneurysm occlusion was achieved in all except one patient (99%) with near-complete occlusion. MCA aneurysm clipping was durable, with only one patient (1%) requiring retreatment after 4 years due to regrowth. Of the cohort, 79.3% achieved mRS 0-2 at last follow-up, including all with unruptured aneurysms. Poor outcome at discharge was associated with age > 65 (p = .03), postoperative neurological morbidities (p = .006), and aneurysm rupture (p < .001). Older age remained the single correlate for poor long-term outcome (p = .04). For ruptured aneurysms, predictors of poor long-term outcome included hemiparesis on presentation (p = .017), clinical vasospasm requiring treatment (p = .026), and infarction related to vasospasm (p = .041). Older age (p = .046) and complex anatomy (p = .036) were predictors of new postoperative neurological morbidities in the unruptured group. MCA aneurysm clipping is safe, durable, and should be considered first-line treatment for patients with saccular MCA aneurysms, especially in centers with abundant surgical experience.

Hemodynamic outcomes of stenting for vertebrobasilar insufficiency in patients with a low flow state.

INTRODUCTION: The Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS) study determined patients with low flow in their vertebrobasilar (VB) system are at increased risk of recurrent stroke. Endovascular interventions such as angioplasty and stenting are reserved for patients with refractory symptoms; however, few series to date have demonstrated either hemodynamic or clinical outcomes in this high-risk patient group. We present our combined institutional series of patients with symptomatic VB atherosclerotic disease and low-flow state who underwent angioplasty and stenting. METHODS: Retrospective chart review of patients undergoing angioplasty and stenting for symptomatic VB atherosclerotic disease at two institutions was performed. Clinical and radiographical outcomes were collected including flow rates using quantitative MRA (QMRA) pre- and post-stenting. RESULTS: Seventeen patients underwent angioplasty and stenting for symptomatic VB atherosclerotic disease and met VERiTAS low-flow state criteria. There were four cases (23.5%) of periprocedural stroke, two of which were minor and transient. The stent was placed intracranially in 82.4% of patients. Basilar and bilateral posterior cerebral artery (PCA) flows significantly improved post-stenting (p < 0.05) and normalized based upon VERiTAS criteria in all patients. Fourteen patients had delayed QMRA at mean follow-up 20 months demonstrating appropriate patency and flow post-stenting. Two patients (10%) had recurrent stroke, one from medication nonadherence and in-stent thrombosis, and the other from a procedural dissection that subsequently became symptomatic. CONCLUSIONS: Our series demonstrates angioplasty and stenting significantly improve intracranial flow over long-term. Angioplasty and stenting may improve the natural history of low-flow VB atherosclerotic disease.

A comparison of endovascular coil systems for the treatment of small intracranial aneurysms.

BACKGROUND: Endovascular coiling of small, intracranial aneurysms remains controversial and difficult, despite advances in technology. METHODS: We retrospectively reviewed data for 62 small aneurysms (<3.99 mm) in 59 patients. Occlusion rates, complications rates, and coil packing densities were compared between subgroups based upon coil type and rupture status. RESULTS: Ruptured aneurysms predominated (67.7%). Aneurysms measured 2.99 ± 0.63 mm by 2.51 ± 0.61 mm with an aspect ratio of 1.21 ± 0.34 mm. Brands included Optima (Balt) (29%), MicroVention Hydrogel (24.2%), and Penumbra SMART (19.4%) coil systems. Average packing density was 34.3 ± 13.5 mm3. Occlusion rate was 100% in unruptured aneurysms; 84% utilized adjuvant devices. For ruptured aneurysms, complete occlusion or stable neck remnant was achieved in 88.6% while recanalization occurred in 11.4%. No rebleeding occurred. Average packing density (p = 0.919) and coil type (p = 0.056) did not impact occlusion. Aspect ratio was smaller in aneurysms with technical complications (p = 0.281), and aneurysm volume was significantly smaller in those with coil protrusion (p = 0.018). Complication rates did not differ between ruptured and unruptured aneurysms (22.6 vs. 15.8%, p = 0.308) or coil types (p = 0.830). CONCLUSION: Despite advances in embolization devices, coiling of small intracranial aneurysms is still scrutinized. High occlusion rates are achievable, especially in unruptured aneurysms, with coil type and packing density suggesting association with complete occlusion. Technical complications may be influenced by aneurysm geometry. Advances in endovascular technologies have revolutionized small aneurysm treatment, with this series demonstrating excellent aneurysm occlusion especially in unruptured aneurysms.

Hyperperfusion syndrome after superficial temporal artery-middle cerebral artery bypass for non-moyamoya steno-occlusive disease.

BACKGROUND AND OBJECTIVES: Stroke is a major cause of morbidity and mortality worldwide, and intracranial stenoses increase the risk for stroke. Superficial temporal artery to middle cerebral artery bypass can be beneficial in selected patients with non-moyamoya steno-occlusive disease, however data is limited regarding the postoperative occurrence of hyperperfusion syndrome in this population. This case series describes the outcomes and complications, including hyperperfusion, in these patients who underwent bypass. METHODS: This is a retrospective review of bypass procedures done for medically refractory intracranial stenosis at a single institution by a single surgeon between 2014 and 2021. RESULTS: 30 patients underwent 33 bypass procedures for unequivocal non-moyamoya steno-occlusive disease. All patients had immediate bypass patency on post-operative day one. Major perioperative complications (9%) included one stroke and two cases of hyperperfusion syndrome. Minor perioperative complications (12%) included two seizures, one superficial wound infection and one deep vein thrombosis. Modified Rankin Score improved in 20 patients (74%), worsened in one patient (4%), and remained stable in seven patients (22%) at the last follow up. Twenty-three patients (85%) had scores ≤ 2. The recurrent stroke rate was 3% at 30 days and 7% at two years. The bypass patency rate at one year was 87.5%. CONCLUSION: In this series, bypass for patients with medically refractory non-moyamoya steno-occlusive disease was well tolerated and effective, with overall favorable outcomes. The occurrence of hyperperfusion syndrome is rare but significant and should be considered in post-operative management of this population.

FLAIR hyperintense vessels on MRI post brain arteriovenous malformation embolization: A novel finding associated with post-procedure intraparenchymal hemorrhage.

INTRODUCTION: Brain arteriovenous malformations (BAVMs) are frequently managed by endovascular embolization with a growing number of centers embolizing with intent to cure. Hemorrhage post-embolization is a severe and poorly understood complication. We present a novel imaging finding associated with post-embolization hemorrhage that has significantly impacted the management of patients at our institution. METHODS: A retrospective review of all patients undergoing embolization of BAVM at a single center was performed. Post-embolization magnetic resonance imaging (MRI) was reviewed for the presence of T2 fluid-attenuated inversion recovery (FLAIR) hyperintense vessels (FHVs). Bivariate analysis was performed to determine associations between patient characteristics and risk of hemorrhage. RESULTS: A total of 50 patients underwent 75 embolization procedures. Forty-six post-embolization MRIs were available for review. There were four hemorrhages and 100% of those presented with FHV. In contrast, only 11.9% of embolization procedures without post-procedural hemorrhage had FHVs on MRI. In total, 18.7% of embolizations led to some morbidity or mortality, with only 6.7% leading to permanent morbidity or mortality. In bivariate analysis, only the presence of FHVs was correlated with the risk of hemorrhage (p < 0.05). CONCLUSIONS: This is the first series to describe the finding of hyperintense blood vessels on FLAIR imaging after embolization of BAVMs and correlate it with hemorrhage post embolization. This finding can help guide practitioners and potentially identify patients at risk of delayed hemorrhage post embolization.

Quantitative magnetic resonance angiography as an alternative imaging technique in the assessment of cerebral vasospasm after subarachnoid hemorrhage.

INTRODUCTION: The major mechanism of morbidity of delayed cerebral ischemia after subarachnoid hemorrhage (SAH) is considered to be severe vasospasm. Quantitative MRA (QMRA) provides direct measurements of vessel-specific volumetric blood flow and may permit a clinically relevant assessment of the risk of ischemia secondary to cerebral vasospasm. PURPOSE: To evaluate the utility of QMRA as an alternative imaging technique for the assessment of cerebral vasospasm after SAH. METHODS: QMRA volumetric flow rates of the anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA) were compared with vessel diameters on catheter-based angiography. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of QMRA for detecting cerebral vasospasm was determined by receiver-operating characteristic curves. Spearman correlation coefficients were calculated for QMRA flow versus angiographic vessel diameter. RESULTS: Sixty-six vessels (10 patients) were evaluated with QMRA and catheter-based angiography. The median percent QMRA flow of all vessels with angiographic vasospasm (55.0%, IQR 34.3-71.6%) was significantly lower than the median percent QMRA flow of vessels without vasospasm (91.4%, IQR 81.4-100.4%) (p < 0.001). Angiographic vasospasm reduced QMRA-assessed flow by 23 ± 5 (p = 0.018), 95 ± 12 (p = 0.042), and 16 ± 4 mL/min (p = 0.153) in the ACA, MCA, and PCA, respectively, compared to vessels without angiographic vasospasm. The sensitivity, specificity, PPV, and NPV of QMRA for the discrimination of cerebral vasospasm was 84%, 72%, 84%, and 72%, respectively, for angiographic vasospasm >25% and 91%, 60%, 87%, and 69%, respectively, for angiographic vasospasm >50%. The Spearman correlation indicated a significant association between QMRA flows and vessel diameters (rs = 0.71, p < 0.001). CONCLUSION: Reduction in QMRA flow correlates with angiographic vessel narrowing and may be useful as a non-invasive imaging modality for the detection of cerebral vasospasm after SAH.

Utility of quantitative magnetic resonance angiography and non-invasive optimal vessel analysis for identification of complications and long-term hemodynamic changes in post-pipeline embolization patients.

INTRODUCTION: Quantitative magnetic resonance angiography and non-invasive optimal vessel analysis serve as powerful tools to collect and analyze hemodynamic data from pipeline embolization patients. At our institution, patients receive post-embolization quantitative magnetic resonance angiography within 24 h of treatment and within 6 months for follow-up to evaluate pipeline patency. Here, we aim to elucidate the long-term hemodynamic changes following pipeline embolization device placement and report two cases in which in-stent stenosis was detected. METHODS: Medical records of patients who underwent pipeline embolization device placement for an internal carotid artery aneurysm between 2017 and 2019 were reviewed. Patients who received post-procedure NOVA and follow-up NOVA were included in the study (n = 32). Location and size of aneurysm, number of pipeline embolization device deployed, and complications were collected along with the non-invasive optimal vessel analysis report (flow volume rate (ml/min), mean, systolic, and diastolic flow velocities (cm/s), and vessel diameter (mm)). Internal carotid artery vessel flow rate was measured proximal to the pipeline embolization device. Derivations of hemodynamic parameters (pulsatility index, Lindegaard ratio, and wall shear stress) were calculated. RESULTS: The middle cerebral artery mean and diastolic flow velocities were significantly lower on the follow-up NOVA compared to the post-procedure NOVA. Moreover, follow-up NOVA demonstrated lower middle cerebral artery wall shear stress on the side with flow diversion compared to the post-procedure NOVA. In-stent stenosis, requiring intervention, was detected in two patients on follow-up NOVA. One patient had a successful balloon angioplasty of the stented internal carotid artery that resolved her stenosis. However, the second patient developed progressive stenosis and expired despite intervention. CONCLUSION: Long-term hemodynamic adaptations post-pipeline embolization device demonstrate decreased wall shear stress and decreased mean and diastolic flow velocities in the distal middle cerebral artery, which suggest decreasing velocity of blood flow with endothelialization of the device. Furthermore, follow-up NOVA is a useful tool for detecting potential flow-related complications such as in-stent stenosis.

Quantitative magnetic resonance angiography to assess post embolization hemodynamics following pipeline embolization.

INTRODUCTION: Delayed intraparenchymal hemorrhage is a known complication of the Pipeline Embolization device (PED); however, its etiology is unclear and some have suggested it is a flow related phenomenon. Quantitative magnetic resonance angiography (QMRA) serves as a powerful tool to collect and analyze hemodynamic data. We report a detailed characterization of short-term hemodynamics after PED placement. METHODS: Patients who underwent PED placement for a distal internal carotid artery (ICA) aneurysm between 2017 to 2019 with post embolization QMRA were reviewed. Aneurysm characteristics, flow volume rate (ml/min), mean, systolic, and diastolic flow velocities (cm/s), vessel diameter (mm), pulsatility index, Lindegaard ratio, and wall shear stress (WSS) were collected. RESULTS: A total of 67 patients were included. Post-procedure patients were found to have a significantly lower ICA flow on the side with flow diversion when compared to the side without flow diversion (218 vs. 236.3; P < 0.05). Average ICA flow after flow diversion for aneurysms >2 cm was significantly lower when compared to the untreated side (187.7 vs. 240.4; P < 0.05). There was no difference in MCA or ACA flow or velocity. WSS was significantly lower in the treated ICA (8.2 vs. 9.0; P < 0.05). Lindegaard ratio was not different in the treated vs. contralateral untreated sides. CONCLUSION: PED placement for distal ICA aneurysms results in lower flow, mean velocity, and WSS when compared to the contralateral untreated ICA. This is not demonstrated distal to the Pipeline device in the ACA or MCA territories. Ultimately these findings suggest hemodynamic changes are not a cause of PED complications.

Single institution early clinical experience with the Scepter Mini balloon catheter.

BACKGROUND: The use of liquid embolic agents in the endovascular treatment of dural arteriovenous (dAVFs) fistulas and brain arteriovenous malformations (AVMs) has become common practice. The use of dual lumen balloon microcatheters has greatly improved the efficacy of liquid embolization. The purpose of this series is to discuss our early experience with the Scepter Mini dual lumen balloon microcatheter. METHODS: A retrospective chart review was performed of all patients who underwent embolization with the Scepter Mini dual lumen balloon at a single institution. Technical details and procedural complications were recorded for each case. RESULTS: In total, 10 Scepter Mini dual lumen balloon microcatheters were used in nine patients. All patients except two were treated for AVMs. Technical success was achieved in all but one case where one balloon had to be discarded due to precipitation of the tantalum powder. Average vessel diameter where the balloon was inflated was 1.1 mm (0.8-2.4 mm). It provided flow arrest in 100% of cases with no cases of reflux of embolic material. Balloon "jump back" was found to occur in 44.4% (4/9) of cases. Seven out of nine cases used Onyx, and two cases used n-butyl cyanoacrylate. CONCLUSIONS: The Scepter Mini is a new dual lumen balloon ideal for distal access and can be used for embolization with liquid embolic agents with a high degree of technical success. Its great benefit is the immediate and safe flow arrest of distal vasculature upon balloon inflation. One important consideration for effective embolization is early identification of balloon jump back.

Technical aspects of combined intrasaccular and endoluminal flow diversion.

INTRODUCTION: The concurrent use of endoluminal flow diversion with coils is a viable option when treating complex or large aneurysms. Alternatives to coil embolization as an adjunctive treatment are currently limited. The Food and Drug Administration recently approved the Woven EndoBridge (WEB) device (Microvention, Aliso Viejo, California) as an intrasaccular flow diverter for wide-neck bifurcation aneurysms. We present the technical aspects of combined WEB device plus endoluminal flow diversion for the treatment of complex wide-necked intracranial aneurysms. METHODS: A retrospective chart review of all patients treated via intrasaccular flow diversion at a single institution over the last 12 months was performed. RESULTS: In total, seven patients underwent treatment of eight aneurysms via combined intrasaccular and endoluminal flow diversion. Of the seven patients, six were treated in a single setting. The most common aneurysm location was the posterior communicating artery. The majority of the aneurysms required steam shaping of the Via deployment catheter to place the WEB device orthogonally to the aneurysm dome. There were no complications. CONCLUSIONS: We believe this is one of the first series reporting the combined use of the WEB device and endoluminal flow diversion for the treatment of intracranial aneurysms. This series demonstrates that the concurrent use of the WEB device with endoluminal flow diversion is safe for achieving immediate aneurysm treatment and may enhance the long-term durability in complex aneurysms.

Portable Magnetic Resonance Imaging for ICU Patients.

OBJECTIVES: Patients in ICUs often require neuroimaging to rule out a wide variety of intracranial problems. CT may be available in the ICU itself, but MRI has greater sensitivity for many conditions that affect the brain. However, transporting patients who are on ventilators and other life-sustaining devices is a labor-intensive process and involves placing the patient at risk for adverse events. This is a report of portable MRI in a clinical setting. DESIGN: This is a prospective, nonrandomized, observational study at one institution, utilizing a 0.064-T, self-shielding, portable MRI in ventilated patients in an ICU setting. SETTING: Academic medical center. PATIENTS: Nineteen patients with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection. Patients selected for imaging had any of the following: 1) unexplained encephalopathy or coma, 2) seizures, 3) focal neurologic deficit, or 4) abnormal head CT. Imaging was performed in each patient's ICU room with a portable, self-shielding, 0.064-T MRI. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among 19 patients, 20 MRI scans in seven ICUs were acquired between April 13, 2020, and April 23, 2020. No adverse events to patients or staff from MRI acquisition were reported. In 12 patients, abnormal findings were seen, which included increased fluid attenuated inversion recovery signal (n = 12), hemorrhage (n = 3), and diffusion-weighted imaging positivity (n =3). Imaging led to changes in clinical management in five patients. CONCLUSIONS: In this case series of patients, use of portable MRI has been found to be safe, feasible, and led to changes in clinical management based on imaging results. However, future studies comparing results with other imaging modalities are required to understand fully the extent of its clinical utility.

Waves of Pain Relief: A Systematic Review of Clinical Trials in Spinal Cord Stimulation Waveforms for the Treatment of Chronic Neuropathic Low Back and Leg Pain.

In the United States, chronic low back pain affects up to 37% of adults and is a multibillion dollar health care expenditure. Spinal cord simulation (SCS) has been established as an effective treatment alternative for chronic neuropathic low back and leg pain, especially for patients with failed back surgery syndrome or chronic regional pain syndrome. The field of SCS has rapidly advanced such that analgesia can now be achieved through numerous different waveforms, each claiming to offer improved outcomes. These waveforms include traditional paresthesia-based SCS (<100 Hz), paresthesia-free high-frequency SCS (5-10 kHz), burst SCS, and subperception SCS (1-5 kHz). Level 1 evidence critically evaluating the efficacy of these different waveforms is lacking. We conducted a systematic review of the literature in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify all randomized controlled trials of SCS in the treatment of chronic neuropathic low back and leg pain, failed back surgery syndrome, or chronic regional pain syndrome. Of 38 eligible studies reviewed, 13 randomized controlled trials were finally included in our systematic review. We reviewed evidence from randomized controlled trials in the field of SCS that have established paresthesia-based SCS, paresthesia-free high-frequency SCS, burst SCS, and subperception SCS as viable treatment options for chronic neuropathic low back and leg pain. We critically evaluated evidence that claims to support the use of one waveform over another and reviewed the literature on patient preference for different waveforms.

Statewide Trends in Intracranial Pressure Monitor Use in 36,915 Patients with Severe Traumatic Brain Injury in a Mature Trauma System over the Past 18 Years.

OBJECTIVE: Intracranial pressure (ICP)-guided therapy has been the mainstay of treatment of patients with severe traumatic brain injury (TBI), but recent data have questioned its efficacy. The aim of this study was to demonstrate trends in compliance to TBI guidelines and use of ICP-guided care in a mature trauma system. METHODS: A retrospective analysis was conducted of 36,915 patients with severe TBI collected by the Pennsylvania Trauma Systems Foundation. The registry includes all patients >18 years old with a diagnosis of TBI with a Glasgow Coma Scale score ≤8 who were admitted from January 2000 to December 2017. RESULTS: Of 36,915 patients, 73.6% were men with a median age of 43.0 ± 21.3 years. An ICP monitor was placed in 16.3% of all patients. The rate of ICP monitoring ranged from 17.8% of patients in 2000-2004 to 16.7% in 2005-2009, 16.4% in 2010-2014, and 12.8% in 2015-2017 (P < 0.001). The most statistically significant decrease was noted from 2014 (16.4%) to 2015 (14.1%, P = 0.042). The percent decrease in ICP monitoring from 2000-2014 to 2015-2017 was equivalent for patients with Glasgow Coma Scale scores of 3-5 (-4.0%) and 6-8 (-4.5%). CONCLUSIONS: As studies emerged that demonstrated unclear benefit of ICP monitoring in improving care in patients with severe TBI, there was a significant statewide decline in the use of ICP monitoring after 2014 among all TBI subpopulations despite noteworthy limitations in the aforementioned studies and clear recommendations from the Brain Trauma Foundation guidelines.

Predictors of hospital-associated complications prolonging ICU stay in patients with low-grade aneurysmal subarachnoid hemorrhage.

OBJECTIVE: The authors sought to determine the predictors of late neurological and hospital-acquired medical complications (HACs) in patients with low-grade aneurysmal subarachnoid hemorrhage (aSAH). METHODS: The authors conducted a retrospective study of 424 patients with low-grade aSAH admitted to their institution from 2008 to 2015. Data collected included patient comorbidities, Hunt and Hess (HH) grade, ICU length of stay (LOS), and complications. A logistic regression analysis was performed to determine the predictors for neurological and hospital-associated complications. RESULTS: Out of 424 patients, 50 (11.8%) developed neurological complications after the first week, with a mean ICU stay of 16.3 ± 6.5 days. Of the remaining 374 patients without late neurological complications, 83 (22.2%) developed late HACs with a mean LOS of 15.1 ± 7.6 days, while those without medical complications stayed 11.8 ± 6.2 days (p = 0.001). Of the 83 patients, 55 (66.3%) did not have any HACs in the first week. Smoking (p = 0.062), history of cardiac disease (p = 0.043), HH grade III (p = 0.012), intraventricular hemorrhage (IVH) (p = 0.012), external ventricular drain (EVD) placement (p = 0.002), and early pneumonia/urinary tract infection (UTI)/deep vein thrombosis (DVT) (p = 0.001) were independently associated with late HACs. Logistic regression showed early pneumonia/UTI/DVT (p = 0.026) and increased HH grade (p = 0.057) to be significant risk factors for late medical complications. CONCLUSIONS: While an extended ICU admission allows closer monitoring, low-grade aSAH patients develop HACs despite being at low risk for neurological complications. The characteristics of low-grade aSAH patients who would benefit from early discharge are reported in detail.