Search

Aneurysmal subarachnoid hemorrhage (SAH) continues to be a difficult cerebrovascular disease with limited pharmacologic treatment options. Cerebral vasospasm (CV) and delayed cerebral ischemia (DCI) are leading causes of morbidity and mortality after SAH. Despite the advances in the understanding of its pathophysiology and tremendous efforts to date, nimodipine is currently the sole Food and Drug Administration-approved treatment for patients with SAH, with benefits that are marginal at best. The neuromodulation therapies are promising, especially those that target CV and DCI to improve functional outcomes. The aim of this review is therefore to summarize the available evidence for each type of neuromodulation for CV and DCI, with a special focus on its pathophysiological mechanisms, in addition to their clinical utility and drawbacks, which we hope will lead to future translational therapy options after SAH.We conducted a comprehensive review of preclinical and clinical studies demonstrating the use of neuromodulation for SAH. The literature search was performed using PubMed, Embase, and ClinicalTrials.gov. A total of 21 articles published from 1992 to 2021 and eight clinical trials were chosen.The studies reviewed provide a compelling demonstration that neuromodulation is a potentially useful strategy to target multiple mechanisms of DCI and thus to potentially improve functional outcomes from SAH. There are several types of neuromodulation that have been tested to treat CV and DCI, including the trigeminal/vagus/facial nerve stimulation, sphenopalatine ganglion and spinal cord stimulation, transcranial direct electrical stimulation, transcutaneous electrical neurostimulation, and electroacupuncture. Most of them are in the preclinical or early phases of clinical application; however, they show promising results.DCI has a complex pathogenesis, making the unique anatomical distribution and pleiotropic capabilities of various types of neuromodulation a promising field of study. We may be at the cusp of a breakthrough in the use of these techniques for the treatment of this stubbornly difficult disease.

BackgroundRapid time to reperfusion is essential to minimize morbidity and mortality in acute ischemic stroke due to large vessel occlusion (LVO). We aimed to evaluate the workflow times when utilizing a direct-to-angiography suite (DTAS) pathway for patients with suspected stroke presenting at a comprehensive stroke center compared with a conventional CT pathway.MethodsWe developed a discrete-event simulation (DES) model to evaluate DTAS workflow timelines compared with a conventional CT pathway, varying the admission NIHSS score treatment eligibility criteria. Model parameters were estimated based on 2 year observational data from our institution. Sensitivity analyses of simulation parameters were performed to assess the impact of patient volume and baseline utilization of angiography suites on workflow times utilizing DTAS.ResultsSimulation modeling of stroke patients (SimStroke) demonstrated door-to-reperfusion time savings of 0.2–3.5 min (p=0.05) for a range of DTAS eligibility criteria (ie, last known well to arrival ConclusionsThe results of the SimStroke model showed comparable time intervals for door-to-reperfusion for DTAS compared with a conventional stroke care pathway. However, the DTAS pathway was very sensitive to baseline angiography suite utilization, with even a 10% increase eliminating the advantages of DTAS compared with the conventional pathway. Given the minimal time savings modeled here, further investigation of implementing the DTAS pathway in clinical care is warranted.

BackgroundBleb presence in intracranial aneurysms (IAs) is a known indication of instability and vulnerability.ObjectiveTo develop and evaluate predictive models of bleb development in IAs based on hemodynamics, geometry, anatomical location, and patient population.MethodsCross-sectional data (one time point) of 2395 IAs were used for training bleb formation models using machine learning (random forest, support vector machine, logistic regression, k-nearest neighbor, and bagging). Aneurysm hemodynamics and geometry were characterized using image-based computational fluid dynamics. A separate dataset with 266 aneurysms was used for model evaluation. Model performance was quantified by the area under the receiving operating characteristic curve (AUC), true positive rate (TPR), false positive rate (FPR), precision, and balanced accuracy.ResultsThe final model retained 18 variables, including hemodynamic, geometrical, location, multiplicity, and morphology parameters, and patient population. Generally, strong and concentrated inflow jets, high speed, complex and unstable flow patterns, and concentrated, oscillatory, and heterogeneous wall shear stress patterns together with larger, more elongated, and more distorted shapes were associated with bleb formation. The best performance on the validation set was achieved by the random forest model (AUC=0.82, TPR=91%, FPR=36%, misclassification error=27%).ConclusionsBased on the premise that aneurysm characteristics prior to bleb formation resemble those derived from vascular reconstructions with their blebs virtually removed, machine learning models can identify aneurysms prone to bleb development with good accuracy. Pending further validation with longitudinal data, these models may prove valuable for assessing the propensity of IAs to progress to vulnerable states and potentially rupturing.

Traumatic peri-contusional penumbra represents crucial targets for therapeutic interventions after traumatic brain injury (TBI). Current resuscitative approaches may not adequately alleviate impaired cerebral microcirculation and, hence, compromise oxygen delivery to peri-contusional areas. Low-frequency oscillations in cerebral blood flow (CBF) may improve cerebral oxygenation in the setting of oxygen deprivation. However, no method has been reported to induce controllable oscillations in CBF and it hasn’t been applied as a therapeutic strategy. Electrical stimulation of the trigeminal nerve (TNS) plays a pivotal role in modulating cerebrovascular tone and cerebral perfusion. We hypothesized that TNS can modulate CBF at the targeted frequency band via the trigemino-cerebrovascular network, and TNS-induced CBF oscillations would improve cerebral oxygenation in peri-contusional areas. In a rat model of TBI complicated by hemorrhagic shock, TNS-induced CBF oscillations conferred significant preservation of peri-contusional tissues leading to reduced lesion volume, attenuated hypoxic injury and neuroinflammation, increased eNOS expression, improved neurological recovery and better 10-day survival rate, despite not significantly increasing CBF as compared with those in immediate and delayed resuscitation animals. Our findings indicate that low-frequency CBF oscillations enhance cerebral oxygenation in peri-contusional areas, and play a more significant protective role than improvements in non-oscillatory cerebral perfusion or volume expansion alone.

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 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 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.

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.

Introduction. The World Health Organization declared COVID-19 a global pandemic last year. While a clear impact of COVID-19 on the declining stroke volume has been reported, its overall impact on stroke presentation and clinical outcomes has not been established. The purpose of this study was to assess the impact of COVID-19 on acute ischemic stroke volume, presentation, treatment, and outcomes at comprehensive stroke centers. Methods. A retrospective review of patients with a discharge diagnosis of acute ischemic stroke from the Get With The Guidelines database was performed from January 1, 2019, to July 1, 2020. The following time periods were defined: Pre-COVID (January/February), Peak-COVID (March/April), and Post-COVID (May/June). Bivariate analyses were performed comparing the 2020 and 2019 time periods to determine differences in stroke volume, presentation, treatment, and outcomes. Results. Stroke volumes were significantly lower during the Peak-COVID period in 2020 compared to that in 2019, with an absolute decline of 49.5% ( P < 0.001 ). Patients were more likely to present after 24 hours from last known well during the 2020 Peak-COVID period ( P = 0.03 ). However, there was not a significant difference in the rate of treatment with either the tissue plasminogen activator (tPA) or mechanical thrombectomy during the Peak-COVID period. Interestingly, relative treatment rates increased during the 2020 Post-COVID period to 11.4% ( P = 0.01 ). Conclusions. The overall ischemic stroke volume decreased during the pandemic, and patients had a tendency to present later, beyond eligible treatment windows. However, rates of treatment, patient demographics, and stroke outcomes did not significantly change when compared to the prior year.

Background With recent advances in endovascular treatments of brain aneurysms such as flow diverters, the role of cerebral revascularization needs to be re-evaluated. Objective To evaluate the contemporary indications and outcomes of cerebral revascularization for brain aneurysms. Methods A retrospective evaluation of a prospectively maintained database was performed to review clinical and imaging data of all the patients who underwent cerebral revascularization for brain aneurysms over the past 10 yr. Results Among 174 cerebral revascularizations, 40 (in 36 patients) were done for the treatment of aneurysms. In total, 9 patients underwent combined endovascular treatment and surgical revascularization. Immediate aneurysm occlusion was achieved in 30 patients (83.3%). Immediate postoperative bypass patency was confirmed in 33 patients (92%). Postoperative neurological deficit was observed in 4 patients (11.1%). There were 2 mortalities in the postoperative period. Aneurysm total occlusion rate was 91% at 1 yr. Thirty patients had 1 yr clinical and radiological follow-up. Clinical evaluations showed modified Rankin Scale 2 or less in 25 patients at 1 yr. Bypass patency was confirmed in 27 (90%). Patients with fair/poor outcome were all in the subarachnoid hemorrhage group. Twenty-one patients had follow-up studies for 3 yr or beyond with no evidence of stroke or aneurysm recurrence. Conclusion Our results support that cerebral revascularization can be regarded as a viable and durable treatment option for these challenging aneurysms with acceptable morbidity. Cerebral bypass should be offered in selected cases where standard endovascular or surgical treatment is not efficacious or curative.

Objective To replace educational opportunities lost during the coronavirus disease 2019 (COVID-19) pandemic, the Department of Neurosurgery at Lenox Hill Hospital produced an open-access webinar series (“BRAINterns”) that covered a broad range of health care topics with a focus on neurosurgery. Methods This 8-week webinar series ran from July 1 to August 28, 2020. An optional exit survey was distributed to participants. Data were analyzed to characterize and better understand trends among a global cohort of participants. Results A total of 16,484 people registered for BRAINterns, and 6675 took the survey (40.5% response rate). Responders represented 87 countries, of which the majority were from the United States and Canada (90.48%, n = 6039). Responders were primarily female (82.9%, n = 5521). Racial and ethnic representation was majority Asian (42%, n = 2798), followed by White (22.7%, n = 1514), Hispanic/Latino (16.2%, n = 1080), and Black and African American (7.7%, n = 516). Participants reported hearing about BRAINterns through various social media platforms (72.18%, n = 4818)—the most popular was TikTok (33.4%, n = 2232). Overall, 93.4% of participants reported that the course was a good use of their time during the pandemic, and 86.7% reported that the course helped replace lost opportunities. Conclusions These data demonstrate that webinar-based education is an effective method of expanding access to careers in medicine and in particular, neurosurgery, to traditionally underrepresented populations. Social media can be a powerful tool to combat barriers to early exposure and vastly improve diversity within the field.

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.

lthough intravenous contrast in neuroimaging has become increasingly important in selecting patients for stroke treatment, clinical concerns remain regarding contrast-associated acute kidney injury (CA-AKI). Given the increasing utilization of CT angiography and/or perfusion coupled with cerebral angiography, the purpose of this study was to assess the association of CA-AKI and multi-dose iodinated contrast in acute ischemic stroke (AIS) patients.etrospective review of AIS patients at a comprehensive stroke center was performed from January 2018 to December 2019. Data collection included patient demographics, stroke risk factors, stroke severity, discharge disposition, modified Rankin Scale, contrast type/volume, and creatinine levels (baseline, 48-72 h). CA-AKI was defined as creatinine increase ≥ 25 % from baseline. Bivariate analyses and multivariable logistic regression models were implemented to compare AIS patients with multi-dose and single-dose contrast.Of 440 AIS patients, 215 (48.9 %) were exposed to a single-dose contrast, and 225 (51.1 %) received multi-dose. In single-dose patients, CA-AKI at 48/72 h was 9.7 %/10.2 % compared to 8.0 %/8.9 % in multi-dose patients. Multi-dose patients were significantly more likely to receive a higher volume of contrast (mean 142.1 mL versus 80.8 mL; p lt; 0.001), but there was no significant difference in their creatinine levels or CA-AKI. NIHSS score (OR=1.08, 95 % CI=[1.04,1.13]), and patient transfer from another hospital (OR=3.84, 95 % CI=[1.94,7.62]) were significantly associated with multi-dose contrast.No significant association between multi-dose iodinated contrast and CA-AKI was seen in AIS patients. Concerns of CA-AKI should not deter physicians from pursuing timely and appropriate contrast-enhanced neuroimaging that may optimize treatment outcomes in AIS patients.

Posterior fossa dural arteriovenous fistulas (dAVFs) are rare vascular lesions with variable risk of hemorrhage, mostly depending on the pattern of the venous drainage. While endovascular embolization is the mainstay treatment for most dAVFs, some posterior fossa lesions require a multidisciplinary approach including surgery. The goal of our study was to examine the outcome of an interdisciplinary treatment for posterior fossa dAVFs. A retrospective review of patients treated for posterior fossa dAVFs was conducted. A total of 28 patients with a mean age of 57.8 years were included. Patients presented with a Cognard grade I in 2 (7%), II a in 5 (18 %), II b in 7 (25%), II a + b in 5 (18%), III in 3 (11%), and IV in 6 (21%) cases. Hemorrhage was the initial presentation in 2 (22%) patients with Cognard grade IV, in 3 with Cognard grade III (33%), in 1 (11%) with Cognard II a + b, and 3 (33%) with Cognard II b. A complete angiographic cure was achieved in 24 (86%) patients—after a single-session embolization in 16 (57%) patients, multiple embolization sessions in 2 (7%), a multimodal treatment with embolization and surgical disconnection in 3 (11%), and with an upfront surgery in 3 (11%). Complete long-term obliteration was demonstrated in 18/22 (82%) at the mean follow-up of 17 months. Fistulas were converted into asymptomatic Cognard I lesion in 4 (14%) patients. Posterior fossa dAVFs represent a challenging vascular pathology; however, despite their complexity, an interdisciplinary treatment can achieve high rates of angiographic and symptomatic cure with low morbidity and mortality rates. Long-term surveillance is warranted as late recurrences may occur.

Disappearing intracranial aneurysms are rare and have not been extensively reported in the literature. They are often small or partially thrombosed and carry a significant risk of recurrence. We discuss a unique case of a 65-year-old woman who presented in 2006 with a subarachnoid hemorrhage and was found to have a ruptured posterior communicating artery and an unruptured P1 aneurysm. Follow-up angiography and imaging showed no changes in the size of a left P1 aneurysm for 11 years (2006–2017). However, in 2021, 15 years after initial presentation, no aneurysm was seen on magnetic resonance angiography, and subsequent digital subtraction angiography in 2022 showed almost complete disappearance of the unruptured P1 aneurysm. Literature review reveals only six reported cases during which a small, unruptured anterior circulation aneurysm disappeared, or regressed on follow-up imaging and no reported cases in the posterior circulation.

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.

Angiographic treatment of asymptomatic cerebral vasospasm (CVS) in aneurysmal subarachnoid hemorrhage remains controversial. We sought to investigate its relationship with the development of delayed cerebral ischemia.Consecutive patients admitted between July 2017 and June 2019, with a diagnosis of aneurysmal subarachnoid hemorrhage, were retrospectively analyzed. The rate of development of delayed cerebral ischemia was compared between a group of patients who underwent cerebral angiography for asymptomatic CVS and those who did not. The Mann-Whitney U test or χThirty-seven of the 94 patients with aneurysmal subarachnoid hemorrhage were screened for CVS, of whom 16 (43%) had moderate-severe vasospasm. When patients who underwent therapeutic cerebral angiography were compared with those who did not and after adjusting for sex, age, and grade of subarachnoid hemorrhage, treatment was not found to be significantly associated with delayed cerebral ischemia (hazard ratio = 0.82, 95% confidence interval: 0.19-3.52, P = 0.79). We found that the median length of stay in the intensive care unit and hospital increased significantly with the severity of CVS (P 0.001).Cerebral angiography has a low rate of detecting moderate-severe CVS in asymptomatic patients. Moreover, there was no statistically significant difference in the rate of delayed cerebral ischemia between asymptomatic patients treated versus those not treated for CVS. There was significant association between the severity of CVS and the intensive care unit and hospital length of stay. More studies are needed to evaluate the utility of treating asymptomatic CVS in high-grade aneurysmal subarachnoid hemorrhage.

Delayed cerebral ischemia (DCI) is the most consequential secondary insult after aneurysmal subarachnoid hemorrhage (SAH). It is a multifactorial process caused by a combination of large artery vasospasm and microcirculatory dysregulation. Despite numerous efforts, no effective therapeutic strategies are available to prevent DCI. The trigeminal nerve richly innervates cerebral blood vessels and releases a host of vasoactive agents upon stimulation. As such, electrical trigeminal nerve stimulation (TNS) has the capability of enhancing cerebral circulation. OBJECTIVE: To determine whether TNS can restore impaired cerebral macrocirculation and microcirculation in an experimental rat model of SAH. METHODS: The animals were randomly assigned to sham-operated, SAH-control, and SAH-TNS groups. SAH was induced by endovascular perforation on Day 0, followed by KCl-induced cortical spreading depolarization on day 1, and sample collection on day 2. TNS was delivered on day 1. Multiple end points were assessed including cerebral vasospasm, microvascular spasm, microthrombosis, calcitonin gene-related peptide and intercellular adhesion molecule-1 concentrations, degree of cerebral ischemia and apoptosis, and neurobehavioral outcomes. RESULTS: SAH resulted in significant vasoconstriction in both major cerebral vessels and cortical pial arterioles. Compared with the SAH-control group, TNS increased lumen diameters of the internal carotid artery, middle cerebral artery, and anterior cerebral artery, and decreased pial arteriolar wall thickness. Additionally, TNS increased cerebrospinal fluid calcitonin gene-related peptide levels, and decreased cortical intercellular adhesion molecule-1 expression, parenchymal microthrombi formation, ischemia-induced hypoxic injury, cellular apoptosis, and neurobehavioral deficits. CONCLUSION: Our results suggest that TNS can enhance cerebral circulation at multiple levels, lessen the impact of cerebral ischemia, and ameliorate the consequences of DCI after SAH.

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 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.

Background The use of an exoscope in neurosurgical procedures has been proposed to improve ergonomics and to overcome the limitations faced with the microscope and endoscope. However, there remains scarcity of data regarding its surgical utility and outcomes. Objectives The authors report their experience and evaluate the surgical outcomes using a high-definition 2-dimensional (HD-2D) stereotactic exoscope in the management of various cranial and spinal pathologies. Methods We retrospectively identified patients who underwent neurosurgical procedures using the HD-2D stereotactic exoscope over a 2-year period. Demographic and surgical characteristics were analyzed. Results Twenty-nine patients (70.7%) underwent cranial surgery, and 12 patients (29.3%) underwent spine surgery. In patients having brain tumor removal, gross total resection was achieved in 18 patients (62.1%); with an overall average pathology size of 4.2±1.6 cm. Adjuvant utilization of the microscope was required in 4 cranial cases (13.8%) to ensure optimal resection rate. Three complications and 2 mortalities were encountered in the cranial group during a mean follow-up of 4.6±3.3 months. In the spinal cohort, the HD-2D stereotactic exoscope was utilized for anterior decompression and fusion (n=5), posterior decompression and fusion (n=5), and microdiscectomy and foraminotomy (n=2). No complications were encountered in the spinal group during a mean follow-up of 3.8±2.7 months. Conclusion The HD-2D stereotactic exoscope offers a wider field of view, greater mean focal distance, enhanced ergonomics, and immersive stereotactic visual experience. The lack of stereopsis remains the principal limitation of its use, and further optimization of surgical outcomes might be achieved with newer 3D models.

The trigeminal nerve, the fifth cranial nerve, is known to innervate much of the cerebral arterial vasculature and significantly contributes to the control of cerebrovascular tone in both healthy and diseased states. Previous studies have demonstrated that stimulation of the trigeminal nerve (TNS) increases cerebral blood flow (CBF) via antidromic, trigemino-parasympathetic, and other central pathways. Despite some previous reports on the role of the trigeminal nerve and its control of CBF, there are only a few studies that investigate the effects of TNS on disorders of cerebral perfusion (i.e., ischemic stroke, subarachnoid hemorrhage, and traumatic brain injury). In this mini review, we present the current knowledge regarding the mechanisms of trigeminal nerve control of CBF, the anatomic underpinnings for targeted treatment, and potential clinical applications of TNS, with a focus on the treatment of impaired cerebral perfusion.

Background Metastatic subdural hematoma with dural metastasis in the setting of an underlying malignancy is a rare condition that is difficult to diagnose and associated with a poor prognosis. Knowledge of this rare entity is of a paramount importance to neurosurgeons, as its diagnosis may affect the management plan and overall survival. Here, we report a rare case of atraumatic subdural hematoma with dural metastasis in a patient with poorly differentiated adenocarcinoma of unknown origin. Case Description A 34-year-old man presented with an insidious onset of headaches, severe light headedness, progressive low back pain, and generalized weakness for 2 weeks. On imaging, he was found to have left-sided acute on chronic subdural hematoma with midline shift. The patient underwent surgical evacuation of the hematoma and the subdural membrane was biopsied. Histopathologic examination revealed metastatic poorly differentiated adenocarcinoma of unclear origin. A full metastatic workup was unremarkable. Conclusions Metastatic subdural hematoma with dural metastasis should be included in differential diagnosis of subdural hematoma, especially in patients with atypical presentation and in the presence of an underlying malignancy, as it may affect the management plan and overall survival.

Introduction Current methods for angioplasty and stenting of the intracranial vasculature for neurointervention are limited. The Wingspan Stent System is Food and Drug Administration (FDA) approved with human device exemption for a limited patient group and despite numerous prospective registries and trials demonstrating reasonable safety, still carries warnings from the FDA for its use. Given these limitations, we present the technical nuances and outcomes of the off-label use of the Resolute Onyx drug-eluting stent (DES) for neurointerventional purposes. Methods Retrospective chart review of all patients undergoing a neurointerventional procedure with the Resolute Onyx DES was done from January 2017–2021. The Resolute Onyx is a coronary balloon-mounted drug-eluting (zotarolimus) single wire laser cut stent. Technical details and procedural outcomes were collected. Results In total 40 patients had attempted placement of the Resolute Onyx DES with procedural success in 95% of patients. The most common vessel stented was the basilar artery, 30% (12/40). The most common indication was intracranial atherosclerotic disease in 62.5% (25/40) patients, followed by acute stroke in 17.5% (7/40) of patients. The technical and procedural outcomes were excellent with only one technical complication (2.5%). Conclusions This series describes the initial technical safety and utility of utilizing a new generation balloon-mounted drug-eluting stent for neurointerventional purposes. This stent offers the potential for improved navigability, delivery, and outcomes compared to current neurointerventional options and warrants further study.

Background The trigeminal nerve directly innervates key vascular structures both centrally and peripherally. Centrally, it is known to innervate the brainstem and cavernous sinus, whereas peripherally the trigemino-cerebrovascular network innervates the majority of the cerebral vasculature. Upon stimulation, it permits direct modulation of cerebral blood flow (CBF), making the trigeminal nerve a promising target for the management of cerebral vasospasm. However, trigeminally mediated cerebral vasodilation has not been applied to the treatment of vasospasm. Objective To determine the effect of percutaneous electrical stimulation of the infraorbital branch of the trigeminal nerve (pTNS) on the cerebral vasculature. Methods In order to determine the stimulus-response function of pTNS on cerebral vasodilation, CBF, arterial blood pressure, cerebrovascular resistance, intracranial pressure, cerebral perfusion pressure, cerebrospinal fluid calcitonin gene-related peptide (CGRP) concentrations, and the diameter of cerebral vessels were measured in healthy and subarachnoid hemorrhage (SAH) rats. Results The present study demonstrates, for the first time, that pTNS increases brain CGRP concentrations in a dose-dependent manner, thereby producing controllable cerebral vasodilation. This vasodilatory response appears to be independent of the pressor response induced by pTNS, as it is maintained even after transection of the spinal cord at the C5-C6 level and shown to be confined to the infraorbital nerve by administration of lidocaine or destroying it. Furthermore, such pTNS-induced vasodilatory response of cerebral vessels is retained after SAH-induced vasospasm. Conclusion Our study demonstrates that pTNS is a promising vasodilator and increases CBF, cerebral perfusion, and CGRP concentration both in normal and vasoconstrictive conditions.

Background Even in the modern endovascular era, the treatment of Vein of Galen Malformations (VOGM) is extremely challenging. While their natural history is very poor, endovascular embolization has emerged as the standard of care. These lesions often require multiple treatment sessions to decrease shunting, with each treatment including multiple pedicles. Here we present the first reported use of the Scepter Mini (Microvention, Aliso Viejo, CA) in the treatment of vein of Galen malformations. Clinical presentation A 7 month old female presented with an enlarging VOGM that was initially identified on prenatal ultrasound. Given the enlarging size of the lesion and failure to meet developmental milestones, the patient underwent planned endovascular embolization of the VOGM. The novel Scepter Mini balloon catheter was used for treatment of this lesion affording easy access to the target pedicle and immediate flow arrest which allowed for immediate cure of the lesion. Conclusion The novel Scepter Mini Balloon (Microvention, Aliso Viejo, CA) afforded excellent distal access with subsequent immediate flow arrest therefore facilitating endovascular cure. Initially, a staged approach was favored for the treatment of the lesion, but the flow arrest achieved by the Scepter mini facilitated immediate occlusion from a single pedicle.

Posterior fossa dural arteriovenous fistulas (dAVFs) are rare vascular lesions with variable risk of hemorrhage, mostly depending on the pattern of the venous drainage. While endovascular embolization is the mainstay treatment for most dAVFs, some posterior fossa lesions require a multidisciplinary approach including surgery. The goal of our study was to examine the outcome of an interdisciplinary treatment for posterior fossa dAVFs.A retrospective review of patients treated for posterior fossa dAVFs was conducted.A total of 28 patients with a mean age of 57.8 years were included. Patients presented with a Cognard grade I in 2 (7%), II a in 5 (18 %), II b in 7 (25%), II a + b in 5 (18%), III in 3 (11%), and IV in 6 (21%) cases. Hemorrhage was the initial presentation in 2 (22%) patients with Cognard grade IV, in 3 with Cognard grade III (33%), in 1 (11%) with Cognard II a + b, and 3 (33%) with Cognard II b. A complete angiographic cure was achieved in 24 (86%) patients-after a single-session embolization in 16 (57%) patients, multiple embolization sessions in 2 (7%), a multimodal treatment with embolization and surgical disconnection in 3 (11%), and with an upfront surgery in 3 (11%). Complete long-term obliteration was demonstrated in 18/22 (82%) at the mean follow-up of 17 months. Fistulas were converted into asymptomatic Cognard I lesion in 4 (14%) patients.Posterior fossa dAVFs represent a challenging vascular pathology; however, despite their complexity, an interdisciplinary treatment can achieve high rates of angiographic and symptomatic cure with low morbidity and mortality rates. Long-term surveillance is warranted as late recurrences may occur.

INTRODUCTION Beginning in March, 2020, hospitals across the majority of the United States were required to cancel all elective surgery in preparation for a surge of patients with the coronavirus disease of 2019 (COVID-19). A large number of neurosurgical patients with less than emergency conditions had their surgery postponed indefinitely. METHODS The Delphi method was used to obtain consensus. Twenty-two neurosurgeons actively practicing in two separate geographic regions of the United States where “black level” COVID-19 surges occurred (New York Metropolitan Area and Detroit, Michigan) participated. A total of 86 neurosurgical case scenarios were categorized into six tiers of priority: emergent or within 24 hours, within 48 hours, within 1 week, within 2 weeks, within one month, or post hospital crisis/more than 4 weeks. Consensus was defined as 75% of participants reaching an agreement. Majority opinion (>50% agreement) was also reported. RESULTS 67 of the 86 surgical scenarios (78%) reached a consensus agreement with 85 out of 86 scenarios reaching at least a majority opinion. Only one scenario (central cord syndrome) did not reach any agreement. CONCLUSION The NNPI developed in this study can assist neurosurgical departments in prioritizing the timing of surgery, whether it be due to a pandemic, or any other scenario where the normal work flow has been severely disrupted and resources are limited.

Introduction The concurrent use of the Pipeline Embolization Device (PED) with coils has been shown to be beneficial when treating complex or large aneurysms. Alternatives to coiling as an adjunctive treatment are currently limited. The FDA recently approved the Woven EndoBridge (WEB) (Microvention, Aliso Viejo, California) device as an intrasaccular flow diverter for wide neck bifurcation aneurysms (FDA). Here in we present the technical aspects of combined WEB plus PED for the treatment of 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 done. In total 34 aneurysms were treated via WEB intrasaccular flow diversion; however, only 7 of these aneurysms were treated with the pipeline embolization device as well. Technical aspects of each procedure were recorded. Results In total 6 patients underwent the treatment of 7 aneurysms via combined intrasaccular and endoluminal flow diversion. All aneurysm were treated in a single setting but for one patient. This patient came in with subarachnoid hemorrhage, had a WEB placed, and subsequently was found to have recanalized their aneurysm due to WEB compaction. This prompted placement of the a Pipeline 4 weeks after initial treatment. There were no complications associated with any treatment. Post embolization MRI/A showed no new infarcts in 3/7 patients and small punctate DWI changes in 4/7 patients with good stent flow in all cases. There were no bifurcation aneurysms: 5 posterior communicating, 1 superior hypophyseal, 1 vertebrobasilar. The majority of the aneurysms required steam shaping of the Via deployment catheter in order to place the WEB orthogonally to the aneurysm dome. The radial force of the Pipeline was able to push a herniated WEB device into the aneurysm in all but one case where a balloon was employed to angioplasty the stent. Conclusions We believe this is the first series reporting combined use of WEB and Pipeline for the treatment of intracranial aneurysms. Treatment failure rates of PED as a stand-alone treatment have been reported to be from 11.9% to 20%. Intrasaccular flow diversion with the WEB device allows for increased metal coverage at both the aneurysm neck, preventing inflow, and the aneurysm dome, protecting from rupture. For larger aneurysms the WEB device theoretically protects from a destabilizing mural thrombus. Also, in larger aneurysm were WEB devices have been shown to be less enduring, endoluminal remodeling provides a durable treatment. This series demonstrates the WEB device as a feasible and safe alternative to adjuvant coiling for achieving immediate intrasaccular flow diversion when using the PED. Disclosures T. White: None. K. Shah: None. J. Turpin: None. J. Katz: None. H. Woo: None.

Introduction Delayed cerebral ischemia (DCI) continues to be a challenging complication of subarachnoid hemorrhage. This study sought to examine the impact of intra-arterial therapy on patients with medically refractory DCI. More specifically it sought to determine comparative results of nicardipine and verapamil as well as to determine if there was a relationship between IA vasodilator dose and complication rate. Methods A retrospective chart review of all patients at a single institution undergoing endovascular IA therapy for vasospasm secondary to subarachnoid hemorrhage over a 30 month period was done. In total, 69 patients underwent 126 treatments for cerebral vasospasm in the setting of atraumatic subarachnoid hemorrhage (SAH). In total 91% of patients present with aneurysmal SAH while 9% had angiography negative SAH. 53.6% of patients had their aneurysm treated endovascularly. Median Hunt Hess grade was 3 and 88% of patients presented with Modified Fischer grade 3 or 4. Formal angiography was done in the setting of clinical vasospasm as determine by patients’ neurologic exams, velocity on transcranial doppler, and other clinical factors. The majority of patients underwent a single treatment (55%) while the most treatments for a single patient was 5 (4%). Results In total, 98% (123/126) of treatments led to an improved or stable neurological exam post treatment, and 3 patients developed a post-operative procedural neurological decline. Delayed cerebral ischemia, defined as a new neurological deficit, occurred in 55% (38/69) of patients in this cohort; however, the new neurological deficit was permanent in only 14% of patients (10/69). New infarcts were seen on imaging in 19% of patients (13/69) but were clinically silent in 3/60 patients. Patients with DCI were more likely to undergo multiple treatments of IA therapy (P 0.05). There was no differential risk of DCI in the nicardipine vs the verapamil group (P>0.05). Patients undergoing verapamil therapy were more likely to experience complications of IA therapy, 20% vs 5% in the nicardipine group (P Conclusion This report adds to the growing body of literature that endovascular rescue therapy offers a safe and effective option in managing medically refractory vasospasm in order to prevent DCI. Importantly, it also suggests that in select patients high dose therapy can be used for maximal benefit with a reasonable side effect profile. Importantly, this series also demonstrates an initial rate of DCI of 55% in patients with vasospasm undergoing IA therapy with only 14% of patient’s demonstrating permanent neurological deficit suggesting a significant overall benefit of treatment. The results of this initial study mandate further investigation into the safety and efficacy of intra-arterial verapamil and nicardipine for the treatment and prevention of DCI. More importantly it shows that dose optimization needs to be done prior to pursuing further trials. Disclosures T. White: None. J. Turpin: None. K. Shah: None. A. Dehdashti: None. J. Katz: None. H. Woo: None.

Introduction The Woven EndoBridge (WEB) device, an intrasaccular flow-diverter, was recently approved by the FDA to treat wide-neck bifurcation aneurysms. Accurate sizing of the WEB device is of critical importance as it determines procedural safety and successful occlusion. Oversized devices can protrude into the vessel lumen and lead to thromboembolic events, while undersized devices result in inadequate aneurysm occlusion. Conventionally, size selection of the WEB device is based on measurements of the fundus height and neck width on 3D rotational angiography. However, even multiple, orthogonal linear measurements incompletely describe the three-dimensional morphology of intracranial aneurysms and may mislead size selection of the WEB. An alternative method is volume-based segmentation, minimizing measurement error. The aim of this study was to assess the ability of auto-segmented aneurysm volume to assist in appropriate WEB size selection. Materials and Methods All patients with an intracranial aneurysm treated with the WEB SL or WEB SLS device between March 2019 and August 2019 were identified for this retrospective study. Aneurysm volumes were determined by using a three-dimensional volume segmentation software on an independent Syngo workstation (Siemens Healthineers AG). Pearson correlation coefficients were calculated for aneurysm auto-segmented volumes and WEB volumes, as well as for aneurysm height × width and WEB height × width at the time of initial treatment. Patients underwent follow-up angiography at least 6 months after embolization. Results Thirty-three aneurysms were evaluated by 3D rotational angiography. By volume, the largest aneurysm was 916.4 mm3, and the smallest was 14.0 mm3, with a median volume of 84.7 mm3. The smallest WEB device used was 4 × 2.6 SLS and the largest WEB device was 11 × 8 SL. The correlation with WEB size was larger for auto-segmented aneurysm volumes (r=0.979) compared to height × width (r=0.867). Using Fisher r-to-z transformations, we found the difference between the two correlations to be statistically significant (p=0.0007). Out of the patients who have undergone follow-up angiography thus far, 91% (10/11) have achieved adequate aneurysm occlusion (complete occlusion or residual neck). Conclusion Aneurysm volumes are highly correlated with WEB volumes, with auto-segmentation volumes displaying statistically significant difference against conventional height by width measurements. These results suggest that the WEB device is more accurately sized using auto-segmented aneurysm volumetric measurements rather than height and width measurements, which may improve long-term occlusion rates. Disclosures K. Shah: None. T. White: None. I. Teron: None. A. Dehdashti: None. J. Katz: None. H. Woo: None.

Introduction The Woven EndoBridge (WEB) is an intra-saccular flow-diverting device that is rapidly becoming popular in the treatment of wide-neck bifurcation aneurysms. However, several challenges remain, such as device compression, incomplete occlusion, and thromboembolic complications. Changes in intra-aneurysmal flow after the use of the WEB are not well understood and may be important in the performance of the device for aneurysm occlusion. The aim of this study was to characterize the degree of immediate aneurysm occlusion using color-coded quantitative digital subtraction angiography (DSA) after treatment with the WEB. Materials and Methods We retrospectively reviewed records of 34 patients treated with the WEB between March 2019 and February 2020. Eight patients were excluded from analysis for the use of a concurrent stent or intra-luminal flow-diverter. Measurements of contrast transit times on DSA were calculated with syngo iFlow (Siemens Healthineers AG). Regions of interest were selected within the parent vessel immediately proximal to the aneurysm and within the aneurysm dome before and after treatment with WEB (figure 1). The ratio of aneurysm contrast transit time to parent vessel contrast transit time was obtained before WEB placement and immediately after WEB placement. Transit time ratios were also compared with pre- and post-Pipeline (PED) cases matched for aneurysm size. Results Out of 26 aneurysms, 24 aneurysms demonstrated an increase in contrast transit time after WEB placement (2.06 s, p Conclusions High rates of immediate aneurysm contrast stagnation can be achieved with use of the WEB. As a flow-diverting device, the WEB offers a greater degree of immediate aneurysm occlusion than the PED. iFlow analysis provides a quantitative measure of post-treatment effect and could represent a predictive tool for successful long-term occlusion. Disclosures K. Shah: None. T. White: None. J. Turpin: None. I. Teron: None. J. Katz: None. H. Woo: None.

Giant and large pituitary adenomas (PA) constitute a specific subset of PAs, with gross total resection (GTR) rates frequently not exceeding 50%. Both an anatomical inaccessibility and an inadequate tumor visualization are thought to play a role. This study analyzes risk factors for postoperative residuals after endoscopic transsphenoidal pituitary surgery for large and giant pituitary adenomas. A retrospective analysis of patients with giant and large PA operated between 2015 and 2018 was performed. Forty patients (13 females, 27 males) were included in the analysis (30 large and 10 giant PAs). The mean MRI follow-up time was 5.9 ± 6.54 months. Overall, GTR was achieved in 29 patients (72.5%), subtotal resection in 9 (22.5%), and the inconclusive result was in 2 (5%). Unexpected residuals represented 7 (77.7%) of all 9 residual tumors. The most frequent intraoperative factor associated with unexpected residual tumors was improper identification of residual tumor due to obstruction of view in 2 (28.5%) cases and inability to distinguish normal tissue from tumor in the other two (28.5%). Sub-analysis based on tumor size revealed that with large PAs, GTR was achieved in 25 (83.3%), STR in 4 (13.3%), and inconclusive in 1 (3.3%) patient. In patients with giant PAs, GTR was achieved in 4 (40%), STR in 5 (50%), and inconclusive in 1 (10%). Analysis of preoperative factors showed a significant association of residual tumors with larger suprasellar AP distance (p = 0.041), retrosellar extension (p = 0.007), and higher Zurich Score (p = 0.029). Large and giant PAs are challenging lesions with high subtotal resection rates. Suprasellar AP distance, retrosellar extension, and higher Zurich Score seem to be significant predictors of degree of resection in these tumors. Improving the intraoperative ability to distinguish tumor from a normal tissue might further decrease the number of unexpected residuals.