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OBJECTIVE Brain arteriovenous malformations (bAVMs) most commonly present with rupture and intraparenchymal hemorrhage. In rare cases, the hemorrhage is large enough to cause clinical herniation or intractable intracranial hypertension. Patients in these cases require emergent surgical decompression as a life-saving measure. The surgeon must decide whether to perform concurrent or delayed resection of the bAVM. Theoretical benefits to concurrent resection include a favorable operative corridor created by the hematoma, avoiding a second surgery, and more rapid recovery and rehabilitation. The objective of this study was to compare the clinical and surgical outcomes of patients who had undergone concurrent emergent decompression and bAVM resection with those of patients who had undergone delayed bAVM resection. METHODS The authors conducted a 15-year retrospective review of consecutive patients who had undergone microsurgical resection of a ruptured bAVM at their institution. Patients presenting in clinical herniation or with intractable intracranial hypertension were included and grouped according to the timing of bAVM resection: concurrent with decompression (hyperacute group) or separate resection surgery after decompression (delayed group). Demographic and clinical characteristics were recorded. Groups were compared in terms of the primary outcomes of hospital and intensive care unit (ICU) lengths of stay (LOSs). Secondary outcomes included complete obliteration (CO), Glasgow Coma Scale score, and modified Rankin Scale score at discharge and at the most recent follow-up. RESULTS A total of 35/269 reviewed patients met study inclusion criteria; 18 underwent concurrent decompression and resection (hyperacute group) and 17 patients underwent emergent decompression only with later resection of the bAVM (delayed group). Hyperacute and delayed groups differed only in the proportion that underwent preresection endovascular embolization (16.7% vs 76.5%, respectively; p < 0.05). There was no significant difference between the hyperacute and delayed groups in hospital LOS (26.1 vs 33.2 days, respectively; p = 0.93) or ICU LOS (10.6 vs 16.1 days, respectively; p = 0.69). Rates of CO were also comparable (78% vs 88%, respectively; p > 0.99). Medical complications were similar in the two groups (33% hyperacute vs 41% delayed, p > 0.99). Short-term clinical outcomes were better for the delayed group based on mRS score at discharge (4.2 vs 3.2, p < 0.05); however, long-term outcomes were similar between the groups. CONCLUSIONS Ruptured bAVM rarely presents in clinical herniation requiring surgical decompression and hematoma evacuation. Concurrent surgical decompression and resection of a ruptured bAVM can be performed on low-grade lesions without compromising LOS or long-term functional outcome; however, the surgeon may encounter a more challenging surgical environment.

OBJECTIVE There is a reported elevated risk of cerebral aneurysms in patients with intracranial dural arteriovenous fistulas (dAVFs). However, the natural history, rate of spontaneous regression, and ideal treatment regimen are not well characterized. In this study, the authors aimed to describe the characteristics of patients with dAVFs and intracranial aneurysms and propose a classification system. METHODS The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database from 12 centers was retrospectively reviewed. Analysis was performed to compare dAVF patients with (dAVF+ cohort) and without (dAVF-only cohort) concomitant aneurysm. Aneurysms were categorized based on location as a dAVF flow-related aneurysm (FRA) or a dAVF non–flow-related aneurysm (NFRA), with further classification as extra- or intradural. Patients with traumatic pseudoaneurysms or aneurysms with associated arteriovenous malformations were excluded from the analysis. Patient demographics, dAVF anatomical information, aneurysm information, and follow-up data were collected. RESULTS Of the 1077 patients, 1043 were eligible for inclusion, comprising 978 (93.8%) and 65 (6.2%) in the dAVF-only and dAVF+ cohorts, respectively. There were 96 aneurysms in the dAVF+ cohort; 10 patients (1%) harbored 12 FRAs, and 55 patients (5.3%) harbored 84 NFRAs. Dural AVF+ patients had higher rates of smoking (59.3% vs 35.2%, p < 0.001) and illicit drug use (5.8% vs 1.5%, p = 0.02). Sixteen dAVF+ patients (24.6%) presented with aneurysm rupture, which represented 16.7% of the total aneurysms. One patient (1.5%) had aneurysm rupture during follow-up. Patients with dAVF+ were more likely to have a dAVF located in nonconventional locations, less likely to have arterial supply to the dAVF from external carotid artery branches, and more likely to have supply from pial branches. Rates of cortical venous drainage and Borden type distributions were comparable between cohorts. A minority (12.5%) of aneurysms were FRAs. The majority of the aneurysms underwent treatment via either endovascular (36.5%) or microsurgical (15.6%) technique. A small proportion of aneurysms managed conservatively either with or without dAVF treatment spontaneously regressed (6.2%). CONCLUSIONS Patients with dAVF have a similar risk of harboring a concomitant intracranial aneurysm unrelated to the dAVF (5.3%) compared with the general population (approximately 2%–5%) and a rare risk (0.9%) of harboring an FRA. Only 50% of FRAs are intradural. Dural AVF+ patients have differences in dAVF angioarchitecture. A subset of dAVF+ patients harbor FRAs that may regress after dAVF treatment.

Objective Clopidogrel is a commonly used antiplatelet agent for the prevention of thromboembolic complications following neuroendovascular procedures, but anecdotal data have raised concern for the possibility that clopidogrel may induce severe, intolerable fatigue. The purpose of this study is to systematically investigate this phenomenon. Methods We performed a dual-institution, 9-year, retrospective study of patients undergoing clopidogrel therapy for neuroendovascular procedures. Patients were included only if their response to clopidogrel was assessed by platelet function testing using the VerifyNow P2Y12 (VNP) assay. Hyperresponse to clopidogrel was defined as P2Y12 reaction units ≤60. Patients were considered to have had clopidogrel-induced severe fatigue if the onset of symptoms followed the initiation of clopidogrel therapy; symptoms improved following a reduction in the dose of clopidogrel; and symptoms could not be attributed to any other medical explanation. Results Data were collected on 349 patients. Five patients (1.4%) met criteria for clopidogrel-induced severe fatigue. All 5 patients were female, ages 39–68. VNP assessments obtained while patients were symptomatic revealed hyperresponse to clopidogrel (0–22 P2Y12 reaction units). Symptoms improved in all 5 patients when the dose of clopidogrel was reduced by half. Notably, 30% of patients (n = 103) demonstrated a hyperresponse to clopidogrel on at least 1 VNP assessment, but 98 of these patients did not suffer from severe fatigue. Conclusions A syndrome of severe fatigue and other constitutional symptoms is a rare but clinically significant side effect of hyperresponse to clopidogrel in patients undergoing neuroendovasular intervention.

OBJECTIVE Cranial dural arteriovenous fistulas (dAVFs) are often treated with endovascular therapy, but occasionally a multimodality approach including surgery and/or radiosurgery is utilized. Recurrence after an initial angiographic cure has been reported, with estimated rates ranging from 2% to 14.3%, but few risk factors have been identified. The objective of this study was to identify risk factors associated with recurrence of dAVF after putative cure. METHODS The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) data were retrospectively reviewed. All patients with angiographic cure after treatment and subsequent angiographic follow-up were included. The primary outcome was recurrence, with risk factor analysis. Secondary outcomes included clinical outcomes, morbidity, and mortality associated with recurrence. Risk factor analysis was performed comparing the group of patients who experienced recurrence with those with durable cure (regardless of multiple recurrences). Time-to-event analysis was performed using all collective recurrence events (multiple per patients in some cases). RESULTS Of the 1077 patients included in the primary CONDOR data set, 457 met inclusion criteria. A total of 32 patients (7%) experienced 34 events of recurrence at a mean of 368.7 days (median 192 days). The recurrence rate was 4.5% overall. Kaplan-Meier analysis predicted long-term recurrence rates approaching 11% at 3 years. Grade III dAVFs treated with endovascular therapy were statistically significantly more likely to experience recurrence than those treated surgically (13.3% vs 0%, p = 0.0001). Tentorial location, cortical venous drainage, and deep cerebral venous drainage were all risk factors for recurrence. Endovascular intervention and radiosurgery were associated with recurrence. Six recurrences were symptomatic, including 2 with hemorrhage, 3 with nonhemorrhagic neurological deficit, and 1 with progressive flow-related symptoms (decreased vision). CONCLUSIONS Recurrence of dAVFs after putative cure can occur after endovascular treatment. Risk factors include tentorial location, cortical venous drainage, and deep cerebral drainage. Multimodality therapy can be used to achieve cure after recurrence. A delayed long-term angiographic evaluation (at least 1 year from cure) may be warranted, especially in cases with risk factors for recurrence.

OBJECTIVE Cranial dural arteriovenous fistulas (dAVFs) are rare lesions, hampering efforts to understand them and improve their care. To address this challenge, investigators with an established record of dAVF investigation formed an international, multicenter consortium aimed at better elucidating dAVF pathophysiology, imaging characteristics, natural history, and patient outcomes. This report describes the design of the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) and includes characterization of the 1077-patient cohort. METHODS Potential collaborators with established interest in the field were identified via systematic review of the literature. To ensure uniformity of data collection, a quality control process was instituted. Data were retrospectively obtained. RESULTS CONDOR comprises 14 centers in the United States, the United Kingdom, the Netherlands, and Japan that have pooled their data from 1077 dAVF patients seen between 1990 and 2017. The cohort includes 359 patients (33%) with Borden type I dAVFs, 175 (16%) with Borden type II fistulas, and 529 (49%) with Borden type III fistulas. Overall, 852 patients (79%) presented with fistula-related symptoms: 427 (40%) presented with nonaggressive symptoms such as tinnitus or orbital phenomena, 258 (24%) presented with intracranial hemorrhage, and 167 (16%) presented with nonhemorrhagic neurological deficits. A smaller proportion (224 patients, 21%), whose dAVFs were discovered incidentally, were asymptomatic. Many patients (85%, 911/1077) underwent treatment via endovascular embolization (55%, 587/1077), surgery (10%, 103/1077), radiosurgery (3%, 36/1077), or multimodal therapy (17%, 184/1077). The overall angiographic cure rate was 83% (758/911 treated), and treatment-related permanent neurological morbidity was 2% (27/1467 total procedures). The median time from diagnosis to follow-up was 380 days (IQR 120–1038.5 days). CONCLUSIONS With more than 1000 patients, the CONDOR registry represents the largest registry of cranial dAVF patient data in the world. These unique, well-annotated data will enable multiple future analyses to be performed to better understand dAVFs and their management.

OBJECTIVE Current evidence suggests that intracranial dural arteriovenous fistulas (dAVFs) without cortical venous drainage (CVD) have a benign clinical course. However, no large study has evaluated the safety and efficacy of current treatments and their impact over the natural history of dAVFs without CVD. METHODS The authors conducted an analysis of the retrospectively collected multicenter Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database. Patient demographics and presenting symptoms, angiographic features of the dAVFs, and treatment outcomes of patients with Borden type I dAVFs were reviewed. Clinical and radiological follow-up information was assessed to determine rates of new intracranial hemorrhage (ICH) or nonhemorrhagic neurological deficit (NHND), worsening of venous hyperdynamic symptoms (VHSs), angiographic recurrence, and progression or spontaneous regression of dAVFs over time. RESULTS A total of 342 patients/Borden type I dAVFs were identified. The mean patient age was 58.1 ± 15.6 years, and 62% were women. The mean follow-up time was 37.7 ± 54.3 months. Of 230 (67.3%) treated dAVFs, 178 (77%) underwent mainly endovascular embolization, 11 (4.7%) radiosurgery alone, and 4 (1.7%) open surgery as the primary modality. After the first embolization, most dAVFs (47.2%) achieved only partial reduction in early venous filling. Multiple complementary interventions increased complete obliteration rates from 37.9% after first embolization to 46.7% after two or more embolizations, and 55.2% after combined radiosurgery and open surgery. Immediate postprocedural complications occurred in 35 dAVFs (15.2%) and 6 (2.6%) with permanent sequelae. Of 127 completely obliterated dAVFs by any therapeutic modality, 2 (1.6%) showed angiographic recurrence/recanalization at a mean of 34.2 months after treatment. Progression to Borden-Shucart type II or III was documented in 2.2% of patients and subsequent development of a new dAVF in 1.6%. Partial spontaneous regression was found in 22 (21.4%) of 103 nontreated dAVFs. Multivariate Cox regression analysis demonstrated that older age, NHND, or severe venous-hyperdynamic symptoms at presentation and infratentorial location were associated with worse prognosis. Kaplan-Meier curves showed no significant difference for stable/improved symptoms survival probability in treated versus nontreated dAVFs. However, estimated survival times showed better trends for treated dAVFs compared with nontreated dAVFs (288.1 months vs 151.1 months, log-rank p = 0.28). This difference was statistically significant for treated dAVFs with 100% occlusion (394 months, log-rank p < 0.001). CONCLUSIONS Current therapeutic modalities for management of dAVFs without CVD may provide better symptom control when complete angiographic occlusion is achieved.

BackgroundThe transcirculation approach (TCA) for stent-assisted coiling (SAC) of intracranial aneurysms may be useful for certain wide-neck bifurcation aneurysms as well as those with acute-angle efferent branches.ObjectiveTo describe a multicenter experience using the TCA for SAC.MethodsA multicenter, retrospective study (2016–2020) of aneurysm treatment using SAC via the TCA. Angiographic outcome was scored using the Raymond Scale (adequate occlusion 1 and 2), and clinical outcome was scored using a modified Rankin Scale (good outcome 0–2)ResultsTwenty-nine patients with 29 aneurysms were included (62.1% female; average age 61; 89.7% unruptured; 13.8% previously treated; average dome size 6.4 mm; average neck 4.4 mm). Aneurysm locations included internal carotid artery–fetal posterior cerebral artery (n=4), internal carotid artery terminus (n=4), anterior communicating artery (n=8), vertebral artery–posterior inferior cerebellar artery (n=2), and basilar tip (n=11). The TCA used communicating arteries (93.1%; average 1.6 mm), intermediate catheters (51.7%), jailing technique (62.1%), and staged procedures (10.3%). The most common stent was the Neuroform Atlas (Stryker; 69%). Immediate adequate occlusion was obtained in 75.9%, and five patients with inadequate occlusion progressed to adequate occlusion at follow-up. One (3.4%) procedural complication occurred: a watershed stroke in the setting of baseline four-vessel extracranial disease. Two patients had a poor outcome unrelated to the TCA. The majority of patients (86.4%) had a good clinical outcome. One case of in-stent stenosis due to non-compliance with medication was seen, which resolved with medication resumption.ConclusionsThe TCA for SAC can be performed for a variety of aneurysms with a low complication rate and good clinical outcomes.

BACKGROUND AND PURPOSE: The Neuroform Atlas is a new microstent to assist coil embolization of intracranial aneurysms that recently gained FDA approval. We present a postmarket multicenter analysis of the Neuroform Atlas stent. MATERIALS AND METHODS: On the basis of retrospective chart review from 11 academic centers, we analyzed patients treated with the Neuroform Atlas after FDA exemption from January 2018 to June 2019. Clinical and radiologic parameters included patient demographics, aneurysm characteristics, stent parameters, complications, and outcomes at discharge and last follow-up. RESULTS: Overall, 128 aneurysms in 128 patients (median age, 62 years) were treated with 138 stents. Risk factors included smoking (59.4%), multiple aneurysms (27.3%), and family history of aneurysms (16.4%). Most patients were treated electively (93.7%), and 8 (6.3%) underwent treatment within 2 weeks of subarachnoid hemorrhage. Previous aneurysm treatment failure was present in 21% of cases. Wide-neck aneurysms (80.5%), small aneurysm size (

BackgroundInfection from the SARS-CoV-2 virus has led to the COVID-19 pandemic. Given the large number of patients affected, healthcare personnel and facility resources are stretched to the limit; however, the need for urgent and emergent neurosurgical care continues. This article describes best practices when performing neurosurgical procedures on patients with COVID-19 based on multi-institutional experiences.MethodsWe assembled neurosurgical practitioners from 13 different health systems from across the USA, including those in hot spots, to describe their practices in managing neurosurgical emergencies within the COVID-19 environment.ResultsPatients presenting with neurosurgical emergencies should be considered as persons under investigation (PUI) and thus maximal personal protective equipment (PPE) should be donned during interaction and transfer. Intubations and extubations should be done with only anesthesia staff donning maximal PPE in a negative pressure environment. Operating room (OR) staff should enter the room once the air has been cleared of particulate matter. Certain OR suites should be designated as covid ORs, thus allowing for all neurosurgical cases on covid/PUI patients to be performed in these rooms, which will require a terminal clean post procedure. Each COVID OR suite should be attached to an anteroom which is a negative pressure room with a HEPA filter, thus allowing for donning and doffing of PPE without risking contamination of clean areas.ConclusionBased on a multi-institutional collaborative effort, we describe best practices when providing neurosurgical treatment for patients with COVID-19 in order to optimize clinical care and minimize the exposure of patients and staff.

Background and Purpose: Dural arteriovenous fistulae can present with hemorrhage, but there remains a paucity of data regarding subsequent outcomes. We sought to use the CONDOR (Consortium for Dural Arteriovenous Fistula Outcomes Research), a multi-institutional registry, to characterize the morbidity and mortality of dural arteriovenous fistula–related hemorrhage. Methods: A retrospective review of patients in CONDOR who presented with dural arteriovenous fistula–related hemorrhage was performed. Patient characteristics, clinical follow-up, and radiographic details were analyzed for associations with poor outcome (defined as modified Rankin Scale score ≥3). Results: The CONDOR dataset yielded 262 patients with incident hemorrhage, with median follow-up of 1.4 years. Poor outcome was observed in 17.0% (95% CI, 12.3%–21.7%) at follow-up, including a 3.6% (95% CI, 1.3%–6.0%) mortality. Age and anticoagulant use were associated with poor outcome on multivariable analysis (odds ratio, 1.04, odds ratio, 5.1 respectively). Subtype of hemorrhage and venous shunting pattern of the lesion did not affect outcome significantly. Conclusions: Within the CONDOR registry, dural arteriovenous fistula–related hemorrhage was associated with a relatively lower morbidity and mortality than published outcomes from other arterialized cerebrovascular lesions but still at clinically consequential rates.

Flow-diverting stents (FDS) are used to treat cerebral aneurysms. They promote the formation of a stable thrombus within the aneurysmal sac and, if successful, isolate the aneurysmal dome from mechanical stresses to prevent rupture. Platelet activation, a mechanism necessary for thrombus formation, is known to respond to biomechanical stimuli, particularly to the platelets’ residence time and shear stress exposure. Currently, there is no reliable method for predicting FDS treatment outcomes, either a priori or after the procedure. Eulerian computational fluid dynamic (CFD) studies of aneurysmal flow have searched for predictors of endovascular treatment outcome; however, the hemodynamics of thrombus formation cannot be fully understood without considering the platelets’ trajectories and their mechanics-triggered activation. Lagrangian analysis of the fluid mechanics in the aneurysmal vasculature provides novel metrics by tracking the platelets’ residence time (RT) and shear history (SH). Eulerian and Lagrangian parameters are compared for 19 patient-specific cases, both pre- and post-treatment, to assess the degree of change caused by the FDS and subsequent treatment efficacy.

BackgroundUse of the radial artery as an access site for neurointerventional procedures is gaining popularity after several studies in interventional cardiology have demonstrated superior patient safety, decreased length of stay, and patient preference compared with femoral artery access. The transradial approach has yet to be characterized for intraoperative cerebral angiography.ObjectiveTo report a multicenter experience on the use of radial artery access in intraoperative cerebral angiography, including case series and discussion of technical nuances.Methods27 patients underwent attempted transradial cerebral angiography betweenMay 2017 and May 2019. Data were collected regarding technique, patient positioning, vessels selected, technical success rate, and access site complications.Results24 of the 27 patients (88.8%) underwent successful transradial intraoperative cerebral angiography. 18 patients (66.7%) were positioned supine, 6 patients (22.2%) were positioned prone, 1 patient (3.7%) was positioned lateral, and 2 patients (7.4%) were positioned three-quarters prone. A total of 31 vessels were selected including 13 right carotid arteries (8 common, 1 external, 4 internal), 11 left carotid arteries (9 common and 2 internal), and 6 vertebral arteries (5 right and 1 left). Two patients (7.4%) required conversion to femoral access in order to complete the intraoperative angiogram (1 due to arterial vasospasm and 1 due to inadvertent venous catheterization). One procedure (3.7%) was aborted because of inability to obtain the appropriate fluoroscopic views due to patient positioning. No patient experienced stroke, arterial dissection, or access site complication.ConclusionsTransradial intraoperative cerebral angiography is safe and feasible with potential for improved operating room workflow ergonomics, faster patient mobility in the postoperative period, and reduced costs.

BackgroundPediatric acute ischemic stroke with underlying large vessel occlusion is a rare disease with significant morbidity and mortality. There is a paucity of data about the safety and outcomes of endovascular thrombectomy in these cases, especially with modern devices.MethodsWe conducted a retrospective review of all pediatric stroke patients who underwent endovascular thrombectomy in nine US tertiary centers between 2008 and 2017.ResultsNineteen patients (63.2% male) with a mean (SD) age of 10.9(6) years and weight 44.6 (30.8) kg were included. Mean (SD) NIH Stroke Scale (NIHSS) score at presentation was 13.9 (5.7). CT-based assessment was obtained in 88.2% of the patients and 58.8% of the patients had perfusion-based assessment. All procedures were performed via the transfemoral approach. The first-pass device was stentriever in 52.6% of cases and aspiration in 36.8%. Successful revascularization was achieved in 89.5% of the patients after a mean (SD) of 2.2 (1.5) passes, with a mean (SD) groin puncture to recanalization time of 48.7 (37.3) min (median 41.5). The mean (SD) reduction in NIHSS from admission to discharge was 10.2 (6.2). A good neurological outcome was achieved in 89.5% of the patients. One patient had post-revascularization seizure, but no other procedural complications or mortality occurred.ConclusionsEndovascular thrombectomy is safe and feasible in selected pediatric patients. Technical and neurological outcomes were comparable to adult literature with no safety concerns with the use of standard adult devices in patients as young as 18 months. This large series adds to the growing literature but further studies are warranted.

International audience; Perianeurysmal hemodynamics play a vital role in the initiation, growth and rupture of intracranial aneurysms. In vitro investigations of aneurysmal hemodynamics are helpful to visualize and measure blood flow, and aiding surgical planning approaches. Improving in vitro model creation can improve the feasibility and accuracy of hemodynamic investigations and surgical planning, improving clinical value. In this study, in vitro models were created from three-dimensional rotational angiography (3DRA) of six patients harboring intracranial aneurysms using a multi-step process involving 3D printing, index of refraction matching and silicone casting that renders the models transparent for flow visualization. Each model was treated with the same commercially-available, patient-specific, endovascular devices (coils and/or stents). All models were scanned by synchrotron X-ray microtomography to obtain high-resolution imaging of the vessel lumen, aneurysmal sac and endovascular devices. Dimensional accuracy was compared by quantifying the differences between the microtomographic reconstructions of the fabricated phantoms and the original 3DRA obtained during patient treatment. True-scale in vitro flow phantoms were successfully created for all six patients. Optical transparency was verified by using an index of refraction matched working fluid that replicated the mechanical behavior of blood. Synchrotron imaging of vessel lumen, aneurysmal sac and endovascular devices was successfully obtained, and dimensional errors were found to be O(100 μm). The creation of dimensionally-accurate, optically-transparent flow phantoms of patient-specific intracranial aneurysms is feasible using 3D printing technology. Such models may enable in vitro investigations of aneurysmal hemodynamics to aid in treatment planning and outcome prediction to devise optimal patient-specific neurointerventional strategies.

BackgroundAlthough the liquid embolic agent, Onyx, is often the preferred embolic treatment for cerebral dural arteriovenous fistulas (DAVFs), there have only been a limited number of single-center studies to evaluate its performance.ObjectiveTo carry out a multicenter study to determine the predictors of complications, obliteration, and functional outcomes associated with primary Onyx embolization of DAVFs.MethodsFrom the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database, we identified patients who were treated for DAVF with Onyx-only embolization as the primary treatment between 2000 and 2013. Obliteration rate after initial embolization was determined based on the final angiographic run. Factors predictive of complete obliteration, complications, and functional independence were evaluated with multivariate logistic regression models.ResultsA total 146 patients with DAVFs were primarily embolized with Onyx. Mean follow-up was 29 months (range 0–129 months). Complete obliteration was achieved in 80 (55%) patients after initial embolization. Major cerebral complications occurred in six patients (4.1%). At last follow-up, 84% patients were functionally independent. Presence of flow symptoms, age over 65, presence of an occipital artery feeder, and preprocedural home anticoagulation use were predictive of non-obliteration. The transverse-sigmoid sinus junction location was associated with fewer complications, whereas the tentorial location was predictive of poor functional outcomes.ConclusionsIn this multicenter study, we report satisfactory performance of Onyx as a primary DAVF embolic agent. The tentorium remains a more challenging location for DAVF embolization, whereas DAVFs located at the transverse-sigmoid sinus junction are associated with fewer complications.

Introduction Despite advancements in endovascular treatment of intracranial aneurysms, up to 30% recur and require additional treatment. Predicting outcomes after aneurysm treatment with flow-diverting stents (FDS) could impact treatment strategy and avoid unnecessary follow-up. Computational fluid dynamics (CFD) techniques have been used to simulate the effect of treatment on the intracranial aneurysm hemodynamics, and to quantify change in certain hemodynamics factors that can be associated with treatment success or failure. We use CFD simulations, based on aneurysm anatomy and patient-specific blood flow and pressure data, to study which hemodynamics factors are predictive of six-month treatment outcomes. Materials and Methods Twenty-four patients with n=25 unruptured intracranial aneurysms treated with FDS were included (Table 1). 3-dimensional rotational angiographic anatomy was used to create the computational model and intraoperative blood velocity and blood pressure measurements proximal to the aneurysm, obtained with an endovascular dual-sensor microwire, were used as boundary conditions for CFD simulations before and after FDS treatment. For post-treatment calculations, a virtual stent based on the Pipeline Flex Embolization Device was deployed into the CFD simulations. Hemodynamics factors within the aneurysm dome including flow into aneurysm (Q), wall shear stress (WSS), wall shear stress gradient (WSSG), viscous dissipation, oscillatory shear index (OSI), and relative residence time (RRT) were calculated before and after FDS placement. Aneurysm treatment was classified as success or failure based on six-month follow-up angiography. Hemodynamics changes between immediate post-treatment and pre-treatment simulations were associated to treatment outcomes. Results Marked reduction in Q, WSS, WSSG, and OSI were seen in most cases immediately after FDS treatment compared to the pretreatment values, indicative of the redirection of blood flow along the neck plane. Reduction of Q at peak systole and increase in RRT in the aneurysm dome were strong predictors of FDS treatment success. Further multivariate analysis of hemodynamic predictors of treatment outcome will be presented. Conclusion Patient-specific CFD simulations using intraoperative physiological velocity and pressure data have been performed pre- and immediately post-treatment. Hemodynamics factors have the potential to predict aneurysm treatment outcomes, making them valuable for neurointerventionalists to consider in treatment planning. Disclosures D. Lim: None. L. March: None. M. Barbour: None. H. Haughn: None. S. Levy: None. K. Prijoles: None. D. Bass: None. G. Barros: None. C. Kelly: None. F. Chassagne: None. A. Aliseda: None. M. Levitt: 1; C; Philips Volcano. L. Kim: None.

Introduction Early detection and treatment of intracranial aneurysms can prevent hemorrhagic stroke. However, treatment requires an invasive surgical procedure, which is potentially risky and costly. Risk quantification systems based on aneurysm size are imperfect since the majority of ruptured aneurysms are small, and no robust method exists for predicting an individual aneurysm’s likelihood of rupture. Endothelial cell (EC) genetics have been proposed to play a critical role in aneurysm risk. However, with the advent of endovascular treatment of aneurysms, there is a decline in the availability of biological tissue for research. Method We used a minimally-invasive endovascular EC collection technique to obtain aneurysmal ECs from aneurysm coils and access sheaths during endovascular treatment. Cells were collected from unruptured and ruptured aneurysms with low- and high-risk PHASES scores, as well as control arteries. After fluorescent-activated cell sorting (FACS), cytoplasmic mRNA from individual cells were extracted with SmartSeq Single CellTM and cDNA libraries were constructed for single cell RNA-Seq. Results Non-deployed endovascular coils and access sheaths from 15 patients (8 unruptured and 7 ruptured aneurysms) with a median PHASES score of 7, ranging from 3 – 11, were safely collected during endovascular treatment without adverse event. Cells were dissociated from the hardware and viable endothelial cells were identified by FACS with CD31 antibodies in 8 patients (5 unruptured and 3 ruptured aneurysms. Extracted RNA from single cells produced >500 pg of cDNA which was used for cDNA library construction and submitted for RNA sequencing. Conclusion Endovascular sampling of unruptured and ruptured aneurysm is safe and feasible. Despite the dissociation and FACS processes, endothelial cells were viable and produced sufficient cDNA at a single cell level for the construction of cDNA library for RNA sequencing. We envisage that this technique will greatly enhance the availability of cellular material for genetic study of cerebrovascular diseases. Disclosures C. Young: 1; C; AANS/CNS CV Section Robert J Dempsey Award 2019/2020, Bee Foundation Aneurysm Research Grant. S. Levy: None. A. Patel: None. D. Cooke: None. Y. Zheng: None. C. Mandrycky: None. C. Kelly: None. L. Kim: None. M. Levitt: None.

Introduction Spontaneous intracerebral hemorrhage (ICH) is a neurologically-devastating form of stroke. Minimally-invasive evacuation is increasingly investigated as a primary treatment. Secondary analyses of the MISTIE III (Minimally Invasive Surgery Plus Alteplase for Intracerebral Hemorrhage Evacuation) trial, which used stereotactic catheter drainage, demonstrated promising results among functional outcomes within the surgical arm. A sustained functional outcome advantage was found among patients with less than 15 mL residual clot volume or greater than 70% volume reduction. There is limited research on the effect of post-surgical ICH volumes on functional outcomes for patients specifically undergoing endoscopic evacuations. Objective Our primary objective is to study how the residual volume and percentage volume reduction of ICH after endoscopic evacuation affects the functional outcome of surgical patients. Methods We conducted a retrospective review of all endoscopic ICH evacuations performed between October 2016 and February 2020 by our institution’s cerebrovascular neurosurgery service. Demographics, comorbidities, ICH radiographic characteristics, cardiac status, intra-operative vital signs, medications, post-operative clinical course, and functional outcomes measured as mRS (modified Rankin Scale) were assessed The mRS was assessed at discharge, 30 days, and >90 days. Pre-operative and immediate post-operative CT scans were evaluated. ICH volumes before and after evacuation were manually calculated using the ABC/2 method. Results A total of 32 endoscopic evacuations among 31 patients were performed. The mean post-operative ICH volume was 15.3 mL (15.2), while the mean percentage volume reduction was 72.8% (24.4). There was a trend of lower post-operative ICH volumes correlating with lower mRS at discharge. Final data and analyses will be presented. Conclusion Lower post-operative residual clot volumes correlate with improved functional outcome at discharge in patients undergoing minimally-invasive endoscopic evacuation of ICH. Disclosures G. Barros: None. R. Kellogg: None. J. Keen: None. C. Kelly: None. A. Lele: 1; C; LifeCenter Northwest, Aqueduct Critical Care. L. Kim: 2; C; Microvention, Inc. 4; C; Spi Surgical, Inc. M. Levitt: 1; C; Stryker, Medtronic, Philips Volcano. 2; C; Metis Innovative. 4; C; Synchron, Eloupes, Cerebrotech.

Introduction Embolic coils are a preferred endovascular treatment technique for intracranial aneurysms, but approximately 34% of these treatments are unsuccessful, requiring re-treatment. To better understand why endovascular treatment fails, we used computational fluid dynamics (CFD) simulations to determine the changes in hemodynamics factors after coil embolization that were associated with treatment success versus those that led to failure. We incorporated patient-specific intravascular blood flow measurements as boundary conditions, which has been shown to improve simulation accuracy. Materials and Methods Adult patients presenting with unruptured intracranial aneurysms treated with coil embolization were enrolled. 3D-rotational angiograms taken before and immediately after treatment were used to create computational models of the patients’ vasculature. Intraoperative blood velocity and blood pressure measurements were obtained before and immediately after coil embolization by placing a dual-sensor microwire (ComboWire) in the proximal segment of the parent vessel. These measurements were incorporated as patient-specific boundary conditions for the CFD simulations to compute hemodynamics conditions before and after treatment. Hemodynamics variables including inflow rate (Q), wall shear stress (WSS), and wall shear stress gradient (WSSG) were calculated within each aneurysm. Treatment success or failure was determined by evaluating each patient’s most recent follow-up angiogram, and this outcome was then correlated to the changes in hemodynamics variables pre- and post-treatment. This statistical analysis aims to determine associations between immediate changes in post-treatment hemodynamics variables and treatment outcomes. Results Sixteen patients were included (table 1). Regardless of long-term treatment outcome, immediate post-treatment reductions were observed in Q, WSS and WSSG. Preliminary analyses suggest that an increase in shear stress at the aneurysm neck was associated with successful long-term outcome, representative of the significant redirection of blood flow velocity by the coil mass required to prevent aneurysm recanalization. Final multivariate analyses will be presented. Conclusion CFD simulations of aneurysm hemodynamics using patient-specific imaging and boundary conditions were performed in a large cohort of patients treated with coil embolization. Increases in neck plane shear and redirection of blood flow found immediately post-coil embolization have the potential to predict long-term treatment success. Disclosures S. Levy: None. L. Marsh: None. M. Barbour: None. K. Prijoles: None. D. Lim: None. H. Haughn: None. C. Kelly: None. F. Chassange: None. G. Barros: None. D. Bass: None. A. Aliseda: None. M. Levitt: 1; C; Philips Volcano. L. Kim: None.

Since the International Subarachnoid Aneurysm Trial,1 endovascular treatment has been the favored treatment for appropriate ruptured intracranial aneurysms. While our endovascular technology has advanced to allow us to treat the majority of intracranial aneurysms, simple coil embolization is still the most common modality. This video demonstrates the fundamentals of aneurysm catheterization and coiling for safe treatment. In addition, the set-up and devices are detailed. This video is to add to the library of basic techniques that will aid a large number of practitioners. This patient consented to endovascular treatment. The video demonstrates endovascular coil embolization of a posterior communicating artery aneurysm in a 76-yr-old female who presented with a subarachnoid hemorrhage. Image of biplane suite in video used courtesy of Siemens Medical Solutions USA, Inc. Illustration at 5:12 reprinted from Yasargil MG, et al, Microneurosurgery IV B, p. 9, Thieme, New York, 1995.

OBJECTIVE The risk-to-benefit profile of treating an unruptured high-grade dural arteriovenous fistula (dAVF) is not clearly defined. The aim of this multicenter retrospective cohort study was to compare the outcomes of different interventions with observation for unruptured high-grade dAVFs. METHODS The authors retrospectively reviewed dAVF patients from 12 institutions participating in the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR). Patients with unruptured high-grade (Borden type II or III) dAVFs were included and categorized into four groups (observation, embolization, surgery, and stereotactic radiosurgery [SRS]) based on the initial management. The primary outcome was defined as the modified Rankin Scale (mRS) score at final follow-up. Secondary outcomes were good outcome (mRS scores 0–2) at final follow-up, symptomatic improvement, all-cause mortality, and dAVF obliteration. The outcomes of each intervention group were compared against those of the observation group as a reference, with adjustment for differences in baseline characteristics. RESULTS The study included 415 dAVF patients, accounting for 29, 324, 43, and 19 in the observation, embolization, surgery, and SRS groups, respectively. The mean radiological and clinical follow-up durations were 21 and 25 months, respectively. Functional outcomes were similar for embolization, surgery, and SRS compared with observation. With observation as a reference, obliteration rates were higher after embolization (adjusted OR [aOR] 7.147, p = 0.010) and surgery (aOR 33.803, p < 0.001) and all-cause mortality was lower after embolization (imputed, aOR 0.171, p = 0.040). Hemorrhage rates per 1000 patient-years were 101 for observation versus 9, 22, and 0 for embolization (p = 0.022), surgery (p = 0.245), and SRS (p = 0.077), respectively. Nonhemorrhagic neurological deficit rates were similar between each intervention group versus observation. CONCLUSIONS Embolization and surgery for unruptured high-grade dAVFs afforded a greater likelihood of obliteration than did observation. Embolization also reduced the risk of death and dAVF-associated hemorrhage compared with conservative management over a modest follow-up period. These findings support embolization as the first-line treatment of choice for appropriately selected unruptured Borden type II and III dAVFs.

Background and Purpose: Given the benign natural history of intracranial low-grade dural arteriovenous fistulas (dAVFs), their routine treatment remains controversial. The aim of this study is to compare the outcomes of low-grade dAVF treatment to conservative management. Methods: We performed a retrospective review of dAVF patients derived from 12 institutions participating in the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR). Patients with low-grade (Borden I) dAVFs were included and categorized into treatment and observation cohorts. Primary outcome was defined as modified Rankin Scale (mRS) score at final follow-up. Secondary outcomes were rates of excellent (mRS 0-1) and good (mRS 0-2) functional outcomes, symptomatic improvement, mortality, and obliteration at final follow-up. Results: The treatment and observation cohorts comprised 230 and 112 patients, respectively. At last follow up, no difference in primary or secondary outcomes was observed between the two cohorts, with the exception of obliteration, which was higher in the treatment cohort (79.3% vs. 28.2%, p Conclusions: Low-grade dAVF treatment was not associated with increased functional disability compared to conservative management. Although higher obliteration rates were achieved in the treatment cohort, rates of symptomatic improvement were similar between the two cohorts. This study did not provide evidence to support the routine treatment of low-grade dAVFs.

As frequency of endovascular treatments for intracranial aneurysms increases, there is a growing need to understand the mechanisms for coil embolization failure. Computational fluid dynamics (CFD) modeling often simplifies modeling the endovascular coils as a homogeneous porous medium (PM), and focuses on the vascular wall endothelium, not considering the biomechanical environment of platelets. These assumptions limit the accuracy of computations for treatment predictions. We present a rigorous analysis using X-ray microtomographic imaging of the coils and a combination of Lagrangian (platelet) and Eulerian (endothelium) metrics. Four patient-specific, anatomically accurate in vitro flow phantoms of aneurysms are treated with the same patient-specific endovascular coils. Synchrotron tomography scans of the coil mass morphology are obtained. Aneurysmal hemodynamics are computationally simulated before and after coiling, using patient-specific velocity/pressure measurements. For each patient, we analyze the trajectories of thousands of platelets during several cardiac cycles, and calculate residence times (RTs) and shear exposure, relevant to thrombus formation. We quantify the inconsistencies of the PM approach, comparing them with coil-resolved (CR) simulations, showing the under- or overestimation of key hemodynamic metrics used to predict treatment outcomes. We fully characterize aneurysmal hemodynamics with converged statistics of platelet RT and shear stress history (SH), to augment the traditional wall shear stress (WSS) on the vascular endothelium. Incorporating microtomographic scans of coil morphology into hemodynamic analysis of coiled intracranial aneurysms, and augmenting traditional analysis with Lagrangian platelet metrics improves CFD predictions, and raises the potential for understanding and clinical translation of computational hemodynamics for intracranial aneurysm treatment outcomes.

The choice of anesthetic technique, general anesthesia (GA) versus Monitored Anesthesia Care, may impact the outcome of patients undergoing endovascular treatment of acute ischemic stroke (AIS). The aim of this study was to identify the factors associated with good discharge outcome in patients receiving GA for AIS.Electronic medical records of patients above 18 years old who underwent endovascular treatment of AIS under GA at a Comprehensive Stroke Center from 2010 to 2014 were reviewed. Good outcome was defined as discharge modified Rankin Score 0 to 2 and poor outcome as modified Rankin Score 3 to 6; logistic regression analysis was performed to examine the association between the clinical characteristics and the outcome.In total, 88 patients (56 males), aged 63±15 years with median National Institute of Health Stroke Scale (NIHSS) score 16 (range, 4 to 38) were included. Nineteen (22%) patients had good outcome and 78 (88%) had systolic blood pressure below the guideline recommended 140 mm Hg under GA. After adjusting for age and NIHSS score, the independent predictors of good discharge outcomes were higher maximum end-tidal carbon dioxide (odds ratio [OR], 1.14; confidence interval [CI], 1.02-1.28; P=0.02) and extubation after endovascular treatment (OR, 26.31; CI, 4.80-144.12; P0.0001). A secondary analysis was performed after excluding 25 patients emergently intubated in the Emergency Department for airway protection. In the logistic regression analysis controlling for age and NIHSS score, postprocedure extubation was still associated with higher odds of good outcomes (OR, 13.35; CI, 2.58-68.90; P=0.002).These findings indicate the importance of ventilation management and extubation after endovascular intervention under GA in patients with AIS.

Intraosseous hemangiomas of the maxillofacial region are rare lesions that constitute less than 1% of all osseous tumors. A review of the literature on intraosseous hemangiomas of the skull and facial bones showed a limited number of publications, much of which were largely limited to case reports. This case report summarizes the workup and surgical treatment of a 39-year-old woman with an intraosseous hemangioma of the left frontal bone. The histology, treatment, and literature are reviewed.

Background Different operative techniques are reported for the resection of brainstem cavernous malformations (BSCMs). The senior author has previously reported on a less-invasive technique of entering the brain stem with piecemeal removal of BSCMs, especially the deep-seated ones. Objective To present a larger series of these lesions, emphasizing the approach to the brain stem via case selection. We discuss the nuances of the less-invasive operative technique through case illustrations and intraoperative videos. Methods A retrospective review of 46 consecutive cases of BSCMs, with their clinical and radiographic data, was performed. Nine cases were selected to illustrate 7 different operative approaches, and discuss surgical nuances of the less-invasive technique unique to each. Results Postoperative morbidity, defined as an increase in modified Rankin Scale, was observed in 5 patients (10.9%). A residual BSCM was present in 2 patients (4.3%); both underwent reoperation to remove the remainder. At follow-up of 31.1 ± 27.8 mo, 3 patients experienced recurrence (6.5%). Overall, 65% of our patients improved, 20% stayed the same, and 11% worsened postsurgery. Two patients died, yielding a mortality of 4.3%. Conclusion Using the less-invasive resection technique for piecemeal BSCM removal, in appropriately selected patients, has yielded comparable to improved patient outcomes over existing large series. In our experience, lateral, anterolateral, and posterolateral approaches are favorable over direct midline (dorsal or ventral) approaches. A thorough understanding of brain-stem safe-entry zones, in conjunction with appropriate approach selection, is key to a good outcome in challenging cases.

Background Different operative techniques are reported for the resection of brainstem cavernous malformations (BSCMs). The senior author has previously reported on a less-invasive technique of entering the brain stem with piecemeal removal of BSCMs, especially the deep-seated ones. Objective To present a larger series of these lesions, emphasizing the approach to the brain stem via case selection. We discuss the nuances of the less-invasive operative technique through case illustrations and intraoperative videos. Methods A retrospective review of 46 consecutive cases of BSCMs, with their clinical and radiographic data, was performed. Nine cases were selected to illustrate 7 different operative approaches, and discuss surgical nuances of the less-invasive technique unique to each. Results Postoperative morbidity, defined as an increase in modified Rankin Scale, was observed in 5 patients (10.9%). A residual BSCM was present in 2 patients (4.3%); both underwent reoperation to remove the remainder. At follow-up of 31.1 ± 27.8 mo, 3 patients experienced recurrence (6.5%). Overall, 65% of our patients improved, 20% stayed the same, and 11% worsened postsurgery. Two patients died, yielding a mortality of 4.3%. Conclusion Using the less-invasive resection technique for piecemeal BSCM removal, in appropriately selected patients, has yielded comparable to improved patient outcomes over existing large series. In our experience, lateral, anterolateral, and posterolateral approaches are favorable over direct midline (dorsal or ventral) approaches. A thorough understanding of brain-stem safe-entry zones, in conjunction with appropriate approach selection, is key to a good outcome in challenging cases.

ObjectiveTo evaluate the safety and effectiveness of the Flow Redirection Endoluminal Device (FRED) flow diverter in support of an application for Food and Drug Administration approval in the USA.Methods145 patients were enrolled in a prospective, single-arm multicenter trial. Patients with aneurysms of unfavorable morphology for traditional endovascular therapies (large, wide-necked, fusiform, etc) were included. The trial was designed to demonstrate non-inferiority in both safety and effectiveness, comparing trial results with performance goals (PGs) established from peer-reviewed published literature. The primary safety endpoint was death or major stroke (National Institutes of Health Stroke Scale score ≥4 points) within 30 days of the procedure, or any major ipsilateral stroke or neurological death within the first year. The primary effectiveness endpoint was complete occlusion of the target aneurysm with ≤50% stenosis of the parent artery at 12 months after treatment, and in which an alternative treatment of the target intracranial aneurysm had not been performed.Results145 patients underwent attempted placement of a FRED device, and one or more devices were placed in all 145 patients. 135/145 (93%) had a single device placed. Core laboratory adjudication deemed 106 (73.1%) of the aneurysms large or giant. A safety endpoint was experienced by 9/145 (6.2%) patients, successfully achieving the safety PG of 46% aneurysm occlusion was also achieved, with the effectiveness endpoint being met in 80/139 (57.6%)ConclusionAs compared with historically derived performance benchmarks, the FRED flow diverter is both safe and effective for the treatment of appropriately selected intracranial aneurysms.Clinical registration numberNCT01801007

Objective Spetzler-Martin grade 3 (SM3) lesions entail 4 distinct subtypes described based on size, eloquence, and deep venous drainage (3A–3D). The ideal management of each is contentious, and the results of A Randomized Trial of Unruptured Brain AVMs (ARUBA) introduced additional controversy and attention toward management strategies of unruptured brain arteriovenous malformations (bAVMs). Methods We retrospectively reviewed 114 patients with treated SM3 bAVMs, including both ruptured and unruptured lesions. Primary outcomes included modified Rankin score at most recent follow-up, angiographic cure, and permanent treatment-related complications (morbidity). Other outcomes included mortality, bAVM recurrence or rebleed, and transient treatment-related complications. We used univariate and multivariate modeling to determine whether any specific features were predictive of outcomes. For unruptured bAVMs, an “ARUBA eligible” subgroup analysis was performed. We also reviewed the literature on management of ruptured and unruptured SM3 bAVMs. Results Of the 114 identified SM3 bAVMs, 40% were unruptured. Most (43.5%) lesions in the unruptured group were type 3C, whereas most ruptured bAVMs (66.2%) were type 3A. Unruptured lesions were mostly managed with radiosurgery (47.8%) and ruptured ones with preoperative embolization and surgery (36.7%). Surgical intervention was predictive of angiographic cure in multivariate modeling, even after controlling for ≥2 years of follow-up, although associated with a slightly higher rate of morbidity. Focal neurological deficit was the only predictor of a worse (modified Rankin score ≥2) functional outcome in follow-up for unruptured bAVMs. For ruptured bAVMs, superficial and cerebellar locations were predictive of better outcomes in multivariate models, in the absence of a focal neurological deficit at presentation and new after surgery deficit. ARUBA SM3 bAVMs specifically underwent more embolization as a monotherapy and less microsurgical resection than the present series. Conclusions In spite of a heterogeneous array of angioarchitectural and anatomic features, SM3 bAVMs can be treated safely and effectively with surgery and radiosurgery either without or with pretreatment embolization. Ruptured lesions are more often type 3A, with smaller nidus, deep brain location, and deep venous drainage. Focal neurological deficit predicts worse clinical outcomes. Contemporary multimodality management of SM3 bAVMs is not adequately represented in the results of ARUBA, likely due to differences in treatment strategies.

Background High-risk components of brain arteriovenous malformations (BAVMs) can be targeted to reduce the risk of lesion rupture. Objective To evaluate targeted embolization of aneurysms against other means of treatment with a case-control analysis; we previously investigated this approach associated with BAVMs. Methods Retrospective analysis of patients with BAVMs was performed, identifying patients treated with intention to occlude only an aneurysm associated with a BAVM. For each targeted aneurysm embolization (TAE) patient identified, 4 control patients were randomly selected, controlling for rupture status, age, and Spetzler-Martin plus Lawton-Young supplemental score. Analysis was performed to compare rates of adverse events (hemorrhage, new seizure, and death) between the 2 groups. Results Thirty-two patients met inclusion criteria, and 128 control patients were identified, out of 1103 patients treated during the study period. Thirty-four adverse events occurred (15 ruptures, 15 new seizures, and 11 deaths) during the follow-up period (mean 1157 d for the TAE cohort and 1036 d for the non-TAE cohort). Statistically lower associations were noted for the TAE group for any adverse event (hazard ratio 0.28, P = .037) and the composite outcome of hemorrhage or new seizure (hazard ratio 0.20, P = .029). Conclusion For BAVMs at high risk for surgical resection, TAE can be performed safely and effectively. Patients treated with TAE had better outcomes than matched patients undergoing other combinations of treatment. TAE can be considered for BAVMs with high operative risk prior to radiosurgery or when no other treatment options are available.

BACKGROUND Cerebral bypass has been an important tool in the treatment of complex intracranial aneurysms. The recent advent of flow-diverting stents (FDS) has expanded the capacity for endovascular arterial reconstruction. OBJECTIVE We investigated how the advent of FDS has impacted the application and outcomes of cerebral bypass in the treatment of intracranial aneurysms. METHODS We reviewed a consecutive series of cerebral bypasses during aneurysm surgery over the course of 10 years. FDS were in active use during the last 5 years of this series. We compared the clinical characteristics, surgical technique, and outcomes of patients who required cerebral bypass for aneurysm treatment during the preflow diversion era (PreFD) with those of the postflow diversion era (PostFD). RESULTS We treated 1061 aneurysms in the PreFD era (from July 2005 through June 2010) and 1348 in the PostFD era (from July 2010 through June 2015). Eighty-five PreFD patients (8%) and 45 PostFD patients (3%) were treated with cerebral bypass. PreFD patients had better baseline functional status compared to PostFD patients with average preoperative modified Rankin Scale score of 0.55 in PreFD and 1.18 in PostFD. CONCLUSION After the introduction of FDS, cerebral bypass was performed in a lower proportion of patients with aneurysms. Patients selected for bypass in the flow-diverter era had worse preoperative modified Rankin Scale scores indicating a greater complexity of the patients. Cerebral bypass in well-selected patients and revascularization remains an important technique in vascular neurosurgery. It is also useful as a rescue technique after failed FDS treatment of aneurysms.

Iatrogenic dissection of the internal carotid artery is a well-known complication that can occur during mechanical thrombectomy for acute stroke. The vast majority of these injuries are limited to the cervical segment, and only in exceptional circumstances do they require surgical intervention. In the present case, extension of the lesion into the petrous segment of the carotid artery resulted in an acute neurologic decline necessitating emergent endovascular repair. We discuss the nuances of managing an exceptionally rare presentation of this complication.

BackgroundDural arteriovenous fistulae (dAVFs) comprise 10–15% of all intracranial arteriovenous malformations. The goal of surgical or endovascular intervention is complete obliteration of the fistulous connection(s). In cases where dAVF venous drainage is separate from normal cortical drainage, transvenous embolization can provide fast and effective fistula obliteration.ObjectiveTo describe a new method of efficient transvenous embolization (the ‘dual microcatheter technique’) for the treatment of dAVFs.MethodsThree patients with dAVFs were treated using the dual microcatheter technique for transvenous embolization. Two microcatheters were placed in the distal aspect of the dAVF venous pouch, after which coil embolization reduced fistula flow, and liquid embolic agent injection with reflux into arterial feeders completed the obliteration of the fistula.ResultsLesion grade ranged from Borden–Shucart grades 2 through 3. In all cases, dAVF venous drainage was isolated from the normal cerebral venous drainage. Dual microcatheter transvenous embolization was successful in all patients, with non-target embolization and no new postoperative deficits. At the last follow-up, all three patients were symptom-free without evidence of radiographic recurrence.ConclusionsThe dual microcatheter technique of transvenous dAVF embolization is safe and feasible in cases where dAVF venous outflow is isolated from normal cerebral venous drainage.

OBJECTIVE Brain arteriovenous malformations (bAVMs) are rare in pediatric patients but represent the most common cause of hemorrhagic stroke in this population. Pediatric patients demonstrate superior outcomes in comparison with adult patients with similar lesions and presentations. Most studies of clinical outcomes of pediatric bAVMs use the modified Rankin Scale (mRS), despite a lack of validation in pediatric patients. METHODS The authors interviewed the parents of 26 pediatric patients who underwent multimodality bAVM treatment and administered the Pediatric Quality of Life Inventory (PedsQL)—a well-validated tool for pediatric outcomes that quantifies performance in a physical, emotional, social, and school domains. They also reviewed clinical information from the patients' medical charts. Statistical analysis was performed using a log-transformed t-test, the Mann-Whitney exact test, the Kruskal-Wallis test, and Spearman correlation. In addition, the literature was reviewed for prior reports of clinical outcome of pediatric cases of bAVM. RESULTS The average PedsQL health-related quality of life score was 71 ± 24, with an average age at diagnosis of 12.5 years and an average follow-up period of 6.8 years. Seventeen patients (65%) presented with hemorrhage and 4 (15%) with seizures. PedsQL scores correlated strongly and at a statistically significant level (p < 0.001) with mRS, Pediatric Overall Performance Category (POPC), Pediatric Cerebral Performance Category (PCPC), and Glasgow Outcome Scale scores. Multivariate modeling validated special education, corrective devices, and cure status as significant predictors of PedsQL scores. Statistically significant risk factors for undergoing placement of a ventriculoperitoneal shunt included lower Glasgow Coma Scale motor scores on admission (p = 0.042), cerebellar location (p = 0.046), and nidus volume (p = 0.017). Neither treatment modality nor location statistically affected clinical outcomes at follow-up. CONCLUSIONS There have been few studies of long-term clinical outcomes of bAVM in pediatric patients, and previously published studies have used conventional metrics that have been validated in the adult population, such as the mRS. Although these metrics can serve as reasonable surrogates, an accurate understanding of overall health-related quality of life is contingent on utilizing validated toolsets, such as the PedsQL.

Giant, partially-thrombosed basilar artery (BA) aneurysms are extraordinarily difficult to treat. Due to the high risk of rupture exclusion of these aneurysms from the circulation is imperative. In certain instances, direct clipping is unsuitable, and high-flow bypass and proximal parent vessel clip occlusion is required. We report a case of a recurrent partially-thrombosed giant BA apex aneurysm treated with endovascular stent-coiling through a previous radial artery bypass graft. Following the initial bypass and aneurysm trapping six years prior, the patient was neurologically stable until three months prior to admission when he developed new diplopia and left third nerve palsy. Imaging studies demonstrated interval enlargement of the thrombosed portion of the aneurysm and increased size in the filling portion of the aneurysm. In the present case, the existing radial artery bypass graft between left VA and left PCA permitted successful stent-assisted embolization of the recurrent BA aneurysm. To our knowledge, this is the first published case of endovascular stent-coiling of a BA aneurysm through a radial artery bypass graft. This novel technique can be a useful alternative for endovascular aneurysm treatment in these challenging lesions.

The technique of balloon-assisted tracking (BAT) has been demonstrated in transradial cardio-angiographic procedures. Using three commonly encountered clinical scenarios, we outline the technical details of BAT for managing peripheral and cerebral interventions with challenging vascular access. We describe methods used to overcome vasospasm, stenosis and vascular shelves during interventions for acute ischemic stroke, but these issues are not unique to neuroendovascular cases and the techniques can be applied across all endovascular interventions. We present three acute stroke interventions where anatomic challenges were overcome with the use of endovascular BAT. This article describes a novel application for BAT techniques in endovascular interventions to assist with access in peripheral, cervical and intracranial vessels. These methods can also be used to improve access during diagnostic cerebral angiography. BAT is a useful adjunct when navigating catheters through vasospasm, tortuous anatomy, vascular step-offs or intraluminal plaques.

Carotid cavernous fistulas (CCFs) are often a result of trauma, cavernous carotid artery aneurysm rupture, or arteriovenous fistulae. Although a proportion can be managed expectantly, CCFs that are under high flow can lead to rapid neurologic deterioration or visual loss requiring expeditious diagnosis and management. This chapter presents the case of a female patient who presented with subacute vision loss, chemosis, and proptosis and was treated for bilateral CCF using endovascular embolization. A strong understanding of the pathology and meticulous endovascular technique are necessary in deciding which endovascular approach and embolization agents to use in obliterating the fistula. Both transvenous and transarterial routes may be used. Legacy open intracranial methods exist for treating CCF, but are rarely needed now.

IntroductionEndovascular embolization of intracranial meningiomas is commonly used as an adjunct to surgical resection. We sought to describe the anatomic locations and vascular supplies of meningiomas to identify characteristics predictive of successful preoperative endovascular embolization.MethodsWe conducted a retrospective review of 139 meningioma cases receiving cerebral angiograms for possible preoperative endovascular embolization at our institution between December 2000 and March 2017. The extent of embolization, arterial supply, anatomic location, and procedural complications were recorded for each case. Univariate and multivariate analyses were performed to identify tumor characteristics that predicted successful embolization.ResultsOf the total meningioma patients undergoing preoperative angiography, 78% (108/139) were successfully embolized, with a 2.8% periprocedural complication rate (3/108). Within the subset of patients with successful embolization, 31% (33/108) achieved complete angiographic embolization. Significant multivariate predictors of embolization (either partial or complete) were convexity/parasagittal locations (OR 5.15, 95% CI 0.93 to 28.54, p=0.060), meningohypophyseal trunk (MHT, OR 4.65, 95% CI 1.63 to 13.23, p=0.004), middle meningeal artery (MMA, OR 10.89, 95% CI 3.43 to 34.64, pConclusionsTumor characteristics can be used to predict the likelihood of preoperative meningioma embolization. Parasagittal and convexity meningiomas, and those with APA supply, are most likely to achieve complete angiographic embolization.

The role of somatic genetic variants in the pathogenesis of intracranial-aneurysm formation is unknown. We identified a 23-year-old man with progressive, right-sided intracranial aneurysms, ipsilateral to an impressive cutaneous phenotype. The index individual underwent a series of genetic evaluations for known connective-tissue disorders, but the evaluations were unrevealing. Paired-sample exome sequencing between blood and fibroblasts derived from the diseased areas detected a single novel variant predicted to cause a p.Tyr562Cys (g.149505130T>C [GRCh37/hg19]; c.1685A>G) change within the platelet-derived growth factor receptor β gene (PDGFRB), a juxtamembrane-coding region. Variant-allele fractions ranged from 18.75% to 53.33% within histologically abnormal tissue, suggesting post-zygotic or somatic mosaicism. In an independent cohort of aneurysm specimens, we detected somatic-activating PDGFRB variants in the juxtamembrane domain or the kinase activation loop in 4/6 fusiform aneurysms (and 0/38 saccular aneurysms; Fisher’s exact test, p < 0.001). PDGFRB-variant, but not wild-type, patient cells were found to have overactive auto-phosphorylation with downstream activation of ERK, SRC, and AKT. The expression of discovered variants demonstrated non-ligand-dependent auto-phosphorylation, responsive to the kinase inhibitor sunitinib. Somatic gain-of-function variants in PDGFRB are a novel mechanism in the pathophysiology of fusiform cerebral aneurysms and suggest a potential role for targeted therapy with kinase inhibitors.

ObjectivesTo study the correlation between wall shear stress and endothelial cell expression in a patient-specific, three-dimensional (3D)-printed model of a cerebral aneurysm.Materials and methodsA 3D-printed model of a cerebral aneurysm was created from a patient’s angiogram. After populating the model with human endothelial cells, it was exposed to media under flow for 24 hours. Endothelial cell morphology was characterized in five regions of the 3D-printed model using confocal microscopy. Endothelial cells were then harvested from distinct regions of the 3D-printed model for mRNA collection and gene analysis via quantitative polymerase chain reaction (qPCR.) Cell morphology and mRNA measurement were correlated with computational fluid dynamics simulations.ResultsThe model was successfully populated with endothelial cells, which survived under flow for 24 hours. Endothelial morphology showed alignment with flow in the proximal and distal parent vessel and aneurysm neck, but disorganization in the aneurysm dome. Genetic analysis of endothelial mRNA expression in the aneurysm dome and distal parent vessel was compared with the proximal parent vessels. ADAMTS-1 and NOS3 were downregulated in the aneurysm dome, while GJA4 was upregulated in the distal parent vessel. Disorganized morphology and decreased ADAMTS-1 and NOS3 expression correlated with areas of substantially lower wall shear stress and wall shear stress gradient in computational fluid dynamics simulations.ConclusionsCreating 3D-printed models of patient-specific cerebral aneurysms populated with human endothelial cells is feasible. Analysis of these cells after exposure to flow demonstrates differences in both cell morphology and genetic expression, which correlate with areas of differential hemodynamic stress.

OBJECTIVEDelayed cerebral ischemia (DCI) is a significant contributor to poor outcomes after aneurysmal subarachnoid hemorrhage (aSAH). The neurotoxin 3-aminopropanal (3-AP) is upregulated in cerebral ischemia. This phase II clinical trial evaluated the efficacy of tiopronin in reducing CSF 3-AP levels in patients with aSAH.METHODSIn this prospective, randomized, double-blind, placebo-controlled, multicenter clinical trial, 60 patients were assigned to receive tiopronin or placebo in a 1:1 ratio. Treatment was commenced within 96 hours after aSAH onset, administered at a dose of 3 g daily, and continued until 14 days after aSAH or hospital discharge, whichever occurred earlier. The primary efficacy outcome was the CSF 3-AP level at 7 ± 1 days after aSAH.RESULTSOf the 60 enrolled patients, 29 (97%) and 27 (93%) in the tiopronin and placebo arms, respectively, received more than one dose of the study drug or placebo. At post-aSAH day 7 ± 1, CSF samples were available in 41% (n = 12/29) and 48% (n = 13/27) of patients in the tiopronin and placebo arms, respectively. No difference in CSF 3-AP levels at post-aSAH day 7 ± 1 was observed between the study arms (11 ± 12 nmol/mL vs 13 ± 18 nmol/mL; p = 0.766). Prespecified adverse events led to early treatment cessation for 4 patients in the tiopronin arm and 2 in the placebo arm.CONCLUSIONSThe power of this study was affected by missing data. Therefore, the authors could not establish or refute an effect of tiopronin on CSF 3-AP levels. Additional observational studies investigating the role of 3-AP as a biomarker for DCI may be warranted prior to its use as a molecular target in future clinical trials.Clinical trial registration no.: NCT01095731 (ClinicalTrials.gov)

Introduction: Subacute symptomatic neurological decline is a significant and preventable contributor to patient morbidity and mortality after aneurysmal subarachnoid hemorrhage (aSAH). 3-Aminopropanal (3-AP) is a potent neurotoxin that is upregulated in the setting of cerebral ischemia. Targeted neutralization has achieved a neuroprotective effect in preclinical models. This phase II trial evaluated the efficacy of Tiopronin administration in reducing 3-AP levels in patients with aSAH. Methods: We designed a prospective, randomized, double-blind, placebo-controlled clinical trial that was conducted in three centers in the United States. 60 patients were enrolled and assigned to receive Tiopronin or placebo in a 1:1 ratio from enrolment until the earlier to occur of post-bleed day 14 or hospital discharge. Patients received a total of 3 grams daily, in 3 divided doses. The primary efficacy endpoint was the change in serum and/or cerebrospinal fluid (CSF) 3-AP from enrolment to study drug discontinuation. Results: Of the 60 enrolled patients, 29 (97%) in the treatment arm and 27 (93%) in the control arm received more than one dose of the study drug. A greater relative reduction in serum 3-AP level was observed in the treatment arm (adj Beta=-0.689, 95% C.I.=-2.730, -0.008; p=0.049). This was most apparent, but did not reach significance, in patients with grade IV-V aSAH (adj Beta=-0.808; 95% C.I.=-3.872, 0.167; p=0.067). No difference in the change in CSF level was observed (adj Beta=0.048, 95% C.I.=-2.334, 2.589; p=0.903). Pre-specified adverse events led to early cessation of treatment for four patients in the treatment arm, and two in the control arm. Conclusion: Tiopronin attenuated the accumulation of serum 3-AP, providing the first translational evidence for the use of 3-AP antagonists in aSAH. Further investigation to evaluate for a dose-response relationship in Tiopronin’s ability to cross the blood-brain barrier is recommended.

OBJECTIVE: Identification of aneurysms at risk for rupture is important and challenging. We sought to evaluate if intracranial vessel wall (IVW) imaging characteristics of unruptured aneurysms correlate with clinical risk factors for rupture. METHODS: Patients with unruptured intracranial aneurysms were prospectively recruited and underwent a multi contrast 3D IVW protocol between April 6, 2016 and August 29, 2017. Two independent raters, blinded to aneurysm vulnerability, evaluated each aneurysm for wall enhancement, extent of enhancement in terms of the numbers of quadrants enhancing circumferentially, intensity of enhancement, and qualitative wall thinning. PHASES score was calculated for each aneurysm. Univariate logistic regression analysis was used to compare IVW characteristics between aneurysms at higher clinical risk for rupture (PHASES score > 3) and lower clinical risk for rupture (PHASES score ≤ 3). RESULTS: 45 patients with 65 unruptured aneurysms were analyzed; 38 aneurysms with PHASES score > 3 (58%) and 27 aneurysms with PHASES score ≤ 3 (42%). Aneurysms with PHASES score > 3 were more likely to demonstrate enhancement (42.1% vs 14.8%, p = 0.022), greater extent of enhancement (mean: 2.9 vs 2.2 quadrants, p = 0.063), and wall thinning (9.2% vs 0%, p = 0.044). Inter-reader agreement was moderate-to-good for the presence (κ = 0.64), extent (κ = 0.64), and intensity of enhancement (κ = 0.60) but relatively low for wall thinning (κ = 0.25). CONCLUSION: Aneurysms at higher risk of rupture by PHASES score are more likely to demonstrate wall enhancement, more diffuse enhancement, and wall thinning on IVW. ADVANCES IN KNOWLEDGE: This study prospectively compares IVW-detected wall enhancement and thinning between unruptured aneurysms stratified into high and low risk groups by clinical scores (PHASES) of vulnerability.

Few pathologic entities have as much of an impact both clinically and socioeconomically as traumatic brain injury (TBI). From mild concussions to severe brain injury, the spectrum of TBI encompasses a complex interplay of systemic and central nervous system pathology. TBI can be thought of as the most complex injury to the most complex system and represents a challenge for practitioners of all levels. Current and past research in TBI has been aimed at understanding the pathophysiology of injury and providing meaningful clinical tools to combating injury. The goal of this chapter is to provide a basic framework and understanding of the complexities facing practitioners treating TBI.

Background Within the current Barrow classification system, there are no categorical descriptions or reports in the literature of cavernous carotid fistulas (CCFs) with both a direct component (type A) and separate indirect contribution (type B, C, or D). We report the first definitive case of a combined simultaneous traumatic direct and indirect CCF, and review the literature on the similar existing entity of traumatic indirect CCFs presenting delayed and subsequent to the treatment of traumatic, direct CCFs. Methods We report a case of simultaneous direct type A CCF with a traumatic indirect CCF component and a review of the relevant literature. Results An 18 year-old female presented after a motor vehicle collision. A diagnostic cerebral angiogram confirmed the diagnosis of CCF, with contribution both directly from the ICA and indirectly via branches of the ECA. The direct component of the CCF was first treated in 3 stages via both transarterial and transvenous coil embolization, followed by a final 4th stage of parent vessel sacrifice in order to treat the residual direct component, with transarterial embolization to treat residual indirect CCF activity. Conclusions To our knowledge, this is the first report of a traumatic CCF with simultaneous direct (type A) and indirect via the ECA (type C) contributions.

BackgroundCavernous carotid artery aneurysms (CCAs) represent a unique subset of intracranial aneurysms due to their distinct natural history and the anatomy of the cavernous sinus. Enlarging CCAs can cause elastic compression of the parent internal carotid artery (ICA). We suggest defining aneurysms that cause luminal stenosis of their parent vessels as ‘matricidal aneurysms.’Though many patients are asymptomatic, presenting symptoms of CCAs include ophthalmoplegia with resulting diplopia, vision changes, pain, ptosis, facial numbness, and cavernous-carotid fistula. Less commonly, patients with CCAs can present with epistaxis, subarachnoid hemorrhage, and—in cases of matricidal aneurysms—ischemia due to stenosis. The proper management of stenosis caused by a matricidal CCA is not well established and may not be intuitive.MethodsWe present a multicenter retrospective case series of patients with matricidal CCAs.ResultsForty patients with matricidal aneurysms presented with both asymptomatic and symptomatic stenosis. These patients were either treated with conservative medical management, coiling, flow diversion, or endovascular sacrifice of the parent artery. Planned treatment modalities were not executed in 11 cases (28% treatment failure rate). Presenting symptoms, patient outcomes, and follow-up data are presented for all cases.ConclusionMatricidal aneurysms require careful consideration and planning. The restricted anatomy of the cavernous sinus can make successful execution of endovascular interventions more difficult. Direct elastic compression of the parent artery does not respond to angioplasty and stenting in the same way atherosclerotic stenosis does. Because of this, planning for the possibility of parent vessel sacrifice is important.

Vascular access for cerebral angiography has traditionally been performed via the common femoral artery. It is crucial to obtain safe access to prevent complications that could lead to limb ischemia, groin hematoma, or retroperitoneal hematoma. This is especially true in neurointervention as many patients are anticoagulated or have received intravenous thrombolytics prior to their intervention. Special attention to anatomic landmarks, both grossly and radiographically, can help to assure safe access. The patient consented for this procedure. This video details rapid but safe femoral artery access in a patient undergoing emergent thrombectomy.

BACKGROUND Brain arteriovenous malformations (BAVMs) are a frequent cause of pediatric hemorrhagic stroke, which frequently results in significant morbidity and mortality. OBJECTIVE To analyze the results of multimodality treatment for a consecutive series of pediatric patients with ruptured and unruptured BAVMs at a single institution. METHODS Forty patients

Transorbital neuroendoscopic surgery (TONES) is a relatively new technique that not only allows access to the contents of the orbit but also the intracranial compartment, including the anterior cranial fossa, middle fossa and lateral cavernous sinus. In this study, we aimed to retrospectively review the largest experience to our knowledge with regards to surgical outcomes of skull base pathologies treated with a TONES procedure. Forty patients (aged 3–89 years) underwent 45 TONES procedures between the years of 2006–2013. Pathologies were cerebrospinal fluid leak repair (n = 16), traumatic fracture (n = 8), tumor (n = 11), meningoencephalocele (n = 5), hematoma (n = 1), and infection (n = 4). Three patients had a persistent complication at 3 months, including a case each of enophthalmos (unnoticed by patient), epiphora (delayed presentation at 2 months requiring dacryocystorhinostomy), and ptosis (improved at 1 year). Surgical success was achieved in all patients. Of special import, there were no cases of visual decline, diplopia, or stroke. There was no mortality. To our knowledge this is the first study and largest experience of TONES (level 4 evidence) to detail outcomes with respect to skull base pathologies. Our results indicate that TONES procedures can be performed with minimal morbidity. Further studies are needed to assess equivalency with craniotomy based approaches though this initial report is encouraging.