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Background: Dural arteriovenous fistulas (dAVFs) located at craniocervical junction are extremely rare (1%-2% of intracranial/spinal dAVFs). Their angio-architectural complexity renders endovascular embolization to be challenging given multiple small feeders with risk of embolysate reflux into vertebral artery and limited transvenous access. The available literature discussing microsurgery for these lesions is limited to few case reports., Objective: To report a multicenter experience assessing microsurgery safety/efficacy., Methods: Prospectively maintained registries at 13 North American centers were queried to identify craniocervical junction dAVFs treated with microsurgery (2006-2021)., Results: Thirty-eight patients (median age 59.5 years, 44.7% female patients) were included. The most common presentation was subarachnoid/intracranial hemorrhage (47.4%) and myelopathy (36.8%) (92.1% of lesions Cognard type III-V). Direct meningeal branches from V3/4 vertebral artery segments supplied 84.2% of lesions. All lesions failed (n = 5, 13.2%) or were deemed inaccessible/unsafe to endovascular treatment. Far lateral craniotomy was the most used approach (94.7%). Intraoperative angiogram was performed in 39.5% of the cases, with angiographic cure in 94.7% of cases (median imaging follow-up of 9.2 months) and retreatment rate of 5.3%. Favorable last follow-up modified Rankin Scale of 0 to 2 was recorded in 81.6% of the patients with procedural complications of 2.6%., Conclusion: Craniocervical dAVFs represent rare entity of lesions presenting most commonly with hemorrhage or myelopathy because of venous congestion. Microsurgery using a far lateral approach provides robust exposure and visualization for these lesions and allows obliteration of the arterialized draining vein intradurally as close as possible to the fistula point. This approach was associated with a high rate of angiographic cure and favorable clinical outcomes., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

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

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.

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.

Background: 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., Methods: A retrospective review of patients treated for posterior fossa dAVFs was conducted., Results: 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., Conclusion: 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., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Introduction: Accurate sizing of the Woven EndoBridge (WEB) device is of critical importance as it determines procedural safety and successful occlusion of wide neck bifurcation aneurysms. The aim of this study was to assess the ability of aneurysm volume to assist in accurate WEB size selection., Methods: All patients with an intracranial aneurysm treated with the WEB SL or WEB SLS device between March 2019 and October 2019 were identified for this retrospective study. Aneurysm volumes were calculated with auto-segmentation using a three-dimensional volume rendering program 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. Follow-up angiographic outcomes were collected at 6-9 months post-procedure., Results: Twenty-nine aneurysms were evaluated by 3D rotational angiography. The correlation coefficient with WEB size was larger for auto-segmented aneurysm volumes (r = 0.979) compared to height × width measurements (r = 0.867). Using Fisher r-to-z transformations, we found the difference between the two correlations to be statistically significant (p = 0.0007). Follow-up angiography available in 13 subjects demonstrated an 85% complete aneurysm occlusion rate., 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 volumetric measurements of aneurysm size provide a useful adjuvant measure to assist in appropriate size selection of the WEB device.

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.

Dural arteriovenous fistulas (dAVFs) are rare vascular malformations of uncertain pathophysiology. If associated with cortical venous reflux, they present a significant risk of hemorrhage. We present a 69-year-old patient who presented with spontaneous right-sided symptomatic chronic subdural hematoma, which was evacuated via burr hole. Due to lack of history of prior trauma, computer tomography angiography was performed, which showed dilated convoluted vessels in the right occipital region and an enlarged right posterior cerebral artery, suspected to be an arteriovenous malformation or dAVF. Subsequent angiography demonstrated occipital tentorial dAVF with primary cortical venous reflux (Cognard III) and reflux into the transverse sinus, fed primarily from the petrosquamous branch of the middle meningeal artery and neuromeningeal trunk. The fistula was initially treated by transarterial endovascular embolization of the occipital artery and neuromeningeal trunk with Onyx, achieving complete obliteration. However, follow-up angiography demonstrated recurrence of the lesion fed from the contralateral middle meningeal artery and pial branches of the enlarged right posterior cerebral artery. Given the recruitment of the contralateral supply from the left middle meningeal artery and ipsilateral posterior cerebral artery, we felt that surgical disconnection of the fistula was the best option for the patient. An occipital craniotomy with disconnection of the fistula without isolation of the transverse sinus was performed (Video 1), as published literature demonstrated lower intraoperative risk with disconnection only. The perioperative course was uneventful. Immediate postoperative and follow-up angiography demonstrated complete occlusion of the fistula., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Posterior fossa dural arteriovenous fistulas (dAVFs) are rare vascular malformations. They carry a significant risk of hemorrhage if associated with cortical venous reflux. A 70-year-old man presented with right-sided medullary hemorrhage with pronounced Wallenberg syndrome. Angiography demonstrated right jugular foramen dAVF with direct brainstem venous reflux (Cognard IV). It was fed from multiple branches of the external carotid artery and the vertebral artery, and draining into the ascending pontomesencephalic vein. Primary two-stage transarterial embolization was performed with near-total occlusion of the fistula to prevent it from rebleeding in the acute phase. Because of the patient's significant neurological deficit, the surgery was deferred to later and if the DAVF showed further progression. Follow-up angiography 8 months later demonstrated obvious recurrence and progression of the fistula from adjacent feeders. In the meantime, the patient had a remarkable recovery from the Wallenberg symptoms. To achieve complete occlusion of the fistula, a right far lateral approach was chosen with complete disconnection of the fistula. Postoperative angiography confirmed complete occlusion of the fistula, and the patient remained intact from the procedure.The video can be found here: https://youtu.be/DJvpa8G4olc.

Grade III Spetzler-Martin arteriovenous malformations (AVMs) are a distinct subgroup of brain AVMs. Their variety in terms of location, type of venous drainage, and size makes them the most heterogenous group in the AVM classification. The surgical risk of treatment is also variable depending on the specifics of a given Grade III AVM. In this video illustration, the authors describe the technical nuances of surgical resection of a very complex Grade III left posterior temporal AVM. According to supplementary grading, the unruptured aspect and patient age give this lesion a Grade III; therefore, the combined grading gives the patient a score of 6, which puts him at moderate risk of morbidity for surgery. The indication for surgery was based on the patient's young age, lifetime risk of hemorrhage, and the location of the AVM in the left inferior/posterior temporal gyrus. The patient underwent 2 sessions of preoperative embolization of the posterior cerebral artery and the external carotid artery feeders prior to craniotomy. The day after the second embolization, the patient was operated on via a posterior temporobasal craniotomy. The dural supply attached to the draining vein was left intact during the dural exposure. The detail of the AVM resection is described in the video clip. A total resection was achieved, and the patient's neurological examination was intact after the procedure. The video can be found here: https://youtu.be/fj5Cxw3kpXQ .

Background: Brainstem arteriovenous malformations are challenging lesions, and benefits of treatment are uncertain., Objective: To study the clinical course of Brainstem arteriovenous malformations and the influence of treatments on outcome., Methods: We reviewed a prospective series of 31 brainstem arteriovenous malformations. Demographic, morphological, and clinical characteristics were recorded. Factors determining initial and final outcomes (modified Rankin Scale), results of treatments (cure rates, complications), and disease course were analyzed., Results: Brainstem arteriovenous malformations were symptomatic and bled in 93% and 61% of cases, respectively. Examination was abnormal and initial modified Rankin Scale score was < 3 in 71% and 86% of patients, respectively. The average follow-up time was 6.2 years, and 26% of patients rebled (5.9 %/y). Treatment modalities included conservative, radiosurgical, endovascular, surgical, and multimodality treatment in 13%, 58%, 35%, 16%, and 26% of cases, respectively. The obliteration rate was 60% overall and 39% after radiosurgery, 40% after embolization, and 75% after microsurgery, with respective complication-free cure rates of 71%, 50%, and 0%. Overall procedural mortality and morbidity were 2.3% and 18.6%, respectively. Final modified Rankin Scale score was < 3 in 77% of cases. Neurological deterioration (35%) was related to treatment complications in 74% of cases with a negative impact of surgery (P = .04), palliative embolization (odds ratio = 16), and multimodality treatments (odds ratio = 24). Radiosurgery was inversely associated with worsening (odds ratio = 0.06)., Conclusion: Brainstem arteriovenous malformations require individualized treatment decisions. Single-modality treatments with a reasonable chance of complete cure and low complication rate (such as radiosurgery) should be favored.

We describe a patient with a symptomatic left giant carotido-ophthalmic aneurysm who initially underwent coil embolization with subtotal obliteration. The patient's symptoms were initially stable, but 1 year later, she presented with a rapidly progressive contralateral visual deficit. Although angiogram showed a stable neck remnant, MR confirmed aneurysm growth and showed a new peripheral hematoma in the wall of the thrombosed aneurysm. Surgical exploration was undertaken, and even after trapping and intra-aneurysmal thrombectomy, constant bleeding was observed from the wall of the thrombosed aneurysm consistent with the vasa vasorum. Bleeding stopped after cauterization and partial resection of the aneurysm dome, and the aneurysm was clipped. The patient's recent visual deficit markedly improved, and the angiogram did not reveal any residue. Giant aneurysms may continue to grow due to a hypertrophic vasa vasorum and subadventitial hemorrhages. Surgery should be considered if complete thrombosis of the aneurysm does not alleviate patient's symptoms.

Dural arteriovenous fistulas are the most common vascular malformations of the spinal cord. These benign vascular lesions are considered straightforward targets of surgical treatment and possibly endovascular embolization, but the outcome in these cases depends mainly on the extent of clinical dysfunction at the time of the diagnosis. A timely diagnosis is an equally important factor, with early treatment regardless of the type more likely to yield significant improvements in neurological functioning. The outcomes after surgical and endovascular treatment are similar if complete obliteration of the fistulous site is obtained. In the present study, the authors evaluated the current role of each modality in the management of these interesting lesions.

Object: Spinal cord vascular malformations are rare, fascinating lesions. In this paper, the authors' goal was to demonstrate how these lesions, more specifically spinal cord arteriovenous malformations and dural arteriovenous fistulas, are assessed, classified, and managed at their institution. They also highlight some aspects of classification and management that may be different from the views of others., Methods: The authors reviewed the 20-year experience at the senior author's institution regarding the management of spinal cord vascular malformations. They discuss the management, surgical and endovascular treatment results, and the classification that resulted from the combined experience of 3 major reference centers., Results: The accumulated knowledge on embryological and pathophysiological aspects in such a rare disease resulted in a more global, patient-oriented (and not radiologically oriented) approach to spinal cord shunts., Conclusions: The multiple classifications proposed for spinal cord vascular malformations reflect the continuous advancement of the authors' understanding. They adopt a classification based on new physiological and genetic data that treats these lesions as expressions of more complex disease processes and not simply a morphological target, with direct impact on therapeutic options.

Object: This study was designed to determine whether the frequency of shunt-dependent hydrocephalus in patients suffering from aneurysmal subarachnoid hemorrhage (SAH) differs when comparing surgical clip application with endovascular obliteration of ruptured aneurysms., Methods: In this prospective nonrandomized study, 245 patients with aneurysmal SAH treated using either surgical clip application or endovascular coil embolization were studied at our institution between September 1997 and March 2003. One hundred eighty patients underwent clip application and 65 had coil embolization. In those patients who underwent clip application of anterior circulation aneurysms, the lamina terminalis was systematically fenestrated. The occurrence of acute, asymptomatic, and shunt-dependent hydrocephalus was analyzed in both treatment groups. A subgroup analysis of patients with good clinical grade (World Federation of Neurosurgical Societies [WFNS] Grades I-III) and better Fisher Grade (1-3) and of patients with Fisher Grade 4 hemorrhage was performed. Acute hydrocephalus was observed in 19% of surgical cases and 46% of endovascular ones. The occurrence of asymptomatic hydrocephalus was similar in both treatment groups (p = 0.4). Shunt-dependent hydrocephalus occurred in 14% of surgical cases and 19% of endovascular cases. This difference did not reach statistical significance (p = 0.53). Logistic regression models controlling for patient age, WFNS grade, Fisher grade, and acute hydrocephalus in patients with good clinical grade and better Fisher grade revealed no significant difference in the rate of shunt-dependent hydrocephalus in both therapy groups (odds ratio [OR] 0.8, 95% confidence interval [CI] 0.2-2.65). Results of similar models indicated that among patients with intraventricular hemorrhage (IVH), surgical clip application carried a lower risk of shunt-dependent hydrocephalus (OR 0.32, 95% CI 0.14-0.75) compared with that for endovascular embolization., Conclusions: Shunt-dependent hydrocephalus was comparable in the two treatment groups, even in patients with better clinical and radiological grades on admission. Only patients in the endovascular therapy group who had experienced IVH showed a higher likelihood of shunt-dependent hydrocephalus.

Background: Cerebral vasospasm is the most common cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (SAH). This study is designed to determine whether the incidence of symptomatic vasospasm and the overall clinical outcome differ between patients treated with surgical clipping compared with endovascular obliteration of aneurysms., Methods: In this prospective study, 98 patients with aneurysmal SAH were treated. Seventy-two patients underwent surgery and clipping and 26 had coil embolization. The incidence of symptomatic vasospasm, permanent neurologic deficit due to vasospasm and clinical outcome were analyzed. Patients with better clinical and radiological grades (World Federation of Neurological Surgeons grades I-III and Fisher grades I-III) were analyzed separately., Results: Symptomatic vasospasm occurred in 22% of the patients; 25% in the surgical group and 15% in the endovascular group. Nine percent of the patients in the surgical group and 7% in the endovascular group suffered ischemic infarction with permanent neurological deficit. These differences did not reach statistical significance (p = 0.42). For patients with better clinical and radiological grades, no significant difference was found for the rate of symptomatic vasospasm; 23% in the surgical and 12% in the endovascular group (p = 0.49). The overall clinical outcome was comparable in both groups, with no difference in the likelihood of a Glasgow Outcome Scale score of 3 or less (15% in the surgical and 16% in the endovascular group; p = 0.87). The same results for outcome were obtained for the subgroup of patients with better clinical grades on admission., Conclusion: Symptomatic vasospasm and ischemic infarction rate seem comparable in both groups, even for patients with better clinical and radiological admission grades. There is no significant difference in the overall clinical outcome at the long-term follow-up between both groups., (Copyright 2004 S. Karger AG, Basel)