The use of Onyx in different types of intracranial dural arteriovenous fistula

Feasibility, safety, and efficacy of endovascular treatment of anterior cranial fossa dural arteriovenous fistulas: a systematic review and meta-analysis with a subanalysis for Onyx

Dural Arteriovenous Fistulas (dAVFs) of the anterior cranial fossa (ACF) are uncommon but carry a high risk of hemorrhage and pose substantial treatment challenges. Recent advancements in endovascular treatment (EVT), including the introduction of novel liquid embolic agents, have markedly bolstered EVT's role in managing ACF-dAVFs, with notable series published in the last five years. We aimed to assess the feasibility, safety, and efficacy of EVT for ACF-dAVFs. We searched Medline, Scopus, Web of Science, and Cochrane Library databases following PRISMA guidelines. Eligible studies included those with ≥ 5 patients undergoing embolization of ACF-dAVFs, detailing both angiographic and clinical outcomes. We used single proportion analysis with 95% confidence intervals under a random-effects model, I2 to assess heterogeneity, and Baujat and sensitivity analysis to address high heterogeneity. Publication bias was assessed by funnel-plot analysis and Egger's test. Outcomes included complete occlusion following embolization, unsuccessful endovascular embolization attempts, incomplete occlusion following embolization, symptom resolution or clinical improvement following embolization, recurrence; procedure-related complications, morbidity, and mortality. Additionally, a subanalysis for studies exclusively utilizing Onyx™ embolic system was done. Eighteen studies comprising 231 ACF-dAVF were included. Unsuccessful endovascular embolization attempts rate was 2%. Complete occlusion rate was 85%, with 4% of complications. Incomplete occlusion rate was 10%. Successfully embolized patients experienced either symptom resolution or clinical improvement in 94% of cases. Morbidity and mortality rates were 1% and 0%, respectively. Onyx subanalyses showed an overall rate of 0% for unsuccessful attempts, 95% for complete occlusion, and 5% for incomplete occlusion. Symptom resolution or clinical improvement was 98% and recurrence rate was 0%. EVT for ACF-dAVF is highly feasible, effective, and safe, with a low rate of complications, morbidity, and mortality. The subanalyses focusing on Onyx embolizations revealed superior efficacy and safety outcomes compared to the findings of the primary analyses involving all included studies.

Transvenous embolization of noncavernous dural arteriovenous fistulas (dAVFs): A systematic review and meta-analysis

BACKGROUND

Intracranial dural arteriovenous fistulas (dAVFs) are abnormal connections between arteries and veins within the dura mater. Various treatment modalities, such as surgical ligation, endovascular intervention, and radiosurgery, aim to close the fistulous connection. Although transvenous embolization (TVE) is the preferred method for carotid-cavernous fistulas, its description and outcomes for noncavernous dAVFs vary. This has prompted a systematic review and meta-analysis to comprehensively assess the effectiveness of TVE in treating noncavernous dAVFs, addressing variations in outcomes and techniques.

METHODS

We searched PubMed and Embase, spanning from the earliest records to December 2022, to identify pertinent English-language articles detailing the utilization of TVE. We focused on specific procedural details, outcomes, and complications in patients older than 18 years. The data collected and analyzed comprised the sample size, number of fistulas, publication specifics, presenting symptoms, fistula grades, and pooled rates of embolizations, outcomes, follow-up information, and complications.

RESULTS

From a total of 565 screened articles, 15 retrospective articles encompassing 166 patients spanning across seven countries met the inclusion criteria. Their Newcastle-Ottawa scores ranged from 6 to 8. Intraprocedural complication rate was 10% (95% confidence interval [CI] = 5.9-17.1) and in-hospital postprocedural complication rate was 5.4% (95% CI = 2.8-10.6). Prevalence of in-hospital mortality was 5.5% (95% CI = 2.9-10.6). Complication rate during follow-up was 8.6% (95% CI = 4.7-15.7) with fistula rupture occurring in 5.5% (95% CI = 2.6-11.6) of patients. Complete obliteration rate at final angiographic follow-up was 94.9% (95% CI = 90.3-99.9). Symptoms improved in 95% (95% CI = 89.8-100) of patients at final follow-up.

CONCLUSION

To our knowledge, we present the first meta-analysis assessing obliteration rates, outcomes, and complications of TVE for dAVFs. Our analysis highlights the higher (>90%) complete obliteration rates. Large prospective multicenter studies are needed to better define the utility of TVE for noncavernous dAVFs.

Watch brain circulation in unexplained progressive myelopathy: a review of Cognard type V arterio-venous fistulas

BACKGROUND

Intracranial dural arterio-venous fistulas are pathological anastomoses between arteries and veins located within dural sheets and whose clinical manifestations depend on location and hemodynamic features. They can sometimes display perimedullary venous drainage (Cognard type V fistulas-CVFs) and present as a progressive myelopathy. Our review aims at describing CVFs' variety of clinical presentation, investigating a possible association between diagnostic delay and outcome and assessing whether there is a correlation between clinical and/or radiological signs and clinical outcomes.

METHODS

We conducted a systematic search on Pubmed, looking for articles describing patients with CVFs complicated with myelopathy.

RESULTS

A total of 72 articles for an overall of 100 patients were selected. The mean age was 56.20 ± 14.07, 72% of patients were man, and 58% received an initial misdiagnosis. CVFs showed a progressive onset in 65% of cases, beginning with motor symptoms in 79% of cases. As for the MRI, 81% presented spinal flow voids. The median time from symptoms' onset to diagnosis was 5 months with longer delays for patients experiencing worse outcomes. Finally, 67.1% of patients showed poor outcomes while the remaining 32.9% obtained a partial-to-full recovery.

CONCLUSIONS

We confirmed CVFs' broad clinical spectrum of presentation and found that the outcome is not associated with the severity of the clinical picture at onset, but it has a negative correlation with the length of diagnostic delay. We furthermore underlined the importance of cervico-dorsal perimedullary T1/T2 flow voids as a reliable MRI parameter to orient the diagnosis and distinguish CVFs from most of their mimics.

Intracranial Non-Sinus-Type Dural Arteriovenous Fistulas Could Be Curable by Transarterial Embolization or Transvenous Embolization with Liquid Embolic Material

Objective

Recently, the occlusion rate of transarterial embolization (TAE) for intracranial non-sinus-type dural arteriovenous fistulas (NSDAVFs) has improved after ONYX was introduced. Additionally, when TAE for NSDAVF is unsuccessful, transvenous embolization (TVE) has become available as an alternative treatment. We investigated the factor for the favorable occlusion rate of endovascular treatment for NSDAVF at our institutions.

Methods

Two hundred and twenty-seven patients with intracranial dural arteriovenous fistulas (DAVFs) were treated at our institutions between September 2014 and October 2022. The patients diagnosed with NSDAVF in all DAVFs who underwent endovascular treatment were included. The clinical characteristics, angiographical outcomes, and clinical outcomes of patients who underwent endovascular treatment were evaluated.

Results

Thirty-eight patients had intracranial NSDAVF (tentorial: 23 cases, parasagittal-convexity: 7, anterior cranial fossa: 6, middle cranial fossa: 2). Our participants' mean age was 64.8 ± 11.3 years, and 31 (81.6%) of them were males. Patients' symptoms were as follows: asymptomatic (24), hemorrhage (10), tinnitus (3), and trigeminal neuralgia (1). TAE and TVE were performed on 35 and 3 patients, respectively. The rate of immediate angiographical occlusion was 84.2% (32/38). The follow-up angiographical occlusion rate in 6 months was 88.5% (31/35). Complications occurred in three cases. There was no morbidity or mortality after 30 days.

Conclusion

TAE using the combination of the new microcatheter and microguidewire and TVE in the case of difficult or failed TAE for NSDAVF could achieve high success rates and safety.

Our Experience of Eight Patients with Dural Arteriovenous Fistula's at Foramen Magnum with Respect to Presentation, Angioarchitecture, and Endovascular Treatment Outcomes

Background Dural arteriovenous fistulas (DAVFs) around foramen magnum (FM) with peri medullary venous drainage, are uncommon and have wide spectrum of presentation. Literature about this lesion is sparse. We intent to analyze and report our experience with these cases with respect to presentation, evaluation, and endovascular treatment outcomes.

Materials and Methods All the eight patients who were diagnosed with DAVFs at FM and treated with transarterial embolization using ethylene viny alcohol were included in this study. Clinical record sheets, radiological, and angiographic data of these patients were retrieved from our departmental database.

Results Duration of symptoms ranged from 1 day to 3 years. Presentation with progressive ascending sensory symptoms and weakness (N = 4), acute headache (N = 2) acute quadriplegia (N = 1), and right ear bruit (N = 1) was seen. Exclusive feeders from occipital artery (OA) and vertebral artery (VA) were seen in two and four patients, respectively. Dual feeders from a combination of ascending pharyngeal artery and VA; from a combination of OA and VA were seen in one patient each. The exclusive venous drainage to spinal peri medullary veins (N = 3), brain stem peri medullary veins (N = 1), and both combined (N = 4). Two patients had a draining vein aneurysm. Complete obliteration of fistula was achieved in all patients. Complete resolution of symptoms was seen in six patients; two patients had significant improvement.

Conclusion The clinical presentation of dural AVF at foramen magnum is wide ranging and these lesions can be treated effectively and safely by transarterial embolization. Duration of symptoms strongly influences the final patient outcome.

Microcatheters with extra-long detachable tip: A promising treatment option in dural arteriovenous fistulas

PURPOSE

Treating cerebral dural arteriovenous fistulas (dAVFs) by transarterial embolization is an established endovascular approach but no data exist regarding the utility of using the newly introduced microcatheters with extra-long detachable tip. Aim of our study was to evaluate the value of these microcatheters and, additionally, of combining them with the simplified pressure cooker technique.

METHODS

Twenty-nine patients treated for dAVF with transarterial embolization were enrolled. In a subgroup of fifteen patients the simplified pressure cooker technique was additionally applied. Demographics and characteristics were collected for patients and dAVFs and procedural details reviewed. The association between covariates and binary-coded occlusion status was evaluated.

RESULTS

Microcatheter navigation into the target pedicle as well as application of the simplified pressure cooker technique were successful in all cases. Complete dAVF occlusion was reached in 69.0% at a single stage. In case of complete dAVF occlusion, embolization via only one pedicle was enough. Subgroup analysis revealed a higher occlusion status (80%) if using the simplified pressure cooker technique than if not (57%) but reached not significance level.

CONCLUSION

Using microcatheters with extra-long detachable tip for dAVF embolization seems to offer a safe and effective treatment option with exceptional high occlusion rate at a single stage. The high navigability facilitates catheterization of a single selected target pedicle that is often enough to reach complete dAVF occlusion. Combining these microcatheters with the simplified pressure cooker technique turned out to be safe and easy to handle and might allow an increasing dAVF occlusion rate.

The Middle Meningeal Artery: Branches, Dangerous Anastomoses, and Implications in Neurosurgery and Neuroendovascular Surgery

The middle meningeal artery (MMA) has always been the workhorse corridor for devascularization of dural-based intracranial lesions and, more recently, has been established as a target for the endovascular management of chronic subdural hematomas. The MMA anatomy is complex and deceitful, and its territory of irrigation (including cranial nerves) is poorly understood. Furthermore, MMA variations and anastomoses are more frequent than expected, which may predispose to procedure-related morbidity. A literature search was conducted in electronic databases per PRISMA guidelines for studies describing normal and abnormal MMA anatomy including variations in MMA origin and dangerous anastomoses. Our institutional case series of greater than 100 MMA embolizations for management of chronic subdural hematomas were reviewed for abnormal MMA anatomy, and clinically relevant case examples are presented. In this article, we provide a comprehensive review of the MMA to provide a better understanding and appreciation of this artery, including pearls and pitfalls, that we hope will aid the neurosurgeon and neurointerventionalist in safely tackling these lesions.

A Case of Pterygopalatine Fossa Arteriovenous Malformation Treated by Transarterial Embolization Using a Dual-Lumen Balloon Catheter

Objective

We report a rare case of pterygopalatine fossa arterial venous shunt disease with venous congestion of the superior ophthalmic vein (SOV) that was treated by transarterial balloon-assisted embolization.

Case Presentation

A 57-year-old man presented with congestion of the right bulbar conjunctiva, protrusion, and swelling of the right eyelid was admitted to our hospital. Angiography demonstrated an arteriovenous fistula (AVF) forming small congregated vessels in the pterygopalatine fossa fed by the branch of the ophthalmic artery (OA) and artery of the superior orbital fissure, draining into the SOV via the inferior ophthalmic vein (IOV). From the artery of the superior orbital fissure, transarterial embolization (TAE) with ONYX using a dual-lumen balloon catheter was performed. The patient was treated without complications.

Conclusion

TAE using transarterial balloon-assisted embolization with ONYX is effective for periorbital arteriovenous shunts, although special care is necessary to prevent the migration of ONYX into the OA.

The "Shiny and Thick High Heel Sign" : A novel radiologic sign for detecting intracranial dural arteriovenous fistulas with time-of-flight magnetic resonance angiography

PURPOSE

Together with the foramen ovale, the middle meningeal artery (MMA) looks like a high heel shoe print on axial time-of-flight magnetic resonance angiography (TOF-MRA) images, with the MMA resembling the heel. Cranial dural arteriovenous fistulas (DAVF) are often fed by the MMA, which can lead to an increase of signal intensity and diameter of this vessel, resulting in a more "shiny" and "thick" high heel print appearance than on the contralateral side. We describe this finding as a novel radiologic sign and provide cut-off values for the ratios of MMA signal intensities and diameters for predicting the presence of a DAVF.

METHODS

A total of 84 TOF-MRA examinations of 44 patients with DAVFs (40 with unilateral MMA feeders, 4 with bilateral feeders) and of 40 patients without DAVFs were included. Diameters and signal intensities of both MMAs were measured by two raters and evaluated using receiver operating characteristic analysis.

RESULTS

The diameters of feeding and non-feeding MMAs differed significantly, as did the ratios of signal intensities and of diameters of DAVF and control patients (P < 0.0001). Cut-off values were 1.25 for average signal intensity ratio (shiny high heel sign) and 1.21 for diameter ratio (thick high heel sign). The combination of the "shiny" and the "thick" high heel sign resulted in the highest sensitivity (92.5%) and positive predictive value (95%).

CONCLUSION

The described sign seems promising for the detection of DAVFs with noncontrast-enhanced MRI. The TOF-MRA source images should be reviewed with special attention to the MMA.

Scepter dual-lumen balloon catheter for Onyx embolization for dural arteriovenous fistula

Background

This study aimed to evaluate the efficacy and safety of Scepter dual-lumen balloon catheter for transarterial Onyx embolization of dural arteriovenous fistula (DAVF).

Methods

Transarterial Onyx embolization using a Scepter dual-lumen balloon catheter (Scepter-assisted Onyx embolization) for DAVF was attempted in a total of 35 patients (mean age, 52.5 years; M:F = 24:11) between October 2012 and December 2018. The results of Scepter-assisted Onyx embolization were evaluated with respect to total procedural and Onyx injection times, the types and number of feeders requiring embolization, angiographic and clinical outcomes, and treatment-related complications.

Results

Initial presentations were non-hemorrhagic neurological deficits in 10, intracranial hemorrhage in 8, seizure in 7, headache in 7, and intractable tinnitus in 3. All DAVF were aggressive type (Borden type 2, 14.3 %; type 3, 85.7 %). Scepter-assisted Onyx embolization resulted in immediately complete occlusion in 33 patients (94.3 %) and near complete occlusion in 2 patients. Middle meningeal artery (51.4 %) was the most commonly used for Scepter-assisted technique, followed by occipital artery (42.9 %), ascending pharyngeal artery (2.9 %) and superficial temporal artery (2.9 %). There was no difference in complete occlusion rate between middle meningeal artery and the other arteries (94.4 % versus 94.1 %). The median number of total feeders embolized was 1 (range, 1–3). The median total procedural time was 45 minutes (range, 21 minutes – 127 minutes) and the median Onyx injection time was 11 minutes (range, 3 minutes – 25 minutes). All patients recovered completely (n = 31) or partially (n = 4) from presenting symptoms. Treatment-related complications occurred in 2 patients, of whom one had a permanent morbidity (2.8 %, ipsilateral facial nerve palsy). No patient showed a recurrence on follow-up imaging (median, 15 months; range, 3–56 months).

Conclusions

Scepter-assisted transarterial Onyx embolization showed a very high complete occlusion rate with a low morbidity and no recurrence in aggressive type DAVF. Scepter dual-lumen balloon catheter seems to be a useful tool for transarterial Onyx embolization of DAVF.

Stereotactic Radiosurgery for Cavernous Sinus Versus Noncavernous Sinus Dural Arteriovenous Fistulas: Outcomes and Outcome Predictors

BACKGROUND

Dural arteriovenous fistulas (DAVFs) can be categorized based on location.

OBJECTIVE

To compare stereotactic radiosurgery (SRS) outcomes between cavernous sinus (CS) and non-CS DAVFs and to identify respective outcome predictors.

METHODS

This is a retrospective study of DAVFs treated with SRS between 1988 and 2016 at 10 institutions. Patients' variables, DAVF characters, and SRS parameters were included for analyses. Favorable clinical outcome was defined as angiography-confirmed obliteration without radiological radiation-induced changes (RIC) or post-SRS hemorrhage. Other outcomes were DAVFs obliteration and adverse events (including RIC, symptomatic RIC, and post-SRS hemorrhage).

RESULTS

The overall study cohort comprised 131 patients, including 20 patients with CS DAVFs (15%) and 111 patients with non-CS DAVFs (85%). Rates of favorable clinical outcome were comparable between the 2 groups (45% vs 37%, P = .824). Obliteration rate after SRS was higher in the CS DAVFs group, even adjusted for baseline difference (OR = 4.189, P = .044). Predictors of favorable clinical outcome included higher maximum dose (P = .014) for CS DAVFs. Symptomatic improvement was associated with obliteration in non-CS DAVFs (P = .005), but symptoms improved regardless of whether obliteration was confirmed in CS DAVFs. Non-CS DAVFs patients with adverse events after SRS were more likely to be male (P = .020), multiple arterial feeding fistulas (P = .018), and lower maximum dose (P = .041).

CONCLUSION

After SRS, CS DAVFs are more likely to obliterate than non-CS ones. Because these 2 groups have different total predictors for clinical and radiologic outcomes after SRS, they should be considered as different entities.

Facial Nerve Paralysis Following Endovascular Embolization: A Case Report and Review of the Literature

OBJECTIVE

We report a case of facial nerve paralysis post-endovascular embolization of a sigmoid sinus dural arterio-venous fistula from initial presentation to current management and discuss the merits of observation versus decompression through a systematic review of relevant literature.

PATIENT

61 F with right facial palsy.

INTERVENTION

Following a single intravenous dexamethasone injection with oral steroids over 2 months, patient was observed with no additional treatment other than Botox chemodenervation and facial rehabilitation.

OUTCOME AND RESULTS

The patient initially presented with complete right facial palsy (HB 6/6). Post-op CT imaging indicated Onyx (ev3, Irvine, California, USA) particles present at the geniculate segment of the facial nerve. Observation was chosen over surgical intervention. At the most current follow up of 8 months, facial function has improved substantially (HB 2/6).

CONCLUSION

Facial palsy is a serious, though rare, complication of transarterial endovascular embolization. With our case report and literature review, we highlight not only how conservative observation is the recommended treatment, but also that facial nerve recovery should be expected to reach near complete recovery, but not sooner than in 3 months.

Efficacy and safety of embolization of dural arteriovenous fistulas via the ophthalmic artery

INTRODUCTION

Dural arteriovenous fistulae (DAVF) are vascular lesions with arteriovenous shunting that may be treated with surgical obliteration or endovascular embolization. Some DAVF, such as anterior cranial fossa DAVF (AC-DAVF) derive their arterial supply from ophthalmic artery branches in nearly all cases, and trans-arterial embolization carries a risk of vision loss. We determined the efficacy and safety of trans-ophthalmic artery embolization of DAVF.

MATERIALS AND METHODS

We performed a retrospective cohort study of all patients with DAVF treated by trans-ophthalmic artery embolization from 2012 to 2020. Primary outcome was angiographic cure of the DAVF. Secondary outcomes included vision loss, visual impairment, orbital cranial nerve injury, stroke, modified Rankin Scale at 90-days, and mortality.

RESULTS

12 patients met inclusion criteria (9 males; 3 females). 10 patients had AC-DAVF. Patient age was 59.7  ±  9.5 (mean ± SD) years. Patients presented with intracranial hemorrhage (4 patients), headache (4 patients), amaurosis fugax (1 patients), or were incidentally discovered (2 patients). DAVF Cognard grades were: II (1 patient), III (6 patients), and IV (5 patients). DAVF were embolized with Onyx (10 patients), nBCA glue (1 patient), and a combination of coils and Onyx (1 patient). DAVF cure was achieved in 11 patients (92%). No patients experienced vision loss, death, or permanent disability. One patient experienced a minor complication of blurry vision attributed to posterior ischemic optic neuropathy. 90-day mRS was 0 (10 patients) and 1 (2 patients).

CONCLUSIONS

Trans-ophthalmic artery embolization is an effective and safe treatment for DAVF.

Long-term follow-up of transarterial balloon-assisted Onyx embolization for endovascular treatment of dural arteriovenous fistulas: A single-institution case series and literature review

OBJECTIVE

Dural arteriovenous fistulas (DAVFs)-specifically, symptomatic DAVFs with cortical venous reflux-are aggressive lesions with a poor prognosis. Intra-arterial endovascular closure is considered the optional treatment for DAVFs and is currently performed at several international centers. However, long-term outcomes remain unknown. This study investigated the long-term efficacy and safety of transarterial balloon-assisted Onyx embolization in the treatment of DAVFs.

METHODS

A total of 14 consecutive patients who underwent endovascular treatment for DAVFs were treated by balloon-assisted Onyx embolization. Additionally, we retrospectively reviewed all cases reported in the literature and compared the outcomes of patients treated with single- vs dual-lumen microcatheters.

RESULTS

The patients at our institution were followed-up for 114.57 ± 33.52 months. Embolization was performed by balloon-assisted Onyx injection via a single feeding artery. Complete occlusion was achieved in 13 cases and partial occlusion in 1 case. At the final follow-up, all patients were functionally independent (Modified Rankin Scale score of 0-2), with no recurrence. In our review of 70 published cases of DAVFs that underwent endovascular treatment by balloon-assisted Onyx embolization, single- and dual-lumen balloon catheters were used in 33 and 37 patients, respectively. In the former group, there was complete or near-complete occlusion in 32 cases and partial occlusion in 1 case; and in the latter, there was complete or near-complete occlusion in 35 cases and partial occlusion in 2 cases. There were no deaths following endovascular treatment.

CONCLUSION

Measurable and durable outcomes can be achieved by endovascular treatment of DAVFs with the transarterial balloon-assisted Onyx embolization technique, especially in cases with small, distal, and circuitous feeding arteries.

Transarterial Treatment of Cranial Dural Arteriovenous Fistulas: The Role of Transarterial and Transvenous Balloon-Assisted Embolization

BACKGROUND AND PURPOSE

Treatment of dural arteriovenous fistulas can be performed by transarterial or transvenous accesses. For those fistulas located at a dural sinus wall, obliteration of the sinus might lead to a substantial risk of complications if the occluded sinus impairs normal venous drainage. For those fistulas with direct leptomeningeal venous drainage, navigation to reach the arteriovenous shunting point of a leptomeningeal vein is usually technically demanding. We report the outcomes of patients with dural AVFs treated by transarterial injection of liquid embolic agents assisted by transarterial double-lumen balloon catheters and/or transvenous balloon catheters.

MATERIALS AND METHODS

This was a retrospective, 3-center study including patients with dural AVFs treated with a balloon-assisted technique in at least 1 treatment session. Angiographic follow-up was performed at 6 months. Clinical assessment was performed at admission and discharge and was reassessed at 30-day and 6-month follow-ups.

RESULTS

Forty-one patients with 43 dural AVFs were treated. Thirty-four fistulas were located at a dural sinus wall. Treatment was performed using only a transarterial approach in 42 fistulas. Only 1 session was needed for complete obliteration of the fistula in 86% of the patients. Immediate complete angiographic occlusion was achieved in 39 fistulas. Of the 41 controlled fistulas, 40 (97.6%) were completely occluded at 6 months. Thirty-nine fistulas (95.1%) were cured without any report of major neurologic events or death during follow-up.

CONCLUSIONS

Transarterial balloon-assisted treatment of dural AVFs with or without transvenous balloon protection was shown to be safe and effective.

Balloon-assisted Onyx Embolization in the Management of Complicated Dural Arterioevenous Fistula

Objective

Dural arteriovenous fistula (dAVF) is an abnormal vascular communication between the meningeal artery and vein at the dura mater, with frequent recruitment of collateral arterial pedicles. In recent years, Onyx embolization has become the mainstay intervention for dAVF at various locations, although an unfavorable vascular anatomy often limits effective obliteration of the lesion. Balloon assistance may facilitate curable occlusion of the abnormal shunt with Onyx while preserving the patency of the affected sinus, even in complicated dAVFs.

Methods

We retrospectively reviewed the clinical and angiographic findings of patients with dAVF treated endovascularly in our institution between September 2018 and August 2019. Based on the detailed analysis of individual angioarchitecture, we defined complicated dAVF as lesions for which a complete cure is considered difficult to achieve with simple transarterial Onyx embolization alone, primarily due to a high flow and/or diffuse shunt with or without drainage to the functioning but compromised sinus. We evaluated the preoperative symptoms, anatomical classification, endovascular procedure, radiologic results, and clinical outcomes of these patients.

Results

Five patients met our criteria, all of whom were treated with balloon-assisted Onyx embolization (two superior sagittal sinus dAVF, two transverse-sigmoid sinus dAVF, and one torcular dAVF). In four cases, Onyx was injected from a tiny branch of the middle meningeal artery under balloon occlusion of the collateral arteries or balloon devascularization of the competitive inflow. In three cases, balloon sinus protection was performed to prevent the inadvertent occlusion of the vital venous outflow with Onyx. In one case, for the complementary occlusion of the remnant shunt through the previously coiled but recanalized occipital artery, Onyx was injected from the wire lumen of a dual-lumen balloon catheter to avoid undesirable reflux. The angiographic results were an anatomical cure in four cases and near-complete occlusion in one case. No procedural complications were observed in any cases. The clinical outcome was a complete cure in four cases and improvement in one case.

Conclusion

Our cases suggest that balloon devascularization can improve the unfavorable flow environment and simplify the vascular anatomy. Balloon sinus protection can support not only securing the patency of the normal venous outflow but also encourage aggressive intervention. Onyx injection via a dual-lumen balloon catheter can augment the controllability of embolization while preventing reflux. Each of these techniques can facilitate safe and effective Onyx embolization in the treatment of complicated dAVFs, and their combination may further expand the therapeutic horizon.

The Influence of Angioarchitectural Features on the Success of Endovascular Embolization of Cranial Dural Arteriovenous Fistulas with Onyx

BACKGROUND AND PURPOSE

Endovascular embolization can be an effective treatment for cranial dural arteriovenous fistulas. However, a considerable number of dural arteriovenous fistulas still cannot be treated sufficiently. The purpose of this study was to report our single-center experience of endovascular embolization of dural arteriovenous fistulas with Onyx, including the investigation of the influence of angioarchitectural features on the treatment success.

MATERIALS AND METHODS

Clinical data, angioarchitectural features, complications, treatment success (defined as complete symptom remission for low-grade dural arteriovenous fistulas and complete occlusion for high-grade dural arteriovenous fistulas), and occlusion rates were assessed. The influence of various angioarchitectural features (including location, pattern of venous drainage, and quantity and origin of feeding arteries) was investigated using multivariable backward logistic regression.

RESULTS

One hundred four patients with 110 dural arteriovenous fistulas were treated in 132 treatment procedures. Treatment success and complete occlusion rates were 81.8% and 90.9%, respectively. After a mean follow-up of 23.6 months, 95.5% of the patients showed complete symptom remission or symptom relief. The overall complication rate was 8.3% (4.5% asymptomatic, 2.3% transient, and 1.5% permanent complications). Logistic regression showed that ≥10 feeding arteries (P = .041) and involvement of the ascending pharyngeal artery (P = .039) significantly lowered the probability of treatment success. Treatment success tended to be lower for low-grade dural arteriovenous fistulas, Cognard type I dural arteriovenous fistulas, and dural arteriovenous fistulas with involvement of dural branches of the internal carotid artery, however without reaching statistical significance in the multivariable model.

CONCLUSIONS

The presence of multiple feeding arteries and involvement of the pharyngeal artery negatively influence the treatment success of endovascular embolization of cranial dural arteriovenous fistulas with Onyx.

Anterior cranial fossa dural arteriovenous fistula: Transarterial embolization from the ophthalmic artery as first-line treatment

OBJECTIVE

To retrospectively review the outcome of patients with dural arteriovenous fistula of the anterior cranial fossa (afDAVF) treated by transarterial embolization.

MATERIAL AND METHODS

Six consecutive patients were referred to our hospital for afDAVF treatment. After a multidisciplinary discussion, they underwent endovascular embolization with Onyx injection through the ophthalmic artery. Their clinical presentation, management and outcomes were retrospectively assessed.

RESULTS

All interventions were performed with the liquid embolic agent Onyx through the transarterial route from the ophthalmic artery to access the fistulous point. All patients showed a good outcome with complete afDAVF obliteration.

CONCLUSION

This study demonstrates that afDAVFs can be safely and completely obliterated by transarterial embolization via the ophthalmic artery.

Dural Arteriovenous Fistulas with Perimedullary Venous Drainage Successfully Managed Via Endovascular Electrocoagulation

BACKGROUND

Dural arteriovenous fistulas (DAVFs) with perimedullary venous drainage are very rare intracranial DAVFs. Treating DAVF via an endovascular electrocoagulation technique, to the best of our knowledge, has not been reported in the literature. We therefore report the first successful case.

CASE DESCRIPTION

We report a rare case of Cognard type V DAVF. The feeding arteries were the middle meningeal artery, the recurrent meningeal branch of ophthalmic artery, and the meningohypophyseal trunk. The patient presented with paresthesia and weakness in the lower limbs. T2-weighted magnetic resonance imaging revealed a high signal in the medulla oblongata and upper cervical spinal cord. Our first procedure via the middle meningeal artery with Onyx 18 (ev3 Neurovascular) as the embolization agent failed to occlude the fistula. We finally occluded the fistula with the endovascular electro-coagulation technique. Two-year follow-up revealed total disappearance of the fistula and relieve of patient's symptoms.

CONCLUSIONS

The endovascular electrocoagulation technique is very effective in the management of complex DAVFs with perimedullary venous drainage.

Treatment Outcomes According to Various Treatment Modalities for Intracranial Dural Arteriovenous Fistulas in the Onyx Era: A 10-Year Single-Center Experience

BACKGROUND

Although transarterial embolization (TAE) with Onyx has become popular for the treatment of dural arteriovenous fistulas (DAVFs), transvenous embolization (TVE), surgery, and radiosurgery have continued to have a role. The aim of the present study was to compare the treatment outcomes stratified by the different treatment modalities.

METHODS

The data from 92 patients with DAVFs treated from January 2009 to June 2018 were retrospectively reviewed. The treatment strategies were decided by a multidisciplinary team according to the patient's clinical status and angiographic findings. The clinical and radiologic data were analyzed and correlated with the treatment modality.

RESULTS

A total of 101 procedures were performed in the 92 patients. TAE, TVE, surgery, and radiosurgery were performed in 31, 49, 12, and 9 procedures, respectively. Complete and near complete occlusion was achieved in 13 cases treated with TAE (41.9%), 41 treated with TVE (83.7%), and 10 with surgery (83.3%), as shown on immediate postprocedural angiography (P < 0.001). Retreatment was needed in 9 patients in the TAE group and none in the TVE or surgery groups (P < 0.001). Surgery (n = 1), TVE (n = 3), TAE (n = 1), and radiosurgery (n = 4) were used for patients requiring retreatment. At the last follow-up examination (mean, 26.5 ± 23.9 months), 66 of 72 DAVFs (91.6%) showed angiographic complete occlusion. Clinically, the initial symptoms had disappeared or improved in 87 of 90 patients (96.7%) at the last follow-up evaluation (mean, 26.4 ± 26.8 months).

CONCLUSIONS

Even in the Onyx era, other treatment modalities still have important roles, as shown in the present study. Therefore, the selection of the appropriate treatment modality should be individualized by the angiographic findings and clinical symptoms.

Transvenous embolization of arteriovenous malformations

Embolization of arteriovenous malformations is characteristically used as part of a multimodal treatment approach, pre-operatively to facilitate microsurgical resection or as a preradiosurgical adjunct. The concept of AVM cure via embolization alone has gained popularity in recent years. Embolization of AVMs has been most commonly performed transarterially, with the transvenous route traditionally eschewed given concern over precipitating premature venous occlusion and consequent hemorrhage. However, the transvenous approach in treating AVMs offers several distinct advantages compared to the transarterial route and can be used in instances when the latter is not feasible, with several series having proven its efficacy and safety. Conceptually, AVM embolization performed via the transvenous route achieves complete obliteration by directly and facilely targeting the nidus. Nidal embolisate penetration is facilitated by control of arterial inflow via systemic or local hypotension. Innovation in endovascular strategies has led to significantly improved obliteration rates. The experience with transvenous AVM embolization is reviewed and discussed.

Outcome of transarterial treatment of dural arteriovenous fistulas with direct or indirect cortical venous drainage

BACKGROUND AND PURPOSE

Transarterial Onyx embolization is an effective treatment for patients with intracranial dural arteriovenous fistula (DAVF). A study was performed to determine whether the clinical and radiological outcomes after transarterial Onyx treatment were affected by the type of cortical venous drainage (direct vs indirect) of high-grade DAVF.

MATERIALS AND METHODS

Between May 2006 and December 2014, demographic data, clinical presentation, angiographic characteristics, and treatment-related outcomes were collected for 54 patients divided into two groups (intracranial DAVF with direct and indirect cortical venous drainage). Continuous variables were compared with the two-tailed t test and categorical variables with the χ² test. Statistical significance was set at P<0.05.

RESULTS

Fifty-two patients (71% with direct and 29% with indirect cortical venous drainage) underwent Onyx embolization. Immediate complete occlusion after treatment was observed in about 55% of patients without between-group difference. During the long-term follow-up, complete angiographic occlusion was achieved in 83% of patients. Specifically, 15 additional patients (40%) in the direct cortical venous drainage group progressed to complete occlusion, but only one (6%) in the indirect cortical venous drainage group. Overall, the rate of complete occlusion was higher in patients with DAVF with direct cortical venous drainage (92%) than in those with DAVF with indirect cortical venous drainage (62.5%) (P=0.01). The rate of permanent treatment-related complications was 4%, mostly related to ischemic events. Overall, 80.5% of patients had a good neurological outcome (modified Rankin Scale score 0-2).

CONCLUSIONS

Transarterial Onyx embolization of intracranial high-grade DAVF is safe and effective, particularly for lesions with direct cortical venous drainage.

Cranial Nerve Palsy after Onyx Embolization as a Treatment for Cerebral Vascular Malformation

The Onyx liquid embolic system is a relatively safe and commonly used treatment for vascular malformations, such as arteriovenous fistulas and arteriovenous malformations. However, studies on possible complications after Onyx embolization in patients with vascular malformations are limited, and the occurrence of cranial nerve palsy is occasionally reported. Here we report the progress of two different types of cranial nerve palsy that can occur after embolization. In both cases, Onyx embolization was performed to treat vascular malformations and ipsilateral oculomotor and facial nerve palsies were observed. Both patients were treated with steroids and exhibited symptom improvement after several months. The most common types of neuropathy that can occur after Onyx embolization are facial nerve palsy and trigeminal neuralgia. Although the mechanisms underlying these neuropathies are not clear, they may involve traction injuries sustained while extracting the microcatheter, mass effects resulting from thrombi and edema, or Onyx reflux into the vasa nervorum. In most cases, the neuropathy spontaneously resolves several months following the procedure.

A challenging entity of endovascular embolization with ONYX for brainstem arteriovenous malformation: Experience from 13 cases

Objective Brainstem arteriovenous malformations (AVMs) are rare lesions with a high risk of intracranial hemorrhage and are challenging to treat. We present our experience of endovascular embolization with Onyx in these aggressive lesions. Materials and methods Between 2007 and 2016, 13 patients with brainstem AVMs were embolized with Onyx at our center. Twelve patients presented with intracranial hemorrhage and one with headache. Retrospective examinations of patient demographics, clinical presentation, angiographic features, treatment modalities, postoperative complications and outcomes were carried out. Results The AVMs were in the midbrain in 10 patients (one anterior and nine posterior or dorsal), in the posterior pons in two and pontomedullary in one. Complete occlusion was achieved in three patients. Gamma knife radiosurgery was performed in six patients who were near-completely or partially embolized. Postoperative complications, including five cases of ischemia and one case of hemorrhage, resulted in four cases of neurological deterioration and two deaths. Clinical follow-up was obtained in 10 patients at a mean period of 45.2 months (range 3 to 93 months). During the follow-up, good clinical outcomes were observed in seven patients with posterior or dorsal midbrain AVMs, and one patient with a posterior pons AVM that was partially occluded died of intracranial hemorrhage. Conclusion Endovascular embolization for brainstem AVM with Onyx is a technical challenge and the reflux of Onyx may cause severe complications. Individualized treatment is needed based on the specific subtype of brainstem AVM.

Safety of Onyx Transarterial Embolization of Skull Base Dural Arteriovenous Fistulas from Meningeal Branches of the External Carotids also Fed by Meningeal Branches of Internal Carotid or Vertebral Arteries

PURPOSE

To analyze the angiographic and clinical results of transarterial embolization with Onyx (Medtronic-Covidien, Irvine, CA) in dural arteriovenous fistulas (DAVFs) partially fed by arteries arising from the carotid siphon or the vertebral arteries.

METHODS

We isolated 40 DAVFs supplied by either the tentorial artery of the internal carotid artery (ICA) or the posterior meningeal artery of the vertebral artery. These DAVFs were embolized with Onyx through the middle meningeal artery or the occipital artery. We reviewed the occurrence of reflux into the arteries of carotid or vertebral origin.

RESULTS

In all the cases, reflux occurred into the first millimeters of the DAVF arterial feeders arising from carotid or vertebral arteries but slowly enough to be controlled by interruption of Onyx injection. Reflux was always minimal and Onyx never reached the ostium of the arteries. No cerebral ischemic complications occurred in our series.

CONCLUSION

The behavior of Onyx is clearly different from that of cyanoacrylate glue, resulting in superior control during injection. Reflux into arteries arising from the ICA or vertebral artery during DAVF treatment always carries a risk of unintentional non-target embolization of normal cerebral vasculature but Onyx appears to be safe in this situation.

Transarterial Onyx Embolization of Intracranial Dural Fistulas: A Prospective Cohort, Systematic Review, and Meta-Analysis

BACKGROUND

Onyx is important embolic material in the endovascular treatment of intracranial dural arteriovenous fistula (DAVF). However, its impact on DAVF occlusion rates, morbidity, mortality, and complication rates is not fully examined.

OBJECTIVE

To improve understanding of safety and effectiveness profiles associated with transarterial endovascular treatment using Onyx for intracranial DAVF

METHODS

We analyzed data from our prospective clinical registry and conducted a systematic review of all previous transarterial embolization studies using Onyx published between January 2005 and December 2015 in MEDLINE and EMBASE.

RESULTS

In the prospective study, 41 transarterial procedures were performed in 33 consecutive patients harboring 36 DAVFs. Complete initial exclusion was obtained in 32 of 36 (88.9%) fistulas; 31 fistulas were followed up showing 4 (12.9%) recurrences. Procedure-related morbidity and mortality were 3% and 0%, respectively. The literature review identified 19 studies involving a total of 425 patients with 463 DAVFs. Meta-analysis, including our registry data, showed an initial complete occlusion rate of 82% (95% confidence interval [CI]: 74%, 88%; I2, 70.6%), and recurrence rate at midterm of 2% (95% CI: 0%, 5%; I2, 21.5%). Pooled postoperative neurological deficit, procedure-related morbidity, and mortality rates were 4% (95% CI: 2%, 6%; I2, 0%), 3% (95% CI: 1%, 5%; I2, 0%), and 0%, respectively.

CONCLUSION

This meta-analysis suggests that transarterial embolization with Onyx is a safe treatment modality for DAVFs. Although Onyx showed a low recurrence rate at midterm, the long-term risk is poorly addressed in our study and should warrant a longer follow-up.

A hemorrhagic complication after Onyx embolization of a tentorial dural arteriovenous fistula: A caution about subdural extension with pial arterial supply

We report a case of tentorial dural arteriovenous fistula (DAVF) with a severe intracranial hemorrhage occurring after Onyx embolization. A 40-year-old man presented with an asymptomatic tentorial DAVF on angiography. Transarterial embolization with Onyx was performed via the middle meningeal artery, and the cast filled the fistula itself and its proximal draining vein. Postoperative angiography confirmed complete occlusion of the DAVF. A computed tomography scan performed immediately after the procedure demonstrated an acute subdural hematoma with the temporal hemorrhage. Emergency craniotomy revealed continuous arterial bleeding from a viable glomus-like vascular structure around the proximal part of the embolized draining vein, fed by a pial artery arising from the posterior cerebral artery. Pathologic findings suggested diagnosis of vascular malformation extending into the subdural space. Tentorial DAVFs can extend to the subdural space along their drainage route, and may be involved in severe hemorrhagic complications of curative endovascular treatment using Onyx, particularly those with pial arterial supply.

Clinical and Anatomic Insights From a Series of Ethmoidal Dural Arteriovenous Fistulas at Barrow Neurological Institute

BACKGROUND

Ethmoidal dural arteriovenous fistulas (dAVFs) have a malignant natural history and an anatomy that make endovascular therapy challenging. Their uniqueness begs for stratified analyses, but this has largely been precluded by their rarity. We sought to summarize the anatomic, presentation, treatment approaches, and clinical outcomes of patients with these lesions.

METHODS

We reviewed our prospectively maintained institutional database to identify patients diagnosed with ethmoidal dAVFs from January 1, 2000, to December 31, 2015. We evaluated demographic, presentation, angiographic, treatment, and follow-up data.

RESULTS

In total, 27 patients with ethmoidal dAVFs underwent endovascular and/or surgical treatment. Mean patient age was 62 years old and there was a male sex predilection (67% men; 2:1 male-female ratio). All dAVFs exhibited direct cortical venous drainage; venous ectasia was present in 59% of cases. Of the dAVFs, 30% drained posteriorly into the basal vein of Rosenthal or the sylvian veins. Embolization with casting of the draining vein was successful in 2 of 9 cases (22%), including 1 successful transvenous case. There were no clinical or permanent complications from embolization; specifically, no patients experienced visual loss after treatment. Surgical treatment with successful dAVF obliteration was carried out in 24 of 24 patients (100%). One patient declined surgical treatment after attempted endovascular embolization. There were no permanent complications after surgical treatment and no cases of wound infection or cerebrospinal fluid leakage.

CONCLUSIONS

Surgical disconnection remains the gold standard in the treatment of ethmoidal dAVFs. Embolization is a consideration for well-selected cases with favorable arterial or venous access anatomy.

Outcome of microsurgical excision of unruptured brain arteriovenous malformations in ARUBA-eligible patients

OBJECTIVES

To determine the outcome of microsurgical excision of selected unruptured brain arteriovenous malformations (AVMs), and to compare the results with those of the ARUBA trial.

METHODS

Prospective data collection for all patients undergoing microsurgical excision of unruptured brain AVMs by two neurovascular surgeons. Outcome measures similar to those assessed in the ARUBA trial (death and stroke) as well as modified Rankin scores (mRS) at 6 months were assessed.

RESULTS

Between September 2004 and September 2014, 45 patients with unruptured brain AVMs underwent microsurgical excision. 11 patients (eight children and three with mRS >2 at presentation) were excluded to match ARUBA eligibility criteria. 34 patients were included in this study. AVM characteristics closely matched those in the ARUBA trial with 70.5% Spetzler-Martin (SM) grade I or II AVMs, 68% AVM size <3 cm. However, compared to ARUBA, a larger proportion of our patients presented with seizures, and a lower proportion with headaches. 8(23%) had preoperative embolization. There were no deaths and no strokes (as defined in ARUBA). 5 (14.7%) had permanent neurological deficit related to surgery within/near eloquent cortex. At 6 months follow-up, 32 (94%) had mRS score of 0-1. Two (6%) had mRS 2 and none had mRS> 2. Postoperative digital DSA confirmed complete AVM excision in all cases. None of the patients have suffered intracranial hemorrhage during the follow-up period of 6-126 (median 69) months.

CONCLUSIONS

Microsurgical excision of unruptured brain AVMs can be performed with low morbidity in selected cases. Our study has limitations particularly the small number of patients with selected AVMs for microsurgical excision. However, our results suggest that ARUBA results may not be applicable to microsurgical excision when cases are appropriately selected for this treatment modality.

Modified pressure cooker technique: An easier way to control onyx reflux

The use of onyx enabled the treatment of various intracranial vascular diseases more effectively than cyanoacrylate. The pressure cooker technique allowed definitive control of reflux and was made possible via detachable microcatheters. We present a variation of this technique called the modified pressure cooker to make reflux control easier and more reproducible and thus simplifying the procedure. We also extended the application of the technique to other diseases beyond arteriovenous malformations including dural arteriovenous fistulas and hypervascular tumors.

Onyx versus nBCA and coils in the treatment of intracranial dural arteriovenous fistulas

BACKGROUND AND PURPOSE

Intracranial dural arteriovenous fistulas (DAVFs) with cortical venous drainage have significant morbidity and mortality. Complete closure of these lesions is necessary to reduce these risks. The purpose of our study was to compare the outcome of DAVFs treated with Onyx versus those treated with n-Butyl Cyanoacrylate (nBCA) and coil embolization in a case-control study. Compared with nBCA and coil embolization, we hypothesized that Onyx embolization for DAVF is safer and has a higher chance of complete obliteration, with no need for post-embolization surgery for the DAVF.

MATERIALS AND METHODS

From 1998 to 2015, 29 patients who had DAVFs were treated with endovascular embolization. Of these, 24 patients had imaging available for analysis. Successful closure rates, complications, and procedure time were compared between the embolization techniques.

RESULTS

The chance of not requiring post-embolization surgery with Onyx (81.8%) was significantly higher (p = 0.005) than with nBCA (22.22%). The complication rate with Onyx (9.1%) tended to be lower compared with that of nBCA (22.22%; p = 0.37). Procedural time was not significantly different between Onyx (mean 267 minutes) and nBCA (mean 288 minutes) (p = 0.59). The odds ratio of a DAVF being treated with Onyx and then requiring no follow-up surgery was 17.5 (95% CI 1.97-155.4).

CONCLUSION

Our case-control study suggests that Onyx embolization is superior to nBCA and coil embolization in completely obliterating DAVFs, with higher odds of no post-embolization surgery. We also found that Onyx is safe for embolization of DAVFs, with no associated neurological mortality and morbidity.

Advances in Embolization of bAVMs

Brain AVMs are complex malformations, usually congenital, that need a deep understanding of anatomy and pathophysiology to be safely treated. Nowadays, embolization and radiosurgery are carried out more frequently due to their reduced invasiveness as compared to conventional neurosurgery. This paper aims to describe different and new endovascular approaches that allow the interventionalist to treat almost all the small AVMs and to reduce the nidus of the bigger ones in order to facilitate the surgical or radiosurgical intervention.

An Unusual Case of an Ethmoidal Arteriovenous Fistula Draining Into the Superior Ophthalmic Vein: Technical Case Report

BACKGROUND AND IMPORTANCE

Ethmoidal arteriovenous fistulae (AVF) are uncommon and are characterized by an aggressive clinical course. Typical venous drainage is into the frontal cortical veins. We present the case of a 76-year-old male patient who was found to have a right ethmoidal AVF draining directly into the superior ophthalmic vein (SOV), with no cavernous sinus involvement and an associated SOV aneurysm and was successfully treated using surgical cutdown of the SOV followed by endovascular embolization.

CLINICAL PRESENTATION

A 76-year-old man presented with chemosis, proptosis, and lid lag with occasional diplopia. Based on the clinical presentation, there was a suspicion of a carotid cavernous fistula. Cerebral angiography demonstrated a right ethmoidal to SOV fistula, without any involvement of the cavernous sinus, and a SOV aneurysm. Transarterial embolization of the fistula was attempted but was unsuccessful. An SOV approach was performed using SOV cutdown followed by endovascular embolization of the fistula from a transocular route using coils and Onyx embolic agent. There was complete obliteration of the fistula and associated venous aneurysm. The patient had a remarkable recovery.

CONCLUSION

In rare cases, ethmoidal AVFs can present with an unusual venous drainage. Clinical presentation may be similar to carotid cavernous fistulae, and proper identification of the lesion using an angiogram is essential to guide treatment. In cases in which other approaches fail to treat the fistula, direct surgical exposure of the SOV followed by embolization using coiling and Onyx may be successful in achieving AVF occlusion.

Changing Clinical and Therapeutic Trends in Tentorial Dural Arteriovenous Fistulas: A Systematic Review

BACKGROUND AND PURPOSE

Tentorial dural arteriovenous fistulas are characterized by a high hemorrhagic risk. We evaluated trends in outcomes and management of tentorial dural arteriovenous fistulas and performed a meta-analysis evaluating clinical and angiographic outcomes by treatment technique.

MATERIALS AND METHODS

We performed a comprehensive literature search for studies on surgical and endovascular treatment of tentorial dural arteriovenous fistulas. We compared the proportion of patients undergoing endovascular, surgical, and combined endovascular/surgical management; the proportion of patients presenting with ruptured tentorial dural arteriovenous fistulas; and proportion of patients with good neurologic outcome across 3 time periods: 1980-1995, 1996-2005, and 2006-2014. We performed a random-effects meta-analysis, evaluating the rates of occlusion, long-term good neurologic outcome, perioperative morbidity, and resolution of symptoms for the 3 treatment modalities.

RESULTS

Twenty-nine studies with 274 patients were included. The proportion of patients treated with surgical treatment alone decreased from 38.7% to 20.4% between 1980-1995 and 2006-2014. The proportion of patients treated with endovascular therapy alone increased from 16.1% to 48.0%. The proportion of patients presenting with ruptured tentorial dural arteriovenous fistulas decreased from 64.4% to 43.6%. The rate of good neurologic outcome increased from 80.7% to 92.9%. Complete occlusion rates were highest for patients receiving multimodality treatment (84.0%; 95% CI, 72.0%-91.0%) and lowest for endovascular treatment (71.0%; 95% CI, 56.0%-83.0%; P < .01). Long-term good neurologic outcome was highest in the endovascular group (89.0%; 95% CI, 80.0%-95.0%) and lowest for the surgical group (73.0%; 95% CI, 51.0%-87.0%; P = .03).

CONCLUSIONS

Patients with tentorial dural arteriovenous fistulas are increasingly presenting with unruptured lesions, being treated endovascularly, and experiencing higher rates of good neurologic outcomes. Endovascular treatment was associated with superior neurologic outcomes but lower occlusion rates.

Balloon-assisted microcatheter navigation for AVM embolization: technical note

Recurrent feeders may preclude a successful arterial catheterization of arteriovenous malformations (AVMs). In this paper, the authors report their experience with the use of a compliant balloon to assist the microcatheter navigation in AVMs supplied by feeders with recurrent configuration. Eight patients with AVMs supplied by recurrent feeders had unsuccessful microcatheter navigation after multiple attempts to catheterize the pedicle. A compliant balloon was inflated in the parent artery immediately after the origin of the feeder. The microcatheter was then advanced over the wire while the balloon provided support for the navigation. Distal access close to the nidus was achieved in all cases. Anatomical cure was documented in 75% cases. There were no arterial perforations or thromboembolic events. The described technique is a straightforward method for providing support to microcatheter navigation in certain cases of cerebral AVMs supplied by recurrent arterial feeders. This simple yet effective maneuver may enhance outcomes of AVM embolization by eliminating the need for excessive attempts of catheterization.

Stereotactic radiosurgery for arteriovenous malformations after Onyx embolization: a case-control study

OBJECT

Onyx, an ethylene-vinyl alcohol copolymer mixed in a dimethyl sulfoxide solvent, is currently one of the most widely used liquid materials for embolization of intracranial arteriovenous malformations (AVMs). The goal of this study was to define the risks and benefits of stereotactic radiosurgery (SRS) for patients who have previously undergone partial AVM embolization with Onyx.

METHODS

Among a consecutive series of 199 patients who underwent SRS between January 2007 and December 2012 at the University of Virginia, 25 patients had Onyx embolization prior to SRS (the embolization group). To analyze the obliteration rates and complications, 50 patients who underwent SRS without prior embolization (the no-embolization group) were matched by propensity score method. The matched variables included age, sex, nidus volume before SRS, margin dose, Spetzler-Martin grade, Virginia Radiosurgery AVM Scale score, and median imaging follow-up period.

RESULTS

After Onyx embolization, 18 AVMs were reduced in size. Total obliteration was achieved in 6 cases (24%) at a median of 27.5 months after SRS. In the no-embolization group, total obliteration was achieved in 20 patients (40%) at a median of 22.4 months after SRS. Kaplan-Meier analysis demonstrated obliteration rates of 17.7% and 34.1% in the embolization group at 2 and 4 years, respectively. In the no-embolization group, the corresponding obliteration rates were 27.0% and 55.9%. The between-groups difference in obliteration rates after SRS did not achieve statistical significance. The difference in complications, including adverse radiation effects, hemorrhage episodes, seizure control, and patient mortality also did not reach statistical significance.

CONCLUSIONS

Onyx embolization can effectively reduce the size of many AVMs. This case-control study did not show any statistically significant difference in the rates of embolization or complications after SRS in patients who had previously undergone Onyx embolization and those who had not.

Efficacy and limitations of transarterial acrylic glue embolization for intracranial dural arteriovenous fistulas

The efficacy and limitations of transarterial acrylic glue embolization for the treatment of intracranial dural arteriovenous fistulas (DAVFs) were investigated. Thirty-four DAVFs treated by transarterial embolization using n-butyl cyanoacrylate were retrospectively reviewed. The locations of DAVFs were the transverse-sigmoid sinus in 11, tentorium in 10, cranial vault in 9, and superior sagittal sinus, jugular bulb, foramen magnum, and middle cranial fossa in 1 each. Borden classification was type I in 7, type II in 3, and type III in 24. Eight patients had undergone prior transvenous coil embolization. Complete obliteration rate was 56% immediately after embolization, 71% at follow-up angiography, and 85% after additional treatments (1 transvenous embolization and 4 direct surgery). Complications occurred in three patients, consisting of asymptomatic vessel perforations during cannulation in two patients and leakage of contrast medium resulting in medullary infarction in one patient. Transarterial glue embolization is highly effective for Borden type III DAVF with direct cortical venous drainage, but has limitations for Borden type I and II DAVFs in which the affected sinus is part of the normal venous circulation. Onyx is a new liquid embolic material and is becoming the treatment of choice for DAVF. The benefits of glue embolization compared to Onyx embolization are high thrombogenicity, and relatively low risks of cranial nerve palsies and of excessive migration into the draining veins of high flow fistula. Transarterial glue embolization continues to be useful for selected patients, and complete cure can be expected in most patients with fewer complications if combined with transvenous embolization or direct surgery.

Endovascular treatment of intracranial dural arteriovenous fistulas

Endovascular treatment options for dural arteriovenous fistulas (DAVFs) have vastly expanded and become progressively safer in the last several years. Angiographic imaging systems have improved, catheter technology has advanced, and liquid embolic and coil options have increased. As a likely result, an increasing proportion of DAVFs are treated via an endovascular approach. In addition to allowing physicians to appreciate and treat lesions better, varied approaches have been developed. The "plug and push" technique and the new availability of dimethyl sulfoxide--compatible dual lumen balloons have allowed safer and more thorough transarterial treatments. Transvenous treatment has proved to be a valuable technique for some lesions. Hybrid approaches with surgical assisted access to vascular structures have been successfully used to treat more challenging fistulas.

Curing arteriovenous malformations using embolization

Endovascular embolization is typically reserved as an adjuvant therapy in the management of cerebral arteriovenous malformations (AVMs), either for preoperative devascularization or preradiosurgical volume reduction. Curative embolization plays a limited role in AVM treatment but several studies have shown that it is possible, especially with later-generation liquid embolic agents. Given the complexity of AVM anatomy and the recent controversies over the role of any intervention in AVM management, it is critical that the cerebrovascular community better define the indications of each treatment modality to provide quality AVM management. In this review, the authors evaluate the role of curative AVM embolization. Important considerations in the feasibility of curative AVM embolization include whether it can be performed reliably and safely, and whether it is a durable cure. Studies over the past 20 years have begun to define the anatomical factors that are amenable to complete endovascular occlusion, including size, feeding artery anatomy, AVM morphology, and endovascular accessibility. More recent studies have shown that highly selected patients with AVMs can be treated with curative intent, leading to occlusion rates as high as 100% of such prospectively identified lesions with minimal morbidity. Advances in endovascular technology and techniques that support the efficacy and safety of curative embolization are discussed, as is the importance of superselective diagnostic angiography. Finally, the durability of curative embolization is analyzed. Overall, while still unproven, endovascular embolization has the potential to be a safe, effective, and durable curative treatment for select AVMs, broadening the armamentarium with which one can treat this disease.

Management of intracranial aneurysms associated with arteriovenous malformations

Intracranial or brain arteriovenous malformations (BAVMs) are some of the most interesting and challenging lesions treated by the cerebrovascular neurosurgeon. It is generally believed that the combination of BAVMs and intracranial aneurysms (IAs) is associated with higher hemorrhage rates at presentation and higher rehemorrhage rates and thus with a more aggressive course and natural history. There is wide variation in the literature on the prevalence of BAVM-associated aneurysms (range 2.7%–58%), with 10%–20% being most often cited in the largest case series. The risk of intracranial hemorrhage in patients with unruptured BAVMs and coexisting IAs has been reported to be 7% annually, compared with 2%–4% annually for those with BAVM alone. Several different classification systems have been applied in an attempt to better understand the natural history of this combination of lesions and implications for treatment. Independent of the classification used, it is clear that a few subtypes of aneurysms have a direct hemodynamic correlation with the BAVM itself. This is exemplified by the fact that the presence of a distal flow-related or an intranidal aneurysm appears to be associated with an increased hemorrhage risk, when compared with an aneurysm located on a vessel with no direct supply to the BAVM nidus. Debate still exists regarding the etiology of the association between those two vascular lesions, the subsequent implications for patients’ risk of hemorrhagic stroke, and finally the determination of which patients warrant treatment and when. The ultimate goals of the treatment of a BAVM associated with an IA are to prevent hemorrhage, avoid stepwise neurological deterioration, and eliminate the mortality risk associated with recurrent hemorrhagic events. The treatment is only justifiable if the risks associated with an intervention are lower than or equivalent to the long-term risks of disability or mortality caused by the lesion itself. When faced with this difficult decision, a few questions need to be answered by the treating neu-rosurgeon: What is the mode of presentation? What is the symptomatic lesion? Which one of the lesions bled? What is the relationship between the BAVM and IA? Is it possible to safely treat both BAVM and IA? The objective of this review is to discuss the demographics, natural history, classification, and strategies for management of BAVMs associated with IAs.

Transarterial onyx embolization of cranial dural arteriovenous fistulas: long-term follow-up

BACKGROUND AND PURPOSE

Endovascular therapy with liquid embolic agents is a common treatment strategy for cranial dural arteriovenous fistulas. This study evaluated the long-term effectiveness of transarterial Onyx as the single embolic agent for curative embolization of noncavernous cranial dural arteriovenous fistulas.

MATERIALS AND METHODS

We performed a retrospective review of 40 consecutive patients with 41 cranial dural arteriovenous fistulas treated between March 2006 and June 2012 by using transarterial Onyx embolization with intent to cure. The mean age was 57 years; one-third presented with intracranial hemorrhage. Most (85%) had cortical venous drainage. Once angiographic cure was achieved, long-term treatment effectiveness was assessed with DSA and clinical follow-up.

RESULTS

Forty-nine embolization sessions were performed; 85% of cranial dural arteriovenous fistulas were treated in a single session. The immediate angiographic cure rate was 95%. The permanent neurologic complication rate was 2% (mild facial palsy). Thirty-five of the 38 patients with initial cure underwent short-term follow-up DSA (median, 4 months). The short-term recurrence rate was only 6% (2/35). All patients with occlusion at short-term DSA undergoing long-term DSA (median, 28 months) had durable occlusion. No patient with long-term clinical follow-up (total, 117 patient-years; median, 45 months) experienced hemorrhage.

CONCLUSIONS

Transarterial embolization with Onyx as the single embolic agent results in durable long-term cure of noncavernous cranial dural arteriovenous fistulas. Recurrence rates are low on short-term follow-up, and all patients with angiographic occlusion on short-term DSA follow-up have experienced a durable long-term cure. Thus, angiographic cure should be defined at short-term follow-up angiography instead of at the end of the final embolization session. Finally, long-term DSA follow-up may not be necessary if occlusion is demonstrated on short-term angiographic follow-up.

Marginal sinus fistula supplied exclusively by vertebral artery feeders

A 54-year-old woman is reported with severe pulsatile tinnitus. Digital subtraction angiography demonstrated dural arteriovenous fistula of the marginal sinus with feeders arising exclusively from bilateral vertebral arteries. Patient underwent successful transarterial Onyx embolization with complete angiographic and clinical cure.