Cranial dural arteriovenous fistula: transarterial Onyx embolization experience and technical nuances

Endovascular Drug Delivery

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Copolymer liquid embolization of dural arteriovenous fistulas: A 20-year single-center experience

BACKGROUND AND PURPOSE

Dural arteriovenous fistulas (DAVFs) with cortical venous drainage (CVD) carry significant risks of cerebral ischemia and intracranial hemorrhage. Endovascular treatment (EVT) using Onyx, a copolymer-based liquid embolic material, has become the preferred approach. However, the optimal treatment strategy for anterior cranial fossa DAVFs remains debated.

METHODS

This retrospective study analyzed outcomes of EVT for DAVFs in a single center from 2002 to 2023. Patient data including demographics, clinical status, angiographic findings, embolization techniques, and outcomes were recorded. The results of the anterior fossa malformations were analyzed separately afterward.

RESULTS

A total of 195 DAVFs were included in the study. The most common presenting symptom was hemorrhage (41%), most fistulas were located in the transverse and sigmoid sinus region (48%), and the majority of DAVFs had direct CVD (78%). Transarterial embolization with Onyx was the preferred treatment strategy in majority of cases (92%). Overall, 94% of patients showed improvement or stability on the modified Rankin Scale. Two patients died due to rebleeding after partial DAVF embolization. Onyx demonstrated higher immediate complete occlusion rate compared to other embolic materials (88% vs. 35%). Overall, 91% of fistulas were closed at the last follow-up. Ten anterior fossa DAVFs were treated, resulting in clinical improvement and complete occlusion in all cases.

CONCLUSION

Based on the results of our study, we believe that a cure of DAVFs, including those in the anterior fossa, can be achieved in more than 90% of cases through transarterial Onyx embolization, given long-term clinical experience.

Transarterial embolization and transvenous embolization for transverse-sigmoid sinus dural arteriovenous fistulas with cortical venous reflux: A comparative study

BACKGROUND

Dural arteriovenous fistulas (DAVFs) with cortical venous reflux (CVR) carry a high risk for neurological sequelae or death. Recently, transverse-sigmoid sinus DAVFs were shown as good indications for transarterial embolization (TAE) with ONYX. Here, we compared the effectiveness and safety of conventional transvenous embolization (TVE) with those of TAE with ONYX for transverse-sigmoid sinus DAVFs with CVR.

METHODS

Sixty-one patients with transverse-sigmoid sinus DAVFs were treated from April 2013 to May 2020. Among them, 37 patients with CVR were included. Transarterial embolization and TVE were compared in terms of complete occlusion and residual CVR immediately after treatment, complications with worsening modified Rankin Scale (mRS) ≥ 1, amount of contrast media used during treatment, radiation exposure, and surgical procedure time.

RESULTS

Ten patients were treated with 10 TAEs using ONYX and 27 patients with 29 TVEs. Transarterial embolization and TVE showed no differences in the overall complete occlusion rate (80% [8/10 patients] vs. 80% [23/27], respectively), whereas the residual rate of existing CVR was 10% (1/10 patient) vs. 3.4% (1/27) in the TAE and TVE groups, respectively. No complications with worsening mRS ≥1 occurred in either group. Among the parameters of amount of contrast media, radiation dose, and operative time, only radiation dose in the TAE group was lower than that in the TVE group (median: 2239 mGy vs. 3268 mGy, respectively; p = 0.07).

CONCLUSION

For transverse-sigmoid sinus DAVFs with CVR, TAE treatment reduced radiation exposure. However, both TAE and TVE achieved high complete occlusion rates and low complication rates.

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.

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.

Recurrence after cure in cranial dural arteriovenous fistulas: a collaborative effort by the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR)

OBJECTIVE

Cranial dural arteriovenous fistulas (dAVFs) are often treated with endovascular therapy, but occasionally a multimodality approach including surgery and/or radiosurgery is utilized. Recurrence after an initial angiographic cure has been reported, with estimated rates ranging from 2% to 14.3%, but few risk factors have been identified. The objective of this study was to identify risk factors associated with recurrence of dAVF after putative cure.

METHODS

The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) data were retrospectively reviewed. All patients with angiographic cure after treatment and subsequent angiographic follow-up were included. The primary outcome was recurrence, with risk factor analysis. Secondary outcomes included clinical outcomes, morbidity, and mortality associated with recurrence. Risk factor analysis was performed comparing the group of patients who experienced recurrence with those with durable cure (regardless of multiple recurrences). Time-to-event analysis was performed using all collective recurrence events (multiple per patients in some cases).

RESULTS

Of the 1077 patients included in the primary CONDOR data set, 457 met inclusion criteria. A total of 32 patients (7%) experienced 34 events of recurrence at a mean of 368.7 days (median 192 days). The recurrence rate was 4.5% overall. Kaplan-Meier analysis predicted long-term recurrence rates approaching 11% at 3 years. Grade III dAVFs treated with endovascular therapy were statistically significantly more likely to experience recurrence than those treated surgically (13.3% vs 0%, p = 0.0001). Tentorial location, cortical venous drainage, and deep cerebral venous drainage were all risk factors for recurrence. Endovascular intervention and radiosurgery were associated with recurrence. Six recurrences were symptomatic, including 2 with hemorrhage, 3 with nonhemorrhagic neurological deficit, and 1 with progressive flow-related symptoms (decreased vision).

CONCLUSIONS

Recurrence of dAVFs after putative cure can occur after endovascular treatment. Risk factors include tentorial location, cortical venous drainage, and deep cerebral drainage. Multimodality therapy can be used to achieve cure after recurrence. A delayed long-term angiographic evaluation (at least 1 year from cure) may be warranted, especially in cases with risk factors for recurrence.

Endovascular Management of Intracranial Dural Arteriovenous Fistulas: Transarterial Approach

In this second of 3 review articles on the endovascular management of intracranial dural AVFs, we discuss transarterial treatment approaches. The treatment goal is to occlude the fistulous point, including the most distal portion of the arterial supply together with the most proximal portion of the draining vein (ie, the "foot" of the vein), which can be accomplished with liquid embolic agents via transarterial access. Anatomic factors to consider when assessing the safety and efficacy of a transarterial approach using liquid embolic agents include location, angioarchitecture, and proximity of arterial feeders to both the vasa nervosum of adjacent cranial nerves and the external carotid-internal carotid/vertebral artery anastomoses. Anatomic locations typically favorable for transarterial approaches include but are not limited to the transverse/sigmoid sinus, cerebral convexity, and superior sagittal sinus. In this review article, we discuss the technical approaches, outcomes, potential complications, and complication avoidance strategies for transarterial embolization.

Contemporary Management of Cranial Dural Arteriovenous Fistulas

Cranial dural arteriovenous fistulas (dAVFs) are rare acquired neurovascular disorders that have the potential to profoundly alter the local and global cerebral venous drainage. Factors such as location, angioarchitecture, degree of shunting, and mode of presentation all appear to have some bearing on the natural history of dAVFs, which can vary from almost entirely benign to life-threatening. Accurate and evidence-based risk stratification is, therefore, key to informing important management decisions. The treatment strategies are nuanced and, for an already rare entity, can vary tremendously from 1 fistula to another. It is only through a thorough understanding of their behavior and the treatment options available that we will be able to deliver tailored treatment to the correct dAVF and the correct patient. We aimed to provide an up-to-date summary of the reported data on the natural history and predictors of aggressive behavior for cranial dAVFs in general, followed by site-specific management considerations.

Endovascular embolization of high-grade cerebral dural arteriovenous fistulas - assessment of long-term recurrences

INTRODUCTION

Endovascular therapy has shown to be safe and effective for the treatment of cerebral dural arteriovenous fistulas; however, recurrence after complete occlusion is not uncommon, and the timing of recurrence remains unknown.

METHODS

A retrospective single-center cohort study was conducted from January 2005 to December 2020. Patients with high-grade (≥Borden II-Cognard IIB) dural arteriovenous fistulas treated with endovascular therapy were included in this study. Clinical and angiographic characteristics were collected for hospitalization and at follow-up.

RESULTS

A total of 51 patients with a median age of 61 years were studied; 57% were female. High-flow symptoms related to the high-flow fistula were the most common presentation (67%), and 24% presented with intracranial hemorrhage. Transverse-sigmoid (26%) and cavernous (26%) sinuses were the most common dural arteriovenous fistula locations. A total of 40 patients (70%) had middle meningeal arterial feeders and 4 (7%) had deep cerebral venous drainage. The mean number of embolization procedures per patient was 1.4. Transarterial access was the most frequent approach (61%). Onyx alone was the most common embolic agent (26%). Complete occlusion rate was achieved in 46 patients (80.1%). Last mean radiographic follow-up time was 26.7 months for all 57 dural arteriovenous fistulas. Dural arteriovenous fistula recurrence after radiographic resolution at last treatment was seen in six cases (6/46, 13.1%). Mean time for recurrence was 15.8 months. Mean time of last clinical follow-up was 46.1 months for the 51 patients (100%). A total of 10 (20%) experienced any procedural complications, among which two (4%) became major thromboembolic events.

CONCLUSION

Endovascular therapy is safe and effective for the treatment of high-grade dural arteriovenous fistulas. Given the significant recurrence rate of embolized dural arteriovenous fistulas even after 2 years, long-term angiographic follow-up might be needed.

Long-term stability of Onyx: is there any indication for repeated angiography after dural arteriovenous fistula embolization?

OBJECTIVE

The natural course of dural arteriovenous fistulas (DAVFs) is unfavorable. Transarterial embolization with Onyx is currently the therapeutic method of choice, although the long-term stability of Onyx has been questioned. The literature reports a significant difference in the recurrence rate after complete DAVF occlusion and lacks larger series with long-term follow-up. The authors present the largest series to date with a long-term follow-up to determine the stability of Onyx, prospectively comparing magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) as follow-up diagnostic methods.

METHODS

Demographics, clinical symptomatology, length of follow-up, diagnostic methods, and angiographic findings of DAVFs were recorded and retrospectively evaluated in 112 patients. A prospective group of 15 patients with more than 5 years of follow-up after complete DAVF occlusion was established. All 15 patients in the prospective group underwent a clinical examination and MRA; 10 of these patients also underwent DSA. The recurrences and the correlation between the two diagnostic methods were evaluated.

RESULTS

Among the 112 patients, 71 were men and 41 were women, with an average age of 60 years. Intracranial hemorrhage (40%) was the most common clinical presentation of DAVF. At the last follow-up, 73% of the patients experienced clinical improvement, 21% remained unchanged, and 6% worsened. Overall, 87.5% of the DAVFs were occluded entirely with endovascular treatment, and 93% of the DAVFs were classified as cured at the last follow-up (i.e., completely embolized DAVFs and DAVFs that thrombosed spontaneously or after Gamma Knife surgery). Two recurrences of DAVFs were recorded in the entire series. Both were first diagnosed by MRA and confirmed with DSA. The mean follow-up was 27.7 months. In the prospective group, a small asymptomatic recurrence was diagnosed. The mean follow-up of the prospective group was 96 months.

CONCLUSIONS

Onyx is a stable embolic material, although recurrence of seemingly completely occluded DAVFs may develop because of postembolization hemodynamic changes that accentuate primarily graphically absent residual fistula. These residuals can be diagnosed with MRA at follow-up. The authors' data suggest that MRA could be sufficient as the follow-up diagnostic method after complete DAVF occlusion with Onyx. However, larger prospective studies on this topic are needed.

Onyx embolization for dural arteriovenous fistulas: a multi-institutional study

BACKGROUND

Although the liquid embolic agent, Onyx, is often the preferred embolic treatment for cerebral dural arteriovenous fistulas (DAVFs), there have only been a limited number of single-center studies to evaluate its performance.

OBJECTIVE

To carry out a multicenter study to determine the predictors of complications, obliteration, and functional outcomes associated with primary Onyx embolization of DAVFs.

METHODS

From the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database, we identified patients who were treated for DAVF with Onyx-only embolization as the primary treatment between 2000 and 2013. Obliteration rate after initial embolization was determined based on the final angiographic run. Factors predictive of complete obliteration, complications, and functional independence were evaluated with multivariate logistic regression models.

RESULTS

A total 146 patients with DAVFs were primarily embolized with Onyx. Mean follow-up was 29 months (range 0-129 months). Complete obliteration was achieved in 80 (55%) patients after initial embolization. Major cerebral complications occurred in six patients (4.1%). At last follow-up, 84% patients were functionally independent. Presence of flow symptoms, age over 65, presence of an occipital artery feeder, and preprocedural home anticoagulation use were predictive of non-obliteration. The transverse-sigmoid sinus junction location was associated with fewer complications, whereas the tentorial location was predictive of poor functional outcomes.

CONCLUSIONS

In this multicenter study, we report satisfactory performance of Onyx as a primary DAVF embolic agent. The tentorium remains a more challenging location for DAVF embolization, whereas DAVFs located at the transverse-sigmoid sinus junction are associated with fewer complications.

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.

Surgical Treatment of Intramedullary Hemangioblastomas: Current State of Problem (Review)

Intramedullary hemangioblastomas (HAB) refer to very rare highly vascularized vascular spinal cord tumors associated with various neurological disorders. Effective HAB therapy to a greater extent depends on diagnostic accuracy and the absence of intra- and postoperative complications.

The present study is a review of publications concerned with modern diagnostic and therapeutic techniques to control spinal HAB. The authors showed that perfusion computed tomography, computed tomographic angiography, and magnetic resonance angiography can be reasonably used for diagnosis and differentiation in a number of HAB due to their high vascularization. Preoperative embolization significantly reducing intraoperative bleeding risks is highly efficient. Some authors recommend this procedure in case of large lesions and high risks of intraoperative bleeding. The review also considered intraoperative imaging of a tumor and its feeding vessels using indocyanine green providing inspectability over the total tumor resection and clear imaging of tumor vascular architecture. The advantages and restrictions of the mentioned procedures were described.

Multiple Dural Arteriovenous Fistulas Manifesting as Progressive Otalgia and Tinnitus and Treated Using a Single Session of Endovascular Embolization

Background

Multiple cranial dural arteriovenous fistulas (dAVFs) are considered to be an uncommon vascular condition. dAVFs usually manifest with vague symptoms, which are related to the site of occurrence of the lesion and present with complex angio-architectural features, which in turn can render treatment procedures difficult. Appropriate treatment that aims to reduce the risk of intracranial bleeding and manage the patient’s symptoms requires a multidisciplinary approach.

Case Presentation

The patient was a 62-year-old man who developed symptoms of progressive right-sided otalgia and tinnitus. Cross-sectional imaging revealed long-standing venous congestion with intracranial hemorrhage in the right parieto-occipital region. Moreover, cerebral angiography demonstrated multiple complex dAVFs at the right transverse sinus-sigmoid sinus (TS-SS) junction, right posterior condylar confluence (PCC), and torcula. Treatment consisted of one session of endovascular treatment, in which transarterial Onyx embolization was used to treat the dVAF at the right TS-SS junction, transvenous coil embolization for the dVAF at the right PCC, and particle embolization for both occipital arteries feeding the torcular dAVF. Postoperative improvement with favorable clinical outcomes was observed at the patient’s last follow-up visit.

Conclusion

Multiple cranial dAVFs are an uncommon vascular lesion, which can present with unusual symptoms such as otalgia. Moreover, a single session of endovascular therapy can treat this lesion, ie, it can improve the patient’s symptoms and provide a beneficial long-term outcome.

Direct Carotid Cavernous Fistulas

A direct carotid cavernous fistula (CCF) is an abnormal shunt between the internal carotid artery (ICA) and the cavernous sinus (CS). Traumatic CCF is the most common type, accounting for up to 75% of all CCFs. For the management of direct CCF, endovascular therapy has become the standard. For successful endovascular therapy, evaluation of the size and location of orifice of the CCF, venous drainage, and tolerance for ICA occlusion on cerebral angiography is necessary. Multi-planner reformatted images of 3D rotation angiography are useful to visualize the fistula and compartments of the CS precisely. Due to the limited commercial availability of detachable balloons, detachable coils have become a widely employed endovascular tool for the treatment of direct CCFs. The advantageous aspects of coil application are their easy retrievability and better control. In the case of large/multiple fistulas, adjunctive techniques, including balloon- and stent-assisted techniques, are often needed to occlude the CCF while preserving the ICA. To avoid cranial nerve palsy related to over-packing of the CS with detachable coils or a detachable balloon, selective embolization of the fistula portion is required. Use of liquid embolic materials and covered stents was recently reported as another adjunctive technique. In cases in which it is impossible to occlude the CCF while preserving the ICA, parent artery occlusion (PAO) is considered. The selection of additional/alternative techniques and devices depends on the anatomy and hemodynamics of each CCF, and the skill and experience of individual operators.

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.

Endovascular treatment of cerebral dural arteriovenous fistulas with SQUID 12

BACKGROUND

Endovascular therapy with liquid embolic agents (LEAs) is the gold standard for the treatment of cerebral dural arteriovenous fistulas (cDAVFs). The aim of the study is to retrospectively evaluate effectiveness, safety, and midterm follow-up results of endovascular treatment of cDAVFs using SQUID 12.

METHODS

Between June 2017 and January 2020 the authors retrospectively reviewed clinical, demographic and embolization data of 19 consecutive patients with cDAVF who underwent embolization using SQUID 12. The number of arteries catheterized for each procedure, the total amount of embolic agent, the occlusion rate, the injection time, any technical and/or clinical complications were recorded. Mid-term follow-up with DSA was reviewed.

RESULTS

20 procedures were performed in 19 patients. A transarterial approach was accomplished in 19 procedure; a combined transvenous-transarterial approach was realized in 1 treatment. The average time of injection was 33 minutes (2-82 minutes), and the average amount of SQUID 12 was 2.8 mL (0.5-6 mL). Complete angiographic cure at the end of the procedure was achieved in 17 patients. No major periprocedural adverse events were recorded. Mid-term follow-up was achieved in 15 out of 19 patients and confirmed complete occlusion of the cDAVFs in 13/15 patients (87%); in 2 of the initially cured patients a small relapse was detected.

CONCLUSIONS

The treatment of the cDAVFs using SQUID 12 was effective and safe. The lower viscosity seems to allow an easier penetration of the agent with a high rate of complete occlusion of the cDAVFs.

Endovascular treatment of anterior cranial fossa dural arteriovenous fistula: a multicenter series

PURPOSE

We report a multicenter experience using endovascular embolization as the first line approach for treatment of anterior cranial fossa (ACF) dural arteriovenous fistula (DAVF).

METHODS

All patients with DAVFs located in the anterior cranial fossa who were treated with endovascular technique as a first line approach were included. Demographics, clinical presentation, angioarchitecture, strategy, complications, immediate angiographic, and follow-up results were included in the analysis.

RESULTS

Twenty-three patients met the inclusion criteria (18 male and 5 female). Age ranged from 14 to 79 years (mean 53 years). Twelve patients presented with hemorrhage. Twenty-eight endovascular procedures were performed. The overall immediate angiographic cure rate after endovascular treatment was 82.6% (19/23 patients). The angiographic cure rate of the transvenous strategy was significantly superior to the transarterial strategy (p ≤ 0.001). There was 1 complication in 28 total procedures (3.6%). Angiographic follow-up was available in 21 out of the 23 patients with a mean of 25 months (range 2 to 108 months). In these 21 patients, the DAVF was completely cured in 20 (95%). At last follow-up, all patients had a modified Rankin scale (mRS) 0 to 2.

CONCLUSION

Our experience suggests that endovascular treatment for ACF DAVFs has an acceptable safety profile with high rates of complete occlusion, particularly with transvenous approach. Whenever possible, transvenous approach should be preferred over transarterial approach as first line strategy.

Outcomes After Onyx Embolization as Primary Treatment for Cranial Dural Arteriovenous Fistula in the Past Decade

RATIONALE AND OBJECTIVES

This retrospective single-center study aims to evaluate endovascular therapy (EVT) of cranial dural arteriovenous fistulas (dAVF) with ethylene vinyl alcohol (EVOH) copolymer (Onyx) regarding occlusion rates, complications, and recurrences.

MATERIAL AND METHODS

From January 2008 to April 2018, 75 patients with dAVF (41 men, 34 women; mean age 56 years) underwent EVT with the nonadhesive liquid embolic agent as primary treatment. Patient records and angiograms were reviewed for demographic data, symptoms, fistula type and size, number of EVTs, amount of embolic material, occlusion rates, and recurrences.

RESULTS

Seventy-five patients with dAVFs were primarily embolized with EVOH in 96 EVTs. According to the Merland-Cognard classification the majority of dAVFs treated were type 4 (42.7%), followed by type 2a (18.7%), type 2a+b (17.3%), type 1 (8%), type 2b (5.3%), type 3 (5.3%), and type 5 (2.7%). Complete occlusion (CO) of the dAVF was achieved in 45/75 (60%) of cases after a single EVT and in 58 (77%) patients after one or several EVTs. Seven patients (9%) required additional surgical therapy for CO. Successful treatment was achieved for 70/75 (93%) patients including 10 (13%) patients with residual dAVFs type 1-2a. Recurrence after CO occurred in one (1.3%) patient and four (5.3%) patients remained refractory to therapy with dAVFs type > 2a. Procedure-related permanent morbidity occurred in 4/75 (5.3%) patients.

CONCLUSION

For more than a decade transarterial EVOH embolization has established as the first-line treatment for cranial dAVFs with high cure rates and low rates of complications and recurrences. Additional neurosurgical therapy is rarely required for curative treatment.

Intraosseous Cannulation of a Calvarial Diploic Vein for Embolization of a Symptomatic Dural Arteriovenous Fistula: A Technical Case Report

BACKGROUND AND IMPORTANCE

Dural arteriovenous fistulas (DAVFs) may present unique challenges for treatment depending on the anatomy and pattern of venous drainage. If endovascular techniques are to be employed, the DAVF must be amenable to transvenous or transarterial therapy. When access of peripheral vasculature does not provide a straightforward path, less conventional options may be available. This case highlights a novel, technically simple, and effective approach for the treatment of a subset of DAVFs, with venous drainage through calvarial diploic veins, that would make endovascular treatment otherwise challenging or impossible.

CLINICAL PRESENTATION

We present a case of a 66-yr-old female patient who was diagnosed with a symptomatic DAVF located along the sphenoid ridge with a large intraosseous channel containing the draining vein of the fistula. This lesion was successfully treated with transcranial endovascular embolization via direct intraosseous cannulation of the calvarial diploic vein. This novel approach obviated the need for a full-thickness craniotomy, afforded only minimal bone loss, and preserved the integrity of the dura. A 3-mo follow-up angiogram confirmed complete cure of the DAVF with no residual arteriovenous shunt. At 20 mo postembolization, the patient was symptom free, with no reported neurologic deficits. Complete diagnostic work-up, treatment planning in a multidisciplinary environment, and a novel approach for endovascular embolization utilizing a hybrid operating suite played key roles in the successful implementation of this technique.

CONCLUSION

This is the first report of direct intraosseous cannulation of a calvarial diploic vein for successful transcranial endovascular embolization of a symptomatic DAVF.

Are type I dural arteriovenous fistulas safe? Single-centre experience of endovascular treatment of dural arteriovenous fistulas

Introduction

There are mixed reports on the incidence of intracranial haemorrhage in patients with dural arteriovenous fistulas. We assessed new proposed risk factors (i.a. number of outflows and outflow diameter) of intracerebral haemorrhage due to intracranial dural arteriovenous fistula and presented our personal experience in endovascular treatment of dural arteriovenous fistulas.

Material and methods

The patient database from January 2006 and December 2016 was reviewed, and 25 patients with 28 dural arteriovenous fistulas were identified.

Results

50% of patients presented with intracerebral haemorrhage. Multiple dural fistulas occurred in 12% of patients. Spearman’s rank correlation coefficient revealed that there was a strong association between Cognard classification type and time needed to treat (r = 0.59, p < 0.05), as well as the volume of contrast used (r = 0.77, p < 0.05). Infratentorial (r = 0.53, p < 0.05) and right-sided (r = 0.66, p < 0.05) localisation were more challenging to treat. Bleeding was associated with poorer clinical outcome (r = 0.48, p < 0.05). No significant differences were found between the non-haemorrhagic group and the haemorrhagic group regarding the number of outflows (p = 0.459) and largest outflow diameter (p = 0.298). Clinical evaluation at follow-up was as follows: 56% of patients were asymptomatic, 24% had non-significant disability, maintaining independency, 16% had moderate disability, and 8% died – one in the course of intracerebral haemorrhage and one due to other sustained injuries. There were no reported embolisation-related complications.

Conclusions

To conclude, regardless of presentation, both symptomatic and asymptomatic dural arteriovenous fistulas deserve clinical attention, structured evaluation, and follow-up. Type I fistulas were associated with haemorrhage in 1/3 of all cases. Overall our results indicate that the risk of haemorrhage and dire consequences is multifactorial.

The Application of Copernic RC Balloon in Endovascular Treatment of Complex Intracranial Dural Arteriovenous Fistula of the Transverse Sigmoid Sinus

BACKGROUND

During endovascular treatment of complex intracranial dural arteriovenous fistulas (DAVFs) of the transverse sigmoid sinus, it can be difficult to preserve the patency of the dural sinus. We have described the details of the transvenous balloon-assisted technique using Copernic RC balloon as a treatment option for patients with complex DAVFs of the transverse sigmoid sinus.

CASE DESCRIPTION

In these 2 cases, the Copernic RC balloon was navigated into the internal jugular vein and placed at the distal end of the DAVFs in the transverse sinus. After the balloon was fully inflated, a transarterial glue embolization or transvenous Onyx tunnel technique was performed, with complete exclusion of the fistula and patency of the transverse sigmoid sinus. No immediate or delayed postoperative complications occurred.

CONCLUSION

Transvenous Copernic RC balloon-assisted embolization of DAVFs in the transverse and sigmoid sinuses is safe and can offer complete occlusion of DAVFs and remission of clinical symptoms.

Hybrid Capability to Integrate Multiple Treatment Modalities for Managing High-Grade Intracranial Dural Arteriovenous Fistulas

BACKGROUND

An integrated multimodality approach can be effective in treatment of high-grade dural arteriovenous fistulas. Nevertheless, this requires a high level of efficient cooperation between different departments, underlying a degree of bias in the decisional process. In comparison, hybrid capability, integrating these modalities in one hand, may allow aggregating multimodality treatment strategies by pooling their individual benefits, leading to a more holistic view of the consequences of each modality.

METHODS

We retrospectively reviewed 18 cases of dural arteriovenous fistulas subjected to a hybrid treatment approach at the Diakonieklinikum Jung-Stilling, Siegen, Germany, between March 2008 and January 2017. Nine cases were excluded. We selected 4 cases that highlight different aspects of hybrid capability for illustrative purposes.

RESULTS

Hybrid capability allows treatment of a dural arteriovenous fistula based on the individual clinical situation of the patient and features of the lesion, free of interdepartmental bias. The surgeon maintains a level of flexibility that enables him or her to move from a minimally invasive endovascular approach to a maximally invasive surgical access according to the specific situation. Hybrid capability can lead to a highly efficient treatment regimen with palliation of symptoms and complete obliteration of the fistula, improving performance in these complex pathologies.

CONCLUSIONS

Hybrid capability has great potential in the treatment of complex neurovascular lesions. It remains to be seen if a single surgeon with hybrid capability can supersede the current multidepartmental practice and achieve better outcomes.

Current status of endovascular treatment for dural arteriovenous fistula of the transverse-sigmoid sinus: A literature review

Most intracranial dural arteriovenous fistulae (DAVFs) involve the transverse-sigmoid sinus (TSS), and various types of endovascular treatment (EVT) have been involved in managing TSS DAVFs. A current, comprehensive review of the EVT of TSS DAVFs is lacking. This study used the PubMed database to perform a literature review on TSS DAVFs to increase the current understanding of this condition. For high-grade TSS DAVFs such as Borden type 3, the goal of EVT is curative treatment. However, for low-grade TSS DAVFs such as Borden type 1 and some Borden type 2 TSS DAVFs, symptom relief or elimination of cortical reflux may be sufficient. Currently, EVT has become the first-line treatment for TSS DAVFs, including transarterial embolization (TAE), transvenous embolization (TVE) or both. TAE alone and TSS balloon-assisted TAE are also commonly used. However, TVE for TSS DAVFs is recognized as the most effective treatment, including coil direct packing TSS, Onyx® (ethylene vinyl alcohol copolymer) TVE, and balloon-assisted Onyx® TVE, which are commonly applied. In addition, TSS reconstructive treatment can be an effective procedure to treat TSS DAVFs. EVT is accompanied with complications, including technique- and treatment-related complications. Although complications may occur, TSS DAVFs have an acceptable prognosis after EVT.

Toward a Better Understanding of Dural Arteriovenous Fistula Angioarchitecture: Superselective Transvenous Embolization of a Sigmoid Common Arterial Collector

BACKGROUND AND PURPOSE

Our aim was to propose a conceptually new angioarchitectural model of some dural arteriovenous fistulas based on subset analysis of transverse and sigmoid type lesions. The "common collector" notion argues for convergence of multiple smaller caliber arterial vessels on a common arterial collector vessel within the sinus wall. Communication of this single collector (or constellation of terminal collectors) with the sinus proper defines the site of arteriovenous fistula, which can be closed by highly targeted embolization, preserving the sinus and avoiding unnecessary permeation of indirect arterial feeders.

MATERIALS AND METHODS

One hundred consecutive dural arteriovenous shunts were examined. Thirty-six transverse/sigmoid fistulas were identified within this group and analyzed for the presence of a common arterial collector as well as other parameters, including demographics, grade, treatment approach, and outcome.

RESULTS

A common collector was identified in nearly all Cognard type I lesions (15 fistulas with 14 single collector vessels seen) and progressively less frequently in higher grade fistulas. Identification of the common collector requires careful angiographic analysis, including supraselective and intraprocedural angiographies during treatment, and final embolic material morphology.

CONCLUSIONS

Detailed evaluation of imaging studies allows frequent identification of a vascular channel in the sinus wall, which we argue reflects a compound, common arterial channel (rather than a venous collector) with 1 or several discrete fistulous points between this vessel and the sinus proper. Targeted closure of this channel is often feasible, with sinus preservation and avoidance of embolic material penetration into arteries remote from fistula site.

Unique percutaneous direct puncture technique for occlusion of a hypoglossal canal dural arteriovenous fistula

PURPOSE

To report percutaneous transcranial puncture, embolization and occlusion of a very symptomatic hypoglossal canal/anterior condylar vein dural arteriovenous fistula (DAVF) using syngo iGuide navigational software in a patient in whom transarterial and transvenous embolization and surgery had failed.

METHODS

After unsuccessful arterial and venous embolization and surgical treatment of a symptomatic hypoglossal canal DAVF, a 47-year-old man was transferred for further management. With exquisite anatomic detail provided by C-arm cone-beam computed tomography (CBCT) equipment (Artis zee Biplane, Dyna CT VC21H, Siemens Healthcare GmbH, Germany) and syngo iGuide needle guidance navigational software (Siemens Healthcare GmbHy) for planning a safe direct approach, the hypoglossal/anterior condylar vein, the dominant outflow vein of the fistula, was needle punctured percutaneously at the hypoglossal foramen and occluded with ethylene vinyl alcohol copolymer liquid embolic agent (Onyx, Medtronic, Minneapolis, Minnesota, USA) after placing two anchoring platinum coils (Target detachable coils, Stryker Neurovascular, Fremont, California, USA).

RESULTS

After a year of progressively severe left eye proptosis, chemosis and increased intraocular pressure, the symptoms quickly subsided after this embolization and the patient was symptom free at his 3-month and later checkups.

CONCLUSION

With guidance and imaging provided by CBCT and syngo iGuide navigational software, an otherwise untreatable DAVF was successfully embolized and obliterated by an aggressive unique percutaneous trans-cranial needle puncture of the dominant outflow vein in the hypoglossal canal.

Carotid-cavernous fistula: current concepts in aetiology, investigation, and management

A carotid-cavernous fistula (CCF) is an abnormal communication between arteries and veins within the cavernous sinus and may be classified as either direct or dural. Direct CCFs are characterized by a direct connection between the internal carotid artery (ICA) and the cavernous sinus, whereas dural CCFs result from an indirect connection involving cavernous arterial branches and the cavernous sinus. Direct CCFs frequently are traumatic in origin and also may be caused by rupture of an ICA aneurysm within the cavernous sinus, Ehlers-Danlos syndrome type IV, or iatrogenic intervention. Causes of dural CCFs include hypertension, fibromuscular dysplasia, Ehlers-Danlos type IV, and dissection of the ICA. Evaluation of a suspected CCF often involves non-invasive imaging techniques, including standard tonometry, pneumotonometry, ultrasound, computed tomographic scanning and angiography, and/or magnetic resonance imaging and angiography, but the gold standard for classification and diagnosis remains digital subtraction angiography. When a direct CCF is confirmed, first-line treatment is endovascular intervention, which may be accomplished using detachable balloons, coils, liquid embolic agents, or a combination of these tools. As dural CCFs often resolve spontaneously, low-risk cases may be managed conservatively. When invasive treatment is warranted, endovascular intervention or stereotactic radiosurgery may be performed. Modern endovascular techniques offer the ability to successfully treat CCFs with a low morbidity and virtually no mortality.

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.

Embolization of cranial dural arteriovenous fistulas in the liquid embolic era: A Sydney experience

Endovascular management of dural arteriovenous fistulas has become a mainstay of treatment. In particular, modern techniques have allowed greater fistula penetration and likelihood of complete obliteration. However, the efficacy of newer agents has not been quantified outside of predominantly small case reports and case series. Furthermore, the Australian experience with fistula embolization has yet to be reported in the literature. To this aim, we performed a retrospective review of our endovascular management of a large cohort of cranial dural arteriovenous fistulas in the liquid embolic era. This retrospective case series included ninety-six consecutive patients of any Cognard grade, treated between 2005 and 2016. Liquid embolic agents were used exclusively in eighty-three cases. The overall complete obliteration rate was 89.6% with a residual fistula rate of 2%, and complication rate of 8.3%. This Sydney, Australia cohort demonstrates excellent treatment effect and safety outcomes and thus supports the primary treatment of this condition by endovascular means.

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.

An Onyx tunnel: reconstructive transvenous balloon-assisted Onyx embolization for dural arteriovenous fistula of the transverse-sigmoid sinus

Transvenous embolization is an effective method for treating dural arteriovenous fistulas (DAVFs) of the transverse-sigmoid sinus (TSS). However, in cases of complicated DAVFs, it is difficult to preserve the patency of the dural sinus. The authors describe the technical details of a new reconstructive technique using transvenous balloon-assisted Onyx embolization as another treatment option in a patient with an extensive and complex DAVF of the left TSS. A microcatheter and compliant balloon catheter were navigated into the left internal jugular vein and placed at the distal end of the DAVF in the transverse sinus. The microcatheter was placed between the vessel wall of the TSS and the balloon. After the balloon was fully inflated, Onyx-18 was injected at the periphery of the balloon in a slow, controlled, progressive, stepwise manner; the balloon and microcatheter were simultaneously withdrawn toward the sigmoid sinus, with Onyx encompassing the entirety of the complex DAVF. The Onyx refluxed into multiple arterial feeders in a distal-to-proximal step-by-step manner, ultimately resulting in an Onyx tunnel. The final angiography study revealed complete obliteration of the DAVF and patency of the TSS. The Onyx tunnel, or reconstructive transvenous balloon-assisted Onyx embolization technique, may be an effective treatment option for large, complex DAVFs of the TSS. This technique may provide another option to facilitate the complete obliteration of the DAVF while preserving the functional sinus.

Pial Artery Supply as an Anatomic Risk Factor for Ischemic Stroke in the Treatment of Intracranial Dural Arteriovenous Fistulas

BACKGROUND AND PURPOSE

Although intracranial dural arteriovenous fistulas are principally supplied by dural branches of the external carotid, internal carotid, and vertebral arteries, they can also be fed by pial arteries that supply the brain. We sought to determine the frequency of neurologic deficits following treatment of intracranial dural arteriovenous fistulas with and without pial artery supply.

MATERIALS AND METHODS

One hundred twenty-two consecutive patients who underwent treatment for intracranial dural arteriovenous fistulas at our hospital from 2008 to 2015 were retrospectively reviewed. Patient data were examined for posttreatment neurologic deficits; patients with such deficits were evaluated for imaging evidence of cerebral infarction. Data were analyzed with multivariable logistic regression.

RESULTS

Of 122 treated patients, 29 (23.8%) had dural arteriovenous fistulas with pial artery supply and 93 (76.2%) had dural arteriovenous fistulas without pial arterial supply. Of patients with pial artery supply, 4 (13.8%) had posttreatment neurologic deficits, compared with 2 patients (2.2%) without pial artery supply (P = .04). Imaging confirmed that 3 patients with pial artery supply (10.3%) had cerebral infarcts, compared with only 1 patient without pial artery supply (1.1%, P = .03). Increasing patient age was also positively associated with pial supply and treatment-related complications.

CONCLUSIONS

Patients with dural arteriovenous fistulas supplied by the pial arteries were more likely to experience posttreatment complications, including ischemic strokes, than patients with no pial artery supply. The approach to dural arteriovenous fistula treatment should be made on a case-by-case basis so that the risk of complications can be minimized.

Medial Tentorial Dural Arteriovenous Fistula Embolization: Single Experience with Embolic Liquid Polymer SQUID and Review of the Literature

BACKGROUND

Tentorial dural arteriovenous fistulas (DAVFs) are uncommon, complex fistulas located between the leaves of the tentorium cerebelli with a specific anatomic and clinical presentation characterized by high hemorrhagic risk. We present a rare case of a medial tentorial DAVF successfully managed via transarterial embolization using SQUID liquid polymer.

CASE DESCRIPTION

A 60-year-old woman presented with a history of left progressive hearing loss and tinnitus for >1 year. Cerebral angiography demonstrated the presence of a medial tentorial DAVF with multiple arterial feeders, including the artery of Davidoff and Schechter; reverse venous outflow was observed in the inferior sagittal sinus and in multiple cortical veins. The patient underwent transarterial embolization with SQUID liquid polymer, an embolic agent that provides 2 different viscous formulations to cast the DAVF. The procedure went well without any complication, and the patient regained her preoperative status. In the postprocedural period, the patient experienced complete resolution of tinnitus. At 6 months, she remained asymptomatic, and cerebral angiography confirmed complete, stable occlusion of the fistula and normalization of cerebral deep venous outflow.

CONCLUSIONS

Medial tentorial DAVFs are considered the most complex DAVFs because of their location and extensive vascular supply. Our literature review focused on endovascular treatment of tentorial DAVFs to highlight the usefulness of new embolic agents in management of these diseases. To our knowledge, we report the first successful use of SQUID liquid polymer in management of a tentorial DAVF.

Evaluation of a novel liquid embolic agent (precipitating hydrophobic injectable liquid (PHIL)) in an animal endovascular embolization model

BACKGROUND

The choice of the embolic agent and the embolization technique can have a significant impact on the success of endovascular embolization.

OBJECTIVE

To evaluate a novel iodinated copolymer-based liquid embolic agent (precipitating hydrophobic injectable liquid (PHIL)) in the porcine rete mirabile (RM), serving as an endovascular embolization model. Onyx, as an established liquid embolic agent, served as comparator.

MATERIALS AND METHODS

Sixteen embolization procedures were performed using PHIL (n=8) or Onyx (n=8) as liquid embolic agent. Waiting time between injections was set to 30 or 60 s (n=4 per study group). Survival time after intervention was 2 hours or 7 days. Embolization characteristics (eg, procedure times, number of injections and volume of embolic agent) and embolization extent (percentage of embolized RM in post-interventional x-ray) were assessed. Post-interventional CT and histopathological analyses were performed.

RESULTS

Embolization characteristics and embolization extent were not significantly different for PHIL and Onyx, including subgroups (eg, embolization extent 44% vs 69% (medians); p=0.101). For PHIL, extension of the waiting time from 30 to 60 s led to a significantly higher embolization extent (24% vs 72% (medians); p=0.035). Moderate disintegration and mild inflammation of the embolized blood vessels were present for both embolic agents.

CONCLUSION

PHIL is feasible for transarterial embolization in an acute and subacute endovascular embolization model. In this preliminary experimental in vivo study, embolization characteristics, embolization extent, and biocompatibility seem to be similar to those of Onyx.

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.

Liquid Embolic Agents for Endovascular Embolization: Evaluation of an Established (Onyx) and a Novel (PHIL) Embolic Agent in an In Vitro AVM Model

BACKGROUND AND PURPOSE

Embolization plays a key role in the treatment of arteriovenous malformations. The aim of this study was to evaluate an established (Onyx) and a novel (precipitating hydrophobic injectable liquid [PHIL]) liquid embolic agent in an in vitro AVM model.

MATERIALS AND METHODS

An AVM model was integrated into a circuit system. The artificial nidus (subdivided into 28 honeycomb-like sections) was embolized with Onyx 18 (group Onyx; n = 8) or PHIL 25 (group PHIL; n = 8) with different pause times between the injections (30 and 60 seconds, n = 4 per study group) by using a 1.3F microcatheter. Procedure times, number of injections, embolization success (defined as the number of filled sections of the artificial nidus), volume of embolic agent, and frequency and extent of reflux and draining vein embolization were assessed.

RESULTS

Embolization success was comparable between Onyx and PHIL. Shorter pause times resulted in a significantly higher embolization success for PHIL (median embolization score, 28 versus 18; P = .011). Compared with Onyx, lower volumes of PHIL were required for the same extent of embolization (median volume per section of the artificial nidus, 15.5 versus 3.6 μL; P < .001).

CONCLUSIONS

While the embolization success was comparable for Onyx and PHIL, pause time had a considerable effect on the embolization success in an in vitro AVM model. Compared with Onyx, lower volumes of PHIL were required for the same extent of embolization.

Transarterial Onyx Embolization for Patients with Cavernous Sinus Dural Arteriovenous Fistulas Who Have Failed Transvenous Embolization

Transvenous embolization is the treatment of choice for cavernous sinus dural arteriovenous fistulas (csDAVFs) despite occasional difficulty in transvenous catheterization. We reported our experience in the treatment of csDAVFs by transarterial Onyx embolization in patients who had failed transvenous catheterization. We reviewed the clinical and radiographic records of csDAVFs patients receiving transarterial Onyx embolization after failed transvenous Onyx embolization at our institution over a period of 31 months. Success was defined as complete or near complete occlusion upon angiographic examination. In seven cases, the microcatheter failed to reach the cavernous sinus; in the remaining case, the internal jugular vein was occlusive. Eight sessions of the embolization and catheterization procedures via the arterial routes were conducted. Among them, five cases via the middle meningeal artery and the other three via the accessory meningeal artery. Angiography, immediately after embolization, revealed complete occlusion in seven cases (87.5 %) and partial occlusion in the remaining case. Angiographic follow-up (range, 6-10 months) showed that all patients achieved complete embolization. In cases where transvenous embolization of the cavernous sinus is difficult, transarterial embolization of the fistulas offers a safe and effective alternative.

Double-lumen balloon for Onyx® embolization via extracranial arteries in transverse sigmoid dural arteriovenous fistulas: initial experience

Transverse-sigmoid dural arteriovenous fistulas (TS DAVFs) can be challenging to treat by endovascular means. Indeed, a total cure of the fistula can only be achieved when complete occlusion of the fistulous point(s) is obtained by penetration of the embolic agent. However, in some cases, especially for transosseous branches from extracranial arteries like the occipital artery (OcA) or the superficial temporal artery (STA), such penetration is usually poor, leading to major proximal reflux and incomplete fistula obliteration. We present three cases of embolization in two patients with TS DAVF through the OcA and/or the STA with Onyx® using a double-lumen balloon (Microvention, Tustin, CA, USA). This technique allows the penetration of the embolic agent in the transosseous branches by forming a counter-pressure with the inflated balloon. This technique may be useful to achieve complete occlusion of TS DAVFs by endovascular means.

Evolution of treatment and a detailed analysis of occlusion, recurrence, and clinical outcomes in an endovascular library of 260 dural arteriovenous fistulas

OBJECTIVE Many small series and technical reports chronicle the evolution of endovascular techniques for cranial dural arteriovenous fistulas (dAVFs) over the past 3 decades, but reports of large patient series are lacking. The authors provide a thorough analysis of clinical and angiographic outcomes across a large patient cohort. METHODS The authors reviewed their endovascular database from January 1996 to September 2015 to identify patients harboring cranial dAVFs who were treated initially with endovascular approaches. They extracted demographic, presentation, angiographic, detailed treatment, and long-term follow-up data, and they evaluated natural history, initial angiographic occlusion, complications, recurrence, and symptomatic resolution rates. RESULTS Across a cohort of 251 patients with 260 distinct dAVFs, the overall initial angiographic occlusion rate was 70%; recurrence or occult residual lesions were seen on subsequent angiography in 3% of cases. The overall complication rate was 8%, with permanent neurological complications occurring in 3% of cases. Among 102 patients with dAVFs without cortical venous reflux, rates of resolution/improvement of pulsatile tinnitus and ocular symptoms were 79% and 78%, respectively. Following the introduction of Onyx during the latter half of the study period, the number of treated dAVFs doubled; the initial angiographic occlusion rate increased significantly from 60% before the use of Onyx to 76% after (p = 0.01). In addition, during the latter period compared with the pre-Onyx period, the rate of dAVFs obliterated via a transarterial-only approach was significantly greater (43% vs 23%, p = 0.002), as was the number of dAVFs obliterated via a single arterial pedicle (29% vs 11%, p = 0.002). CONCLUSIONS Overall, in the Onyx era, the rate of initial angiographic occlusion was approximately 80%, as was the rate of meaningful clinical improvement in tinnitus and/or ocular symptoms after initial endovascular treatment of cranial dAVFs.

Middle meningeal artery: Gateway for effective transarterial Onyx embolization of dural arteriovenous fistulas

Curative transarterial embolization of noncavernous sinus dural arteriovenous fistulas (dAVFs) is challenging. We sought to evaluate the role of the middle meningeal artery (MMA) in endovascular treatment of these lesions. We performed a retrospective cohort study on patients who underwent transarterial Onyx embolization of a noncavernous sinus dAVFs with contribution from the MMA at a major academic institution in the United States from January 2009 to January 2015. Twenty consecutive patients who underwent transarterial Onyx embolization of a noncavernous sinus dAVF were identified. One patient was excluded as there was no MMA contribution to the dAVF. All of the remaining 19 patients (61.3 ± 13.8 years of age) underwent transarterial embolization through the MMA. Six patients (31.6%) presented with intraparenchymal or subarachnoid hemorrhage from the dAVF. The overall angiographic cure rate was 73.7% upon last follow up. In 71.4% of successfully treated patients transarterial embolization of the MMA alone was sufficient to achieve angiographic cure. When robust MMA supply was present, MMA embolization resulted in angiographic cure even after embolization of other arterial feeders had failed in 92.9% of patients. A robust contribution of the MMA to the fistula was the single most important predictor for successful embolization (P = 0.00129). We attribute our findings to the fairly straight, non-tortuous course of the MMA that facilitates microcatheter access, navigation, and Onyx penetration. Noncavernous sinus dAVF can be successfully embolized with transarterial Onyx through the MMA, as long as supply is robust. A transvenous approach is rarely necessary. Clin. Anat. 29:718-728, 2016. © 2016 Wiley Periodicals, Inc.

Long-term angiographic results of endovascularly “cured” intracranial dural arteriovenous fistulas

OBJECT

Dural arteriovenous fistulas (DAVFs) are complex lesions consisting of abnormal connections between meningeal arteries and dural venous sinuses and/or cerebral veins. The goal of treatment is surgical or endovascular occlusion of the fistula or fistulous nidus or at least the disconnection of the feeding vessels and the draining veins. Delayed angiographic data on previously embolized dural fistulas is lacking. The authors report their experience and the long-term angiographic results with embolization of intracranial DAVF using Onyx.

METHODS

All cases of DAVF treated primarily with Onyx at the authors’ institution from 2006 to 2013 were retrospectively reviewed. Patient demographics, fistula characteristics, embolization details, and angiographic follow-up were analyzed.

RESULTS

Fifty-eight patients with DAVFs were treated during the study period. Twenty-two patients were treated with open surgery with or without prior embolization. Thirty-six patients were treated with embolization alone, of whom 26 underwent an attempt at curative embolization and are the subject of this review. All but 2 of these patients were treated in a single session. Angiographic “cure” was achieved in all cases following treatment. Follow-up angiography was performed in 21 patients at a mean of 14 months after treatment (range 2–39 months). Asymptomatic angiographic recurrence of the fistula was evident in 3 of the 21 patients (14.3%). On reviewing the procedural angiograms of the cases in which the DAVFs recurred, it was observed that the Onyx cast did not reach the venous portion in 1 case, whereas it did reach the vein in the other 2 cases.

CONCLUSIONS

Recurrence following initial angiographic cure of DAVF is not uncommon. Incomplete penetration of the embolic material into the proximal portion of the venous outlet may lead to delayed recurrence. Long-term angiographic follow-up is highly recommended.

Diagnosis and management of intracranial dural arteriovenous fistulas

Dural arteriovenous fistula (DAVF) is a rare type of acquired intracranial vascular malformation. Recent progress in neuroimaging technology, such as advanced MRI and CT, provides non-invasive methods to accurately diagnose DAVF, including evaluation of the hemodynamics of the drainage veins. The clinical manifestations of DAVFs vary widely and depend on the location and venous drainage pattern of arteriovenous shunting. Patients with high grade DAVFs having cortical venous reflux should receive aggressive treatment to prevent the occurrence of intracranial hemorrhage and other neurological deficits related to venous congestion. Intra-arterial or intravenous endovascular embolization remains the primary therapy for high grade DAVF, while open surgery and stereotactic radiosurgery can serve as alternative treatment options. Early and accurate diagnosis with appropriate treatment is the goal for clinical management of DAVFs to reduce symptoms and prevent the development of venous congestion and stroke.