Endovascular treatment of cranial dural arteriovenous fistulae: a single-centre, 14-year experience and the impact of Onyx on local practise

Quest for the optimal venous access in a complex skull base dural fistula: Case illustrations and principles

Treatment of dural arteriovenous fistulae (DAVFs) is dynamic and evolves between diagnostic and therapeutic angiography.A 79-year-old man with a left jugular foramen DAVF presented with new onset cranial nerve XII palsy. The DAVF progressed from Cognard grade I to IIa + b. A transvenous approach was chosen. Attempts to access the left inferior petrosal sinus (IPS) via the left internal jugular vein failed due to occlusion. An alternative route through the left superior ophthalmic vein and left cavernous sinus to the IPS was devised. Successful coil occlusion of the IPS was achieved. Postoperatively, symptoms resolved, and angiography showed no cortical venous reflux.

Comparing transvenous coiling and transarterial embolization with Onyx/NBCA for cavernous sinus dural arteriovenous fistulas: A retrospective study in a single center

BACKGROUND

Endovascular management is the gold standard for cavernous sinus dural arteriovenous fistulas (CS-dAVFs) in patients with signs of ophthalmoplegia, visual defects, or intolerable clinical symptoms. Although the efficacy of embolization has been confirmed, complications during post-endovascular management have not been compared in a more extensive CS-dAVFs case series. Therefore, we compared the effectiveness and peri-procedural complications of transvenous coiling with those of transarterial embolization (TAE) using liquid embolic agents.

METHODS

We reviewed 71 patients with CS-dAVFs in one medical center from 2005/7 to 2016/7. We performed seventy-seven procedures on 71 patients, including six recurrent cases. We compared the efficacy and peri-procedural complications of transvenous coiling and TAE.

RESULTS

The complete occlusion rate for transvenous coiling was 79.2%, and that for TAE was 75.0%. Findings revealed (1) similar ophthalmoplegia complication rates (p = 0.744); (2) more frequent and permanent CN5 or CN7 neuropathy with liquid embolic agent use (p = 0.031 and 0.028, respectively); and (3) a higher risk of infarction or ICH (p = 0.002 and 0.028, respectively) in response to aggressive TAE.

CONCLUSION

Transvenous cavernous sinus coiling resulted in a similar occlusion rate and lower complication risk than transarterial Onyx/n-butyl cyanoacrylate (NBCA). We can access via an occluded inferior petrosal sinus (even contralateral), and direct transorbital puncture was a safe alternative. TAE with Onyx/NBCA was helpful in cases of oligo-feeders, but multidisciplinary treatment and multi-session TAE were usually needed for patients with multiple feeders and complex fistulas.

Direct Burr Hole Access for Transverse-Sigmoid Junction DAVF Embolization: A Case Report

Dural arteriovenous fistulas (DAVFs) are rare intracranial vascular malformations that present with a variety of clinical signs and symptoms. Among these, intracranial hemorrhage is a severe complication. A 72-year-old male presented with headache and pulsatile tinnitus. Cerebral angiography revealed a Borden II/Cognard IIa+b DAVF. He underwent stage 1 transarterial embolization of the occipital artery which reduced shunting by 30%. Several attempts were made to access the fistula during stage 2 transvenous embolization, but it was not possible to access the left transverse sinus fistula site since there was no communication across the torcula from the right transverse sinus and the left inferior sigmoid-jugular bulb was occluded. Therefore, a single burr hole was drilled and direct access to the DAVF was achieved with a micropuncture needle under neuronavigational guidance. The left transverse-sigmoid sinus junction was then embolized with coils. After the procedure, angiography revealed that the DAVF was cured with no residual shunting. This case demonstrates how minimally invasive surgery provides an alternative method to access a DVAF when conventional transarterial and/or transvenous embolization treatment options are not possible. Each DAVF case has unique anatomy and physiology, and creative multi-disciplinary strategies can often yield the best results.

Surgical Treatment of Dural Arteriovenous Fistula: A Case Report and Literature Review

Dural arteriovenous fistulas (dAVF) are rare, acquired intracranial arteriovenous malformations consisting of a pathological shunt located within the intracranial dura matter. The etiology of dAVFs remains unclear, but current thought suggests that these lesions are associated with thrombosis of the dural sinuses and other intracranial veins. dAVF’s with severe symptomatology or high-risk angioarchitecture should be treated without delay, and endovascular repair is generally accepted as the first-line treatment. Both transarterial and transvenous approaches can be used to cure dAVFs. Surgery and stereotactic radiosurgery may also be used when endovascular approaches are unsuccessful or not feasible. Some studies, however, have shown that surgery for dAVFs in the anterior cranial fossa is preferred over the endovascular approach. Due to the proximity of some dAVFs to the orbit, endovascular embolization of the dAVF carries a higher risk of complications, primarily due to the formation of dangerous extracranial or intracranial anastomoses. We present the case of a 64-year-old male with an incidentally discovered Borden type III dAVF arising from the anterior branches of the middle meningeal artery and draining into the middle cerebral vein. Due to the location of his dAVF, craniotomy was selected for ligation of the fistula. The procedure went without complication. A catheter angiogram of the brain one month after surgery showed an absence of flow through the arteriovenous fistula and a middle meningeal artery that had returned to its normal caliber.

A Proposed Grading Scale for Predicting Outcomes After Stereotactic Radiosurgery for Dural Arteriovenous Fistulas

BACKGROUND

There are presently no grading scales that specifically address the outcomes of cranial dural arteriovenous fistula (dAVF) after stereotactic radiosurgery (SRS).

OBJECTIVE

To design a practical grading system that would predict outcomes after SRS for cranial dAVFs.

METHODS

From the International Radiosurgery Research Foundation (University of Pittsburgh [41 patients], University of Pennsylvania [6 patients], University of Sherbrooke [2 patients], University of Manitoba [1 patient], West Virginia University [2 patients], University of Puerto Rico [1 patient], Beaumont Health System 1 [patient], Na Homolce Hospital [13 patients], the University of Virginia [48 patients], and Yale University [6 patients]) centers, 120 patients with dAVF treated with SRS were included in the study. The factors predicting favorable outcome (obliteration without post-SRS hemorrhage) after SRS were assessed using logistic regression analysis. These factors were pooled with the factors that were found to be predictive of obliteration from 7 studies with 736 patients after a systematic review of literature. These were entered into stepwise multiple regression and the best-fit model was identified.

RESULTS

Based on the predictive model, 3 factors emerged to develop an SRS scoring system: cortical venous reflux (CVR), prior intracerebral hemorrhage (ICH), and noncavernous sinus location. Class I (score of 0-1 points) predicted the best favorable outcome of 80%. Class II patients (2 points score) had an intermediate favorable outcome of 57%, and class III (score 3 points) had the least favorable outcome at 37%. The ROC analysis showed better predictability to prevailing grading systems (AUC = 0.69; P = .04). Kaplan-Meier analysis showed statistically significant difference between the 3 subclasses of the proposed grading system for post-SRS dAVF obliteration (P = .001).

CONCLUSION

The proposed dAVF grading system incorporates angiographic, anatomic, and clinical parameters and improves the prediction of the outcomes following SRS for dAVF as compared to the existing scoring systems.

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.

Suboccipital, Supracerebellar, Infratentorial Approach for Microsurgical Clipping of a Ruptured Tentorial, Straight Sinus Type Dural Arteriovenous Fistula

BACKGROUND

Dural arteriovenous fistulas (dAVFs) can often be successfully treated with endovascular embolization; however, surgery is occasionally still required.

CASE DESCRIPTION

Herein, we discuss a 65-year-old male patient who presented with a Hunt-Hess IV subarachnoid hemorrhage, intraventricular hemorrhage, and cerebellar intracranial hemorrhage secondary to a ruptured Borden type III tentorial (straight sinus) dAVF. Angiography revealed supply from the left occipital and posterior meningeal arteries and direct drainage into the cerebellar cortical veins with venous aneurysms in both cerebellar hemispheres. Both transarterial and transvenous embolization were attempted, without success. Therefore, the patient was taken to the operating room for clip ligation of the dAVF. The operative video demonstrates a bilateral suboccipital craniotomy and supracerebellar infratentorial approach for surgical clipping of the dAVF.

CONCLUSIONS

The case and operative video provide a valuable addition to surgical literature in an era where surgical management of dAVFs has become relatively rare.

Venous outflow restriction as a predictor of cavernous sinus dural arteriovenous fistula obliteration after Gamma Knife surgery

OBJECTIVE

Gamma Knife surgery (GKS) obliterates 65%-87% of cavernous sinus dural arteriovenous fistulas (CSDAVFs). However, the hemodynamic effect on GKS outcomes is relatively unknown. The authors thus used the classification scheme developed by Suh et al. to explore this effect.

METHODS

The authors retrospectively (1993-2016) included 123 patients with CSDAVFs who received GKS alone at the institute and classified them as proliferative type (PT; n = 23), restrictive type (RT; n = 61), or late restrictive type (LRT; n = 39) after analyzing their pre-GKS angiography images. Treatment parameters, the presence of numerous arterial feeders, and venous drainage numbers were compared across the CSDAVF types. Patients' follow-up MR images were evaluated for the presence of complete obliteration. A Kaplan-Meier analysis was conducted to determine the correlation between CSDAVF types and outcomes.

RESULTS

The 36-month probability of complete obliteration was 74.3% for all patients, with no significant differences across types (p = 0.56). PT had the largest radiation volume (6.5 cm3, p < 0.001), the most isocenters (5, p = 0.015) and venous drainage routes (3, p < 0.001), and the lowest peripheral dose (16.6 Gy, p = 0.011) and isodose level coverage (64.3%, p = 0.006). CSDAVFs presenting with ocular patterns were less likely to be completely obliterated (hazard ratio 0.531, p = 0.009). After adjustment for age, CSDAVFs with more venous drainage routes were less likely to be completely obliterated (hazard ratio 0.784, p = 0.039).

CONCLUSIONS

GKS is an equally effective treatment option for all 3 CSDAVF types. Furthermore, the number of venous drainage routes may help in predicting treatment outcomes and making therapeutic decisions.

Updates in the management of cranial dural arteriovenous fistula

Dural arteriovenous fistula (dAVF) accounts for approximately 10% of all intracranial vascular malformations. While they can be benign lesions, the presence of retrograde venous drainage and cortical venous reflux makes the natural course of these lesions aggressive high risk of haemorrhage, neurological injury and mortality. Endovascular treatment is often the first line of treatment for dAVF. Both transarterial and transvenous approaches are used to cure dAVF. The selection of treatment approach depends on the angioarchitecture of the dAVF, the location, the direction of venous flow. Surgery and, to a lesser extent, stereotactic radiosurgery are used when endovascular approaches are impossible or unsuccessful.

Stereotactic Radiosurgery for Dural Arteriovenous Fistulas Involving the Transverse-Sigmoid Sinus : A Single Center Experience and Review of the Literatures

Objective

We retrospectively assessed the efficacy of stereotactic radiosurgery (SRS) for dural arteriovenous fistulas (DAVFs) involving the transverse-sigmoid sinus and analyzed the angiographic and clinical results with our 8-year experience.

Methods

Nine patients with intracranial DAVFs involving the transverse-sigmoid sinus underwent SRS using a Gamma Knife^® (Elekta Inc., Atlanta, GA, USA) between 2009 and 2016. Five patients underwent SRS for residual DAVFs after embolization and four patients were treated with SRS alone. The median target volume was 1.9 cm³ (range, 0.8–14.2) and the median radiation dose of the target was 17 Gy (range, 16–20). The median follow-up period was 37 months (range, 7–81).

Results

Pulsating tinnitus (33%) was the most common symptom. DAVFs were completely obliterated in four patients (44%) and subtotally obliterated in five (56%). Six patients (67%) showed complete recovery of symptoms or signs, and three (33%) showed incomplete recovery. One patient experienced a recurrent seizure. Adverse radiation effects after SRS occurred in one patient (11%). The total obliteration rates after SRS were 16.7%, 37.5%, and 68.7% at 1, 2, and 3 years, respectively. The median interval from SRS to total obliteration of the fistula was 31 months (range, 12–38). The rates at which the symptoms started to improve were 40% at 1 month and 80% at 2 months after SRS. Symptoms started to improve at a median of 5 weeks after SRS (range, 3–21).

Conclusion

SRS with or without embolization is a safe and effective treatment to relieve symptoms and obliterate DAVFs on the transverse-sigmoid sinus.

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.

Treatment of cranial dural arteriovenous fistulas with exclusive cortical venous drainage: A single-center cohort of 35 patients

Background and purpose Dural arteriovenous fistulas (DAVFs) with cortical venous drainage often present with hemorrhage or neurological deficits and prompt treatment is indicated. Disconnection of the draining vein is considered curative. We present the multimodality treatment results of 35 patients with cranial DAVFs with exclusive cortical venous drainage. Materials and methods Between January 2010 and January 2017, 35 consecutive patients with cranial dural fistulas with exclusive cortical venous drainage were treated. There were 27 men and eight women, mean age 68 years (range 45-87). Clinical presentation was hemorrhage in 23 (66%), pulsatile bruit in two (6%), seizures in one (3%) and blurred vision in one (3%). In eight patients (22%), the DAVF was an incidental finding. Location of the DAVFs was convexity in 25 (71%), posterior fossa in eight (23%) and tentorium in two (6%). Results Surgery was performed in four patients with anterior cranial fossa fistulas and in one patient with a tentorial dural fistula. In 30 patients, embolization with Onyx via the arterial route was the primary treatment with complete obliteration in one session in 25 patients. Additional surgical or endovascular sessions were necessary in five patients after incomplete embolization and in one patient after incomplete surgery. Obliteration was confirmed with angiography after three months. There were no procedural complications. Conclusions Patients with dural fistulas with cortical venous drainage were cured with a strategy of arterial endovascular treatment with Onyx and surgery. These techniques were either primarily successful or complementary. There were no complications of treatment.

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.

Stereotactic radiosurgery for intracranial dural arteriovenous fistulas: its clinical and angiographic perspectives

BACKGROUND

To assess the efficacy of stereotactic radiosurgery (SRS) for intracranial dural arteriovenous fistulas (DAVFs), the authors retrospectively reviewed our 7-year experience. We evaluated the obliteration rate, improvement in clinical symptoms, and complications.

METHODS

Thirty patients with DAVF underwent SRS using a Gamma Knife between 2009 and 2015. Twenty-three patients were treated with SRS alone, and seven patients underwent SRS for residual or recurrent DAVFs after embolization or surgery. Chemosis, diplopia, and pulsating tinnitus were the most common symptoms. Median target volume was 2.9 cm³ (range, 0.8-13.6 cm³), and median radiation dose to the target was 17 Gy (range, 12-20 Gy). Median follow-up period was 33 months (range, 6-82 months).

RESULTS

At the last neuroimaging follow-up, DAVFs were totally obliterated in 23 patients (77%) and subtotally in 7 (23%). At the last clinical follow-up, 21 patients (70%) showed complete recovery, and 9 (30%) showed incomplete recovery in symptoms or signs. None experienced worsening symptoms or signs. Asymptomatic perilesional edema after SRS occurred in one patient (3%). Total obliteration rates after SRS were 43% at 1 year, 79% at 2 years, and 95% at 5 years. Improvement rates of neurological function after SRS were 12% at 1 month, 52% at 2 months, 72% at 3 months, and 96% at 6 months. A multivariate analysis revealed that Borden type 1 (p = 0.019, hazard ratio, 3.254, 95% confidence interval, 1.216-8.707) was significantly associated with symptom improvement.

CONCLUSIONS

SRS for intracranial DAVFs provided a high obliteration rate and a relatively low risk of radiation-induced complications. In selected benign cases without cortical venous drainage, SRS is a safe and effective treatment for symptom relief and fistula obliteration, even though the time course of improvement is longer than those of embolization and surgery.

Stereotactic Radiosurgery for Dural Carotid Cavernous Sinus Fistulas

OBJECTIVE

We reviewed our 7-year experience to assess the efficacy of stereotactic radiosurgery (SRS) for dural carotid cavernous fistulas (DCCFs). We analyzed the clinical outcome, complications, and angiographic results.

METHODS

We performed a retrospective analysis of 18 consecutive patients with DCCFs treated by SRS alone using Gamma Knife between 2009 and 2015. Median target volume was 2.6 cm³ (range, 0.6-11.6 cm³), and median radiation dose to the target was 17 Gy (range, 14-19 Gy). Median follow-up period was 30 months (range, 6-65 months).

RESULTS

Fifteen patients (83%) achieved total obliteration of the DCCF, and a subtotal obliteration of the DCCF was achieved in 3 patients (17%). Total obliteration rates after SRS were 53% at 1 year and 90% at 2 years. Twelve patients (67%) showed complete recovery from symptoms or signs, and 6 patients (33%) showed incomplete recovery. Improvement rates of neurologic function after SRS were 56% at 1 month, 72% at 3 months, and 94% at 6 months. None of the patients experienced radiation-related complications. A univariate analysis revealed that absence of hypertension (P = 0.025), seizure (P = 0.025), and cortical venous drainage (P = 0.013) were significantly associated with symptoms improvement.

CONCLUSIONS

SRS for DCCFs offered a high obliteration rate with low risk of radiation-induced complications. In patients with benign DCCFs that are not amenable to embolization or microsurgery, SRS is a safe and effective treatment for complete obliteration of the arteriovenous shunt and for improving quality of life.

Quantifying the Cerebral Hemodynamics of Dural Arteriovenous Fistula in Transverse Sigmoid Sinus Complicated by Sinus Stenosis: A Retrospective Cohort Study

BACKGROUND AND PURPOSE

Sinus stenosis occasionally occurs in dural arteriovenous fistulas. Sinus stenosis impedes venous outflow and aggravates intracranial hypertension by reversing cortical venous drainage. This study aimed to analyze the likelihood of sinus stenosis and its impact on cerebral hemodynamics of various types of dural arteriovenous fistulas.

MATERIALS AND METHODS

Forty-three cases of dural arteriovenous fistula in the transverse-sigmoid sinus were reviewed and divided into 3 groups: Cognard type I, type IIa, and types with cortical venous drainage. Sinus stenosis and the double peak sign (occurrence of 2 peaks in the time-density curve of the ipsilateral drainage of the internal jugular vein) in dural arteriovenous fistula were evaluated. "TTP" was defined as the time at which a selected angiographic point reached maximum concentration. TTP of the vein of Labbé, TTP of the ipsilateral normal transverse sinus, trans-fistula time, and trans-stenotic time were compared across the 3 groups.

RESULTS

Thirty-six percent of type I, 100% of type IIa, and 84% of types with cortical venous drainage had sinus stenosis. All sinus stenosis cases demonstrated loss of the double peak sign that occurs in dural arteriovenous fistula. Trans-fistula time (2.09 seconds) and trans-stenotic time (0.67 seconds) in types with cortical venous drainage were the most prolonged, followed by those in type IIa and type I. TTP of the vein of Labbé was significantly shorter in types with cortical venous drainage. Six patients with types with cortical venous drainage underwent venoplasty and stent placement, and 4 were downgraded to type IIa.

CONCLUSIONS

Sinus stenosis indicated dysfunction of venous drainage and is more often encountered in dural arteriovenous fistula with more aggressive types. Venoplasty ameliorates cortical venous drainage in dural arteriovenous fistulas and serves as a bridge treatment to stereotactic radiosurgery in most cases.

Novel approaches to access and treatment of cavernous sinus dural arteriovenous fistula (CS-DAVF): case series and review of the literature

Caroticocavernous fistula or cavernous sinus dural arteriovenous fistula (CS-DAVF) has presented various treatment challenges over many years. This paper outlines these challenges in a review of the literature, and attempts to address them by analyzing the anatomical and hemodynamic characteristics of 32 consecutive patients with CS-DAVF treated between 2007 and 2016, in doing so proposing novel strategies for safe access and treatment of CS-DAVF.

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.

Stereotactic radiosurgery for intracranial dural arteriovenous fistulas: a systematic review

OBJECT

The goal of this study was to evaluate the obliteration rate of intracranial dural arteriovenous fistulas (DAVFs) in patients treated with stereotactic radiosurgery (SRS), and to compare obliteration rates between cavernous sinus (CS) and noncavernous sinus (NCS) DAVFs, and between DAVFs with and without cortical venous drainage (CVD).

METHODS

A systematic literature review was performed using PubMed. The CS DAVFs and the NCS DAVFs were categorized using the Barrow and Borden classification systems, respectively. The DAVFs were also categorized by location and by the presence of CVD. Statistical analyses of pooled data were conducted to assess complete obliteration rates in CS and NCS DAVFs, and in DAVFs with and without CVD.

RESULTS

Nineteen studies were included, comprising 729 patients harboring 743 DAVFs treated with SRS. The mean obliteration rate was 63% (95% CI 52.4%–73.6%). Complete obliteration for CS and NCS DAVFs was achieved in 73% and 58% of patients, respectively. No significant difference in obliteration rates between CS and NCS DAVFs was found (OR 1.72, 95% CI 0.66–4.46; p = 0.27). Complete obliteration in DAVFs with and without CVD was observed in 56% and 75% of patients, respectively. A significantly higher obliteration rate was observed in DAVFs without CVD compared with DAVFs with CVD (OR 2.37, 95% CI 1.07–5.28; p = 0.03).

CONCLUSIONS

Treatment with SRS offers favorable rates of DAVF obliteration with low complication rates. Patients harboring DAVFs that are refractory or not amenable to endovascular or surgical therapy may be safely and effectively treated using SRS.

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.

The usefulness of subcutaneous infiltration of epinephrine-containing lidocaine for curative transarterial embolization of dural arteriovenous fistula. A technical note

Recently, transarterial embolization (TAE) with liquid embolic materials has been recognized as one of the curative therapeutic options for non-sinus type dural arteriovenous fistula (d-AVF). To prevent glue fragmentation and incomplete obliteration, flow reduction of transosseous high-flow feeders is one of the key points of this therapy. However, flow reduction of transosseous feeders is sometimes difficult with previously reported techniques such as particle embolization, manual compression, or proximal balloon occlusion. This report introduces a new technique to reduce the flow of transosseous feeders using epinephrine-containing lidocaine, and describes a case of intracranial d-AVF successfully treated with this technique. The usefulness and efficacy of the technique are discussed.

A treatment option for nontraumatic adult-type dural arteriovenous fistulas: transarterial venous coil embolization

OBJECTIVE

Transvenous coil embolization of the affected venous outlet is the most effective treatment method for the management of nontraumatic adult dural arteriovenous fistulas (DAVFs). However, such an approach is not always feasible. We discuss nontraumatic adult DAVFs that were treated with transarterial coil embolization of the proximal venous outlet at our facility, as well as cases previously reported in the literature.

METHODS

This study included 8 patients who had undergone transarterial coil embolization of the proximal venous outlet for the treatment of nontraumatic adult DAVFs (4 cases in our series and 4 cases in the literature). All clinical, angiographic, and procedural data were retrospectively collected from medical charts or the literature and recorded on standardized forms by a physician. The DAVFs were classified according to the venous drainage pattern.

RESULTS

In all 8 patients, occlusion of the proximal venous site of the fistula was possible by using coils through the arterial feeders; this resulted in complete recovery in all patients. The access route for 7 of the 8 cases was the middle meningeal artery, and in 1 case was the meningohypophyseal artery. In all 8 patients the access artery was relatively smooth, with distal enlargement in the fistula region.

CONCLUSIONS

If a distally enlarged feeding artery is observed among the multiple feeding arteries, it suggests the existence of a large fistula and may serve as an access route for transarterial venous coil embolization. This procedure may offer a more effective and safer treatment than other endovascular approaches.

Transarterial treatment with Onyx of Cognard type IV anterior cranial fossa dural arteriovenous fistulas

BACKGROUND AND PURPOSE

Cognard type IV anterior cranial fossa dural arteriovenous fistulas (DAVFs) are rare lesions with a high risk of intracranial hemorrhage. We present our experience with the use of Onyx via the arterial route in these aggressive lesions.

MATERIALS AND METHODS

Between October 2009 and October 2011, six consecutive patients diagnosed with Cognard type IV anterior cranial fossa DAVFs were treated transarterially with Onyx in our department. All patients were male; mean age was 55 years (range 38-68). Four patients presented with intracranial hemorrhage as the initial manifestation; one patient presented with seizures at the time of diagnosis and experienced intracranial hemorrhage during the antiepileptic therapy; and the other patient was asymptomatic.

RESULTS

In five patients, complete obliteration was achieved with transarterial Onyx injection in a single treatment session; in the remaining patient, subtotal occlusion was achieved and gamma knife treatment was followed. The average time of injection was 19 min (range 5-28) for every pedicle catheterized and the average amount of Onyx was 3.2 ml (range 0.4-6.3) for each lesion. All patients recovered uneventfully after embolization. No mortality or permanent morbidity was observed in this series. Follow-up digital subtraction or MR angiography confirmed durable obliteration of the fistulas in five cured cases. No patients suffered intracranial hemorrhage during the follow-up period.

CONCLUSIONS

In this small series, our experience with the use of Onyx for arterial embolization of Cognard type IV DAVFs is encouraging, with durable complete cure in most lesions without severe complications.

Surgical management of dural arteriovenous fistulas of the transverse-sigmoid sinus in 42 patients

A retrospective study was performed to analyse a prospectively collected database from a single surgeon (M.K.M.) of transverse-sigmoid sinus dural arteriovenous fistulas (DAVF) between 1991 and August 2011. During the study period, 144 patients with 160 DAVF were managed. Sixty-five of the DAVF were located in the transverse-sigmoid sinus and 42 were treated with surgery, or embolisation and surgery. All patients who underwent surgery were symptomatic with retrograde cortical venous drainage. The average follow-up period was 18months (range, 2-82months). Total elimination of the DAVF was achieved in all instances, including two patients (5%) who required further surgery after postoperative cerebral angiography showed that some venous drainage had persisted after the first operation. There was no new permanent neurological deficit or mortality attributable to surgery. Our institutional experience shows that in selected patients with transverse-sigmoid sinus DAVF, the involved sinus can be surgically resected with a high success rate and it is as safe as many alternative options. We suggest that this definitive treatment option should be offered to patients, and the outcome should be compared to other treatment modalities.

Characteristics and long-term outcome of 251 patients with dural arteriovenous fistulas in a defined population

OBJECT

Management of dural arteriovenous fistulas (DAVFs) has changed during the last decades due to increased knowledge of their pathophysiology and natural history as well as advances in treatment modalities. The authors describe the characteristics and long-term outcome of a large consecutive series of patients with DAVFs.

METHODS

Altogether 251 patients with 261 DAVFs were treated in 2 of the 5 neurosurgery departments at Helsinki and Kuopio University Hospitals between 1944 and 2006. Clinical data and radiological examinations were reviewed to assess patients' overall long-term clinical outcome.

RESULTS

The detection rate of DAVFs increased markedly in the 1970s and again in the 1990s when digital subtraction angiography was introduced. The incidence of DAVFs in a defined southern Finnish population was 0.51 per 100,000 individuals per year, which represents 32% of all the brain arteriovenous malformations. In the early part of the series, DAVFs were treated by proximal ligation of the feeding arteries. Later, most of the patients underwent preoperative embolization and subsequent craniotomy, and since 2000 stereotactic radiosurgery has been increasingly used in the treatment of DAVFs. Fifty-nine percent of the 261 fistulas were totally occluded. Treatment-related major complications were seen in 21 patients.

CONCLUSIONS

The advances in diagnostic methods (digital subtraction angiography, CT, and MRI) increased the detection rate of DAVFs, and as treatment modalities developed, the results of treatment and outcome of patients markedly improved with the introduction of endovascular techniques and stereotactic radiosurgery. Microsurgery is of limited use in DAVFs resistant to other treatment modalities.

Transarterial embolization of dural arteriovenous fistulas of the anterior cranial fossa with Onyx

Dural arteriovenous fistulas (DAVF) of the anterior cranial fossa are often associated with hemorrhage and are usually treated surgically. This clinical study summarizes our preliminary experience in the transarterial embolization of these lesions. We retrospectively reviewed the data for 11 patients with anterior cranial fossa DAVF who underwent transarterial embolization with the Onyx Liquid Embolic System (eV3 Endovascular, Plymouth, MN, USA) at our institute between 2007 and 2011. In four patients, a balloon-assisted technique was used to facilitate superselective catheterization. According to the Cognard classification of DAVF, three fistulas were type III, and the other eight were type IV. DAVF were completely obliterated in 10 patients after treatment via a single ethmoidal artery, but the other patient was not completely cured. No signs of rebleeding or symptom progression were observed at a mean follow-up of 18.5 months (range: 2-49 months). Transarterial embolization using Onyx is therefore feasible and effective for the management of DAVF of the anterior cranial fossa.

Stereotactic radiosurgery for cerebral dural arteriovenous fistulas

Object

Given the feasibility of curative surgical and endovascular therapy for cerebral dural arteriovenous fistulas (DAVFs), there is a relative paucity of radiosurgical series for these lesions as compared with their arteriovenous malformation counterparts.

Methods

The authors reviewed records of 56 patients with 70 cerebral DAVFs treated at their institution over the past 6 years. Ten DAVFs (14%) in 9 patients were treated with stereotactic radiosurgery (SRS), with follow-up obtained for 8 patients with 9 DAVFs. They combined their results with those obtained from a comprehensive review of the literature, focusing on obliteration rates, post-SRS hemorrhage rates, and other complications.

Results

In the authors' group of 9 DAVFs, angiographic obliteration was seen in 8 cases (89%), and no post-SRS hemorrhage or complications were observed after a mean follow-up of 2.9 years. Combining the results in these cases with data obtained from their review of the literature, they found 558 DAVFs treated with SRS across 14 series. The overall obliteration rate was 71%; transient worsening occurred in 9.1% of patients, permanent worsening in 2.4% (including 1 death, 0.2% of cases), and post-SRS hemorrhage occurred in 1.6% of cases (4.8% of those with cortical venous drainage [CVD]). The obliteration rate for cavernous DAVFs was 84%, whereas the rates for transversesigmoid and for tentorial DAVFs were 58% and 59%, respectively (adjusted p values, pcav,TS = 1.98 × 10−4, pcav,tent = 0.032). Obliteration rates were greater for DAVFs without CVD (80%, compared with 60% for those with CVD, p = 7.59 × 10−4). Both transient worsening and permanent worsening were less common in patients without CVD than in those with CVD (3.4% vs 7.3% for transient worsening and 0.9% vs 2.4% for permanent worsening).

Conclusions

Stereotactic radiosurgery with or without adjunctive embolization is an effective therapy for DAVFs that are not amenable to surgical or endovascular monotherapy. It is best suited for lesions without CVD and for cavernous DAVFs.

Onyx 18 embolisation of dural arteriovenous fistula via arterial and venous pathways: preliminary experience and evaluation of the short-term outcomes

OBJECTIVE

This paper mainly focuses on our preliminary experience and short-term outcome evaluation of embolisation of non-cavernous dural arteriovenous fistulas (ncsDAVFs) and cavernous sinus dural arteriovenous fistulas (csDAVFs) using Onyx 18 (ev3, Plymouth, MN), and in combination with coils, via arterial and venous approaches, respectively.

METHODS

Between August 2008 and March 2010, 21 DAVFs (11 ncsDAVFs and 10 csDAVFs; age range: 28-68 years; 12 females and 9 males) were undertaken. Borden classification showed Type III in 1 and Type II in 10 ncsDAVFs, and Type II in 4 and Type I in 6 csDAVFs. Onyx 18 was used in 11 ncsDAVFs (10 via single feeder and 1 via 2 feeders). Onyx 18 or in combination with coils was used in 10 csDAVFs (9 via the inferior petrosal sinus and 1 via the superior ophthalmic vein).

RESULTS

Total occlusion in immediate angiography was achieved in 18 cases (85.7%; 10 ncsDAVFs and 8 csDAVFs), and near-total occlusion in 1 ncsDAVF and 2 csDAVFs. Onyx 18 was migrated into normal vasculature in two ncsDAVFs without any sequelae. One csDAVF had VI cranial nerve palsy post-operatively, which completely recovered 2 weeks post-embolisation. Follow-up angiography at 3-12 months showed complete occlusion in 20 cases (95.2%; 10 ncsDAVFs and 10 csDAVFs). One ncsDAVF (4.8%) recurred after 3 months and was successfully re-embolised.

CONCLUSION

Preliminary results achieved after embolising 11 ncsDAVFs and 10 csDAVFs using Onyx 18 and in combination with coils via arterial and venous pathways, respectively, appeared to be safe, feasible and effective, as 95.2% of cases were totally occluded without any clinical sequelae.

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

BACKGROUND AND PURPOSE

Recently some series have been published about the use of Onyx for the treatment of DAFVs with satisfactory results. Our aim was to describe the treatment of different types of intracranial DAVFs with transcatheter injection of Onyx through an arterial approach.

MATERIALS AND METHODS

At the Department of Interventional Neuroradiology, Hospital Lariboisière Paris, between January 2005 and January 2010, we treated 44 DAVFs in 42 patients. All patients were initially treated by arterial injection of Onyx. The average patient age was 56 years (range, 27-86 years), and there were 17 women and 25 men treated.

RESULTS

A total of 58 arterial pedicles were catheterized, with the middle meningeal artery representing the most common site (n = 38). The average time of injection was 30 minutes (range, 15-60 minutes), and the average amount of Onyx was 2.5 mL (range, 0.6-6.5 mL). Of the 20 fistulas with direct venous drainage into a dural sinus (types I and II), we achieved the preservation of the sinus in 7 patients. Of the 44 fistulas embolized, 8 required a second embolization treatment and 1 fistula required a third treatment. In 9 cases, a complementary treatment was performed via transvenous embolization with coils and/or open surgery. Early complications were observed in 6 patients: Four had nerve injury (facial palsy, n = 2, and neuralgia, n = 2), and 2 had complications related to extension of venous thrombosis postembolization. All 6 patients had partial or complete resolution of these symptoms.

CONCLUSIONS

The treatment of DAVFs by intracranial arterial injection of Onyx is safe, and, in most cases, results in the occlusion of the arterial venous shunt. In DAVFs with direct sinus drainage, sinus preservation was only possible in 7 of 20 patients (35%).

The Natural History of Cranial Dural Arteriovenous Fistulae With Cortical Venous Reflux—The Significance of Venous Ectasia

BACKGROUND:

The quoted risk of hemorrhage from dural arteriovenous fistulae with cortical venous reflux varies widely, and the influence of angiographic grade on clinical course has not previously been reported.

OBJECTIVE:

To assess the risk of hemorrhage and the influence of angiographic grade on this risk, compared with known predictors of hemorrhage such as presentation.

METHODS:

Seventy-five fistulae with cortical venous reflux identified in our arteriovenous malformations clinic between 1992 and 2007 were followed up clinically, and their angiograms were reviewed.

RESULTS:

There were 8 hemorrhages in 90 years of follow-up. The annual incidence of hemorrhage before any treatment was 13%, and 4.7% after partial treatment, giving an overall incidence of 8.9% before definitive treatment. Borden and Cognard grades were poor discriminators of risk for lesions with the exception of Cognard type IV lesions. These lesions, characterized by venous ectasia, had a 7-fold increase in the incidence of hemorrhage (3.5% no ectasia vs 27% with ectasia). Patients presenting with hemorrhage (20%) or nonhemorrhagic neurological deficit (22%) had a higher incidence of hemorrhage than those with a benign presentation (4.3%), but this may be directly linked to the presence of venous ectasia.

CONCLUSION:

In this series untreated dural arteriovenous fistulae with cortical venous reflux had a 13% annual incidence of hemorrhage after diagnosis. There was a significant difference between those with and without venous ectasia. This should be confirmed by further studies, but probably defines a high-risk subgroup of patients that requires rapid intervention.

Management, risk factors and outcome of cranial dural arteriovenous fistulae: a single-center experience

BACKGROUND

The role of endovascular interventions in managing dural arteriovenous fistulas (DAVFs) is increasing. Furthermore, in patients with aggressive DAVFs, different surgical interventions are required for complete obliteration or disconnection. Our objective was to evaluate the management of patients with intracranial DAVFs treated in our institution to identify the parameters that may help guide the long-term management of these lesions.

METHODS

The hospital records of 53 patients with intracranial DAVFs were reviewed. We then conducted a systematic telephone interview to obtain long-term follow-up information.

RESULTS

The main presenting symptoms were tinnitus and headache. Nineteen (35%) patients presented with intracranial bleeding, 84% of patients scored between 0 and 2 using a modified Rankin Scale at the last follow-up visit. Twenty-four patients were treated surgically. Overall postoperative complications occurred in seven (29%) surgically treated patients, but only two patients permanently worsened. For patients with Borden type II and III fistulas, the annual incidence of hemorrhage was 30%. Two patients had late recurrences of surgically and endovascularly occluded DAVFs. Long-term follow-up showed that compared with spinal DAVFs, only 50% of intracranial DAVFs showed complete remission of symptoms, 41% partial remission, 6% no remission and 4% deterioration of symptoms that led to treatment of the DAVF.

CONCLUSION

In general, intracranial DAVFs can be successfully surgically managed by simple venous disconnection in many cases. However, half of the patients do not show complete remission of symptoms. Age and the occurrence of perioperative complication were the most important determinants of outcome.

Long-term outcome in patients treated for benign dural arteriovenous fistulas of the posterior fossa

INTRODUCTION

Dural arteriovenous fistula (dAVF) draining into a dural sinus without recruitment of cortical veins is regarded as relatively benign lesion and treatment is advocated only if the patient is severely affected by the symptoms. The aim of this study was to compare the clinical outcomes in patients who received endovascular treatment or no treatment, respectively.

METHODS

Twenty-one patients presented consecutively with pulsating tinnitus as leading symptom and with angiographically proven dAVF at the transverse or sigmoid sinus (Borden I). Nine patients underwent different types of endovascular embolisation, and 12 patients were not treated. After a median follow-up period of 2.3 years, outcome was evaluated by assessing the patients' symptoms and scores on the mRS, EQ-5D, SF-36 and HIT-6 scales.

RESULTS

Complete long-term closure of the dAFV was achieved in two out of nine cases; subtotal occlusion was found in seven patients. Pulsating tinnitus persisted less frequently in treated than in untreated patients. Neurologic symptoms occurred in both groups. Neither these findings nor the clinical outcome and scores on the quality-of-life scales varied substantially between the two groups.

CONCLUSION

Partial treatment did not resolve the clinical symptoms of patients with "benign" dural AVF in the follow-up and was not clearly superior to conservative management. These results suggest that embolisation should be offered only if there is a possibility of a complete cure without major periinterventional risks. Further studies should be performed to assess the risk-benefit ratio of pursuing more aggressive treatment strategies in patients with unbearable symptoms.

Curative embolization with Onyx of dural arteriovenous fistulas with cortical venous drainage

BACKGROUND AND PURPOSE

Dural fistulas with cortical venous drainage often present with hemorrhage or neurologic deficit, and prompt treatment is indicated. Occlusion of the draining vein by endovascular techniques or surgical disconnection is considered curative. We present our first endovascular experience with use of Onyx via the arterial route in these aggressive fistulas.

MATERIALS AND METHODS

Between October 2008 and October 2009, 8 consecutive patients with a dural fistula with exclusive cortical venous drainage were treated with Onyx. Three patients presented with hemorrhage; 3, with hemianopsia; 1 with bruit; and 1 after incomplete coil occlusion of a benign sigmoid sinus dural fistula. Fistula location was the sigmoid sinus segment in 4, the occipital area in 2, the cavernous sinus in 1, and the torcula in 1.

RESULTS

In all 8 patients, it was possible to occlude the proximal venous site of the fistula with Onyx via arterial feeders, resulting in complete cure in all. In 6 patients, a prolonged (17- to 29-minute) single middle meningeal artery injection was sufficient to occlude the venous site of the fistula with retrograde occlusion of other arterial feeders; in the other 2 patients, 2 injections in supplying arteries were needed. Follow-up angiograms after 6-12 weeks confirmed lasting complete occlusion of the fistulas. All patients were clinically cured, there were no complications.

CONCLUSIONS

In this small series, curative embolization of dural fistulas with exclusive cortical venous drainage by using Onyx via the arterial route was possible in all patients.