The limitations and risks of transarterial Onyx injections in the treatment of grade I and II DAVFs

Background and objective

Embolization of grade III–V intracranial DAVFs using Onyx is feasible with promising results, indicating stability at the time of mid-term follow-up. This article is to evaluate the role of transarterial Onyx embolization in the treatment of grade I and II intracranial dural arteriovenous fistulas (DAVFs), including its limitations and risks.

Methods

We retrospectively studied consecutive 26 patients (8 women and 18 men) treated for an grade I and II intracranial DAVF since 2006 in whom a transarterial approach was attempted with Onyx-18 embolization. There were 18 transverse-sigmoid sinus, 4 cavernous sinus, 2 superior sagittal sinus, 1 inferior petrosal sinus and 1 intradiploic fistulas. Five fistulas were Type I, 8 were Type IIa, and 13 were Type IIa + b, according to the Cognard classification. The mean clinical follow-up period was 15.6 months.

Results

Anatomic cure was proven in 13 patients (50%) and clinical cure was obtained in 17 cases (65.4%). These 13 cures were achieved after a single procedure. All these 13 patients underwent a follow-up angiography, which has confirmed the complete cure. Partial occlusion was obtained in 13 patients. Complications were as follows: 2 cardiac Onyx migration, 2 reflexive bradyarrythmia, 1 transient visual hallucination, 2 transient fifth nerve palsies and 1 permanent seventh nerve palsy in inferior petrosal sinus DAVF.

Conclusions

Based on this experience, grade I and II intracranial DAVFs may be treated with transarterial Onyx embolization to reduce the shunted blood flow and to facilitate subsequent transvenous embolization or surgery.     

Percutaneous transvenous packing of cavernous sinus with Onyx for cavernous dural arteriovenous fistula

Objective

The aim of this study is to describe the technique and results of the transvenous approach for occlusion of cavernous dural arteriovenous fistulas (DAVFs) with Onyx.

Methods

Eleven patients presenting with clinically symptomatic DAVFs, were treated between August 2005 and February 2007 at Beijing Tiantan Hospital. We were able to navigate small hydrophilic catheters and microguidwires through the facial vein or inferior petrosal sinus (IPS) into the ipsilateral cavernous sinus. After reaching the fistula site the cavernous sinus was packed with Onyx or combining with detachable platinum coils.

Results

We were able to reach the fistula site and to achieve a good packing of Onyx or combining with coils within the arteriovenous shunting zone in 10 patients. The final angiogram showed complete occlusion of the arteriovenous fistula. Two (18.2%) patients developed a bradycardia during DMSO injection. No complications related to the approach were observed.

Conclusions

Transvenous occlusion of cavernous DAVFs is a feasible approach, even via facial vein or via IPS. Onyx may be another option for cavernous packing other than detachable platinum coils.     

Embolization of intracranial dural arteriovenous fistulas with Onyx-18

Background and purpose

The use of Onyx in the treatment of AVMs has been reported in the literature, but experience in the treatment of DAVF is lacking. We report the clinical outcome obtained in the treatment of dural arteriovenous fistulas (DAVFs) using a new liquid embolic agent, Onyx-18.

Methods

The present series included 21 patients; 9 had DAVFs draining directly into the cortical veins, 6 had DAVFs draining directly into the dural sinus, 4 had DAVFs draining through the ophthalmic veins and 2 had DAVFs involving the dural sinus with leptomeningeal retrograde venous drainage Clinical data were extracted from hospital files and all patients were followed.

Results

In 14 patients (70%) there was complete angiographic elimination of the shunts and resolution of the symptoms. The remaining 7(30%) patients was not cured with residual shunts. Adverse events occurred in 6(30%) of 21 patients with 1 DAVF located at the transverse sigmoid sinus, 2 at tentorium, and 3 at the cavernous sinus. Cranial deficits occurred in 3(15%) patients, brain infarction in 1(5%) patient and microcatheter gluing in 1(3.2%) patient. At final follow up, 20 patients were asymptomatic with 1 showed clinical improvement.

Conclusion

Definitive cure may be attained effectively with Onyx in dural arteriovenous fistulas and adjunctive to surgery and radiotherapy. Location of the DAVFs affected the outcome of transarterial embolization.     

Transvenous balloon-assisted transarterial Onyx embolization of transverse–sigmoid dural arteriovenous malformation

Introduction

Endovascular treatment of dural arteriovenous malformation is challenging especially if the related dural venous sinus is patent and might be usable for normal venous drainage.

Methods

A new particular venous balloon remodeling technique was described in the treatment of transverse–sigmoid dural arteriovenous malformation by using transarterial Onyx. The goal was obliteration of the malformation with preservation of the dural sinus. Two illustrative cases with 6-month follow-up result were narrated.

Results

The penetration of Onyx in the dural arterial feeders was well achieved. Obliteration of the malformation with preservation of the dural sinus was finally demonstrated.

Conclusion

Transvenous balloon assistance is a useful and feasible technique in the treatment of dural arteriovenous malformation when sinus preservation is in concern.     

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.Dural arteriovenous fistulas (DAVFs) are the abnormal vascular shunts of dura mater that are usually found within or near the wall of dural venous sinuses [1]. Nevertheless, the location of DAVF lesions is not constant; it can occur in any part of dura and its subsidiaries. With the development of newer techniques and embolic materials in the world of interventional neuroradiology, endovascular therapy has now been developing as the primary treatment strategy to cure DAVFs, with successful results [2]. However, depending upon the location of fistula, its venous drainage pattern and it feeding vessels, approaching vascular pathways has to be considered carefully. Patients may present with intracranial haemorrhage, intracranial hypertension or brain herniation and other serious consequences depending upon the cortical venous reflux (CVR) pattern [3,4].For satisfactory embolisation of either type of DAVF, embolic material that can adequately disperse into whole fistulous channels is required. Onyx 18, which is made up of 6% ethylene vinyl alcohol (ensuring that it can travel distally and penetrate deep into a target area, owing to its low viscosity) (ev3, Plymouth, MN) is a similar kind of non-adhesive liquid embolic agent having better penetration quality and has been widely used for the treatment of cerebral arteriovenous malformations [5]. However, literature about the use of Onyx 18 via either pathway to embolise DAVF is still limited.Here we presente our preliminary experience about the use of Onyx 18 together with coils via arterial and venous pathways to embolise non-cavernous (ncsDAVF) and cavernous sinus dural arteriovenous fistulas (csDAVF), and their short-term outcome evaluation. We have detailed the embolisation techniques, their effectiveness and related complications.     

Angioarchitecture of Transverse-Sigmoid Sinus Dural Arteriovenous Fistulas: Evaluation of Shunted Pouches by Multiplanar Reformatted Images of Rotational Angiography

BACKGROUND AND PURPOSE:Recognition of shunted pouches dural arteriovenous fistula allows us to treat the disease effectively by selective embolization of the pouches at first. However, the shunted pouches in transverse-sigmoid sinus dural arteriovenous fistulas have not been well-documented. Our aim was to evaluate the angioarchitecture of transverse-sigmoid sinus dural arteriovenous fistulas, including the frequency and location of shunted pouches and their feeding arteries.MATERIALS AND METHODSTwenty-five consecutive cases of TSS-DAVFs that underwent rotational angiography and transvenous embolization between 2008 and 2011 were reviewed. Multiplanar reformatted images of rotational angiography and selective angiography were reviewed with a particular focus on the shunted pouches.RESULTS:All 25 cases showed SPs, with numbers ranging from 1 to 4 pouches (mean, 2.35). The SPs were located at the transverse-sigmoid junction in 16, close to the vein of Labbé in 9, at the dorsal-to-sigmoid sinus in 9, inferior to the sigmoid sinus in 6, at the sigmoid-jugular junction in 5, and inferior to the transverse sinus or the sinus confluence in 14. The SP at the sigmoid sinus was frequently fed by the jugular branch of the ascending pharyngeal artery and the stylomastoid artery. The SP at the transverse-sigmoid junction and the vein of Labbé was fed by the petrosal/petrosquamous and posterior branches of the middle meningeal artery and the transosseous branches of the occipital artery. The SP inferior to the transverse sinus and the sinus confluence was fed by the transosseous branches of the occipital artery and the posterior meningeal artery. All cases were successfully treated by transvenous embolization with sinus packing (n = 13) or selective embolization of the SP (n = 12).CONCLUSIONS:The presence of SP is a common angioarchitecture of TSS-DAVFs. Identification of the SPs would be useful for their treatment.

Transverse-sigmoid sinus dural arteriovenous fistula is one of the most common types of intracranial DAVFs and can lead to various disorders, from tinnitus to fatal cerebral hemorrhage. A majority of TSS-DAVFs have been treated by endovascular techniques, including transarterial embolization and/or transvenous embolization. The drainage pattern of the TSS-DAVFs is strongly related to the clinical symptoms; therefore, the importance of evaluating the drainage routes of the TSS-DAVF before treatment has been well-recognized.^1,2 However, other angioarchitectures, such as fistulous points and dural sinus compartments, have not been well-documented. Some cases of TSS-DAVFs can be successfully treated by selective embolization of a fistulous portion with preservation of the normal sinus lumen.^3–5 Although these cases are generally thought to be special, 1 study showed that the fistulous compartment of the dural sinus often exists in and around the dural sinus in TSS-DAVFs.⁶Recent developments in 3D angiography technology allow us to evaluate the angioarchitecture of DAVFs more easily and precisely.⁷ In this study, we evaluated the angioarchitecture of TSS-DAVFs, including the frequency and location of these fistulous compartments of dural sinuses on the basis of MPR images of rotational angiography. Additionally, we discuss the endovascular techniques for the treatment of TSS-DAVFs. Several different terms have been used to refer to these fistulous portions located outside the main lumen of the dural sinus, including venous recipients of DAVFs, dural sinus septations, accessory sinuses, parallel channels, parallel sinuses, and fistulous drainage. In this article, we use the term “shunted pouch” to refer to these structures.     

Endovascular Treatment of Dural Arteriovenous Fistulas of the Transverse and Sigmoid Sinuses Using Transarterial Balloon-Assisted Embolization Combined with Transvenous Balloon Protection of the Venous Sinus

BACKGROUND AND PURPOSE:Combined transarterial balloon-assisted endovascular embolization with double-lumen balloon microcatheters and concomitant transvenous balloon protection was described as a promising treatment technique for dural arteriovenous fistulae of the transverse and sigmoid sinus. The purpose of this study was to evaluate the technical efficacy and safety of this combined treatment technique.MATERIALS AND METHODS:Nine consecutive patients presenting with dural arteriovenous fistulas of the transverse and sigmoid sinuses underwent combined transarterial and transvenous balloon-assisted endovascular embolization. Prospectively collected data were reviewed to assess the technical success rate, complication rate, and clinical outcome.RESULTS:Six patients presented with clinically symptomatic Borden type I, and 3 patients, with Borden type II dural arteriovenous fistulas of the transverse and sigmoid sinuses (3 men, 6 women; mean age, 50.4 years). Transarterial embolization was performed with a double-lumen balloon with Onyx and concomitant transvenous sinus protection with a dedicated venous remodeling balloon. Complete angiographic occlusion at the latest follow-up (mean, 4.8 months) was achieved in 6 patients, and near-complete occlusion, in 2 patients. Clinical cure or remission of symptoms was obtained in 6 and 2 patients, respectively. One patient with a residual fistula underwent further treatment in which the dural arteriovenous fistula was cured by sinus occlusion. Complete occlusion of the dural arteriovenous fistula was visible on the follow-up angiography after final treatment in 8 patients. One patient refused follow-up angiography but was free of symptoms. There were no immediate or delayed postinterventional complications.CONCLUSIONS:Transarterial balloon-assisted embolization of dural arteriovenous fistulas of the transverse and sigmoid sinuses with combined transvenous balloon protection is safe and offers a high rate of complete dural arteriovenous fistula occlusion and remission of clinical symptoms.

During the past few decades, endovascular embolization has become the first-line treatment for a wide range of dural arteriovenous fistulas (dAVFs). Several transarterial and transvenous endovascular approaches have been advocated. Preliminary studies on the use of double-lumen balloon microcatheters for transarterial embolization of dAVFs with Onyx (Covidien, Irvine, California) have shown encouraging results. These studies have reported high occlusion rates, reduction of reflux into the feeding artery, a reduced quantity of injected Onyx and peri-interventional time, and low complication rates.^1–9 In addition, transvenous balloon-assisted sinus protection during transarterial embolization has been reported to be another useful adjunct to the endovascular treatment of dAVFs.^10–12 Transvenous balloon protection of the recipient sinus has mainly been associated with a reduction in inadvertent occlusion of the lumen of a functioning sinus, preservation of venous patency, facilitation of occlusion of abnormal arteriovenous connections within the sinus wall and separate venous channels, and increased penetration of embolic material by retrograde reflux into other dural feeders of the fistula network. Techniques aiming to preserve the underlying sinus may have lower complication rates than sinus-occluding embolization techniques, in which the recipient venous sinus has to be sacrificed.¹³ Therefore, transarterial balloon-assisted embolization with a concomitant transvenous balloon protection technique theoretically has the advantages of both techniques combined; this combination leads to increased occlusion and reduced complication rates.The purpose of this study was to report the angiographic and clinical outcomes of patients with dAVFs of the transverse and sigmoid sinuses treated with a combined approach of transarterial balloon-assisted endovascular embolization and double-lumen balloon microcatheters with concomitant transvenous balloon protection.     

Preliminary experience with onyx embolization for the treatment of intracranial dural arteriovenous fistulas

BACKGROUND AND PURPOSE: Onyx was recently approved for the treatment of pial arteriovenous malformations, but its use to treat dural arteriovenous fistulas (DAVFs) is not yet well established. We now report on the treatment of intracranial DAVFs using this nonadhesive liquid embolic agent.MATERIALS AND METHODS: We performed a retrospective analysis of 12 consecutive patients with intracranial DAVFs who were treated with Onyx as the single treatment technique at our institution between March 2006 and February 2007.RESULTS: A total of 17 procedures were performed in 12 patients. In all of the cases, transarterial microcatheterization was performed, and Onyx-18 or a combination of Onyx-18/Onyx-34 was used. Eight patients were men. The mean age was 56 ± 12 years. Nine patients were symptomatic. There was an average of 5 feeders per DAVF (range, 1–9). Cortical venous reflux was present in all of the cases except for 1 of the symptomatic patients. Complete resolution of the DAVF on immediate posttreatment angiography was achieved in 10 patients. The remaining 2 patients had only minimal residual shunting postembolization, 1 of whom appeared cured on a follow-up angiogram 8 weeks later. The other patient has not yet had angiographic follow-up. Follow-up angiography (mean, 4.4 months) is currently available in 9 patients. There was 1 angiographic recurrence (asymptomatic), which was subsequently re-embolized with complete occlusion of the fistula and its draining vein. There was no significant morbidity or mortality.CONCLUSION: In our experience, the endovascular treatment of intracranial DAVFs with Onyx is feasible, safe, and highly effective with a small recurrence rate in the short-term follow-up.

Dural arteriovenous fistulas (DAVFs) are acquired abnormal arteriovenous connections within the dura that account for 10%–15% of all intracranial arteriovenous malformations (AVMs).¹ The origin of these malformations is not entirely understood but has been associated with several conditions including venous thrombosis, intracranial surgery, tumor, puerperium, and trauma.² DAVFs may be asymptomatic or present with symptoms that range from tinnitus to intracranial hemorrhage (ICH) and severe neurologic deficits. Their behavior is fundamentally determined by the venous drainage pattern. Retrograde leptomeningeal or cortical venous drainage has a strong correlation with adverse clinical events: such patients are thought to have an annual risk of aggressive neurologic presentation of 15% resulting in an annual mortality of 10.4%.³ Moreover, rebleeding rates may be as high as 35% over the first 2 weeks after the initial hemorrhage.⁴ Thus, the DAVFs that have these features require treatment.The current management of DAVFs includes endovascular, surgical, and radiosurgical treatments, either alone or in combination. Endovascular therapy is typically performed with cyanoacrylate, ethyl alcohol, coils, and/or particles. Onyx (ev3, Irvine, Calif), an ethylene vinyl alcohol copolymer preparation, was recently approved for the treatment of pial AVMs, but its use to treat DAVFs is not yet well established. We report our preliminary experience with the endovascular treatment of intracranial DAVFs using this nonadhesive liquid embolic agent.     

Transarterial Onyx Embolization of Cranial Dural Arteriovenous Fistulas: Long-Term Follow-Up

BACKGROUND AND PURPOSE:Endovascular therapy with liquid embolic agents is a common treatment strategy for cranial dural arteriovenous fistulas. This study evaluated the long-term effectiveness of transarterial Onyx as the single embolic agent for curative embolization of noncavernous cranial dural arteriovenous fistulas.MATERIALS AND METHODS:We performed a retrospective review of 40 consecutive patients with 41 cranial dural arteriovenous fistulas treated between March 2006 and June 2012 by using transarterial Onyx embolization with intent to cure. The mean age was 57 years; one-third presented with intracranial hemorrhage. Most (85%) had cortical venous drainage. Once angiographic cure was achieved, long-term treatment effectiveness was assessed with DSA and clinical follow-up.RESULTS:Forty-nine embolization sessions were performed; 85% of cranial dural arteriovenous fistulas were treated in a single session. The immediate angiographic cure rate was 95%. The permanent neurologic complication rate was 2% (mild facial palsy). Thirty-five of the 38 patients with initial cure underwent short-term follow-up DSA (median, 4 months). The short-term recurrence rate was only 6% (2/35). All patients with occlusion at short-term DSA undergoing long-term DSA (median, 28 months) had durable occlusion. No patient with long-term clinical follow-up (total, 117 patient-years; median, 45 months) experienced hemorrhage.CONCLUSIONS:Transarterial embolization with Onyx as the single embolic agent results in durable long-term cure of noncavernous cranial dural arteriovenous fistulas. Recurrence rates are low on short-term follow-up, and all patients with angiographic occlusion on short-term DSA follow-up have experienced a durable long-term cure. Thus, angiographic cure should be defined at short-term follow-up angiography instead of at the end of the final embolization session. Finally, long-term DSA follow-up may not be necessary if occlusion is demonstrated on short-term angiographic follow-up.

Endovascular therapy is commonly used for the treatment of noncavernous cranial dural arteriovenous fistulas (cDAVFs). Cyanoacrylates, ethyl alcohol, coils, and particles can be used alone or in combination via transarterial, transvenous, or occasionally direct percutaneous treatment routes. There is no US Food and Drug Administration–approved liquid embolic agent for the treatment of cDAVFs. The ethylene-vinyl alcohol copolymer liquid embolic system (Onyx; Covidien, Irvine, California) is FDA-approved for the presurgical embolization of brain arteriovenous malformations. Since Onyx has become available, transarterial embolization of cDAVFs by using Onyx as the sole endovascular embolic agent has become our preferred treatment strategy. This endovascular treatment approach represents an “off-label” use of the Onyx liquid embolic system.The immediate occlusion rate in large cohort studies of patients treated with transarterial Onyx embolization ranges from 62% to 92%, and short-term durable occlusion has been demonstrated.^1–4 We have previously reported our short-term experience using Onyx in these patients⁵ and have compared the success of this technique with embolization using n-butyl cyanoacrylate.⁶ However, there currently remain no published data on the long-term effectiveness for embolization of cDAVFs by using Onyx, to our knowledge. Here we report our long-term angiographic occlusion rate and clinical follow-up in a cohort of noncavernous cranial DAVFs that were treated by using transarterial Onyx embolization with the intention of complete cure.     

Transarterial Embolization of Type II Endoleaks after EVAR: The Role of Ethylene Vinyl Alcohol Copolymer (Onyx)

Purpose

To determine the feasibility and efficacy of transarterial endoleak embolization using the liquid embolic agent ethylene vinyl alcohol copolymer (Onyx).

Methods

Over a 7-year period eleven patients (6 women, 5 men; mean age 68 years, range 37–83 years) underwent transarterial embolization of a type II endoleak after endovascular aortic aneurysm repair using the liquid embolic agent Onyx. Two patients (18 %) had a simple type II endoleak with only one artery in communication with the aneurysm sac, whereas 9 patients (82 %) had a complex type II endoleak with multiple communicating vessels. We retrospectively analyzed the technical and clinical success of transarterial type II endoleak embolization with Onyx. Complete embolization of the nidus was defined as technical success. Embolization was considered clinically successful when volume of the aneurysm sac was stable or decreased on follow-up CT scans.

Result

Mean follow-up time was 26.0 (range 6–50) months. Clinical success was achieved in 8 of 11 patients (73 %). Transarterial nidus embolization with Onyx was technically successful in 6 of 11 patients (55 %). In three cases the nidus was embolized without direct catheterization from a more distal access through the network of collateral vessels.

Conclusion

Onyx is a favorable embolic agent for transarterial endoleak embolization. To achieve the best clinical results, complete occlusion of the nidus is mandatory.     

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.

Dural arteriovenous fistulas (DAVFs) account for 10%–15% of intracranial vascular malformations.^1,2 The most common location of an intracranial DAVF is the cavernous sinus, followed by the transverse-sigmoid sinus.^1–3 Major DAVF classification systems, such as the Cognard and Borden systems, grade DAVFs on the basis of venous drainage patterns, in which the presence of retrograde cortical venous drainage (CVD) indicates a higher risk of hemorrhage.^4–7 Cases of venous outlet obstruction playing a role in transforming benign (without CVD) into malignant DAVFs (with CVD) have been reported in the literature.⁸ Sinus stenosis (SS) is frequently associated with idiopathic intracranial hypertension.^9,10 Nevertheless, the incidence of SS and its association with DAVFs have not been thoroughly explored. SS can be found in DAVFs with retrograde or antegrade sinus flow, but its impact on cerebral hemodynamics has rarely been discussed. Theoretically, stenotic and thrombosed sinuses impede the venous outflow, and a DAVF itself increases overall blood volume in the affected sinus; the combination of the 2 hemodynamic disorders adversely affects venous flow and subsequently increases intracranial pressure and the risk of intracranial hemorrhage.Current treatment strategies for DAVFs in the transverse sinus include microsurgery, endovascular treatment, stereotactic radiosurgery (SRS), or their combinations.^11–13 Endovascular treatment has been the treatment of choice for DAVFs with CVD because it provides immediate curative results and minimizes the risk of hemorrhage.^14–16 Nevertheless, the complication rate of endovascular treatment is higher than that of SRS.^14,17,18 By contrast, SRS has hardly any periprocedural risks and achieves DAVF cure rates of between 58% and 73%. Although SRS can reduce the bleeding rate from 20% to 2% after shunting has been totally closed,¹⁹ the latent period for SRS ranges from 1 to 3 years and carries a 4.1% hemorrhagic rate in DAVFs with CVD.^3,20 Therefore, SRS is usually preferred for cases without CVD, and endovascular treatment is more suitable for immediately minimizing the risk of hemorrhage.Several studies have proposed a reconstructive method by using venoplasty and stent placement in combination with transarterial embolization to ameliorate or even cure DAVFs with venous outlet obstruction.^21–23 We wondered whether this approach could downgrade DAVFs with CVD—that is, to restore their normal cortical venous drainage and make them eligible for SRS, thereby minimizing the risk of hemorrhage during the latent period. Therefore, the purpose of the current study was to clarify the following: 1) the incidence of SS in different grades of DAVF in the transverse sigmoid sinus, 2) the impact of SS on DAVF hemodynamics by using quantitative DSA, and 3) the initial treatment results of venoplasty and/or stent placement followed by SRS.     

Endovascular treatment of intracranial dural arteriovenous fistulas with cortical venous drainage: new management using Onyx

BACKGROUND AND PURPOSE: DAVFs (dural arteriovenous fistulas) represent one of the most dangerous types of intracranial AV shunts. Most of them are cured by arterial or venous embolization, but surgery/radiosurgery can be required in case of failure. Our goal was to reconsider the endovascular treatment strategy according to the new possibilities of arterial embolization using non polymerizing liquid embolic agent.MATERIALS AND METHODS: Thirty patients were included in a prospective study during the interval between July 2003 and November 2006. Ten of these had type II, 8 had type III, and 12 had type IV fistulas. Sixteen presented with hemorrhage. Five had been treated previously with other embolic materials.RESULTS: Complete angiographic cure was obtained in 24 cases. Of these 24 cures, 20 were achieved after a single procedure. Cures were achieved in 23 of 25 patients who had not been embolized previously and in only 1 of 5 previously embolized patients. Among these 24 patients, 23 underwent a follow-up angiography, which has confirmed the complete cure. Partial occlusion was obtained in 6 patients, 2 were cured after additional surgery, and 2 underwent radiosurgery. Onyx volume injected per procedure ranged from 0.5 to 12.2 mL (mean, 2.45 mL). Rebleeding occurred in 1 completely cured patient at day 2 due to draining vein thrombosis. One patient had cranial nerve palsy that resolved. Two ethmoidal dural arteriovenous fistulas were occluded. All 10 of the patients with sinus and then CVR drainage were cured.CONCLUSION: Based on this experience, we believe that Onyx may be the treatment of choice for many patients with intracranial dural arteriovenous fistula (ICDAVF) with direct cortical venous reflux (CVR). The applicability of this new embolic agent indicates the need for reconsideration of the global treatment strategy for such fistulas.

Several studies have shown an association between intracranial (IC) dural arteriovenous fistula (DAVF) venous drainage patterns and clinical presentation.^1,2 DAVFs draining retrogradely into cortical veins exhibit a much higher incidence of hemorrhage or venous infarction.^3,4 The annual mortality rate for cortical venous reflux (CVR) may be as high as 10.4%, whereas the annual risk for hemorrhage or nonhemorrhagic neurologic deficits during follow-up are 8.1% and 6.9%, respectively, resulting in an annual event rate of 15%.⁴ In subjects presenting with hemorrhage, the risk of rebleeding has been evaluated at 35% in the 2 weeks after the initial hemorrhage.³ Consequently, DAVFs with CVR require treatment aimed at a complete and definitive fistula closure. In general, treatment of such fistulas primarily involves an endovascular approach, and if this fails, surgical or radiosurgical approaches are used. The present prospective study investigated the use of a new nonadhesive liquid embolic agent, Onyx (ev3, Irvine, Calif), in the treatment of DAVF with CVR.     

Non-contrast-enhanced 4D MR angiography with STAR spin labeling and variable flip angle sampling: a feasibility study for the assessment of Dural Arteriovenous Fistula

Introduction

This study aimed to evaluate the feasibility of non-contrast-enhanced 4D magnetic resonance angiography (NCE 4D MRA) with signal targeting with alternative radiofrequency (STAR) spin labeling and variable flip angle (VFA) sampling in the assessment of dural arteriovenous fistula (DAVF) in the transverse sinus.

Methods

Nine patients underwent NCE 4D MRA for the evaluation of DAVF in the transverse sinus at 3 T. One patient was examined twice, once before and once after the interventional treatment. All patients also underwent digital subtraction angiography (DSA) and/or contrast-enhanced magnetic resonance angiography (CEMRA). For the acquisition of NCE 4D MRA, a STAR spin tagging method was used, and a VFA sampling was applied in the data readout module instead of a constant flip angle. Two readers evaluated the NCE 4D MRA data for the diagnosis of DAVF and its type with consensus. The results were compared with those from DSA and/or CEMRA.

Results

All patients underwent NCE 4D MRA without any difficulty. Among seven patients with patent DAVFs, all cases showed an early visualization of the transverse sinus on NCE 4D MRA. Except for one case, the type of DAVF of NCE 4D MRA was agreed with that of reference standard study. Cortical venous reflux (CVR) was demonstrated in two cases out of three patients with CVR.

Conclusion

NCE 4D MRA with STAR tagging and VFA sampling is technically and clinically feasible and represents a promising technique for assessment of DAVF in the transverse sinus. Further technical developments should aim at improvements of spatial and temporal coverage.     

A comparison of particulate and onyx embolization in preoperative devascularization of juvenile nasopharyngeal angiofibromas

Introduction

Juvenile nasopharyngeal angiofibromas (JNAs) are hypervascular tumors that may benefit from preoperative devascularization to reduce intraoperative blood loss (IBL). The purpose of this study was to compare transarterial particulate embolization (TAPE) with the direct percutaneous embolization (DPE) technique using ethylene vinyl alcohol (Onyx, ev3, Irvine, CA) for the preoperative devascularization of a JNA.

Methods

We retrospectively reviewed 50 consecutive JNA resections since 1995 for which preoperative embolization was either transarterial with particulate material (n?=?39) or DPE (n?=?11) using only Onyx. The IBL, transfusion requirements, operative time, and length of hospital admission were compared between the two groups.

Results

The mean IBL was 1,348.7?±?932.2 mL particulate group, 569.1?±?700.7 mL Onyx group (one-tailed Student’s t test p?=?0.003). The mean unit of packed red blood cells was 1.56?±?2.01 units particulate group, 0.45?±?1.04 units Onyx group (p?=?0.009). The relationship between embolization type and IBL remained significant or strongly correlated when accounting for the Fisch stage of the tumor (p?=?0.010 and p?=?0.056, respectively, by a multivariate least squares fit; alternately p?=?0.0003 and p?=?0.023, respectively, in the subset of patients with Fisch stage III tumors only). We also found that the proportion of resections for which an endoscopic approach could be used was significantly higher in the Onyx group than the particulate group (81.8 and 18.2 %; Pearson p?=?0.0002), and this was also significant both in our multivariate nominal logistic fit (p?<?0.001) and in the subset of patients with Fisch stage III tumors (p?=?0.018).

Conclusion

Pre-operative DPE with Onyx of a JNA when compared to TAPE significantly decreased IBL and RBC transfusion requirement during surgical resection. The proportion of surgical resections performed from an endoscopic approach was higher in the DPE Onyx group, which may have affected the results.     

The role of ethylene–vinyl alcohol copolymer in association with other embolic agents for the percutaneous and endovascular treatment of type Ia endoleak

Aim

To evaluate safety, technical and clinical success of embolization of type Ia endoleak (T1a EL) using ethylene–vinyl alcohol copolymer as embolic agent alone or in combination with other materials.

Materials and methods

Five patients presented T1a EL after endovascular repair of aortic aneurysms (EVAR) with radiological evidence of expanding sac size; in particular, three had contained rupture. In one patient, proximal cuff insertion was previously performed, in three patients proximal cuff was urgently inserted but T1a EL persisted; one patient, previously treated with Ovation Abdominal Stent Graft System, was directly proposed for endovascular treatment. In all cases, endovascular embolization was successfully performed and the transfemoral approach was always chosen; in one case it failed and translumbar approach by direct puncture of the sac was required. Used embolization agents were glue, ethylene–vinyl alcohol copolymer (Onyx) and coils in three cases, n-butyl cyanoacrylate and Onyx in one case, Onyx and coils in the last case.

Results

Technical success rate was 100% as well as clinical success. No major or minor complication, including non-target embolization, was registered. Clinical success was 100% until today and the sac diameter remained stable in four patients and decreased in one.

Conclusions

Onyx may be considered a suitable embolic agent in the treatment of patients with type Ia endoleaks after EVAR, after failure of conventional treatments such as prolonged balloon inflation of the aortic neck or deployment of large bare stent.

     

Migration of Bone Wax into the Sigmoid Sinus after Posterior Fossa Surgery

BACKGROUND AND PURPOSE:Bone wax is a hemostatic agent that has been reported in some instances to migrate into the sigmoid sinus following posterior fossa surgery. The purpose of this study was to characterize the CT and MR imaging findings of this entity.MATERIALS AND METHODS:The study included 212 consecutive patients who underwent posterior fossa surgery and postoperative CT and contrast-enhanced MR imaging. The presence of sigmoid sinus bone wax migration was determined with the following criteria: sigmoid sinus filling defect showing low signal on all MR imaging pulse sequences; sigmoid sinus filling defect showing low CT attenuation, similar to fat attenuation; and clinical confirmation that bone wax was used intraoperatively. CT and MR imaging of an in vitro bone wax sample was also performed.RESULTS:We identified 6 cases of sigmoid sinus bone wax migration. In each case, a low-signal-intensity, low-attenuation filling defect was noted in the sigmoid sinus. The morphology was linear (n = 3) or globular (n = 3). In patients with serial imaging, the appearance of migrated bone wax remained stable over time. No adverse outcomes related to sigmoid sinus bone wax migration were encountered. In vitro imaging of bone wax confirmed low CT attenuation and low MR imaging signal intensity on T1WI and T2WI.CONCLUSIONS:Bone wax migration into the sigmoid sinus is a recognizable imaging finding after posterior fossa surgery that appears to have a benign clinical course. The finding should be distinguished from more serious complications, such as venous sinus thrombosis.

Bone wax is commonly used during the course of posterior fossa craniotomy to control bleeding from emissary veins or to pack violated mastoid air cells. The mastoid emissary vein often lies close to or within the retrosigmoid or suboccipital craniotomy bed and represents a channel in direct communication with the sigmoid sinus.¹ Awareness of the use of this agent is important in assessing postoperative imaging because its presence within a dural venous sinus might be mistaken for air, fat, or thrombus. The particular imaging characteristics of this agent can aid appropriate diagnosis. The appearance has been reported in the literature as low attenuation on CT (intermediate between fat and simple fluid) and as a signal void on MR imaging (attributable to its semicrystalline solid nature).² To our knowledge, only 2 prior studies of sigmoid sinus bone wax migration (including 8 total cases) have been reported in the literature, and conventional MR imaging features of the migrated bone wax were reported in only 1 of these cases.^3,4 The purpose of our study was to describe the CT and MR imaging features of sigmoid sinus bone wax migration after posterior fossa surgery. We also sought to assess the CT and MR imaging features of an in vitro bone wax sample.     

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

Introduction  

Dural arteriovenous fistulae (DAVFs) are a potentially dangerous group of intracranial arteriovenous shunts with significant morbidity and mortality. Treatment has traditionally included transvenous and/or transarterial embolisation, which may be followed by surgical ligation. This study assesses the impact of Onyx on treatment.     

Postoperative Imaging Findings following Sigmoid Sinus Wall Reconstruction for Pulse Synchronous Tinnitus

BACKGROUND AND PURPOSE:Transmastoid sigmoid sinus wall reconstruction is a surgical technique increasingly used for the treatment of pulsatile tinnitus arising from sigmoid sinus wall anomalies. The imaging appearance of the temporal bone following this procedure has not been well-characterized. The purpose of this study was to evaluate the postoperative imaging appearance in a group of patients who underwent this procedure.MATERIALS AND METHODS:The medical records of 40 consecutive patients who underwent transmastoid sigmoid sinus wall reconstruction were reviewed. Thirteen of 40 patients underwent postoperative imaging. Nineteen CT and 7 MR imaging examinations were assessed for the characteristics of the materials used for reconstruction, the impact of these on the adjacent sigmoid sinus, and complications.RESULTS:Tinnitus resolved in 38 of 40 patients. Nine patients were imaged postoperatively for suspected complications, including dural sinus thrombosis, facial swelling, and wound drainage. Two patients underwent imaging for persistent tinnitus, and 2, for development of tinnitus on the side contralateral to the side of surgery. The materials used for reconstruction (NeuroAlloderm, HydroSet, bone pate) demonstrated characteristic imaging appearances and could be consistently identified. In 5 of 13 patients, there was extrinsic compression of the sigmoid sinus by graft material. Dural sinus thrombosis occurred in 2 patients.CONCLUSIONS:The imaging findings following sigmoid sinus wall repair are characteristic. Graft materials may result in extrinsic compression of the sigmoid sinus, and this finding may be confused with dural venous thrombosis. Awareness of the imaging characteristics of the graft materials used enables this differentiation.

Tinnitus may be categorized as subjective, when it originates in either the peripheral or central auditory system and is perceived only by the patient, or objective, when it arises from a mechanical somatosound.¹ Pulsatile, or pulse synchronous, tinnitus (PST) usually arises from the abnormal self-perception of one''s vascular flow. PST is a potentially disabling symptom, which may profoundly impact daily functioning.² Although PST can arise from a number of venous and arterial abnormalities,^2,3 venous PST accounts for most cases encountered in clinical practice.⁴It is increasingly recognized that sigmoid sinus wall anomalies, which include thinning and dehiscence of the sigmoid sinus plate with or without an associated diverticulum, are a frequently encountered and surgically correctable cause of PST.^5–7 Both open surgical and endovascular interventions have proved successful in the amelioration of PST in such patients.^8–10 Sigmoid sinus wall reconstruction (SSWR) is increasingly being performed via an extraluminal, transmastoid approach.¹¹ The goal of the procedure is to bridge the bony dehiscence and reconstruct the wall of the sinus, thereby eliminating audible turbulence and interrupting the transmission of mural vibrations via the mastoid air cells. The purpose of this study was to describe the imaging findings in patients who have undergone SSWR and to evaluate the imaging characteristics of complications arising from this procedure.     

Transvenous balloon-assisted Onyx embolization of dural arteriovenous fistulas of hypoglossal canal

Purpose

This retrospective study summarized the technique aspects and effectiveness of transvenous balloon-assisted Onyx embolization treating selected dural arteriovenous fistulas of hypoglossal canal (HCDAVFs).

Methods

Eight patients of HCDAVFs from January 2010 to December 2016 in a single institution were reviewed retrospectively. There were six males and two females aged from 30 to 69 years (mean age, 52.8 years). Eight patients presented with pulsatile tinnitus, four associated with ocular symptom, and one accompanied with tongue muscle atrophy. All lesions were with accessible venous approach from ipsilateral internal jugular vein. The microcatheter was positioned in the venous pouch from internal jugular vein; the remodeling balloon was advanced from internal jugular vein into inferior petrosal sinus. The balloon having 4 mm in diameter and 15 mm in length was inflated to temporarily block the antegrade venous drainage from fistulous pouch to internal jugular vein during the injection of Onyx. Approximately 1- to 2.1-ml Onyx-18 was used as the sole embolic material to obliterate the lesions.

Results

All lesions were occluded completely in a single-session embolization without procedural complications and postoperative new symptom. The follow-up period ranged from 6 to 13 months. Preoperative ocular symptom and tinnitus were resolved completely in all patients. The follow-up angiograms of three patients demonstrated durable occlusion.

Conclusions

Our experience in this small series of patients indicated transvenous balloon-assisted Onyx embolization was a feasible and effective option for treating selected HCDAVFs.

     

Endovascular treatment of dural fistulas with the venous outflow of laterocavernous sinus

Objective

To report our findings concerning the laterocavernous sinus (LCS) drainage of dural fistulas, focusing our attention on the important implications in treatment of the LCS, which is one of the principal drainage pathways of the superficial middle cerebral vein (SMCV).

Methods

Consecutive 32 patients with dural fistulas treated endovascularly between 2005 and 2008 were reviewed. Seven patients had angiographic features such as dural fistulas draining with SMCV via LCS. Clinical records for these 7 patients were focused to determine their presenting symptoms, angiographic features, endovascular treatments, and clinical outcomes.

Results

Over 3 years, 7 patients had 7 dural fistulas drained with SMCV via LCS were treated. Six-vessel angiography confirmed the presence of the dural fistulas. All fistulas were Cognard Type III featured by leptomeningeal veins drainage. One fistula involving the lesser sphenoid wing and 6 fistulas involving CS were supplied by external carotid artery branches with or without dural branches of the internal carotid artery. LCS was identified as a contiguous to SMCV drainage in these cases. One patient was treated with transvenous coil embolization alone, two with transvenous a combination of Onyx and coil embolization, and 4 with transarterial embolization. An angiographic obliteration and clinical cure was achieved in all patients. Complication was local hair loss due to X-ray radiation in one patient.

Conclusion

It is very important to diagnose the presence of LCS in dural fistulas during the diagnostic angiography. It is believed that the knowledge of LCS might be relevant for the understanding and treatment of dural fistulas involving the LCS.