DOI: 10.1148/rg.246045026
RadioGraphics 2004;24:1637-1653
© RSNA, 2004
Treatment of Intracranial Dural Arteriovenous Fistulas: Current Strategies Based on Location and Hemodynamics, and Alternative Techniques of Transcatheter Embolization1
Hiro Kiyosue, MD,
Yuzo Hori, MD,
Mika Okahara, MD,
Shuichi Tanoue, MD,
Yoshiko Sagara, MD,
Shunro Matsumoto, MD,
Hirofumi Nagatomi, MD and
Hiromu Mori, MD
1 From the Department of Radiology, Oita Medical University, 1–1 Hasama, Oita, 879–55, Japan (H.K., Y.H., M.O., S.T., Y.S., S.M., H.M.); and the Department of Neurosurgery, Nagatomi Neurosurgical Hospital, Oita, Japan (H.N.). Recipient of a Cum Laude award for an education exhibit at the 2003 RSNA scientific assembly. Received March 1, 2004; revision requested April 20 and received June 3; accepted June 3. All authors have no financial relationships to disclose. Address correspondence to H.K. (e-mail: hkiyosue@med.oita-u.ac.jp).
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Abstract
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Intracranial dural arteriovenous fistulas (AVFs) can occur anywhere within the dura mater. Patients may be clinically asymptomatic or may experience symptoms ranging from mild symptoms to fatal hemorrhage, depending on the location (eg, cavernous sinus, transverse-sigmoid sinus, tentorium, superior sagittal sinus, anterior fossa) and venous drainage pattern of the AVF. In the past, dural AVFs have been treated with a variety of approaches, including surgical resection, venous clipping, transcatheter embolization, radiation therapy, or a combination of these treatments. Recent developments in catheter intervention now allow most patients to be cured with transcatheter embolization, although stereotactic radiation therapy is demonstrating good results in an increasing number of cases and surgery is still the preferred option in some cases. Familiarity with drainage patterns, the risk of aggressive symptoms, recent technical advances, and current treatment strategies is essential for the treatment of intracranial dural AVFs.
© RSNA, 2004
Index Terms: Angiography, 17.124 • Arteries, therapeutic embolization, 17.1264 • Arteriovenous malformations, dural, 17.75 • Cavernous sinus, 176.757 • Fistula, arteriovenous, 17.757 • Fistula, therapeutic embolization, 17.1264 • Sinuses, dural, 176.757 • Sinuses, superior sagittal, 176.757 Veins, therapeutic embolization, 17.1264
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LEARNING OBJECTIVES
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After reading this article and taking the test, the reader will be able to:
- Describe recent therapeutic results of treatment options for dural arteriovenous fistulas in various locations.
- Discuss current strategies in the treatment of intracranial dural arteriovenous fistulas.
- List alternative techniques of transcatheter embolization for treatment of intracranial dural arteriovenous fistulas.
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Introduction
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Intracranial dural arteriovenous fistulas (AVFs) represent 10%–15% of all intracranial vascular malformations. Although dural AVFs can occur anywhere in the dura mater covering the brain, they occur most frequently in the cavernous and transverse-sigmoid sinuses (Fig 1). Patients may be asymptomatic or may experience symptoms ranging from mild symptoms to fatal hemorrhage. Furthermore, these symptoms may be characterized as either nonaggressive (benign) (eg, tinnitus) or aggressive (eg, intracranial hemorrhage, neurologic deficits) (Table 1) (1–4). For many years, researchers have attempted to identify the factors that predispose to the risk of aggressive dural AVF symptoms (3–9). On the basis of their findings, it is now generally accepted that the venous drainage pattern of dural AVFs is the most predictive factor (3,4,7,9–11). Although several classification systems have been developed to grade the risks of dural AVFs, those devised by Cognard et al (3) and Borden et al (8) are the most widely used (Tables 2, 3). Dural AVFs that drain via the retrograde leptomeningeal cortical venous drainage channel show a significantly high rate of aggressive symptoms. Although dural AVF location is not directly correlated with aggressive behavior, the propensity for dangerous drainage patterns found at initial diagnosis does vary with location (3). Difficulties associated with treatment methods and proposed techniques, including limited access during interventional and surgical procedures, also differ depending on location: They are similar for dural AVFs of the transverse-sigmoid sinus and superior sagittal sinus and are unique for dural AVFs of the cavernous sinus, tentorium, and anterior fossa. Furthermore, the efficacy of irradiation also differs depending on location and drainage pattern.
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Figure 1a. Drawings (a = lateral view, b = anteroposterior view) illustrate the most common locations of dural AVFs: 1 = cavernous sinus (CS) (20%-40% of cases), 2 = transverse-sigmoid sinus (TS, SS) (20%-60%), 3 = tentorium (12%-14%), 4 = superior sagittal sinus (SSS) (8%), and 5 = anterior fossa (2%-3%). IPS = inferior petrosal sinus, ISS = inferior sagittal sinus, JV = jugular vein, MS = marginal sinus, OS = occipital sinus, SPS = superior petrosal sinus.
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Figure 1b. Drawings (a = lateral view, b = anteroposterior view) illustrate the most common locations of dural AVFs: 1 = cavernous sinus (CS) (20%-40% of cases), 2 = transverse-sigmoid sinus (TS, SS) (20%-60%), 3 = tentorium (12%-14%), 4 = superior sagittal sinus (SSS) (8%), and 5 = anterior fossa (2%-3%). IPS = inferior petrosal sinus, ISS = inferior sagittal sinus, JV = jugular vein, MS = marginal sinus, OS = occipital sinus, SPS = superior petrosal sinus.
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In this article, we discuss and illustrate general approaches to the treatment of dural AVFs. We also discuss current strategies in the treatment of dural AVFs based on location (cavernous sinus, transverse-sigmoid sinus, tentorium, superior sagittal sinus, anterior fossa) and drainage pattern, as well as alternative techniques of curative transcatheter embolization. We reviewed 32 cases of dural AVF from the past 5 years using diagnostic and interventional record databases and surgical records at our institutions.
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General Treatment Approaches
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General approaches for the treatment of dural AVFs include conservative treatment, radiation therapy, endovascular intervention, and surgery.
Conservative Treatment
The spontaneous regression of dural AVFs has been reported (12–14). Such an observation, which might be caused by thrombosis of the sinus or fistula, is frequently associated with cavernous sinus dural AVFs; therefore, some dural AVFs can be treated conservatively.
Radiation Therapy
Recent studies of the efficacy of stereotactic radiosurgery have reported relatively good results, with complete occlusion in 44%–87% of cases without serious complications (15–23). Advantages of this technique include decreased invasiveness and fewer short-term complications, whereas a disadvantage is the delayed response (approximately 6–12 months) after irradiation. The combined use of stereotactic radiosurgery and transarterial embolization (TAE) with particles can enhance the effectiveness of this technique and reduce the risk of worsening symptoms during the follow-up period (18,19,23).
Endovascular Intervention
TAE with Particles.—
Feeding artery embolization of external carotid branches with particles is easily performed and can reduce shunt flow. However, complete cures are difficult to achieve with this method because of the existence of feeding arteries that cannot be catheterized and the recruitment of a blood supply from collateral arteries (24). Therefore, this method is generally used to relieve symptoms or in combination with other procedures such as irradiation, surgery, or transvenous embolization (TVE).
Transvenous Coil Embolization.—
TVE with coils is used for curative purposes, and many studies have reported it to be very useful (complete occlusion in 80%–100% of cases) (25). However, serious complications associated with vessel injury and intracranial hemorrhage have also been reported (Fig 2) (26,27). Inadequate embolization leads to a worsening of symptoms. Critical assessment of diagnostic images and clinical conditions is also important for successful procedures.
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Figure 2a. Complication associated with subdural hematoma from TVE. (a) Left external carotid arteriogram shows a transverse sinus dural AVF fed by the left occipital, superficial temporal, and middle meningeal arteries. The AVF drains into the left jugular vein and cortical veins. (b) Left internal carotid arteriogram shows two dural AVFs (arrows) fed by the left ascending pharyngeal artery and the meningohypophyseal artery, respectively. The AVFs drain into the superior petrosal sinus (arrowheads). (c) Fluoroscopic image obtained during placement of a coil into the superior venous pouch contiguous with the superior petrous sinus demonstrates that the distal edge of the coil did not form a loop (arrow). As a result, the coil probably penetrated the venous wall. The transverse sinus and inferior venous pouch around the superior petrous sinus were already packed with coils. (d) Computed tomographic (CT) scan obtained 1 day after embolization shows a subdural hematoma at the left cerebral convexity and the falx. The patient complained of headache for a few days but fortunately did not have any neurologic symptoms. (e) Follow-up angiogram of the left external carotid artery shows complete obliteration of the transverse-sigmoid sinus dural AVF. (f) Left internal carotid arteriogram shows complete obliteration of the dural AVFs involving the superior petrosal sinus.
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Figure 2b. Complication associated with subdural hematoma from TVE. (a) Left external carotid arteriogram shows a transverse sinus dural AVF fed by the left occipital, superficial temporal, and middle meningeal arteries. The AVF drains into the left jugular vein and cortical veins. (b) Left internal carotid arteriogram shows two dural AVFs (arrows) fed by the left ascending pharyngeal artery and the meningohypophyseal artery, respectively. The AVFs drain into the superior petrosal sinus (arrowheads). (c) Fluoroscopic image obtained during placement of a coil into the superior venous pouch contiguous with the superior petrous sinus demonstrates that the distal edge of the coil did not form a loop (arrow). As a result, the coil probably penetrated the venous wall. The transverse sinus and inferior venous pouch around the superior petrous sinus were already packed with coils. (d) Computed tomographic (CT) scan obtained 1 day after embolization shows a subdural hematoma at the left cerebral convexity and the falx. The patient complained of headache for a few days but fortunately did not have any neurologic symptoms. (e) Follow-up angiogram of the left external carotid artery shows complete obliteration of the transverse-sigmoid sinus dural AVF. (f) Left internal carotid arteriogram shows complete obliteration of the dural AVFs involving the superior petrosal sinus.
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Figure 2c. Complication associated with subdural hematoma from TVE. (a) Left external carotid arteriogram shows a transverse sinus dural AVF fed by the left occipital, superficial temporal, and middle meningeal arteries. The AVF drains into the left jugular vein and cortical veins. (b) Left internal carotid arteriogram shows two dural AVFs (arrows) fed by the left ascending pharyngeal artery and the meningohypophyseal artery, respectively. The AVFs drain into the superior petrosal sinus (arrowheads). (c) Fluoroscopic image obtained during placement of a coil into the superior venous pouch contiguous with the superior petrous sinus demonstrates that the distal edge of the coil did not form a loop (arrow). As a result, the coil probably penetrated the venous wall. The transverse sinus and inferior venous pouch around the superior petrous sinus were already packed with coils. (d) Computed tomographic (CT) scan obtained 1 day after embolization shows a subdural hematoma at the left cerebral convexity and the falx. The patient complained of headache for a few days but fortunately did not have any neurologic symptoms. (e) Follow-up angiogram of the left external carotid artery shows complete obliteration of the transverse-sigmoid sinus dural AVF. (f) Left internal carotid arteriogram shows complete obliteration of the dural AVFs involving the superior petrosal sinus.
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Figure 2d. Complication associated with subdural hematoma from TVE. (a) Left external carotid arteriogram shows a transverse sinus dural AVF fed by the left occipital, superficial temporal, and middle meningeal arteries. The AVF drains into the left jugular vein and cortical veins. (b) Left internal carotid arteriogram shows two dural AVFs (arrows) fed by the left ascending pharyngeal artery and the meningohypophyseal artery, respectively. The AVFs drain into the superior petrosal sinus (arrowheads). (c) Fluoroscopic image obtained during placement of a coil into the superior venous pouch contiguous with the superior petrous sinus demonstrates that the distal edge of the coil did not form a loop (arrow). As a result, the coil probably penetrated the venous wall. The transverse sinus and inferior venous pouch around the superior petrous sinus were already packed with coils. (d) Computed tomographic (CT) scan obtained 1 day after embolization shows a subdural hematoma at the left cerebral convexity and the falx. The patient complained of headache for a few days but fortunately did not have any neurologic symptoms. (e) Follow-up angiogram of the left external carotid artery shows complete obliteration of the transverse-sigmoid sinus dural AVF. (f) Left internal carotid arteriogram shows complete obliteration of the dural AVFs involving the superior petrosal sinus.
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Figure 2e. Complication associated with subdural hematoma from TVE. (a) Left external carotid arteriogram shows a transverse sinus dural AVF fed by the left occipital, superficial temporal, and middle meningeal arteries. The AVF drains into the left jugular vein and cortical veins. (b) Left internal carotid arteriogram shows two dural AVFs (arrows) fed by the left ascending pharyngeal artery and the meningohypophyseal artery, respectively. The AVFs drain into the superior petrosal sinus (arrowheads). (c) Fluoroscopic image obtained during placement of a coil into the superior venous pouch contiguous with the superior petrous sinus demonstrates that the distal edge of the coil did not form a loop (arrow). As a result, the coil probably penetrated the venous wall. The transverse sinus and inferior venous pouch around the superior petrous sinus were already packed with coils. (d) Computed tomographic (CT) scan obtained 1 day after embolization shows a subdural hematoma at the left cerebral convexity and the falx. The patient complained of headache for a few days but fortunately did not have any neurologic symptoms. (e) Follow-up angiogram of the left external carotid artery shows complete obliteration of the transverse-sigmoid sinus dural AVF. (f) Left internal carotid arteriogram shows complete obliteration of the dural AVFs involving the superior petrosal sinus.
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Figure 2f. Complication associated with subdural hematoma from TVE. (a) Left external carotid arteriogram shows a transverse sinus dural AVF fed by the left occipital, superficial temporal, and middle meningeal arteries. The AVF drains into the left jugular vein and cortical veins. (b) Left internal carotid arteriogram shows two dural AVFs (arrows) fed by the left ascending pharyngeal artery and the meningohypophyseal artery, respectively. The AVFs drain into the superior petrosal sinus (arrowheads). (c) Fluoroscopic image obtained during placement of a coil into the superior venous pouch contiguous with the superior petrous sinus demonstrates that the distal edge of the coil did not form a loop (arrow). As a result, the coil probably penetrated the venous wall. The transverse sinus and inferior venous pouch around the superior petrous sinus were already packed with coils. (d) Computed tomographic (CT) scan obtained 1 day after embolization shows a subdural hematoma at the left cerebral convexity and the falx. The patient complained of headache for a few days but fortunately did not have any neurologic symptoms. (e) Follow-up angiogram of the left external carotid artery shows complete obliteration of the transverse-sigmoid sinus dural AVF. (f) Left internal carotid arteriogram shows complete obliteration of the dural AVFs involving the superior petrosal sinus.
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TAE with n-butyl-2-cyanoacrylate.—
TAE with n-butyl-2-cyanoacrylate has been applied to complex dural AVFs that are not accessible with percutaneous transvenous catheterization. Some authors emphasize techniques that involve wedging a microcatheter into the main feeding artery to inject a diluted (20%–25%) mixture of n-butyl-2-cyanoacrylate and iodized oil, and the preparatory devascularization of other minor feeding arteries by embolization with polyvinyl alcohol particles to avoid fragmentation of the glue column by competing inflows (28). Although results are relatively good, TAE with n-butyl-2-cyanoacrylate requires experience in using this material, and some authors have reported a 5%–20% complication rate (29). Other options such as surgical approaches and a combination of TAE and radiosurgery should also be considered when treating complex dural AVFs.
Stent Placement.—
Recently, some authors reported on the use of stent placement with restrictive changes of the sinuses in the treatment of dural AVFs in a small number of patients (30–32). Theoretically, the radial force of the stent can restore antegrade sinus flow and close shunts within the sinus wall. Although some dural AVFs have been successfully treated with stents, the long-term results are not yet known. Furthermore, currently available stents with sufficient diameter are relatively large (over 6 F) and have a stiff shaft. It is often difficult to introduce the stent into the affected area of the sinus due to the acute angle of the sigmoid sinus and the irregular narrowing of the lesion.
Surgery.—
Thanks to recent technical developments, interventional procedures have become a first-line treatment for dural AVFs. However, some difficult cases require surgical techniques (eg, sinus isolation and resection) in combination with interventional procedures; indeed, other cases, especially those involving dural AVFs of the anterior cranial fossa, can often be treated more easily and safely with surgical disconnection of the venous drainage (33).
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Cavernous Sinus Dural AVFs
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The most common symptoms of cavernous sinus dural AVF are ocular symptoms (eg, exophthalmos [proptosis]) caused by anterior venous drainage (Fig 3) (1,2,12,27,34). Aggressive neurologic symptoms such as intracranial hemorrhage are extremely rare because of the benign venous drainage pattern but can occur in association with dangerous venous drainage patterns, including (a) cortical venous reflux without other venous drainages (hemorrhagic infarction), (b) dominant deep venous drainage (hemorrhage, edema) (Fig 4), and (c) thrombosis of the central retinal vein(blindness) (24,25). Spontaneous regression of cavernous sinus dural AVFs is well recognized, being observed in 10%–50% of cases (2,13).
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Figure 3. Drawing shows venous drainage of cavernous sinus dural AVFs. 1 = anterior drainage into superior ophthalmic vein (SOV) and inferior ophthalmic vein (IOV), which can lead to ocular symptoms (eg, exophthalmos and chemosis); 2 = posteroinferior drainage into inferior petrous sinus (IPS), basilar plexus, and pterygoid plexus, leading to bruit and cranial nerve deficits; 3 = posterior drainage into superior petrous sinus (SPS), leading to bruit; 4 = cortical reflux into sphenoparietal sinus and superficial middle cerebral vein (SMV), leading to venous infarction and hemorrhage; 5 = cerebellar (spinal) drainage into petrous vein (PV), leading to ataxia and hemorrhage; and 6 = deep drainage into deep middle cerebral vein and uncal vein, leading to hemorrhage. JV = jugular vein, SS = sigmoid sinus, STV = superficial temporal vein.
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Figure 4a. Cavernous sinus dural AVF with dominant cerebellar venous drainage. (a) Right external carotid arteriogram shows a cavernous sinus dural AVF draining into the superior ophthalmic vein and cerebellar veins via the superior petrosal sinus (arrow). (b) Right external carotid arteriogram obtained after TVE through an occluded inferior petrosal sinus shows obliteration of the dural AVF.
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Figure 4b. Cavernous sinus dural AVF with dominant cerebellar venous drainage. (a) Right external carotid arteriogram shows a cavernous sinus dural AVF draining into the superior ophthalmic vein and cerebellar veins via the superior petrosal sinus (arrow). (b) Right external carotid arteriogram obtained after TVE through an occluded inferior petrosal sinus shows obliteration of the dural AVF.
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Treatment Strategy
Treatment options include conservative treatment, irradiation, TAE with particles or cyanoacrylate, and TVE. Recent studies of stereotactic radiation therapy for cavernous sinus dural AVFs showed a relatively high occlusion rate for the AVF (70%–88%) several months after treatment without significant complications (15,20,23). TVE and TAE with n-butyl-2-cyanoacrylate showed a higher occlusion rate (80%–100%) immediately after the procedure; however, serious complications such as intracranial hemorrhage and cranial nerve deficits were also reported (25–27,35,36). The efficacy, potential risk, and difficulty of these treatment options are described in Table 4.
Because of the low prevalence of aggressive symptoms and the relatively high rates of spontaneous regression, it is suggested that the majority of cases be treated conservatively for 1–3 months (Fig 5) (3). However, cases with progressive symptoms and dangerous drainage patterns require more aggressive treatment (TVE or TAE with n-butyl-2-cyanoacrylate), and cases that have remained stable for a few months should be treated with irradiation or intervention. One should also be aware that the low-risk drainage patterns of dural AVFs develop into high-risk patterns with progressive thrombosis or restriction of the cavernous sinus outlet (Fig 6) (37).
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Figure 5a. Spontaneous regression of a cavernous sinus dural AVF with posterior drainage. (a) T2-weighted magnetic resonance (MR) image shows multiple flow voids in the posterior cavernous sinus (arrows). (b) Left external carotid arteriogram shows a cavernous sinus dural AVF with posterior drainage into the inferior and superior petrosal sinuses (arrows). (c) Follow-up MR image shows resolution of the flow voids.
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Figure 5b. Spontaneous regression of a cavernous sinus dural AVF with posterior drainage. (a) T2-weighted magnetic resonance (MR) image shows multiple flow voids in the posterior cavernous sinus (arrows). (b) Left external carotid arteriogram shows a cavernous sinus dural AVF with posterior drainage into the inferior and superior petrosal sinuses (arrows). (c) Follow-up MR image shows resolution of the flow voids.
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Figure 5c. Spontaneous regression of a cavernous sinus dural AVF with posterior drainage. (a) T2-weighted magnetic resonance (MR) image shows multiple flow voids in the posterior cavernous sinus (arrows). (b) Left external carotid arteriogram shows a cavernous sinus dural AVF with posterior drainage into the inferior and superior petrosal sinuses (arrows). (c) Follow-up MR image shows resolution of the flow voids.
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Figure 6a. TVE via an occluded inferior petrosal sinus with changes in the drainage pattern of a cavernous sinus dural AVF. (a) Left external carotid angiogram shows a cavernous sinus dural AVF draining mainly into the inferior petrosal sinus (arrows) and pterygopharyngeal plexus (arrowheads). (b) Follow-up angiogram obtained 3 months later shows significant changes in the drainage pattern. The inferior petrosal sinus is occluded, and the dural AVF now drains into the superior ophthalmic vein (arrows) and the superficial middle cerebral vein (arrowheads). Although the patient’s symptoms (mild chemosis, proptosis, diplopia) were unchanged during follow-up, occlusion of the dural AVF was indicated because of the change into a dangerous drainage pattern. (c) Superselective venogram shows the tip of a microcatheter that has been introduced into the cavernous sinus outlets to the superficial middle cerebral vein. (d) Superselective venogram shows that the tip of the microcatheter has been introduced into the outlets to the superior ophthalmic vein. Note that the microcatheter has been advanced through the occluded sinus. (e) Left common carotid angiogram obtained after TVE shows complete occlusion of the dural AVF. Before placement of the coils, it is important to determine whether a microcatheter can be introduced into all outlets of the cavernous sinus.
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Figure 6b. TVE via an occluded inferior petrosal sinus with changes in the drainage pattern of a cavernous sinus dural AVF. (a) Left external carotid angiogram shows a cavernous sinus dural AVF draining mainly into the inferior petrosal sinus (arrows) and pterygopharyngeal plexus (arrowheads). (b) Follow-up angiogram obtained 3 months later shows significant changes in the drainage pattern. The inferior petrosal sinus is occluded, and the dural AVF now drains into the superior ophthalmic vein (arrows) and the superficial middle cerebral vein (arrowheads). Although the patient’s symptoms (mild chemosis, proptosis, diplopia) were unchanged during follow-up, occlusion of the dural AVF was indicated because of the change into a dangerous drainage pattern. (c) Superselective venogram shows the tip of a microcatheter that has been introduced into the cavernous sinus outlets to the superficial middle cerebral vein. (d) Superselective venogram shows that the tip of the microcatheter has been introduced into the outlets to the superior ophthalmic vein. Note that the microcatheter has been advanced through the occluded sinus. (e) Left common carotid angiogram obtained after TVE shows complete occlusion of the dural AVF. Before placement of the coils, it is important to determine whether a microcatheter can be introduced into all outlets of the cavernous sinus.
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Figure 6c. TVE via an occluded inferior petrosal sinus with changes in the drainage pattern of a cavernous sinus dural AVF. (a) Left external carotid angiogram shows a cavernous sinus dural AVF draining mainly into the inferior petrosal sinus (arrows) and pterygopharyngeal plexus (arrowheads). (b) Follow-up angiogram obtained 3 months later shows significant changes in the drainage pattern. The inferior petrosal sinus is occluded, and the dural AVF now drains into the superior ophthalmic vein (arrows) and the superficial middle cerebral vein (arrowheads). Although the patient’s symptoms (mild chemosis, proptosis, diplopia) were unchanged during follow-up, occlusion of the dural AVF was indicated because of the change into a dangerous drainage pattern. (c) Superselective venogram shows the tip of a microcatheter that has been introduced into the cavernous sinus outlets to the superficial middle cerebral vein. (d) Superselective venogram shows that the tip of the microcatheter has been introduced into the outlets to the superior ophthalmic vein. Note that the microcatheter has been advanced through the occluded sinus. (e) Left common carotid angiogram obtained after TVE shows complete occlusion of the dural AVF. Before placement of the coils, it is important to determine whether a microcatheter can be introduced into all outlets of the cavernous sinus.
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Figure 6d. TVE via an occluded inferior petrosal sinus with changes in the drainage pattern of a cavernous sinus dural AVF. (a) Left external carotid angiogram shows a cavernous sinus dural AVF draining mainly into the inferior petrosal sinus (arrows) and pterygopharyngeal plexus (arrowheads). (b) Follow-up angiogram obtained 3 months later shows significant changes in the drainage pattern. The inferior petrosal sinus is occluded, and the dural AVF now drains into the superior ophthalmic vein (arrows) and the superficial middle cerebral vein (arrowheads). Although the patient’s symptoms (mild chemosis, proptosis, diplopia) were unchanged during follow-up, occlusion of the dural AVF was indicated because of the change into a dangerous drainage pattern. (c) Superselective venogram shows the tip of a microcatheter that has been introduced into the cavernous sinus outlets to the superficial middle cerebral vein. (d) Superselective venogram shows that the tip of the microcatheter has been introduced into the outlets to the superior ophthalmic vein. Note that the microcatheter has been advanced through the occluded sinus. (e) Left common carotid angiogram obtained after TVE shows complete occlusion of the dural AVF. Before placement of the coils, it is important to determine whether a microcatheter can be introduced into all outlets of the cavernous sinus.
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Figure 6e. TVE via an occluded inferior petrosal sinus with changes in the drainage pattern of a cavernous sinus dural AVF. (a) Left external carotid angiogram shows a cavernous sinus dural AVF draining mainly into the inferior petrosal sinus (arrows) and pterygopharyngeal plexus (arrowheads). (b) Follow-up angiogram obtained 3 months later shows significant changes in the drainage pattern. The inferior petrosal sinus is occluded, and the dural AVF now drains into the superior ophthalmic vein (arrows) and the superficial middle cerebral vein (arrowheads). Although the patient’s symptoms (mild chemosis, proptosis, diplopia) were unchanged during follow-up, occlusion of the dural AVF was indicated because of the change into a dangerous drainage pattern. (c) Superselective venogram shows the tip of a microcatheter that has been introduced into the cavernous sinus outlets to the superficial middle cerebral vein. (d) Superselective venogram shows that the tip of the microcatheter has been introduced into the outlets to the superior ophthalmic vein. Note that the microcatheter has been advanced through the occluded sinus. (e) Left common carotid angiogram obtained after TVE shows complete occlusion of the dural AVF. Before placement of the coils, it is important to determine whether a microcatheter can be introduced into all outlets of the cavernous sinus.
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TVE is the first-line curative therapy in cavernous sinus dural AVF.
Techniques
Transfemoral Inferior Petrosal Sinus Route.—
Although the inferior petrosal sinus often reveals complete occlusion, in most cases microcatheters can be introduced through the occluded sinus into the cavernous sinus (Fig 6) (38). Vessel perforation with the guide wire and microcatheter during navigation through the occluded sinus is a rare but serious complication. Knowledge of the course of the inferior petrosal sinus and gentle and careful manipulation of the catheter–guide wire under "road map" guidance are important.
Anterior Approach.—
The second most common approach involves the transfemoral facial venous or superficial temporal venous access route (Fig 7) and the surgical superior ophthalmic venous access route (27,39–42). With the anterior approach, there is less risk of intracranial vessel perforation. Disadvantages of this approach include (a) the poor maneuverability of the catheter–guide wire due to the tortuous access route of the transfemoral approach and (b) the risk of superior ophthalmic vein injury.
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Figure 7a. TVE with an anterior approach via the superficial temporal vein. (a) Left carotid angiogram shows a cavernous sinus dural AVF draining into the superior ophthalmic vein, the facial vein (arrowheads), and the superficial temporal vein (arrows). Note the occlusion of the inferior petrosal sinus. (b) Superselective venogram shows a microcatheter that has been advanced through the superficial temporal and superior ophthalmic veins into the posterior compartment of the cavernous sinus. The dural AVF was completely obliterated with subsequent coil embolization.
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Figure 7b. TVE with an anterior approach via the superficial temporal vein. (a) Left carotid angiogram shows a cavernous sinus dural AVF draining into the superior ophthalmic vein, the facial vein (arrowheads), and the superficial temporal vein (arrows). Note the occlusion of the inferior petrosal sinus. (b) Superselective venogram shows a microcatheter that has been advanced through the superficial temporal and superior ophthalmic veins into the posterior compartment of the cavernous sinus. The dural AVF was completely obliterated with subsequent coil embolization.
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Other Approaches.—
Although the majority of cases of cavernous sinus dural AVF can be treated with the trans–inferior petrosal sinus approach or anterior approach, there are other potential approaches, such as the transsuperior petrosal sinus approach, the transcontralateral cavernous sinus approach, the transbasilar plexus approach, and the surgical cortical venous approach (43–45). These less common approaches should be attempted when the two more common approaches are impossible or have failed.
Coil Embolization.—
Outlets of the cavernous sinus to dangerous venous drainage systems (cortical reflux, deep venous drainage, anterior drainage) should be occluded immediately. Incomplete or inadequate embolization of dangerous venous outlets could increase venous hypertension. Before the coils are placed, it is important to determine whether a microcatheter can be introduced into all outlets of the cavernous sinus (Fig 6). Furthermore, because the pressure in the remaining drainage veins will increase during embolization, the procedure should be kept as short as possible (46). In this regard, the anterior approach is advantageous in that it allows embolization of the posterior part of the cavernous sinus first. In most cases, feeding artery shunts occur mainly in the posterior compartment of the cavernous sinus; therefore, embolization of this compartment first can reduce shunt flow and the risk of increasing venous pressure. After the occlusion of dangerous and symptomatic venous drainage systems, the cavernous sinus is embolized by placing coils mainly in the shunting portion. Dense packing of the cavernous sinus with coils should be avoided because of the risk of cranial nerve deficits due to compression of the cranial nerves by the coils (26,46).
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Transverse-Sigmoid Sinus Dural AVFs
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Although their most common symptoms are benign (pulsatile tinnitus and headache), transverse-sigmoid sinus dural AVFs are more frequently associated with hemorrhagic and nonhemorrhagic aggressive neurologic symptoms than are cavernous sinus dural AVFs (Table 1) (3,7,11). The risk of aggressive neurologic symptoms correlates well with the venous drainage pattern of transverse-sigmoid sinus dural AVFs. The classification system devised by Lalwani et al (11) is useful for predicting risk and determining the best treatment strategy. Grade 1 transverse-sigmoid sinus dural AVFs are characterized by antegrade sinus drainage without venous restriction or cortical venous reflux; Grade 2, by antegrade and retrograde sinus drainage with or without cortical venous reflux; Grade 3, by retrograde sinus drainage with cortical venous reflux; and Grade 4, by cortical venous reflux only (Fig 8). Spontaneous regression of these AVFs is relatively rare (approximately 5% of cases) and usually occurs following hemorrhagic events (47).
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Figure 8. Drawings illustrate a classification scheme for transverse-sigmoid sinus dural AVFs that is based on venous drainage patterns: Grade 1, antegrade sinus drainage without venous restriction or cortical venous reflux; Grade 2, antegrade and retrograde sinus drainage with or without cortical venous reflux; Grade 3, retrograde sinus drainage with cortical venous reflux; and Grade 4, cortical venous reflux only. (Reprinted, with permission, from reference 11.)
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All transverse-sigmoid sinus dural AVFs are considered to require treatment because of the low rate of spontaneous regression without symptomatic events and the relatively high rate of aggressive symptoms. Treatment options include irradiation, surgical isolation or resection, TAE with particles or cyanoacrylate, and TVE. Recent studies of stereotactic radiation therapy for transverse-sigmoid sinus dural AVFs showed a relatively high occlusion rate of the AVF (approximately 60% of cases) several months after treatment without significant complications (17,18). Although TVE showed higher occlusion rates (80%–100% of cases), this procedure requires sacrifice of sinus flow and may cause venous infarction if the sinus contributes to the drainage of normal cerebral tissue (25,48,49). The rate of permanent complications in TVE is approximately 4% (48,49). The efficacy, potential risk, and difficulty of the treatment options for transverse-sigmoid sinus dural AVFs are described in Table 5, and a summary of strategies according to lesion grade is shown in Table 6. In the treatment of Grade 2 lesions, occlusion of the normal cortical venous drainage system should be avoided. When there is a high risk of normal cortical venous drainage sacrifice at TVE, other treatments such as radiation therapy should be applied. Surgical isolation of the sinus with preservation of normal cortical venous drainage may also be performed but is more invasive. Grade 3 lesions can be treated with TVE, during which time the affected sinus and retrograde cortical drainage outlet should be tightly packed with coils. Loose packing might cause recanalization, resulting in delayed hemorrhagic infarction after embolization (Fig 9). Although endovascular stent placement can restore antegrade sinus flow and close shunts within the sinus wall, only a few successful cases have been reported (31,32); therefore, further investigation of the effectiveness of stent placement in the treatment of dural AVFs is necessary. Grade 4 lesions are the most difficult type of dural AVF to treat. The standard techniques combine endovascular and neurosurgical elements (eg, TVE combined with a surgical approach) (50–52). In patients in poor general condition, other techniques (eg, TVE combined with other approaches, TAE with n-butyl-2-cyanoacrylate) may be used; however, they require more skill (28).
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Figure 9a. Recanalization of a grade 3 transverse-sigmoid sinus dural AVF after TVE. (a) Early arterial phase left common carotid angiogram shows a Grade 3 transverse-sigmoid sinus dural AVF. (b) Late arterial phase left common carotid angiogram shows that the left sigmoid sinus is occluded (arrow) and the dural AVF drains mainly into cortical veins and the posterior condylar vein (arrowheads). (c) Superselective venogram shows a microcatheter that has been advanced via the posterior condylar vein (arrowheads) into the affected sinus. (d) Left common carotid angiogram obtained after TVE shows disappearance of the AVF. (e) CT scan obtained 2 months after TVE shows a massive hemorrhage in the left temporal lobe. (f) Left common carotid angiogram shows recanalization of the dural AVF at the retrograde cortical drainage outlet (arrows).
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Figure 9b. Recanalization of a grade 3 transverse-sigmoid sinus dural AVF after TVE. (a) Early arterial phase left common carotid angiogram shows a Grade 3 transverse-sigmoid sinus dural AVF. (b) Late arterial phase left common carotid angiogram shows that the left sigmoid sinus is occluded (arrow) and the dural AVF drains mainly into cortical veins and the posterior condylar vein (arrowheads). (c) Superselective venogram shows a microcatheter that has been advanced via the posterior condylar vein (arrowheads) into the affected sinus. (d) Left common carotid angiogram obtained after TVE shows disappearance of the AVF. (e) CT scan obtained 2 months after TVE shows a massive hemorrhage in the left temporal lobe. (f) Left common carotid angiogram shows recanalization of the dural AVF at the retrograde cortical drainage outlet (arrows).
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Figure 9c. Recanalization of a grade 3 transverse-sigmoid sinus dural AVF after TVE. (a) Early arterial phase left common carotid angiogram shows a Grade 3 transverse-sigmoid sinus dural AVF. (b) Late arterial phase left common carotid angiogram shows that the left sigmoid sinus is occluded (arrow) and the dural AVF drains mainly into cortical veins and the posterior condylar vein (arrowheads). (c) Superselective venogram shows a microcatheter that has been advanced via the posterior condylar vein (arrowheads) into the affected sinus. (d) Left common carotid angiogram obtained after TVE shows disappearance of the AVF. (e) CT scan obtained 2 months after TVE shows a massive hemorrhage in the left temporal lobe. (f) Left common carotid angiogram shows recanalization of the dural AVF at the retrograde cortical drainage outlet (arrows).
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Figure 9d. Recanalization of a grade 3 transverse-sigmoid sinus dural AVF after TVE. (a) Early arterial phase left common carotid angiogram shows a Grade 3 transverse-sigmoid sinus dural AVF. (b) Late arterial phase left common carotid angiogram shows that the left sigmoid sinus is occluded (arrow) and the dural AVF drains mainly into cortical veins and the posterior condylar vein (arrowheads). (c) Superselective venogram shows a microcatheter that has been advanced via the posterior condylar vein (arrowheads) into the affected sinus. (d) Left common carotid angiogram obtained after TVE shows disappearance of the AVF. (e) CT scan obtained 2 months after TVE shows a massive hemorrhage in the left temporal lobe. (f) Left common carotid angiogram shows recanalization of the dural AVF at the retrograde cortical drainage outlet (arrows).
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Figure 9e. Recanalization of a grade 3 transverse-sigmoid sinus dural AVF after TVE. (a) Early arterial phase left common carotid angiogram shows a Grade 3 transverse-sigmoid sinus dural AVF. (b) Late arterial phase left common carotid angiogram shows that the left sigmoid sinus is occluded (arrow) and the dural AVF drains mainly into cortical veins and the posterior condylar vein (arrowheads). (c) Superselective venogram shows a microcatheter that has been advanced via the posterior condylar vein (arrowheads) into the affected sinus. (d) Left common carotid angiogram obtained after TVE shows disappearance of the AVF. (e) CT scan obtained 2 months after TVE shows a massive hemorrhage in the left temporal lobe. (f) Left common carotid angiogram shows recanalization of the dural AVF at the retrograde cortical drainage outlet (arrows).
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Figure 9f. Recanalization of a grade 3 transverse-sigmoid sinus dural AVF after TVE. (a) Early arterial phase left common carotid angiogram shows a Grade 3 transverse-sigmoid sinus dural AVF. (b) Late arterial phase left common carotid angiogram shows that the left sigmoid sinus is occluded (arrow) and the dural AVF drains mainly into cortical veins and the posterior condylar vein (arrowheads). (c) Superselective venogram shows a microcatheter that has been advanced via the posterior condylar vein (arrowheads) into the affected sinus. (d) Left common carotid angiogram obtained after TVE shows disappearance of the AVF. (e) CT scan obtained 2 months after TVE shows a massive hemorrhage in the left temporal lobe. (f) Left common carotid angiogram shows recanalization of the dural AVF at the retrograde cortical drainage outlet (arrows).
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Tentorial Dural AVFs
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Because tentorial dural AVFs drain only via the leptomeningeal vein, they carry a high risk of aggressive neurologic symptoms (Table 1). The reported occurrence of intracranial hemorrhage ranges from 60% to 74%; in some cases, this hemorrhage consists of fatal bleeding in the posterior fossa (3).
Treatment options include irradiation, surgical interruption of the draining vein with or without resection, TAE with cyanoacrylate, and TVE (15,18,21,29,30,53–58). The efficacy, potential risk, and difficulty of these options are described in Table 7. Tentorial dural AVFs drain through the retrograde leptomeningeal-cortical venous drainage system only (Cognard types III and IV, Borden type III), resulting in a high risk of hemorrhagic or nonhemorrhagic aggressive symptoms (19% and 10% of cases per year, respectively). Complete cure of such AVFs requires aggressive treatment. Interventional and surgical procedures are both used to disconnect the venous drainage system; however, because of the deep-seated location of such lesions, the difficult access route, and the need for n-butyl-2-cyanoacrylate (Fig 10), these techniques require a high level of skill (53–55). Treatment selection depends on the skill of the neurosurgeon and interventional radiologist and on lesion accessibility. Stereotactic radiosurgery should be considered an option, especially in older patients or in those in poor general condition (Fig 11) (15,18,21).
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Figure 10a. Type IV tentorial dural AVF with intracranial hemorrhage. (a) Unenhanced CT scan shows intracranial hemorrhage in the left occipital lobe and the lateral ventricle. (b) Left external carotid angiogram shows a tentorial dural AVF (arrowheads) with leptomeningeal-cortical venous drainage and venous ectasia (arrow). (c) Digital subtraction angiogram obtained during the injection of diluted n-butyl-2 cyanoacrylate demonstrates the tip of a microcatheter (arrow). (d) Left common carotid angiogram obtained after TAE shows complete obliteration of the AVF.
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Figure 10b. Type IV tentorial dural AVF with intracranial hemorrhage. (a) Unenhanced CT scan shows intracranial hemorrhage in the left occipital lobe and the lateral ventricle. (b) Left external carotid angiogram shows a tentorial dural AVF (arrowheads) with leptomeningeal-cortical venous drainage and venous ectasia (arrow). (c) Digital subtraction angiogram obtained during the injection of diluted n-butyl-2 cyanoacrylate demonstrates the tip of a microcatheter (arrow). (d) Left common carotid angiogram obtained after TAE shows complete obliteration of the AVF.
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Figure 10c. Type IV tentorial dural AVF with intracranial hemorrhage. (a) Unenhanced CT scan shows intracranial hemorrhage in the left occipital lobe and the lateral ventricle. (b) Left external carotid angiogram shows a tentorial dural AVF (arrowheads) with leptomeningeal-cortical venous drainage and venous ectasia (arrow). (c) Digital subtraction angiogram obtained during the injection of diluted n-butyl-2 cyanoacrylate demonstrates the tip of a microcatheter (arrow). (d) Left common carotid angiogram obtained after TAE shows complete obliteration of the AVF.
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Figure 10d. Type IV tentorial dural AVF with intracranial hemorrhage. (a) Unenhanced CT scan shows intracranial hemorrhage in the left occipital lobe and the lateral ventricle. (b) Left external carotid angiogram shows a tentorial dural AVF (arrowheads) with leptomeningeal-cortical venous drainage and venous ectasia (arrow). (c) Digital subtraction angiogram obtained during the injection of diluted n-butyl-2 cyanoacrylate demonstrates the tip of a microcatheter (arrow). (d) Left common carotid angiogram obtained after TAE shows complete obliteration of the AVF.
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Abstract
LEARNING OBJECTIVES
