Onyx embolization of anterior condylar confluence dural arteriovenous fistula

Dural arteriovenous fistulas of the anterior condylar confluence involving the anterior condylar vein within the hypoglossal canal: Two case reports

Background

Dural arteriovenous fistulas (DAVFs) of the anterior condylar confluence (ACC) are rare vascular lesions at the skull base, often characterized by complex venous anatomy and variable clinical presentations. Their symptoms may overlap with those of cavernous sinus (CS) DAVFs, leading to potential misdiagnosis. Advanced imaging techniques and individualized treatment approaches are essential for accurate diagnosis and effective management.

Case Description

We present two cases of ACC DAVFs successfully treated with transvenous embolization (TVE). The first case involved a patient with hypoglossal nerve palsy and non-specific headache. The second case presented with cranial nerve III palsy, proptosis, and diplopia due to retrograde venous drainage into the CS, along with hypoglossal nerve symptoms, including tongue stiffness and difficulty speaking. Both patients experienced complete resolution of symptoms following treatment.

Conclusion

ACC DAVFs are challenging to diagnose and treat due to their anatomical complexity and diverse presentations. These cases highlight the efficacy and safety of TVE as the preferred treatment, underscoring the critical role of advanced imaging and individualized management in achieving favorable outcomes.

Posterior condylar canal dural arteriovenous fistula: anatomical, symptomatological, and therapeutic considerations in comparison with hypoglossal canal dural arteriovenous fistula

BACKGROUND

Posterior condylar canal dural arteriovenous fistulas (dAVFs) are extremely rare.

METHODS

We report a case series and literature review of posterior condylar canal dAVFs and discuss similarities and differences between posterior condylar and hypoglossal canal dAVFs with respect to the related vascular anatomy, angioarchitecture of the fistula, presentation, and treatment.

RESULTS

Four cases of posterior condylar canal dAVF were identified at our institutions and six cases were identified in the literature. Posterior condylar canal dAVFs were predominantly frequent in relatively young women. All patients presented with pulsatile tinnitus. There was no history of hemorrhage as there was no cortical venous reflux. This is different from hypoglossal canal dAVFs which can present with myelopathy or hemorrhage from cortical venous reflux. Transvenous embolization was safe and eliminated the symptoms. Palliative transarterial embolization can be an option to mitigate the symptoms, although there is a potential risk of cranial nerve palsy or lateral medullary stroke.

CONCLUSIONS

Posterior condylar canal dAVFs are generally benign lesions. However, intolerable tinnitus may require intervention. Transvenous embolization is effective and safe.

The combined transarterial and transvenous onyx embolization of dural arteriovenous fistula of hypoglossal canal via the external jugular vein and facial vein: A case report

Dural arteriovenous fistulas of the hypoglossal canal (HCDAVFs) involving the anterior condylar confluence (ACC) and anterior condylar vein (ACV) are infrequent. Although transvenous embolization through the internal jugular vein (IJV) is the preferred treatment option for type I and II fistulas, it can be difficult if the IJV is unavailable. Here we report a rare case of HCDAVF in which the most common transvenous embolization access via IJV was not available. The patient underwent transarterial and transvenous onyx embolization. Transarterial embolization (TAE) aimed at controlling the arterial inflow and subsequently TVE was performed via the external jugular vein (EJV), the facial vein, the ophthalmic vein, the cavernous sinus, ACC, and ultimately to the fistula pouch. Complete obliteration of the HCDAVF was achieved without complications. We suggest that transvenous embolization (TVE) via the EJV and the facial vein can be effective in cases where trans-IJV is not possible.

Endovascular Management of Intracranial Dural AVFs: Transvenous Approach

In this third review article on the endovascular management of intracranial dural AVFs, we discuss transvenous embolization approaches. Transvenous embolization is increasingly popular and now the first-line approach for ventral dural AVFs involving the cavernous sinus and hypoglossal canal. In addition, transvenous embolization is increasingly used in lateral epidural dural AVFs in high-risk locations such as the petrous and ethmoid regions. The advantage of transvenous embolization in these locations is the ability to retrogradely embolize the draining vein and fistula while reducing the risk of ischemic cranial neuropathy or brain parenchymal infarction commonly feared from a transarterial approach. By means of coils ± ethylene-vinyl alcohol copolymer, transvenous embolization can achieve angiographic cure rates of 80%-90% in ventral locations. Potential complications include transient cranial neuropathy, neurologic deterioration due to venous outflow obstruction, and perforation while navigating pial veins. Transvenous embolization should be considered when dural AVFs arise in proximity to the vasa nervosum or extracranial-intracranial anastomoses.

Resolution of hypoglossal nerve palsy after coil embolization of an anterior condylar confluence fistula

A 69-year-old female presented with 2-year history of slurred speech, left-sided pulsatile tinnitus, and left-sided hypoglossal nerve palsy. Cerebral angiography demonstrated a left anterior condylar confluence fistula. She was treated with a transvenous coil embolization of the left condylar fistula pocket.

Endovascular treatment strategy, technique, and outcomes for dural arteriovenous fistulas of the marginal sinus region

BACKGROUND

Dural arteriovenous fistulas (AVF) of the foramen magnum region (FMR) are technically challenging lesions to treat. Transvenous (TV), transarterial (TA), and surgical approaches have been described, but the optimum treatment strategy is not defined.

OBJECTIVE

To report treatment strategies and outcomes for FMR-AVF at a single, high-volume referral center.

METHODS

A retrospective review from January 2010 to August 2020 identified patients with FMR-AVF at a single referral center. Angiographic features, treatment (observation, endovascular, surgical), and follow-up of angiographic and clinical results were recorded. The technical aspects of TV embolization are then presented in detail.

RESULTS

29 FMR-AVF were identified in 28 patients. Of these, 24/29 (82.8%) were treated and 5/29 (17.2%) were observed. Treatment was endovascular in 21/24 (87.5%), combined (endovascular+surgical) in 2/24 (8.3%), and surgical in 1/24 (4.2%). Endovascular treatments were 76.2% TV, 14.3% TA, and 9.5% combined TV/TA. Sufficient follow-up data were available for 20/28 (71.4%) with mean follow-up of 16.8 months. No AVF recurrence was seen for TA/TV, combined endovascular/surgical, or surgical groups, and there was one recurrence (7.1%) in the TV group. Symptomatic improvement was seen in all groups: TV (71.4% complete, 28.6% partial), TA (66.7% complete, 33.3% no follow-up), TV+TA (100% partial), endovascular/surgical (100% complete), and surgical (100% partial). Minor non-neurologic complications included 1/14 (7.1%) in the TV group and 1/3 (33.3%) in the TA/TV group.

CONCLUSION

Endovascular treatment is safe and effective for most FMR-AVF. TV embolization has a high cure rate with few complications.

Dural Arteriovenous Fistulas of the Foramen Magnum Region: Clinical Features and Angioarchitectural Phenotypes

BACKGROUND AND PURPOSE

AVFs of the foramen magnum region, including fistulas of the marginal sinus and condylar veins, have complex arterial supply, venous drainage, symptoms, and risk features that are not well-defined. The purpose of this study was to present the angioarchitectural and clinical phenotypes of a foramen magnum region AVF from a large, single-center experience.

MATERIALS AND METHODS

We retrospectively reviewed cases from a 10-year neurointerventional data base. Arterial and venous angioarchitectural features and clinical presentation were extracted from the medical record. Venous drainage patterns were stratified into 4 groups as follows: type 1 = unrestricted sinus drainage, type 2 = sinus reflux (including the inferior petrosal sinus), type 3 = reflux involving sinuses and cortical veins, and type 4 = restricted cortical vein outflow or perimedullary congestion.

RESULTS

Twenty-eight patients (mean age, 57.9 years; 57.1% men) had 29 foramen magnum region AVFs. There were 11 (37.9%) type 1, nine (31.0%) type 2, six (20.7%) type 3, and 3 (10.3%) type 4 fistulas. Pulsatile tinnitus was the most frequent symptom (82.1%), followed by orbital symptoms (31.0%), subarachnoid hemorrhage (13.8%), cranial nerve XII palsy (10.3%), and other cranial nerve palsy (6.9%). The most frequent arterial supply was the ipsilateral ascending pharyngeal artery (93.1% ipsilateral, 55.5% contralateral), vertebral artery (89.7%), occipital artery (65.5%), and internal carotid artery branches (48.3%).

CONCLUSIONS

We present the largest case series of foramen magnum region AVFs to date and show that clinical features relate to angioarchitecture. Orbital symptoms are frequent when sinus reflux is present. Hemorrhage was only observed in type 3 and 4 fistulas.

Foramen Magnum Dural Arteriovenous Fistulas: Clinical Presentations and Treatment Outcomes, A Case-Series of 12 Patients

BACKGROUND

Dural arteriovenous fistulas (DAVFs) are usually seen in relation to the venous sinuses, but in certain rare instances fistulas may not drain directly into the venous sinuses but rather drain into the cortical veins. This rare form of DAVF may present with either intracranial hemorrhage or myelopathy. The mode of clinical presentation is influenced by the venous outflow into either intracranial drainage or caudally intraspinal drainage.

OBJECTIVE

To evaluate the clinical presentations, angioarchitectural characteristics, and treatment of 12 patients who presented with DAVF in the region of the foramen magnum.

METHODS

In this case series we reviewed clinical charts, radiological images, and operative notes of 12 patients who were diagnosed of foramen magnum DAVF from December 1993 until April 2017. The angiographic studies were analyzed for feeding arteries, the location of the shunt, the venous drainage patterns, and the presence of venous side aneurysms.

RESULTS

Twelve patients were angiographically confirmed with foramen magnum DAVFs. They included 11 males and 1 female (M:F = 11:1). Mean age of 55.6 yr ranging between 42 yr and 71 yr of age. Eight patients presented with progressive myelopathy, 3 patients with posterior fossa intracranial hemorrhage, and 1 patient presented with lower cranial nerve IX and XII palsies due to mass effect.

CONCLUSION

A dural arteriovenous shunt, which may be located in the region of the foramen magnum, should be suspected in those cases of subarachnoid hemorrhage in the posterior fossa or progressive myelopathy mimicking spinal DAVF.

Transvenous Embolization of Dural Arteriovenous Fistulas of the Hypoglossal Canal: Report of Three Cases and Review of the Literature

In this article, we report three cases of dural arteriovenous fistulas of the hypoglossal canal treated via transvenous approach. We also perform a review of the literature on the endovascular management of this type of lesions with particular attention to the dangerous extracranial-intracranial anastomoses that can occur at this level.

An analysis of the anatomic route of the hypoglossal nerve within the hypoglossal canal using dynamic computed tomography angiography in patients with anterior condylar arteriovenous fistulas

OBJECTIVE

The venous outlet of anterior condylar arteriovenous fistulas (AC-AVFs) often empties into the anterior condylar vein (ACV). Hypoglossal nerve palsy is one of the major complications after transvenous embolization (TVE) for the AC-AVF within the hypoglossal canal. However, no studies have investigated the route of the hypoglossal nerve within the hypoglossal canal in AC-AVF. The aim of the current study is to retrospectively verify the anatomical route of the hypoglossal nerve within its canal using dynamic computed tomography angiography (CTA) in order to facilitate the safe TVE for AC-AVF.

PATIENTS AND METHODS

We included five patients with AC-AVF from 2011 to 2017. Dynamic CTA was performed on all patients. When the ACV was well-visualized by dynamic CTA, the hypoglossal nerve could be recognized as a less-intense structure within the surrounding enhanced vasculatures and the nerve route within the canal was analyzed. We also analyzed the location of the fistulas by digital subtraction angiography and cone-beam computed tomography.

RESULTS

In all five patients, the filling defect of the hypoglossal nerve ran through the most caudal portion of the hypoglossal canal. The fistulous pouches were located in the hypoglossal canal in three cases, and in the jugular tubercle venous complex in two cases. In all three cases with AC-AVF in the hypoglossal canal, the fistulous pouches were located in the superior wall of the hypoglossal canal, which means superior to the ACV. We performed TVE in four patients and none developed post-therapeutic hypoglossal nerve palsy.

CONCLUSION

In the current study, dynamic CTA is useful for detecting the hypoglossal nerve within the hypoglossal canal. The hypoglossal nerve usually ran the bottom of its canal and the fistulous pouches were usually located at the superior aspect of the canal opposite side to the hypoglossal nerve. Accordingly, the selective embolization within the fistulous pouch located in the superior aspect of the ACV including jugular tubercle venous complex can reduce the risk of hypoglossal nerve palsy.

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.

Dural arteriovenous fistula of the lateral foramen magnum region: A review

The lateral foramen magnum region is defined as the bilateral occipital area that runs laterally up to the jugular foramen. The critical vasculatures of this region are not completely understood. Dural arteriovenous fistulas that occur in this region are rare and difficult to treat. Therefore, we searched PubMed to identify all relevant previously published English language articles about lateral foramen magnum dural arteriovenous fistulas, and we performed a review of this literature to increase understanding about these fistulas. Four types of dural arteriovenous fistulas occur in the lateral foramen magnum region. These include anterior condylar confluence and anterior condylar vein dural arteriovenous fistulas, posterior condylar canal dural arteriovenous fistulas, marginal sinus dural arteriovenous fistulas, and jugular foramen dural arteriovenous fistulas. These dural arteriovenous fistulas share similar angioarchitectures and clinical characteristics. The clinical presentations of lateral foramen magnum dural arteriovenous fistulas include pulsatile tinnitus, intracranial hemorrhage, myelopathy, orbital symptoms, and cranial nerve palsy. Currently, head computed tomography, computed tomography angiography, magnetic resonance imaging, magnetic resonance angiography and digital subtraction angiography (DSA) are useful for diagnosing dural arteriovenous fistulas, and of these, DSA remains the "gold standard." Most lateral foramen magnum dural arteriovenous fistulas need to be treated due to their aggressive symptoms, and transvenous embolization presents the best options. During treatment, it is critical to accurately place the microcatheter into the fistula point, and intraoperative integrated computed tomography and DSA data are very helpful. Other treatments, such as transarterial embolization, microsurgery or conservative treatment, can also be chosen. After appropriate treatment, most patients with lateral foramen magnum dural arteriovenous fistulas achieve satisfactory outcomes.

Hypoglossal dural arteriovenous fistula: a rare cause of unilateral hypoglossal nerve palsy

Ms Y, a 57-year-old female presented with a 1-week history of tongue deviation. The history of the presenting complaint also included minor dysarthria, dysphagia for solids and liquids as well as a 2- to 3-month history of pulsatile tinnitus affecting the right ear. Examination of the cranial and peripheral nerves revealed a right hypoglossal nerve lower motor neurone palsy. MRI demonstrated a dural arteriovenous fistula (DAVF) in the region of the right hypoglossal canal. She underwent a cerebral angiogram, which confirmed a hypoglossal DAVF with predominant supply from the neuromeningeal branches of the right ascending pharyngeal artery. She has been able to cope with her symptoms and remains on active surveillance. Hypoglossal nerve palsy is uncommon, causes may be classified according to location. DAVFs are a rare cause of hypoglossal nerve palsy. DAVFs can be graded according to their pattern of venous drainage. This case illustrates the complex venous anatomy of the craniocervical junction, which enables postural-dependent drainage through the internal jugular and vertebral venous systems. This network of veins is encountered during interventional radiology procedures and neurosurgical skull base approaches.

Intraoperative cone-beam computed tomography contributes to avoiding hypoglossal nerve palsy during transvenous embolization for dural arteriovenous fistula of the anterior condylar confluence

BACKGROUND

Dural arteriovenous fistula of the anterior condylar confluence (ACC-DAVF) is a rare subtype of DAVFs that occurs around the hypoglossal canal. Transvenous embolization (TVE) with coils has been performed for most ACC-DAVFs with a high clinical cure rate. However, some reports call attention to hypoglossal nerve palsy associated with TVE due to coil mass compression of the hypoglossal nerve caused by coil deviation from the ACC to the anterior condylar vein (ACV). Herein, we report a case of ACC-DAVF in which an intraoperative cone-beam computed tomography (CT) contributed to avoiding hypoglossal nerve palsy.

CASE PRESENTATION

A 74-year-old man presented with left pulse-synchronous tinnitus. An angiography detected left ACC-DAVF mainly supplied by the left ascending pharyngeal artery and mainly drained through the ACV. The two fistulous points were medial side of the ACC and the venous pouch just cranial of the ACC. We performed TVE detecting the fistulous points by contralateral external carotid angiography (ECAG). The diseased venous pouch and ACC were packed with seven coils but a slight remnant of the DAVF was recognized. Because a cone-beam CT revealed that the coil mass was localized in the lateral lower clivus osseous without deviation to the hypoglossal canal, we finished TVE to avoid hypoglossal nerve palsy. Postoperatively, no complication was observed. No recurrence of symptoms or imaging findings were detected during a five-month follow-up period.

CONCLUSION

An intraoperative cone-beam CT contributed to avoiding hypoglossal nerve palsy by estimating the relationship between the coil mass and the hypoglossal canal during TVE of ACC-DAVF.

Retrograde leptomeningeal venous approach for dural arteriovenous fistulas at foramen magnum

A 72-year-old man presented with sudden right homonymous hemianopsia. Work-up imaging revealed a left occipital haematoma and an arteriovenous fistula supplied by the meningeal branches to the clivus from the left vertebral artery (VA) with a rostral venous reflux into cortical veins. A microcatheter was advanced through brainstem veins into the venous collector. A compliant balloon was placed in the left VA facing the origin of feeders. The balloon was inflated to protect the vertebrobasilar circulation from embolic migration. Onyx was injected by the transvenous catheter. Control angiogram revealed exclusion of the lesion. Informed consent was obtained from the patient.

Dural arteriovenous fistulas of the hypoglossal canal: systematic review on imaging anatomy, clinical findings, and endovascular management

Dural arteriovenous fistulas (DAVFs) of the hypoglossal canal (HCDAVFs) are rare and display a complex angiographic anatomy. Hitherto, they have been referred to as various entities (for example, “marginal sinus DAVFs”) solely described in case reports or small series. In this in-depth review of HCDAVF, the authors describe clinical and imaging findings, as well as treatment strategies and subsequent outcomes, based on a systematic literature review supplemented by their own cases (120 cases total). Further, the involved craniocervical venous anatomy with variable venous anastomoses is summarized. Hypoglossal canal DAVFs consist of a fistulous pouch involving the anterior condylar confluence and/or anterior condylar vein with a variable intraosseous component. Three major types of venous drainage are associated with distinct clinical patterns: Type 1, with anterograde drainage (62.5%), mostly presents with pulsatile tinnitus; Type 2, with retrograde drainage to the cavernous sinus and/or orbital veins (23.3%), is associated with ocular symptoms and may mimic cavernous sinus DAVF; and Type 3, with cortical and/or perimedullary drainage (14.2%), presents with either hemorrhage or cervical myelopathy. For Types 1 and 2 HCDAVF, transvenous embolization demonstrates high safety and efficacy (2.9% morbidity, 92.7% total occlusion). Understanding the complex venous anatomy is crucial for planning alternative approaches if standard transjugular access is impossible. Transarterial embolization or surgical disconnection (morbidity 13.3%–16.7%) should be reserved for Type 3 HCDAVFs or lesions with poor venous access. A conservative strategy could be appropriate in Type 1 HCDAVF for which spontaneous regression (5.8%) may be observed.

Endovascular treatment and computed imaging follow-up of 14 anterior condylar dural arteriovenous fistulas

We report our experience in treating the anterior condylar dural arteriovenous fistula (DAVF) and confirm the location of the coils in the follow-up images after successful endovascular treatment. We retrospectively reviewed the 14 patients with anterior condylar DAVF treated successfully in our institute. Twelve of them had CT or MR follow-up images. All the patients had intravascular coiling of the fistula. Seven of our patients had retrograde drainage to different sinuses. Three had ocular symptoms as a clinical manifestation. We treated nine patients with coils alone (eight transvenous, one transarterial), four with adjuvant transarterial treatment with particles or liquid embolic for minimal residual after coiling packing. One patient had failed onyx treatment and successful treatment by following transvenous packing. All patients had total obliteration of the DAVF fistula on immediate post-procedure angiogram or on the follow-up images and no evidence of recurrence clinically. The mean follow-up period was 34.2 months (standard deviation=39.8). Twelve patients had computed images (CT alone in four, MR alone in five, both CT and MR in three). These findings were analyzed by four certified neuroradiologists. We found 100% of the coils at the anterior condylar veins inside the hypoglossal canal, 54.2% at the lateral lower clivus, and only 14.2% at the anterior condylar confluence which is ventrolateral to the anterior orifice of the hypoglossal canal. Intravascular coiling is the treatment of choice in patients with anterior condylar DAVF. All the coils were found at the anterior condylar veins inside the hypoglossal canal after successful treatment.