Intraosseous cranial dural arteriovenous fistula treated with transvenous embolization

Transvenous embolization of noncavernous dural arteriovenous fistulas (dAVFs): A systematic review and meta-analysis

BACKGROUND

Intracranial dural arteriovenous fistulas (dAVFs) are abnormal connections between arteries and veins within the dura mater. Various treatment modalities, such as surgical ligation, endovascular intervention, and radiosurgery, aim to close the fistulous connection. Although transvenous embolization (TVE) is the preferred method for carotid-cavernous fistulas, its description and outcomes for noncavernous dAVFs vary. This has prompted a systematic review and meta-analysis to comprehensively assess the effectiveness of TVE in treating noncavernous dAVFs, addressing variations in outcomes and techniques.

METHODS

We searched PubMed and Embase, spanning from the earliest records to December 2022, to identify pertinent English-language articles detailing the utilization of TVE. We focused on specific procedural details, outcomes, and complications in patients older than 18 years. The data collected and analyzed comprised the sample size, number of fistulas, publication specifics, presenting symptoms, fistula grades, and pooled rates of embolizations, outcomes, follow-up information, and complications.

RESULTS

From a total of 565 screened articles, 15 retrospective articles encompassing 166 patients spanning across seven countries met the inclusion criteria. Their Newcastle-Ottawa scores ranged from 6 to 8. Intraprocedural complication rate was 10% (95% confidence interval [CI] = 5.9-17.1) and in-hospital postprocedural complication rate was 5.4% (95% CI = 2.8-10.6). Prevalence of in-hospital mortality was 5.5% (95% CI = 2.9-10.6). Complication rate during follow-up was 8.6% (95% CI = 4.7-15.7) with fistula rupture occurring in 5.5% (95% CI = 2.6-11.6) of patients. Complete obliteration rate at final angiographic follow-up was 94.9% (95% CI = 90.3-99.9). Symptoms improved in 95% (95% CI = 89.8-100) of patients at final follow-up.

CONCLUSION

To our knowledge, we present the first meta-analysis assessing obliteration rates, outcomes, and complications of TVE for dAVFs. Our analysis highlights the higher (>90%) complete obliteration rates. Large prospective multicenter studies are needed to better define the utility of TVE for noncavernous dAVFs.

An Intraosseous Pterygopalatine Fossa Dural Arteriovenous Fistula

Intraosseous dural arteriovenous fistulas (DAVFs) are distinct in that the fistula is located within the bone rather than the dura through which the dural vessels pass. It has been stated that only fistulas within marrow should be considered as intraosseous DAVFs rather than DAVFs with traditional angioarchitecture that erode into bone or are located within a bony foramen. The ambiguity in the definition may have contributed to the oversight and scarcity of relevant cases reported in the literature. Three- or four-dimensional digital subtraction angiography is useful for determining the location of the fistula and developing treatment plans. We present an intraosseous DAVF around the pterygopalatine fossa using a transvenous approach.

Transvenous embolization for an intraosseous clival arteriovenous fistula via a proper access route guiding a three-dimensional fusion image: illustrative case

BACKGROUND

Intraosseous clival arteriovenous fistulas (AVFs), in which the shunt drains extracranially from the posterior and anterior condylar veins rather than from the cavernous sinus (CS), are rare. Targeting embolization of an intraosseous clival AVF is challenging because of its complex venous and skull base anatomy; therefore, a therapeutic strategy based on detailed preoperative radiological findings is required to achieve a favorable outcome. Here, the authors report the successful targeted embolization of an intraosseous clival AVF using an ingenious access route.

OBSERVATIONS

A 74-year-old woman presented with left-sided visual impairment, oculomotor nerve palsy, and right facial pain. A fusion image of three-dimensional rotational angiography and cone-beam computed tomography revealed a left CS dural AVF and a right intraosseous clival AVF. The shunt flow of the clival AVF drained extracranially from the posterior and anterior condylar veins via the intraosseous venous route. Transvenous embolization was performed by devising suboccipital, posterior condylar, and intraosseous access routes. The symptoms resolved after the bilateral AVFs were treated.

LESSONS

Accurate diagnosis and proper transvenous access based on detailed intraosseous and craniocervical venous information obtained from advanced imaging modalities are key to resolving intraosseous clival AVF.

Classification and Management Considerations for Intraosseous Dural Arteriovenous Fistulae

BACKGROUND

Intraosseous dural arteriovenous fistulas (IODAVFs) are rare DAVFs that communicate with marrow. Given their infrequency, common nomenclature is nonexistent. Patients may present with benign symptoms, such as tinnitus, or venous hypertension symptoms including hemorrhage depending on the venous outflow pattern.

OBJECTIVE

To describe all available cases of IODAVF in the literature, in addition to our cases, to better define presentation, and treatment outcomes. To advance a classification system to develop common language for these lesions for clinicians and researchers.

METHODS

Neurointerventional procedure logs at 2 high-volume neurovascular centers were reviewed for all cases of IODAVFs, as was the English-based literature available in PubMed. The angioarchitecture, symptoms, management, and demographics were reviewed and summarized.

RESULTS

Four institutional cases were identified, 2 of which had shunting within the marrow (clival or petrous), with venous drainage toward the heart. One case involved the dorsum sella with drainage into the superior petrosal sinus with reflux into the anterior and posterior spinal venous plexuses, and one involved the left petroclival junction, resulting in communication with the cavernous sinus with retrograde drainage into the superior ophthalmic veins. Two patients were managed by observation, one was treated with radiosurgery and one with microsurgical skeletonization. Twenty additional cases from the literature are summarized.

CONCLUSION

IODAVFs of the cerebrocranial vasculature may present incidentally, with tinnitus, or with symptoms related to mass effect or venous hypertension. We propose a classification which accounts for drainage patterns. Further study is needed for these rare lesions.

Cone-beam CT-assisted microcatheter tip placement at the shunted pouch entry zone: A technical note for anterior condylar arteriovenous fistula

Accurate microcatheter placement for anterior condylar arteriovenous fistula (AVF) enables selective transvenous embolization (TVE) and helps to avoid hypoglossal nerve palsy. Anterior condylar AVF has a shunted pouch within the condylar vascular and osseous structures. Detailed anatomical comprehension of the shunted pouch is essential, in addition, we believe that it is important to have a strategy for where in the shunted pouch to start filling with coils. Specifically, we consider that it is important to structurally understand the more upstream location (arterial side) within the shunted pouch (called "shunted pouch entry zone"), guide the microcatheter there, and embolize from that site. Although several studies have discussed the usefulness of intraoperative cone-beam computed tomography (CBCT) for treating anterior condylar AVF, there are no studies which have mentioned the importance of microcatheter position before coil embolization in selective TVE as in this study. Intraoperative localization of the shunted pouch entry zone is often difficult. Herein, the authors report that cone-beam computed tomography (CBCT) can assist accurate microcatheter tip placement at the shunted pouch entry zone before staring embolization. This is the novel application of intraoperative CBCT to treat anterior condylar AVF successfully treated with precise and selective TVE.

Extracranial prevertebral venous network of the craniocervical junction: CT-digital subtraction venography analysis

PURPOSE

Although the craniocervical junction has a complex anatomical structure associated with clinical diseases, its ventral venous network has not been well studied. This study aimed to clarify the extracranial ventral venous structure at the craniocervical junction.

METHODS

Head computed tomography digital subtraction venography (CT-DSV) images of 273 patients (age 6 months to 93 years) taken at our department were retrospectively analyzed. We analyzed the frequency and anatomical features of the venous channels, as well as their upstream and downstream connections with the surrounding channels at the ventral craniocervical junction, from the level of the hypoglossal canal to the second cervical vertebra.

RESULTS

In 54% of the cases, the vein descended from the anterior condylar confluence, running medially along the basioccipital and fusing with its counterpart in the midline at the level of the atlanto-occipital membrane. Furthermore, 24% of this vein was connected caudally to the anterior external vertebral venous plexus. We also identified venous channels, either as a sole vein or venous plexus, on the tip of the odontoid process (10%), which has not been well described previously. The vein around the odontoid process was connected to several veins, including the aforementioned vein anterior to the condyle and the anterior internal vertebral venous plexus.

CONCLUSIONS

CT-DSV analysis revealed a detailed venous architecture ventral to the craniocervical junction. Venous structures identified in this study may be involved in diseases in this area.

Anterior cranial fossa osseous arteriovenous fistula of the crista galli with bone erosion: patient series

BACKGROUND

Although an anterior cranial fossa dural arteriovenous fistula (ACFdAVF) is thought to have a fistula on the dura near the olfactory groove, the detailed angioarchitecture remains unreported.

OBSERVATIONS

In case 1, a 65-year-old man was found to have an asymptomatic ACFAVF. His computed tomography angiography (CTA)-maximum intensity projection (MIP) showed the shunt point in the crista galli (CG), with the intradural drainer penetrating the destroyed bone of the CG. In case 2, a 78-year-old man had a past history of intracerebral hemorrhage and was found to have an ACFAVF. The rotational angiography (RA)-MIP showed the intraosseous fistula in the CG with the drainer passing through a tiny bone defect of the CG. In case 3, a 35-year-old man was investigated for epilepsy. The RA-MIP showed an osseous arteriovenous fistula (AVF) in the anterior cranial base, with the drainer penetrating the skull osteolytic site. In case 4, a 73-year-old woman was found to have an asymptomatic ACFAVF. Her RA-MIP showed the osseous AVF with the drainer penetrating the CG with bone erosion.

LESSSONS

All patients were diagnosed with anterior cranial fossa osseous AVF rather than dAVF, with bone erosion in the CG. These findings should be noted at the time of diagnosis and treatment.

Pediatric Petrous Apex Lesions: A Radiological Classification and Diagnostic Algorithm

The petrous apex (PA) is involved in a myriad of pathological conditions, some of which are exclusive in children. Diagnosis may be difficult due to vague clinical presentation, and local examination is challenging owing to its inaccessible location. This is further complicated by multiple unfused sutures and ongoing PA pneumatization in children. Cross-sectional imaging is vital for the evaluation of the PA lesions, due to their precarious location and proximity to the major neurovascular structures. Several classification systems have been proposed for these lesions based on their site of origin, solid or cystic appearance, surgical or non-surgical (no touch lesions) management, and benign or malignant nature. In this article, we emphasize the distinctive role of different cross-sectional imaging modalities in the diagnosis of pediatric PA lesions, with special attention to normal variants that should not be mistaken for pathology. We also propose a radiological classification and algorithmic approach to aid in the precise diagnosis and facilitate appropriate management of the various PA lesions in children.

Surgical disconnection of a hypoglossal canal dural arteriovenous fistula demonstrating rapid progression of medulla oblongata disturbance: illustrative case

BACKGROUND

Dural arteriovenous fistulas of the hypoglossal canal (HCDAVFs) with dominant drainage to perimedullary veins are extremely rare. These patients are prone to develop slow and progressive myelopathy, however, their clinical course has not been fully elucidated. We report an unusual case of HCDAVF in which the patient demonstrated rapid progression of hemiplegia and respiratory insufficiency.

OBSERVATIONS

An 82-year-old woman demonstrated motor weakness of the left extremities. T2-weighted magnetic resonance imaging showed a high intensity area in the right medulla oblongata and angiography revealed HCDAVF with dominant drainage to the anterior medullary vein through the anterior condylar vein. Within 3 days, her hemiparesis and respiratory function worsened, and she needed mechanical ventilation. Considering that venous congestion in the medulla oblongata could cause the symptoms, we immediately performed surgical obliteration of the anterior condylar vein. The disappearance of HCDAVF was confirmed by angiography and the patient was weaned from mechanical ventilation 3 days postoperatively. Her left hemiplegia gradually resolved and she was independent in daily life 8 months after the operation.

LESSONS

HCDAVFs with dominant drainage to the perimedullary veins can demonstrate rapid progression of medulla oblongata disturbance. Early disconnection should be considered to provide an opportunity for substantial recovery.

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

Diploic arteriovenous fistulas (AVFs) or intraosseous dural AVFs are rare arteriovenous shunts. A diploic AVF is formed between a meningeal artery and an intraosseous diploic vein or the transosseous emissary vein, and the nidus is located exclusively within the bone. Currently, endovascular embolization with a transvenous approach is considered the treatment of choice for most dural AVFs. However, in the absence of an accessible venous channel, an alternate treatment approach should be considered. Herein, we report a case of a diploic AVF that was treated using embolization with transosseous direct cannulation.

Bone-destructive osseous arteriovenous fistula at the jugular bulb mimicking a glomus jugular tumor

BACKGROUND

Some reports have described intraosseous arteriovenous fistulas showing osteolytic changes, but an osseous arteriovenous fistula (AVF) at the jugular bulb showing extensive bone destruction is a very rare disease.

CASE DESCRIPTION

A 60-year-old man presented with pulsatile tinnitus and right facial nerve palsy. Radiological imaging showed a large homogenously enhanced osteolytic lesion at the right jugular foramen. A cerebral angiogram showed a high-flow vascular lesion of the jugular bulb associated with retrograde sinus reflux, resulting in venous congestion of the deep venous system. These findings led us to misdiagnose this lesion as a glomus jugular tumor. However, combined arterial and venous angiography after transarterial embolization revealed the precise angioarchitecture, and we finally diagnosed this lesion as a high-flow osseous AVF at the jugular bulb. We performed transvenous embolization using a triple catheter technique. The lesion was successfully obliterated, and the 6-months angiogram showed no recurrence.

CONCLUSION

A rare case of high flow osseous AVF at the jugular bulb associated with osteolytic changes in the surrounding bony structure is reported. Although many hypervascular lesions at the jugular bulb are glomus tumors, bone destructive osseous AVF at the jugular bulb should be considered.

A Case of Intraosseous Petrous Bone Arteriovenous Fistula Complicated by Transient Worsening of Ipsilateral Hearing Following Transvenous Coil Embolization

Objective

We report a rare case of intraosseous arteriovenous fistula (AVF) in the petrous bone occluded by transvenous coil embolization, complicated by transient hearing loss postoperatively.

Case Presentation

A 55-year-old female patient underwent medical examination for vertigo and headache. CT showed an osteolytic lesion in the right petrous bone. CTA and DSA revealed an AVF that had caused bone erosion. We performed transvenous coil embolization to obtain complete occlusion of the fistula. Vertigo disappeared soon after the procedure, but hearing loss in the right side worsened to near deafness by that night. We started steroid pulse therapy and heparinization. The hearing gradually recovered to the preoperative level in 10 days.

Conclusion

It is important to pay attention to possible hearing loss in cases of transvenous coil embolization for intraosseous AVF in the petrous bone.

Arteriovenous fistula of the clival diploic vein associated with arteriovenous fistula of the posterior condylar canal

We herein report a rare case of a patient with a clival diploic vein arteriovenous fistula (AVF) associated with a posterior condylar canal AVF and discuss the radiological features of clival diploic vein AVF during decision-making on treatment strategies. A 69-year-old male patient with one-year history of pulsatile tinnitus was evaluated with magnetic resonance angiography, which revealed a dilated venous structure. Digital subtraction angiography revealed AVFs located in the clivus and posterior condylar canal. The clival diploic vein AVF was fed by the right internal maxillary artery and the petrous branch of middle meningeal artery and shed to the posterior condylar canal only through an intraosseous vein in the jugular tubercle. Although a catheter could not be navigated into the venous pouch in the clivus, the AVFs were successfully obliterated by transvenous embolization of the venous pouch in the posterior condylar canal.

Four-dimensional digital subtraction angiography for exploration of intraosseous arteriovenous fistula in the sphenoid bone

Background

Intraosseous arteriovenous fistula (AVF) is a rare clinical entity that typically presents with symptoms from their effect on surrounding structures. Here, we report a case of intraosseous AVF in the sphenoid bone that presented with bilateral abducens palsy.

Case Description

A previously healthy man presented with tinnitus for 1 month, and initial imaging suspected dural AVF of the cavernous sinus. Four-dimensional digital subtraction angiography (4D-DSA) imaging and a three-dimensional (3D) fused image from the bilateral external carotid arteries revealed that the shunt was in a large venous pouch within the sphenoid bone that was treated through transvenous coil embolization. His symptoms improved the day after surgery.

Conclusion

This is a case presentation of intraosseous AVF in the sphenoid bone and highlights the importance of 4D-DSA and 3D fused images for planning the treatment strategy.

Osseous arteriovenous fistulas in the dorsum sellae, clivus, and condyle

PURPOSE

Arteriovenous fistulas (AVFs) located in the cavernous sinus (CS), clivus, and condyle can be osseous shunts in nature. Here, we reviewed the angioarchitecture, clinical characteristics, and treatment results of AVFs in these lesions.

METHODS

Twenty-five patients with 27 lesions who underwent rotational angiography in our department between May 2013 and December 2019 were reviewed. We examined 20 CS AVFs, 2 clival AVFs, and 5 condylar AVFs. We divided the anatomical shunted pouches into five locations: the dorsum sellae (posteromedial of the CS), posterolateral wall of the CS, lateral wall of the CS, clivus, and condyle. We divided the AVFs into three categories: intraosseous, transitional, and nonosseous shunts. We analyzed the characteristics and treatment results.

RESULTS

A total of 33 shunted pouches or points were identified in 27 lesions. The dorsum sellae (n = 16) was the most frequent location. Fourteen AVFs (88%) in the dorsum sellae were osseous (intraosseous or transitional) shunts. All AVFs in the clivus or condyle were also osseous shunts. Eleven lesions (92%) of intraosseous and all lesions of transitional shunts exhibited bilateral external carotid artery involvement as feeders. Ten lesions (83%) of intraosseous shunts were treated with selective transvenous embolization of the shunted pouch with or without additional partial embolization of the sinus. Eleven (92%) intraosseous shunts were completely occluded, and symptom resolution was achieved in all intraosseous shunts.

CONCLUSION

Most of the CS AVFs with shunted pouches in the dorsum sellae and all of the AVFs in the clivus and condyle share similar characteristics.

Dural Arteriovenous Fistulas in the Parasellar Region Other Than the Cavernous Sinus

Besides cavernous sinus (CS) dural arteriovenous fistulas (AVFs), AVF may develop around the parasellar region. They can cause various symptoms, and some of them may show similar symptoms to those of CS dural AVF. Therefore, these AVFs may be misdiagnosed as CS dural AVFs. In this review, we divided parasellar AVFs into four groups based on their locations related to the CS: anterior group (orbit), anterolateral group (sphenoid wing), posteroinferior group (inferior petrosal sinus and clivus), and posterior group (superior petrosal sinus and petrosal vein). Although parasellar AVFs share common points, there are many differences between the four groups. We herein discuss commonalities and differences in parasellar AVFs based on a review of the literature and our experience.

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

BACKGROUND AND IMPORTANCE

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

CLINICAL PRESENTATION

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

CONCLUSION

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

Endovascular treatment for dural arteriovenous fistulas in the petroclival region

Petroclival region dural arteriovenous fistulas (DAVFs) are rare and difficult lesions to manage. They often have very complex anatomical structures and can be further divided into the superior petrosal sinus, petrous apex, inferior petrosal sinus, upper clival, and upper clival epidural-osseous DAVFs. Most petroclival region DAVFs should be treated due to their high Cognard grades. Currently, endovascular treatment (EVT) has become the first-line therapeutic option for petroclival region DAVFs. But not all the petroclival region DAVFs could be cured with EVT. When the arterial feeders are large or the DAVF is adjacent to the venous sinus, the success rate may be higher. In petroclival region DAVFs, if EVT can be performed successfully, satisfactory outcome can be anticipated. However, there are some inadvertent complications, which include cranial nerve palsy, subsequent sinus thrombosis, and migration embolization of the internal carotid artery and vertebral artery. Currently, a review of the EVT of petroclival region DAVFs is lacking. In this article, we performed a review of the relevant literature on this issue. In addition, some illustrative cases would be provided to elaborate these specific entities.

Hypoglossal canal dural arteriovenous fistula embolized under precise anatomical evaluation by selective intra-arterial injection computed tomography angiography

Dural arteriovenous fistula (DAVF) involving the hypoglossal canal is rare but increasingly reported. To achieve complete obliteration without a procedure-related complication, understanding of the precise anatomy of this DAVF is essential. Here, we describe a 72-year-old man who underwent selective intra-arterial injection computed tomography angiography which allowed us to understand the detailed anatomy of the complex DAVF regarding access routes and the target regions for transvenous embolization (TVE). With the aid of this novel neuroimaging technique successful target TVE was achieved safely and completely.

Intraosseous venous structures adjacent to the jugular tubercle associated with an anterior condylar dural arteriovenous fistula

PURPOSE

Although involvement of the osseous component with an anterior condylar dural arteriovenous fistula (AC-DAVF) has been frequently described, osseous venous structures in which AC-DAVFs develop have not been fully elucidated. We investigated osseous venous structures adjacent to the hypoglossal canal in normal controls and patients with AC-DAVFs.

METHODS

The study included 50 individuals with unruptured aneurysms as normal controls and seven patients with AC-DAVFs. Osseous venous structures adjacent to the hypoglossal canal in normal controls were analyzed using computed tomography (CT) digital subtraction venography. In patients with AC-DAVFs, the fistulous pouches, draining veins, and surrounding venous structures were examined using cone beam CT.

RESULTS

In 46.0% of laterals in normal controls, osseous venous structures were visualized within the jugular tubercle superomedially to the hypoglossal canal. We named these structures the jugular tubercle venous complex (JTVC). The JTVC was always continuous with the anterior condylar vein and was sometimes connected to surrounding venous channels. We detected nine fistulous pouches in the seven patients with AC-DAVFs. The fistulous pouches were in the JTVC (33.3%), anterior condylar vein (33.3%), and other venous channels within the exoccipital region (33.3%).

CONCLUSION

Although the JTVC is a venous structure frequently found in normal people, it had not been investigated until now. The venous channel between the anterior condylar vein and JTVC is a common origin site for AC-DAVFs, and it was associated with 66.6% of the AC-DAVF cases in the current study.

Gamma Knife surgery for clival epidural-osseous dural arteriovenous fistulas

OBJECTIVE Clival epidural-osseous dural arteriovenous fistula (DAVF) is often associated with a large nidus, multiple arterial feeders, and complex venous drainage. In this study the authors report the outcomes of clival epidural-osseous DAVFs treated using Gamma Knife surgery (GKS). METHODS Thirteen patients with 13 clival epidural-osseous DAVFs were treated with GKS at the authors' institution between 1993 and 2015. Patient age at the time of GKS ranged from 38 to 76 years (median 55 years). Eight DAVFs were classified as Cognard Type I, 4 as Type IIa, and 1 as Type IIa+b. The median treatment volume was 17.6 cm³ (range 6.2-40.3 cm³). The median prescribed margin dose was 16.5 Gy (range 15-18 Gy). Clinical and radiological follow-ups were performed at 6-month intervals. Patient outcomes after GKS were categorized as 1) complete improvement, 2) partial improvement, 3) stationary, and 4) progression. RESULTS All 13 patients demonstrated symptomatic improvement, and on catheter angiography 12 of the 13 patients had complete obliteration and 1 patient had partial obliteration. The median follow-up period was 26 months (range 14-186 months). The median latency period from GKS to obliteration was 21 months (range 8-186 months). There was no intracranial hemorrhage during the follow-up period, and no deaths occurred. Two adverse events were observed following treatment, and 2 patients required repeat GKS treatment with eventual complete obliteration. CONCLUSIONS Gamma Knife surgery offers a safe and effective primary or adjuvant treatment modality for complex clival epidural-osseous DAVFs. All patients in this case series demonstrated symptomatic improvement, and almost all patients attained complete obliteration.

Skull Base Osseous Arteriovenous Fistula-A Rare Clinical Entity: Case Report and Literature Review

PURPOSE

To describe a rare clinical entity of intraosseous skull base arteriovenous fistula managed with transvenous fistula embolization.

CASE PRESENTATION

A 57-year-old woman presented with complaints of headache and episodic tinnitus with progressive left-sided visual deterioration. Cross-sectional imaging of the head revealed multiple vascular channels in the sphenoid bone and in bilateral masticator spaces. Catheter angiography showed the presence of a large osseous arteriovenous fistula epicentered in the body of sphenoid and left pterygoid plates with arterial feeders from bilateral external carotid arteries and venous drainage into bilateral cavernous sinuses and the pterygoid venous plexus. She was managed by transvenous coil and liquid embolic agent (Squid 18) embolization of the venous sac with significant reduction of shunt. In the postprocedure period, the patient developed paradoxical worsening of symptoms due to central retinal vein occlusion.

CONCLUSIONS

Skull base osseous fistulae are uncommon clinical entities and fistulae centered within the sphenoid bone are very rare. The aim of this report was to highlight management issues associated with such a case and review the available literature on the subject.

Dural Arteriovenous Fistulae: Imaging and Management

Intracranial dural arteriovenous fistulae (DAVF) are pathologic arteriovenous shunts between meningeal arteries and dural venous sinuses or veins. They account for approximately 10% to 15% of all intracranial vascular malformations and are most common in middle-aged patients. DAVF are the most common vascular cause of pulsatile tinnitus. Digital subtraction angiography remains the gold standard for diagnosing these lesions. The pattern of venous drainage determines the type of DAVF and their risk for hemorrhage. Endovascular treatment has become a first-line option for their management. This article describes the natural history, clinical presentation, classification, imaging features, and management options of intracranial DAVF.

Transarterial N-Butyl-2-cyanoacrylate Embolization of an Intraosseous Dural Arteriovenous Fistula Associated With Acute Epidural Hematoma: Technical Case Report

BACKGROUND AND IMPORTANCE

Intraosseous dural arteriovenous fistulae (DAVF) are rare, especially those with drainage into the diploic venous system. The clinical presentation depends on the location of the lesion. This is the first report of an intraosseous DAVF associated with acute epidural hematoma.

CLINICAL PRESENTATION

A 25-year-old man presented with headache and nausea. Imaging of the brain revealed abnormal signals indicative of acute epidural hematoma in the right frontal convexity. Angiography demonstrated a DAVF in the region of the frontal bone. Right external carotid artery angiography showed that the DAVF was fed mainly by the right middle meningeal artery with drainage into diploic veins. Immediately after embolization of the middle meningeal and the distal internal maxillary artery with 17% N-butyl-2-cyanoacrylate, the shunt was completely occluded. The patient was discharged 4 days later without clinical complications.

CONCLUSION

Intraosseous DAVF can be treated by surgical resection or endovascular embolization. Curative treatment requires careful inspection of the angiographic architecture and microsurgical anatomy.

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 of intracranial dural arteriovenous fistulas

Endovascular treatment options for dural arteriovenous fistulas (DAVFs) have vastly expanded and become progressively safer in the last several years. Angiographic imaging systems have improved, catheter technology has advanced, and liquid embolic and coil options have increased. As a likely result, an increasing proportion of DAVFs are treated via an endovascular approach. In addition to allowing physicians to appreciate and treat lesions better, varied approaches have been developed. The "plug and push" technique and the new availability of dimethyl sulfoxide--compatible dual lumen balloons have allowed safer and more thorough transarterial treatments. Transvenous treatment has proved to be a valuable technique for some lesions. Hybrid approaches with surgical assisted access to vascular structures have been successfully used to treat more challenging fistulas.

Dural arteriovenous fistula discovered in patient presenting with recent head trauma

Patient

Male, 32

Final Diagnosis: Dural arterio-venous fistula

Symptoms: Eye redness • post-trauma headache • tinnitus

Medication: —

Clinical Procedure: Fistula embolization

Specialty: Neurology

Percutaneous transfacial direct embolization of an intraosseous dural arteriovenous fistula

BACKGROUND AND IMPORTANCE

An intraosseous dural arteriovenous fistula (DAVF) is a rare cerebrovascular disease. The fistulous connection occurs within intraosseous diploic or transosseous emissary veins causing dilated intraosseous vascular pouches. To the authors' knowledge, this report describes the first percutaneous transfacial direct embolization of an intraosseous DAVF.

CLINICAL PRESENTATION

A man in his 50s with blue rubber bleb nevus syndrome presented with headaches, imbalance, decreased visual acuity bilaterally, and left eye proptosis and chemosis. Imaging demonstrated an extensive intraosseous DAVF with dilated intraosseous vascular pouches throughout his cranial base and intraorbital venous congestion. He underwent staged endovascular treatment with the goal to improve his ocular symptoms. Transarterial and transvenous approaches failed to provide adequate access to the intraosseous vascular pouches. A direct, percutaneous transfacial approach was used to access the pouches for embolization with coils and liquid embolic material. Postoperative angiography demonstrated successful embolization of the pouch within the left pterygoid wing, reduced opacification of the intraosseous fistula, and elimination of intraorbital venous congestion. At 9-month follow-up, the patient's headaches had resolved, and his ocular symptomatology had improved.

CONCLUSION

Endovascular access to an intraosseous DAVF is limited by the size and location of the intraosseous vascular pouches. In this case, a direct transfacial approach under image guidance facilitated access and embolization, which led to an improvement in the patient's symptoms. This technique is a novel approach for DAVF management.

Intraosseous arteriovenous malformation of the sphenoid bone presenting with orbital symptoms mimicking cavernous sinus dural arteriovenous fistula: a case report

Intraosseous arteriovenous malformation (AVM) in the craniofacial region is rare. When it occurs, it is predominantly located in the mandible and maxilla. We encountered a 43-year-old woman with Klippel-Trenaunay syndrome affecting the right lower extremity who presented with a left orbital chemosis and proptosis mimicking the cavernous sinus dural arteriovenous fistula. Computed tomography angiography revealed an intraosseous AVM of the sphenoid bone. The patient's symptoms were completely relieved after embolization with Onyx. We report an extremely rare case of intraosseous AVM involving the sphenoid bone, associated with Klippel-Trenaunay syndrome.

Lesions of the petrous apex: classification and findings at CT and MR imaging

The petrous apex is a complex region of the central skull base that is surrounded by a number of important vascular and neural structures and can be home to a wide range of disease processes. Lesions arising in or spreading to the petrous apex cause varied and occasionally severe clinical sequelae, which typically result from mass effect or direct invasion of the cranial nerves, brainstem, or internal carotid artery. Because the petrous apex is not amenable to direct examination, cross-sectional imaging with computed tomography and magnetic resonance (MR) imaging plays an important role in diagnosis and characterization of lesions occurring there. Petrous apex lesions can be classified on the basis of their origin into the following categories: developmental lesions, inflammatory lesions, benign tumors, malignant tumors, vascular lesions, and osseous dysplasias. The most common lesions arising in the petrous apex are cholesterol granulomas, which can be reliably diagnosed with MR imaging due to their high signal intensity on both T1-weighted images and T2-weighted images. In addition, one should also be familiar with anatomic variants or pseudolesions in the petrous apex that can be mistaken for pathologic conditions.

A case of intraosseous dural arteriovenous fistulas involving diploic vein treated with transarterial onyx embolization

Intracranial dural arteriovenous fistulas (DAVFs) are abnormal arteriovenous connections that lie within the dura. Intraosseous DAVFs involving diploic venous system are extremely rare. A 46-year-old woman presented with headache and right pulsatile tinnitus for three weeks. The tinnitus started after yelling. Digital subtraction angiography revealed DAVF within the basal portion of right parietal bone along the middle meningeal artery (MMA) groove. The fistula was fed by frontal branch of right MMA and drained into right transverse sigmoid sinus junction through dilated middle meningeal vein. The intraosseous DAVF involving diploic vein was successfully obliterated with Onyx embolization via transarterial route.

Transvenous embolization of an intraosseous dural arteriovenous fistula of the anterior condylar vein with anomalous venous drainage causing ocular manifestations

We report a patient with a rare dural arteriovenous fistula of the anterior condylar vein, who presented with unusual clinical symptoms due to the anomalous venous drainage. The patient had progressive ocular signs, a dilated venous pouch at the skull base and, on angiography, retrograde venous drainage into the superior ophthalmic vein. Transvenous embolization of the venous pouch produced complete amelioration of the ocular symptoms. Such treatment may be curative for dural arteriovenous fistulas of the anterior condylar vein.