Epidural Arteriovenous Fistulas Research Articles

Embolization Tactics of Spinal Epidural Arteriovenous Fistulas.

PurposeSpinal epidural arteriovenous fistulas (SEDAVFs) show an epidural venous sac often with venous congestive myelopathy (VCM) due to intradural reflux at a remote level to which a transarterial approach would be difficult. We present 12 cases of SEDAVF with VCM and describe 3 main tactics for effective transarterial embolization.Materials and MethodsAmong 152 patients with spinal vascular malformations diagnosed in our tertiary hospital between 1993 and 2019, 12 SEDAVF patients with VCM were included. Three different transarterial embolization tactics were applied according to the vascular configuration and microcatheter accessibility. We evaluated treatment results and clinical outcomes before and after treatment.ResultsTransarterial embolization with glue (20–30%) was performed in all patients. The embolization tactics applied in 12 patients were preferential flow (n=2), plug-and-push (n=6), and filling of the venous sac (n=4). Total occlusion of the SEDAVF, including intradural reflux, was achieved in 11 (91.7%) of 12 patients, and partial occlusion was achieved in 1 patient. No periprocedural complications were reported. Spinal cord edema was improved in all patients for an average of 18 months after treatment. Clinical functional outcome in terms of the pain, sensory, motor, and sphincter scale and modified Rankin scores improved during a mean 25-month follow-up (6.3 vs. 3.3, P=0.002; 3.6 vs. 2.3, P=0.002, respectively).ConclusionEndovascular treatment for 12 SEDAVF patients with VCM achieved a total occlusion rate of 91.7% without any periprocedural complication. The combined embolization tactics can block intradural reflux causing VCM, resulting in overall good clinical outcomes.

Variations and management for patients with craniocervical junction arteriovenous fistulas: Comparison of dural, radicular, and epidural arteriovenous fistulas.

Background: Craniocervical junction arteriovenous fistulas (CCJAVFs) are known to be rare, but variations and clinical behaviors remain controversial.Methods: A total of 11 CCJAVF patients (M: F=9:2, age 54–77 years) were investigated. Based on the radiological and intraoperative findings, they were categorized into three types: dural AVF (DAVF), radicular AVF (RAVF), and epidural AVF (EDAVF).Results: There were four symptomatic patients (subarachnoid hemorrhage in two, myelopathy in one, and tinnitus in one) and seven asymptomatic patients in whom coincidental CCJAVFs were discovered on imaging studies for other vascular diseases (arteriovenous malformation in one, intracranial DAVF in two, ruptured cerebral aneurysm in two, and carotid artery stenosis in two). Of these 11 patients, 2 (18.2%) had multiple CCJAVFs. Of 14 lesions, the diagnoses were DAVF in 5, RAVF in 3, and EDAVF in 6 (C1–C2 level ratio =5:0, 2:1, 3:3). Patients with DAVF/RAVF in four lesions with intradural venous reflux underwent surgery, although an RAVF remained in one lesion after embolization/radiation. Since all six EDAVFs, two DAVFs, and one RAVF had neither feeder aneurysms nor significant symptoms, no treatment was provided; of these nine lesions, one DAVF and one RAVF remained unchanged, whereas six EDAVFs showed spontaneous obliteration within a year. Unfortunately, however, one DAVF bled before elective surgery.Conclusion: CCJAVFs have many variations of shunting site, angioarchitecture, and multiplicity, and they were frequently associated with coincidental vascular lesions. For symptomatic DAVF/RAVF lesions with intradural drainage, surgery is preferred, whereas asymptomatic EDAVFs without dangerous drainage may obliterate during their natural course.

Spinal epidural arteriovenous fistula with intradural venous reflux: The possibility of acquired origin caused by spinal stenosis and/or disc herniation

BackgroundSpinal epidural arteriovenous fistulas (SEAVFs) are relative rare lesions. The pathogenesis of these fistulas remains unclear. Our aim is to review cases of SEAVFs at our institution. MethodsWe reviewed a consecutive series of spinal vascular disease at our institution and collected all patients harboring SEAVFs. Medical charts were retrospectively reviewed regarding patient demographic data (i.e., gender and age), presenting symptoms and signs, previous history of spinal surgery or trauma, treatment methods, and neurological outcome after treatment. All image studies, including plain radiography, spinal MRI, MRA, and angiography were analyzed. ResultsWe identified 9 cases of lumbosacral SEAVFs with intradural venous reflux treated at our institution from June 2010 to August 2020. Their median age was 67 years, range 52–83 years. Only one patient had a history of trauma. Interestingly, our observations found that all fistulas are associated with spinal stenosis and/or disc herniation. An additional literature search about SEAVFs coexisting with spinal stenosis and/or disc herniation was performed and found another 19 cases with median age 69 years, range 39–83 years. Only 2 patients had a history of previous spinal surgery. The level of shunted pouch in all 28 patients was correlated with the level of spinal canal stenosis and/or disc herniation. Conclusions: Our study may provide an additional evidence supporting an acquired etiology of SEAVFs, which mainly manifest in late adulthood. It is possible that spinal stenosis and/or disc herniation may result in thrombosis or impairment of venous drainage, causing increased venous pressure, leading to fistulous formation.

Pressure Cooker Technique for Endovascular Treatment of Spinal Arteriovenous Fistulas: Experience in 15 Cases

Spinal arteriovenous fistulas are challenging to cure by endovascular means, with a risk of incomplete occlusion or delayed recurrence. The authors report herein their preliminary experience using the pressure cooker technique for the embolization of spinal arteriovenous fistulas.Fifteen patients (8 men; mean age, 60.3 years) underwent an endovascular treatment of a spinal arteriovenous fistula (12 dural spinal arteriovenous fistulas and 3 epidural spinal arteriovenous fistulas) in 2 different institutions using the pressure cooker technique. Two microcatheters could be navigated in the segmental artery in all patients using 2 guiding catheters. A proximal plug was achieved with highly concentrated cyanoacrylate ± coils. The liquid embolic agent injected to cure the fistula was diluted cyanoacrylate (n = 11) or ethylene-vinyl alcohol (n = 4). Technical and clinical complications were systematically recorded. Clinical and angiographic outcomes were systematically evaluated at follow-up.One (6.7%) procedure-related complication was recorded, which consisted of a transient radicular deficit, related to nerve root ischemia. Clinical improvement was observed in 10/14 (71%) patients for whom clinical follow-up was available. Complete spinal arteriovenous fistula occlusion on a follow-up angiography was observed in 11/12 patients (91.7%) for whom angiographic follow-up was available. One patient (8.3%) presented with a delayed recurrence at 29 months.The pressure cooker technique is feasible, with either glue or ethylene-vinyl alcohol, for the embolization of spinal arteriovenous fistulas. Our results suggest the safety and effectiveness of this technique.

Spinal Neurovascular Malformations in Klippel-Trenaunay Syndrome: A Single Center Study.

A number of studies have demonstrated spinal anomalies associated with Klippel-Trenaunay syndrome (KTS). To date, there are no large consecutive series examining the prevalence and subtype distribution of spinal neurovascular malformations in patients with KTS. To report the spectrum and incidence of spinal neurovascular manifestations in the KTS population. This was a cross-sectional study. Consecutive patients with definite KTS as defined by International Society for the Study of Vascular Anomalies criteria who underwent spinal neuroimaging at our institution were included. All studies were evaluated by a staff neuroradiologist and a senior radiology resident for the presence of developmental venous anomalies, cavernous malformations (CMs), and arteriovenous shunts (AVS). A total of 116 patients with definite KTS who underwent spinal neuroimaging were included. A total of 23 neurovascular anomalies were found in 19 patients (16.4%), including 4 patients with multiple anomalies. These included 5 patients with spinal cord CMs (4.3%), 14 patients with a paraspinal or epidural venous malformation (12.1%), and 4 patients with an AVS (3.4%). Of the AVS, 3 were epidural arteriovenous fistulas, 1 of which likely formed de novo in an epidural venous malformation. One was a conus medullaris arteriovenous malformation. Our study cohort of 116 KTS patients demonstrated a wide spectrum of spinal neurovascular anomalies with a relatively high prevalence. Potential phenotypic descriptions of KTS should include the possibility for spinal neurovascular anomalies.

Clinical and Imaging Characteristics of Spinal Dural Arteriovenous Fistulas and Spinal Epidural Arteriovenous Fistulas.

Spinal epidural arteriovenous fistulas (SEDAVFs) are an increasingly recognized form of spinal vascular malformation and are distinct from spinal dural arteriovenous fistulas (SDAVFs). Differentiating between these 2 entities is important as operative strategies often differ based on angioarchitecture. To compare demographic, clinical, anatomic, and imaging findings of SDAVFs and SEDAVFs. Consecutive patients diagnosed and/or treated for SDAVF or SEDAVF at our institution between January 2000 and November 2018 were included. Data were collected on demographics, clinical presentation, and imaging findings. All cross-sectional and angiographic imaging were reviewed. To compare continuous variables, t-test was used Chi-squared was used for categorical variables. A total of 169 patients were included. In total 47 patients had SEDAVFs and 122 patients had SDVAFs. Clinical presentation and magnetic resonance imaging (MRI) imaging findings were similar between the 2 groups. SEDAVF patients were significantly more likely to have an epidural venous pouch on gadolinium bolus MR angiography (MRA) (0.0%vs 92.1%, P<.0001). SEDAVFs were more commonly located in the lumbar and sacral spine than SDAVFs (85.1%vs 34.4%, P<.0001). When in the lumbar spine, SEDAVFs unlike SDAVFs were more likely to involve the most caudal segments (L4 and L5, P=.02). SEDAVF share clinical and radiological findings similar to SDAVFS, including high T2 cord signal, cord enhancement, and perimedullary flow voids on conventional MRI. However, they have a characteristic appearance on spinal MRA and DSA with a pouch of epidural contrast. SEDAVFs are more commonly located in the lumbosacral spine.

Spinal Epidural Fistulas–A Separate Entity to Dural Fistulas with Different Angioarchitecture and Treatment Approach

Spinal epidural arteriovenous fistulas (SEAVFs) are the rarest variety of spinal vascular malformation and are often misdiagnosed as type 1 spinal dural fistula. This retrospective study highlights the salient anatomic differentiating points of these entities and also highlights the importance of a planned endovascular treatment approach using different routes of access. Efficacy of the endovascular treatment at 3 months follow-up was also studied. We retrospectively reviewed 11 treated patients with SEAVF. Existence of epidural arteriovenous fistula in all these patients was confirmed by spinal angiography. The Aminoff-Logue Scale score was assigned both before and after the procedure. The statistical results were expressed as percentages, and the preprocedure scale was compared with the postprocedure scale at 3 months by using a nonparametric Wilcoxon signed-rank test. The patients ranged in age from 7 to 53 years, with male predominance. Paraparesis was the commonest symptom, and 1 patient had congestive cardiac failure caused by a large fistula. Location was mostly dorsolumbar with intradural venous reflux into the perimedullary venous system (Castilla type A) noted in 3/11(27%) patients, and the remaining 73% patients had Castilla type B1 with an enlarged epidural venous sac. Therapeutic embolization was performed from arterial, venous, or combined routes. The 3-month postprocedure clinical assessment showed statistically significant (P < 0.004) improvement in the Aminoff-Logue Scale score. The differentiating points between SEAVF compared with type 1 spinal dural fistula are emphasized. The study also highlights the importance of a good angiographic assessment to best access the fistula by arterial, venous, percutaneous, or combined routes. Endovascular treatment resulted in statistically significant clinical improvement at 3 months follow-up.

Spinal epidural arteriovenous fistula embolization with ethylene vinyl alcohol (EVOH) copolymer using the Scepter Mini dual-lumen balloon

Left unattended, spinal epidural arteriovenous fistulas (EAVFs) have a potentially severe clinical course. Embolization using ethylene vinyl alcohol (EVOH) copolymers through regular dual-lumen balloons has emerged as a potential option...

Microsurgical or endovascular strategy for complete obliteration of spinal arteriovenous shunts in a single-institute 10-year retrospective study

The objective of this retrospective study is to more fully understand the optimal strategy to manage spinal arteriovenous (AV) shunts. This study included a cohort of 35 patients with a diagnosis of spinal AV shunts who were treated over the past 10 years at a single institute. Angiographic diagnosis of intramedullary AV malformations (IM-AVM), perimedullary AV fistulas (PM-AVF), dural AV fistulas (D-AVF), or epidural AV fistulas (ED-AVF) was carefully made, and the microsurgical or endovascular strategy for them was determined at the interdisciplinary meeting consisting of neurospinal surgeons and endovascular specialists. Endovascular surgery was first considered whenever safely possible. Microscopic direct surgery using intraoperative image guidance was considered for cases in which endovascular access was challenging or not safely possible. Combined treatment was another option. The clinical condition was assessed using the modified Rankin scale (mRS). Seventeen of 35 cases were treated with microscopic direct surgery, 13 cases with endovascular surgery, and the remaining five cases with the combination. Complete angiographic obliteration was achieved in 30 of 35 cases (85.7%). Although residual AV shunts was recognized in 3 cases of IM-AVM, 1 case of PM-AVF and 1 case of ED-AVF, no angiographic recurrence was present with an average postoperative follow-up period of 44 months. The average mRS before surgery was 2.37 and significantly improved to 1.94 at the most recent follow-up. Interdisciplinary collaboration between neurospinal surgeons and endovascular specialists should be standard to achieve safe and successful outcomes in treating such rare and difficult spinal disorders.

Four-dimensional digital subtraction angiography for exploration of spinal cord vascular malformations: preliminary experience

BackgroundThe precise understanding of the angioarchitecture of spinal vascular malformations (SVMs) is often difficult to reach with conventional digital subtraction angiography (DSA). The purpose of our study was to evaluate...

Microsurgical versus endovascular treatment of spinal epidural arteriovenous fistulas with intradural venous drainage: a multicenter study of 81 patients.

Spinal arteriovenous shunts are rare vascular lesions and are classified into 4 types (types I-IV). Due to rapid advances in neuroimaging, spinal epidural AVFs (edAVFs), which are similar to type I spinal dural AVFs (dAVFs), have recently been increasingly reported. These 2 entities have several important differences that influence the treatment strategy selected. The purposes of the present study were to compare angiographic and clinical differences between edAVFs and dAVFs and to provide treatment strategies for edAVFs based on a multicenter cohort. A total of 280 consecutive patients with thoracic and lumbosacral spinal dural arteriovenous fistulas (dAVFs) and edAVFs with intradural venous drainage were collected from 19 centers. After angiographic and clinical comparisons, the treatment failure rate by procedure, risk factors for treatment failure, and neurological outcomes were statistically analyzed in edAVF cases. Final diagnoses after an angiographic review included 199 dAVFs and 81 edAVFs. At individual centers, 29 patients (36%) with edAVFs were misdiagnosed with dAVFs. Spinal edAVFs were commonly fed by multiple feeding arteries (54%) shunted into a single or multiple intradural vein(s) (91% and 9%) through a dilated epidural venous plexus. Preoperative modified Rankin Scale (mRS) and Aminoff-Logue gait and micturition grades were worse in patients with edAVFs than in those with dAVFs. Among the microsurgical (n = 42), endovascular (n = 36), and combined (n = 3) treatment groups of edAVFs, the treatment failure rate was significantly higher in the index endovascular treatment group (7.5%, 31%, and 0%, respectively). Endovascular treatment was found to be associated with significantly higher odds of initial treatment failure (OR 5.72, 95% CI 1.45-22.6). In edAVFs, the independent risk factor for treatment failure after microsurgery was the number of intradural draining veins (OR 17.9, 95% CI 1.56-207), while that for treatment failure after the endovascular treatment was the number of feeders (OR 4.11, 95% CI 1.23-13.8). Postoperatively, mRS score and Aminoff-Logue gait and micturition grades significantly improved in edAVFs with a median follow-up of 31 months. Spinal epidural AVFs with intradural venous drainage are a distinct entity and may be classified as type V spinal vascular malformations. Based on the largest multicenter cohort, this study showed that primary microsurgery was superior to endovascular treatment for initial treatment success in patients with spinal edAVFs.

Clinical and angioarchitectural characteristics of spinal vascular malformations of the cervical spine.

Vascular malformations of the cervical spine are exceedingly rare. To date there have been no large case series describing the clinical presentation and angioarchitectural characteristics of cervical spine vascular malformations. The authors report their institutional case series on cervical spine vascular malformations diagnosed and treated at their institution. The authors retrospectively reviewed all patients with spinal vascular malformations from their institution from January 2001 to December 2018. Patients with vascular malformations of the cervical spine were included. Lesions were characterized by their angioarchitectural characteristics by an interventional neuroradiologist and endovascular neurosurgeon. Data were collected on clinical presentation, imaging findings, treatment outcomes, and long-term follow-up. Descriptive statistics are reported. Of a total of 213 patients with spinal vascular malformations, 27 (12.7%) had vascular malformations in the cervical spine. The mean patient age was 46.1 ± 21.9 years and 16 (59.3%) were male. The most common presentations were lower-extremity weakness (13 patients, 48.1%), tetraparesis (8 patients, 29.6%), and lower-extremity sensory dysfunction (7 patients, 25.9%). Nine patients (33.3%) presented with hemorrhage. Fifteen patients (55.6%) had modified Rankin Scale scores of 0-2 at the time of diagnosis. Regarding angioarchitectural characteristics, 8 patients (29.6%) had intramedullary arteriovenous malformations (AVMs), 5 (18.5%) had epidural arteriovenous fistulas (AVFs), 4 (14.8%) had paraspinal fistulas, 4 (14.8%) had mixed epidural/intradural fistulas, 3 (11.1%) had perimedullary AVMs, 2 (7.4%) had dural fistulas, and 1 patient (3.7%) had a perimedullary AVF. This retrospective study of 27 patients with cervical spine vascular malformations is the largest series to date on these lesions. The authors found substantial angioarchitectural heterogeneity with the most common types being intramedullary AVMs followed by epidural AVFs, paraspinal fistulas, and mixed intradural/extradural fistulas. Angioarchitecture dictated the clinical presentation as intradural shunts were more likely to present with hemorrhage and acute onset myelopathy, while dural and extradural shunts presented as either incidental lesions or gradually progressive congestive myelopathy.

Progressive myelopathy due to spinal epidural arteriovenous fistula with retrograde venous drainage

Progressive myelopathy due to spinal epidural arteriovenous fistula with retrograde venous drainage

Clipping of an anterior spinal artery aneurysm using an endoscopic fluorescence imaging system for craniocervical junction epidural arteriovenous fistula: technical note.

The authors report the case of a 78-year-old man with a craniocervical junction epidural arteriovenous fistula who presented with subarachnoid hemorrhage from a ruptured anterior spinal artery (ASA) aneurysm. Because endovascular embolization was difficult, a posterolateral approach was chosen and a novel endoscopic fluorescence imaging system was utilized to clip the aneurysm. The fluorescence imaging system provided clear and magnified views of the ventral spinal cord simultaneously with the endoscope-integrated indocyanine green videoangiography, which helped safely obliterate the ASA aneurysm. With the aid of this novel imaging system, surgeons can appreciate and manipulate complex vascular pathologies of the ventral spinal cord through a posterolateral approach, even when the lesion is closely related to the ASA.

A Patient with Spinal Epidural Arteriovenous Fistula Cured by Balloon-assisted Transarterial Embolization under Flow Control

A Patient with Spinal Epidural Arteriovenous Fistula Cured by Balloon-assisted Transarterial Embolization under Flow Control

Osseous versus Nonosseous Spinal Epidural Arteriovenous Fistulas: Experiences of 13 Patients.

Spinal epidural arteriovenous fistulas are rare vascular malformations. We present 13 patients with spinal epidural arteriovenous fistulas, noting the various presenting symptom patterns, imaging findings related to bone involvement, and outcomes. Among 111 patients with spinal vascular malformations in the institutional data base from 1993 to 2017, thirteen patients (11.7%) had spinal epidural arteriovenous fistulas. We evaluated presenting symptoms and imaging findings, including bone involvement and mode of treatment. To assess the treatment outcome, we compared initial and follow-up clinical status using the modified Aminoff and Logue Scale of Disability and the modified Rankin Scale. The presenting symptoms were lower back pain (n = 2), radiculopathy (n = 5), and myelopathy (n = 7). There is overlap of symptoms in 1 patient (No. 11). Distribution of spinal epidural arteriovenous fistulas was cervical (n = 3), thoracic (n = 2), lumbar (n = 6), and sacral (n = 2). Intradural venous reflux was identified in 7 patients with congestive venous myelopathy. The fistulas were successfully treated in all patients who underwent treatment (endovascular embolization, n = 10; operation, n = 1) except 2 patients who refused treatment due to tolerable symptoms. Transarterial glue (n = 7) was used in nonosseous types; and transvenous coils (n = 3), in osseous type. After 19 months of median follow-up, the patients showed symptom improvement after treatment. Although presenting symptoms were diverse, myelopathy caused by intradural venous reflux was the main target of treatment. Endovascular treatment was considered via an arterial approach in nonosseous types and via a venous approach in osseous types.

Endovascular Occlusion of Epidural Spinal Dural Arteriovenous Fistula: 2-Dimensional Operative Video.

Epidural spinal fistulas are relatively uncommon spinal vascular malformations. With advanced neuroimaging, these lesions, though once considered quite rare, are being diagnosed with increasing frequency. Epidural spinal fistulas differ from the more common type I spinal dural fistula by the location of the arteriovenous shunt, which is between an artery and an epidural vein. The epidural vein often having secondary retrograde drainage into an intradural spinal vein.1 Differentiation between epidural fistulas and the more common type I dural spinal fistula is impossible based on clinical and magnetic resonance imaging criteria but is done only based on catheter angiography. Differentiation between the 2 is very important because in patients with epidural fistulas, the goal should be occlusion of the epidural vein draining the fistula, as occlusion of the intradural vein alone might result in persistence of the shunt and possible recruitment of another intradural vein, either contralateral or at a different level. Moreover, most epidural spinal arteriovenous fistulas are localized ventrally in the epidural space and might not be simple to expose and exclude surgically. In this video, we present the case of an epidural spinal arteriovenous fistula successfully treated with Onyx. Figure in video, from Brinjikji W et al1, used with permission of Mayo Foundation for Medical Education and Research, all rights reserved. Disclosure The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.Watch now at https://academic.oup.com/ons/article-lookup/doi/10.1093/ons/opy031 {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Endovascular Occlusion of Epidural Spinal Dural Arteriovenous Fistula: 2-Dimensional Operative Video","caption":"","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_gxsx6b76"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]}

Spinal Epidural Arteriovenous Fistula with Perimedullary Venous Reflux: Clinical and Neuroradiologic Features of an Underestimated Vascular Disorder.

The purpose of this study was to discuss the clinical and radiologic characteristics of spinal epidural arteriovenous fistulas (SEAVF) and demonstrate their specific angiomorphology in a single-center series. Thirteen consecutive patients were diagnosed with SEAVF at RWTH Aachen University Hospital between 2006 and 2018 and were included in this study. All patients had MR imaging and DSA before treatment; 10 of these 13 patients received contrast-enhanced MRA (CE-MRA). The mean patient age was 72 ± 8 years. Paraparesis was present in 12 (92%) patients. Sphincter dysfunction and sensory symptoms were observed in 7 (54%) and 6 (46%) patients, respectively. The mean duration of symptoms was 6 ± 8 months. Congestive myelopathy on MR imaging was present in all patients. Prominent arterialized perimedullary veins were demonstrated in only 3 cases. CE-MRA revealed arterialized perimedullary veins and an arterialized epidural pouch in 9/10 (90%) patients, mostly located ventrolaterally. DSA demonstrated a multisegmental extension of the arterialized ventrolateral epidural pouch in 6 (46%) cases. An intradural radicular drainage vein was localized distant from the original fistula point in 3 (23%) patients. Congestive myelopathy with an acute/subacute clinical course was the dominant finding in spinal epidural arteriovenous fistulas. CE-MRA is a powerful diagnostic tool for identifying arterialized perimedullary veins as well as an arterialized epidural pouch. While arterialized perimedullary veins frequently present with only mild enlargement and elongation in spinal epidural arteriovenous fistulas, the arterialized epidural pouch is frequently located ventrolaterally and may extend over several vertebral levels. DSA remains the criterion standard to precisely visualize a spinal epidural arteriovenous fistula and its intradural radicular drainage vein, which may be located distant from the fistulous point.

Dilated Vein of the Filum Terminale on MRI: A Marker for Deep Lumbar and Sacral Dural and Epidural Arteriovenous Fistulas

Conventional MR imaging can provide important clues regarding the location of a spinal vascular malformation. We hypothesized that a dilated vein of the filum terminale, identified as a curvilinear flow void on T2WI, could be an imaging marker for a lower lumbar (L3-L5) or sacral fistula. We retrospectively identified all spinal dural and spinal epidural arteriovenous fistulas from 2 large tertiary referral centers from 2005 to 2018. All patients had a lumbar spinal MR imaging and a conventional spinal angiography. Images were reviewed by 2 neuroradiologists who categorized the level of the arterial feeder to the fistula and the presence or absence of a dilated vein of the filum terminale on T2WI and T1 postcontrast images. We calculated the sensitivity, specificity, positive predictive value, and negative predictive value of the presence of a dilated filum terminale vein for a deep lumbar or sacral fistula. One hundred sixty-two patients were included. An enlarged filum terminale vein was identified in 39 patients. Sensitivity, specificity, positive predictive value, and negative predictive value of the presence of a dilated filum terminale vein for a deep lumbar or sacral fistula were 86%, 98.3%, 94.9%, and 95.1%, respectively. The presence of a dilated vein of the filum terminale can accurately localize a spinal dural arteriovenous fistula/spinal epidural arteriovenous fistula to the lower lumbar or sacral spine in patients being evaluated for such lesions. This finding can be used to facilitate both noninvasive and conventional spinal angiography.

Spinal Arteriovenous Vascular Malformations in Patients with Neural Tube Defects.

Neural tube defects, such as tethered cord, intradural lipoma, or myelomeningocele may coexist with spinal vascular malformations. The coexistence of these 2 rare entities is suggestive of a causal relationship between them, which may lead to further understanding of their pathogenesis. We present a series of 6 patients with epidural spinal arteriovenous fistulas associated with neural tube defects. We retrieved cases of spinal vascular malformations associated with neural tube defects seen at our institution. The clinical presentation, MR imaging/MRA and angiographic imaging, treatment outcomes, and long-term neurologic outcomes were analyzed. Descriptive statistical analyses are reported. Six patients with epidural arteriovenous fistulas and neural tube defects were included in this study. The mean age at presentation was 42 years, and the most common presenting symptoms were lower extremity weakness followed by sensory disturbances and bladder/bowel dysfunction. In most cases (5/6), the fistulas were located at the sacral level. All cases were fed by the lateral sacral artery (6/6). Four patients had prior spine surgery, but the fistula was in the operative bed in 2 cases. All fistulas were extradural with secondary intradural venous drainage. Five patients underwent transarterial embolization with Onyx, and 1 patient had a treatment-related complication. It is conceivable that there is a pathophysiologic link between neural tube defects and development of spinal vascular malformations. Delayed neurologic deterioration or high conus signal in a patient with a neural tube defect should suggest the possibility of such an association.