Spinal Epidural Arteriovenous Fistulas Research Articles

Two pediatric observations of spinal extradural arteriovenous fistulas presenting with epidural hemorrhages and cord compression.

We report two cases of acute spinal cord compression in children with low-flow spinal epidural arteriovenous fistulas (SEAVFs) and discuss the clinical presentation and management of these vascular anomalies. While most low-flow SEAVFs without radiculomedullary drainage are benign lesions typically diagnosed incidentally, we suggest that asymptomatic lesions may warrant aggressive management in specific circumstances, including lesions diagnosed at an early age or in patients under anticoagulation therapy. Our observations also emphasize that patients with a "spontaneous" epidural hemorrhage should undergo dedicated preoperative or postoperative vascular imaging to identify a possible underlying vascular anomaly.

Angiographic challenges of spinal dural and epidural arteriovenous fistulas: report on 45 cases.

The localization of the fistula level in spinal dural arteriovenous fistulas (dAVFs) and epidural arteriovenous fistulas (edAVFs) remains a diagnostic challenge. Consecutive patients with spinal dAVFs and edAVFs in the thoracic, lumbar, and sacral regions were included. The primary endpoint was to describe the characteristics of patients who required angiography with multiple catheterizations of segmental arteries (10 or more). Forty-five patients (median age 69years; male 89%; dAVFs, n = 31; edAVFs, n = 14) were included. Spinal dAVFs commonly developed in the thoracic region and edAVFs in the lumbosacral region. Fistulas were predicted at the correct level or plus/minus 2 level in less invasive examinations using multi-detector CT angiography (n = 28/36, 78%) and/or contrast-enhanced MR angiography (n = 9/14, 64%). We encountered diagnostic challenges in the localization of fistulas in 6 patients. They underwent angiography a median of 2 times. In each patient, spinal levels were examined at a median of 25 levels with a median radiation exposure of 3971mGy and 257ml of contrast. Fistulas were finally localized at the high thoracic region (T4-6) in 3 patients, the sacral region (S1-2) in 2, and the lumbar region (L3) in 1. Four patients were diagnosed with edAVFs and 2 with dAVFs. The correlation coefficient between the fistula level and the rostral end of the intramedullary T2 high-signal intensity on MRI was interpreted as none. In patients in whom less invasive examinations failed for fistula localization, high thoracic or sacral AVFs need to be considered.

Open surgical ligation of a thoracic spinal epidural arteriovenous fistula causing thoracic myelopathy: illustrative case.

Spinal epidural arteriovenous fistulas (eAVFs) are rare spinal vascular malformations characterized by an abnormal connection from the paraspinal and paravertebral system to the epidural venous plexus. This contrasts with the more frequently seen spinal dural AVF, where the fistula is entirely intradural. Although endovascular repair is commonly performed for spinal eAVF, few cases require open surgical ligation. The authors present a case of a 74-year-old male with progressive thoracic myelopathy secondary to a spinal eAVF. Thoracic magnetic resonance imaging (MRI) showed intramedullary T2 signal hyperintensity from T8 to T12. Spinal angiography revealed a primary arterial supply from the right T11 segmental artery and minor supply from the left T11 branches with drainage into the ventral epidural space. The patient underwent T11-12 laminectomy and complete right T11-12 facetectomy for ligation of the fistula with T11-L1 fusion. A postoperative spinal angiogram showed resolution of the fistula. Postoperatively, the patient's myelopathy improved, and MRI showed a decrease in T2 cord intensity. Spinal eAVFs are rare lesions that differ from the more commonly seen intradural dural AVF in that the abnormal connection is in the epidural space, and they are often associated with a dilated epidural venous pouch. Treatment involves endovascular, open surgical, or combined approaches.

Spinal dural and epidural arteriovenous fistula: Recurrence rate after surgical and endovascular treatment.

Spinal dural arteriovenous fistula consist of an heterogenous group of vascular malformation often causing severe neurological deficit due to progressive myelopathy. This type of malformation could be associated with subarachnoid or subdural hemorrhage inside the spinal canal. In the English literature surgical treatment is regarded as the best option if compared to endovascular procedure, being the latter associated with an increased risk of relapse despite its less invasiveness. In this study a retrospective analysis of 30 patients with spinal dural and epidural fistula associated with perimedullary venous congestion was undertaken. The radiological and clinical presentation of each patient is analyzed, and the grade of myelopathy is classified through the mJOA score. A total number of 31 out of 41 collected procedures (22 surgery vs. 19 endovascular) were dural fistulas while the remaining 10 were classified as epidural. A 46% recurrence rate for endovascular treatment against 0% for surgical (p-value 0.004) was described for dural fistulas, while in the epidural fistula group the rate of recurrence was 80% and 20% respectively for endovascular and surgery treatment (p-value 0.6). According to the results, surgical treatment could be considered as first-line treatment for spinal dural arteriovenous fistulas. Endovascular embolization can be proposed in selected cases, as a less invasive technique, for elderly patients or with important comorbidities. In spinal epidural arteriovenous fistulas, in view of the greater invasiveness of the surgical treatment and the non-significant difference in terms of recurrence risk between the two techniques, endovascular treatment could be proposed as a first choice treatment; in the event of a recurrence, a surgical intervention will instead be proposed in a short time.

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.

Thoracolumbar intraosseous spinal epidural arteriovenous fistulas after vertebral compression fracture: A case report and literature review

Background: The pathophysiology of spinal epidural arteriovenous fistulas (SEAVFs) with perimedullary venous drainage remains to be elucidated. This report describes a case of intraosseous SEAVF in a patient with a history of a thoracolumbar vertebral fracture at the same level 10 years before presenting with progressive myelopathy secondary to retrograde venous reflux into the perimedullary vein.Case Description: A 71-year-old man presenting with progressive paraparesis was diagnosed with a SEAVF involving a previous Th12 and L1 vertebral compression fracture on which feeders from multiple segmental arteries converged. The interesting feature of this case was that the fistula was located in the fractured vertebral body. The fistula was totally obliterated by transarterial embolization of the segmental arteries followed by symptom improvement.Conclusion: We presented a rare case of an intraosseous SEAVF secondary to a thoracolumbar compression fracture with perimedullary venous reflux causing progressive myelopathy. The fistula was located in the fractured vertebral body.

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...

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.

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.

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.

Angiographic and Clinical Characteristics of Thoracolumbar Spinal Epidural and Dural Arteriovenous Fistulas.

The purpose of this study is to compare the angiographic and clinical characteristics of spinal epidural arteriovenous fistulas (SEAVFs) and spinal dural arteriovenous fistulas (SDAVFs) of the thoracolumbar spine. A total of 168 cases diagnosed as spinal dural or extradural arteriovenous fistulas of the thoracolumbar spine were collected from 31 centers. Angiography and clinical findings, including symptoms, sex, and history of spinal surgery/trauma, were retrospectively reviewed. Angiographic images were evaluated, with a special interest in spinal levels, feeders, shunt points, a shunted epidural pouch and its location, and drainage pattern, by 6 readers to reach a consensus. The consensus diagnoses by the 6 readers were SDAVFs in 108 cases, SEAVFs in 59 cases, and paravertebral arteriovenous fistulas in 1 case. Twenty-nine of 59 cases (49%) of SEAVFs were incorrectly diagnosed as SDAVFs at the individual centers. The thoracic spine was involved in SDAVFs (87%) more often than SEAVFs (17%). Both types of arteriovenous fistulas were predominant in men (82% and 73%) and frequently showed progressive myelopathy (97% and 92%). A history of spinal injury/surgery was more frequently found in SEAVFs (36%) than in SDAVFs (12%; P=0.001). The shunt points of SDAVFs were medial to the medial interpedicle line in 77%, suggesting that SDAVFs commonly shunt to the bridging vein. All SEAVFs formed an epidural shunted pouch, which was frequently located in the ventral epidural space (88%) and drained into the perimedullary vein (75%), the paravertebral veins (10%), or both (15%). SDAVFs and SEAVFs showed similar symptoms and male predominance. SDAVFs frequently involve the thoracic spine and shunt into the bridging vein. SEAVFs frequently involve the lumbar spine and form a shunted pouch in the ventral epidural space draining into the perimedullary vein.

A New Type of Spinal Epidural Arteriovenous Fistulas Causes Spinal Epidural Hemorrhage: An Analysis of Five Cases and Natural History Consideration.

Spinal epidural arteriovenous fistulas (SEDAVFs) are peculiar and poorly understood lesions with a poorly understood natural history. They usually are subclassified into 2 types according to their drainage components. This study aimed to describe a new type ofSEDAVFs that is featured with a unique drainage pattern and present our natural history hypothesis of SEDAVFs. Five SEDAVF cases of the new type werereviewed retrospectively from a high case-volume spinal vascular malformation database. The clinical manifestations, neuroradiologic findings, angioarchitecture, treatment strategies, and clinical outcomes were assessed. All patients presented with spontaneous spinal epidural hematoma, and 2 of them exhibited rebleeding. The median age at the initial episode was 20 years. Spinal digital subtraction angiography revealed slow-flow epidural fistulas drained by spinal epidural venous plexus without intradural drainage or engorged venous pouches in all 5 patients. Three patients underwent microsurgical treatment. The outcomes of all of the patients were favorable. Our study reported a special type of hemorrhagic SEDAVF without an intradural drainage component or epidural mass effect. The key diagnostic clue was early opacification of spinal epidural venous plexus on spinal angiogram. We believe SEDAVFs may form at an early age and gradually develop with time. Different types of SEDAVFs may represent different developing stages of one disease, and our type may represent the early stage of SEDAVFs.

Clinical presentation and treatment outcomes of spinal epidural arteriovenous fistulas.

OBJECTIVE Spinal epidural arteriovenous fistulas (SEDAVFs) constitute a rare but treatable cause of vascular myelopathy and are a different subtype from the more common Type I spinal dural AVFs. The purpose of this study was to review a consecutive series of SEDAVFs from a single institution and report on the clinical presentations, functional status, and treatment outcomes. METHODS The authors identified all SEDAVFs treated at their institution from 2005 to 2015. SEDAVFs were defined as spinal AVFs in which the fistulous connection occurred in the epidural venous plexus. The clinical presentation, functional status, immediate treatment outcomes, and long-term neurological outcomes were analyzed. RESULTS Twenty-four patients with SEDAVFs were included in this study. The patients' mean age at presentation was 66.9 years. The most common presenting symptoms were pain and numbness (22 patients, 91.7%), followed by lower-extremity weakness (21 patients, 87.5%). The mean duration of symptoms prior to diagnosis was 11.8 months. Eighteen patients (75.0%) were treated with endovascular therapy alone, 4 (16.7) with surgery, and 2 (8.3%) with a combination of techniques. There was 1 major treatment-related complication (4.2%). Fifteen patients (62.5%) had improvement in disability, and 12 patients (54.5%) had improvement in sensory symptoms. CONCLUSIONS SEDAVFs often present with lower-extremity motor dysfunction and sensory symptoms. With the availability of newer liquid embolic agents, these lesions can be effectively treated with endovascular techniques. Surgery is also effective at treating these lesions, especially in situations where endovascular embolization fails or is not safe and in patients presenting with mass effect from compressive varices.

E-091 atraumatic epidural arteriovenous fistulae of the spine with intradural drainage: case series and review of imaging and treatment methods

Introduction/purpose Spinal epidural arteriovenous fistulas (SEDAVF) with intradural venous drainage are a rare and poorly understood vascular malady of the spine – one that is both potentially neurologically devastating as well as potentially curable. Several theories have been postulated as to their nature and causative incidents, but they remain a mystery. These types of fistulae are broadly differentiated into two categories: post-traumatic (usually in the cervical spine) and atraumatic (usually lumbar spine). Materials/methods Retrospective search of imaging and clinical data including patient demographics, angiographic findings, surgical results (where applicable), and follow up clinical information was performed in patients who had conventional spinal angiography over the past 10 years. Results We report a series of 14 patients with atraumatic spinal epidural arteriovenous fistula with intradural drainage treated at our institution. Eleven had intradural drainage of the epidural fistula. All of these patients presented with insidious onset of lower extremity weakness mimicking SDAVF both in presentation and on imaging. All patients underwent diagnostic spinal angiogram, and 12/14 (85.7%) had at least one endovascular intervention. Seven of the 15 patients underwent open surgery for their fistula. Ten of the patients (71.4%) had fistulae in the lumbar spine, with 2 patients presenting with an atraumatic SEDAVF in the thoracic spine and 2 in the cervical spine. Eleven of the patients (including all of the patients with cervical and thoracic level SEDAVF) had disc bulges resulting in greater than 25% spinal canal stenosis at an adjacent level. 50% of patients were cured from endovascular methods alone, 14.3% cured purely surgically, and 35.7% cured with a combined approach. Conclusion Because of the variability in venous anatomy and the nature of the circuitous drainage pathway some of these fistulae take, the atraumatic fistulae with intradural venous drainage (a high-risk feature) can be missed if one hasn’t already thought of the diagnosis. All of the patients with intradural drainage had adjacent disc bulges, which may be contributory to the intradural routing of the venous drainage. The epidural space is significantly narrowed by the disc bulge resulting in increased resistance to venous outflow in the epidural space necessitating the drainage to reroute intradurally. Eleven patients with intradural drainage of an epidural fistula in patients presenting with myelopathy is the largest series of such patients reported to date. We also discuss embolization resulting in cure or partial cure in over 85% of the patients in our series, demonstrating the importance of a thorough knowledge of this entity on the part of the neurointerventionalist. Disclosures A. Nicholson: None. M. Amans: None. F. Settecase: None. S. Hetts: None. D. Cooke: None. C. Dowd: None. R. Higashida: None. M. Lawton: None. V. Halbach: None.

O-014 initial mri diagnosis in 132 cases of angiographically confirmed spinal vascular malformations

Purpose To evaluate the accuracy of MRI for the diagnosis of spinal vascular malformations (SVM). Materials and methods We reviewed 133 consecutive patients with 142 high-flow SVMs confirmed by spinal angiography between 1999 and 2104. The initial MRI diagnosis was available in 132 instances. MRI was considered positive when a SVM was listed in the differential diagnosis or when spinal angiography was recommended. It was considered falsely negative otherwise (i.e., no or wrong diagnoses). The lesions included 89 spinal dural or epidural arteriovenous fistulas (SDAVF/SEAVF) (67.4%), 26 perimedullary arteriovenous fistulas (PmAVF) (19.7%), 8 spinal arteriovenous malformations (SAVM) (6.1%), 3 SAVM/PmAVFs (2.3%), and 6 paravertebral arteriovenous fistulas (ParAVF) (4.5%). The PmAVFs were subdivided into 8 Type 1 (6.1%), 15 Type 2 (11.4%), and 3 Type 3 (2.3%). Results The initial MRI diagnosis was falsely negative in 50% of cases (66 SVMs in 63 patients). Missed lesions included 54 SDAVF/SEAVFs (81.8%) and 12 PmAVFs (18.2%). No case of SAVM, SAVM/PmAVF, or ParAVF was missed. When grouped, slow-flow lesions (54 SDAVF/SEAVFs and 8 PmAVF Type 1) accounted for 93.9% of the false negative MRIs, with a 63.9% false negative ratio (62 missed lesions out of 97). The most common MRI misdiagnoses included inflammatory conditions (transverse myelitis) (46.0%), spine degenerative disease (11.1%), tumors (7.9%), and stroke (3.2%). No specific diagnosis was offered in 31.7% of cases. Conclusion The initial MRI in patients with SVMs was falsely negative in half of the reviewed cases. Slow-flow spinal arteriovenous fistulas (SDAVF, DEAVF, and PmAVF Type 1) were particularly insidious lesions, missed in about two-thirds of instances. About half the patients received an incorrect diagnosis of TM and were threated accordingly. Most patients with no specific MRI diagnosis were treated empirically for TM as well. Missed initial diagnoses not only delay adequate treatment for conditions with narrow therapeutic windows, but also result in the introduction of inappropriate, often deleterious management (e.g., high-dose steroids or plasma exchange). Our findings, based on patients with angiographically confirmed lesions, likely underestimate the true rate of false-negative MRI diagnoses in patients with SVMs. Disclosures D. Sorte: None. E. Wyse: None. E. Orru9: None. P. Gailloud: None.

Lumbar spinal epidural arteriovenous fistula with perimedullary venous drainage after endoscopic lumbar surgery.

Spinal epidural arteriovenous fistulas (AVFs) with perimedullary venous drainage are rare. This report describes a case of lumbar epidural AVF in a patient with a history of endoscopic lumbar discectomy at the same level 8 years prior to presenting with progressive myelopathy secondary to retrograde venous reflux into the perimedullary vein. A 69-year-old man presented with progressive lower extremity weakness and sensory disturbance and loss of sphincter control 8 years after endoscopic lumbar discectomy for a disc herniation at L4-5 level. Magnetic resonance imaging showed spinal cord edema and dilated intradural perimedullary vessels. Spinal angiography revealed an epidural AVF at the site of the previous endoscopic lumbar surgery with intradural perimedullary venous drainage. The fistula was successfully occluded via endovascular transarterial embolization, and the patient had stabilization of his neurological deficits. Lumbar spinal epidural AVFs, especially those associated with iatrogenic trauma, are rare. Endoscopic surgical procedure can occlude the epidural venous plexus and disturb venous drainage, thereby inducing local venous hypertension and leading to epidural AVF with perimedullary venous drainage. This type of pathology should be considered within the differential diagnosis of delayed neurological deterioration after spinal surgery.

Spinal Epidural Arteriovenous Fistulas With Unusual Manifestation of Sudden Onset of Severe Neurological Deficits: Case Report

Spinal epidural arteriovenous fistulas with perimedullary venous drainage cause venous hypertension, and usually manifest as slowly progressive myelopathy. We treated two patients presenting with sudden onset of severe neurological deficits. Moreover, in Case 1, the venous drainage was exclusively epidural and no perimedullary venous drainage was present. Angiographic findings of this patient were characterized by a slow-flow fistula with marked retention of the epidural venous drainage. Rapidly progressing thrombosis of the epidural venous plexus may have caused the sudden onset of the symptoms. In Case 2, hematomyelia may also be possibly associated with the sudden onset of the symptoms. Early diagnosis and treatment are essential to achieve favorable outcome in such cases because venous congestion results in irreversible venous infarction within a short period.