Endovascular treatment of high-flow cervical direct vertebro-vertebral arteriovenous fistula with detachable coils and Onyx liquid embolic agent

Vertebro-Vertebral Arteriovenous Fistulae: A Case Series of Endovascular Management at a Single Center

OBJECTIVE

Vertebro-vertebral arteriovenous fistulae (VVFs) are a rare disorder characterized by a direct shunt between the extracranial vertebral artery and the veins of the vertebral venous plexus. This study aims to comprehensively review the characteristics and outcomes of endovascular treatments for VVFs at our center.

METHODS

A retrospective review was conducted on 14 patients diagnosed with a VVF who underwent endovascular treatment at Siriraj Hospital from January 2000 to January 2023. The study assessed patient demographics, presentation, fistula location, treatment strategies, endovascular techniques employed, and treatment outcomes.

RESULTS

Among the 14 patients, 11 (78.6%) were female, with an age range from 25 to 79 years (median: 50 years). Spontaneous VVFs were observed in 64.3% of the cases, including three associated with neurofibromatosis type 1 (NF-1). Iatrogenic injury accounted for two cases, and three patients had VVFs resulting from traffic accidents. A pulsatile neck mass and tinnitus, with or without neurological deficits, were common presenting symptoms. Active bleeding was observed in three cases with vascular injury, while unilateral proptosis, congestive heart failure, and incidental findings each presented in one patient. All the VVFs were successfully obliterated without major treatment complications. Parent vessel sacrifice was performed in 85.7% of the cases, while vertebral artery preservation was achieved in the remaining two patients. Embolic materials included detachable balloons, detachable coils, and n-butyl cyanoacrylate (NBCA) glue. All the presenting symptoms showed improvement, and no morbidity or mortality was observed.

CONCLUSIONS

Endovascular embolization is a feasible and effective approach for achieving complete VVF obliteration with safety. Parent artery sacrifice should not be reluctantly performed, particularly when adequate collateral circulation is demonstrated.

Cervical Extradural Arteriovenous Fistula without Intradural Drainage Successfully Treated with Endovascular Treatment Using Both Transvenous and Transarterial Approach: Case Report and Review of Literatures

The classification of spinal extradural arteriovenous fistulas (AVFs) was reported based on a case series treated by microsurgery in 2009 and endovascular interventions in 2011. The present report describes a patient with extradural AVFs at the cervical spine manifesting gradual progressive radiculomyelopathy of bilateral upper extremities. Magnetic resonance imaging (MRI) revealed a mass sign from C1 to C4 at the right ventral side and the spinal cord was deviated to the left and indicated as a flow void sign. Diagnostic angiography revealed an extradural AVFs located at the C1-C4 level that was supplied by bilateral radicular artery from the vertebral artery (VA) and right ascending cervical artery (ACA). The shunting points were recognized multiply at C2/3 and C3/4 levels on the right. The transvenous embolization to the enlarged extradural venous plexus around the shunting points via right hypoglossal canal and the transarterial embolization against multi-feeders of the branch of left radicular artery, right ACA achieved complete occlusion of the lesions. His symptom was gradually recovered, and angiography performed 2 weeks after embolization showed no recurrence. When the arteriovenous shunts in the upper cervical spine were high flow shunts, transvenous approach via the hypoglossal canal might be one option for the treatment of spinal extradural AVFs.

Natural History and Clinical Outcomes of Paravertebral Arteriovenous Shunts

BACKGROUND AND PURPOSE

Paravertebral arteriovenous shunts (PVAVSs) are rare. Whether the intradural venous system is involved in drainage may lead to differences in clinical characteristics through specific pathophysiological mechanisms. This study aims to comprehensively evaluate the natural history and clinical outcomes of PVAVSs with or without intradural drainage.

METHODS

Sixty-four consecutive patients with PVAVSs from 2 institutes were retrospectively reviewed. Lesions were classified as type A (n=28) if the intradural veins were involved in drainage; otherwise, they were classified as type B (n=36). The clinical course from initial presentation to the last follow-up was analyzed.

RESULTS

The patients with type A shunts were older at presentation (52.5 versus 35.5 years, P<0.0001) and more likely to have lower spinal segments affected than patients with type B PVAVSs (67.8% versus 13.9%, P=0.00006). After presentation, the deterioration rates related to gait and sphincter dysfunction were significantly higher in patients with type A than type B shunts (gait dysfunction: 71.8%/y versus 17.0%/y, P=0.0006; sphincter dysfunction: 63.7%/y versus 11.3%/y, P=0.0002). According to the angiogram at the end of the latest treatment, 79% of type A and 75% of type B PVAVSs were completely obliterated. If the lesions were partially obliterated, a significantly higher clinical deterioration rate was observed in patients with type A shunts than those with type B shunts (69.9%/y versus 3.2%/y, P=0.0253).

CONCLUSIONS

Type A PVAVSs feature rapid progressive neurological deficits; therefore, early clinical intervention is necessary. For complex lesions that cannot be completely obliterated, surgical disconnection of all refluxed radicular veins is suggested.

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

BACKGROUND

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.

OBJECTIVE

To compare demographic, clinical, anatomic, and imaging findings of SDAVFs and SEDAVFs.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Clinical features and treatment strategy of paraspinal arteriovenous shunt (PAVS): a systematic review with individual participants data meta-analysis

BACKGROUND

Because of the rarity of the disease, paraspinal arteriovenous shunt (PAVS) is not well recognized, and therapeutic options remain controversial. To introduce a rare disease of PAVS and demonstrate its etiology, clinical features, treatment options, and outcomes, we presented a case report and conducted a systematic review and individual participants data (IPD) meta-analysis.

METHODS

Studies regarding on PAVS were integrated and IPD were obtained including patients' demographics, disease etiology, clinical and radiologic features, clinical courses and outcomes. Clinical manifestation and treatment outcomes were reviewed, and comparison analysis (cervical versus thoracolumbar) were performed. Further, logistic regression analyses were conducted to identify the poor prognostic factors (incomplete obliteration).

RESULTS

Fifty-two articles were selected, and 88 patients enrolled. General and location-specific characteristics of PAVSs were identified: '3/4 of the isolated and 1/4 of the associated etiology', 'bruit, thrill, or murmur (cervical) and weakness (thoracolumbar) as common symptoms', '40% multiple feeders', and '22% intradural venous involvement'. Endovascular treatment was usually preferred (75%). Of 88 enrolled patients, 18 patients showed incomplete obliteration (20.5%). In multivariate analysis, 'etiologies of systematic genetic dysplasia (P = 0.031) and trauma (negatively, 0.038)' were significantly associated with incomplete obliteration. The parameters of 'multiple feeders (0.066)' and 'combined approach (negatively, 0.065)' are verified only in univariate analysis.

CONCLUSION

General as well as location-specific characteristics of PAVS is successfully demonstrated. Approximately 20% of the incomplete obliteration is noted, and three potential poor prognostic factors are identified, namely, 'etiology of systematic genetic dysplasia (positive) and trauma (negative)', 'combined approach (negative), and 'multiple feeders'.

Direct Vertebral Artery Puncture During Open Surgery for the Endovascular Treatment of a Recurrent Vertebro-Vertebral Arteriovenous Fistula

BACKGROUND

Vertebro-vertebral arteriovenous fistula (VVAVF) is a condition in which there is an arteriovenous shunt directly connecting the extracranial vertebral artery to the vertebral venous plexus. Many reports have described fistula occlusion or vertebral artery trapping as treatments for VVAVF. Here, we describe a case in which endovascular treatment for recurrent VVAVF using a transfemoral approach was unsuccessful; thus, the vertebral artery (VA) was directly punctured during open surgery and the treatment was successful.

CASE DESCRIPTION

The patient was a 47-year-old female who had undergone endovascular treatment for VVAVF. The patient developed subarachnoid hemorrhage. Digital subtraction angiography revealed a left VVAVF. The left VA was trapped with coils at the C2 and C3 levels and an arteriovenous shunt formed from the VA between the 2-coil mass to the vertebral venous plexus. In addition, reflux was observed in the spinal vein. Endovascular treatment was attempted with a transfemoral approach, but we could not reach the shunt. Five days post-treatment, the patient had a second subarachnoid hemorrhage and surgery was performed to occlude the radiculomedullary vein; however, residual reflux went into the spinal vein from another spinal level. Later, the VA was directly punctured and treated with N-butyl cyanoacrylate, and the shunt disappeared.

CONCLUSIONS

Direct puncture of the vertebral artery was useful in this case, where it was difficult to reach the lesion. Although direct VA puncture is associated with more complications than the transfemoral or transbrachial approach, it may be an option when other methods are difficult.

Revisiting the Vertebral Venous Plexus-A Comprehensive Review of the Literature

The venous drainage of the vertebral and paravertebral regions is important for a better understanding of hematogenous disease spread. Moreover, the spine surgeon must be well acquainted with this anatomy to minimize intraoperative and postoperative complications. A comprehensive review of the vertebral venous plexus (Batson plexus) was performed with a concentration on the clinical and surgical correlations of this venous network.

Cervical spinal extradural arteriovenous fistula successfully treated using transarterial balloon-assisted coil embolization

We present the case of a patient who developed compressive radiculopathy that was found to be associated with a spinal extradural arteriovenous fistula. The fistula was successfully obliterated with transarteiral balloon-assisted coiling, after which the patient was symptom-free. Although spinal extradural arteriovenous fistula is rare, this pathology should be considered in the differential diagnosis of spinal radiculopathy or myelopathy. Endovascular treatment appears to have been successful in resolving the symptoms associated with this pathology.

Massive Intramedullary Hemorrhage After Subarachnoid Hemorrhage in Patient with Vertebrovertebral Arteriovenous Fistula

BACKGROUND

Hemorrhagic presentations are rare in vertebrovertebral arteriovenous fistula (VVAVF). To the best of our knowledge, this is the first report of a patient initially presenting with subarachnoid hemorrhage and progressing to intramedullary hemorrhage.

CASE DESCRIPTION

The authors report on a 59-year-old man with VVAVF who developed massive intramedullary hemorrhage. Twelve months before ictus, the patient presented with subarachnoid hemorrhage. Although we recommended endovascular surgery, the patient refused treatment. Twelve months after the initial attack, the massive intramedullary hemorrhage in cervical spinal cord caused complete spinal cord injury. Emergent endovascular intervention was performed after the intramedullary hemorrhage, but there was no neurologic improvement.

CONCLUSIONS

Identification of this phenomenon is important in VVAVF because intramedullary hemorrhage dramatically degrades patient outcome. Prompt surgical intervention is mandatory for VVAVF cases presenting with subarachnoid hemorrhage.

Vertebral Arteriovenous Fistula: A Review Article

OBJECTIVE

Vertebrovertebral fistulas (VVFs) are uncommon lesions that can arise spontaneously or secondarily to iatrogenic or mechanical trauma. We performed a systematic review of the literature to obtain information regarding demographics, clinical presentation, treatment modalities, outcome, and complications associated with treatment.

METHODS

A literature search was performed by a reference librarian and after screening, 128 case reports and 16 case series were left for inclusion in the review. All possible data were abstracted by 3 authors, results were tabulated, and descriptive statistics (mean, range, and proportions) were reported. No formal statistical analysis was performed as part of this study.

RESULTS

A total of 280 patients were analyzed. VVFs can be categorized in 3 subgroups (iatrogenic, spontaneous, and traumatic), based on the mechanism of formation, and these different causes share different underlying demographics that bear important treatment considerations. Traumatic VVFs are more commonly seen in young men; the spontaneous form is more commonly seen in young women. Iatrogenic VVFs are more commonly seen in elderly people. Spontaneous VVFs are most commonly located between C1 and C2. Most iatrogenic (n = 39; 57%), spontaneous (n = 106; 82%), and traumatic (n = 53; 73%) VVFs were treated with deconstructive (defined as occlusion of fistula and feeding vessels) endovascular therapy. Overall treatment-related permanent morbidity was 3.3% (9/270) and mortality was 1.5% (4/270).

CONCLUSIONS

VVFs are uncommon lesions, and treatment is often indicated, even in patients without retrograde venous drainage. When treatment is undertaken, the cause of presentation and associated patient demographics should be considered when planning the treatment strategy.

Spontaneous regression of an idiopathic arteriovenous fistula of the right vertebral artery

A previously healthy 53-year-old male presented with a 2-month history of pulsatile tinnitus, worsening headaches, and neck pain. Given the clinical symptoms, a workup was initiated to assess for a vascular etiology such as a dural arteriovenous fistula.

Endovascular treatment of spinal arteriovenous malformations

Spinal arteriovenous malformations (AVMs) are a rare but treatable cause of myelopathy and spinal cord hemorrhage. The clinical presentation and ideal treatment of these lesions vary widely, primarily due to differences in anatomic and angioarchitectural features. Six well-defined types of fistula have been defined: (1) intradural dorsal AVM; (2) intramedullary AVM; (3) extradural-intradural AVM; (4) intradural ventral AVF; (5) extradural/epidural AVF; and (6) conus medullaris AVM. Each of these lesions have unique clinical presentations and variable natural histories and endovascular treatment options. The principles of endovascular treatment include: (1) a complete understanding of the angioarchitecture and anatomic features of the lesion, including identification of radiculomedullary arteries; (2) careful spinal angiography; (3) identification of treatment goals prior to the procedure (i.e., complete occlusion versus partial occlusion aimed at altering natural history); (4) selection of proper embolic agent; and (5) careful follow-up in both the immediate postoperative setting and long term.

Endovascular management of congenital arteriovenous fistulae in the neck

PURPOSE

The purpose of this study was to evaluate congenital arteriovenous fistulae in the neck, including vertebrovertebral and carotico-jugular arteriovenous fistula, with their endovascular management.

MATERIALS AND METHODS

Six patients with congenital arteriovenous fistulae in the neck who underwent endovascular treatment between March 2001 and December 2013 at the Department of Radiology, Ege University School of Medicine were enrolled into this retrospective study. There were four men and two women, with a mean age of 8.6 (range 4-17)years. Patients' demographics and symptoms were noted. Diagnostic computed tomography and/or magnetic resonance angiography were available in all patients. Parent artery and vein of the arteriovenous fistula, location of the fistula, the other features of fistula, endovascular occlusion site, number and type of endovascular materials, and length of follow-up were reviewed.

RESULTS

Four patients had vertebrovertebral fistula, while two patients had carotido-jugular fistula (fistula between maxillary artery and external jugular vein). Four patients underwent detachable balloon occlusion together with coil embolization, while two patients underwent detachable balloon occlusion only. The parent artery was occluded in five patients without clinical consequences, and the remaining fistula was occluded with preservation of the parent artery. The patients did not have any complication in the follow-up period (mean follow-up, 9months).

CONCLUSION

Congenital arteriovenous fistulae in the neck are extremely rare. Endovascular fistula occlusion with parent vessel sacrifice appears to be a safe and minimally invasive treatment option with good results during the follow-up period.

Spinal epidural arteriovenous fistulas

Spinal epidural arteriovenous fistulas (SEDAVFs) are rare complex lesions often presenting with protean clinical manifestations secondary to compressive symptoms or congestive myelopathy. The imaging manifestations of SEDAVFs on MR angiography/MRI include high T2 signal in the spinal cord, vascular engorgement of the epidural space, and prominent intradural vascular flow voids. Given the complexity of these lesions, they are best characterized anatomically on catheter angiography where careful inspection of arterial feeders and venous drainage patterns can be performed. The imaging hallmark of an SEDAVF on angiography is the presence of a dilated epidural venous pouch through which spinal and paraspinal veins are secondarily opacified. In the lower thoracic and lumbar spine, SEDAVFs are usually located in the ventral epidural space and fed mainly by the anteriorly coursing epidural arteries. In the cervical and upper thoracic spine, SEDAVFs and their feeding arteries are more typically located laterally in the spinal canal. Current treatment options include transarterial or transvenous endovascular embolization with liquid embolic agents or coils, and surgical resection/disconnection of the fistula. Further research is needed to better characterize how and why these lesions form and to identify the best treatment modalities.

Endovascular treatment of symptomatic high-flow vertebral arteriovenous fistula as a complication after c1 screw insertion

High-flow vertebral arteriovenous fistulas (VAVF) are rare complications of cervical spine surgery and characterized by iatrogenic direct-communication of the extracranial vertebral artery (VA) to the surrounding venous plexuses. The authors describe two patients with VAVF presenting with ischemic presentation after C1 pedicle screw insertion for a treatment of C2 fracture and nontraumatic atlatoaxial subluxation. The first patient presented with drowsy consciousness with blurred vision. The diffusion MRI showed an acute infarction on bilateral cerebellum and occipital lobes. The second patient presented with pulsatile tinnitus, dysarthria and a subjective weakness and numbness of extremities. In both cases, digital subtraction angiography demonstrated high-flow direct VAVFs adjacent to C1 screws. The VAVF of the second case occurred near the left posterior inferior cerebellar artery originated from the persistent first intersegmental artery of the left VA. Both cases were successfully treated by complete occlusion of the fistulous portion and the involved segment of the left VA using endovascular coil embolization. The authors reviewed the VAVFs after the upper-cervical spine surgery including C1 screw insertion and the feasibility with the attention notes of its endovascular treatment.

Venous drainage of the spine and spinal cord: a comprehensive review of its history, embryology, anatomy, physiology, and pathology

Venous drainage of the spine and spinal cord is accomplished through a complex network of venous structures compartmentalized to intrinsic, extrinsic, and extradural systems. As the literature on this topic is scarce, the following review was performed to summarize the available literature into a single coherent format. The medical literature on the spinal venous system was reviewed using online sources as well as historical documents that were not available online in regard to history, embryology, anatomy, and physiology with a particular emphasis on the pathology affecting this system. The spinal venous system is complex and variable. Proper understanding of all aspects is critical for the management of the pathology that results from its failure.

Spinal extradural arteriovenous fistulas

Object

Our understanding of spinal extradural arteriovenous fistulas (eAVFs) is relatively limited. In this study the authors aimed to provide the demographics, natural history, and treatment results of these rare lesions.

Methods

The authors performed a pooled analysis of data in the PubMed database through December 2012. Individualized patient data were extracted to elucidate demographic, clinical, and angioarchitectural features of spinal eAVFs as well as outcomes following different treatment strategies.

Results

Information on 101 patients was extracted from 63 eligible studies. The mean patient age was 45.9 years, and there was no significant overall sex predilection. Only 3% of the lesions were incidental, whereas 10% occurred in patients who had presented with hemorrhage. None of the 64 patients with at least 1 month of untreated follow-up sustained a hemorrhage over a total of 83.8 patient-years. Patients with lumbosacral eAVFs were significantly older (mean age 58.7 years, p < 0.0001), were significantly more often male (70% male, p = 0.02), had significantly worse presenting Aminoff-Logue motor and bladder scores (p = 0.0008 and < 0.0001, respectively), and had the greatest prevalence of lesions with intradural venous drainage (62% of cases, p < 0.0001). Neurofibromatosis Type 1 (30% of cases, p < 0.0001) and subarachnoid hemorrhage (9% of cases, p = 0.06) were associated with and exclusively found in patients with cervical eAVFs. The overall complete obliteration rate was 91%. After a mean follow-up of 1.7 years, the clinical condition was improved in 89% of patients, the same in 9%, and worse in 2%. Obliteration rates and outcome at follow-up did not significantly differ between surgical and endovascular treatment modalities.

Conclusions

Spinal eAVFs are rare lesions with a low risk of hemorrhage; they cause neurological morbidity as a result of mass effect and/or venous hypertension. Their treatment is associated with a high rate of complete obliteration and improvement in preoperative symptoms.

Risk factors for dural arteriovenous fistula intracranial hemorrhage

To our knowledge, the risk factors for intracranial hemorrhage from dural arteriovenous fistula (DAVF) have not been systematically described, due to the complexity of their anatomy and low incidence. We performed this retrospective study to investigate the DAVF factors predicting intracranial hemorrhage. A 10year database of 144 consecutive patients with DAVF was reviewed. Data collected and analyzed were demographics, morphologic features of DAVF, sex, age, fistula flow rate, arterial supply, lesion location, and venous drainage pattern. Linear univariate and multivariate logistic regression analyses were used to evaluate the association between influencing factors and hemorrhage. A first linear univariate analysis was performed for all influencing factors, and showed that sex, lesion location, and venous drainage pattern were statistically significant in predicting intracranial hemorrhage (p<0.05). Secondary multivariate logistic regression analysis with sex, lesion location, and venous drainage pattern showed that only venous drainage pattern was statistically significant in predicting intracranial hemorrhage (p<0.05). Therefore, venous drainage pattern, particularly the cortical venous drainage, significantly predicts intracranial hemorrhage from DAVF. Both sex and lesion location may be confounding factors in predicting intracranial hemorrhage from DAVF, while the other factors may not be associated with hemorrhage.

Endovascular treatment of vertebro-vertebral arteriovenous fistula. A report of three cases and literature review

This report describes endovascular approaches for occlusion of vertebro-vertebral arteriovenous fistula (VV-AVF) in a series of three cases and a review of the literature. Complete neuroimaging assessment, including CT, MR and DSA was performed in three patients (two female, one male) with VV-AVF. Based on DSA findings, the VV-AVF were occluded by endovascular positioning of detachable balloons (case 1), coils (case 2), or a combination of both (case 3) with parent artery patency in two out of three cases. In this small series, endovascular techniques for occlusion of VV-AVF were safe and effective methods of treatment. To date, there are no guidelines on the best treatment for VV-AVF. Detachable balloons, endovascular coiling, combined embolization procedures could all be considered well-tolerated treatments.

Multimodal endovascular treatment of a vertebrovertebral fistula presenting with subarachnoid hemorrhage and hydrocephalus

Vertebrovertebral fistulae are rare vascular malformations that uncommonly can rupture to present clinically as intracranial subarachnoid hemorrhage. We report a 69-year-old man presenting following spontaneous apoplectic collapse. Initial workup revealed diffuse, intracranial subarachnoid hemorrhage, intraventricular hemorrhage and hydrocephalus. However, the etiology was not apparent on CT angiography of the head. Catheter-based angiography was performed, demonstrating a single-hole, high-flow vertebrovertebral fistula, arising from the V2 segment and decompressing into both cervical and skull base venous structures. Definitive treatment consisted of endovascular fistula obliteration with a combination of coil and liquid embolic material. The patient made a full neurological recovery. High cervical and skull base fistulae are rare causes of intracranial hemorrhage; endovascular treatment is effective at disconnection of the arteriovenous shunt.

WITHDRAWN: Onyx embolization of high flow spontaneous cervical vertebral arteriovenous fistula

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Onyx embolization of high-flow spontaneous cervical vertebral arteriovenous fistula

BACKGROUND AND IMPORTANCE

High-flow spontaneous vertebral arteriovenous shunts in patients with fibromuscular disease (FMD) are rare. Onyx embolization of the recipient veins with shunt disconnection and preservation of the affected vertebral artery in a patient with FMD has not been reported.

CLINICAL PRESENTATION

A 59-year-old female presented with progressive dizziness, pre-syncopal episodes, and tinnitus. Catheter-based angiography identified features of fibromuscular dysplasia and a high-flow right cervical vertebral artery arteriovenous shunt. Onyx embolization of the principle draining veins was performed with initial detachable coil placement. Complete disconnection of the shunt was achieved without sacrifice of the parent vertebral artery.

CONCLUSION

Spontaneous high-flow vertebral arteriovenous shunts can be successfully occluded with Onyx/detachable coil embolization of the principle recipient veins.

Comparative analysis of spinal extradural arteriovenous fistulas with or without intradural venous drainage: a systematic literature review

Object

Spinal arteriovenous malformations (AVMs) are classified into types according to anatomical characteristics: dural arteriovenous fistulas (AVFs), intramedullary AVMs, perimedullary AVFs, and extradural AVFs. Spinal extradural AVFs are much rarer than other types of spinal AVMs, and the available literature on this clinical entity has been based only on case reports or small case series. To investigate the clinical characteristics of patients with spinal extradural AVFs, the authors systematically reviewed the associated literature in the MRI era.

Methods

The PubMed database was searched for all relevant English-language case reports and case series published from 1990 to 2011. The clinical differences between Type A with and Type B without intradural venous drainage were statistically compared, especially regarding clinical features and angiographic and MRI findings.

Results

Forty-five cases of spinal extradural AVFs were found. Type A spinal extradural AVFs were diagnosed in patients with a significantly older age (mean 63.5 years) as compared with Type B AVFs (mean 34.3 years, p < 0.0001). Most cases of Type A spinal extradural AVFs exhibited a diffuse high signal intensity of the spinal cord on T2-weighted MR images and no mass effect (p < 0.0001), and they commonly occurred in the thoracolumbar and lumbar regions (p < 0.0001). On the other hand, cases of Type B lesions exhibited a normal signal intensity of the cord with severe mass effect due to an enlarged extradural venous plexus, and they commonly occurred in the cervical and upper thoracic regions (p < 0.0001), frequently in patients with neurofibromatosis Type 1 (p = 0.049). Because Type B AVFs consisted of high-flow, multiple complex anastomoses between arteries and the epidural venous plexus, patients with these lesions tended to undergo multisession treatments, and the rate of partial AVF occlusion was significantly higher than for Type A AVFs (p = 0.018), although there was no difference in symptom outcomes between the 2 groups.

Conclusions

To the best of the authors' knowledge, a comparative analysis of the clinical differences in patients with extradural AVFs with or without intradural venous drainage has yet to be described in the literature. They concluded that in the diagnosis of spinal extradural AVF, evaluation of intradural venous drainage is important because the cause of myelopathy determines the treatment goals.