Extradural 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.

A Classification Proposal for Spinal Vascular Lesions.

A Classification Proposal for Spinal Vascular Lesions.

Spinal Vascular Malformations: Treatment and Outcome

Vascular malformations of the spinal cord are a rare and complex clinical entity and can lead to severe morbidity with progressive spinal cord symptoms if not treated properly. In early stages, the disease is characterized by slowly progressive, nonspecific symptoms, such as gait disturbance, paresthesia, diffuse sensory symptoms, and radicular pain; in the late stages, bowel and bladder incontinence, erectile dysfunction, and urinary retention may develop. In recent decades, understanding and treatment of spinal vascular malformations have improved with the evolution of diagnostic tools and treatment modalities; however, it is still difficult to manage these cases because of the complexity of the pathology. The aims of this study were to present the long-term outcomes of our patients and to discuss the optimal management strategies. We reviewed the records of 78 patients with spinal vascular malformations and performed a retrospective, single-center case series evaluating initial occlusion, recanalization, retreatment, and neurologic status of patients with dural arteriovenous fistulas, perimedullary arteriovenous fistulas, arteriovenous malformations, and extradural arteriovenous fistulas who had undergone embolization and/or surgery. No mortality was observed. Complete obliteration was achieved in 76 patients (97.4%). Both endovascular and surgical treatment of spinal vascular malformations resulted in significant long-term recovery from myelopathic symptoms and improvement in quality of life for most patients.

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.

Spinal extradural arteriovenous fistulas with retrograde intradural venous drainage: Diagnostic features in digital subtraction angiography and time-resolved magnetic resonance angiography

Spinal extradural arteriovenous fistulas (AVFs) may be more difficult to prospectively identify than dural AVFs because they are less common than dural AVFs. The primary purpose was to further characterize the diagnostic imaging of spinal extradural AVFs with intradural retrograde venous drainage. The magnetic resonance (MR) imaging and angiographic results of 23 patients with suspected spinal dural AVFs were analyzed in order to distinguish dural and extradural AVFs. The diagnostic accuracy of MR angiography was retrospectively compared between dural and extradural AVFs. All 23 patients showed high intensity in the spinal cord on T2-weighted MR images. Eighteen out of 23 patients were diagnosed with dural AVFs, while the remaining 5 were diagnosed with extradural AVFs by angiography. Extradural AVFs were fed by a branch of the segmental artery to the vertebral body, characterized by a fistula located in the ventral extradural space, and drained retrogradely via an epidural venous pouch into intradural veins. The segmental artery was localized within 1 vertebral level using MRA in 12 out of 18 patients (67%) with dural AVFs and in 1 out of 5 patients (20%) with extradural AVFs (p=0.09). The reasons behind the lower accuracy was mainly the image misinterpretation. Congestion of the spinal cord in spinal extradural AVFs with intradural retrograde venous drainage was similar to that in dural AVFs, whereas its angioarchitecture differed from that of dural AVFs. A clearer understanding of the imaging features of extradural AVFs is important for improving the diagnostic accuracy and clarifying treatment targets.

Minimally invasive approach for the treatment of lumbar epidural arteriovenous fistulas with intradural venous reflux

BackgroundVascular lesions of the spinal cord are increasingly recognized. The most common types of these lesions are dural arteriovenous fistulas (AVFs) whereas, extradural AVFs are a very rare type of spinal AVF and can be associated with either extradural or intradural venous reflux. This results in neurological deficits through congestive or compressive myeloradiculopathy. These lesions must be treated to allow stabilization or improvement of neurologic status, either by endovascular therapy or microsurgical interruption. However, because some patients are not amenable to endovascular treatment, surgery is often warranted, which usually involves hemi- or bilateral laminectomy following a midline approach with bilateral muscle stripping. The main drawback of this procedure is directly related to the morbidity of the approach. Although, minimally invasive approaches are likely to overcome this drawback, there is a lack of reported experience supporting their use for treating spinal dural AVFs. Case presentationTwo patients, aged 62 and 79 years old, presented with rapidly progressive myelopathy characterized by paraparesis and sphincter disturbance. Spinal magnetic resonance imaging showed spinal cord oedema with perimedullary flow voids in both cases. Digital subtraction angiography revealed extradural AVFs associated with perimedullary venous reflux. Endovascular therapy was not feasible. Both patients were treated with microsurgical interruption of the intradural vein through a non-expendable retractor. Complete exclusion was confirmed on postoperative angiography, resulting in resolution of spinal cord edema and improved neurological functional status at 2-year follow-up. ConclusionThe minimally invasive surgical treatment of spinal AVFs with epidural venous reflux is safe and effective. This approach is a valuable alternative to endovascular therapy and the standard open microsurgical approach.

Spinal extradural arteriovenous fistulas

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. 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. 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. 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.

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

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. 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. 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. 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.

Spinal extradural arteriovenous fistulas: a clinical and radiological description of different types and their novel treatment with Onyx

Spinal extradural (epidural) arteriovenous fistulas (AVFs) are uncommon vascular lesions of the spine with arteriovenous shunting located primarily in the epidural venous plexus. Understanding the complex anatomical variations of these uncommon lesions is important for management. The authors describe the different types of spinal extradural AVFs and their endovascular management using Onyx. Eight spinal extradural AVFs in 7 patients were studied using MR imaging, spinal angiography, and dynamic CT (DynaCT) between 2005 and 2009. Special consideration was given to the anatomy, pattern of venous drainage, and mass effect upon the nerve roots, spinal cord, and vertebrae. The neuroaxial location of the 8 spinal extradural AVFs was lumbosacral in 1 patient, lumbar in 4 patients, thoracic in 2 patients, and cervical in 1 patient. Spinal extradural AVFs were divided into 3 types. In Type A spinal extradural AVFs, arteriovenous shunting occurs in the epidural space and these types have an intradural draining vein causing venous hypertension and spinal cord edema with associated myelopathy or cauda equina syndrome. Type B1 malformations are confined to the epidural space with no intradural draining vein, causing compression of the spinal cord and/or nerve roots with myelopathy and/or radiculopathy. Type B2 malformations are also confined to the epidural space with no intradural draining vein and no mass effect, and are asymptomatic. There were 4 Type A spinal extradural AVFs, 3 Type B1s, and 1 Type B2. Onyx was used in all cases for embolization. Follow-up at 6-24 months showed that 4 patients experienced excellent recovery. Three patients with Type A spinal extradural AVFs attained good motor recovery but experienced persistent bladder and/or bowel problems. The current description of the different types of spinal extradural AVFs can help in understanding their pathophysiology and guide management. DynaCT was found to be useful in understanding the complex anatomy of these lesions. Endovascular treatment with Onyx is a good alternative for spinal extradural AVF management.

Extradural arteriovenous fistulas involving the vertebral artery in neurofibromatosis Type 1

Spinal extradural arteriovenous fistulas (AVFs) are rare lesions that may be associated with neurofibromatosis Type 1 (NF1). In these patients, the shunt typically occurs between the V(2) segment of the vertebral artery and the epidural venous plexus. Previously, reported cases have been treated either by using endovascular embolization or, sporadically, by open surgery. In surgical reports, proximal deafferentation or manipulation of the venous portion of the shunt--including suture, resection, or open embolization of the epidural ectasia--was attempted with variable results. The authors report on a case of a young patient with NF1 who underwent emergency surgical disconnection of a cervical extradural AVF after previously unsuccessful endovascular and surgical therapy. The lesion drained into a giant intrathecal varix, causing severe myelopathy. After surgery, the patient recovered almost completely. This experience clarified the surgical anatomy of these malformations and showed that, when surgery is necessary, the optimal treatment providing complete and permanent cure of this condition is direct closure of the epidural shunt pedicle.

Thoracic spine extradural arteriovenous fistula: Case report and review of the literature

Background Spinal extradural arteriovenous fistula is a rare, disabling, but potentially treatable disease. Only 27 cases have been reported so far in the past 40 years. Case Description An 18-year-old adolescent girl developed repeated back pain and mild paraplegia after a training course. Magnetic resonance imaging revealed a vessel-like lesion at the spinal extradural space, compressing the spinal medulla at the T5 level. Angiography disclosed a focal fistula fed by branches of the intercostal artery. The vascular mass was surgically removed and confirmed pathologically. Conclusion Spinal extradural arteriovenous fistulas have an arterial supply that originates outside the spinal dura, with venous draining into the spinal extradural venous plexus. They may lead to myelopathy, radiculopathy, or spontaneous extradural hematoma, due to dilated vein compression, blood stealing, or spinal venous hypertension. Extradural hematoma needs emergency laminectomy and clot evacuation. And extradural arteriovenous fistulas should be treated actively by embolization, surgical resection, or both. Appropriate treatment will stabilize the patient or result in neurological improvement.

Surgical interruption of intradural draining vein as curative treatment of spinal dural arteriovenous fistulas.

To establish if interruption of the intradural draining spinal vein or surgical excision are curative treatments for spinal dural arteriovenous fistulas (AVFs), the medical records and radiographic studies of 19 patients with spinal dural AVFs and progressive myelopathy were reviewed. Spinal arteriograms were obtained before and within 2 weeks after surgery in 19 patients, and after a delay of 4 months or more in 11 patients. The mean clinical and arteriographic follow up was at 37 and 35 months, respectively. In the 11 patients who underwent excision of the dural AVF there was no evidence of a residual lesion upon immediate or delayed postoperative arteriography. Surgery in eight patients consisted of simple interruption of the intradural draining vein as it entered the subarachnoid space. In six of these patients the vein draining the AVF intrathecally provided the only venous drainage of the AVF. In these six patients there was no immediate (six of six) or delayed (four of six) arteriographic evidence of residual or recurrent flow through the AVF. Two patients had an AVF with both intra- and extradural venous drainage; after intradural division of the draining vein there was residual flow through the AVF into the extradural venous system. In one of these two patients intrathecal venous drainage was reestablished, which required additional therapy. In the other patient the extradural AVF spontaneously thrombosed and was not evident on delayed follow-up arteriography. In patients with spinal dural AVFs with only intrathecal medullary venous drainage, which includes most patients with these lesions, surgical interruption of the intradural draining vein provides lasting and curative treatment. In patients with both intra- and extradural drainage of the AVF, complete excision of the fistula or interruption of the intra- and extradural venous drainage of the fistula is indicated. In patients in whom a common vessel supplies the spinal cord and the dural AVF, simple surgical interruption of the vein draining the AVF is the treatment of choice, as it provides lasting obliteration of the fistula and it is the only treatment that does not risk arterial occlusion and cord infarction. Simple interruption of the venous drainage of a spinal dural AVF provides lasting occlusion of the fistula, as it does for cranial dural AVFs, if all pathways of venous drainage are interrupted. This result provides further evidence that the venous approach to the treatment of dural AVFs can be used successfully.