Spinal dural arteriovenous fistulas--an underdiagnosed disease. A review of patients admitted to the spinal unit of a rehabilitation center

Spinal dural arteriovenous fistula: a comprehensive review of the history, classification systems, management, and prognosis

Spinal dural arteriovenous fistulas account for the majority of spinal vascular malformations. They are typically located in the thoracolumbar region and are diagnosed in the middle-aged and elderly populations. Although spinal dural arteriovenous fistulas have been postulated to be acquired, their exact development remains uncertain. Typically, the arteriovenous shunt is situated close to the spinal nerve root, inside the dura mater, where the blood from the radiculomeningeal artery and radicular vein intermix. Throughout history, there have been multiple classification systems of spinal arteriovenous shunts since 1967. Those were mainly based on the evolution of diagnostic studies as well as the treatment of these lesions. Such classification systems have undergone significant changes over the years. Unlike intracranial dural arteriovenous fistula, spinal dural arteriovenous fistula is progressive in nature. The neurological manifestations, due to venous congestion, tend to be insidious as well as non-specific. These include sensory deficits, such as paresthesia, bilateral and/or unilateral radicular pain affecting the lower limbs, and gait disturbances. Spinal dural arteriovenous fistulas can be suspected on magnetic resonance imaging/magnetic resonance angiography and confirmed by digital subtraction angiography (DSA). The management includes surgery, endovascular therapy, and in selected cases, radiotherapy. The treatment goal of spinal dural arteriovenous fistula is to halt the progression of the disease. The prognosis depends on both the duration of symptoms as well as the clinical condition prior to therapy. The present article comprehensively reviews the pathophysiology, changes in classification systems, natural history, clinical manifestations, radiological features, management, and prognosis.

Spinal Osseous Epidural Arteriovenous Fistula with Intradural Reflux: A Case Report

The authors report a rare case of spinal osseous epidural arteriovenous fistula (AVF) with intradural reflux. A 71-year-old lady with a past history of a T12 compression fracture and neurofibromatosis type 1 presented with progressive paraparesis. Magnetic resonance (MR) images of the thoracolumbar spine showed edema of the spinal cord and flow voids. Catheter angiography revealed segmental arteries from T11 to L1 feeding an AVF in the epidural space. The AVF drained not only into the epidural venous plexus but also into the perimedullary veins. Of note, there was an intraosseous drainage route that involved the basivertebral vein of T12. Under the diagnosis of spinal osseous epidural AVF with intradural reflux, surgical interruption of the intradural arterialized draining vein was performed. Spinal osseous epidural AVF with intradural reflux is rare with only four cases reported in the past. We believe that spinal osseous epidural AVF should be recognized as a variant of spinal epidural AVF.

Spinal dural arteriovenous fistula 8 years after lumbar discectomy surgery: A case report and review of literature

BACKGROUND

Spinal dural arteriovenous fistula (SDAVF) is an extremely rare vascular malformation of the central nervous system that is often confused with degenerative spinal disorders due to similar early symptoms and clinical features. Here, we report a case of SDAVF recurrence 8 years after lumbar spine surgery and summarize relevant literature.

CASE SUMMARY

A 54-year-old male was admitted to our hospital complaining of lower back pain, numbness in both lower extremities and intermittent claudication. Subsequent imaging identified lumbar spinal stenosis. Following surgical treatment, the patient’s symptoms significantly resolved, and he was able to perform daily activities. However, similar symptoms appeared 8 years later, followed by confirmation of SDAVF diagnosis. The patient underwent neurosurgery 7 mo after symptom onset. The follow-up period lasted 14 mo, and the patient remains with marginal neurological symptoms.

CONCLUSION

This case highlights the importance of prompt SDAVF diagnosis. Due to its nonspecific clinical presentation, the clinical experience of the surgeon and definitive imaging examination are indispensable. Additionally, timely neurosurgery is effective and may significantly improve patient outcomes.

Acute paraplegia in patient with spinal dural arteriovenous fistula after lumbar puncture and steroid administration: A case report

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Spinal dural arteriovenous fistula is an uncommon cause of longitudinal transverse myelitis.

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Spinal dural arteriovenous fistula can be easily misdiagnosed.

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It usually presents with venous congestive myelopathy symptoms and misdiagnosis is common.

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Prescence of flow voids on MRI should raise the suspicion of underlying fistula.

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Intravenous steroid and lumbar puncture may be associated with acute neurological deterioration.

Introduction and importance

Spinal dural arteriovenous fistula (SDAVF) is an uncommon cause of longitudinal extensive transverse myelitis (LETM). It usually presents with vague congestive myelopathy symptoms and diagnosis is usually difficult on initial presentation. Common daily neurological interventions can aggravate the underlying pathophysiology leading to undesirable acute neurological deterioration. Intravenous steroids administration and lumbar (LP) puncture as a diagnostic tool are amongst the most commonly reported aggravating interventions. This rare case presentation highlights this association with its negative impact on the patient outcome in misdiagnosed cases.

Case presentation

The authors present a sixty-eight-year-old male with paraplegia following steroid administration and LP for presumed inflammatory/autoimmune LETM in the setting of misdiagnosed SDAVF. The absence of flow voids on the conventional T2-weighted magnetic resonance image (MRI) lead to misdiagnosis. He had satisfactory neurological recovery few hours after surgical disconnection.

Clinical discussion

SDAVF is known to cause congestive myelopathy symptoms. Spinal angiogram is the gold standard for diagnosis. Although the exact mechanism is not fully understood, misdiagnosed cases like our case can develop severe neurological deterioration with steroid administration and lumbar puncture.

Conclusion

Although SDAVF is an uncommon cause of LETM, Clinicians should carefully exclude it before proceeding to steroid administration or performing LP as they can lead to devastating neurological deterioration.

Spinal dural arteriovenous fistula presenting as low back pain

Introduction:

Low back pain or numbness of the lower extremities is quite common in the present population. Numerous conditions may cause these symptoms, including spinal vascular anomaly. Identifying and diagnosing the cause of these symptoms are crucial for treatment. Accurate diagnosis based on particular radiological findings in magnetic resonance imaging is crucial for administering adequate therapy to patients, especially in spinal dural arteriovenous fistula.

Case presentation:

We report a case presenting with low back pain and rapid deterioration in paraplegia. Magnetic resonance imaging provided the typical image presentations such as spinal cord edema with tortuous dilated perimedullary venous plexus. The patient was subsequently successfully treated with endovascular embolization.

Discussion:

Spinal dural arteriovenous fistula should be suspected in any patient who presents with myelopathy. Angiography remains the gold standard for confirmation of diagnosis.

Conclusion:

Prompt treatment with endovascular embolization or surgery could improve patients’ outcomes.

Spinal dural arteriovenous fistulas: the most frequent vascular malformations of the spinal cord

Spinal dural arteriovenous fistulas are produced by direct communication between the arterial and venous systems of the spinal cord, causing hypertension in the latter with spinal cord dysfunction. It is a rare pathology with unknown etiology and non-specific clinical symptoms that usually results in a delayed diagnosis. Often radiologists are the first to guide the disease towards an adequate diagnosis. Characteristic findings can be seen through MR or MR angiography, and may even locate the fistula in a high percentage of cases, although the pathology must be confirmed by spinal angiography. There are two treatment modalities: endovascular and surgical therapy. Endovascular treatment has improved in recent years with the advantages of a less invasive approach and is therefore usually chosen as primary therapy. In this article we review the main clinical manifestations, imaging findings and treatment of this pathology.

Surgical treatment for spinal dural arteriovenous fistulas: Outcome, complications and prognostic factors

BACKGROUND AND PURPOSE

Spinal dural arteriovenous fistulas (SDAVFs) are rare, acquired pathology and they inevitably lead to severe disability if untreated. The aim of this study is to present the outcome and complications, and to find factors that may affect the outcome after surgical treatment.

METHODS

Seventeen consecutive patients (men - 14, women - 3, age: 41-79) were retrospectively analyzed. The patients presented with paraparesis (88%), bladder symptoms (71%) and/or sensory disturbances (65%). The fistula was found in the upper thoracic spine in 2 cases, in the lower thoracic (T7-Th12) in 11 cases, and in the lumbar spine in 4 cases. Microsurgical shunt interruption was performed in all, followed by epidural arteries coagulation in 12 cases.

RESULTS

In the long term, improvement or achievement of a good stable condition was observed in 13 patients (76%), and no patient deteriorated. All 5 paraplegic patients improved by at least 1 grade in MCS. Satisfactory results (modified McCormick Scale grades I-II) were found in 10 patients (59%), and 15(88%) were independent. Postoperative complications occurred in 4 patients (24%), two of them (12%) required revision surgery for epidural hematoma. The success rate was 94%; one patient required revision surgery for recurrent SDAVF. Better neurological condition on admission (p=0.0098) and age >60 years (p=0.0498) were the factors associated with satisfactory outcome.

CONCLUSIONS

Microsurgical closing of a SDAVF brings good and stable results over time. Aggressive treatment should be attempted even in cases of total loss of spinal cord function. Neurological condition before surgery and age may influence the outcome.

Late diagnosis of spinal dural arteriovenous fistulas resulting in severe lower-extremity weakness: a case series

BACKGROUND CONTEXT

Spinal dural arteriovenous fistula (SDAVF) is a slow-flow extramedullary vascular lesion affecting primarily the lower thoracic and lumbar spine. The clinical sequela of these vascular changes is progressive myelopathy and severe lower-extremity weakness. Although surgical or embolic treatment of SDAVFs has improved significantly in the last years, the ambiguity of the symptoms may complicate and delay the diagnosis. The influence of the postponed diagnosis on the functional outcome of patients with SDAVF is unknown.

PURPOSE

To describe a case series of patients with SDAVF that illustrates that delayed diagnosis leads to grave neurologic and functional prognosis.

STUDY DESIGN

A case series.

METHODS

We present a series of seven patients, treated in a tertiary university rehabilitation center over 20 years. Clinical, radiologic, and functional outcomes were evaluated by retrospective chart review. Neurologic and functional evaluation at the end of rehabilitation was evaluated with the lower extremities motor score and the Aminoff-Logue scale, respectively.

RESULTS

All our patients were men with a mean age of 60.3±16 years (30-72 years), mean time until the diagnosis of SDAVF was 302.8±239 days (60-730 days), and mean overall length of stay in acute department and rehabilitation unit was 88.6±34 days (46-149 days). At the end of rehabilitation period, four patients remained at wheelchair level with an Aminoff-Logue scale grading of five whereas other functional scales showed also low levels of recovery.

CONCLUSIONS

Our series showed that the potential for functional ambulation was poor despite prolonged rehabilitation treatment in late diagnosis SDAVF. Awareness of the early symptoms of SDAVF and immediate intervention may help reduce impairment in such patients.

Value of prominent flow voids without cord edema in the detection of spinal arteriovenous fistulae

PURPOSE

To determine the prevalence of spinal dural arteriovenous fistulae (SDAVF) in patients presenting with prominent vascular flow voids on imaging without other imaging findings suggestive of SDAVF.

METHODS

We retrospectively identified patients from January 1, 2005 to March 1, 2012 who underwent spinal angiography for suspected SDAVF with prominent vascular flow voids on prior imaging. We excluded patients with other major spinal pathology or other imaging findings of SDAVF including cord hyperintensity, enhancement, or expansion. We calculated the proportion of patients with positive findings for SDAVF on angiography and evaluated the prevalence of SDAVF for this finding alone and in correlation with clinical findings.

RESULTS

18 patients underwent spinal angiography for prominent flow voids on imaging without other spinal pathology or imaging findings of SDAVF. Three had a SDAVF detected on angiography. The prevalence of SDAVF in this population was low, only 17% (95% CI 6-39%). All of the patients with positive angiography findings had myelopathy, increasing the prevalence to 100% if the additional clinical finding of myelopathy was present.

CONCLUSIONS

Prominent flow voids without other imaging findings suggestive of SDAVF is poorly predictive of the presence of a SDAVF, unless myelopathy is present clinically.

Spinal dural arteriovenous fistula presenting with paraplegia following lumbar puncture

Spinal dural arteriovenous fistulas are rare lesions with an annual incidence of 1 per 100,000 population. In patients with this disease, an abnormal vascular dural shunt exists between a dural branch of a segmental artery and a subdural radicular vein that drains the perimedullary venous system, leading to venous hypertension and secondary congestive myelopathy. Generally, patients present with progressive paraparesis, urinary disturbances, and gait ataxia. In this report the authors describe a 61-year-old woman with a spinal dural arteriovenous fistula who developed an acute paraplegia after a nontraumatic lumbar puncture. The possible underlying mechanisms and treatment options are discussed.

Correlation between time to diagnosis and rehabilitation outcomes in patients with spinal dural arteriovenous fistula

BACKGROUND

Spinal dural arteriovenous fistulas (SDAVFs) are the most common spinal vascular malformations and can be a significant cause of myelopathy although they are under diagnosed. Surgical or embolization treatment of SDAVFs improved significantly in the last decade. However, a high percentage of patients are still left with severe disability.

OBJECTIVE

To describe the correlation between time to diagnosis and the rehabilitation outcomes of eight patients with SDAVFs.

DESIGN

Retrospective chart study of all SDAVF patients in 20 years.

SETTING

A tertiary university rehabilitation center.

MAIN OUTCOME MEASURES

The lower extremities motor score (LEMS), Functional Independence Measure (FIM), Spinal Cord Independence Measure (SCIM) and Walking Scale for Spinal Cord Injury (WISC II). Overall prognosis was evaluated using the Aminoff-Logue scale (ALS).

RESULTS

There were seven men and one woman with mean age of 61.3 ± 15 (30-72) and mean time until the diagnosis of SDAVF of 265.5 ± 245 days (4-730). At the end of rehabilitation period, five of the eight patients remained wheelchair dependent. Strong correlation was found between LEMS, FIM, SCIM, and WISC II scores and the functional level according to the ALS scale. A significant correlation was found between time to diagnosis and the height of the SDAVF, the clinical and rehabilitation outcomes. Patients with high SDAVF which were diagnosed late had the poorest prognosis.

CONCLUSIONS

The potential for functional ambulation in patients with SDAVF is related to the time of intervention. This finding emphasizes the important of early diagnosis and early intervention in SDAVF.

The diagnosis of spinal dural arteriovenous fistulas

STUDY DESIGN

Retrospective consecutive case series.

OBJECTIVE

To review and analyze clinical presentations and radiological imaging of 326 consecutive patients with spinal dural arteriovenous fistula (SDAVF) from 2 institutions.

SUMMARY OF BACKGROUND DATA

The clinical presentations of SDAVF are nonspecific. Patients may be initially diagnosed with other spinal diseases. Magnetic resonance imaging (MRI) can reveal spinal cord changes associated with the disorder, but neurosurgeons often overlook these changes.

METHODS

From 1989 to 2009, 326 patients were diagnosed with SDAVF and treated at Qilu Hospital of Shandong University and the Xuanwu Hospital of the Capital University of Medical Sciences. We retrospectively reviewed the clinical records and radiological images of all patients, and collected and analyzed the related data.

RESULTS

Two hundred eighty-two males and 44 females (male/female ratio 6.4:1; mean age, 53.9 yr; SD, 12.1) were included in the study. Fistulas were located at the T7 spinal segment (41, 12.6%), but were more typically found at T5 to L5 (273, 82.5%). The most common initial symptoms were lower extremity weakness (234, 71.8%), sensory disturbance (229, 70.2%), and sphincter disturbance (87, 26.7%). These percentages increased to, 85.6%, 80.8%, and 52.5%, respectively, until patients were properly diagnosed. The mean diagnostic time to SDAVF was 19.9 months (SD, 25.2). Two major changes noted on magnetic resonance images were intramedullary T2-weighted signal hyperintensity (284, 87.1%) and perimedullary dilated vessels (251, 77%). Fistulas were often located outside of the vertebral segments of T2-weighted signal change (P = 0.005). Magnetic resonance angiography and computed tomography angiography of 33 (71.7%) patients revealed perimedullary dilated vessels and precisely located fistulas in 19 (41.3%) patients. Magnetic resonance angiography and computed tomography angiography studies of the perimedullary vessels also led to identification of a second fistula through angiography. Degenerative disc disease and myelitis were the most common misdiagnoses, and the patients were often treated incorrectly.

CONCLUSION

"Worsening" and "symptoms combination" are progression characteristics of SDAVF. Patients should undergo spinal magnetic resonance imaging when they are first suspected to have SDAVF. Magnetic resonance angiography and computed tomography angiography as noninvasive angiography are helpful for diagnosis.

Absence of abnormal vessels in the subarachnoid space on conventional magnetic resonance imaging in patients with spinal dural arteriovenous fistulas

Spinal dural arteriovenous fistula (DAVF) is an uncommon condition that can be difficult to diagnose. This often results in misdiagnosis and treatment delay. Although conventional MRI plays an important role in the initial screening for the disease, the typical MRI findings may be absent. In this article, the authors present a series of 4 cases involving patients with angiographically proven spinal DAVFs who demonstrated cord T2 prolongation on conventional MRI but without abnormal subarachnoid flow voids or enhancement. These cases suggest that spinal DAVF cannot be excluded in symptomatic patients with cord edema based on conventional MRI findings alone. Dynamic Gd-enhanced MR angiography (MRA) was successful in demonstrating abnormal spinal vasculature in all 4 cases. This limited experience provides support for the role of spinal MRA in patients with abnormal cord signal and symptoms suggestive of DAVF even when typical MRI findings of a DAVF are absent.

Angioarchitecture of Spinal Dural Arteriovenous Fistula - Evaluation with 3D Rotational Angiography

Purpose

The complex angioarchitecture of spinal dural arteriovenous fistulas (SDAVFs) sometimes preclude angiographic analyses or superselective procedures. Therefore, the effectiveness of 3 dimensional rotational angiography (3DRA) as a detailed imaging technique for SDAVFs was evaluated.

Materials and Methods

Of 57 patients with spinal vascular malformations, recent 13 SDAVF patients underwent 3DRA. The advantage of 3DRA compared to digital subtraction angiography (DSA) in imaging SDAVF was assessed. Angioarchitecture of SDAVF was focused on location, number, and course of feeders and draining vein. Appropriate angled views were also selected to reveal the segmental artery and feeders.

Results

3DRA technique provided additional information for imaging evaluation of SDAVFs compared to DSA; the presence of multiple feeders, including their transdural portions, as well as their courses. The contralaterally angled anterior-oblique-caudal (spider) view showed the radicular feeder by separating the intercostal artery and the dorsal muscular branch. The bottom-to-up (tunnel) view was useful for revealing the location (ventral vs. dorsal) including sharp medial turn of the dural feeder. The dual mode, which displays both vessels and bones, revealed the course of the feeders and the fistula related to the spinal bony column.

Conclusion

Because spinal vasculature overlaps in DSA, 3DRA revealed additional information for evaluations of the number and transdural course of fistular feeders in SDAVFs, and it offers working angles to obtain appropriate views.

Long-term outcome in the repair of spinal cord perimedullary arteriovenous fistulas

BACKGROUND AND PURPOSE

The natural history of PMAVFs, also known as type IV spinal cord AVFs, is incompletely understood. Both open surgical and endovascular approaches have been described as treatment modalities for this disease. The goal of this study was to evaluate the long-term outcome of patients with PMAVFs treated at a single tertiary care institution.

MATERIALS AND METHODS

We conducted a retrospective study of 32 patients with PMAVFs, evaluated between 1983 and 2009. Data were gathered by reviewing outpatient clinic notes, operative and radiologic reports, and spinal angiograms. The PMAVFs were categorized into 1 of 3 types based on the angiographic imaging criteria. Pretreatment and posttreatment ambulation and micturition symptoms were quantified by using the ALS.

RESULTS

Thirty patients underwent corrective procedures, 4 by embolization alone, 11 by surgery alone, and 15 with a combination of the 2. Twenty-eight patients underwent follow-up spinal angiography, with residual shunt noted in 6 patients. The mean follow-up period was 54 months (range, 1-228 months). Analysis of the ALS scores revealed that treatment of PMAVFs, independent of technique, resulted in significant improvement in ambulation but inconsistent changes in micturition. In addition, residual fistula at the time of the follow-up angiogram was associated with worsened neurologic status or lack of improvement. Outcome analysis based on fistula type showed dramatic improvement in ALS ambulation scores (62%) for type 3 fistulas, compared with types 1 and 2 (26% and 27%, respectively).

CONCLUSIONS

Significant improvement in ambulation but in not micturition was observed following treatment. Residual fistula on follow-up angiography was associated with progressive worsening or lack of improvement in neurologic function. Patients with type 3 fistulas were shown to benefit most from treatment, with marked improvement in posttreatment ambulation scores. As endovascular and surgical techniques continue to evolve, further studies are warranted.

Percutaneous intravertebral body embolization of a traumatic spinal epidural arteriovenous fistula with secondary perimedullary venous reflux. A case report

SUMMARY

Arteriovenous fistulas following vertebral fractures are probably very rare. We present a case with fistulous connection between arteries and veins within the fractured 12th thoracic vertebral body with retrograde venous drainage to perimedullary veins resulting in spinal venous hypertension and a cauda equina like symptomatology. Pre-treatment 3D CT enabled us to puncture the venous pouch within the vertebra and deposit glue in the vertebral fistula. The procedure led to a complete occlusion of the fistula and relief of pain and neurological symptoms.

Multiple spinal dural arteriovenous fistulae and deterioration post lumbar puncture

We report a 73-year-old man presenting with bilateral leg numbness and weakness. Three spinal dural arteriovenous fistulae (SDAVF) were found after clinical deterioration post lumbar puncture (LP). This patient highlights the difficulties in the diagnosis and management of SDAVF, and the risks of LP.

Spinal dural arteriovenous fistulas

Spinal dural arteriovenous (AV) fistulas are the most commonly encountered vascular malformation of the spinal cord and a treatable cause for progressive para- or tetraplegia. They most commonly affect elderly men and are classically found in the thoracolumbar region. The AV shunt is located inside the dura mater close to the spinal nerve root where the arterial blood from a radiculomeningeal artery enters a radicular vein. The increase in spinal venous pressure leads to decreased drainage of normal spinal veins, venous congestion, and the clinical findings of progressive myelopathy. On MR imaging, the combination of cord edema, perimedullary dilated vessels, and cord enhancement is characteristic. Therapy has to be aimed at occluding the shunting zone, either by superselective embolization with a liquid embolic agent or by a neurosurgical approach. Following occlusion of the fistula, the progression of the disease can be stopped and improvement of symptoms is typically observed.

Overview of the current role of endovascular and surgical treatment in spinal dural arteriovenous fistulas

Dural arteriovenous fistulas are the most common vascular malformations of the spinal cord. These benign vascular lesions are considered straightforward targets of surgical treatment and possibly endovascular embolization, but the outcome in these cases depends mainly on the extent of clinical dysfunction at the time of the diagnosis. A timely diagnosis is an equally important factor, with early treatment regardless of the type more likely to yield significant improvements in neurological functioning. The outcomes after surgical and endovascular treatment are similar if complete obliteration of the fistulous site is obtained. In the present study, the authors evaluated the current role of each modality in the management of these interesting lesions.

Endovascular and surgical treatment of spinal dural arteriovenous fistulas

INTRODUCTION

The aim of this retrospective study was to evaluate the clinical outcome of patients with spinal dural arteriovenous fistulas (SDAVFs) that were treated with surgery, catheter embolization, or surgery after incomplete embolization.

METHODS

The study included 21 consecutive patients with SDAVFs of the thoracic, lumbar, or sacral spine who were treated in our institution from 1994 to 2007. Thirteen patients were treated with catheter embolization alone. Four patients underwent hemilaminectomy and intradural interruption of the fistula. Four patients were treated by endovascular techniques followed by surgery. The clinical outcome was assessed using the modified Aminoff-Logue scale (ALS) for myelopathy and the modified Rankin scale (MRS) for general quality of life. Patient age ranged from 44 to 77 years (mean 64.7 years).

RESULTS

Surgical as well as endovascular treatment resulted in a significant improvement in ALS (-62.5% and -31.4%, respectively, p < 0.05) and a tendency toward improved MRS (-50% and -32%, respectively) scores. Patients that underwent surgery after endovascular treatment due to incomplete occlusion of the fistula showed only a tendency for improvement in the ALS score (-16.7%), whereas the MRS score was not affected.

CONCLUSION

We conclude that both endovascular and surgical treatment of SDAVFs resulted in a good and lasting clinical outcome in the majority of cases. In specific situations, when a secondary neurosurgical approach was required after endovascular treatment to achieve complete occlusion of the SDAVF, the clinical outcome was rather poor. The best first line treatment modality for each individual patient should be determined by an interdisciplinary team.