Dural Arteriovenous Fistula

Dural arteriovenous fistulas are rare cerebrovascular lesions arising from abnormal connections between an artery and a vein. Though rare, high-grade aggressive lesions can cause hemorrhagic events and non-hemorrhagic neurologic deficits if left untreated. Treatment options vary based on angioarchitecture, location, and patient characteristics and range from conservative observation to palliative treatment, radiosurgery, endovascular embolization, and open surgery. The main goal of treatment is to obliterate flow through the abnormal connection and prevent further arterial flow to the venous system.

Long-term risk of hemorrhage and mortality after treatment of high-grade intracranial dural arteriovenous fistulas

BACKGROUND

Despite recent multi-institutional efforts, long-term data on clinical and radiological outcomes after treatment of high-grade dural arteriovenous fistulas (dAVFs) remain scarce. This study aimed to evaluate the long-term risk of hemorrhage and fistula-related mortality after treatment.

METHODS

Retrospective analysis of all consecutive patients primarily diagnosed with a high-grade dAVF (Cognard grade 2b, 2a+b, 3, 4) between January 2012 and September 2022 at a large neurovascular center. Primary endpoints were intracranial hemorrhage (ICH) and all-cause mortality after treatment; secondary endpoints were angiographic occlusion, complication rate and neurological deficits.

RESULTS

A total of 121 patients underwent 141 treatments (122 endovascular therapy (EVT), 5 radiotherapy, 14 surgery) of which 12 patients (10%) underwent retreatment. Follow-up was available in all patients for a median of 4.2 (IQR 2.5 to 6.6) years. Eleven patients (9%) died during the follow-up period, of which three deaths (2%) occurred after hemorrhagic presentation, one of them attributable to treatment. One death (0.8%) was due to delayed hemorrhage after partial occlusion from EVT. No other post-treatment bleedings occurred. Angiographic follow-up after multimodality treatment was available in 93% of patients after a median of 6 months; the overall occlusion rate was 90%. The overall rate of complications was 25% after EVT and 14% after surgery. The rates of new transient and permanent neurological deficits after EVT were 9% and 3%, respectively.

CONCLUSIONS

The long-term rate of re-bleeding or dAVF-related mortality was low when high rates of angiographic occlusion were achieved. The risk for treatment-related complications leading to neurological sequela was low.

Endovascular treatment of intracranial dural arteriovenous fistulas with Onyx: A consecutive series of 62 patients from a single-center

OBJECTIVE

Intracranial intracranial dural arteriovenous fistulas (DAVFs) are mainly treated with an endovascular approach and various embolic agents. The aim of this study was to investigate the efficacy and safety of Onyx embolization in the treatment of DAVFs and characterize the factors as sociated with complete obliteration.

METHODS

This retrospective study was based on 62 patients with DAVFs who underwent endovascular treatment with Onyx alone or in combination with coils at our institution. Clinical and imaging data were collected and analyzed.

RESULTS

A total of 62 patients with 64 DAVFs were treated with endovascular embolization. The most common primary symptom was ophthalmological signs with a rate of 37.1%. Cognard type III was the most commonly seen subtype (32.8%). The immediate complete occlusion and follow-up rate was 92.2% and 93.5%, respectively. Transvenous balloon-assisted sinus protection was used in 12 patients (18.8%). The pressure cooker technique was used in eight patients (12.5%). Complications were seen in five patients including intracerebral hemorrhage (n = 2), venous thrombotic events (n = 2), and glued microcatheter (n = 1).

CONCLUSIONS

Endovascular Onyx alone or in combination with coils embolization is a safe and effective therapy for DAVFs. Favorable angiographic and clinical outcomes can be achieved using different endovascular approaches. Transvenous balloon-assisted sinus protection and the pressure cooker technique may help achieve complete occlusion of DAVFs.

Observation versus intervention for Borden type I intracranial dural arteriovenous fistula: A pooled analysis of 469 patients

BACKGROUND

While it is thought that Borden Type I intracranial dural arteriovenous fistula (dAVF) have a benign clinical course, their management remains controversial.

METHODS

A comparative meta-analysis was completed to evaluate the outcomes of intervention verses observation of Borden Type I intracranial dAVF. Outcome measures included: grade progression, worsening symptoms, death due to dAVF, permanent complications other than death, functional independence (mRS 0-2), and rate of death combined with permanent complication, were evaluated. Risk differences (RD) were determined using a random effects model.

RESULTS

Three comparative studies combined with the authors' institutional experience resulted in a total of 469 patients, with 279 patients who underwent intervention and 190 who were observed. There was no significant difference in dAVF grade progression between the intervention and observation arms, 1.8% vs. 0.7%, respectively (RD: 0.01, 95% CI: -0.02 to 0.04, P = 0.49), or in symptom progression occurring in 31/279 (11.1%) intervention patients and 11/190 (5.8%) observation patients (RD: 0.03, CI: -0.02 to 0.09, P = 0.28). There was also no significant difference in functional independence on follow up. However, there was a significantly higher risk of dAVF related death, permanent complication from either intervention or dAVF related ICH or stroke in the intervention group (11/279, 3.9%) compared to the observation group (0/190, 0%) (RD: 0.04, CI: 0.1 to 0.06, P = 0.007).

CONCLUSION

Intervention of Borden Type I dAVF results in a higher risk of death or permanent complication, which should be strongly considered when deciding on management of these lesions.

The VEBAS score: a practical scoring system for intracranial dural arteriovenous fistula obliteration

BACKGROUND

Tools predicting intracranial dural arteriovenous fistulas (dAVFs) treatment outcomes remain scarce. This study aimed to use a multicenter database comprising more than 1000 dAVFs to develop a practical scoring system that predicts treatment outcomes.

METHODS

Patients with angiographically confirmed dAVFs who underwent treatment within the Consortium for Dural Arteriovenous Fistula Outcomes Research-participating institutions were retrospectively reviewed. A subset comprising 80% of patients was randomly selected as training dataset, and the remaining 20% was used for validation. Univariable predictors of complete dAVF obliteration were entered into a stepwise multivariable regression model. The components of the proposed score (VEBAS) were weighted based on their ORs. Model performance was assessed using receiver operating curves (ROC) and areas under the ROC.

RESULTS

A total of 880 dAVF patients were included. Venous stenosis (presence vs absence), elderly age (<75 vs ≥75 years), Borden classification (I vs II-III), arterial feeders (single vs multiple), and past cranial surgery (presence vs absence) were independent predictors of obliteration and used to derive the VEBAS score. A significant increase in the likelihood of complete obliteration (OR=1.37 (1.27-1.48)) with each additional point in the overall patient score (range 0-12) was demonstrated. Within the validation dataset, the predicted probability of complete dAVF obliteration increased from 0% with a 0-3 score to 72-89% for patients scoring ≥8.

CONCLUSION

The VEBAS score is a practical grading system that can guide patient counseling when considering dAVF intervention by predicting the likelihood of treatment success, with higher scores portending a greater likelihood of complete obliteration.

An aggressive dural arteriovenous fistula manifested by unilateral subcortical calcification and cerebral edema: A case report

Unilateral subcortical calcifications are unique radiographic findings indicating specific focal pathologies. When the lesion is accompanied by edema, cerebral neoplasm usually leads to a differential diagnosis. This report presents a case of unilateral subcortical calcification and edema that resulted in cerebral hemorrhage and a subsequent diagnosis of an aggressive dural arteriovenous fistula. A man in his 60s presented with left hemianopsia and a progressive headache for over 6 months. Initial computed tomography revealed unilateral subcortical calcification and cerebral edema in the right occipital lobe, raising the suspicion of oligodendroglioma. However, 10 days later, a cerebral hemorrhage occurred in the lesion. Magnetic resonance imaging revealed flow void clusters and dilatation of the bilateral external carotid arteries and cortical veins, indicating a dural arteriovenous fistula. Cerebral angiography confirmed the presence of a parasagittal dural arteriovenous fistula (Borden type III). The patient was successfully treated with trans-arterial embolization using Onyx. Thus, calcifications with edema are more commonly associated with cerebral neoplasms; however, in this case, they indicated the presence of a dural arteriovenous fistula with severe corticovenous reflux. The presented case highlights the importance of recognizing these imaging features in dural arteriovenous fistulas and raises awareness of the potential danger of early hemorrhage after diagnosis. Therefore, timely evaluation of cranial vessels is essential in cases of unilateral subcortical calcification and edema to facilitate the early detection and management of aggressive dural arteriovenous fistulas.

Natural history, angiographic presentation and outcomes of anterior cranial fossa dural arteriovenous fistulas

BACKGROUND

Anterior cranial fossa dural arteriovenous fistulas (ACF-dAVFs) are aggressive vascular lesions. The pattern of venous drainage is the most important determinant of symptoms. Due to the absence of a venous sinus in the anterior cranial fossa, most ACF-dAVFs have some degree of drainage through small cortical veins. We describe the natural history, angiographic presentation and outcomes of the largest cohort of ACF-dAVFs.

METHODS

The CONDOR consortium includes data from 12 international centers. Patients included in the study were diagnosed with an arteriovenous fistula between 1990-2017. ACF-dAVFs were selected from a cohort of 1077 arteriovenous fistulas. The presentation, angioarchitecture and treatment outcomes of ACF-dAVF were extracted and analyzed.

RESULTS

60 ACF-dAVFs were included in the analysis. Most ACF-dAVFs were symptomatic (38/60, 63%). The most common symptomatic presentation was intracranial hemorrhage (22/38, 57%). Most ACF-dAVFs drained through cortical veins (85%, 51/60), which in most instances drained into the superior sagittal sinus (63%, 32/51). The presence of cortical venous drainage predicted symptomatic presentation (OR 9.4, CI 1.98 to 69.1, p=0.01). Microsurgery was the most effective modality of treatment. 56% (19/34) of symptomatic patients who were treated had complete resolution of symptoms. Improvement of symptoms was not observed in untreated symptomatic ACF-dAVFs.

CONCLUSION

Most ACF-dAVFs have a symptomatic presentation. Drainage through cortical veins is a key angiographic feature of ACF-dAVFs that accounts for their malignant course. Microsurgery is the most effective treatment. Due to the high risk of bleeding, closure of ACF-dAVFs is indicated regardless of presentation.

Neuronal dysfunction and hemodynamic disturbance due to venous congestion in dural arteriovenous fistula revealed by 123I-iomazenil SPECT

OBJECTIVE

Retrograde leptomeningeal venous drainage (RLVD) of a dural arteriovenous fistula (dAVF) is associated with neurological morbidity and unfavorable outcomes. However, the direct damage to cortical neurons by dAVF with RLVD has not been elucidated. 123I-iomazenil (123I-IMZ) SPECT can reveal cerebral blood flow and cortical neuronal damage in early and late images, respectively. This study aimed to assess the cerebral venous congestive encephalopathy caused by dAVF using 123I-IMZ SPECT.

METHODS

Based on the pre- and posttreatment MRI findings, patients were divided into three groups: a normal group, an edema group, and an infarction group. Radioactive counts in the early and late images of 123I-IMZ SPECT were investigated using the affected-to-contralateral side asymmetry ratio (ACR).

RESULTS

None of the patients in the normal group showed any symptoms related to venous congestion. In contrast, all the patients in the edema and infarction groups developed neurological symptoms. The ACR in early images in the edema group was significantly lower than that in the normal group and significantly higher than that in the infarction group. The ACR in the late images of the infarction group was significantly lower than those of the normal and edema groups. After treatment, the neurological signs disappeared in the edema group, but only partial improvement was observed in the infarction group. The ACR in early images significantly improved after treatment in the edema group, but the ACR in late images did not change in any groups.

CONCLUSIONS

123I-IMZ SPECT is useful for evaluating hemodynamic disturbances and neuronal damage in dAVFs. The reduction in early images was correlated with the severity of venous congestive encephalopathy, and the significant reduction in late images is a reliable indicator of irreversible venous infarction caused by RLVD.

A summary of common grading systems used in neurosurgical practice

Background:

Grading and scoring systems are routinely used across various specialties in medicine and surgery. They help us assess the severity of disease and often guide management as well. In addition, grading systems allow us to prognosticate and gauge outcomes. Neurosurgeons also utilize an array of scores and grading systems. This article aims to collate some of the common grading systems used in neurosurgical practice to be utilized as an easy reference especially for junior doctors and other health-care providers working in this field.

Methods:

An initial literature search was carried out to look at the grading systems in use. These were then distilled down to the ones that are frequently used in clinical neurosurgical practice based on my own experience as a doctor working in a tertiary neurosurgical unit. Neuro-oncology scoring systems were excluded from the study.

Results:

Grading systems are grouped based on the area of neurosurgical practice they fall into such as cranial, vascular, spinal, and miscellaneous. A brief description of each grading system is provided and the conditions when they can be used in a tabular format. Discussion on the advantages and disadvantages of each grading system is not included in the study.

Conclusion:

The list of grading systems in this article is not exhaustive. To the best of my knowledge, there seems to be no recent article, which summarizes them concisely. I hope that this summary will benefit the neurosurgical community and wider audience.

Risk of Early Versus Later Rebleeding From Dural Arteriovenous Fistulas With Cortical Venous Drainage

BACKGROUND

Cranial dural arteriovenous fistulas with cortical venous drainage are rare lesions that can present with hemorrhage. A high rate of rebleeding in the early period following hemorrhage has been reported, but published long-term rates are much lower. No study has examined how risk of rebleeding changes over time. Our objective was to quantify the relative incidence of rebleeding in the early and later periods following hemorrhage.

METHODS

Patients with dural arteriovenous fistula and cortical venous drainage presenting with hemorrhage were identified from the multinational CONDOR (Consortium for Dural Fistula Outcomes Research) database. Natural history follow-up was defined as time from hemorrhage to first treatment, rebleed, or last follow-up. Rebleeding in the first 2 weeks and first year were compared using incidence rate ratio and difference.

RESULTS

Of 1077 patients, 250 met the inclusion criteria and had 95 cumulative person-years natural history follow-up. The overall annualized rebleed rate was 7.3% (95% CI, 3.2-14.5). The incidence rate of rebleeding in the first 2 weeks was 0.0011 per person-day; an early rebleed risk of 1.6% in the first 14 days (95% CI, 0.3-5.1). For the remainder of the first year, the incidence rate was 0.00015 per person-day; a rebleed rate of 5.3% (CI, 1.7-12.4) over 1 year. The incidence rate ratio was 7.3 (95% CI, 1.4-37.7; P, 0.026).

CONCLUSIONS

The risk of rebleeding of a dural arteriovenous fistula with cortical venous drainage presenting with hemorrhage is increased in the first 2 weeks justifying early treatment. However, the magnitude of this increase may be considerably lower than previously thought. Treatment within 5 days was associated with a low rate of rebleeding and appears an appropriate timeframe.

Contemporary Management of Cranial Dural Arteriovenous Fistulas

Cranial dural arteriovenous fistulas (dAVFs) are rare acquired neurovascular disorders that have the potential to profoundly alter the local and global cerebral venous drainage. Factors such as location, angioarchitecture, degree of shunting, and mode of presentation all appear to have some bearing on the natural history of dAVFs, which can vary from almost entirely benign to life-threatening. Accurate and evidence-based risk stratification is, therefore, key to informing important management decisions. The treatment strategies are nuanced and, for an already rare entity, can vary tremendously from 1 fistula to another. It is only through a thorough understanding of their behavior and the treatment options available that we will be able to deliver tailored treatment to the correct dAVF and the correct patient. We aimed to provide an up-to-date summary of the reported data on the natural history and predictors of aggressive behavior for cranial dAVFs in general, followed by site-specific management considerations.

Management of Dural Arteriovenous Fistulas

Dural arteriovenous fistula (DAVF) is an acquired lesion. The dural arteries connect with the dural veins within the dura mater in the histopathological study. Sinus type involves the cavernous sinus, transverse-sigmoid sinus, superior sagittal sinus, and anterior condylar confluence (or condylar canal). Non-sinus type involves the anterior cranial base, falcotentorial region, craniocervical junction, convexity, and spinal dura mater.Radical treatment is to obliterate the draining veins in any treatment modalities including endovascular treatment or surgical treatment. Radiosurgery is the last choice. Transvenous embolization plays a main role in the DAVF of the cavernous sinus and anterior condylar confluence. Transarterial embolization with Onyx has dramatically improved the obliteration rate of the transverse-sigmoid, superior sagittal sinuses, and other non-sinus lesions. Transarterial NBCA injection is still the gold standard in the endovascular treatment of the spinal dural and epidural AVFs. Understanding of the functional microvascular anatomy is mandatory, especially in the transarterial liquid injection (Onyx and NBCA). Surgical treatment in the DAVF of the anterior cranial base, craniocervical junction, tentorial region, and spine is a safe and radical treatment. Postoperative follow-up is necessary from the viewpoint of chronological and spacial multi-occurrence of this disease.

Vascular intracranial malformations and dementia: An under-estimated cause and clinical correlation. Clinical note

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Cerebrovascular malformations (CVMs) such as arteriovenous malformations (AVMs) or dural arteriovenous fistulas (DAVFs) in addition to hemorrhagic presentation or focal neurological deficit, may manifest with global brain dysfunction resulting in dementia.

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Dementias secondary to CVMs constitute a probably underestimated subpopulation of patients of great interest because they present with devastating but potentially reversible cognitive impairment.

Cerebrovascular malformations (CVMs) such as arteriovenous malformations (AVMs) or dural arteriovenous fistulas (DAVFs) represent a possible source of intracranial hemorrhage, but these malformations can also manifest with neurologic disorders secondary to ischemic penumbra from vascular steal. In the latter case, the clinical manifestations are less obvious and characteristic, and may include a varied clinical spectrum ranging from focal deficits to generalized malfunction of the brain parenchyma resulting in dementia. Dementias secondary to CVMs constitute a probably underestimated subpopulation of patients of great interest because they present with devastating but potentially reversible cognitive impairment. We examined the pertinent literature regarding the clinical manifestations of CVMs characterized by cognitive impairment and describe the distinctive clinical features. Our results confirm that cognitive impairment is one of the clinical manifestations of CVMs and is a frequently misrecognized and often late-diagnosed cause of reversible dementia.

Endovascular versus surgical treatment of cranial dural arteriovenous fistulas: a single-center 8-year experience

BACKGROUND

Cranial dural arteriovenous fistulas (dAVFs) are rare lesions managed mainly with endovascular treatment (EVT) and/or surgery. We hypothesize that there may be subtypes of dAVFs responding better to a specific treatment modality in terms of successful obliteration and cessation of symptoms and/or risks.

METHODS

All dAVFs treated during 2011-2018 at our hospital were analyzed retrospectively. Presenting symptoms, radiological variables, treatment modality, complications, and residual symptoms were related to dAVF type using the original Djindjian classification.

RESULTS

We treated 112 dAVFs in 107 patients (71, 66% males). They presented with hemorrhage (n = 23; 21%), non-hemorrhagic symptoms (n = 75; 70%), or were discovered incidentally (n = 9; 8%). There were 25 (22%) type I, 29 (26%) type II, 26 (23%) type III, and 32 (29%) type IV fistulas. EVT was the primary treatment modality in 72/112 (64%) dAVFs whereas 40/112 (36%) underwent primary surgery with angiographic obliteration rates of 60% and 90%, respectively. Using a secondary treatment modality in 23 dAVFs, we obtained a final obliteration rate of 93%, including all type III/IV and 26/27 (96%) type II dAVFs. Except for headache, residual symptoms were rare and minor. Permanent neurological complications consisted of five cranial nerve deficits.

CONCLUSIONS

We recommend EVT as first treatment modality in types I, II, and in non-hemorrhagic type III/IV dAVFs. We recommend surgery as first treatment choice in acute hemorrhagic dAVFs and as secondary choice in type III/IV dAVFs not successfully occluded by EVT. Combining the two modalities provides obliteration in 9/10 dAVF cases at a low procedural risk.

Intracranial Dural Arteriovenous Fistulas with Cortical Venous Drainage: Radiosurgery as an Effective Alternative Treatment

OBJECTIVE

To evaluate the clinical and radiological outcome of Gamma Knife radiosurgery (GKS) in treatment of intracranial dural arteriovenous fistula (DAVF) with cortical venous drainage (CVD) and compare it with the outcome of endovascular therapy.

METHODS

Patients who underwent GKS or endovascular therapy for intracranial DAVF with CVD over 10 years (January 2007 to December 2016) at the All India Institute of Medical Sciences, New Delhi, were included. Demographics, clinical presentation, imaging details, and follow-up clinical status were reviewed retrospectively. Clinical follow-up was conducted once every 6 months. Radiological follow-up using digital subtraction angiography was performed at a mean 24 months after intervention. Patients with clinical follow-up of <1 year were excluded from the study.

RESULTS

The study included 35 patients (26 in embolization group and 9 in GKS group) who had intracranial DAVF with CVD were included in the study. Clinical improvement was seen in 77.78% of the patients who received GKS and 57.7% of the patients who underwent embolization (P = 0.431). Complete obliteration of DAVF was seen in 55.56% of the patients in the GKS group and 57.7% of the patients in the embolization group (P = 1). GKS was at least as effective as embolization in terms of clinical and radiological outcome in treatment of intracranial DAVF with CVD.

CONCLUSIONS

Contrary to popular perception, GKS should be considered as an effective first-line treatment alternative of intracranial DAVF with CVD.

Intervention for unruptured high-grade intracranial dural arteriovenous fistulas: a multicenter study

OBJECTIVE

The risk-to-benefit profile of treating an unruptured high-grade dural arteriovenous fistula (dAVF) is not clearly defined. The aim of this multicenter retrospective cohort study was to compare the outcomes of different interventions with observation for unruptured high-grade dAVFs.

METHODS

The authors retrospectively reviewed dAVF patients from 12 institutions participating in the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR). Patients with unruptured high-grade (Borden type II or III) dAVFs were included and categorized into four groups (observation, embolization, surgery, and stereotactic radiosurgery [SRS]) based on the initial management. The primary outcome was defined as the modified Rankin Scale (mRS) score at final follow-up. Secondary outcomes were good outcome (mRS scores 0-2) at final follow-up, symptomatic improvement, all-cause mortality, and dAVF obliteration. The outcomes of each intervention group were compared against those of the observation group as a reference, with adjustment for differences in baseline characteristics.

RESULTS

The study included 415 dAVF patients, accounting for 29, 324, 43, and 19 in the observation, embolization, surgery, and SRS groups, respectively. The mean radiological and clinical follow-up durations were 21 and 25 months, respectively. Functional outcomes were similar for embolization, surgery, and SRS compared with observation. With observation as a reference, obliteration rates were higher after embolization (adjusted OR [aOR] 7.147, p = 0.010) and surgery (aOR 33.803, p < 0.001) and all-cause mortality was lower after embolization (imputed, aOR 0.171, p = 0.040). Hemorrhage rates per 1000 patient-years were 101 for observation versus 9, 22, and 0 for embolization (p = 0.022), surgery (p = 0.245), and SRS (p = 0.077), respectively. Nonhemorrhagic neurological deficit rates were similar between each intervention group versus observation.

CONCLUSIONS

Embolization and surgery for unruptured high-grade dAVFs afforded a greater likelihood of obliteration than did observation. Embolization also reduced the risk of death and dAVF-associated hemorrhage compared with conservative management over a modest follow-up period. These findings support embolization as the first-line treatment of choice for appropriately selected unruptured Borden type II and III dAVFs.

Interdisciplinary treatment of posterior fossa dural arteriovenous fistulas

BACKGROUND

Posterior fossa dural arteriovenous fistulas (dAVFs) are rare vascular lesions with variable risk of hemorrhage, mostly depending on the pattern of the venous drainage. While endovascular embolization is the mainstay treatment for most dAVFs, some posterior fossa lesions require a multidisciplinary approach including surgery. The goal of our study was to examine the outcome of an interdisciplinary treatment for posterior fossa dAVFs.

METHODS

A retrospective review of patients treated for posterior fossa dAVFs was conducted.

RESULTS

A total of 28 patients with a mean age of 57.8 years were included. Patients presented with a Cognard grade I in 2 (7%), II a in 5 (18 %), II b in 7 (25%), II a + b in 5 (18%), III in 3 (11%), and IV in 6 (21%) cases. Hemorrhage was the initial presentation in 2 (22%) patients with Cognard grade IV, in 3 with Cognard grade III (33%), in 1 (11%) with Cognard II a + b, and 3 (33%) with Cognard II b. A complete angiographic cure was achieved in 24 (86%) patients-after a single-session embolization in 16 (57%) patients, multiple embolization sessions in 2 (7%), a multimodal treatment with embolization and surgical disconnection in 3 (11%), and with an upfront surgery in 3 (11%). Complete long-term obliteration was demonstrated in 18/22 (82%) at the mean follow-up of 17 months. Fistulas were converted into asymptomatic Cognard I lesion in 4 (14%) patients.

CONCLUSION

Posterior fossa dAVFs represent a challenging vascular pathology; however, despite their complexity, an interdisciplinary treatment can achieve high rates of angiographic and symptomatic cure with low morbidity and mortality rates. Long-term surveillance is warranted as late recurrences may occur.

Cerebral venous drainage in patients with dural arteriovenous fistulas: correlation with clinical presentation

OBJECTIVE

Dural arteriovenous fistulas (DAVFs) are abnormal, acquired arteriovenous connections within the dural leaflets. Their associated symptoms may be mild or severe and are related to the patient's venous anatomy. With the hypothesis that the patient's venous anatomy determines the development of symptoms, the authors aimed to identify which venous anatomy elements are important in the development of major symptoms in patients with a DAVF.

METHODS

A multicenter study was performed based on the retrospective analysis of cerebral angiographies with systematic assessment of brain drainage pathways (including fistula drainage) in patients over 18 years of age with a single DAVF. The patients were divided into two groups: those with minor (group 1, n = 112) and those with major (group 2, n = 89) symptoms. Group 2 was subdivided into two groups: patients with hemorrhage (group 2a, n = 47) and patients with severe nonhemorrhagic symptoms (group 2b, n = 42).

RESULTS

The prevalence of stenosis in DAVF venous drainage and the identification of tiny anastomoses between venous territories were significantly higher in group 2 (32.6% and 19.1%, respectively) compared with group 1 (2.68% and 5.36%, respectively). Stenosis of DAVF venous drainage was significantly more frequent in group 2a than in group 2b (51.1% vs 11.9%, p < 0.001). Group 2b patients had increased prevalence of shared use of the cerebral main drainage pathway (85.0% vs 53.2%, p = 0.002), the absence of an alternative route (45.0% vs 17.0%, p = 0.004), and the presence of contrast stagnation (62.5% vs 29.8%, p = 0.002) compared with group 2a patients. In patients with high-grade fistulas, the group with major symptoms had increased prevalence of a single draining direction (31.3% vs 8.33%, p = 0.003), stenosis in the draining vein (35.0% vs 6.25%, p = 0.000), the absence of an alternative pathway for brain drainage (31.3% vs 12.5%, p = 0.017), and the presence of contrast stagnation (48.8% vs 22.9%, p = 0.004).

CONCLUSIONS

Major symptoms were observed when normal brain tissue venous drainage was impaired by competition with DAVF (predominance in group 2b) or when DAVF venous drainage had anatomical characteristics that hindered drainage, with consequent venous hypertension on the venous side of the DAVF (predominance in group 2a). The same findings were observed when comparing two groups of patients with high-grade lesions: those with major versus those with minor symptoms.

Observation Versus Intervention for Low-Grade Intracranial Dural Arteriovenous Fistulas

BACKGROUND

Low-grade intracranial dural arteriovenous fistulas (dAVF) have a benign natural history in the majority of cases. The benefit from treatment of these lesions is controversial.

OBJECTIVE

To compare the outcomes of observation versus intervention for low-grade dAVFs.

METHODS

We retrospectively reviewed dAVF patients from institutions participating in the CONsortium for Dural arteriovenous fistula Outcomes Research (CONDOR). Patients with low-grade (Borden type I) dAVFs were included and categorized into intervention or observation cohorts. The intervention and observation cohorts were matched in a 1:1 ratio using propensity scores. Primary outcome was modified Rankin Scale (mRS) at final follow-up. Secondary outcomes were excellent (mRS 0-1) and good (mRS 0-2) outcomes, symptomatic improvement, mortality, and obliteration at final follow-up.

RESULTS

The intervention and observation cohorts comprised 230 and 125 patients, respectively. We found no differences in primary or secondary outcomes between the 2 unmatched cohorts at last follow-up (mean duration 36 mo), except obliteration rate was higher in the intervention cohort (78.5% vs 24.1%, P < .001). The matched intervention and observation cohorts each comprised 78 patients. We also found no differences in primary or secondary outcomes between the matched cohorts except obliteration was also more likely in the matched intervention cohort (P < .001). Procedural complication rates in the unmatched and matched intervention cohorts were 15.4% and 19.2%, respectively.

CONCLUSION

Intervention for low-grade intracranial dAVFs achieves superior obliteration rates compared to conservative management, but it fails to improve neurological or functional outcomes. Our findings do not support the routine treatment of low-grade dAVFs.

Rapidly progressive dementia and Parkinsonism as the first symptoms of dural arteriovenous fistula. The Sapienza University experience and comprehensive literature review concerning the clinical course of 102 patients

BACKGROUND

Dementia is a chronic loss of neurocognitive function that is progressive and irreversible. Dural arteriovenous fistulas (DAVFs) are acquired lesions that account for 10-15% of intracranial vascular malformations that could present with a rapid decline in neurocognitive function with or without Parkinson-like symptoms and evolve in a rapidly progressive dementia (RPD). Often the DAVFs are not even included in the differential hypotheses of this type of dementia and are not present in any type of diagnostic algorithm for evaluating RPD.

METHODS

We performed a systematic review of the international literature and adding the cases coming from our institutional experience and we have collected all the reported cases of DAVFs that debut with ROD identifying the most frequent forms in terms of location and type, reporting the neurological characteristics and the outcome of each patient.

RESULTS

The exact pathogenesis for developing dementia in patients with DAVFs remains largely unknown. The imaging changes and pathologic findings support the hypothesis that the clinical course results from the delivery of excessive volumes of blood flow into a venous system with outflow obstruction and venous congestion. The large variety of clinical manifestations of DAVFs depends on its location but this is not exactly valid for the onset of dementia. It supposed that the highly variable clinical manifestation of DAVFs has been convincingly related to the pattern of venous drainage more than location.

CONCLUSIONS

Neurologists and clinicians generally are familiar with the differential diagnoses of slowly progressive neurodegenerative dementias, but the diagnosis of RPD entails a different diagnostic approach. Due to their curable nature, the diagnosis of DAVFs must be suspected when facing a RPD picture, even more so if it is associated with characteristic abnormalities of the hemispheric white matter.

Relative signal intensity on time-of-flight magnetic resonance angiography as a novel indicator of aggressive presentation of intracranial dural arteriovenous fistulas

Asymptomatic dural arteriovenous fistulas (DAVFs) with cortical venous reflux (CVR) are now more commonly encountered. However, patients with an incidental onset may have a less aggressive clinical course. It is desirable to explore methods and indicators to predict the clinical outcomes. This study investigates whether the relative signal intensity (rSI) of the draining vessels on the time-of-flight magnetic resonance angiography is related to clinical behavior in patients with intracranial DAVFs. We retrospectively reviewed 36 intracranial DAVFs. The patients were categorized as those with either aggressive-presentation or non-aggressive-presentation (n = 16 and 20, respectively). The rSIs of the shunt points, affected sinuses, and veins with CVR were compared between the two groups. The two groups were not significantly different in terms of rSIs of the shunt points and affected sinuses (p = 0.37 and 0.41, respectively). However, a significant positive correlation was observed in the rSI of the veins with CVR between the aggressive and non-aggressive behavior groups (p < 0.0001). The rSI of the veins with CVR could serve as a reliable indicator of aggressive behavior in intracranial DAVFs, and its optimal cutoff value was 1.63 with high sensitivity and specificity for predicting aggressive behavior (area under the curve, 0.909).

Detection Rate and Radiological Features of Asymptomatic Intracranial Dural Arteriovenous Fistula: Analysis of Magnetic Resonance Imaging Data of 11745 Individuals in the Japanese Brain Check-Up System

Objective

Asymptomatic intracranial dural arteriovenous fistula (DAVF) is a rare disease that is often undiagnosed before symptom onset. The present study aimed to examine the detection rate and radiological features of asymptomatic intracranial DAVF using brain MRI data obtained from the Japanese brain check-up system.

Methods

We retrospectively identified 11745 individuals who underwent brain MRI between January 2010 and December 2014. After a routine brain MRI screening, a definite diagnosis was made based on DSA. Data regarding sex, age, disease location, classification type, and treatment method were extracted from the system database and patients' medical records.

Results

Six individuals (0.05%; mean age, 61.0 ± 9.7 years) were diagnosed with definite intracranial DAVF. The intracranial DAVFs were located in the transverse sinus, confluence, and tentorial sinus in 2, 1, and 3 case(s), respectively. Cortical venous reflux was confirmed in four cases (66.7%), and none of the cases had intracranial hemorrhage or venous congestion. All cases had infratentorial lesions and two-thirds were Borden type II/III.

Conclusion

The detection rate of asymptomatic intracranial DAVF was 0.05% based on the analysis of MRI data from the brain check-up system. Low-flow shunt and tiny cortical venous reflux were likely missed on MRI.

A Proposed Grading Scale for Predicting Outcomes After Stereotactic Radiosurgery for Dural Arteriovenous Fistulas

BACKGROUND

There are presently no grading scales that specifically address the outcomes of cranial dural arteriovenous fistula (dAVF) after stereotactic radiosurgery (SRS).

OBJECTIVE

To design a practical grading system that would predict outcomes after SRS for cranial dAVFs.

METHODS

From the International Radiosurgery Research Foundation (University of Pittsburgh [41 patients], University of Pennsylvania [6 patients], University of Sherbrooke [2 patients], University of Manitoba [1 patient], West Virginia University [2 patients], University of Puerto Rico [1 patient], Beaumont Health System 1 [patient], Na Homolce Hospital [13 patients], the University of Virginia [48 patients], and Yale University [6 patients]) centers, 120 patients with dAVF treated with SRS were included in the study. The factors predicting favorable outcome (obliteration without post-SRS hemorrhage) after SRS were assessed using logistic regression analysis. These factors were pooled with the factors that were found to be predictive of obliteration from 7 studies with 736 patients after a systematic review of literature. These were entered into stepwise multiple regression and the best-fit model was identified.

RESULTS

Based on the predictive model, 3 factors emerged to develop an SRS scoring system: cortical venous reflux (CVR), prior intracerebral hemorrhage (ICH), and noncavernous sinus location. Class I (score of 0-1 points) predicted the best favorable outcome of 80%. Class II patients (2 points score) had an intermediate favorable outcome of 57%, and class III (score 3 points) had the least favorable outcome at 37%. The ROC analysis showed better predictability to prevailing grading systems (AUC = 0.69; P = .04). Kaplan-Meier analysis showed statistically significant difference between the 3 subclasses of the proposed grading system for post-SRS dAVF obliteration (P = .001).

CONCLUSION

The proposed dAVF grading system incorporates angiographic, anatomic, and clinical parameters and improves the prediction of the outcomes following SRS for dAVF as compared to the existing scoring systems.

Gamma Knife Radiosurgery: The Gold Standard Treatment for Intracranial Dural Arteriovenous Fistulas without Cortical Venous Drainage

Context

Endovascular therapy is currently the most common treatment approach for intracranial dural arteriovenous fistula (DAVF), followed by microsurgery. Gamma Knife radiosurgery (GKS) is usually reserved as the last modality of treatment of intracranial DAVF.

Aim

To evaluate the clinical and radiological outcome of GKS in the treatment of DAVF without CVD.

Subjects and Methods

This series includes patients who underwent GKS for intracranial DAVF without CVD over 10 years (Jan 2007 to Dec 2016) in All India Institute of Medical Sciences, New Delhi. Their demographic profile, clinical presentation, imaging details, GKS details, and follow-up clinical status were obtained retrospectively. Clinical follow-up, along with radiological assessment using MRI every 6 months was done after GKS. DSA was performed once MRI strongly suggested obliteration of DAVF. Patients who had a clinical follow-up of less than 1 year were excluded from the study.

Results

5 patients (4 males and 1 female) who had DAVF without CVD were included the study. The mean age was 44.8 years. All patients had complete obliteration of fistula on digital subtraction angiography (DSA) at a mean duration of 24 months post GKS. All patients had complete resolution of symptoms at the last follow-up.

Conclusions

Gamma Knife surgery is the most effective and the safest treatment modality for dealing with DAVFs without CVD. Instead of reserving it as the last resort for patients with DAVF without CVD, it should be considered as the gold standard treatment for DAVFs without CVD.

Fatal Hemorrhage Immediately after Transvenous Embolization of Transverse-sigmoid Sinus Dural Arteriovenous Fistulas: A Case Report

Objective

We report a case of intracerebral hemorrhage following emergency transvenous embolization for an acute symptomatic non-hemorrhagic dural arteriovenous fistula (dAVF).

Case Presentation

An 83-year-old woman demonstrated gait disorder and disturbance of consciousness. A transverse-sigmoid dAVF with retrograde deep venous drainage was detected on DSA. The left sigmoid sinus-jugular vein and the sinus confluence were occluded and the dAVF drains via the straight sinus (SS), medial superior cerebral veins and deep veins to the superior sagittal sinus (SSS). The dAVF was emergently treated by sinus packing of the transverse-sigmoid sinus with coils with contralateral approach via the occluded sinus confluence. Although the dAVF was markedly regressed, massive cerebral hemorrhage developed in the left parietal lobe immediately after embolization.

Conclusion

Although early treatment is required for dAVFs with aggressive symptoms, precious evaluation of their hemodynamics, particularly for drainage pattern, is mandatory to avoid a serious complication.

Hemorrhage risk of cerebral dural arteriovenous fistulas following Gamma Knife radiosurgery in a multicenter international consortium

OBJECTIVE

The authors performed a study to evaluate the hemorrhagic rates of cerebral dural arteriovenous fistulas (dAVFs) and the risk factors of hemorrhage following Gamma Knife radiosurgery (GKRS).

METHODS

Data from a cohort of patients undergoing GKRS for cerebral dAVFs were compiled from the International Radiosurgery Research Foundation. The annual posttreatment hemorrhage rate was calculated as the number of hemorrhages divided by the patient-years at risk. Risk factors for dAVF hemorrhage prior to GKRS and during the latency period after radiosurgery were evaluated in a multivariate analysis.

RESULTS

A total of 147 patients with dAVFs were treated with GKRS. Thirty-six patients (24.5%) presented with hemorrhage. dAVFs that had any cortical venous drainage (CVD) (OR = 3.8, p = 0.003) or convexity or torcula location (OR = 3.3, p = 0.017) were more likely to present with hemorrhage in multivariate analysis. Half of the patients had prior treatment (49.7%). Post-GRKS hemorrhage occurred in 4 patients, with an overall annual risk of 0.84% during the latency period. The annual risks of post-GKRS hemorrhage for Borden type 2-3 dAVFs and Borden type 2-3 hemorrhagic dAVFs were 1.45% and 0.93%, respectively. No hemorrhage occurred after radiological confirmation of obliteration. Independent predictors of hemorrhage following GKRS included nonhemorrhagic neural deficit presentation (HR = 21.6, p = 0.027) and increasing number of past endovascular treatments (HR = 1.81, p = 0.036).

CONCLUSIONS

Patients have similar rates of hemorrhage before and after radiosurgery until obliteration is achieved. dAVFs that have any CVD or are located in the convexity or torcula were more likely to present with hemorrhage. Patients presenting with nonhemorrhagic neural deficits and a history of endovascular treatments had higher risks of post-GKRS hemorrhage.

Evaluation of stereotactic radiosurgery for cerebral dural arteriovenous fistulas in a multicenter international consortium

OBJECTIVE

In this multicenter study, the authors reviewed the results obtained in patients who underwent Gamma Knife radiosurgery (GKRS) for dural arteriovenous fistulas (dAVFs) and determined predictors of outcome.

METHODS

Data from a cohort of 114 patients who underwent GKRS for cerebral dAVFs were compiled from the International Gamma Knife Research Foundation. Favorable outcome was defined as dAVF obliteration and no posttreatment hemorrhage or permanent symptomatic radiation-induced complications. Patient and dAVF characteristics were assessed to determine predictors of outcome in a multivariate logistic regression analysis; dAVF-free obliteration was calculated in a competing-risk survival analysis; and Youden indices were used to determine optimal radiosurgical dose.

RESULTS

A mean margin dose of 21.8 Gy was delivered. The mean follow-up duration was 4 years (range 0.5-18 years). The overall obliteration rate was 68.4%. The postradiosurgery actuarial rates of obliteration at 3, 5, 7, and 10 years were 41.3%, 61.1%, 70.1%, and 82.0%, respectively. Post-GRKS hemorrhage occurred in 4 patients (annual risk of 0.9%). Radiation-induced imaging changes occurred in 10.4% of patients; 5.2% were symptomatic, and 3.5% had permanent deficits. Favorable outcome was achieved in 63.2% of patients. Patients with middle fossa and tentorial dAVFs (OR 2.4, p = 0.048) and those receiving a margin dose greater than 23 Gy (OR 2.6, p = 0.030) were less likely to achieve a favorable outcome. Commonly used grading scales (e.g., Borden and Cognard) were not predictive of outcome. Female sex (OR 1.7, p = 0.03), absent venous ectasia (OR 3.4, p < 0.001), and cavernous carotid location (OR 2.1, p = 0.019) were predictors of GKRS-induced dAVF obliteration.

CONCLUSIONS

GKRS for cerebral dAVFs achieved obliteration and avoided permanent complications in the majority of patients. Those with cavernous carotid location and no venous ectasia were more likely to have fistula obliteration following radiosurgery. Commonly used grading scales were not reliable predictors of outcome following radiosurgery.

Gamma Knife Radiosurgery For Brain Vascular Malformations: Current Evidence And Future Tasks

Gamma Knife radiosurgery (GKRS) has long been used for treating brain vascular malformations, including arteriovenous malformations (AVMs), dural arteriovenous fistulas (DAVFs), and cavernous malformations (CMs). Herein, current evidence and controversies regarding the role of stereotactic radiosurgery for vascular malformations are described. 1) It has already been established that GKRS achieves 70–85% obliteration rates after a 3–5-year latency period for small to medium-sized AVMs. However, late radiation-induced adverse events (RAEs) including cyst formation, encapsulated hematoma, and tumorigenesis have recently been recognized, and the associated risks, clinical courses, and outcomes are under investigation. SRS-based therapeutic strategies for relatively large AVMs, including staged GKRS and a combination of GKRS and embolization, continue to be developed, though their advantages and disadvantages warrant further investigation. The role of GKRS in managing unruptured AVMs remains controversial since a prospective trial showed no benefit of treatment, necessitating further consideration of this issue. 2) Regarding DAVFs, GKRS achieves 41–90% obliteration rates at the second post-GKRS year with a hemorrhage rate below 5%. Debate continues as to whether GKRS might serve as a first-line solo therapeutic modality given its latency period. Although the post-GKRS outcomes are thought to differ among lesion locations, further outcome analyses regarding DAVF locations are required. 3) GKRS is generally accepted as an alternative for small or medium-sized CMs in which surgery is considered to be too risky. The reported hemorrhage rates ranged from 0.5–5% after GKRS. Higher dose treatments (>15 Gy) were performed during the learning curve, while, with the current standard treatment, a dose range of 12–15 Gy is generally selected, and has resulted in acceptable complication rates (< 5%). Nevertheless, further elucidation of long-term outcomes is essential.

Are type I dural arteriovenous fistulas safe? Single-centre experience of endovascular treatment of dural arteriovenous fistulas

Introduction

There are mixed reports on the incidence of intracranial haemorrhage in patients with dural arteriovenous fistulas. We assessed new proposed risk factors (i.a. number of outflows and outflow diameter) of intracerebral haemorrhage due to intracranial dural arteriovenous fistula and presented our personal experience in endovascular treatment of dural arteriovenous fistulas.

Material and methods

The patient database from January 2006 and December 2016 was reviewed, and 25 patients with 28 dural arteriovenous fistulas were identified.

Results

50% of patients presented with intracerebral haemorrhage. Multiple dural fistulas occurred in 12% of patients. Spearman’s rank correlation coefficient revealed that there was a strong association between Cognard classification type and time needed to treat (r = 0.59, p < 0.05), as well as the volume of contrast used (r = 0.77, p < 0.05). Infratentorial (r = 0.53, p < 0.05) and right-sided (r = 0.66, p < 0.05) localisation were more challenging to treat. Bleeding was associated with poorer clinical outcome (r = 0.48, p < 0.05). No significant differences were found between the non-haemorrhagic group and the haemorrhagic group regarding the number of outflows (p = 0.459) and largest outflow diameter (p = 0.298). Clinical evaluation at follow-up was as follows: 56% of patients were asymptomatic, 24% had non-significant disability, maintaining independency, 16% had moderate disability, and 8% died – one in the course of intracerebral haemorrhage and one due to other sustained injuries. There were no reported embolisation-related complications.

Conclusions

To conclude, regardless of presentation, both symptomatic and asymptomatic dural arteriovenous fistulas deserve clinical attention, structured evaluation, and follow-up. Type I fistulas were associated with haemorrhage in 1/3 of all cases. Overall our results indicate that the risk of haemorrhage and dire consequences is multifactorial.

T2-Weighted-Fluid-Attenuated Inversion Recovery Hyperintensity on Magnetic Resonance Imaging Is Associated With Aggressive Symptoms in Patients With Dural Arteriovenous Fistulas

Background and Purpose- Several angiographic factors of dural arteriovenous fistulas (dAVFs) are associated with aggressive presentation and poor natural history. We examined the association of magnetic resonance imaging T2-weighted-Fluid-Attenuated Inversion Recovery (T2/FLAIR) hyperintensity with aggressive presentation. Methods- A cohort of dAVF patients from 2 centers was retrospectively examined. T2/FLAIR hyperintensity was determined by blinded, de-identified review and compared with angiographic grade and presenting symptoms. Results- T2/FLAIR hyperintensity was only identified in dAVF patients with cortical venous drainage (CVD). Among patients with CVD, those with T2/FLAIR hyperintensity were more likely to present with aggressive symptoms (20/23, 87.0%) than those without (6/21, 28.5%), P<0.001. All cured dAVFs with symptom resolution and available post-treatment imaging had resolution of T2/FLAIR hyperintensity. Conclusions- T2/FLAIR hyperintensity strongly correlates with aggressive presentation and CVD in dAVF patients, and may identify a subset that would benefit from early treatment.

Reconsidering an important subclass of high-risk dural arteriovenous fistulas for stereotactic radiosurgery

OBJECTIVE

Aggressive dural arteriovenous fistulas (dAVFs) with cortical venous drainage (CVD) are known for their relatively high risk of recurrent neurological events or hemorrhage. However, recent natural history literature has indicated that nonaggressive dAVFs with CVD have a significantly lower prospective risk of hemorrhage. These nonaggressive dAVFs are typically diagnosed because of symptomatic headache, pulsatile tinnitus, or ocular symptoms, as in low-risk dAVFs. Therefore, the viability of stereotactic radiosurgery (SRS) as a treatment for this lesion subclass should be investigated.

METHODS

The authors evaluated their institutional experience with SRS for dAVFs with CVD for the period from 1991 to 2016, assessing angiographic outcomes and posttreatment hemorrhage rates. They subsequently pooled their results with those published in the literature and stratified the results based on the mode of clinical presentation.

RESULTS

In an institutional cohort of 42 dAVFs with CVD treated using SRS, there were no complications or hemorrhages after treatment in 19 patients with nonaggressive dAVFs, but there was 1 radiation-induced complication and 1 hemorrhage among the 23 patients with aggressive dAVFs. In pooling these cases with 155 additional cases from the literature, the authors found that the hemorrhage rate after SRS was significantly lower among the patients with nonaggressive dAVFs (0% vs 6.8%, p = 0.003). Similarly, the number of radiation-related complications was 0/124 in nonaggressive dAVF cases versus 6/73 in aggressive dAVF cases (p = 0.001). The annual rate of hemorrhage after SRS for aggressive fistulas was 3.0% over 164.5 patient-years, whereas none of the nonaggressive fistulas bled after radiosurgery over 279.4 patient-years of follow-up despite the presence of CVD.

CONCLUSIONS

Cortical venous drainage is thought to be a significant risk factor in all dAVFs. In the institutional experience described here, SRS proved to be a low-risk strategy associated with a very low risk of subsequent hemorrhage or radiation-related complications in nonaggressive dAVFs with CVD.

A Propensity Score-Matched Cohort Analysis of Outcomes After Stereotactic Radiosurgery in Older versus Younger Patients with Dural Arteriovenous Fistula: An International Multicenter Study

OBJECTIVE

This study aims to evaluate the outcomes of Gamma Knife stereotactic radiosurgery (SRS) for dural arteriovenous fistulas (dAVFs) in older patients (≥65 years) compared with younger patients (age <65 years).

METHODS

Two groups with a total of 96 patients were selected from a database of 133 patients with dAVF from 9 international medical centers with a minimum 6 months follow-up. A 1:2 propensity matching was performed by nearest-neighbor matching criteria based on sex, Borden grade, maximum radiation dose given, and location. The older cohort consisted of 32 patients and the younger cohort consisted of 64 patients. The mean overall follow-up in the combined cohort was 42.4 months (range, 6-210 months).

RESULTS

In the older cohort, a transverse sinus location was found to significantly predict dAVF obliteration (P = 0.01). The post-SRS actuarial 3-year and 5-year obliteration rates were 47.7% and 78%, respectively. There were no cases of post-SRS hemorrhage. In the younger cohort, the cavernous sinus location was found to significantly predict obliteration (P = 0.005). The 3-year and 5-year actuarial obliteration rates were 56% and 70%, respectively. Five patients (7.8%) hemorrhaged after SRS. Margin dose ≥25 Gy was predictive of unfavorable outcome. The obliteration rate (P = 0.3), post-SRS hemorrhage rate (P = 0.16), and persistent symptoms after SRS (P = 0.83) were not statistically different between the 2 groups.

CONCLUSIONS

SRS achieves obliteration in most older patients with dAVF, with an acceptable rate of complication. There was no increased risk of postradiosurgery complications in the older cohort compared with the younger patients.

A multi-institutional analysis of the untreated course of cerebral dural arteriovenous fistulas

The authors attempted to better delineate the natural course of untreated cerebral dural arteriovenous fistulas. For a group of 295 fistulas, drainage pattern was most important in predicting the risk of future neurological events or bleeding. Moreover, presentation with a neurological event or hemorrhage was an independent risk factor for future neurological events or hemorrhage, respectively. The authors provided hemorrhage rates for various subclasses of dural arteriovenous fistulas to facilitate risk stratification, excluding partially treated lesions.

A dural arteriovenous fistula associated with an encephalocele presenting as otitis media with effusion

OBJECTIVE

This case report illustrates an unusual case of a dural arteriovenous fistula and an associated encephalocele presenting as otitis media with effusion.Case reportA 53-year-old man presented with right-sided hearing loss and aural fullness of 2 years' duration. Examination revealed ipsilateral post-auricular pulsatile tenderness. Computed tomography showed transcalvarial channels suggestive of dural arteriovenous fistula. Further magnetic resonance imaging demonstrated the presence of a temporal encephalocele herniating through the tegmen tympani defect, as well as the abnormal vascularity. Angiography confirmed a Cognard type I dural arteriovenous fistula, which is being managed conservatively. Surgical repair of the encephalocele was recommended but declined by the patient.

CONCLUSION

Dural arteriovenous fistula is an uncommon intracranial vascular malformation rarely seen by otolaryngologists, with pulsatile tinnitus being the usual presentation. To our knowledge, this is the first reported case of dural arteriovenous fistula presenting with conductive hearing loss and otalgia.

Engorged medullary vein on CT angiography in patients with dural arteriovenous fistula: prevalence, types, and comparison between regional and extensive types

BACKGROUND AND PURPOSE

Engorged medullary vein (EMV) in patients with intracranial dural arteriovenous fistula (DAVF) suggests venous congestion. The aim of this study is to investigate its prevalence, pattern, and correlation with clinical findings.

MATERIALS AND METHODS

CT angiography (CTA) raw data of DAVF were used for multiplanar reconstruction and then analyzed for the presence and pattern of EMV, which is defined as a dilated vein in the cerebral white matter. Patients with EMV were divided into two groups: regional and extensive. Regional type is defined as EMV limited to one cerebral hemisphere or cerebellum without evidence of subcortical calcification. Extensive type is defined as EMV involvement of more than one cerebral hemisphere or both the cerebrum and cerebellum. Descriptive analysis of clinical information, DAVF characteristics, and other imaging findings was conducted. Clinical information, including demographic data, clinical presentation, and hemorrhage, were correlated with both types of EMV.

RESULTS

Among 192 eligible patients with DAVF, 71 (37%) had EMV. Patients with EMV were older (63 years vs 56 years, P=0.02), with DAVF more often at the transverse and sigmoid sinus (P<0.001), and more often presented with aggressive symptoms (59% vs 34%, P=0.02) than non-EMV patients, but there was no difference in the presentation of hemorrhage (15% vs 16%, P=0.99). Patients with regional EMV had a higher proportion of hemorrhage than those with the extensive type (24% vs 0%, P=0.006).

CONCLUSIONS

EMV in patients with DAVF is associated with an aggressive manifestation. Regional type EMV is associated with a higher risk of a hemorrhagic presentation.

Outcome of transarterial treatment of dural arteriovenous fistulas with direct or indirect cortical venous drainage

BACKGROUND AND PURPOSE

Transarterial Onyx embolization is an effective treatment for patients with intracranial dural arteriovenous fistula (DAVF). A study was performed to determine whether the clinical and radiological outcomes after transarterial Onyx treatment were affected by the type of cortical venous drainage (direct vs indirect) of high-grade DAVF.

MATERIALS AND METHODS

Between May 2006 and December 2014, demographic data, clinical presentation, angiographic characteristics, and treatment-related outcomes were collected for 54 patients divided into two groups (intracranial DAVF with direct and indirect cortical venous drainage). Continuous variables were compared with the two-tailed t test and categorical variables with the χ² test. Statistical significance was set at P<0.05.

RESULTS

Fifty-two patients (71% with direct and 29% with indirect cortical venous drainage) underwent Onyx embolization. Immediate complete occlusion after treatment was observed in about 55% of patients without between-group difference. During the long-term follow-up, complete angiographic occlusion was achieved in 83% of patients. Specifically, 15 additional patients (40%) in the direct cortical venous drainage group progressed to complete occlusion, but only one (6%) in the indirect cortical venous drainage group. Overall, the rate of complete occlusion was higher in patients with DAVF with direct cortical venous drainage (92%) than in those with DAVF with indirect cortical venous drainage (62.5%) (P=0.01). The rate of permanent treatment-related complications was 4%, mostly related to ischemic events. Overall, 80.5% of patients had a good neurological outcome (modified Rankin Scale score 0-2).

CONCLUSIONS

Transarterial Onyx embolization of intracranial high-grade DAVF is safe and effective, particularly for lesions with direct cortical venous drainage.

Spontaneous Resolution of Venous Aneurysms After Transarterial Embolization of a Variant Superior Sagittal Sinus Dural Arteriovenous Fistula: Case Report and Literature Review

We present a rare case of dural arteriovenous fistula (DAVF) with subarachnoid hemorrhage and intraventricular hemorrhage due to its venous aneurysms. A 63-year-old woman was admitted for a sudden loss of consciousness. Computed tomography angiograph, magnetic resonance imaging angiography, and digital subtraction angiography revealed a superior sagittal sinus DAVF. The fistula was fed by the left middle meningeal artery and left internal carotid artery, and was drained by a right vein of Trolard, the superficial Sylvian vein, deep Sylvian vein, and basal vein to the vein of Galen. The drainage veins were enlarged obviously with 3 aneurysmal venous malformations. There was a stenosis segment on the right basal vein. All the anatomic factors of direct cortical vein drainage, normal deep vein drainage, long tortuous drainage vein, outflow restriction, and multiple venous aneurysms, were contributed to the aggressive presentation of our case. Transarterial complete embolization of the fistula with balloon protection was successfully performed. Nine months later, a follow-up magnetic resonance imaging showed a complete disappearance of the 2 venous aneurysms located in the deep Sylvian vein and basal vein, and an obvious decrease in size of the venous aneurysm of the superficial Sylvian vein. This is the first report of a DAVF with 3 ballooned venous aneurysms and a spontaneous anatomy resolution of the venous aneurysms after the embolization of the fistula. At the same time, the clinical and radiologic characteristics of variant superior sagittal sinus DAVFs were summarized by review of the literatures reported previously.

Treating intracranial dural arteriovenous fistulas with gamma knife radiosurgery: A single-center experience

Objective:

We evaluated the effectiveness and safety of gamma knife radiosurgery (GKRS) for the treatment of intracranial dural arteriovenous fistulas (dural AVFs) over the past 10 years.

Materials and Methods:

The records of 21 patients diagnosed with dural AVFs between 2004 and 2014 and treated with GKRS were reviewed retrospectively. Complete obliteration (CO) was defined as total symptom relief plus confirmation through magnetic resonance imaging or conventional angiography.

Results:

The median follow-up was 70.5 months (range 3–136 months). Five patients underwent embolization (2 after GKRS). One patient underwent GKRS twice. The CO rate was 47%, and partial to CO rate was 88%. The complete symptom resolution rate was 77%, and all patients achieved partial to complete symptom resolution. The CO rates for Borden Type I and Type II/III dural AVFs were 66.7% and 25% (P = 0.153), respectively, and complete symptom-free rates were 76.9% and 75.0% (P = 1.000%), respectively. The median duration between initial GKRS and complete symptom resolution was 14.3 months. The median treatment to image-free durations for Borden Type I and Type II/III dural AVFs were 25.9 and 60.4 months (P = 0.028), respectively, and treatment to symptom-free durations were 10.6 and 36.7 months (P = 0.103), respectively. One patient had a recurrent hemorrhage. Two patients experienced brain edema after stereotactic radiosurgery and one patient experienced cystic formation after GKRS. The morbidity rate was 19% (four patients) and there was no mortality.

Conclusion:

Treatment with GKRS for dural AVFs offers a favorable rate of obliteration. Patients with dural AVFs that are refractory or not amenable to endovascular or surgical therapy may be safely and effectively treated using GKRS.

Early rebleeding of intracranial dural arteriovenous fistulas after an intracranial hemorrhage

BACKGROUND

The aim of this study was to evaluate the clinical and angiographic characteristics of dural arteriovenous fistulas (DAVF) presenting with intracranial hemorrhage (ICH), with a focus on early rebleeding according to the initial hemorrhage type.

METHOD

The clinical and radiologic features of 21 dAVFs that presented with intracranial hemorrhage were retrospectively reviewed. The hemorrhage type was classified as pure intraparenchymal hemorrhage (pIPH) and subarachnoid or subdural hemorrhage with IPH (non-pIPH).

RESULTS

There were 13 patients with pIPH and 8 with non-pIPH. The median follow-up period was 30 months (range, 1-116 months), and the median interval from hemorrhage to treatment was 4 days (range, 0-72 days). Rebleeding occurred in 8 (38.1%) of 21 patients. Four (50%) of eight patients with non-pIPH suffered from early rebleeding within 3 days, while there was no early rebleeding in patients with pIPH. There was a significantly higher rate of early rebleeding in the non-pIPH group (p = 0.012). Angiographically, venous ectasia (p = 0.005) and direct cortical venous drainage (dCVD) (p = 0.008) showed a significantly higher proportion in the non-pIPH group than in the pIPH group.

CONCLUSIONS

DAVFs with ICH is likely to rebleed after the first hemorrhage. Thus, early treatment can be needed in all DAVFs with ICH. In addition, DAVFs that presenting with non-pIPH and containing venous ectasia or dCVD on initial angiography may have a higher risk of early rebleeding. Therefore, cautious attention and urgent treatment are necessary for these patients.

Magnetic Resonance Spectroscopy Findings in Patients with Dural Arteriovenous Fistulas: Three Case Reports

BACKGROUND

Magnetic resonance spectroscopy (MRS) is a potentially useful modality for evaluating brain metabolites in patients with dural arteriovenous fistula (dAVF). Here we describe a different pattern of MRS-based cerebral metabolism findings in patients with dAVF.

CASE DESCRIPTIONS

We performed MRS in 3 patients with transverse sigmoid sinus dAVF associated with cortical venous reflux. In case 1, which was associated with vasogenic edema on T2-weighted magnetic resonance imaging (MRI), decreased preoperative N-acetylaspartate (NAA)/creatine (Cr) and myo-inositol (mIns)/Cr and increased lactate (Lac)/Cr ratios improved after treatment. In case 2, a decreased preoperative NAA/Cr ratio improved after treatment. These 2 patients presented with seizures. In case 3, the patient presented with headache and showed no metabolic changes on preoperative or postoperative MRS.

CONCLUSIONS

Our results suggest that patients with dAVF can be classified based on a combination of metabolic and signal changes seen on T2-weighted MRI. MRS may allow significantly expanded evaluation of the metabolic changes associated with dAVF for appropriate classification and management.