Results of combined stereotactic radiosurgery and transarterial embolization for dural arteriovenous fistulas of the transverse and sigmoid sinuses

Repeated stereotactic radiosurgery for residual intracranial dural arteriovenous fistulas

OBJECTIVE

Stereotactic radiosurgery (SRS) is widely used for the treatment of intracranial dural arteriovenous fistulas (DAVFs); however, the outcomes of repeated SRS to deal with residual DAVFs are unclear. This study assessed the benefits and potential negative consequences of repeated SRS in patients with residual DAVFs.

METHODS

This retrospective study examined all patients who underwent two SRS procedures for DAVFs in a single academic medical center between January 1998 and December 2022. Information related to patient demography, DAVFs characteristics, and clinical outcomes were obtained from medical records. The objective in this study was to obtain a preliminary overview of the results of repeated SRS for DAVFs.

RESULTS

The study cohort of 19 patients included 14 patients with non-cavernous sinus (NCS) DAVFs and 5 patients with cavernous sinus (CS) DAVFs. The NCS group included 8 patients who were categorized as low-grade (Borden grade 1) and 6 as high-grade (Borden grade 2 or 3). The median follow up duration after the second session of SRS was 37 months. Symptomatic improvement was noted in 16 patients (84.2%) and total obliteration was identified in 11 patients (57.9%). No patient suffered from intracranial hemorrhage after the repeated SRS. One patient (5.3%) experienced symptomatic radiation-induced change mandating temporary course of medical treatment.

CONCLUSIONS

Repeated SRS appears to be a safe and effective approach to deal with residual DAVFs, resulting in symptomatic improvement and complete radiologic obliteration.

Prognosis of Rotational Angiography-Based Stereotactic Radiosurgery for Dural Arteriovenous Fistulas: A Retrospective Analysis

BACKGROUND

Cerebral dural arteriovenous fistulas (DAVFs) are intracranial vascular malformations with fine, abnormal vascular architecture. High-resolution vascular imaging is vital for their visualization. Currently, rotational angiography (RA) provides the finest 3-dimensional visualization of the arteriovenous shunt with high spatial resolution; however, the efficacies of the integration of RA have never been studied in stereotactic radiosurgery (SRS) for DAVFs until now. Since 2015, our institution has integrated RA into SRS (RA-SRS) to provide more conformal planning, thereby decreasing overtreatment and undertreatment.

OBJECTIVE

To analyze the outcomes of RA-SRS for DAVFs.

METHODS

We retrospectively analyzed the outcomes of 51 patients with DAVFs and compared those of 20 DAVFs treated with RA-SRS with those of 31 DAVFs treated with conventional SRS (c-SRS).

RESULTS

The time to obliteration was shorter in the RA-SRS group (median, 15 months vs 26 months [cumulative rate, 77% vs 33% at 2 years, 77% vs 64% at 4 years]; P = .015). Multivariate Cox proportional hazards analysis demonstrated that RA-SRS (hazard ratio 2.39, 95% CI 1.13-5.05; P = .022) and the absence of cortical venous reflux (hazard ratio 2.12, 95% CI 1.06-4.25; P = .034) were significantly associated with obliteration. The cumulative 5-year post-SRS stroke-free survival rates were 95% and 97% in the RA-SRS and c-SRS groups, respectively ( P = .615). Neurological improvement tended to occur earlier in the RA-SRS group than in the c-SRS group (median time to improvement, 5 months vs 20 months, log-rank test; P = .077).

CONCLUSION

RA-based SRS may facilitate earlier fistula obliteration and may contribute to early neurological improvement.

Stereotactic Radiosurgery for Dural Arteriovenous Fistulas: A Systematic Review and Meta-Analysis and International Stereotactic Radiosurgery Society Practice Guidelines

BACKGROUND

Dural arteriovenous fistulas (dAVFs) are often treated with stereotactic radiosurgery (SRS) to achieve complete obliteration (CO), prevent future hemorrhages, and ameliorate neurological symptoms.

OBJECTIVE

To summarize outcomes after SRS for dAVFs and propose relevant practice recommendations.

METHODS

Using a PICOS/PRISMA/MOOSE protocol, we included patients with dAVFs treated with SRS and data for at least one of the outcomes of the study. Relevant outcomes were CO, symptom improvement and cure, and post-SRS hemorrhage or permanent neurological deficits (PNDs). Estimated outcome effect sizes were determined using weighted random-effects meta-analyses using DerSimonian and Laird methods. To assess potential relationships between patient and lesion characteristics and clinical outcomes, mixed-effects weighted regression models were used.

RESULTS

Across 21 published studies, we identified 705 patients with 721 dAVFs treated with SRS. The CO rate was 68.6% (95% CI 60.7%-76.5%) with symptom improvement and cure rates of 97.2% (95% CI 93.2%-100%) and 78.8% (95% CI 69.3%-88.2%), respectively. Estimated incidences of post-SRS hemorrhage and PNDs were 1.1% (95% CI 0.6%-1.6%) and 1.3% (95% CI 0.8%-1.8%), respectively. Noncavernous sinus (NCS) dAVFs were associated with lower CO (P = .03) and symptom cure rates (P = .001). Higher grade was also associated with lower symptom cure rates (P = .04), whereas previous embolization was associated with higher symptom cure rates (P = .01).

CONCLUSION

SRS for dAVFs results in CO in the majority of patients with excellent symptom improvement rates with minimal toxicity. Patients with NCS and/or higher-grade dAVFs have poorer symptom cure rates. Combined therapy with embolization and SRS is recommended when feasible for clinically aggressive dAVFs or those refractory to embolization to maximize the likelihood of symptom cure.

A Practical Grading Scale for Predicting Outcomes of Radiosurgery for Dural Arteriovenous Fistulas: JLGK 1802 Study

Background and Purpose

To assess the long-term outcomes of intracranial dural arteriovenous fistula (DAVF) treated with stereotactic radiosurgery (SRS) alone or embolization and SRS (Emb-SRS) and to develop a grading system for predicting DAVF obliteration.

Methods

This multi-institutional retrospective study included 200 patients with DAVF treated with SRS or Emb-SRS. We investigated the long-term obliteration rate and obliteration-associated factors. We developed a new grading system to estimate the obliteration rate. Additionally, we compared the outcomes of SRS and Emb-SRS by using propensity score matching.

Results

The 3- and 4-year obliteration rates were 66.3% and 78.8%, respectively. The post-SRS hemorrhage rate was 2%. In the matched cohort, the SRS and Emb-SRS groups did not differ in the rates of obliteration (P=0.54) or post-SRS hemorrhage (P=0.50). In multivariable analysis, DAVF location and cortical venous reflux (CVR) were independently associated with obliteration. The new grading system assigned 2, 1, and 0 points to DAVFs in the anterior skull base or middle fossa, DAVFs with CVR or DAVFs in the superior sagittal sinus or tentorium, and DAVFs without these factors, respectively. Using the total points, patients were stratified into the highest (0 points), intermediate (1 point), or lowest (≥2 points) obliteration rate groups that exhibited 4-year obliteration rates of 94.4%, 71.3%, and 60.4%, respectively (P<0.01).

Conclusions

SRS-based therapy achieved DAVF obliteration in more than three-quarters of the patients at 4 years of age. Our grading system can stratify the obliteration rate and may guide physicians in treatment selection.

Giant dural arteriovenous fistula in an infant

Dural arteriovenous fistulas (dAVFs) are commonly encountered by the neurosurgeon. Herein, we present a case illustration of an infant presenting with an extremely large fistula that took up a significant part of the intracranial volume. A one-month-old female presented with irritability and failure to thrive. She was the product of a 35-week pregnancy and was delivered vaginally without complications or a difficult labor. Based on the findings of magnetic resonance imaging, the diagnosis of a giant dAVF involving the transerve-sigmoid sinuses was made. The patient was scheduled for an arteriogram but died before the procedure could be performed. Such a case illustrates how large some dAVF can become and at a very early age. As in the present case, the patient was minimally symptomatic. Therefore, the time to intervention after diagnosis is thus, sometimes, critical.

Clinical and radiological response of aggressive dural arteriovenous fistula after combined glue embolization and hypofractionated helical TomoTherapy

Purpose:

We reported the clinical and radiological outcome of an aggressive dural arteriovenous fistula (DAVF) after combined glue embolization and hypofractionated helical TomoTherapy (Hypo-HT).

Materials and methods:

Eleven patients whose radiological examinations are consistent with aggressive DAVF were treated with combined glue embolization and Hypo-HT 30–36 Gy in 5–6 fractions. The dosimetric analysis, clinical response and radiological imaging obliteration rate by magnetic resonance angiography or computed tomography angiography were investigated.

Results:

There were eight males and three females with a male and female ratio of 2·67. The mean age was 51·2 years old (range 37–69). Anatomical imaging sites of disease included transverse-sigmoid sinuses (n = 7), superior sagittal sinus (n = 3) and tentorium cerebelli (n = 1). The mean pitch and MF of treatment plans were 0·273 ± 0·032 and 1·70 ± 0·31, respectively. The average size of PTV were 15·39 ± 7·74 cc whereas the Reff,PTV was 1·50 ± 0·25 cm. The average Dmax and Dmin were 37·52 ± 3·34 and 31·77 ± 2·64 Gy, respectively. HI, CI and CI50 were 0·16 ± 0·06, 1·80 ± 0·56 and 7·85 ± 4·16, respectively. The R eff,Rx and R eff,50%Rx were 1·80 ± 0·24 and 2·90 ± 0·45 cm, respectively. The R eff between 50%Rx and 100%Rx was 1·10 ± 0·28 cm on average. With a mean follow up of 28·5 months (range 9–48), the complete recovery of symptoms was found in 72·7 % (eight patients) within 2–12 months after completion Hypo-HT. Partial recovery was reported in 18·2% (two patients). No clinical response was found in 9·1% (one patient). The total radiographic obliteration rate was 27·3% (three patients), subtotal obliteration was 27·3% (three patients) and partial obliteration was 45·4% (five patients).

Conclusions:

Satisfactory clinical response of aggressive DAVF was found in all treated patients by combining glue embolization and Hypo-HT. All dosimetric parameters were acceptable. We still need an extended follow up time to assess further radiographic obliteration rate and late side effects of the treatment.

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.

Carotid-cavernous fistula from the perspective of an ophthalmologist A Review

Carotid-cavernous fistula (CCF) is an abnormal communication - vascular connection between arteries and veins in the cavernous sinus. Classification according to etiology is traumatic vs spontaneous. According to blood flow rate per high flow vs low flow fistula. According to anatomy of direct vs indirect: Direct (direct) CCF arises through direct communication between the internal carotid artery (ICA) and the cavernous sinus. Indirect CCF originates through indirect communication through the meningeal branches of ICA, external carotid artery and cavernous sinus (not directly with ICA) and Barrow type A, B, C, D division. Patients subjective complaints depend on the type of CCF. Most often it is pulsating tinnitus, synchronous with blood pulse. Typical findings include protrusion and pulsation of the eyeball, corkscrew vessels - arterialization of conjunctival and episleral vessels, increased intraocular pressure, not responding to local antiglaucomatous therapy, keratopathy a lagophthalmo, corneal ulcers. In the later untreated stages of CCF, secondary, venous stasis or central retinal vein occlusion can occur. Diagnostic procedures include B-scan and color Doppler ultrasonography, digital ophthamodynamometry, computer tomography, nuclear magnetic resonance and digital subtraction angiography. CCF can simulate orbitopathy, conjunctivitis symptoms, carotid occlusion, scleritis or cavernous sinus thrombosis. The ophthalmologist should recognize and indicate the necessary examinations in a timely manner. The therapy is ophthalmological, neuroradiological, sterotactic, surgical and conservative.

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.

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.

Venous outflow restriction as a predictor of cavernous sinus dural arteriovenous fistula obliteration after Gamma Knife surgery

OBJECTIVE

Gamma Knife surgery (GKS) obliterates 65%-87% of cavernous sinus dural arteriovenous fistulas (CSDAVFs). However, the hemodynamic effect on GKS outcomes is relatively unknown. The authors thus used the classification scheme developed by Suh et al. to explore this effect.

METHODS

The authors retrospectively (1993-2016) included 123 patients with CSDAVFs who received GKS alone at the institute and classified them as proliferative type (PT; n = 23), restrictive type (RT; n = 61), or late restrictive type (LRT; n = 39) after analyzing their pre-GKS angiography images. Treatment parameters, the presence of numerous arterial feeders, and venous drainage numbers were compared across the CSDAVF types. Patients' follow-up MR images were evaluated for the presence of complete obliteration. A Kaplan-Meier analysis was conducted to determine the correlation between CSDAVF types and outcomes.

RESULTS

The 36-month probability of complete obliteration was 74.3% for all patients, with no significant differences across types (p = 0.56). PT had the largest radiation volume (6.5 cm3, p < 0.001), the most isocenters (5, p = 0.015) and venous drainage routes (3, p < 0.001), and the lowest peripheral dose (16.6 Gy, p = 0.011) and isodose level coverage (64.3%, p = 0.006). CSDAVFs presenting with ocular patterns were less likely to be completely obliterated (hazard ratio 0.531, p = 0.009). After adjustment for age, CSDAVFs with more venous drainage routes were less likely to be completely obliterated (hazard ratio 0.784, p = 0.039).

CONCLUSIONS

GKS is an equally effective treatment option for all 3 CSDAVF types. Furthermore, the number of venous drainage routes may help in predicting treatment outcomes and making therapeutic decisions.

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.

Stereotactic Radiosurgery for Dural Arteriovenous Fistulas Involving the Transverse-Sigmoid Sinus : A Single Center Experience and Review of the Literatures

Objective

We retrospectively assessed the efficacy of stereotactic radiosurgery (SRS) for dural arteriovenous fistulas (DAVFs) involving the transverse-sigmoid sinus and analyzed the angiographic and clinical results with our 8-year experience.

Methods

Nine patients with intracranial DAVFs involving the transverse-sigmoid sinus underwent SRS using a Gamma Knife^® (Elekta Inc., Atlanta, GA, USA) between 2009 and 2016. Five patients underwent SRS for residual DAVFs after embolization and four patients were treated with SRS alone. The median target volume was 1.9 cm³ (range, 0.8–14.2) and the median radiation dose of the target was 17 Gy (range, 16–20). The median follow-up period was 37 months (range, 7–81).

Results

Pulsating tinnitus (33%) was the most common symptom. DAVFs were completely obliterated in four patients (44%) and subtotally obliterated in five (56%). Six patients (67%) showed complete recovery of symptoms or signs, and three (33%) showed incomplete recovery. One patient experienced a recurrent seizure. Adverse radiation effects after SRS occurred in one patient (11%). The total obliteration rates after SRS were 16.7%, 37.5%, and 68.7% at 1, 2, and 3 years, respectively. The median interval from SRS to total obliteration of the fistula was 31 months (range, 12–38). The rates at which the symptoms started to improve were 40% at 1 month and 80% at 2 months after SRS. Symptoms started to improve at a median of 5 weeks after SRS (range, 3–21).

Conclusion

SRS with or without embolization is a safe and effective treatment to relieve symptoms and obliterate DAVFs on the transverse-sigmoid sinus.

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.

Current status of endovascular treatment for dural arteriovenous fistula of the transverse-sigmoid sinus: A literature review

Most intracranial dural arteriovenous fistulae (DAVFs) involve the transverse-sigmoid sinus (TSS), and various types of endovascular treatment (EVT) have been involved in managing TSS DAVFs. A current, comprehensive review of the EVT of TSS DAVFs is lacking. This study used the PubMed database to perform a literature review on TSS DAVFs to increase the current understanding of this condition. For high-grade TSS DAVFs such as Borden type 3, the goal of EVT is curative treatment. However, for low-grade TSS DAVFs such as Borden type 1 and some Borden type 2 TSS DAVFs, symptom relief or elimination of cortical reflux may be sufficient. Currently, EVT has become the first-line treatment for TSS DAVFs, including transarterial embolization (TAE), transvenous embolization (TVE) or both. TAE alone and TSS balloon-assisted TAE are also commonly used. However, TVE for TSS DAVFs is recognized as the most effective treatment, including coil direct packing TSS, Onyx® (ethylene vinyl alcohol copolymer) TVE, and balloon-assisted Onyx® TVE, which are commonly applied. In addition, TSS reconstructive treatment can be an effective procedure to treat TSS DAVFs. EVT is accompanied with complications, including technique- and treatment-related complications. Although complications may occur, TSS DAVFs have an acceptable prognosis after EVT.

An Onyx tunnel: reconstructive transvenous balloon-assisted Onyx embolization for dural arteriovenous fistula of the transverse-sigmoid sinus

Transvenous embolization is an effective method for treating dural arteriovenous fistulas (DAVFs) of the transverse-sigmoid sinus (TSS). However, in cases of complicated DAVFs, it is difficult to preserve the patency of the dural sinus. The authors describe the technical details of a new reconstructive technique using transvenous balloon-assisted Onyx embolization as another treatment option in a patient with an extensive and complex DAVF of the left TSS. A microcatheter and compliant balloon catheter were navigated into the left internal jugular vein and placed at the distal end of the DAVF in the transverse sinus. The microcatheter was placed between the vessel wall of the TSS and the balloon. After the balloon was fully inflated, Onyx-18 was injected at the periphery of the balloon in a slow, controlled, progressive, stepwise manner; the balloon and microcatheter were simultaneously withdrawn toward the sigmoid sinus, with Onyx encompassing the entirety of the complex DAVF. The Onyx refluxed into multiple arterial feeders in a distal-to-proximal step-by-step manner, ultimately resulting in an Onyx tunnel. The final angiography study revealed complete obliteration of the DAVF and patency of the TSS. The Onyx tunnel, or reconstructive transvenous balloon-assisted Onyx embolization technique, may be an effective treatment option for large, complex DAVFs of the TSS. This technique may provide another option to facilitate the complete obliteration of the DAVF while preserving the functional sinus.

Mastoid Epidermoid Tumor and Associated Dural Arteriovenous Fistula with Venous Sinus Occlusion

BACKGROUND

Dural arteriovenous fistula (DAVF) is an abnormal vascular connection between arterial and venous channels within dura mater. Although DAVFs have been linked to other types of intracranial tumors, this is the first case reporting the association between DAVF and an epidermoid tumor.

CASE DESCRIPTION

A middle-aged patient with chronic headache presented with Borden type II DAVF draining into the right transverse sigmoid junction and was also found to have an epidermoid tumor over the right mastoid. The patient underwent staged embolization of the fistula through both transvenous and transarterial routes. Continuous intraoperative venous pressure monitoring confirmed marked reduction in intracranial venous pressure, and the patient's symptoms completely resolved. However, the fistula still remained. The residual DAVF was then surgically disconnected, and the epidermoid tumor was resected in the same procedure.

CONCLUSIONS

This case demonstrates a DAVF can be associated with an epidermoid tumor. Tumor can compromise the venous outflow, which can then lead to intracranial venous hypertension and development of the DAVF. Venous pressure monitoring offers an objective method to verify resolution of venous hypertension, which might correlate with resolution of clinical symptoms.

Application of Time-Resolved 3D Digital Subtraction Angiography to Plan Cerebral Arteriovenous Malformation Radiosurgery

BACKGROUND AND PURPOSE

Time-resolved 3D-DSA (4D-DSA) enables viewing vasculature from any desired angle and time frame. We investigated whether these advantages may facilitate treatment planning and the feasibility of using 4D-DSA as a single imaging technique in AVM/dural arteriovenous fistula radiosurgery.

MATERIALS AND METHODS

Twenty consecutive patients (8 dural arteriovenous fistulas and 12 AVMs; 13 men and 7 women; mean age, 45 years; range, 18-64 years) who were scheduled for gamma knife radiosurgery were recruited (November 2014 to October 2015). An optimal volume of reconstructed time-resolved 3D volumes that defines the AVM nidus/dural arteriovenous fistula was sliced into 2D-CT-like images. The original radiosurgery treatment plan was overlaid retrospectively. The registration errors of stereotactic 4D-DSA were compared with those of integrated stereotactic imaging. AVM/dural arteriovenous fistula volumes were contoured, and disjoint and conjoint components were identified. The Wilcoxon signed rank test and the Wilcoxon rank sum test were adopted to evaluate registration errors and contoured volumes of stereotactic 4D-DSA and integration of stereotactic MR imaging and stereotactic 2D-DSA.

RESULTS

Sixteen of 20 patients were successfully registered in Advanced Leksell GammaPlan Program. The registration error of stereotactic 4D-DSA was smaller than that of integrated stereotactic imaging (P = .0009). The contoured AVM volume of 4D-DSA was smaller than that contoured on the integration of MR imaging and 2D-DSA, while major inconsistencies existed in cases of dural arteriovenous fistula (P = .042 and 0.039, respectively, for measurements conducted by 2 authors).

CONCLUSIONS

Implementation of stereotactic 4D-DSA data for gamma knife radiosurgery for brain AVM/dural arteriovenous fistula is feasible. The ability of 4D-DSA to demonstrate vascular morphology and hemodynamics in 4 dimensions potentially reduces the target volumes of irradiation in vascular radiosurgery.

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.

Transarterial venous sinus occlusion of dural arteriovenous fistulas using ONYX

PURPOSE

The purpose of this article is to present a case series of transarterial venous sinus occlusion for dural arteriovenous fistulas (DAVFs) of the transverse and sigmoid sinuses.

MATERIALS AND METHODS

From 2006 to 2012, 11 patients with DAVF of the transverse and sigmoid sinuses were treated with transarterial closure of the affected venous sinus using ethylene vinyl alcohol copolymer (ONYX). The consecutive retrospective cohort included six female and five male patients with an age range of 30-79. Patients presented with stroke, intracranial hemorrhage, seizure, headache, focal neurologic deficit or cognitive change. Lesions were categorized as Cognard II a + b (n = 5) or Cognard II b (n = 6). Four of this latter group consisted of isolated sinus segments. Selection criteria for dural sinus occlusion included direct multi-hole fistulas involving a broad surface in length or circumference of the sinus wall. External carotid artery (ECA) branches were directly embolized when considered safe. High-risk arterial supply from ICA, PICA, AICA or ECA cranial nerve branches were closed via retrograde approach during sinus occlusion.

RESULTS

DAVF closure was accomplished in all 11 patients with a total of 17 embolization procedures using ONYX. High-risk arterial collaterals were closed via artery-artery or artery-sinus-artery embolization. The vein of Labbe was spared in the four cases with initial antegrade flow. No neurologic complications occurred, and DAVF closures were durable on three-month angiography.

CONCLUSION

Transarterial closure of the transverse and sigmoid sinuses.

The efficacy of gamma knife radiosurgery alone as a primary treatment for intracranial dural arteriovenous fistulas

BACKGROUND

The application of gamma knife radiosurgery (GKRS) alone has been expanded for dural arteriovenous fistulas (DAVFs). However, a standardized protocol delineating the appropriate circumstances for GKRS alone in cases of DAVF has yet to be determined. The purpose of this study was to report a single center's treatment algorithm for GKRS alone as a primary treatment for intracranial DAVFs and assess related clinical and radiological data.

METHOD

Among 31 DAVF patients treated according to our institute's treatment algorithm between February 2009 and November 2014, 20 patients underwent GKRS alone. DAVF patients treated with GKRS alone fell in two main subgroups: DAVF patients without cortical venous reflux (CVR) but with symptoms (n = 8) and DAVF patients with CVR but without a high bleeding risk (defined as CVR with aggressive symptoms including hemorrhage or non-hemorrhagic neurological deficit, n = 11). One DAVF patient with a high bleeding risk had GKRS alone because of difficult endovascular access. Mean radiation volume was 4.8 cc (range, 0.7-14.2 cc), and mean maximal dose was 33.5 Gy (range, 28-38 Gy).

RESULTS

At mean follow-up of 29.1 months (range, 8-69 months), radiological findings demonstrated complete cures in 18 patients (90 %) and subtotal cures in 2 patients (10 %). One patient had a transient complication, but no neurologic sign. All symptomatic patients showed complete resolution.

CONCLUSIONS

Our treatment algorithm showed GKRS alone may serve as a primary treatment for patients with DAVFs regardless of location and presence of CVR, unless there is a high bleeding risk. However, a multicenter, prospective study is necessary to generalize our treatment algorithm.

Stereotactic radiosurgery for intracranial dural arteriovenous fistulas: a systematic review

OBJECT

The goal of this study was to evaluate the obliteration rate of intracranial dural arteriovenous fistulas (DAVFs) in patients treated with stereotactic radiosurgery (SRS), and to compare obliteration rates between cavernous sinus (CS) and noncavernous sinus (NCS) DAVFs, and between DAVFs with and without cortical venous drainage (CVD).

METHODS

A systematic literature review was performed using PubMed. The CS DAVFs and the NCS DAVFs were categorized using the Barrow and Borden classification systems, respectively. The DAVFs were also categorized by location and by the presence of CVD. Statistical analyses of pooled data were conducted to assess complete obliteration rates in CS and NCS DAVFs, and in DAVFs with and without CVD.

RESULTS

Nineteen studies were included, comprising 729 patients harboring 743 DAVFs treated with SRS. The mean obliteration rate was 63% (95% CI 52.4%–73.6%). Complete obliteration for CS and NCS DAVFs was achieved in 73% and 58% of patients, respectively. No significant difference in obliteration rates between CS and NCS DAVFs was found (OR 1.72, 95% CI 0.66–4.46; p = 0.27). Complete obliteration in DAVFs with and without CVD was observed in 56% and 75% of patients, respectively. A significantly higher obliteration rate was observed in DAVFs without CVD compared with DAVFs with CVD (OR 2.37, 95% CI 1.07–5.28; p = 0.03).

CONCLUSIONS

Treatment with SRS offers favorable rates of DAVF obliteration with low complication rates. Patients harboring DAVFs that are refractory or not amenable to endovascular or surgical therapy may be safely and effectively treated using SRS.

Arterial Onyx Embolisation of Intracranial DAVFs with Cortical Venous Drainage

Purpose:

To present our experience with the endovascular management of intracranial dural arteriovenous fistulas with direct cortical venous drainage by trans-arterial embolisation using Onyx.

Materials & Methods:

Between January 2004 and April 2008, 12 consecutive high grade intracranial dural arteriovenous fistulas (Cognard type III (eight patients) or IV (three patients)) were treated by trans-arterial embolisation with Onyx. The majority of cases were treated by Onyx embolisation alone. One case had additional embolisation with n-butyl-2-cyanoacrylate at the same session. Imaging follow-up was obtained in all but one patient (mean 3.6 months).

Results:

Nine patients had a technical success at the end of the embolisation procedure with complete angiographic exclusion of the fistula. Two patients had a small residual fistula at the end of embolisation, one of which had residual mild cortical venous drainage. Both were stable at follow-up angiography. One patient had a residual fistula supplied by the ophthalmic artery, which was thought to be unsafe to embolise and was sent for surgery, which was curative. In one patient the microcatheter ruptured, with a fragment of the distal microcatheter left in the occipital artery. No clinical complications were observed in this series at clinical follow-up (mean 3.3 months). Two patients were noted to have significant radiation dose.

Conclusion:

Endovascular management of intracranial dural arteriovenous fistulas with direct venous cortical drainage by trans-arterial Onyx embolisation is a safe and effective treatment according to our experience. Fluoroscopy times and radiation dose may be a concern.

Gamma Knife radiosurgery for the management of intracranial dural arteriovenous fistulas

BACKGROUND

This report presents our 15-year experience with Gamma Knife radiosurgery (GKS) for the treatment of 321 patients with dural arteriovenous fistulas (DAVFs) in different locations.

METHODS

The most common locations of DAVFs were the cavernous sinus (206 cases) and transverse-sigmoid sinus (72 cases), which together accounted for 86.6 % of cases. In all, 54 patients had undergone embolization or surgery prior to radiosurgery, and the other patients underwent GKS as the primary treatment. During GKS, radiation was confined to the involved sinus wall, which was considered the true nidus of the DAVF. Target volume ranged from 0.8 to 52 cm(3). Marginal and maximum doses to the nidus ranged from 14 to 25 Gy and from 25 to 36 Gy, respectively.

RESULTS

The mean follow-up time was 28 months (range 2-149 months). In 264 of 321 patients (82 %) available for follow-up study, 173 (66 %) showed complete obliteration of DAVFs with symptomatic resolution, 87 (33 %) had partial obliteration, 2 (0.8 %) had stationary status, 1 (0.4 %) had progression, and 1 (0.4 %) died from a new hemorrhagic episode. Complications were found in only two (0.8 %) patients, one with venous hemorrhage and one with focal brain edema after GKS.

CONCLUSIONS

GKS is a safe, effective treatment for DAVFs. It provides a minimally invasive therapeutic option for patients who harbor less-aggressive DAVFs but who suffer from intolerable clinical symptoms. For some aggressive DAVFs with extensive venous hypertension or hemorrhage, multimodal treatment with combined embolization or surgery is necessary.

Endovascular treatment of cerebral dural and pial arteriovenous fistulas

Dural arteriovenous fistulas (DAVFs) are arteriovenous shunts from a dural arterial supply to a dural venous channel, typically supplied by pachymeningeal arteries and located near a major venous sinus. Pial arteriovenous fistulas (PAVFs) are composed of one or more arterial feeders draining into a single vein in the absence of an intervening nidus. Fistulas manifesting features of high risk for rupture should be treated aggressively, the spectrum of treatment varies from endovascular, surgical resection, and stereotactic radiosurgery. This article describes the natural history, clinical presentation, and treatment of dural and pial fistulas, with emphasis on endovascular treatment.

[Intracranial dural arteriovenous fistulae. Experience after 81 cases and literature review]

OBJECTIVES

To analyse the clinical, radiological and therapeutic variables of intracranial dural arteriovenous fistulae (DAVF) treated at our institution, and to assess the validity of the Borden and Cognard classifications and their correlation with the presenting symptoms.

MATERIAL AND METHODS

The DAVF identified were retrospectively analysed. They were classified according to their location, drainage pattern and the Borden and Cognard classifications. We recorded the different treatments, their complications and efficacy.

RESULTS

There were 81DAVF identified between 1975 and 2012. The cavernous sinus (CS) location was the most frequent one. The Borden and Cognard classifications showed an interobserver Kappa index of 0.72 and 0.76 respectively. The odds ratio of aggressive presentation in the presence of cortical venous drainage (CVD) was 19.3 (2.8-132.4). No location, once adjusted by venous drainage pattern, showed significant association with an aggressive presentation. Endovascular transarterial treatment of cavernous sinus DAVF achieved symptomatic improvement of 78%, with a complication rate of 5%. The DAVF of non-CS locations, with CVD, treated surgically were angiographically shown cured in 100% of the cases, with no treatment-related complications.

CONCLUSIONS

The presence of CVD was significantly associated with aggressive presentations. The Borden and Cognard classifications showed little interobserver variability. Endovascular treatment for CS DAVF is safe and relatively effective. Surgical treatment of non-CS DAVF with CVD is safe, effective and the first choice treatment in our environment.

Characteristics and long-term outcome of 251 patients with dural arteriovenous fistulas in a defined population

OBJECT

Management of dural arteriovenous fistulas (DAVFs) has changed during the last decades due to increased knowledge of their pathophysiology and natural history as well as advances in treatment modalities. The authors describe the characteristics and long-term outcome of a large consecutive series of patients with DAVFs.

METHODS

Altogether 251 patients with 261 DAVFs were treated in 2 of the 5 neurosurgery departments at Helsinki and Kuopio University Hospitals between 1944 and 2006. Clinical data and radiological examinations were reviewed to assess patients' overall long-term clinical outcome.

RESULTS

The detection rate of DAVFs increased markedly in the 1970s and again in the 1990s when digital subtraction angiography was introduced. The incidence of DAVFs in a defined southern Finnish population was 0.51 per 100,000 individuals per year, which represents 32% of all the brain arteriovenous malformations. In the early part of the series, DAVFs were treated by proximal ligation of the feeding arteries. Later, most of the patients underwent preoperative embolization and subsequent craniotomy, and since 2000 stereotactic radiosurgery has been increasingly used in the treatment of DAVFs. Fifty-nine percent of the 261 fistulas were totally occluded. Treatment-related major complications were seen in 21 patients.

CONCLUSIONS

The advances in diagnostic methods (digital subtraction angiography, CT, and MRI) increased the detection rate of DAVFs, and as treatment modalities developed, the results of treatment and outcome of patients markedly improved with the introduction of endovascular techniques and stereotactic radiosurgery. Microsurgery is of limited use in DAVFs resistant to other treatment modalities.

Stereotactic radiosurgery for cerebral dural arteriovenous fistulas

Object

Given the feasibility of curative surgical and endovascular therapy for cerebral dural arteriovenous fistulas (DAVFs), there is a relative paucity of radiosurgical series for these lesions as compared with their arteriovenous malformation counterparts.

Methods

The authors reviewed records of 56 patients with 70 cerebral DAVFs treated at their institution over the past 6 years. Ten DAVFs (14%) in 9 patients were treated with stereotactic radiosurgery (SRS), with follow-up obtained for 8 patients with 9 DAVFs. They combined their results with those obtained from a comprehensive review of the literature, focusing on obliteration rates, post-SRS hemorrhage rates, and other complications.

Results

In the authors' group of 9 DAVFs, angiographic obliteration was seen in 8 cases (89%), and no post-SRS hemorrhage or complications were observed after a mean follow-up of 2.9 years. Combining the results in these cases with data obtained from their review of the literature, they found 558 DAVFs treated with SRS across 14 series. The overall obliteration rate was 71%; transient worsening occurred in 9.1% of patients, permanent worsening in 2.4% (including 1 death, 0.2% of cases), and post-SRS hemorrhage occurred in 1.6% of cases (4.8% of those with cortical venous drainage [CVD]). The obliteration rate for cavernous DAVFs was 84%, whereas the rates for transversesigmoid and for tentorial DAVFs were 58% and 59%, respectively (adjusted p values, pcav,TS = 1.98 × 10−4, pcav,tent = 0.032). Obliteration rates were greater for DAVFs without CVD (80%, compared with 60% for those with CVD, p = 7.59 × 10−4). Both transient worsening and permanent worsening were less common in patients without CVD than in those with CVD (3.4% vs 7.3% for transient worsening and 0.9% vs 2.4% for permanent worsening).

Conclusions

Stereotactic radiosurgery with or without adjunctive embolization is an effective therapy for DAVFs that are not amenable to surgical or endovascular monotherapy. It is best suited for lesions without CVD and for cavernous DAVFs.

Stereotactic radiosurgery of cranial arteriovenous malformations and dural arteriovenous fistulas

Cranial arteriovenous malformations (AVM) and cranial dural arteriovenous fistulas (AVF) carry a significant risk of morbidity and mortality when they hemorrhage. Current treatment options include surgery, embolization, radiosurgery, or a combination of these treatments. Radiosurgery is thought to reduce the risk hemorrhage in AVMs and AVFs by obliterating of the nidus of abnormal vasculature over the course of 2 to 3 years. Success in treating AVMs is variable depending on the volume of the lesion, the radiation dose, and the pattern of vascular supply and drainage. This article discusses the considerations for selecting radiosurgery as a treatment modality in patients who present with AVMs and AVFs.

The limitations and risks of transarterial Onyx injections in the treatment of grade I and II DAVFs

BACKGROUND AND OBJECTIVE

Embolization of grade III-V intracranial DAVFs using Onyx is feasible with promising results, indicating stability at the time of mid-term follow-up. This article is to evaluate the role of transarterial Onyx embolization in the treatment of grade I and II intracranial dural arteriovenous fistulas (DAVFs), including its limitations and risks.

METHODS

We retrospectively studied consecutive 26 patients (8 women and 18 men) treated for an grade I and II intracranial DAVF since 2006 in whom a transarterial approach was attempted with Onyx-18 embolization. There were 18 transverse-sigmoid sinus, 4 cavernous sinus, 2 superior sagittal sinus, 1 inferior petrosal sinus and 1 intradiploic fistulas. Five fistulas were Type I, 8 were Type IIa, and 13 were Type IIa+b, according to the Cognard classification. The mean clinical follow-up period was 15.6 months.

RESULTS

Anatomic cure was proven in 13 patients (50%) and clinical cure was obtained in 17 cases (65.4%). These 13 cures were achieved after a single procedure. All these 13 patients underwent a follow-up angiography, which has confirmed the complete cure. Partial occlusion was obtained in 13 patients. Complications were as follows: 2 cardiac Onyx migration, 2 reflexive bradyarrythmia, 1 transient visual hallucination, 2 transient fifth nerve palsies and 1 permanent seventh nerve palsy in inferior petrosal sinus DAVF.

CONCLUSIONS

Based on this experience, grade I and II intracranial DAVFs may be treated with transarterial Onyx embolization to reduce the shunted blood flow and to facilitate subsequent transvenous embolization or surgery.

Multidisciplinary treatment of a large cerebral dural arteriovenous fistula using embolization, surgery, and radiosurgery

Dural arteriovenous fistulae are rare lesions composed of abnormal connections between meningeal arteries and the dural sinuses or lepto-meningeal veins. Treatment is challenging because of the small size and wide distribution of the myriad sites of fistulous connection. We present a case of a dural arteriovenous fistula presenting with visual deterioration, pulsatile tinnitus, and intracranial hypertension that was successfully treated with a multidisciplinary approach combining angiographic, surgical, and radiosurgical intervention. This is one of the largest of these formidable lesions treated in this fashion that has been reported.

Selection of treatment modalities or observation of dural arteriovenous fistulas

Cranial dural arteriovenous fistulas (DAVFs) represent an important class of cranial vascular lesions. The clinical significance of these lesions is highly dependent on the pattern of venous drainage, with cortical venous reflux being an important marker of an aggressive, high-risk fistula. For asymptomatic benign fistulas, conservative management, consisting of observation with follow-up, is a reasonable option. For symptomatic benign fistulas or aggressive fistulas, treatment is recommended. A variety of treatment modalities are available for DAVF management, including endovascular techniques, open surgery, and radiosurgery. A multimodality approach is often warranted and can offer improved chances of achieving a cure.

Intracranial dural arteriovenous fistulas: A Review

Dural arteriovenous fistulas are fistulas connecting the branches of dural arteries to dural veins or a venous sinus. Digital subtraction angiography remains the gold standard for diagnosing these fistulas. Endovascular treatment is one of the first line options available for their management. This review article reviews the etiopathogenesis, natural history, common classification systems and various available treatment options.

Stereotactic radiosurgery with or without embolization for intracranial dural arteriovenous fistulas

BACKGROUND

Treatment options for dural arteriovenous fistulas (DAVFs) have expanded with the application of stereotactic radiosurgery (SRS).

OBJECTIVE

To assess the role of SRS with or without embolization, we reviewed our entire DAVF experience.

METHODS

Between 1991 and 2006, 40 patients with 44 DAVFs underwent Gamma knife SRS. Twenty-eight patients had upfront SRS before or after embolization and 12 patients underwent delayed SRS for recurrent or residual DAVFs after initial embolization. The median patient age was 60 years (range, 29-90). DAVFs were diagnosed in 7 patients after they sustained an intracranial hemorrhage. The median SRS target volume was 2.0 mL (range, 0.2-8.2 mL) and the median marginal dose was 21.0 Gy (range, 15-25 Gy).

RESULTS

At a median follow-up of 45 months (range, 23-116 mo), a total of 28 patients (harboring 32 DAVFs) had obliteration confirmed by imaging. We found a 83% obliteration rate in patients who had upfront SRS with embolization and a 67% obliteration rate in patients who only had SRS. One patient died of an intracerebral hemorrhage 2 months after SRS. Cavernous carotid fistulas were associated with higher rates of occlusion (P = .012) and symptom improvement (P = .010) than were transverse-sigmoid sinus-related fistulas.

CONCLUSION

When upfront SRS is possible in conjunction with embolization, successful DAVF obliteration is possible in most patients, especially those with carotid cavernous fistulas. SRS should target the entire fistula regardless of whether it precedes or follows embolization. In selected patients with a small-volume, low-risk DAVF, SRS alone is an effective treatment option in most patients.

Microsurgery can cure most intracranial dural arteriovenous fistulae of the sinus and non-sinus type

There is consensus that intracranial dural arteriovenous fistulae (dAVF) with direct (non-sinus-type) or indirect (sinus-type) retrograde filling of a leptomeningeal vein should be treated due to the high risk of neurological deficits and hemorrhage. No consensus exists on treatment modality (surgery and/or embolization) and, if surgery is performed, on the best surgical strategy. This series aims to evaluate the role of surgery in the management of aggressive dAVFs. Forty-two patients underwent surgery. Opening and packing the sinus with thrombogenic material was performed in 9 of the 12 sinus-type dAVFs. In two sinus-type fistulae of the cavernous sinus and 1 of the torcular, microsurgery was used as prerequisite for subsequent embolization by providing access to the sinus. In the 30 non-sinus-type dAVFs, surgery consisted of interruption of the draining vein at the intradural entry point. In 41 patients undergoing 43 operations, elimination of the dAVF was achieved (97.6%). In one case, a minimal venous drainage persisted after surgery. The transient surgical morbidity was 11.9% (n = 5) and the permanent surgical morbidity 7.1% (n = 3). Our surgical strategy was to focus on the arterialized leptomeningeal vein in the non-sinus-type and on the arterialized sinus segment in the sinus-type dAVFs allowing us to obliterate all but one dAVF with a low morbidity rate. We therefore propose that microsurgery should be considered early in the treatment of both types of aggressive dAVFs. In selected cases of cavernous sinus dAVFs, the role of microsurgery is reduced to that of an adjunct to endovascular therapy.

Treatment Strategy Based on Multimodal Management Outcome of Cavernous Sinus Dural Arteriovenous Fistula (CSDAVF)

Purpose

Angiographic finding including venous drainage pattern should be correlated to the presenting symptom pattern (SxP) in CSDAVF. We present outcome of CSDAVF management and suggest a strategy according to SxP and type of treatment based on our experience.

Materials and Methods

We evaluated SxP, angiographic type (proliferative, restrictive or late restrictive), mode of treatment (embolization, Gamma Knife Radiation (GKR) or conservative management), mode of embolization (transarterial or transvenous), and final clinical status (cure, improvement, aggravation or no change). Ninety consecutive patients were included from a prospective database. The mean follow-up was 17 months. We compared the outcomes according to SxP, angiographic type, mode of treatment, and embolization using the chi-square or Fisher's exact test.

Results

Ninety patients with 34 proliferative, 40 restrictive, and 16 late restrictive types of CSDAVF were treated by embolization (n = 63), GKR (n = 7), and conservative management (n = 20). Cure or improvement was 91% after embolization, 88% after conservative management, and 72% after GKR. Following embolization, 100% of 24 proliferative types, 87% of 30 restrictive types, and 90% of 10 late restrictive types were cured or improved. Cure or improvement after transvenous embolization was 98% (43/44) compared with 88% (15/17) after transarterial embolization (p = 0.003).

Conclusion

Various factors of SxP, angiographic type, and mode of treatment should be considered in order to obtain a more favorable outcome for patients with CSDAVF. Embolization via venous approach tended to result in a more complete cure than that via arterial approach.

Multimodality treatment of intracranial dural arteriovenous fistulas in the Onyx era: a single center experience

BACKGROUND

The results of treatment of intracranial dural arteriovenous fistulas (DAVFs) since Onyx became available as an embolic agent at our institution is reported. An algorithm is presented for treatment of DAVFs with Onyx, and the role of endovascular transvenous, surgical, and radiosurgical approaches are presented.

METHODS

Thirty-two patients with DAVFs treated between November 2005 and November 2008 by endovascular embolization, surgery, or radiosurgery were identified by a retrospective chart review. Treatment strategies were based on the location or complexity of the fistula and the patient's clinical status. Data collected included DAVF characteristics, obliteration rates, complications, and outcomes. The results were analyzed and correlated with the treatment modality.

RESULTS

Presenting symptoms were as follows: hemorrhage (n = 12 patients), headaches (n = 12), tinnitus (n = 5), orbital symptoms (n = 7), and seizures (n = 1). Thirty patients were treated by endovascular embolization (transarterial only with Onyx-21, transvenous only with platinum coils-6, transarterial [Onyx] and transvenous [coils]-3). Five patients (4 after incomplete/failed embolization) had surgical excision of the fistula. Three patients were treated with Gamma Knife radiosurgery (primary-1, 2 after incomplete/failed embolization). The locations of the fistulas were transverse sigmoid (10 patients), petrotentorial (7 patients), indirect carotid cavernous fistula (7 patients), parasagittal/falcine (3 patients), middle fossa dura (3 patients), torcula (1 patient), and anterior fossa dura (1 patient). The distribution of patients according to Borden classification was I-6, II-13, and III-13. Complete obliteration of the fistula was achieved in 26/32 (81%) patients after multimodal treatment. All surgical cases had complete obliteration. In the high-risk group with cortical venous reflux, 23/26 (89%) patients were cured. Endovascular complications included a stuck microcatheter tip with fracture of the tip in two patients and cranial nerves V and VII palsies in one patient. At last follow-up (range 1-36 months), 24 patients had modified Rankin score of 0-2, 5 patients had modified Rankin score of 3-5, and 3 patients were dead. Two patients died during admission due to the insult of the hemorrhage, and one died after an accidental fall with subsequent traumatic subdural hematoma.

CONCLUSIONS

Multimodality treatment of DAVFs has high success rates for cure at our center. Transarterial embolization with Onyx has become the primary treatment for intracranial DAVFs at our center and is associated with high safety profile and efficacy. Transvenous coil embolization is still preferred in DAVFs with supply from arterial branches supplying cranial nerves, predominant internal carotid artery feeders and potential extracranial-intracranial collateral anastomosis. In our series, patients with incompletely treated DAVFs were treated with surgery and those with partially treated type I fistulas had radiosurgery for palliation.

Tentorial dural fistula with giant venous ampulae treated with embolisation and surgery. A case report

Tentorial dural arteriovenous fistulas are rare and complex lesions in deep locations with unusual vascular anatomy and critical surrounding neuroanatomy. A rare case presenting a complex fistula with a giant venous draining ampulae, causing headaches and visual troubles is presented. We describe the case of a 52-year-old woman admitted in our department for headaches and visual troubles. Magnetic resonance imaging and cerebral angiography showed a tentorial dural arteriovenous fistula draining in a giant tentorial venous ampulae and leptomeningeal veins. The patient was embolised via an arterial route with a good clinical and radiological result. However, 4 days later she presented a sudden change of her clinical status with coma, left hemiparesis and a right midriasis. The cerebral computed tomography scan showed a huge occipital haemorrhagic mass and a severe cerebral oedema. An emergent surgical procedure was decided realising evacuation of the occipital haematoma and a complete resection of the giant venous ampoule. The neck of the ampulae was sutured and clipped at its dural entrance. Postoperatively a new embolisation was realised because of persistent of a small dural fistulae with occipital leptomeningeal drainage. The patient recovered rapidly with only a residual hemianopsy. Treatment of dural AV malformation represent a serious challenge. Our report describes an unusual case of a tentorial dural complex fistula treated by an endovascular procedure with secondary clinical aggravation that needed emergent surgical therapy. Even in a case for good immediate radiological result after endovascular procedure, dural arteriovenous fistulas with giant venous ampulae and important venous engorgement, need closed follow-up, because of the possibility of aggravation secondary to venous thrombosis and haemorrhage. Treatment and patophysiology of the aggravation mechanism are discussed.

Transverse-sigmoid sinus dural arteriovenous fistulae

Transverse-sigmoid sinus dural arteriovenous fistulae are abnormal arteriovenous communications within the dural wall of the transverse-sigmoid sinuses. They present with a variety of clinical features, ranging from benign bruits to intracranial hemorrhage and neurologic deficits. The presentation and natural history of these fistulae are largely determined by the pattern of venous drainage. Knowledge of natural history and careful study of the angioarchitecture by angiography is therefore mandatory for correct management of these lesions. In this review, anatomy and pathology, principles of management, and the various factors that influence treatment decisions are discussed, with a focus on endovascular therapy. Indications for endovascular treatment, therapeutic goals, approaches, and techniques are reviewed. The role of surgical treatment is also briefly discussed.