Stereotactic radiosurgery for the treatment of dural arteriovenous fistulas involving the transverse-sigmoid sinus

Secondary ocular hypertension due to tentorial dural arteriovenous fistula: a case report

BACKGROUND

Tentorial dural arteriovenous fistulas (TDAVFs) are abnormal shunts between meningeal arteries and the intradural venous system located in the tentorial dura mater, which typically manifest with haemorrhage or progressive neurological disorders. TDAVFs with pure ocular presentation have been rarely reported.

CASE PRESENTATIONS

The case of a 56-year-old man presented with unilateral eye redness, proptosis and elevated intraocular pressure was reported herein, which was caused by a TDAVF. The fistula was fed by the left posterior cerebral artery and posterior meningeal artery. The drainage was into the basal vein and internal cerebral veins, which led the arterial blood flow forward to the left superior ophthalmic vein directly. The redundant blood flow caused the rise of episcleral venous pressure, leading to the clinical presentations. Gamma knife radiosurgery was performed then considering the delicate vascular structure and its deep location. The corkscrew hyperaemia was gradually alleviated after the surgery, but the intraocular pressure remained elevated at follow-ups.

CONCLUSION

Dural arteriovenous fistulas which are not directly connected to cavernous sinus could cause ocular presentations like proptosis, eye redness and ocular hypertension.

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.

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.

Impaired intrinsic functional connectivity among medial temporal lobe and sub-regions related to memory deficits in intracranial dural arteriovenous fistula

PURPOSE

The functional changes concerning memory deficits in dural arteriovenous fistula (dAVF) brain are inadequately understood. This study aimed to understand the functional connectivity alterations of brain regions widely affirmed for explicit and implicit memory functions in dAVF patients (DP) and look into the frequency effects of the altered functional networks.

METHODS

Resting-state functional magnetic resonance imaging (rsfMRI) analysis was done in the memory-associated regions of 30 DP and 30 healthy controls (HC). Frequency decomposition was used to determine potential frequency-dependent functional connectivity changes. They underwent neuropsychological tests and were correlated with changes in memory networks compared with HC.

RESULTS

The results showed weaker functional connectivity among the medial temporal lobe and sub-regions in DP suggestive of dysfunction of explicit and implicit memory functions, which corroborated with the positive correlation between memory scores and hippocampal-parahippocampal connectivity of DP, along with a significant group difference of lower memory and cognitive performance in DP assessed by neuropsychological tests. A frequency-dependent study of the altered rsFC revealed lower functional connectivity strength and impaired neural coupling manifested at some sub-band frequencies indicative of disturbed cortical rhythm in DP.

CONCLUSION

This pilot study gives insights into significant intrinsic functional connectivity changes in the memory regions of the dAVF brain. The results may have clinical implications in the choice of interventional management of dAVF and can impact clinical decision making for realizable prevention of progressive memory impairment and irreversible brain damage in such patients.

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 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.

Endovascular Treatment of Dural Arteriovenous Fistulas of the Anterior or Posterior Condylar Vein : A Cadaveric and Clinical Study and Literature Review

Dural arteriovenous fistulas (DAVF) involving the anterior and posterior condylar vein at the skull base are rare but important to recognize. Due to the highly variable anatomy of the venous system of the skull base, detailed anatomical knowledge is essential for correct diagnosis and appropriate treatment of these lesions. In this report we review the normal anatomy of the condylar veins and describe rare and, to our knowledge, not previously reported anatomical variants. We also highlight the treatment modalities for these lesions with focus on the endovascular transvenous occlusion based on four consecutive cases from our center.

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.

Stereotactic radiosurgery for intracranial dural arteriovenous fistulas: its clinical and angiographic perspectives

BACKGROUND

To assess the efficacy of stereotactic radiosurgery (SRS) for intracranial dural arteriovenous fistulas (DAVFs), the authors retrospectively reviewed our 7-year experience. We evaluated the obliteration rate, improvement in clinical symptoms, and complications.

METHODS

Thirty patients with DAVF underwent SRS using a Gamma Knife between 2009 and 2015. Twenty-three patients were treated with SRS alone, and seven patients underwent SRS for residual or recurrent DAVFs after embolization or surgery. Chemosis, diplopia, and pulsating tinnitus were the most common symptoms. Median target volume was 2.9 cm³ (range, 0.8-13.6 cm³), and median radiation dose to the target was 17 Gy (range, 12-20 Gy). Median follow-up period was 33 months (range, 6-82 months).

RESULTS

At the last neuroimaging follow-up, DAVFs were totally obliterated in 23 patients (77%) and subtotally in 7 (23%). At the last clinical follow-up, 21 patients (70%) showed complete recovery, and 9 (30%) showed incomplete recovery in symptoms or signs. None experienced worsening symptoms or signs. Asymptomatic perilesional edema after SRS occurred in one patient (3%). Total obliteration rates after SRS were 43% at 1 year, 79% at 2 years, and 95% at 5 years. Improvement rates of neurological function after SRS were 12% at 1 month, 52% at 2 months, 72% at 3 months, and 96% at 6 months. A multivariate analysis revealed that Borden type 1 (p = 0.019, hazard ratio, 3.254, 95% confidence interval, 1.216-8.707) was significantly associated with symptom improvement.

CONCLUSIONS

SRS for intracranial DAVFs provided a high obliteration rate and a relatively low risk of radiation-induced complications. In selected benign cases without cortical venous drainage, SRS is a safe and effective treatment for symptom relief and fistula obliteration, even though the time course of improvement is longer than those of embolization and surgery.

Stereotactic Radiosurgery for Dural Carotid Cavernous Sinus Fistulas

OBJECTIVE

We reviewed our 7-year experience to assess the efficacy of stereotactic radiosurgery (SRS) for dural carotid cavernous fistulas (DCCFs). We analyzed the clinical outcome, complications, and angiographic results.

METHODS

We performed a retrospective analysis of 18 consecutive patients with DCCFs treated by SRS alone using Gamma Knife between 2009 and 2015. Median target volume was 2.6 cm³ (range, 0.6-11.6 cm³), and median radiation dose to the target was 17 Gy (range, 14-19 Gy). Median follow-up period was 30 months (range, 6-65 months).

RESULTS

Fifteen patients (83%) achieved total obliteration of the DCCF, and a subtotal obliteration of the DCCF was achieved in 3 patients (17%). Total obliteration rates after SRS were 53% at 1 year and 90% at 2 years. Twelve patients (67%) showed complete recovery from symptoms or signs, and 6 patients (33%) showed incomplete recovery. Improvement rates of neurologic function after SRS were 56% at 1 month, 72% at 3 months, and 94% at 6 months. None of the patients experienced radiation-related complications. A univariate analysis revealed that absence of hypertension (P = 0.025), seizure (P = 0.025), and cortical venous drainage (P = 0.013) were significantly associated with symptoms improvement.

CONCLUSIONS

SRS for DCCFs offered a high obliteration rate with low risk of radiation-induced complications. In patients with benign DCCFs that are not amenable to embolization or microsurgery, SRS is a safe and effective treatment for complete obliteration of the arteriovenous shunt and for improving quality of life.

Quantifying the Cerebral Hemodynamics of Dural Arteriovenous Fistula in Transverse Sigmoid Sinus Complicated by Sinus Stenosis: A Retrospective Cohort Study

BACKGROUND AND PURPOSE

Sinus stenosis occasionally occurs in dural arteriovenous fistulas. Sinus stenosis impedes venous outflow and aggravates intracranial hypertension by reversing cortical venous drainage. This study aimed to analyze the likelihood of sinus stenosis and its impact on cerebral hemodynamics of various types of dural arteriovenous fistulas.

MATERIALS AND METHODS

Forty-three cases of dural arteriovenous fistula in the transverse-sigmoid sinus were reviewed and divided into 3 groups: Cognard type I, type IIa, and types with cortical venous drainage. Sinus stenosis and the double peak sign (occurrence of 2 peaks in the time-density curve of the ipsilateral drainage of the internal jugular vein) in dural arteriovenous fistula were evaluated. "TTP" was defined as the time at which a selected angiographic point reached maximum concentration. TTP of the vein of Labbé, TTP of the ipsilateral normal transverse sinus, trans-fistula time, and trans-stenotic time were compared across the 3 groups.

RESULTS

Thirty-six percent of type I, 100% of type IIa, and 84% of types with cortical venous drainage had sinus stenosis. All sinus stenosis cases demonstrated loss of the double peak sign that occurs in dural arteriovenous fistula. Trans-fistula time (2.09 seconds) and trans-stenotic time (0.67 seconds) in types with cortical venous drainage were the most prolonged, followed by those in type IIa and type I. TTP of the vein of Labbé was significantly shorter in types with cortical venous drainage. Six patients with types with cortical venous drainage underwent venoplasty and stent placement, and 4 were downgraded to type IIa.

CONCLUSIONS

Sinus stenosis indicated dysfunction of venous drainage and is more often encountered in dural arteriovenous fistula with more aggressive types. Venoplasty ameliorates cortical venous drainage in dural arteriovenous fistulas and serves as a bridge treatment to stereotactic radiosurgery in most cases.

Torcular dural arteriovenous fistula treated via stent placement and angioplasty in the affected straight and transverse sinuses: case report

The successful obliteration of torcular dural arteriovenous fistula (DAVF) with a diffuse shunt in the affected sinus may require complex treatment strategies. Therapeutic goals include the preservation of normal venous drainage and complete obliteration of shunt flow. The authors report the case of a torcular DAVF. The treatment of this type of AVF may require a combined approach with transarterial and transvenous embolization, open surgery, or radiosurgery and is associated with many problems. Stent placement and angioplasty in the affected sinus result in compression of the fistulous dural wall of the sinus and decrease shunt flow. In cases in which there is a diffuse shunt in the affected sinus and no evident shunt point, such as in AVFs involving venous pouches and parasinuses, sealing the fistula orifice with self-expandable stents and angioplasty (balloon inflation) is considered the best treatment option to preserve normal cerebral venous sinus drainage and obliterate shunt flow. In such cases, the authors recommend using one or more self-expandable and closed-cell stents and using angioplasty to avoid endoleakage into the gap between the stent graft and the vessel wall.

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.

[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.

Down but not out

A 20-year-old Hispanic man with Down syndrome presented with progressively worsening headache, fluctuating decreased vision, and bilateral optic disk edema. Magnetic resonance imaging of the head showed an empty sella, and magnetic resonance venography showed thrombosis of left transverse and sigmoid sinuses. Catheter angiography angiogram showed a dural arteriovenous fistula in the wall of left transverse and sigmoid sinuses. The patient underwent Onyx endovascular embolization of the fistula, resulting in its angiographic obliteration, followed by resolution of his clinical signs and symptoms.

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.

Intracranial dural arteriovenous fistulas: clinical characteristics and management based on location and hemodynamics

Objective

A dural arteriovenous fistula (DAVF) generally refers to a vascular malformation of the wall of a major venous sinus. These lesions have diverse symptoms according to the location and venous drainage, and require multidisciplinary treatment. We report on our experience and analyze the treatment outcome of intracranial DAVFs for a nine-year period.

Methods

Between January 2000 and December 2008, 95 patients with intracranial DAVFs were enrolled in this study. A retrospective review of clinical records and imaging studies of all patients was conducted. Endovascular embolization, surgical interruption, gamma knife stereotactic radiosurgery (GKS), or combinations of these treatments were performed based on clinical symptoms, lesion location, and venous drainage pattern.

Results

Borden type I, II, and III were 34, 48, and 13 patients, respectively. Aggressive presentation was reported in 6% of Borden type I, 31% of Borden type II, and 77% of Borden type III DAVFs, respectively, and DAVFs involving transverse, sigmoid, and superior sagittal sinus. Overall, the rate of complete obliteration was 68%. The complete occlusion rates with a combination treatment of endovascular embolization and surgery, surgery alone, and endovascular embolization were 89%, 86%, and 80%, respectively. When GKS was used with embolization, the obliteration rate was 83%, although it was only 54% in GKS alone. Spontaneous obliteration of the DAVF occurred in three patients. There were a few complications, including hemiparesis (in microsurgery), intracranial hemorrhage (in endovascular embolization), and facial palsy (in GKS).

Conclusion

The hemorrhagic risk of DAVFs is dependent on the location and hemodynamics of the lesions. Strategies for treatment of intracranial DAVFs should be decided according to the characteristic of the DAVFs, based on the location and drainage pattern. GKS can be used as an optional treatment for intracranial DAVFs.

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.

Endovascular treatment of tentorial dural arteriovenous fistulae

Tentorial dural arteriovenous fistula (DAVF) is a rare vascular disease, which accounts for less than 4% of all cases of intracranial DAVF. Because of the high risk of intracranial hemorrhage, patients with tentorial DAVF need aggressive treatment. Management approaches are still controversial, and endovascular treatment has emerged as an effective alternative. In the current work, we describe our experience with the endovascular approach in the treatment of these deep and complex DAVF of the tentorium. Eight patients were treated between January 2006 and July 2009. Six patients (75%) presented with intracranial hemorrhage related to the DAVF rupture. Four patients (50%) had subarachnoid bleeding and two had intraparenchymal hematoma. Endovascular treatment was performed via the transarterial route alone in five cases (62.5%), by the transvenous approach in two cases (25.0%) and in a combined procedure using both arterial and venous routes in one patient (12.5%). Complete obliteration of the fistula was achieved in all cases. The outcome at 15 months was favorable (modified Rankin scale 0-3) in seven (87.5%) patients. Complete cure of the lesion was confirmed in these cases. This paper reports on the effectiveness of endovascular treatment in tentorial DAVF management. The choice of the venous versus the arterial approach is determined by regarding different anatomical dispositions.

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.

Lumbar peritoneal shunt containing a programmable valve for intracranial hypertension caused by Borden type 1 dural arteriovenous fistulas

Three male patients underwent lumbar peritoneal (LP) shunt for intracranial hypertension caused by intracranial Borden type 1 dural arteriovenous fistulas (D-AVFs). Endovascular treatment was performed initially, but it was ineffective in all cases. Before LP shunt, the Mariotte blind spot expanded in all cases and severe papilledema was observed in two cases. We managed the opening pressure of the shunt system in accordance with patient symptoms. Mariotte blind spot expansion and papilledema disappeared after LP shunt. Follow-up cerebral angiography revealed spontaneous closure of D-AVFs in one case and aggressive conversion in two cases. D-AVFs were completely closed by transvenous embolization. Because the angioarchitecture of the fistula frequently worsens without deterioration of the symptom after LP shunt, follow-up angiography and additional treatment are important.

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.

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.

RECONSTRUCTIVE TREATMENT USING A STENT GRAFT FOR A DURAL ARTERIOVENOUS FISTULA OF THE TRANSVERSE SINUS IN THE CASE OF HYPOPLASIA OF THE CONTRALATERAL VENOUS SINUSES

OBJECTIVE

Transvenous coil embolization for transverse sinus (TS) and sigmoid sinus dural arteriovenous fistulae (DAVFs) is now recognized as one of the most effective treatment modalities. However, in the case of hypoplasia of the contralateral venous sinuses and internal jugular vein, complete occlusion of the ipsilateral sinus may cause fatal consequences. We describe a case of combined intravenous graft stent placement and transarterial coil embolization for DAVFs that involved the dominant right TS in a patient with hypoplasia of the contralateral venous sinuses.

CLINICAL PRESENTATION

A 50-year-old man presented with headache, left hand tremor, and pulsatile right tinnitus. A cerebral angiogram demonstrated a right TS DAVF that was supplied by tentorial branches of both internal carotid arteries, multiple branches of the right external carotid artery, and branches of the left occipital artery. Unfortunately, left TS and sigmoid sinus hypoplasia were observed.

INTERVENTION

A right TS balloon occlusion test revealed contrast stagnation of the cortical veins and of the right TS and superior sagittal sinus. In this case, the use of transvenous stent graft placement with or without transarterial embolization is safer and more effective than sacrifice of the right TS. We therefore performed balloon-expandable stent graft deployment at the right TS, and the remnant DAVF flow between the stent graft and venous sinus was treated with transarterial coil embolization. Postprocedural angiograms showed patent right TS outflow with disappearance of retrograde cortical venous drainage as well as complete eradication of the fistulous connections.

CONCLUSION

In a DAVF involving the dominant TS or sigmoid sinus in a patient with hypoplasia of the contralateral venous sinuses and an intolerable balloon occlusion test for the ipsilateral venous sinuses, the complete occlusion of the diseased venous sinus may cause hazardous consequences. In this situation, the use of a stent graft with or without transarterial embolization to preserve venous sinus flow can be an effective treatment.

The role of surgery for high-grade intracranial dural arteriovenous fistulas: importance of obliteration of venous outflow

Object

Surgical intervention may be required if endovascular embolization is insufficient to completely obliterate intracranial dural arteriovenous fistulas (DAVFs). The authors report their 14-year experience with 23 patients harboring diverse intracranial DAVFs that required surgical intervention.

Methods

Between 1993 and 2007, 23 patients underwent surgery for intracranial DAVFs. The following types of DAVFs were treated: superior petrosal sinus (in 10 patients); parietooccipital (in 3); confluence of sinuses and ethmoidal (in 2 each); and tentorial, falcine, occipital, transverse-sigmoid, superior sagittal, and cavernous sinuses (in 1 patient each). In all cases, the authors' goal was to obliterate the DAVF venous outflow by direct surgical interruption of the leptomeningeal venous drainage. Transarterial embolization was used primarily as an adjunct to decrease flow to the DAVF prior to definitive treatment.

Results

Complete angiographic obliteration of the DAVF was achieved in all cases. There were no complications of venous hypertension, venous infarction, or perioperative death. There were no recurrences and no further clinical events (new hemorrhages or focal neurological deficits) after a mean follow-up of 45 months.

Conclusions

The authors' experience emphasizes the importance of occluding venous outflow to obliterate intracranial DAVFs. Those that drain purely through leptomeningeal veins can be safely obliterated by surgically clipping the arterialized draining vein as it exits the dura. Radical excision of the fistula is not necessary.

Endovascular management of dural arteriovenous fistulas of the transverse and sigmoid sinus in 150 patients

INTRODUCTION

This study aimed to evaluate the safety and efficiency of the endovascular treatment of transverse-sigmoid sinus dural arteriovenous fistulas (TS_dAVF).

METHODS

A total of 150 consecutive patients and 348 procedures were evaluated.

RESULTS

Pulsatile tinnitus (81%), headache (15%), and intracranial hemorrhage (10%) were the most frequent manifestations of the TS_dAVFs. More than half of the affected sinuses were partially or completely thrombosed. Access-wise treatment was performed transarterial (n = 33), transvenous (n = 21), or a combination thereof (n = 96). A mean of 2.4 procedures per patient was required. Immediate postprocedural occlusion rate after transarterial embolization was 30% only. Transvenous treatment alone resulted in an early occlusion rate of 81%, with delayed complete obliteration of half of the remaining fistulas. After combined transarterial/transvenous treatment, the angiographic cure rate was 54%. At follow-up, 88% of patients with residual shunt after the treatment showed complete occlusion. The cumulative complication rate was 9% (n = 13), with minor adverse events in ten patients (7%) and major complications in three patients (2%).

CONCLUSION

Transvenous coil occlusion of the sinus segment with the adjacent dAVF site, eventually combined with transarterial occlusion of supplying arteries, is a very effective and well-tolerated treatment method. In selected patients, variations of these methods (e.g., sinus stenting, compartmental sinus occlusion) can be useful.

Treatment of dural arteriovenous fistula using ethylene vinyl alcohol (onyx) arterial embolization as the primary modality: short-term results

OBJECT

A dural arteriovenous fistula (DAVF) typically involves meningeal feeding arteries and can cause clinical symptoms ranging from tinnitus to rupture of draining cortical or parenchymal veins. Surgical treatment may be technically demanding. Ethylene vinyl alcohol (Onyx, ev3 Neurovascular) has several properties that make it potentially useful as a primary treatment agent for DAVF. Onyx is expected to be a permanent embolic agent. It should have a decreased risk of catheter retention when compared with other permanent embolic materials.

METHODS

The authors report a series of six patients with symptomatic DAVF who were treated initially with transarterial Onyx embolization and other endovascular techniques.

RESULTS

Five patients had complete occlusion of their DAVF noted on the follow-up angiogram obtained between 2 and 4 months. One patient had residual filling via a small arterial branch that was stable on follow-up angiography. None of the patients had worsening of neurological function. One case was complicated by a retained catheter fragment.

CONCLUSIONS

Transarterial Onyx embolization and other endovascular methods can angiographically obliterate DAVF. In some cases, embolization allowed occlusion of multiple arterial feeding arteries from a single arterial injection. Technically, the embolization was optimized when a microcatheter position immediately adjacent to the point(s) of fistulization was achieved.

Two consecutive dural arteriovenous fistulae in a child: a case report of successful treatment with gamma knife radiosurgery

INTRODUCTION

The occurrence of dural arteriovenous fistulae in children is quite rare. Endovascular embolization is typically the first line treatment. In general, Gamma Knife radiosurgery is used as adjuvant treatment and seldom performed as the first line treatment in children.

DISCUSSION

We report a case of a 27-month-old girl who presented with an initial dural arteriovenous fistula (AVF) located at anterior base of the left middle cranial fossa. She subsequently developed another dural AVF over the left transverse-sigmoid sinus region 2 years later.

CONCLUSION

Both fistulae were successfully obliterated with Gamma Knife radiosurgery.

Neurovascular radiosurgery

SUMMARY

This article focuses on the treatment of neurovascular diseases, in particular brain arteriovenous malformations (BAVMs), with radiosurgery. The target group for this review is physicians who manage patients with neurovascular diseases, but are not actively engaged in radiosurgery. Radiosurgery for BAVMs is an established treatment with clearly defined risks and benefits. The efficacy of radiosurgery for dural arteriovenous shunts (DAVSs) is probably similar but the treatment has not yet gained the same acceptance. Radiosurgical treatment of cavernomas (cavernous hemangiomas) remains controversial. Well founded predictive models for BAVM radiosurgery show: * The probability of obliteration depends on the dose of radiation given to the periphery of the BAVM. * The risk of adverse radiation effects depends on the total dose of radiation, i.e. the amount of energy imparted into the tissue. The risk is greater in centrally located lesions. The risk of damage to brainstem nucleii and cranial nerves must be added to the risk predicted from current outcome models. * The risk of hemorrhage during the time span before obliteration depends on the BAVM volume, the dose of radiation to the periphery of the lesion and the age of the patient. Central location is a probably also a risk factor.

Gamma Knife surgery for the management of intracranial dural arteriovenous fistulas

Object

The purpose of this study was to assess the efficacy and safety of Gamma Knife surgery (GKS) for the treatment of cavernous sinus dural arteriovenous fistulas (CSDAVFs) and other intracranial dural arteriovenous fistulas (ODAVFs).

Methods

Among the 238 GKS procedures performed for intracranial DAVFs in the authors' institute, 227 cases (146 CSDAVFs and 81 OIDAVFs) with clinical follow up formed the database from which the authors determined clinical outcome and the incidence of untoward events. One hundred ninety-five cases (118 CSDAVFs and 77 ODAVFs) with imaging follow up formed the database from which the authors determined the imaging results.

Older age, female sex, higher incidence of diabetes, and shorter duration of symptoms were noted more in cases of CSDAVF than in ODAVFs. Most patients had symptomatic improvement after GKS. A symptomatic cure was observed in one patient with CSDAVFs as early as 6 weeks. The cumulative cure rate based on follow-up angiography of CSDAVFs approached 75% at 24 months, which was much better than that of ODAVFs (approximately 50% at 24 months). A neuroimaging-based cure lagged behind that of the clinical symptoms. Overall, there were only two nonfatal intracerebral hemorrhages during the follow-up period, both occurring less than 1 week after GKS and both being Cognard Type IIa+b with initial aggressive symptoms. Transient deterioration of neurological status without hemorrhage was noted in six patients with ODAVFs. Thrombosis of the superior ophthalmic vein occurred in 11 patients with CSDAVFs, in two of whom there were unilateral visual impairments. There were three cranial nerve neuropathies: transient in one CSDAVF and one ODAVF involving the jugular foramen, and another one was a CSDAVF previously treated by conventional radiotherapy.

Conclusions

Gamma Knife surgery provides a safe and effective option for treatment of intracranial DAVFs with a low risk of complications. In cases of DAVFs with benign clinical presentation, GKS can serve as a primary treatment. In some cases of aggressive DAVFs in which there is extensive retrograde cortical vein drainage, combined treatment with embolization or surgery is suggested.

Gamma knife surgery for dural arteriovenous shunts: 25 years of experience

Object

The aim of this study was to assess the clinical efficacy of gamma knife surgery (GKS) in the treatment of dural arteriovenous shunts (DAVSs).

Methods

From a database of more than 1600 patients with intracranial arteriovenous shunts that had been treated with GKS, the authors retrospectively and prospectively identified 53 patients with 58 DAVSs from the period between 1978 and 2003. Four patients were lost to follow-up evaluation and were excluded from the series. Thus, this study is based on the remaining 49 patients with 52 DAVSs. Thirty-six of the shunts drained into the cortical venous system, either directly or indirectly, and 22 of these were associated with intracranial hemorrhage on patient presentation. The mean prescription radiation dose was 22 Gy (range 10–28 Gy).

All patients underwent a clinical follow-up examination. In 41 cases of DAVS a follow-up angiography study was performed. At the 2-year follow-up visit, 28 cases (68%) had angiographically proven obliteration of the shunt and in another 10 cases (24%) there was significant flow regression. Three shunts remained unchanged.

There was one immediate minor complication related to the administration of radiation. Furthermore, one patient had a radiation-induced complication 10 years after treatment, although she recovered completely. There was one posterior fossa bleed 2 months after radiosurgery; a hematoma, as well as a lesion, was evacuated, and the patient recovered uneventfully. A second patient had an asymptomatic occipital hemorrhage approximately 6 months postradiosurgery.

The clinical outcome after GKS was significantly better than that in patients with naturally progressing shunts (p < 0.01, chi-square test); figures on the latter have been reported previously.

Conclusions

Gamma knife surgery is an effective treatment for DAVSs, with a low risk of complications. Major disadvantages of this therapy include the time elapsed before obliteration and the possibility that not all shunts will be obliterated. Cortical venous drainage from a DAVS, a risk factor for intracranial hemorrhage, is therefore a relative contraindication. Consequently, GKS can be used in the treatment of both benign DAVSs with subjectively intolerable bruit and aggressive DAVSs not responsive to endovascular treatment or surgery.

Radiosurgery for dural arteriovenous fistulas

OBJECTIVE

Dural arteriovenous fistulas (DAVFs) comprise 10% to 15% of all arteriovenous malformations. Recent studies have demonstrated promising results when radiosurgery is used for DAVFs. We retrospectively analyzed our patients with DAVFs who received stereotactic radiosurgery with or without embolization.

METHODS

Between 1991 and 2002, 18 patients with 23 angiographically confirmed symptomatic DAVFs underwent gamma knife radiosurgery, either alone (n = 8) or in combination with embolization (n = 10). A retrospective chart review was performed to identify DAVF location, venous drainage pattern, radiosurgery dosimetry, clinical outcomes, and imaging results. The series included 9 men and 9 women with a mean age of 65 (range 50-89) years. Nine patients received particulate, coil, and/or absolute ethanol embolization before radiosurgery, and 1 patient received particulate embolization after radiosurgery. The mean duration of clinical follow-up was 43 (range 2-116) months. The mean margin radiosurgery dose was 20 (range 15-30) Gy.

RESULTS

Nine patients had complete resolution of their presenting symptoms, and 9 patients had resolution of all but 1 of their presenting symptoms. Angiographic follow-up (mean 46 months) was performed on 8 patients demonstrating complete obliteration in all the cases. Seven patients evaluated by magnetic resonance angiography or computed tomography angiography showed no evidence of DAVF (4 patients) or decreased DAVF size (3 patients). After radiosurgery, 1 patient developed a temporary hemiparesis. Two permanent neurological deficits occurred after embolization before radiosurgery. No patient had an intracranial hemorrhage after treatment.

CONCLUSION

Stereotactic radiosurgery provides effective long-term relief of symptoms in selected patients with DAVFs.