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

A Rare Case of Right Trigeminal Neuralgia Due to Dural Arteriovenous Fistula

Trigeminal neuralgia (TGN) is often caused by a neurovascular conflict at the root entry zone of the fifth nerve. Dural arteriovenous fistula (DAVF) accounts for 3%–4% cases of TGN. We report a posttraumatic head injury patient, presenting with gait ataxia and right facial pain. Radiographic evidence with magnetic resonance imaging and digital subtraction angiography was suggestive of DAVF. Surgical clipping and obliteration of fistula alleviated the TGN.

Role of Surgical Intervention for Intracranial Dural Arteriovenous Fistulas With Cortical Venous Drainage in an Endovascular Era: A Case Series

BACKGROUND

Intracranial dural arteriovenous fistulae (dAVFs) with cortical venous drainage (CVD) require treatment because of their aggressive clinical presentation and natural history. Although endovascular treatment is effective for the majority of these lesions in the current endovascular era, surgical management has been required if the lesions are not amenable to or fail endovascular treatments.

OBJECTIVE

To demonstrate the angioarchitecture that may necessitate surgical intervention.

METHODS

A retrospective review of the patients with intracranial dAVFs with CVD treated at 2 academic institutions between January 1, 2009, and July 31, 2019 was performed. Patients who required surgical intervention were selected in this study, and angiographic findings were analyzed.

RESULTS

A total of 81 dAVFs in 80 patients were treated during the study period. Endovascular treatments were attempted for 72 (88.9%) dAVFs, resulting in complete obliteration in 55 (76.4%). Surgical interventions were performed in 18 (22.2%) dAVFs, resulting in complete obliteration in all lesions. Overall, complete obliteration was achieved in 74 (93.7%) of 79 dAVFs with follow-up. In the surgically treated dAVFs, curative transarterial embolization was deterred by the angioarchitecture, which included dominant feeding vessels from the ophthalmic artery, meningohypophyseal trunk, posterior meningeal artery, pial artery, or ascending pharyngeal artery. Drainage through tortuous cortical vein, deep venous system, or isolated sinus made transvenous approach challenging.

CONCLUSION

Despite continued improvement in endovascular technology, surgical approaches to dAVFs are still of great value as initial and salvage treatment of dAVFs with angioarchitecture hampering endovascular treatment.

Mixed Pial-Dural Arteriovenous Malformation in the Anterior Cranial Fossa Mimicking Dural Arteriovenous Fistula

Mixed pial-dural arteriovenous malformation (MpdAVM) and dural arteriovenous fistula (dAVF) are rare entities in the anterior cranial fossa (ACF). As dural-pial vascular anastomosis can exist near the cribriform plate, MpdAVM with a small nidus, which cannot be apparently identified, can be logically indistinguishable from dAVF in ACF. A 71-year-old man was referred for evaluation of possible intracranial vascular malformation. Cerebral angiography revealed an arteriovenous shunt in the ACF. The lesion was fed by the bilateral ethmoidal arteries and right orbitofrontal artery, draining through the bilateral cortical veins to the superior sagittal sinus. As a nidus was not detected, dAVF was suspected. Venous interruption was planned with direct surgery. Intraoperatively, an arterial aggregation was observed in the right frontal lobe. The arterial aggregation seemed to be connected to the interrupted drainer in the right ACF. The arterial aggregation was removed and pathologically diagnosed as arteriovenous malformation. Postoperatively, intracerebral hemorrhage was confirmed, and postoperative cerebral angiography confirmed the resolved arteriovenous shunt. The intracranial hemorrhage was possibly due to the timing gap between drainer interruption and removal of the nidus. MpdAVM with a small nidus in the ACF can mimic dAVF. Clinicians must be aware that an unremoved nidus of MpdAVM may postoperatively result in fatal intracranial hemorrhage.

Intracranial Dural Arteriovenous Fistulas: The Sinus and Non-Sinus Concept

INTRODUCTION

Dural arteriovenous fistulas (dAVFs) account for 10-15% of all intracranial arteriovenous lesions. Different classification strategies have been proposed in the course of the years. None of them seems to guide the treatment strategy.

OBJECTIVE

We expose the experience of the vascular group at Niguarda Hospital and we propose a very practical classification method based on the location of the shunt. We divide dAVF in sinus and non-sinus in order to simplify our daily practice, as this classification method is simply based on the involvement of the sinuses.

MATERIAL AND METHODS

477 intracranial dural arteriovenous fistulas have been treated. 376 underwent endovascular treatment and 101 underwent surgical treatment. Cavernous sinus DAVFs and Galen ampulla malformations have been excluded from this series as they represent a different pathology per se. 376 dAVFs treated by endovascular approach: 180 were sinus and 179 were non-sinus. 101 dAVFs treated with surgical approach: 15 were sinus and 86 were non-sinus.

DISCUSSION

Of the 477 intracranial dAVF the recorded mortality and severe disability was 3% and morbidity less than 4%. All patients underwent a postoperative DSA with nearly 100% of complete occlusion of the fistula. At a mean follow-up of 5 years in one case there was a non-sinus fistula recurrence, due to the presence of a partial clipping of "piè" of the vein.

CONCLUSIONS

The sinus and non-sinus concept has guided our institution for years and has led to good clinical results. This paper intends to share this practical classification with the neurosurgical community.

Cognard Grade IV Tentorial Dural Arteriovenous Fistula Presenting as Trigeminal Neuralgia: Endovascular Management

Tentorial dural arteriovenous fistulas have an increased risk of rupture and hemorrhage, and therefore require urgent treatment to occlude the fistula and proximal venous drainage. This is usually accomplished via endovascular treatment. We present a case of a Cognard grade IV dural arteriovenous fistula that presented as trigeminal neuralgia. This video showcases the angiographic vascular composition of the lesion with main feeders coming from the middle meningeal artery and the tentorial artery of Bernasconi and Cassinari. Details, benefits, and risks of the procedure were thoroughly discussed with the patient and consent was obtained prior to the procedure. We performed endovascular Onyx embolization through a distal branch of the right middle meningeal artery. We were able to successfully occlude the lesion using Onyx embolization and the patient had significant improvement of her pretreatment trigeminal neuralgia.

Complication rate, cure rate, and long-term outcomes of microsurgery for intracranial dural arteriovenous fistulae: a multicenter series and systematic review

Although microsurgery is an established treatment modality for intracranial dural arteriovenous fistula (dAVF), data regarding the perioperative complication rate, cure rate, and long-term outcomes remain scarce. The aims of this study were to describe our original experience with microsurgery, including the surgical complications and pitfalls, and conduct a systematic review of the relevant literature. A multicenter cohort of patients with dAVF treated by microsurgery was retrospectively assessed. In addition, the PubMed database was searched for published studies involving microsurgery for dAVF, and the complication rate, cure rate, and long-term outcomes were estimated. The total number of patients in our multicenter series and published articles was 553 (593 surgeries). The overall rates of transient complications, permanent complications, death, and incomplete treatment were 11.4, 4.0, 1.2, and 6.5%, respectively. A favorable outcome was achieved for 90.1% patients, even though almost half of the patients presented with intracranial hemorrhage. Of note, the incidence of recurrence was only one per 8241 patient-months of postoperative follow-up. Surgeries for anterior cranial fossa dAVF were associated with a lower complication rate, whereas those for tentorial dAVF were associated with higher complication and incomplete treatment rates. The complication and incomplete treatment rates were lower with simple disconnection of cortical venous drainage than with radical occlusion/resection of dural shunts. Our findings suggest that the cure rate, complication rates, and outcomes of microsurgery for dAVF are acceptable; thus, it could be a feasible second-line treatment option for dAVF. However, surgeons should be aware of the specific adverse events of microsurgery.

Cranial dural arteriovenous shunts: selection of the ideal lesion for surgical occlusion according to the classification system

BACKGROUND

The types of cranial dural arteriovenous fistulae (cDAVFs) that constitute good surgical candidates are unclear despite the use of classifications. We aimed to compare the DES classification with other classification schemes in identifying "ideal lesions for surgery." The DES scheme is based on two features: the level of the shunt (BVS, bridging vein shunt; DSS, dural sinus shunt; ISS, isolated sinus shunt; EVS, emissary vein shunt) and the type of leptomeningeal venous reflux (LVR) (direct, exclusive, strained).

METHODS

In this observational cohort study, the angiographies of 20 consecutive patients treated over 1 year were analyzed retrospectively. We defined cDAVFs as ideal for surgery, if cure may be achieved by disconnecting the arterialized draining vein through a single craniotomy. To evaluate the performance of each classification scheme in identifying the "ideal lesion for surgery," we carried out a sensitivity analysis of the Borden, Cognard, and DES schemes.

RESULTS

Eight lesions were Borden type 3 and 1 type 2, and 11 type 1. According to Cognard, 2 lesions were type IV, 2 type III, 1 type IIa+b, 11 type I, and 4 lesions could not be clearly classified. According to the DES scheme, 8 lesions were DSS, 4 BVS, 3 ISS, and 5 EVS. All 4 lesions classified as BVS in the DES were ideal lesions for surgery (sensitivity, specificity, PPV, NPV 100%). Not all high-grade lesions according to Borden were good surgical candidates.

CONCLUSION

The DES scheme, as opposed to other classifications, facilitates the therapeutic decision-making especially for selecting candidates for surgery.

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.

Surgical management of superior petrosal sinus dural arteriovenous fistulae with dominant internal carotid artery supply

Background While technological advances have improved the efficacy of endovascular techniques for tentorial dural arteriovenous fistulae (DAVF), superior petrosal sinus (SPS) DAVF with dominant internal carotid artery (ICA) supply frequently require surgical intervention to achieve a definitive cure. Methods To compare the angiographic and clinical outcomes of endovascular and surgical interventions in patients with SPS DAVF, the records of all patients with tentorial DAVF from August 2010 to November 2015 were reviewed. Results Within this cohort, eight patients with nine SPS DAVF were eligible for evaluation. Five DAVF were initially treated with endovascular embolization, while four underwent surgical occlusion without embolization. Of the SPS DAVF treated with embolization, two (40%) remained occluded on follow-up, while the remaining three (60%) persisted/recurred and required surgical intervention for definitive closure. Of the four SPS DAVF treated with primary surgical occlusion, all four (100%) remained closed on follow-up. In addition, of the three SPS DAVF that persisted/recurred following embolization and required subsequent surgical closure, all three (100%) remained occluded on follow-up. Two (100%) SPS DAVF that were successfully treated with embolization had major or minor external carotid artery supply, while the three (100%) persistent lesions had major ICA supply via the meningohypophyseal trunk (MHT). Three (75%) of the four SPS DAVF treated with primary surgical occlusion had dominant MHT supply. Conclusion Complete endovascular closure of SPS DAVF with dominant ICA supply via the MHT may be difficult to achieve, while upfront surgical intervention is associated with a high rate of complete occlusion.

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

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

Endovascular management of intracranial dural arteriovenous fistulas

Dural arteriovenous fistulas are a heterogeneous group of lesions that comprise 10-15% of intracranial vascular malformations. The treatment strategy is devised after careful consideration of the arterial supply, venous drainage, clinical presentation, and risk of progression, hemorrhage, or neurologic decline. With recent advancements in endovascular technology, the majority of dural arteriovenous fistulas can be treated with either transarterial or transvenous embolization. Those that cannot be fully treated by endovascular means are approached with either adjuvant surgery or radiotherapy.

Onyx removal after embolization of a superior sagittal sinus dural arteriovenous fistula involving scalp artery

BACKGROUND

Most dural arteriovenous fistula (DAVF) in superior sagittal sinus (SSS) requires multimodal treatment. Onyx embolization is useful for DAVF; however, scalp artery embolization has cast extrusion risk.

CASE DESCRIPTION

A 59-year-old male presented with involuntary movements of both legs and progressive dementia. Cerebral angiography demonstrated the DAVF in the SSS fed by bilateral superficial temporal, occipital, and middle meningeal arteries. The posterior SSS was thrombosed, and the main drainers were cortical veins. Combined treatment with transarterial embolization using Onyx and transvenous embolization using coils was performed. Although symptoms were improved, a small DAVF remained. Two months later, Onyx cast extrusion through the scalp was observed, requiring removal and debridement because of infection at the extrusion sites. Surgery for the residual DAVF would be difficult because of scalp condition; therefore, an additional endovascular treatment was conducted, completely occluding DAVF.

CONCLUSION

Onyx embolization is useful for DAVF; however, scalp artery embolization has cast extrusion risk. Therefore, scalp infection should be considered because it may preclude additional surgical procedures.

Visual Field Defect after Transfrontal Sinus Approach of Ethmoidal Dural Arteriovenous Fistulas (eDAVFs) : Experience and Complication of Transfrontal Sinus Approach

The approach to ethmoidal dural arteriovenous fistulas (eDAVFs) is usually via a pterional or a frontal craniotomy. However, the transfrontal sinus is a more direct route to the fistula. The aim of this report is to describe our experience and associated complications occurring as a result of flow diversion in the transfrontal sinus approach for eDAVFs. In this report, we discuss visual field defects occurring after a transfrontal sinus operation. This approach is most direct for surgical treatment of an eDAVF, enabling preservation of neural structures with minimal to no negative effects on the brain. Although the surgery was uneventful, the patient presented with a left side visual field defect. An ophthalmologic exam detected an arterial filling delay in the choroidal membrane and ischemic optic neuropathy was highly suspected. The patient is currently recovering under close observation with no special treatment. The transfrontal sinus approach provides the most direct and shortest route for eDAVFs, while minimizing intraoperative bleeding. However, complications, such as visual field defects may result from a sudden flow diversion or eyeball compression due to scalp traction.

Outcome after intracranial haemorrhage from dural arteriovenous fistulae; a systematic review and case-series

Dural arteriovenous fistulae (DAVFs) are a rare cause of intracranial haemorrhage. We aimed to investigate outcome of patients with intracranial haemorrhage from a DAVF. We performed a systematic literature search for studies reporting outcome after intracranial haemorrhage caused by a DAVF. We used predefined selection criteria and assessed the quality of the studies. In addition, we studied outcome in all patients with DAVF who had presented with intracranial haemorrhage at two university centers in the Netherlands, between January 2007 and April 2012. We calculated case fatality and proportions of patients with poor outcome (defined as modified Rankin Scale ≥ 3 or Glasgow Outcome Scale ≤ 3) during follow-up. We investigated mean age, sex, mid-year of study and percentage of patients with parenchymal haemorrhage as determinants of case fatality and poor outcome. The literature search yielded 16 studies, all but two retrospective and all hospital-based. Combined with our cohort of 29 patients the total number of patients with DAVF-related intracranial haemorrhage was 326 (58 % intracerebral haemorrhage). At a median follow-up of 12 months case fatality was 4.7 % (95 % CI 2.5–7.5; 17 cohorts) and the proportion of patients with poor outcome 8.3 % (95 % CI 3.1–15.7; nine cohorts). We found no effect of mean age, sex, mid-year of the cohorts and percentage of patients with parenchymal haemorrhage on either outcome. Hospital based case-series suggest a relatively low risk of death and poor outcome in patients with intracranial haemorrhage due to rupture of a DAVF. These risks may be underestimated because of bias.

Interhemispheric approach for endoscopic ligation of an anterior cranial fossa dural arteriovenous fistula

We describe the endoscopic ligation of an anterior cranial fossa (ACF) dural arteriovenous fistula (DAVF) through an interhemispheric approach. Intracranial DAVF of the ACF are rare and associated with an aggressive natural history, due to their ubiquitous direct cortical venous drainage and frequent coincidence of venous ectasia. Although surgical ligation is the preferred treatment for ACF DAVF, the role of endoscopy in the surgical management of DAVF is undefined. A 53-year-old woman was incidentally diagnosed with an ACF DAVF. Cerebral angiography showed a Borden type III, Cognard type IV left sided ACF DAVF, supplied by ethmoidal branches of the bilateral ophthalmic arteries and draining directly into an enlarged and ectatic left inferior frontal cortical vein, with a venous varix distal to the point of fistulization. An initial attempt at endovascular treatment from a transvenous approach was unsuccessful, due to significant stenosis of the left cavernous sinus. Therefore, we elected to proceed with surgical ligation. From an interhemispheric approach and under the guidance of frameless stereotactic neuronavigation, a 0° endoscope was advanced into the interhemispheric fissure until the arterialized draining vein was visualized. After dissecting along the draining vein to the point of fistulization, the proximal portion of the draining vein was ligated. Intraoperative angiography confirmed complete obliteration of the DAVF, and the patient was asymptomatic at the 6 week postoperative follow-up. Endoscopy provides excellent visualization of ACF DAVF and can safely facilitate surgical treatment in appropriately selected patients with these lesions.

Transfrontal sinus approach for an anterior cranial fossa, ethmoidal, dural arteriovenous fistula

Background:

Ethmoidal dural arteriovenous fistulas (eDAVFs) are usually approached via a pterional or a frontal craniotomy. A more direct route to the fistula is possible through a purely transfrontal sinus approach. The aim of this report is to illustrate the interest of transsinus frontal approach for eDAVFs.

Case Description:

The transfrontal sinus approach is described and illustrated in a case of an ethmoidal arteriovenous fistula. This approach is the most direct when treating an eDAVF surgically, allowing preserving neural structures with minimal to no brain manipulation.

Conclusion:

For eDAVFs, the purely transfrontal sinus approach is highly worth considering in cases of large frontal sinuses.

Advances in Radiosurgery for Arteriovenous Malformations of the Brain

Arteriovenous malformations of the brain are a considerable source of morbidity and mortality for patients who harbor them. Although our understanding of this disease has improved, it remains in evolution. Advances in our ability to treat these malformations and the modes by which we address them have also improved substantially. However, the variety of patient clinical and disease scenarios often leads us into challenging and complex management algorithms as we balance the risks of treatment against the natural history of the disease. The goal of this article is to provide a focused review of the natural history of cerebral arteriovenous malformations, to examine the role of stereotactic radiosurgery, to discuss the role of endovascular therapy as it relates to stereotactic radiosurgery, and to look toward future advances.

Directional Intraoperative Doppler Ultrasonography During Surgery on Cranial Dural Arteriovenous Fistulas

BACKGROUND:

Directional intraoperative Doppler (dioDoppler) ultrasonography is well established as a tool in the surgery of intracranial aneurysms and cerebral arteriovenous malformations. The literature provides little information about the possible usefulness of this method during surgery on cranial dural arteriovenous fistulas (dAVFs).

OBJECTIVE:

To present our experience with the use of dioDoppler during surgery on cranial dAVFs.

METHODS:

All patients undergoing craniotomy for cranial dAVF from January 2007 to October 2012 in which dioDoppler was used were included in the study. We reviewed patient records, operating protocols, radiological images, dioDoppler files, and intraoperative videos.

RESULTS:

During the study period, 12 patients with cranial dAVFs underwent surgical treatment facilitated by dioDoppler. Four patients were operated on acutely for cerebral bleeds, and 8 patients were treated for various cerebral symptoms and the assumption of a significant risk for intracranial bleed. Three advantages of dioDoppler were unequivocal identification of veins with cortical/deep venous reflux from the fistula, verification of completeness of occlusion of the fistula, and identification of dural arterial feeders not visualized under the microscope.

CONCLUSION:

Reviewing our experience, we found that dioDoppler sonography is an easy, safe, effective, reliable, and instantaneous tool during surgery on cranial dAVFs.

Endovascular management of intracranial dural arteriovenous fistulas: a review

Dural arteriovenous fistulas (DAVFs) are rare pathological entities presenting with a diverse clinical course, ranging from benign to life-threatening. Digital subtraction angiography remains the gold standard in the diagnosis of clinically suspected DAVFs. This article reviews the ethiopathogenesis, natural history, classification systems, clinical and angiographic features, and the current treatment strategies for these complex lesions. The management of DAVFs may include conservative treatment, endovascular intervention, microsurgery, and stereotactic radiosurgery. A multidisciplinary approach involving a neurosurgeon, interventional neuroradiologist, and neurologist is required before considering any type of treatment modality. The indication for the best therapeutic alternative must be individualized for each patient.

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.

Spontaneous closure of intracranial dural arteriovenous fistulas: a report of 3 cases

Spontaneous closures of dural arteriovenous fistulas (dAVFs) are rare. We present spontaneous occlusion of dAVFs in 3 cases (one type IIa dAVF, one type IIb and one type III). Patients were 3 males with a mean age of 55 years (range 45-61). For two patients, the dAVF was revealed by hemorrhage. No head trauma was recorded at the interrogatory. Mean delay for spontaneous closure was 4 months (3-5 months). Review of the literature about this rare occurrence is presented and the factors that may lead to spontaneous occlusion of dAVFs are discussed.

Single stage transcranial exposure of large dural venous sinuses for surgically-assisted direct transvenous embolization of high-grade dural arteriovenous fistulas: technical note

BACKGROUND

High-grade dural arteriovenous fistulas (DAVFs) with retrograde cortical leptomeningeal drainage are formidable lesions because of their risk for intracranial hemorrhage. Treatment is aimed at occluding venous outflow to achieve obliteration of the fistula. In DAVFs that involve a large dural venous sinus (transverse sigmoid sinus or superior sagittal sinus), occluding venous outflow can be accomplished endovascularly with transvenous embolization. However, in some cases of DAVFs with reflux into cortical leptomeningeal veins, there may be venous restrictive disease downstream, such as occlusive thrombosis, which can prohibit endovascular access via the transfemoral or transjugular routes. In these instances, a transcranial approach can be performed to expose the large dural venous sinus distal to the site of occlusion for direct catheterization of the venous outflow for transvenous embolization. This combined surgical and endovascular strategy provides direct access to the venous outflow and bypasses the site of thrombotic obstruction.

METHODS

In this report, we describe our technique of single stage surgically-assisted transvenous embolization in three patients with high-grade DAVFs involving a large dural sinus.

RESULTS

All patients achieved complete obliteration of their DAVFs without any venous related complications.

CONCLUSION

Our technique of surgically-assisted direct transvenous embolization of high-grade DAVFs can be successfully performed as a single stage in the operating room with intraoperative angiography and stereotactic image guidance.

The Natural History of Cerebral Dural Arteriovenous Fistulae

BACKGROUND:

Hemorrhage from cerebral dural arteriovenous fistulae (dAVF) is a considerable source of neurological morbidity and even mortality.

OBJECTIVE:

To evaluate the natural history of cerebral dAVF.

METHODS:

We reviewed our own cohort of 70 dAVF and incorporated results from the literature, synthesizing pooled hemorrhage rates and evaluating risk factors for 395 dAVF in 6 studies.

RESULTS:

No hemorrhages occurred during 409 lesion-years of follow-up of Borden type I dAVF; however, cortical venous drainage developed in 1.4%. Like type I dAVF, type II dAVF demonstrated a female predilection and were most commonly transverse-sigmoid or cavernous. Eighteen percent of type II dAVF presented with hemorrhage (95% confidence interval [CI]: 8%-36%), and the annual hemorrhage rate was 6% (95% CI: 0.1%-19%). Borden type III dAVF demonstrated a male predilection and were most commonly tentorial or petrosal. Thirty-four percent presented with hemorrhage (95% CI: 0.4%-49%), with an annual hemorrhage rate of 10% (95% CI: 4%-20%), increasing to 21% for those with venous ectasia (95% CI: 4%-66%). The hemorrhage rate decreased to 2% for asymptomatic or minimally symptomatic type II or III dAVF (95% CI: 0.2%-8%), and increased to 10% for those presenting with nonhemorrhagic neurological deficits (95% CI: 0.9%-41%) and to 46% for those presenting with hemorrhage (95% CI: 11%-130%).

CONCLUSION:

Venous ectasia is a significant risk factor for hemorrhage among dAVF with cortical venous drainage. In addition, those with hemorrhagic presentation, even compared with nonhemorrhagic neurological deficit presentation, as well as Borden type III dAVF compared with type II dAVF demonstrated a trend toward greater hemorrhage rates.

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.

Mixed pial-dural arteriovenous malformation in the anterior cranial fossa--two case reports

Most arteriovenous malformations (AVMs) associated with the meningeal artery in the anterior cranial fossa are the pure dural type, and mixed pial-dural AVMs are rare. Two types of mixed pial-dural AVM occur in the anterior cranial fossa according to the shunting point: one with the nidus in the brain parenchyma of the frontal lobe, and the other with the shunting point in the dura mater. We describe two patients with AVMs fed by the anterior ethmoidal arteries and the persistent primitive olfactory artery, with the nidus located in the pure brain parenchyma of the inferior aspect of frontal lobe, and drained via an abnormal cortical vein into the cavernous and superior sagittal sinuses. The importance of occluding the venous outflow to obliterate intracranial dural arteriovenous fistula (AVF) is emphasized. However, removal of the nidus in the brain parenchyma is required. The presence of a pial feeder should be considered before diagnosis of dural AVF of the anterior cranial fossa, and preoperative detailed evaluation for the pial supply and shunting point is mandatory.

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.

Intraoperative angiography for cranial dural arteriovenous fistula

BACKGROUND AND PURPOSE

IA is a valuable adjunct during surgery for a variety of neurovascular diseases; however, there are no reported series describing IA for DAVFs. This study was undertaken to evaluate the safety and efficacy of IA for DAVFs.

MATERIALS AND METHODS

A retrospective review of DAVF surgical cases during a 20-year period was conducted, and cases with IA were evaluated. Clinical details, surgical and angiographic findings, and postoperative outcomes were reviewed. The incidence of residual fistula on IAs, the utility of the surgical procedure, and the incidence of false-negative findings on IA were also determined.

RESULTS

IA was performed in 29 patients (31 DAVFs) for DAVFs. The distribution of the fistulas was the following: transverse-sigmoid (n = 9), tentorial (n = 6), torcular (n = 3), cavernous sinus (n = 4), SSS (n = 4), foramen magnum (n = 3), and temporal-middle fossa (n = 2). Twelve patients had undergone prior embolization, while 6 patients had unsuccessful embolization procedures. Thirty-eight surgeries were performed for DAVF in 29 patients, and IA was performed in 34 surgeries. Forty-four angiographic procedures were performed in the 34 surgeries. Nine patients underwent multiple angiographies. In 11 patients (37.9%), IA revealed residual fistula after the surgeon determined that no lesion remained. This led to further exploration at the same sitting in 10 patients, while in 1 patient, further surgery was performed at a later date. False-negative findings on IA occurred in 3 patients (10.7%).

CONCLUSIONS

IA is an important adjunct in surgery for DAVF. In this series, it resulted in further surgical treatment in 37.9% of patients. However, there was a 10% false-negative rate, which justified subsequent postoperative angiography.

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.

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.

[A case of dural arteriovenous fistula associated with bilateral thalamic lesions]

We report a 51-year-old man with a dural arteriovenous fistula (DAVF) associated with bilateral thalamic lesions. He was admitted to our hospital because of cognitive disorder. T2-weighted MRI and fluid-attenuated inversion recovery (FLAIR) sequence of the brain revealed symmetric hyperintense lesions of bilateral thalamus and abnormal flow void that represents the enlarged veins. Cerebral angiography demonstrated DAVF in the superior petrosal sinus (SPS). It was mainly supplied by the internal carotid arteries. The strait sinus was not revealed, and the venous drainage was retrograde into the internal cerebral vein. Therefore the mechanism of cognitive disorder in this case was considered to be vasogenic edema of the bilateral thalamus due to DAVF of SPS. We decided to treat the DAVF by embolization via the feeding arteries approach, because strait sinus was not revealed and venous approach was difficult. After embolization, the size of DAVF was remarkably reduced. His cognitive disorder was markedly improved and the hyperintense area on T2-weighted MRI and FLAIR sequence had disappeared. Cognitive disorder due to DAVF of SPS is very rare. It is also difficult to diagnose bilateral thalamic lesions as DAVF, but it may be reversible by DAVF treatment. Thus, early diagnosis and treatment is important. Like this case, abnormal flow void that represents the enlarged veins could help to diagnose bilateral thalamic lesions due to DAVF.