Treatment of dural arteriovenous malformations and fistulas

Dural arteriovenous fistulas (DAVFs) or malformations consist of pathological vascular channels located within the substance of the dura mater and usually involve the walls of a dural sinus or adjacent cortical vein. DAVFs can affect a variety of cerebral venous structures and can present at various clinical stages. Although some fistulas can spontaneously thrombose, the clinical course usually involves progression from venous sinus pressurization to occlusion and retrograde cortical venous drainage. The spectrum of clinical presentation ranges from an irritating pulse-synchronous bruit to a disabling neurologic ischemic deficit or life-threatening intracranial hemorrhage from venous hypertension. The authors present their clinical experience in the radiographic diagnosis and endovascular treatment of these potentially dangerous lesions.     

Treatment and outcome of spinal dural arteriovenous fistulas

Spinal dural arteriovenous fistula (dAVFs) are rare and often misdiagnosed entities. The choice between surgical treatment and embolization remains a matter of debate. We report on the cases of 18 patients (16 men, 2 women) with dAVF, who were treated surgically over an 11-year period. Patient age ranged from 32 to 84 years (mean 60 years). Six patients underwent embolization preoperatively. In three cases, angiography examinations failed to show feeding arteries on first examination at neuroradiological centers. Feeding arteries were at a different level than the fistula point in seven patients, two of them presenting with new anastomoses after embolization. Location of the fistula was midthoracic to lumbar. Seven patients were variously misdiagnosed with tumor, polyneuropathy, Guillain-Barré syndrome, syringomyelia, and knee disease. Clinical history was characterized by slowly progressive and fluctuating deterioration. Initial symptoms were mainly sensory loss and motor weakness, lasting for between 4 and 45 months before diagnosis (mean 15 months). Recurrent fistula after operation was found in one patient. In another patient, control angiography revealed a fistula at another level, and in a third, a fistula on the contralateral side. All three patients underwent reoperation. Temporary clinical deterioration was found in four patients, seven remained unchanged, and seven improved postoperatively. An attempt at embolization should be made following diagnostic angiography. Otherwise, surgery is our recommended treatment for spinal dural fistulas, as it has a lower failure rate. Because of the progressive natural course with severe deficits, we favor an early definitive treatment.     

Tentorial dural arteriovenous fistulas

BACKGROUND: Tentorial dural arteriovenous fistula is uncommon but is a life-threatening lesion. We present our experience with 5 patients with TDAVFs, review the relevant literature, and present the rationale of our current management strategy. METHOD: The data of 5 patients with TDAVFs treated in Huashan Hospital, Shanghai, China, between June 2002 and May 2003 were reviewed retrospectively, including their illness history, neuroimaging, operation records, and follow-up data. RESULTS: There were 3 females and 2 males with ages from 25 to 52 years (average, 38 years). Clinical manifestations were acute SAH in 2 patients and progressive neurologic deficits in 3 patients. Magnetic resonance imaging and DSA were major diagnostic and follow-up modalities. All cases belonged to Borden classification type 3. A tentorial marginal type was present in 3 cases, a tentorial lateral type in 1 case, and a tentorial medial type in 1 case. Preoperative transarterial embolization was done in 3 patients. All patients underwent craniotomy with the coagulation of the fistulas and surrounding tentorial dura mater, and the disconnection of leptomeningeal venous drainage. The surgical approaches were via transanterior petrous approach in 3 cases, subtemporal intradural approach in 1 case, and unilateral occipital and transtentorial approach in 1 case. All patients had clinical improvement. There was no surgical mortality and morbidity. Postoperative DSA confirmed obliteration of TDAVFs in 3 cases; MRI demonstrated the thrombosis of venous aneurysm and disappearance of previous brainstem edema in 1 case, and partial thrombosis of venous aneurysm in another case. Follow-up study ranging from 2 to 3 years (average, 2.5 years) showed no recurrence, and all patients have resumed their normal activities. CONCLUSIONS: Tentorial dural arteriovenous fistulas are aggressive vascular lesions causing SAH and progressive neurologic deficits. Prompt diagnosis and definite treatment are mandatory. Obliteration of the fistulas and/or leptomeningeal venous drainage should be the goal of treatment. Microsurgical procedures with/without endovascular intervention are the best choice of treatment.     

Sphenoid dural arteriovenous fistulas

Neurosurgical Review - Sphenoid wing dural AVFs represent a rare clinical entity. These lesions may be asymptomatic or present with focal neurologic deficits, intracranial venous hypertension, or...     

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.     

Multiple spinal dural arteriovenous fistulas

Summary Multiple spinal dural arteriovenous fistulas (DAVFs) have been rarely reported and only two such cases are found in the literature. A 71-year-old man complained of muscle weakness and hypesthesia in both legs and angiographically diagnosed as thoracic DAVF. The fistula was surgically treated, however, the symptoms recurred 14 months after the first treatment. Angiography revealed a new fistula in the lumbar region and this was also treated surgically. In the previously reported cases of multiple spinal DAVFs, the second fistulas were also diagnosed after the initial treatment. Symptomatic patients after the initial treatment of DAVF should be re-examined angiographically.     

Multiplicity of dural arteriovenous fistulas.

OBJECT: Dural arteriovenous fistulas (AVFs) are a well-known pathoanatomical and clinical entity. Excluding bilateral involvement of the cavernous sinus, multiple dural AVFs are rare, with isolated reports in the literature. The additional risk associated with multiplicity is unknown, although it has been claimed that there is a greater risk of hemorrhage at presentation. In a group of 284 patients with dural AVFs consecutively treated at a single center, the occurrence of multiplicity is investigated and its risk factors for hemorrhage are identified. METHODS: Among the 284 patients with both cranial and spinal dural AVFs, 20 patients with multiple fistulas were found. Nineteen (8.1%) of 235 patients with cranial AVFs had multiple cranial fistulas, and one (2%) of 49 patients with spinal AVFs harbored two spinal fistulas. Twelve patients were found to have a lesion at two separate sites, seven patients had them at three locations, and one patient had four fistulas, each at a different site. In the subgroup with multiple AVFs the percentage of hemorrhage at presentation was three times higher than in the entire group (p = 0.01). Cortical venous drainage in cranial fistulas was present in 84% of patients with multiple lesions compared with 46% of patients with solitary lesions (p < 0.005). CONCLUSIONS: Multiple dural AVFs are not rare. In this group of 284 patients it was found in 8.1% of all patients with cranial dural AVFs. Multiplicity was associated with a higher percentage of cortical venous drainage, a pattern of drainage reportedly yielding a higher risk for hemorrhage.     

Imaging of cerebral arteriovenous malformations and dural arteriovenous fistulas

Imaging plays a major role in the identification, grading, and treatment of cerebral arteriovenous malformations and cerebral dural arteriovenous fistulas. Digital subtraction angiography is the gold standard in the diagnosis and characterization of these vascular malformations, but advances in both magnetic resonance imaging and computed tomography, including advanced imaging techniques, have provided new tools for further characterizing these lesions as well as the surrounding brain structures that may be affected. This article discusses the role of conventional as well as advanced imaging modalities that are providing novel ways to characterize these vascular malformations.     

硬脊膜动静脉瘘的手术治疗

目的探讨硬脊膜动静脉瘘的手术方法及术后抗凝治疗。方法回顾性分析手术治疗的ＳＤＡＶＦ１９例,其中胸腰段１４例,骶部５例。手术方法包括：１４例胸腰段者于瘘口水平切断引流静脉。其中１１例可见硬膜外小供血动脉闭,同时电凝。骶部ＡＶＦ均于Ｌ５～Ｓ１水平切断引流静脉。９例行术后抗凝治疗。结果１６例术后脊髓功能改善,其中２例短暂好转后加重,经抗凝治疗后恢复。１例无改变,１例因过度抗凝出现术野血肿,１例残留ＡＶＦ。结论切断连接瘘口及冠状静脉丛的引流静脉是治疗ＳＤＡＶＦ的有效方法。术后抗凝可治疗及预防冠状静脉丛内血栓形成     

Classification schemes of cranial dural arteriovenous fistulas

The clinical presentation of dural arteriovenous fistulas (DAVFs), in particular the associated risk of intracranial hemorrhage, shows a strong correlation with their pattern of venous drainage. The two most commonly used and clinically accepted DAVF classifications are the Merland-Cognard classification and the Borden classification, both based on the morphology of the venous drainage. A revised classification that grades DAVFs through a combination of angiographic and clinical features has also been proposed. This article offers a review of these various classification schemes, and discusses their application to treatment decision making.     

Surgical treatment of intracranial dural arteriovenous fistulas

BACKGROUND: When considering the treatment strategies for dural arteriovenous fistulas (DAVFs), it is important to clarify the exact location of the fistula and venous drainage route from both DAVFs and normal brain tissue. DAVFs with leptomeningeal retrograde venous drainage carry a high risk of neurological deficits and require aggressive treatment. When AVFs involve the dural sinus, transvenous embolization via the transfemoral approach is usually the first choice of treatment. For DAVFs draining directly into the cortical veins without dural sinus involvement, transarterial embolization may be a curative treatment. However, when embolization is technically difficult or results in incomplete occlusion, surgical treatment is required. The purpose of the present study was to review our experience with surgical treatment of DAVFs. METHODS: The present series included 17 patients; 9 had DAVFs involving the dural sinus with leptomeningeal retrograde venous drainage and 8 had DAVFs draining directly into the cortical veins. For DAVFs involving the sinus, embolization of the diseased sinus by direct surgical exposure was performed in 8 patients, and surgical excision in one. For DAVFs draining directly into the cortical veins, interruption of the draining veins close to DAVFs was undertaken in 7 and surgical excision in 1. RESULTS: Complete obliteration of DAVFs was demonstrated in 16 patients. At final follow-up, 15 patients were asymptomatic and the other 2 showed clinical improvement. CONCLUSIONS: For DAVFs involving the dural sinus, direct operative sinus packing is indicated. For DAVFs directly draining into the cortical veins, surgical interruption of the draining veins is indicated.     

Endovascular management of spinal dural arteriovenous fistulas

Spinal dural arteriovenous fistulas (SDAVFs) represent the most frequent spinal arteriovenous malformation and have an ominous natural history if left untreated. In the present review, we describe the spinal vascular anatomy, pathophysiology and clinical manifestations of SDAVFs, and the current role of endovascular embolization in this type of lesion.     

Multiple spinal and cranial dural arteriovenous fistulas

Synchronous multiplicity of cranial and spinal dural arteriovenous fistulas (DAVFs) is known but uncommon. The authors report on a patient with the unusual finding of multiple cranial and multiple separate spinal DAVFs. The patient initially presented with vague visual symptoms in 2004. A cranial DAVF was identified along the left transverse sinus with cortical venous reflux and another DAVF was identified along the posterior part of the superior sagittal sinus with no cortical venous reflux. The first DAVF was treated both endovascularly and surgically and the second was left untreated. The follow-up angiogram showed multiple spinal DAVFs at the levels of C-1, C-2, and C-6 on the left side and at the C-3 level on the right side along with another cranial DAVF along the anterior part of the superior sagittal sinus with cortical venous reflux. A retrospective analysis of the digital subtraction angiogram and MR images suggested that the cervical spinal DAVFs were already present in 2004 (6 years previously). Multiple DAVFs, although rare, do exist and it is important to look for any evidence of their presence when evaluating patients with symptoms suggestive of arteriovenous fistulas.     

Acute management of ruptured arteriovenous malformations and dural arteriovenous fistulas

Arteriovenous malformations of the brain (AVMs) are a major cause of stroke in young, healthy individuals and present multiple diagnostic and therapeutic challenges, particularly in the acute setting. Although the flow hemodynamics, biology, epidemiology, and natural history of AVMs have been extensively studied, little data have been published on AVM surgery in the acute setting, and acute surgery has been claimed to possibly increase the risk of persistent neurological deficits. Although?it is usually preferable to defer AVM surgery for a few weeks or months, acute surgical (open and endovascular) management is essential in specific clinical and radiological settings.     

Surgical treatment of cranial arteriovenous malformations and dural arteriovenous fistulas

Microsurgical resection remains the treatment of choice for more than half of all patients with arteriovenous malformations (AVMs). It reduces the treatment window to a span of a few weeks and is curative. Careful patient selection, meticulous surgical planning, and painstaking technical execution of surgery are typically rewarded with excellent outcomes. For dural arteriovenous fistulas (DAVFs), microsurgical obliteration is often reserved for cases in which endovascular therapy either cannot be pursued or fails. When performed, however, microsurgical obliteration of DAVFs is associated with excellent outcomes as well. This article reviews the current state of microsurgical treatment of AVMs and 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 cranial arteriovenous malformations and dural arteriovenous fistulas

Pial arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs) are high-flow vascular lesions with abnormal communications between the arterial and venous system. AVMs are congenital lesions, whereas DAVFs are considered acquired lesions. Both can cause significant morbidity and mortality if they rupture and result in intracranial hemorrhage. The primary goal of treatment is to eliminate the risk of bleeding or at least decrease it. Because the epidemiology, clinical presentation, and classification of AVMs and DAVFs have been covered in previous articles in this issue, the authors only briefly touch on these subjects as they relate to endovascular treatment.     

Angiographic aspects and management of dural arteriovenous fistulas

The angiographic analysis of a dural arteriovenous fistula (AVF) is a determinant step in the evaluation of the lesion with regard to its prognosis and treatment. The clinical presentation of the dural AVFs is very dependent on the venous drainage, and the classification of these lesions draws attention to the venous drainage pattern, combining the clinical course and the venous drainage angiographic features. Dural AVFs with retrograde venous drainage into the leptomeningeal veins are associated with an increased incidence of intracranial hemorrhage, neurological deficits, and increased intracranial pressure allowing impairment of cognitive functions and dementia. Other risky findings are venous dilatations and dural sinus stenosis/occlusion. Different therapeutic approaches are available including noninvasive, endovascular, and surgical techniques. However, the treatment of dural AVFs should be considered in relation to the different types of lesions carrying different clinical presentation and prognosis. Prompt treatment allowing complete and permanent cure is mandatory in dural AVFs with an aggressive clinical course and/or with radiological findings predicting a severe prognosis.