VascularTentorial dural arteriovenous fistulas
Introduction
Intracranial dural arteriovenous fistulas constitute approximately 10% to 15% of all intracranial arteriovenous malformations, predisposed to occupation at the cavernous, transverse, sigmoid, and parasagittal sinuses [3], [30]. Their fistulas are in the sinus wall. Tentorial dural arteriovenous fistulas are a unique subset of intracranial dural arteriovenous fistulas. Their fistulas are in the tentorial dura mater rather than in the sinus wall, although TDAVFs included those lesions that drain into the straight and superior petrosal sinuses [33]. Tentorial dural arteriovenous fistulas are relatively rare, accounting for 4% to 8% of intracranial dural arteriovenous fistulas. Tentorial dural arteriovenous fistulas, however, are one of the most life-threatening vascular lesions, because they portend aggressive poor behavior and natural history. Moreover, TDAVFs are deep-seated lesions with complicated supplying arteries and draining veins, making them not only difficult in their management, but also controversial regarding the optimal treatment strategy [1], [2], [3], [11], [14], [16], [22], [23], [27], [30], [31], [32], [33], [34], [35], [36], [38], [41], [42], [43], [44], [45], [46]. In this study, we present 5 cases of TDAVFs and our management rationale in conjunction with reviewing the relevant literature.
Section snippets
Materials and methods
A consecutive series of 5 patients with TDAVFs were evaluated and treated in our department between June 2002 and May 2003. Their information was prospectively maintained, and a retrospective analysis of patient records, neuroimaging, and follow-up data were conducted. There were 3 females and 2 males. Patients' ages ranged from 25 to 52 years, with an average of 38 years. The duration (from the appearance of symptoms to the diagnosis) was from 2 months to 2 years, with a mean of 9.8 months.
Neuroimaging workup
Computed tomography scanning was done in 3 patients, revealing SAH (2 cases) and high-density cystic mass in the cerebellopontine angle (1 case) (Fig. 1). Magnetic resonance imaging was performed in 5 patients, demonstrating dilated and tortuous flow voids in the tentorial incisura, surface of the brainstem, and cerebellum on both T1- and T2-weighted images. There was an aneurysmal cyst in 2 cases. The edema of the surrounding cerebellar and brainstem parenchyma was detected on T2-weighted
Classification of TDAVFs
All lesions in the series were Borden type 3, which means that the lesions have retrograde leptomeningeal venous drainage documented angiographically [6] (Fig. 3). According to Picard's classification [40], which focused on lesions located exclusively in the tentorium, as evidenced by the particular patterns of venous drainage and fistulas, 3 types of TDAVFs were categorized as follows:
- 1.
Tentorial marginal type (3 cases in the series, Fig. 4). The fistulas are located along the free edge of the
Treatment protocol
All patients were evaluated by a group composed of neurosurgeons and endovascular specialists for the assessment and suitability of the treatment options. Because most cases in this series had multiple and complicated retrograde leptomeningeal venous drainage, transarterial embolization was chosen as first-line therapy. If endovascular treatment was unsuccessful or technically impossible, the patient was evaluated for microsurgical treatment. Therefore, transarterial embolization was used
Results and follow-up study
One patient suffered from cerebellar infarction, confirmed by CT, after preoperative transarterial intervention and was improved by medication. All patients tolerated surgical procedures very well with no surgical mortality and morbidity. Presurgical symptoms and signs have improved or disappeared in 4 patients and were unchanged in 1 patient. Digital subtraction angiography was taken in 3 patients 9, 14, and 210 days after operation, demonstrating the disappearance of the fistulas and abnormal
Discussion
The natural history, clinical manifestations, and outcome of dural arteriovenous fistulas heavily depend upon their venous drainage patterns [1], [2], [3], [4], [6], [8], [11], [12], [14], [17], [24], [25], [30], [31], [32], [33], [34], [35], [38], [41], [45]. Because TDAVFs most often belong to the Borden type 2 or 3 lesions, that means there is a presence of retrograde leptomeningeal venous drainage with or without dural sinus drainage [6]. Under long-term effect of intracranial venous
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