Surgical and endovascular flow disconnection of intracranial pial single-channel arteriovenous fistulae

INTRODUCTION: Intracranial pial single-channel arteriovenous (AV) fistulae are rare vascular lesions of the brain. They differ from AV malformations i n that they lack a true "nidus" and are composed of one or more direct arte rial connections to a single venous channel. They often are associated with a venous varix because of their high-flow nature. The pathological aspects of pial AV fistulae arise from their high-flow dynamics; therefore, we thi nk that disconnection of the AV shunt is enough to obliterate the lesion, a nd that lesion resection is unnecessary. Flow disconnection can be accompli shed via surgical or endovascular means. Certain lesions have angiogeometri c configurations, however, that are unfavorable for endovascular treatment. We reviewed the experience in our combined neurosurgical and neuroendovasc ular unit in the treatment of patients with pial single-channel AV fistulae . METHODS: From 1991 to 1999, the combined neurovascular unit at the Massachu setts General Hospital treated nine consecutive patients with nontraumatic intracranial pial single-channel AV fistulae. Carotid-cavernous fistulae an d vein of Galen malformations were excluded from this analysis. The combine d neurovascular team planned the treatment strategy for each patient on the basis of the anatomic location and the angiogeometry of each lesion. We re trospectively reviewed the medical records, office charts, operative report s, endovascular reports, and x-rays for each patient. Radiographic outcome was assessed by use of posttreatment angiography. Clinical outcome was asse ssed by an independent nurse practitioner. RESULTS: A treatment strategy of flow disconnection was used in all nine pa tients and was accomplished surgically in six patients, endovascularly in t wo patients, and by combined techniques in one patient. All nine lesions we re completely obliterated as demonstrated radiographically, including oblit eration of the venous varices associated with three of the lesions. With a mean long-term clinical follow-up of 3.2 years (range, 0.3-8.4 yr), four pa tients were neurologically excellent with no deficits, two patients had pre treatment neurological deficits that did not worsen after treatment, one pa tient had transient dysphonia and dysphagia postoperatively that resolved, one patient had mild weakness after treatment, and one patient had moderate homonymous hemianopia after treatment. CONCLUSION: Single-channel pial AV fistulae can be treated by a strategy of flow disconnection. Resection of the lesion is not necessary. Flow disconn ection can be accomplished either surgically or endovascularly; however, ce rtain angiogeometric configurations are more favorable for surgical treatme nt. An experienced combined neurosurgical and neuroendovascular team can ca refully determine the most appropriate treatment modality on the basis of p atient-specific and angiospecific factors.