TENTORIAL DURAL ARTERIOVENOUS FISTULAE

Abstract

Tentorial dural arteriovenous fistulae (DAVF) are rare, have a high risk of hemorrhage, often cannot be obliterated endovascularly, and frequently require microsurgical interruption of the draining vein. We differentiated these fistulae into six types and developed specific operative strategies on the basis of these types. During a 9-year period, 31 patients underwent microsurgical treatment for tentorial fistulae: seven galenic DAVF, eight straight sinus DAVF, three torcular DAVF, three tentorial sinus DAVF, eight superior petrosal sinus DAVF, and two incisural DAVF. The posterior interhemispheric approach was used with galenic DAVF; the supracerebellar-infratentorial approach was used with straight sinus DAVF; a torcular craniotomy was used with torcular DAVF; the supratentorial-infraoccipital approach was used with tentorial sinus DAVF; the extended retrosigmoid approach was used with superior petrosal sinus DAVF; and a pterional or subtemporal approach was used with incisural DAVF. Angiographically, 94% of the fistulae were obliterated completely. Four patients had transient neurological morbidity, none had permanent neurological morbidity; and there was no operative mortality (mean follow-up, 4.2 yr). Tentorial DAVF can be differentiated on the basis of fistula location, dural base, associated sinus, and direction of venous drainage. The operative strategy for each type is almost algorithmic, with each type having an optimum surgical approach and an optimum patient position that allows gravity to retract the brain, open subarachnoid planes, and shorten dissection times. No matter the type, the fistula is treated microsurgically by simple interruption of the draining vein.