Objective: This report focuses on the surgical management of aggressive intracranial dural arteriovenous fistulae (d-AVFs), which are defined as fistulae with arterialized leptomeningeal veins (red veins). Particular attention is paid to the accurate identification of the venous drainage pattern and to the choice of the proper treatment strategy.
Methods: Thirty-four consecutive patients with aggressive intracranial d-AVFs were treated between 1994 and 1998. Angiographic studies allowed the identification of two main types of aggressive lesions, i.e., d-AVFs with sinus drainage and reflow into leptomeningeal veins (12 patients), which we designated sinus fistulae, and d-AVFs drained exclusively by leptomeningeal veins without sinus interposition (22 patients), which we designated nonsinus fistulae. All patients underwent surgical treatment, which consisted of resection of the fistulous sinus tract in 12 cases of sinus fistulae and interruption of the draining veins at their dural origin in 22 cases of nonsinus fistulae. Surgical preparation via multistage transarterial embolization was required in all 12 cases of sinus fistulae and in 4 of 22 cases of nonsinus fistulae.
Results: The mortality rate was 0%, and there were no instances of lasting morbidity. Radioanatomic cures were achieved in all cases. There was no case of venous hypertension or venous infarction after resection of the affected sinus or interruption of the draining veins. No arteriovenous shunts recurred during the follow-up period.
Conclusion: Careful preoperative identification of the venous drainage pattern seems critical for planning of the correct surgical strategy to treat aggressive intracranial d-AVFs. If the fistula exhibits sinus drainage with reflow into leptomeningeal veins, surgical excision of the fistulous sinus segment represents a safe and definitive treatment option. In these cases, the affected sinus may be safely removed, provided that preoperative angiograms demonstrate participation of the sinus in drainage of the lesion, indicating that the sinus is nonfunctional. Conversely, if the fistula exhibits pure leptomeningeal drainage, the sinus does not participate in drainage of the lesion and cannot be excised. In these cases, the best treatment involves interruption of the draining veins at the point at which they exit the dural wall of the sinus. This simple easy treatment has been proven to be safe and highly effective in permanently eliminating arteriovenous shunts.