Five (56%) of the 9 patients presented with intracranial hemorrhage. Clinical signs and symptoms in these patients are summarized in Table 1. In 8 patients, the fistulous connection was supplied by the posterior branch of the MMA and in 5 patients by branches of the OA. Less common feeding arteries included the PMA, the STA, the PAA, the MHT, and the SCA. All patients had exclusive cortical venous drainage (Cognard Type III).
In 6 patients (67%), total obliteration of the fistula was achieved immediately after Onyx embolization, and this was confirmed by a follow-up angiogram in 5, whereas the most recently treated patient has not yet undergone follow-up DSA. In 2 patients (Cases 3 and 6) near-total obliteration was demonstrated at follow-up. Surgery was recommended to one of these patients (Case 6) who had presented with intraparenchymal hemorrhage 2 years prior to embolization, but to date, he has refused further treatment. In the other patient (Case 3, a 73-year-old man who had presented with a temporal lobe hematoma), the faint, very delayed venous filling was considered of no clinical importance. Further MRI in this patient 1 year later did not suggest evidence of revascularization. Both patients are well and free of any symptoms 18 months (Case 3) and 13 months (Case 6) postembolization. Another patient underwent successful surgical disconnection of a lateral tentorial ("petrosal") DAVF a few weeks after a transarterial Onyx embolization attempt had failed to completely obliterate the fistula. Complete occlusion of the fistula was confirmed by immediate postoperative CTA, as well as MRA performed 6 months later. Clinical outcomes were excellent, with 89% of patients reporting complete resolution of initial presenting symptoms/signs. No complications occurred during or after treatment with Onyx.