Direct microsurgery of dural arteriovenous malformation type carotid-cavernous sinus fistulas: indications, technique, and results.

Abstract

There is a subgroup of patients with Barrow Type D carotid-cavernous sinus fistulas (CCFs) who have progressive neurological deficits despite endovascular attempts at obliteration. To effectively arrest the progression of neurological deficits, especially visual loss, these patients require direct operative intervention. We have used a direct approach to such lesions, which comprehensively occludes all fistulous connections of the CCF. We present a series of nine patients with Type D CCFs for which attempts at endovascular embolization failed and that, because of persistent symptoms, required surgical intervention. These lesions characteristically had extensive multiple external carotid artery feeders, often bilateral, in addition to the internal carotid artery feeders. The operative approach used was a combined extra- and intradural full exposure of the cavernous sinus and its contents, with identification and direct obliteration of all arterial input and selective ablation of the venous outflow from the cavernous sinus. All nine patients experienced resolution of their symptoms, and complete ablation of the lesions, as demonstrated by postoperative angiography, was achieved. Transient diplopia and trigeminal hypesthesia was observed in all nine patients, which resolved by 6 months postoperatively. One patient suffered from a temporary hemiparesis and another from permanent hemiparesis. There were no deaths related to surgery in this series. Patients with Type D CCFs who have persistent, progressive neurological deficits after failed endovascular attempts at obliteration may be treated by a direct surgical approach to ablate the fistulas. The pertinent anatomic concepts, indications for surgery, and operative techniques that are different from previously described methods are discussed.