Assessment of Therapeutic Access Routes for Endovascular Therapy of Cavernous Sinus-dural Arteriovenous Fistula

Abstract

Objective: The usefulness of endovascular treatment for cavernous sinus (CS)-dural arteriovenous fistula (dAVF) has been established. As the first choice of endovascular intervention for CS-dAVF, transvenous embolization (TVE) is generally performed, and the inferior petrosal sinus (IPS) is usually selected as the main access route to the affected CS because of its accessibility. However, the angiographical pattern of the CS varies among individuals. In some cases, it is difficult to access the affected CS via the ipsilateral IPS because of thrombosis, hypoplasia, or aplasia. Therefore, in some cases, alternative venous access routes are needed for TVE. Methods: A retrospective study was performed with 27 patients diagnosed with intracranial dAVF who underwent endovascular embolization at our institution. Among these, the data of nine patients with CS-dAVF treated by endovascular intervention were analyzed retrospectively in this study. We reviewed the endovascular access routes for CS-dAVF treatment based on anatomical and embryological considerations. Results: The most common complaint was diplopia, followed by exophthalmos and chemosis. There was no hemorrhagic onset. Cortical venous reflux (CVR) was recognized angiographically in six patients. The IPS on the affected side was angiographically occluded in four patients. TVE was attempted first in all patients. In five patients where the ipsilateral IPS was patent, TVE was successfully performed via the ipsilateral IPS. In four patients where the ipsilateral IPS was occluded, microcatheter access to the affected CS via the ipsilateral IPS was unsuccessful. The following alternative approach routes were selected: the superficial temporal vein, facial vein, direct puncture of the superficial middle cerebral vein (SMCV), and ascending pharyngeal artery (APA) for transarterial intravenous embolization (TAIV). The CS-dAVF had disappeared in all patients at the final follow-up examination. In the case of difficult access, compartment formations of the intracavernous sinus were recognized. Compartment formation due to the anatomical and embryological differences of the intracavernous structure may have influenced the ability of the catheter to reach the affected shunted pouch. Conclusions: In cases where the approach via the ipsilateral IPS was difficult, alternative access routes were effective for the required embolization. It is extremely important to fully understand the angioarchitecture, location of the shunted pouch, and compartments of the CS for successful endovascular treatment. Anatomical and developmental CS considerations may be useful for better access route selection.