Anatomical localization of the cavernous sinus dural fistula by 3D rotational angiography with emphasis on clinical and therapeutic implications.

BACKGROUND AND PURPOSE

Carotid cavernous sinus dural arteriovenous fistulas (CSDAVFs) are presumed to be located within the walls of the cavernous sinus, however the exact fistulous site has not yet been studied by angiographic or anatomical methods. The present study aimed to localize CSDAVFs with the help of 3D rotational angiography (RA) and correlated the observations with clinical and angiographic findings.

MATERIALS AND METHODS

The CSDAVFs were categorized as dural, extradural or osseous based on the site of convergence of feeders into the venous sac. Extradural CSDAVFs were further subcategorized into posteromedial, posterolateral and anterior subtypes, depending on proximity to a possible venous plexus. This classification was correlated with various clinical presentations and angiographic subtypes.

RESULTS

Thirty-seven patients were included in the final analysis. The sac was identified in all the patients and the mean sac size of the fistula was small (<4mm). Dural type was associated with exclusive cortical venous drainage. Extradural anterior CSDAVF showed tendency towards younger age predilection. Extradural posterolateral CSDAVF was more often associated with initial oculomotor nerve palsy and this observation was statistically significant. Discordancy between the location of the fistula and the side of clinical affection was observed in midline fistulas such as osseous CSDAVF and posteromedial type of extradural CSDAVF.

CONCLUSIONS

CSDAVF is a heterogeneous vascular disorder involving the sphenoclival bone, extradural space and dura, homologous to the epidural-dural shunts of vertebra with a common clinical presentation of orbital manifestations. Preoperative localization of the fistula could explain enigmatic observations and potentially simplify its interventional management.