Persistent trigeminal artery aneurysm rupture inducing a carotid-cavernous fistula: its presentation and management. Illustrative case.

Background: A carotid-cavernous fistula (CCF) is a well-recognized entity resulting from an abnormal connection between the internal carotid artery (ICA) or external carotid artery and the cavernous sinus. Typical CCF symptomology includes proptosis, chemosis, orbital bruit, headache, facial pain, and cranial nerve (CN) palsies. While CCFs most often occur posttraumatically, they can also occur spontaneously, secondary to cavernous ICA aneurysm rupture. Very rarely, they can occur secondary to the rupture of an anomalous persistent trigeminal artery (PTA) aneurysm.

Observations: Herein, the authors describe the case of a 54-year-old woman who presented with a CN VI palsy and headache due to a CCF secondary to a PTA aneurysm rupture. The CCF was ultimately treated via coil embolization of the aneurysm and the parent PTA vessel.

Lessons: Though such occurrences are rare, clinicians should be vigilant in assessing for the presence of a PTA in patients with a CCF, as a PTA-associated CCF requires unique treatment considerations. In some cases where the PTA plays a crucial role in the posterior circulation supply, preservation of the parent vessel PTA is crucial. However, in cases in which an adequate posterior circulation collateral supply exists, embolization of the aneurysm and the parent vessel PTA is a reasonable treatment option for fistula closure. https://thejns.org/doi/10.3171/CASE24287.