Surgical removal of embolic material after its unexpected migration through extracranial-intracranial anastomosis in the treatment of Barrow Type D carotid-cavernous fistula: case report.

Endovascular occlusion via the transvenous route is the favored treatment for indirect carotid-cavernous fistulas (CCFs). However, transarterial embolization can be used as an alternative method in patients with an inaccessible venous route. The authors present the case of a 49-year-old woman with a 2-month history of chemosis and proptosis in her right eye. Angiography demonstrated a Barrow Type D CCF. Transarterial Onyx embolization through the accessory meningeal artery was performed after an unsuccessful transvenous approach. Unexpected Onyx migrations to the cerebral arteries were detected while injecting the embolic material. Three hours after failed attempts to retrieve the Onyx cast endovascularly, it was microsurgically removed from the right middle cerebral artery. To the authors' knowledge, this is the first report of the surgical removal of Onyx from a normal cerebral artery.