Intraoperative cone-beam computed tomography contributes to avoiding hypoglossal nerve palsy during transvenous embolization for dural arteriovenous fistula of the anterior condylar confluence.

Abstract

Dural arteriovenous fistula of the anterior condylar confluence (ACC-DAVF) is a rare subtype of DAVFs that occurs around the hypoglossal canal. Transvenous embolization (TVE) with coils has been performed for most ACC-DAVFs with a high clinical cure rate. However, some reports call attention to hypoglossal nerve palsy associated with TVE due to coil mass compression of the hypoglossal nerve caused by coil deviation from the ACC to the anterior condylar vein (ACV). Herein, we report a case of ACC-DAVF in which an intraoperative cone-beam computed tomography (CT) contributed to avoiding hypoglossal nerve palsy. A 74-year-old man presented with left pulse-synchronous tinnitus. An angiography detected left ACC-DAVF mainly supplied by the left ascending pharyngeal artery and mainly drained through the ACV. The two fistulous points were medial side of the ACC and the venous pouch just cranial of the ACC. We performed TVE detecting the fistulous points by contralateral external carotid angiography (ECAG). The diseased venous pouch and ACC were packed with seven coils but a slight remnant of the DAVF was recognized. Because a cone-beam CT revealed that the coil mass was localized in the lateral lower clivus osseous without deviation to the hypoglossal canal, we finished TVE to avoid hypoglossal nerve palsy. Postoperatively, no complication was observed. No recurrence of symptoms or imaging findings were detected during a five-month follow-up period. An intraoperative cone-beam CT contributed to avoiding hypoglossal nerve palsy by estimating the relationship between the coil mass and the hypoglossal canal during TVE of ACC-DAVF.