Transarterial embolization for convexity dural arteriovenous fistula with or without pial arterial supply: A report of four patients

Abstract

Background: Convexity dural arteriovenous fistulae (dAVF) usually reflux into cortical veins without involving the venous sinuses. Although direct drainage ligation is curative, transarterial embolization (TAE) may be an alternative treatment.

Case description: Between September 2018 and January 2021, we encountered four patients with convexity dAVFs. They were three males and one female; their age ranged from 36 to 73 years. The initial symptom was headache (n = 1) or seizure (n = 2); one patient was asymptomatic. In all patients, the feeders were external carotid arteries with drainage into the cortical veins; in two patients, there was pial arterial supply from the middle cerebral artery. All patients were successfully treated by TAE alone using either Onyx or N-butyl cyanoacrylate embolization. Two patients required two sessions. All dAVFs were completely occluded and follow-up MRI or angiograms confirmed no recurrence.

Conclusion: Our small series suggests that TAE with a liquid embolic material is an appropriate first-line treatment in patients with convexity dAVFs with or without pial arterial supply.

Keywords: Convexity; Dural arteriovenous fistula; Pial artery; Transarterial embolization.

Figure 1:

Representative Case 1 (a) T2-weighted image shows flow void in the medial aspect of the left occipital lobe (white arrow). (b and c) The left common carotid angiograms (b: frontal view and c: lateral view) confirm a dural arteriovenous fistula (dAVF) fed by the mastoid branch of the left occipital artery (OA) (white arrowhead) and middle meningeal artery (MMA) (black arrowhead) on the left occipital convexity with cortical venous reflux (CVR, white arrow). The black arrow indicates the shunt site. (d and e) The right common carotid angiograms (d: frontal view and e: lateral view) reveal the dAVF (white arrow) supplied by the mastoid branch of the right OA (white arrowhead) and MMA (black arrowhead) with the drainage into the occipital cortical vein. The black arrows indicate the shunt site. (f) Schema of the angioarchitecture delineating the feeding arteries (red), CVR (blue), and sinus (light blue). (g) Postoperative magnified X-ray (frontal view) demonstrates that the CVR, the mastoid branch of the left OA, and the posterior branch of the MMA were filled with Onyx (black arrowhead). The white arrowhead indicates the injection point on the MMA (tip of the balloon catheter). (h) Schematic drawing of the Onyx embolization material (black), feedeing arteries (red), CVR (blue), and sinus (light blue). (i and j) Postoperative left (i) and right (j) common carotid injections (frontal view) identify complete disappearance of the dAVF.

Figure 2:

Representative Case 2: (a) T2-weighted image shows dilated cortical vessels (white arrows) in and around the left central sulcus. (b and c) Selective right external carotid angiograms (b: frontal view and c: lateral view) identified a dural arteriovenous fistula (dAVF) on the left parietal convexity. It was fed from the right anterior (black arrowhead) and posterior (white arrowhead) branch of the middle meningeal artery (MMA). Drainage was into a dilated Rolandic vein (white arrow). Black arrows indicates the shunt site. (d and e) Selective left external angiograms (D: frontal view and E: lateral view) also reveal the arteriovenous shunt arising from the left anterior (black arrowhead) and posterior (white arrowhead) branch of the MMA with cortical venous reflux (CVR) (white arrows). The black arrows indicate the shunt site. (f) Selective left internal carotid angiogram (frontal view) demonstrates pial arterial supply from the left middle cerebral artery (MCA). Black and white arrows indicate the shunt site and CVR, respectively. (g) Schema of the angioarchitecture delineating the feeding arteries from the external carotid arteries (red), the pial arterial supply from the left MCA (pink), CVR (dark blue), and the sinus (light blue). (h) X-ray (frontal view) demonstrates CVR and the bilateral MMAs filled with NBCA. (i) Schematic drawing of NBCA distribution (black). Black arrowheads indicate the 5 NBCA injection sites. Red, pink, dark blue and light blue also indicate feeding arteries, the pial arterial supply, CVR and the sinus respectively. (j and k) Selective right (j: lateral view) and left external (k: lateral view) carotid angiograms confirming complete obliteration of the dAVF immediately after the second TAE session. (l and m) Selective left internal carotid angiograms (lateral views) demonstrate a slight residual shunt flow (white arrows) from the left MCA just after the second session (l), and complete disappearance of the shunt 6 months after the procedures (m).