Vertebral arteriovenous fistula associated with neurofibromatosis type I misdiagnosed as a giant aneurysm

Abstract

A 59-year-old man with neurofibromatosis type 1 (NF1) presented with bruits and neck pain due to a space occupying lesion in the right neck tissue. Digital subtraction angiography (DSA) showed an arteriovenous fistula (AVF) of the right extracranial vertebral artery (VA) with a giant venous pouch and an intracranial berry aneurysm of the right middle cerebral artery (MCA). First, the MCA aneurysm was surgically clipped, then the patient was treated by embolisation with coils. The coils were placed transarterially from the left VA resulting in a partial thrombosis of the venous pouch. Complete closure was achieved secondarily by retrograde transvenous catheterization. Etiology and treatment modalities are discussed.

Figure 1

Initial diagnosis DSA. A) Aortic arch arteriogram, RAO projection, late phase: the proximal segment (arrow) of the right VA was visualized, directed caudally and supplying the first pouch (25/30 mm) that was connected with another larger venous pouch (60 × 100 mm) located more cranially and displacing the right SA. B) Right subclavian arteriogram, a.p. view: shows the distorted proximal right VA (arrow), the “jet” into the first pouch (short white dotted arrow) and, in the later phase, the filling of the second pouch (long white dotted arrow). No venous exit is visualized. C) Left vertebral arteriogram, late phase: the flow in the right vertebral artery was reversed (dotted arrow), supplying the second larger pouch by steal phenomenon.

Figure 2

Transarterial embolisation. A) Left vertebral arteriogram, a.p. view: the microcatheter could not be navigated distal enough to reach the fistula site from the contralateral VA, so that detachable coils (arrow) had to be packed below the origin of the right PICA. B) Right deep cervical arteriogram, RAO projection: after occlusion of the proximal right VA by coils (arrow), check of collateral supply still revealed filling of the a.v. shunt (dotted arrows). C) Left vertebral arteriogram: follow-up after 6 months showed occlusion of the first pouch and reduction of the a.v. shunt but persistent filling of the fistula also via radicular arteries (dotted arrows).

Figure 3

Transvenous embolisation. A) Right deep cervical arteriogram, LAO projection, late phase: retrograde navigation of the guiding catheter (double arrows) into the venous outflow of the pouch (note: not visualized before!); arterial catheter placed in the right deep cervical artery (arrow), and microcatheter (white arrow) navigated into the large venous pouch. B) Same arteriogram post embo: attempts of retrograde navigation into the distal right VA for arterial occlusion of the fistula site failed: placement of detachable and fibered coils (arrow) within the single venous exit finally resulted into complete stagnation of a. v. shunting flow (double arrow).

Figure 4

Follow-up 3 months later. A) Left vertebral arteriogram, a.p. view: no filling of the venous pouch confirming persistent occlusion of the fistula (reduction of the venous sac revealed clinically). B) Right subclavian arteriogram, a.p. view: normal size of previously supplying anastomotic branches (ascending and deep cervical artery) and no remaining arteriovenous shunt.