Embolization of intracranial arteriovenous malformations with ethylene-vinyl alcohol copolymer (Onyx)

Abstract

Background and purpose: Endovascular therapy of intracranial arteriovenous malformations (AVMs) is increasingly used. However, it is still under discussion which embolic material is optimal. We report our experience in the treatment of AVMs with ethylene-vinyl alcohol copolymer (Onyx).

Materials and methods: Between July 2002 and January 2008, brain AVMs were embolized with Onyx in 82 consecutive patients in our department. There were 41 females and 41 males with a mean age of 44.2 years (range, 15-85 years). Clinical presentation included symptoms due to intracerebral hemorrhage (n = 37), seizures (n = 18), nonhemorrhagic neurologic deficits (n = 8), headaches (n = 9), or incidental symptoms (n = 10). According to the Spetzler-Martin scale, 59 AVMs were grades I-II, 16 were grade III, and 7 were grades IV-V.

Results: Complete obliteration at the end of all endovascular procedures was achieved in 20/82 patients (24.4%), with an average of 75% (range, 30%-100%) volume reduction. A mean of 2.9 (range, 1-10) feeding pedicles was embolized per patient, whereas an average of 2.6-mL Onyx was used per patient. Procedure-related permanent disabling morbidity was 3.8%, whereas mortality was 2.4%.

Conclusions: The overall initial complete obliteration rate of intracranial AVMs with Onyx embolization is relatively high, compared with other embolic agents, with evidence of stability with time. Morbidomortality rates due to AVM embolization as a single treatment method or as a part of a multimodality treatment should be further assessed regarding the natural course of the disease.

Fig 1.

A 48-year-old male patient with an SM grade II AVM in the left cerebellar lobe. A and B, Vertebral angiogram (lateral view, arterial and late venous phase) shows arterial supply to the AVM from feeders of the left posterior inferior cerebellar artery with superficial venous drainage. C, Unobstructed image illustrates a solid Onyx cast after the embolization. D, Left vertebral angiogram (lateral view, venous phase) illustrates complete AVM occlusion after embolization through a single pedicle.

Fig 2.

A 29-year-old female patient with an SM grade IV AVM in the right occipital lobe. A, Vertebral angiogram (lateral view) shows arterial supply from multiple feeders arising mainly from the right posterior artery with superficial venous drainage. B, Right internal carotid artery angiogram (lateral view) shows additional arterial supply to the AVM from feeders of the middle cerebral artery. C, Unobstructed image illustrates a solid Onyx cast after the embolization. D and E, Control right vertebral and carotid artery angiograms (lateral view) at 6 months after embolization illustrate persistence of complete occlusion with no evidence of recanalization. F, MR image (time-of-flight, axial) at 6 months after embolization reveals complete occlusion of the AVM without evidence of reperfusion.

Fig 3.

A 53-year-old male patient with an SM grade I AVM in the right frontal lobe. A, Right internal carotid angiogram (lateral view) shows arterial supply to the AVM from feeders of the right pericallosal artery with superficial venous drainage. B, Right internal carotid angiogram (lateral view, early venous phase) illustrates complete AVM occlusion after embolization. C, Postembolization cerebral CT scan (axial) illustrates the Onyx cast with subtotal penetration inside the AVM nidus. D, Control right carotid artery angiogram (lateral view) at 4 months after embolization demonstrates partial recanalization of the AVM nidus with reconstitution of early venous drainage.