Brain AVM embolization with Onyx

Abstract

Background and purpose: To report the initial experience by using a new liquid embolic agent (Onyx) for embolization of brain arteriovenous malformations (AVMs).

Methods: Between May 2000 and December 2005, 44 patients with brain AVMs were embolized with Onyx. There were 18 women and 26 men with a mean age of 42.4 years (median 44, range 14-71 years). Clinical presentation included seizures in 26 patients (59%), hemorrhage from the AVM in 13 patients (30%), subarachnoid hemorrhage from a concomitant aneurysm in 3 patients (7%), visual disturbances in 1 patient (2.3%), and in 1 patient (2.3%) the AVM was an incidental finding. Mean estimated size of the AVM was 3.9 cm (median 4, range 2-7 cm).

Results: In 44 patients, 52 embolization procedures were performed with 138 feeding pedicles embolized, ranging from 1 to 7 per patient. Average estimated size reduction was 75% (median 80%, range 40%-100%). Total obliteration was achieved in 7 AVMs (16%), and partial embolization was followed by surgery in 10 patients and by radiosurgery in 20 patients. Complications occurred in 6 patients, leading to death in 1 patient (mortality 2.3%) and to permanent disability in 2 patients (morbidity 4.6%).

Conclusion: Onyx is feasible and safe in the embolization of brain AVMs. Complete obliteration can be achieved in small AVMs. Large AVMs can be adequately reduced in size for additional surgical or radiosurgical treatment.

Fig 1.

A 44-year-old man with seizures and a left parietal AVM. A, A 3.5-cm left parietal AVM with superficial and deep venous drainage (Spetzler and Martin grade IV). B, The AVM shows 80% obliteration with a single Onyx injection of 4.8 mL in 64 minutes. C, Onyx cast after embolization. D, Complete obliteration of the AVM 2 years after gamma knife radiosurgery.

Fig 2.

A 28-year-old man with a 3-cm right parietooccipital AVM. A, The AVM has 2 main feeders. B, Complete obliteration of the AVM with 2 injections of Onyx (total of 3.5 mL). C, Cast of Onyx.

Fig 3.

A 37-year-old woman with small high-flow AVM (pial fistula). A, Large arteriovenous shunt from anterior cerebral artery. B, Microcatheter just proximal to the shunt; from this point Onyx 34 was slowly injected. C, Onyx cast after injecting 3.4 mL in 16 minutes. D, Complete closure of the fistula at 6 weeks follow-up angiogram.

Fig 4.

Right temporal AVM in a 28-year-old woman with seizures. Complete occlusion occurred with a single 62-minute Onyx injection of 7.8 mL. A, Oblique right internal carotid angiogram shows AVM fed by the anterior temporal artery and draining via a large superficial vein (white arrows) and a small superficial vein (black arrow). B, Onyx cast after 12 minutes slow injection. C, Onyx cast after 28 minutes. D, Onyx cast after 62 minutes. The AVM is completely occluded, including the proximal parts of the draining veins (same arrows as in A).

Fig 5.

A 31-year-old man with seizures and right temporal AVM, embolized with Onyx. A, Right temporal AVM with superficial venous drainage. B, C, Small nidal remnant with open draining vein after subtotal obliteration. D, Hemorrhage 3 days after embolization. E, Angiogram after hemorrhage shows nidal remnant with no apparent venous drainage. F, Angiogram after surgery demonstrates complete removal.