Endovascular Treatment of Brain Arteriovenous Malformations Using Onyx: Preliminary Results of a Prospective Multicenter Study

Abstract

The main final goal of the treatment of brain AVMs is to prevent bleeding and to obtain a complete occlusion of the nidus. The strategy of treatment of brain arteriovenous malformations (AVM) has to be defined by a multidisciplinary team and will usually combine several modalities (surgery, radiosurgery, embolization). Embolization is generally the first step of treatment. Occasionally embolization is able to completely occlude a small AVM.

Otherwise embolization is the first step before surgery or radiosurgery. Several embolic agents have been proposed for embolization of brain AVMs like particles or cyanoacrylates. The main disadvantage of particles is the high frequency of recanalization.

The cyanoacrylates are probably more appropriate, providing a permanent occlusion. However, due to the polymerizing characteristics of the glue, the time of injection is relatively short (few seconds or minutes) and a complete or substantial occlusion of the nidus is difficult to obtain, especially in the case of medium or largesized AVMs.

Onyx is a nonadhesive liquid polymer made of a mixture of ethylene-vinyl-alcohol copolymer and dimethylsulfoxide. The theoretical advantage of a nonadhesive liquid is to eliminate the risk of gluing the microcatheter and subsequently to perform a more durable injection with a larger amounts of agent delivered in a single injection.

Several French centers have undertaken a prospective, multicentric study to evaluate the clinical value of Onyx in embolization of brain AVMs. As required, 50 patients were included. Preliminary results are presented regarding the first 48 patients, the last 2 patients being included after writing of this paper.

The treatment is now completed in 15 patients. As expected, it was possible with Onyx to perform long duration injections (5 to 70 minutes with a mean of 34 minutes).

Volumes injected per session were also important (0.25 to 6 ml with a mean of 1.6 ml). According to the clinical experience of the centers, duration and volume injected were most important with Onyx than with cyanoacrylates. Out of the 15 patients for whom embolization is now completed, 14 had a percentage of occlusion of the nidus greater than 60% (with 2 complete occlusion).

Keywords

brain arteriovenous malformation embolization Onyx

Get full access to this article

View all access options for this article.

References

Cognard

Spelle

: Pial arteriovenous malformations. In: Forsting

(Ed), Intracranial malformations and aneurysms, Springer, Berlin, Heidelberg 2004: 39–100.

Jahan

Murayamaet

Y AL

: Embolization of arteriovenous malformations with Onyx: clinicopathological experience in 23 patients. Neurosurgery 4: 984–997, 2001.

Moret

Hammani

: Traitement des malformations artérioveineuses cérébrales par l'Onyx: à propos d'une série de 94 patients. J. of Neuroradiology 32: 86.

Picard

Da Costa

: Acute spontaneaous hemorrhage after embolization of brain arteriovenous malformation with n-butyl-cyanoacrylate. J Neuroradiol 28: 147–165, 2001.

Debrun

Aletich

: Embolization of the nidus of brain arteriovenous malformations with N-Butyl-Cyanoacrylate. Neurosurgery, 40: 112–121, 1997.

Murayama

Viñuela

: Nonadhesive embolic agent for cerebral arteriovenous malformations: preliminary histopathological studies in swine rete mirabile. Neurosurgery 43: 1164–1175, 1998.

Chaloupka

Huddle

: A re-examination of the angiotoxicity of superselective injection of DMSO in the swine rete embolization model. AJNR Am J Neuroradiol 20: 401–410, 1999.

Frizzel

Fisher

: Cure, morbidity and mortality associated with embolization of cerebral arteriovenous malformations: a review of 1246 patients in 32 series over a 35-year period. Neurosurgery 37: 1031–1040, 1995.

Wikholm

Lundqvist

: Embolization of cerebral arteriovenous malformations, part I. Technique, morphology, and complications. Neurosurgery 39: 448–459, 1996.