To assess safety and efficacy of ONYX treatment for cAVM:

The main objective of this study is to assess the safety at 1 month after any embolization session and the efficacy at:

• 12 months post last embolization in case of treatment with embolization only
• 12 months after additional treatment with neurosurgery
• 36 months after additional treatment with radiosurgery

Inclusion Criteria:

• The patient presents a cerebral AVM (not already treated) that can be treated by embolization with Onyx whether or not associated with a cyanoacrylate based adhesive,
• The patient is at least 6 years old.

Exclusion Criteria:

• During the treatment period for his/her cerebral AVM, the patient participates in a study assessing another medical device, another procedure or a drug.
• The patient and/or his/her legal representative (if applicable) refuses to give his/her consent to the collection and processing of data required by the centralized follow-up. For patients who refused collection of their personal data, only, the reason for non inclusion and date of implantation will be documented.
• Any condition that could prevent follow-up of the patient.

All the patients from participating centres for whom a cerebral AVM (not already treated) has to be treated (whatever treatment method anticipated) and who do not object to the collection and transmission of data concerning them, will be included in the so-called "screened" population.

No individual participant data will be available