- A catheter-based procedure that closes off abnormal connections between arteries and veins from inside the vessels
- A microcatheter is navigated into the small arteries feeding the malformation under high-resolution X-ray guidance
- A liquid embolic agent (such as Onyx) is injected, hardening within the abnormal vessels and shutting them down permanently
- May completely cure the lesion, or may be staged across more than one session for larger malformations
- Often combined with microsurgical removal or stereotactic radiosurgery as part of a planned, multistep treatment
- Performed under general anesthesia, typically with a short hospital stay
