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Onyx Embolization

About Onyx Embolization

The body’s circulatory system has a delicate balance of blood flow from arteries, to the heart, then to the tissues, then to the veins and back to the heart. If you have an arteriovenous fistula (AVF), there is an abnormal pathway directly from an artery to a vein. Another condition, arteriovenous malformation (AVM), is a group of abnormal blood vessels (arteries and veins). AVF is found in the covering of the brain or spinal cord while AVM can found in the tissues throughout the body or in the brain. Bleeding from a burst AVM or AVF can cause disability or death.

Neurosurgeons of New Jersey is one center offering both established and innovative surgical treatments for brain AVMs and AVFs. Onyx embolization is one such treatment. In this procedure, surgical glue is placed at the site of the AVM or AVF to close the opening to prevent rupture and leaking.

Goal of Onyx Embolization

Successful embolization blocks abnormal blood flow from the artery into the vein in the case of AVF, or reduces pressure in the AVM. This significantly reduces the risk of rupture. The liquid Onyx agent, which hardens upon contact with blood, fills up space at the appropriate site to prevent abnormal blood flow. This kind of embolization is considered minimally invasive, as it involves the navigation of the surgical glue Onyx through the major arteries of the body and does not require a craniotomy.

How Onyx Embolization Is Performed

In order to reach the AVF or AVM, your doctor must first place a microcatheter and wire at the site. The catheter and wire are first inserted into a major artery near your groin. Using X-ray imaging for guidance, the doctor navigates the catheter through your body to the abnormality. Your surgeon will put the end of the wire to where the Onyx must be placed.

Your doctor will inject a liquid solvent and then Onyx into the area through the wire. Contact with blood causes the mixture to become solid and spongy. Once the area is filled up with the Onyx mixture, your doctor will remove the catheter and wire. Sometimes this procedure also requires a surgical balloon which follows the same route through your body like the catheter and wire. The balloon is inflated to block the access point of the blood flow so the liquid Onyx cannot leak into a healthy blood vessel.

Recovery Timeline for Onyx Embolization Procedure

Elective Onyx procedures require a one or two day hospital stay. If your AVM or AVF has bled, you may stay longer to recover from the bleed. Following the Onyx application you will smell a strong garlic-like odor which is caused by the metabolism of the solvent used in the Onyx system. This odor will disappear within 24-48 hours. It is common to have tenderness at the site of catheter entry, in other words, the artery near your groin. You may be asked by your care team to start moving as a little as a day or a few hours after your surgery in order to promote good blood circulation. Your own recovery will depend on your individual circumstances, but it is common to receive a prescription for pain medications and other drugs to support your care.

Why Choose Neurosurgeons of New Jersey?

Onyx embolization is an innovative and effective treatment that can prevent you from experiencing a life-threatening or debilitating brain bleed. The doctors at Neurosurgeons of New Jersey each focus on particular treatments, meaning they are experts on certain subsets of neurosurgery. Your surgeon will not only be familiar with Onyx embolization but will have chosen it as one of the few treatments he or she performs on a regular basis. When you choose Neurosurgeons of New Jersey, you will receive attention from patient-focused care teams who aim to be present and helpful throughout your treatment and recovery, both at the time of your procedure and while you are healing at home.

Our Onyx Embolization Specialists

Dr. Dorothea Altschul


Dr. Ahsan Sattar


Dr. Bree Chancellor