Brain AVMs

What is a brain AVM?

A brain arteriovenous malformation (AVM) is an abnormal tangle of blood vessels in the brain. It involves a direct connection between arteries and veins, bypassing the normal capillary system. This can disrupt normal blood flow and oxygen delivery to surrounding brain tissue. It also increases the risk of bleeding in the brain from rupture of one of these abnormal blood vessels.

What causes a brain AVM?

The exact cause of brain AVMs is not fully understood. They are believed to develop before birth but usually do not cause symptoms until later in life. Only around 2% of brain AVMs are hereditary, linked to rare conditions like hereditary hemorrhagic telangiectasia (HHT).

What symptoms can a brain AVM produce?

Many brain AVMs are asymptomatic, but when symptoms occur, they may include:

Headaches.
Seizures.
Neurological deficits, such as weakness, numbness, or vision changes.
Intracranial hemorrhage (bleeding in the brain) if the AVM ruptures, which can be life-threatening.

How is a brain AVM diagnosed?

Brain AVMs are often diagnosed using imaging studies such as:

CT Scan or MRI to detect structural abnormalities.
Cerebral Angiogram to map the AVM's structure in detail.

How are brain AVMs classified?

The Spetzler-Martin grading system is a tool used to assess brain arteriovenous malformations (AVMs) and guide treatment decisions. It grades AVMs based on their characteristics and the risks associated with surgical removal. This system helps neurosurgeons predict the difficulty and potential complications of surgery.

The Spetzler-Martin grading system assigns a grade from 1 to 5, based on three factors – size, location, and the pattern of venous drainage. It is a useful tool, but treatment decisions depend on this and a variety of other factors, including a patient’s age, overall health, symptoms, and the experience of the surgical team. The Spetzler-Martin grade is often used in conjunction with other assessments to develop an individualised treatment plan.

How is a brain AVM treated?

Untreated AVMs pose a risk of rupture, which can cause bleeding in the brain, stroke, or permanent neurological damage. Treatment depends on the AVM's size, location, and risk of complications.

Options include:

Observation: Including monitoring with MRI scans.
Surgical Resection: Removal of the AVM through open brain surgery.
Endovascular Embolisation: Minimally invasive procedure, performed via an angiogram, to block the abnormal vessels from the inside.
Stereotactic Radiosurgery: (including Gamma Knife Radiosurgery). Focused radiation to shrink and close the AVM over time.

For more information on the treatment options for brain AVM, click on the links in the list above.

📌 Important note: This website provides general information only. Your specialist team will discuss your individual situation, risks, and treatment plan with you.