Arteriovenous Malformation

An arteriovenous malformation (AVM) is an abnormal tangle of blood vessels in the brain. Some AVMs never burst (rupture). But there are factors that can lead to rupture. Some factors are known, such as an increase in blood pressure. And some factors are not known. If you have an AVM, you were likely born with it. But most people don't know they have one until a problem happens. Signs of an AVM include bad headaches, sudden or progressive paralysis or loss of sensation, blurred or double vision, and jerking movements that are out of your control (seizures).

The brain controls the body. You can move and feel because of the brain. And it is the brain that makes you able to think, show emotions, remember, and make judgments. An AVM can damage the brain and put the rest of the body in danger.

Under the scalp and the skull, a tough membrane (called the dura) surrounds the brain. Beneath the dura, cerebrospinal fluid (CSF) cushions the brain. Blood vessels carry nutrients and oxygen-rich blood throughout the brain.

An AVM is a tangle of blood vessels. It can cause pressure to build up in the blood vessel and prevent normal blood flow. If the pressure becomes too great or the wall of the AVM vessel weakens a blood vessel can burst and blood can leak or spurt into the brain. This can damage parts of the brain that control vital body functions, such as sight, sensation, language, critical thinking, and movements. In some cases, problems caused by an AVM can even lead to death. The high blood flow in an AVM can also shunt the oxygen from the arteries directly to veins, bypassing the brain capillaries. This shunting can lead to strokes. But an AVM can be treated.

It's important to get medical attention for an AVM as soon as possible. Often, immediate treatment may help prevent serious complications of some AVMs. Current surgical methods make treatment for AVM safer and more effective than ever. The goal of treatment is to stop the flow of blood within the AVM and to prevent it from re-bleeding.

The members of your healthcare team guide you through your treatment, support you, and answer your questions. Your team may include the following specialists:

• A neurosurgeon. This healthcare provider does the procedure needed to correct your problem.
• A radiologist. This healthcare provider specializes in using radiation in the diagnosis and treatment of disease.
• A neurologist. This specialist helps co-manage the person during the acute phase of illness, helps direct recovery therapy, and helps manage complications such as seizures.
• Nurses. These professionals provide patient care and may also teach family and friends to help with your recovery.
• Physiatrists. These healthcare providers specialize in rehabilitation. They help direct the recovery of lost motor and language skills.
• Physical and occupational therapists. These providers help with walking, dressing, and other life skills.
• Speech therapists. These providers focus on speech and swallowing problems.
• A case manager or social worker.  These professionals help guide you through the healthcare system.

Surgical resection removes the tangled blood vessels.

• Reaching the brain. The surgeon uses a procedure called craniotomy to reach the brain. During a craniotomy, small holes called burr holes are made in the skull. The bone between the holes is cut and lifted away. Finally, the surgeon opens the dura and exposes the brain.
• Removing the AVM. Once the surgeon has access to the AVM, the abnormal arteries and veins are removed. This redirects blood flow to normal vessels, preventing the AVM from bursting and leaking blood.
• Closing the skull. When the AVM has been removed, the dura covering the brain is closed. In most cases, the skull bone is put back. The skull bone can be held in place using one of several methods. Titanium clamps are often used, as they provide the most stability and cover the burr holes. After the clamps are in place, the skin incision is closed with stitches or staples.

AVMs sometimes require a combination of treatments. Other treatments include:

• Radiosurgery. Radiation (beams of gamma rays) can be directed at the AVM using tools called gamma knife, LINAC, or proton beam. The irradiation delivered by the gamma knife closes off the abnormal blood vessels, so that blood no longer flows through them. Specialists (neurosurgeon, physicist, and radiation oncologist with special training in this field) will be involved.
• Embolization. Glue is inserted into the AVM through a catheter (very thin tube). This blocks blood flow in the AVM and holds the blood vessels in a new location. Embolization may happen by itself or as part of the surgical procedure. Beads, tiny balloons, or coils (tiny, spring-shaped objects) can also be used to embolize an AVM. A specialist will be involved in embolization.