What Are AVMs?

Arteriovenous Malformation & Cancer Treatment in Orange County, CA

At Orange County CyberKnife, we’re proud to provide world-class radiation therapy using some of the most advanced cancer fighting systems on the market today. Our team of doctors, radiation oncologists, and cancer fighting specialists includes leaders in the cancer treatment field, and we strive to take a personalized approach to caring for patients, designing personalized treatment plans and using compassion to make the cancer treatment process easier. While we specialize in the CyberKnife cancer treatment system, we can also treat a variety of other conditions – including arteriovenous malformations (AVMs).

About Arteriovenous Malformations

Arteriovenous malformations occur when different blood vessels tangle together, forming irregular, unhealthy connections between arteries and veins. Arteries and veins from two similar, but very distinct, functions: arteries carry oxygen-rich blood to the cells, while veins carry oxygen-depleted blood back to the lungs. Normally, blood passes from an artery through a system of capillaries – tiny, microscopic vessels where oxygen is transmitted from blood cells to tissue – then out of the capillaries into a vein. In an AVM, the capillary system is compromised, forming direct connections between an artery and a vein. If the AVM is large enough, it can rob surrounding tissue of oxygen, eventually leading to tissue damage, the death of nerve cells, and potentially more serious consequences.

Scientists aren’t sure why AVMs form, but most evidence points to congenital factors. While AVMs can develop anywhere in the body, they’re most common in the brain and the spinal cord. While many AVMs start small and relatively inconsequential, they can expand in size over time, eventually causing serious problems for the patient.

Symptoms of AVMs

Symptoms of an AVM can be extremely diverse, and they’re very dependent on where the AVM forms and how large it gets. While some AVMs produce only minor irritation, in some cases they can be life threatening. For AVMs in the brain, seizures and headaches are two of the most common symptoms.

Seizures from AVMs may affect only a specific part of the brain (focal) or they may affect the entire brain (widespread), potentially causing the person to lose control of their body and experience convulsions. Headaches may be mild or as severe as a migraine, and there’s no clear pattern in frequency, length, or intensity. Other AVM symptoms include:

  • Weak muscles or partial paralysis
  • Lack of coordination (ataxia) that may interfere with how a person walks
  • Difficulty with planning and executive function
  • In the case of a spinal AVM, back pain or pain in the lower parts of the body is common
  • Dizziness
  • Partial loss of vision, inability to control the eye, or a swollen optic nerve
  • Inability to understand language or difficulty speaking (aphasia)
  • Spontaneous and inexplicable pain, numbness, or other sensations
  • Problems with memory
  • Hallucinations, dementia, or general confusion
  • In some cases, an AVM can cause learning disabilities or behavioral disorders in childhood before other symptoms develop

Neurological AVMs

Neurological AVMs refer to AVMs that form in the brain or the spinal cord. These AVMs are particularly problematic, as they’re the most likely to impair motor function, cause seizures and headaches, and create other debilitating side effects. Neurological AVMs may prevent the brain from getting enough oxygen, cause bleeding in the brain or spinal cord, or compress or displace parts of the brain or spinal cord. Neurological AVMs may form anywhere in the brain or spinal cord where arteries and veins of present, causing a number of different problems depending on their location. AVMs may form in the tissues of the brain or in the surrounding membranes.

AVMs in the Spinal Cord

When formed in the spinal cord, AVMs may have a number of symptoms ranging from severe, sudden back pain similar to that from a slipped disk. Other symptoms can include problems with the senses, weak muscles, or even paralysis in certain areas of the body. This is because an AVMs in the spinal cord can cause the nerve fibers below it to degrade and eventually to die, which can impede communication with parts of the body those nerve fibers control or leave those areas paralyzed entirely.

AVMs in the Brain

AVMs may form at various locations in the brain, and their symptoms will differ based on where the form. AVMs formed in the outermost parts of the brain can push on the brain, potentially causing headaches and other problems. If an AVM forms in the brain, it may have a host of symptoms depending on its location. AVMs in the brain can impair motor function, language, sensory input, vision, or thinking. If an AVM forms deep in the cerebrum, it may cause even more severe problems in movement, learning, or memory. If an AVM forms in the hindbrain, which is responsible for basic vital functions, balance, and many movements, it may cause a variety of problems. Potential symptoms include giddiness, dizziness, vomiting, loss of coordination, or muscle tremors.

Are AVMs Fatal?

The most severe problem an AVM can cause is a hemorrhage, where the AVM begins to bleed into surrounding tissue. Often, such episodes of bleeding go undetected because they’re not severe enough to seriously damage the brain, but if the hemorrhage is large enough, it may be fatal. There are a number of factors that affect the risk of hemorrhage from an AVM:

  • Smaller AVMs are more likely to bleed than larger ones
  • Hemorrhage is more common in AVMs occurring in deep or narrow veins with less drainage
  • Pregnancy increases the likelihood of serious hemorrhage
  • If an AVM hemorrhages once, it’s 9 times more likely to bleed again within one year compared to an AVM that has never bled

Contact Your Orange County, CA Cancer Treatment Center

While some AVMs are mild enough to be virtually undetectable, others may cause severe, debilitating, or life-threatening consequences – but at Orange County CyberKnife, we’re here to help. We’re proud to treat patients for wide variety of conditions at our Orange County cancer treatment center, and if you or someone you know has recently been diagnosed with an AVM or a cancerous condition, we are committed to providing world-class treatment. If you’d like to find out more about how we can help you overcome whatever you’re facing, please call us today at 714.962.7100 with any questions or reach out to us at our contact page to schedule an appointment. Fighting cancer or an AVM can be a scary, difficult process – but the team at Orange County CyberKnife is committed to helping you reclaim total health.

AVM Treatment Options

Arteriovenous malformations (AVMs) are abnormal, snarled tangles of blood vessels that cause multiple irregular connections between the arteries and veins. While they are most common in the spinal cord and the brain, they can develop elsewhere in the body. It is unclear why AVMs form. Most often they are inherited, but they can sometimes appear sporadically. ATMs can cause seizures and severe headaches as well as muscle weakness, paralysis, dizziness, vision loss, back pain, confusion, and more. Most dangerously, AVMs can cause significant neurological damage and brain hemorrhaging. Orange County CyberKnife and Radiation Oncology Center offers the most comprehensive array of radiation treatments in Southern California including the CyberKnife Radiosurgery System, an effective treatment for AVMs.

How are AVMs and other vascular lesions treated?

There are several treatment options for patients with AVM, but each involves various dangers depending on the individual. A hemorrhage from an untreated AVM can cause serious neurological damage or death, leading many specialists to recommend surgery. However, surgery on any part of the central nervous system carries risk of serious complications or death. An AVM grading system developed in the mid-80s can help healthcare professionals estimate the risk of surgery based on the size of the AVM, location in the brain and surrounding tissue involvement, and any leakage. Treatment options include:

  • Medication. Although medicines can often lessen general symptoms, such as headache, back pain, and seizures, the definitive treatment for AVMs is either surgery or focused radiation therapy.
  • Conventional surgery – Surgery involves entering the brain or spinal cord and removing the central portion of the AVM, including the fistula. This surgery is most recommended when an AVM is located in a superficial portion of the brain or spinal cord and is relatively small in size. AVMs located deep inside the brain generally cannot be approached through conventional surgical techniques because there is too great a possibility that functionally important brain tissue will be damaged or destroyed.
  • Endovascular embolization – For this treatment, a surgeon guides a catheter through the arterial network until the tip reaches the site of the AVM, then injects a fast-drying glue-like substance, fibered titanium coils or a tiny balloon) that will travel through blood vessels and create an artificial blood clot in the center of an AVM. Since embolization usually does not permanently obliterate the AVM, it is usually used in conjunction with surgery or to radiosurgery to reduce the blood flow through the AVM and make the surgery safer.
  • CyberKnife Radiosurgery – A non-invasive therapeutic approach often used to treat small AVMs that haven’t ruptured is radiosurgery, in which a beam of highly focused radiation is aimed directly on the AVM and damages the walls of the blood vessels making up the lesion. Orange County CyberKnife utilizes the newest technology in radiosurgery – the CyberKnife Radiosurgery System – to effectively treat AVMs. CyberKnife combines a flexible robotic arm with state-of-the-art imaging system to pinpoint the exact location of the AVM minimizing damage to surrounding tissue or organs. The flexibility allows CyberKnife to reach AVMs at hundreds of different angles. Over the course of the next several months, the irradiated vessels gradually degenerate and eventually close, leading to the resolution of the AVM.

Find Out More About CyberKnife Treatment of AVMs

If you want to learn more about the CyberKnife Radiosurgery System at Orange County CyberKnife and how it can treat your AVM, reach out to our medical oncology experts by phone at (714) 962-7100 or by completing our convenient online appointment form. Our cancer specialists are ready to answer all of your questions in detail and your first phone consultation is free. You can trust the specialists at Orange County to provide individualized treatment for your AVM. Call today.

AVM: Types & Stages

Are there different types of brain AVMs?

All blood vessel malformations involving the brain and its surrounding structures are commonly referred to as AVMs. But several types exist:

  • True arteriovenous malformation (AVM).This is the most common brain vascular malformation. It consists of a tangle of abnormal vessels connecting arteries and veins with no normal intervening brain tissue.
  • Occult or cryptic AVM or cavernous malformations.This is a vascular malformation in the brain that doesn’t actively divert large amounts of blood. It may bleed and often produce seizures.
  • Venous malformation.This is an abnormality only of the veins. The veins are either enlarged or appear in abnormal locations within the brain.
  • Hemangioma.These are abnormal blood vessel structures usually found at the surface of the brain and on the skin or facial structures. These represent large and abnormal pockets of blood within normal tissue planes of the body.
  • Dural fistula.The covering of the brain is called the “dura mater.” An abnormal connection between blood vessels that involve only this covering is called a dural fistula. Dural fistulas can occur in any part of the brain covering. Three kinds of dural fistulas are:
  • Dural carotid cavernous sinus fistula.These occur behind the eye and usually cause symptoms because they divert too much blood toward the eye. Patients have eye swelling, decreased vision, redness and congestion of the eye. They often can hear a “swishing” noise.
  • Transverse­Sigmoid sinus dural fistula.These occur behind the ear. Patients usually complain of hearing a continuous noise (bruit) that occurs with each heartbeat, local pain behind the ear, headaches and neck pain.
  • Sagittal sinus and scalp dural fistula.These occur toward the top of the head. Patients complain of noise (bruit), headaches, and pain near the top of the head; they may have prominent blood vessels on the scalp and above the ear

Physicians do not categorize states of arteriovenous malformation (AVM) as it is not a progressive disease. The condition is congenital – occurring at birth – and continues through life unless treated. In many cases, symptoms never appear and the person leads a normal life unaware of the condition. However, an AVM can grow, creating pressure on surrounding areas of the brain, leading to headaches, dizziness and confusion. In addition, the AVM can reach a stage of development where it may burst.


Answer :

Brain AVMs occur in less than 1 percent of the general population. It’s estimated that about one in 200–500 people may have an AVM. AVMs are more common in males than in females.

Answer :

We don’t know why AVMs occur. Brain AVMs are usually congenital, meaning someone is born with one. But they’re usually not hereditary. People probably don’t inherit an AVM from their parents, and they probably won’t pass one on
to their children.

Answer :

Brain AVMs can occur anywhere within the brain or on its covering. This includes the four major lobes of the front part of the brain (frontal, parietal, temporal, occipital), the back part of the brain (cerebellum), the brainstem, or the ventricles (deep spaces within the brain that produce and circulate the cerebrospinal fluid).

Answer :

Most AVMs don’t grow or change much, although the vessels involved may dilate (widen). Some AVMs may shrink due to clots in part of the AVM. Some may enlarge to redirect blood in adjacent vessels toward an AVM.

Answer :

A brain AVM contains abnormal and, therefore, “weakened” blood vessels that direct blood away from normal brain tissue. These abnormal and weak blood vessels dilate over time. Eventually they may burst from the high pressure of blood flow from the arteries, causing bleeding into the brain.

Answer :

The chance of a brain AVM bleeding is 1 percent to 3 percent per year. Over 15 years, the total chance of an AVM bleeding into the brain — causing brain damage and stroke — is 25 percent.

Answer :

The risk of recurrent intracranial bleeding is slightly higher for a short time after the first bleed. In two studies, the risk during the first year after initial bleeding was 6 percent and then dropped to the baseline rate. In another study, the risk of recurrence during the first year was 17.9 percent. The risk of recurrent bleeding may be even higher in the first year after the second bleed and has been reported to be 25 percent during that year. People who are between 11 to 35 years old and who have an AVM are at a slightly higher risk of bleeding.

Answer :

The risk of death related to each bleed is 10 percent to 15 percent. The chance of permanent brain damage is 20 percent to 30 percent. Each time blood leaks into the brain, normal brain tissue is damaged. This results in loss of normal function, which may be temporary or permanent. Some possible symptoms include arm or leg weakness/paralysis, or difficulty with speech, vision or memory. The amount of brain damage depends on how much blood has leaked from the AVM.