Arteriovenous Malformations

  • An arteriovenous malformation (AVM) is an abnormal connection between arteries and veins of the brain.
  • This is a condition that is usually present from birth and may cause headache, seizure, or bleeding into the brain (hemorrhage).
  • The treatment of AVMs can include surgery, radiosurgery, or embolization.

Arteriovenous Malformations (AVMs) are a relatively infrequent condition in which there is an abnormal connection between arteries that normally supply brain tissue and veins. This usually appears as an abnormal tangle of blood vessels and causes abnormal high flow through the lesion. AVM's can occur either in the brain or the spine and are generally present from birth. Brain AVMs may cause symptoms of headache, seizure, or rupture while spinal AVM's can cause weakness, paralysis, or loss of bowel and bladder function. Rupture of an AVM is the most serious problem and results in bleeding in the brain (intracranial hemorrhage) or spinal cord. Overall there is approximately a 2-4% annual risk of rupture for patients with previously unruptured brain AVMs.

AVMs are most commonly treated either by brain surgery or radiosurgery. Radiosurgery is a method that uses directed radiation on the abnormal vessels to cause them to shrink. This method is most effective for smaller AVMs. Embolization is a method of treating AVMs by placing tiny catheters upstream of the AVM and injecting materials under x-ray guidance to block the abnormal vessels. These materials can include coils or liquid adhesives and can cause significant reduction of the AVM size. Embolization prior to surgery can decrease blood loss and time required for surgical removal of the AVM. Embolization prior to radiosurgery can increase the likelihood that the AVM will resolve following radiation therapy.