Arteriovenous malformations (AVM) of the brain are a tangle of abnormal blood vessels in which high pressure arterial blood is shunted into veins without intervening capillary bed. While these are thought to be congenital in origin, it is possible that in some people they are acquired over time. Many patients with AVM’s have no symptoms until they bleed into or around the brain. Other patients report headaches or seizures as possible symptoms of the AVM.
Treatment of AVM’s depend on location, size, symptoms, patient’s age and general medical state. For AVM’s located deep in the brain or in critical areas that are small and have bled, Gamma Knife treatment may be quite helpful. For AVM’s that have not bled, recent studies cast doubt about whether or not any treatment is warranted, but individualized decisions need to be made with patients and physicians knowledgeable in treating these abnormalities. Large AVM’s may require staged radiosurgery to treat.
When Gamma Knife treatment is given for AVM’s, it is important to understand that the goal of treatment is to prevent future bleeding. This goal is not achieved immediately—it often takes two to three years to see obliteration of the abnormal blood vessels. If, after 3 years, residual AVM is present, another treatment may be helpful.