Arteriovenous malformations are abnormal blood vessels in the brain, and are a dangerous medical condition because, if they bleed, they can cause significant neurological damage or even death.
One treatment for arteriovenous malformations include exposing the abnormal blood vessel (aneurysm) by performing a craniotomy and closing the base of it with a clip. This is called surgical clipping. The advantage of surgical clipping is that, if it is successful, the patient is at no risk for bleeding the day after the surgical procedure. However, it is an invasive procedure requiring a hospital say, and carries the risk of infection, bleeding, permanent neurological damage, and an adverse reaction from the anesthesia. In addition, the arteriovenous malformation is often too deep in the brain for surgical clipping.
Gamma knife radiosurgery is also a well-recognized treatment for arteriovenous malformations. The patient is not at risk for invasive surgical complications, and the hospital stay is reduced. However, if the arteriovenous malformation is not completely obliterated by the gamma knife, the patient has a risk of bleeding. The complete obliteration of arteriovenous malformation can take up to two years after gamma knife radiosurgery.