An Arteriovenous Malformation or AVM is an abnormal tangle of blood vessel connecting an artery to a vein. An AVM can develop anywhere in the body but occurs most often in the brain or spine. The causes of AVM are unknown but most brain AVMs are congenital which means someone is born with one. The feeding artery of an AVM directs blood away from the normal brain tissue causing symptoms which may include headache, seizures, weakness or numbness, difficulty speaking, confusion, vision loss. In extreme cases, the blood vessel forming AVM, may burst from the high pressure of blood flow which can cause bleeding in the brain, a condition called hemorrhagic stroke. Please read more in the AVM chapter.
The treatment options for AVM aim to reduce the blood flow to the feeding artery of AVM thus reducing the risk of bleeding from AVM. The treatment options include surgical removal or endovascular embolization of AVM. The endovascular embolization of AVM is a minimally invasive procedure in which endovascular surgeon or neuro-interventionalist makes a small incision in the groin and passes a navigating tube from the femoral artery. The tube is then advanced up in one of the artery forming AVM and an embolizing agent such as glue like substance or micro coils are injected to block the blood supply to AVM. (see figure): In some cases, AVM embolization is done before its removal by open surgery to reduce its size or the likelihood of bleeding. (see figure):
Please see section of neurosurgical procedures for information on open surgical treatment of brain and spine AVM.
Figure : Cerebral angiogram showing AVM embolization (A) Before embolization (B) Complete obliteration of AVM after embolization
Figure : Surgically resected AVM