Brain Arteriovenous Malformations (AVMs) Treatment
Arteriovenous malformations (AVMs) are typically diagnosed by a CT scan or MRI upon presentation of symptoms that may include seizures, headache or stroke-like episodes. Once an AVM is confirmed, an angiogram or arteriogram is performed to identify the vessels involved in the malformation. Angiography is the only test currently available that provides sufficiently detailed information useful in planning and implementing therapy of most AVMs.
There are three major treatment methods that may be useful either alone or in combination to treat an AVM. The specific treatment for an individual is based on the patient’s history, symptoms, and anatomy of the AVM including its size, feeding arteries, draining veins, and location within the brain. Treatments include: endovascular embolization (closure of the AVM from within the blood vessels), open surgical removal of the AVM, radiosurgery or a combination of techniques.
Open
surgical treatment involves removing a portion of the skull so
that surgical instruments can be inserted to remove the AVM.
Surgical treatment is often performed after embolization has
closed portions of the
AVM. The combination of embolization followed by surgical resection
is frequently safer than surgical resection alone in treating
an AVM.
Radiosurgery is a technique which uses focused beams of radiation
to treat particular AVMs that are sufficiently small and located
in appropriate areas of the brain. Despite the name, no opening
of the skull is required. Instead, the radiation causes scarring
in blood vessels of the AVM, thereby eliminating it. After treating
the AVM with radiosurgery, a period of two to three years is
required for the full effect of the treatment to be determined.
In over 80% of cases where the AVM is sufficiently small, there
is complete obliteration of the AVM.
Embolization is an endovascular technique (performed from within the blood vessels) to block the vessels of the AVM. In this procedure, a small catheter is threaded from the groin directly into the AVM vessels within the brain. Under X-ray guidance, material is injected through the catheter to permanently block and close off the vessels of the AVM. Materials used might include particles, small platinum coils, and/or liquid embolic agents similar to glue.
Embolization of an AVM is usually performed before treatment by either surgery or radiosurgery. Embolization is often able to decrease the size of the AVM making the surgery or radiosurgery much safer than would otherwise be the case. However, the blood flow from certain AVM’s may be totally blocked by embolization techniques, and no further therapy may be required.
Will all my symptoms be cured by treatment of the AVM?
Treatment of an AVM is directed toward preventing brain injury that could result from bleeding or re-bleeding. No treatment currently exists which can repair damage already done to the brain by the AVM. For example, seizures might continue after embolization or even complete removal of the AVM. Patients with neurological deficits resulting from AVM hemorrhage would likely still experience the same deficits after treatment of the AVM, although improvement may occur.