| Arteriovenous malformations are masses of | | | | allowing their removal with relative safety to the |
| abnormal blood vessels which grow in the brain. They | | | | surrounding brain. This factor is of the utmost |
| consist of a blood vessel "nidus" (nest) through which | | | | importance to the brain surgeon, who can take |
| arteries connect directly to veins, instead of through | | | | advantage of this natural separation between normal |
| the elaborate collection of very small vessels called | | | | brain tissue and the abnormal vascular malformation. |
| capillaries. Some people are born with the nidus, but | | | | TREATMENT OPTIONS |
| as the years go by, it tends to enlarge as the great | | | | Radiation |
| pressure of the arterial vessels can not be handled | | | | If there is a very small AVM, and it is deep seated in |
| by the veins that drain out of it. This causes a large | | | | the brain, the patient is fortunate. It is possible to |
| collection of worm-like vessels to develop (malform) | | | | give focused beam radiation to the malformation, and |
| into a mass capable of bleeding at some future time. | | | | avoid surgery. Within two years the malformation will |
| These malformations are most likely to bleed | | | | most likely disappear. |
| between the ages of 10 - 55; after 55, the chances | | | | Embolization |
| of bleeding diminishes rapidly. Before 55, the likelihood | | | | Larger malformations may be made more surgically |
| of hemorrhaging is betweeen 3 and 4% per year | | | | manageable with a technique called embolization. With |
| (with a death incidence of about 1%). Once an AVM | | | | this procedure an angiogram becomes a therapeutic |
| patient has hemorrhaged, the risk of having another | | | | tool. The interventional angiographer is capable of |
| one might approach 20% during the first year, and | | | | filling the malformation with agents which help |
| gradually lessen to about 3 - 4% over the next few | | | | decrease the blood supply to the malformation (coils, |
| years. | | | | glues, plastic spheres, balloons, etc). This makes |
| AVM s can occur in any area of the brain, and may | | | | surgery easier in some cases. The technique has |
| be either small or large. When they hemorrhage, they | | | | been used as the primary treatment as well, and has |
| usually do so with a limited amount of blood, unlike | | | | apparently been successful in some cases. |
| the hypertensive hemorrhages of other stroke | | | | Surgery |
| patients. Loss of neurologic function depends on both | | | | Perhaps surgery is still the best way to go if the |
| the location of the AVM and the amount of bleeding. | | | | decision has been made to do something to eliminate |
| Many patients have very small hemorrhages, often | | | | the AVM for good. Surgery cures these lesions by |
| multiple. They may display convulsions before even | | | | totally removing them, thus disallowing them from |
| knowing about the presence of an AVM. Some | | | | ever recurring again. The author's personal bias (quite |
| patients suffer with headaches, often unrelated to | | | | strongly held) is that most AVM's are best cared for |
| the AVM which are usually found with a CT scan or | | | | with surgical removal. Even with patients who have |
| brain MRI. In rare instances, children are born with | | | | large and complex AVM's, surgery provides the cure |
| large AVM's and are found to have heart failure | | | | when the malformation is completely removed. |
| because the malformation makes the heart work | | | | Today, with the assistance of BrainLab's most |
| beyond its capacity. | | | | sophisticated equipment and computerized |
| These lesions are surrounded by a very discrete | | | | techniques, an AVM removal has been greatly |
| layer of abnormal, nonfunctioning brain tissue, thus | | | | facilitated. |