Cerebrovascular Disease

What is a Cerebral Aneurysm?

Aneurysms are weak spots in the walls of arteries that balloon out over the course of years. These balloons have walls that are thinned out enough that they can rupture, causing severe bleeding in or around the brain.

What causes them?

No one knows why the majority people who have cerebral aneurysms get them. About 2% of the American population has of these aneurysms. Certain conditions may predispose you to develop cerebral aneurysms such as polycystic kidneys, systemic lupus erythematosus, or Erhlers Danlos syndrome. For the most part, a ruptured aneurysms can only be ascribed to bad luck, and only very occasionally do aneurysms run in families.

How do I know if I have one?

Cerebral aneurysms cause problems in two general ways. The first and most life threatening is bleeding. This results in the rapid onset of a severe headache (the worst headache of my life) associated with transient loss of consciousness. The headache is usually followed by neck stiffness, back pain, nausea or vomiting, and an inability to tolerate bright light. This situation constitutes an emergency, and immediate medical care must be sought. The second (much less common) way aneurysms cause problems is if they reach such a large size that they cause pressure on the brain or nerves. This situation may cause a seizure, double vision, progressive blindness in one eye, or numbness on one side of the face.

Unfortunately, unless aneurysms cause one of the above mentioned problems, there is no way to know that you have one. Occasionally they are discovered "accidentally" when a CAT scan or MRI scan is performed for other reasons. Cerebral aneurysms are truly silent killers.

What happens when an aneurysms ruptures?

The bleeding that occurs inside the head when an aneurysm bursts can cause severe brain damage or even death. Over 40% of people will die within the first few days after a hemorrhage, of the remaining 60% less than half will ever return to their normal activities. For the lucky ones who survive the first hemorrhage, several important considerations must be met. First, steps must be taken to make sure the aneurysm does not burst again. If it does there is a 70% chance of death. Second, brain damage from pressure inside the head must be avoided. Third, treatment must be given to avoid cerebral vasospasm, a condition that can cause stroke or further brain damage one to two weeks after the aneurysms bursts.

They think they found an aneurysm on my CAT scan or MRI scan.

What is the next step?

In order to determine for sure if you have an aneurysm, an angiogram (arteriogram) must be performed. With local anesthesia, in the hospital, a catheter is placed in a leg artery and passed into the arteries leading to the brain. Dye is injected and multiple X-rays are taken of the brain. Only with this test, which has a small amount of risk, can your surgeon determine the location, size and risk of your aneurysm.

They found my aneurysm before it burst.

How should I proceed?

Not all aneurysms will rupture. A ballpark figure is 2% chance per year from the time of discovery. So if one is found at age 50, theoretically there is a 50% chance that the aneurysm will burst by age 75 years. However, larger aneurysms and those on the vertebral-basilar circulation may be more dangerous. A frank discussion with your surgeon will help you balance the risks and benefits of treating the aneurysm.

What can be done about cerebral aneurysms?

The most successful form of therapy is a surgical procedure that places a clip across the base of the aneurysm so it no longer fills with blood. This is a technically demanding but highly successful procedure done through an operating microscope using state-of-the-art instrumentation. The Neurovascular Division of USC's Department of Neurological Surgery has successfully managed over 1000 of these cases, more than any team in California.

When clip ligation is not possible, other techniques have been and continue to be developed at USC to deal with special cases. Many aneurysms are now being treated by packing them full of soft platinum coils. This technique is performed through a catheter inserted through an artery in the groin. It has the obvious benefit of avoiding a craniotomy. As experience with this technique grows, more cerebral aneurysms are able to be treated this way. For those aneurysms with even greater complexity, a number of techniques and medical disciplines can be summoned in order to obliterate these lesions in a safe and effective manner. Those techniques include balloon test occlusion, neurophysiologic monitoring, bypass grafting the affected artery, reconstructing the affected artery, and the use of hypothermic cardiac arrest. Because the techniques and personnel needed to deal with these multi-disciplinary and complex conditions reside in one department (USC Department of Neurological Surgery), decision making regarding the best course of action for each individual case is facilitated.

What are the risks of surgery?

This depends on a number of factors including pre-existing brain damage, age and health of the patient, location and size of the aneurysm and whether or not the aneurysm has ruptured. Because of the experience of USC's team, success rate for certain types of aneurysms is 95% or greater. Only teams that specialize in this type of surgery can be expected to attain such results.

Is it a difficult decision?

Yes, it is. It is possible that your surgeon can give you names of people who have made a similar decision, and who would be willing to talk to you regarding your treatment.

For further information or to schedule an appointment please contact the Neurosurgery Clinical Office at (323) 442-5720

The $50,000 Haircut: The true story of one man's struggle and triumph over an unruptured aneurysm.