What are the treatment options for a brain aneurysm?

If you don't have surgery for a brain aneurysm, doctors recommend that you go for regular check-ups to see if the aneurysm has changed. If it gets bigger, for example, the risk of a rupture and bleeding in the brain increases. Then you can talk to your doctor about the possibility of preventive surgery again.

To check whether the shape or size of the aneurysm has changed, you have a type of MRI scan known as a magnetic resonance angiogram (MRA). That allows doctors to assess the risk of a rupture. To get a clearer view of the blood vessels in your brain, you may be given a contrast agent (gadolinium) through a vein in your hand or arm. This type of scan is usually done once a year. If the aneurysm doesn't change, the check-ups can often be done less frequently. But you may also need to have a CT angiogram (CTA) or a digital subtraction angiogram (DSA). In both of these examinations, you are exposed to a certain amount of radiation.

To minimize the risk of a rupture, it is also a good idea to lower high blood pressure – for example, by changing your diet and losing weight, exercising regularly or taking medication. Anyone who smokes is advised to quit.

In brain aneurysm surgery, the neurosurgeon makes a small opening in the skull: They remove a small piece of the skull bone (a few centimeters in size) and expose the affected blood vessel. They then place a small metal clip on the blood vessel to stop blood flowing into the aneurysm. That's why this approach is called “clipping.” Clipping is mainly considered as an option if the aneurysm is located in a place where it can be easily exposed and clamped off. At the end of the surgery, the removed piece of skull bone is put back and fixed in place. Once the surgery is over, patients are typically transferred to the intensive care unit for further care.

This open surgery is done under general anesthesia. To check whether the aneurysm has been closed off successfully, an angiogram is done after the surgery.

The clip stays in the body. The blood in the clipped aneurysm clots and the body turns it into connective tissue over time. The aim of clipping is to prevent bleeding in the brain.

But the surgery itself can lead to serious complications such as strokes or severe bleeding, damaging brain tissue and nerves. This may lead to paralysis, unusual sensations, vision problems or speech problems. In one scientific study, about 20 out of 100 people had these kinds of complications after their aneurysm was clipped. About 1 out of 100 people needed long-term nursing care in daily life after the operation, or died as a result of the procedure. Because the study has some weaknesses, these numbers are only rough estimates. There are also general risks associated with surgery, such as bleeding, circulatory problems or infections.

Microsurgery (clipping) puts quite a strain on your body, so it's more suitable for people who don't have any major health problems. Their bodies can handle the surgery better, and recover faster.

For this endovascular treatment ("through blood vessels"), the skull doesn't have to be opened up. Instead, a catheter (tube) is inserted into an artery in your arm or groin and guided through your bloodstream until it reaches the aneurysm. This is done under general anesthesia. The doctor can then place small platinum coils in the aneurysm through the catheter. That's why this procedure is called “coiling.” The idea is that the coils will cause the blood in the aneurysm to clot, preventing any more blood from flowing into it.

Sometimes stents or flow diverters are put in, either instead of the coils or in addition to them. These tiny tubes made of a metal wire mesh are designed either to support the coiling process or to act as a scaffold inside the blood vessel where the aneurysm is. The blood can then flow through the stent and past the aneurysm.

Once the procedure is over, an angiogram is done to check whether it was successful. You will stay in the hospital afterwards – possibly in the intensive care unit. Specialists recommend that you have check-ups for the rest of your life, usually involving MRI angiogram scans. Depending on the exact type of procedure you had, you may have to use anticoagulants (medication to prevent blood clots) for the rest of your life.

This catheter-based endovascular procedure is generally more suitable for people who can't have microsurgery because it would be too much of a strain on their body. But the catheter procedure isn't suitable for every aneurysm.

One disadvantage of this procedure is that the blood in the aneurysm might not clot completely, and then blood continues to flow into it. If that happens, you will need to have another surgical procedure. Because of this, the area where the aneurysm was located is checked regularly after a catheter procedure.

Treatment with a catheter carries risks, too: The catheter may damage the blood vessel from the inside, which can also cause bleeding, blood flow problems and brain damage. In one scientific study, about 10 out of 100 people experienced serious complications after having a coiling procedure. Around 1 out of 100 people needed long-term nursing care in daily life because of this, or died as a result. The study has some weaknesses, though, so these numbers are only rough estimates. As with any surgical procedure, complications such as wound infections or circulatory problems are also possible.