Brain aneurysms can be treated using surgery if they have burst (ruptured) or if there is a risk that they will.
However, preventative surgery is usually only recommended if it's thought the risk of a rupture is significant. This is because surgery has it's own risk of potentially serious complications, such as brain damage or stroke.
Assessing your risk
If you are diagnosed with an unruptured brain aneurysm, a risk assessment will be carried out to assess whether surgery is necessary.
The assessment process is usually based on the following factors:
your age - research has found that in older adults, potential benefit of surgery in terms of extending natural lifespan is often outweighed by the risks associated with surgery
the size of the aneurysm - aneurysms larger than 7mm often require surgical treatment, as do aneurysms larger than 3mm in cases where there are other risk factors
the location of the aneurysm - brain aneurysms located on larger blood vessels have a higher risk of a rupture
family history - brain aneurysms are considered to be at a higher risk of rupturing if you have a history of ruptured brain aneurysm in your family
underlying health conditions - some health conditions increase the risk of a rupture, such as autosomal dominant polycystic kidney disease (ADPKD) or poorly controlled high blood pressure
After these factors have been taken into consideration, your surgical team should be able to tell you whether the benefits of surgery outweigh the potential risks in your individual case.
If the risk of rupture is considered low then a policy of active observation is normally recommended. This means you won't receive immediate surgery, but be given regular check-ups so your aneurysm can be carefully monitored.
You may also be given medication to lower your blood pressure and your doctor may discuss lifestyle changes that can help reduce the risk of a rupture, such as losing weight and reducing the amount of fat in your diet.
Surgery and procedures
If preventative treatment is recommended, the two main techniques used are called neurosurgical clipping and endovascular coiling.
Both techniques help prevent ruptures by stopping blood from flowing into the aneurysm.
Neurosurgical clipping is carried out under general anaesthetic, so you will be asleep throughout the operation. A cut is made in your scalp (or sometimes just above your eyebrow) and a small flap of bone removed so the surgeon can access your brain.
When the aneurysm is located, the neurosurgeon (an expert in surgery of the brain and nervous system) will seal it shut using a tiny metal clip that stays permanently clamped on the aneurysm. After the bone flap has been replaced, the scalp is stitched together.
Over time, the blood vessel lining will heal along the line where the clip is placed, permanently sealing the aneurysm and preventing it from growing or rupturing in the future.
Clipping the artery on which the aneurysm formed - as opposed to clipping the aneurysm itself - is rarely necessary. This is usually only carried out if the aneurysm is particularly large or complex.
When this is necessary, it is often combined with a procedure called a bypass. This is where the blood flow is diverted around the clamped area using a blood vessel removed from another place in the body (usually the leg).
Endovascular coiling is also usually carried out using general anaesthetic. The procedure involves inserting a thin tube called a catheter into an artery in your leg or groin. The tube is guided through the network of blood vessels into your head and finally into the aneurysm.
Tiny platinum coils are then passed through the tube into the aneurysm. Once the aneurysm is full of coils, blood cannot enter it. This means the aneurysm is sealed off from the main artery, which prevents it from growing or rupturing.
Coiling versus clipping
Whether clipping or coiling is used will often depend on things such as the size, location and shape of the aneurysm. Talk to your healthcare team about your treatment options.
If it's possible to have either procedure, you should discuss the benefits and risks of coiling and clipping with your care team.
Coiling has generally been shown to have a lower risk of complications (such as seizures) than clipping in the short-term, although the benefits over clipping in the long-term are not certain.
With coiling, there is also a small chance you will need to have the procedure more than once to best reduce your chances of the aneurysm rupturing. About 1 in 5 people who have the coiling procedure will need further treatment.
However, as coiling is a less invasive procedure, you can usually leave hospital sooner after the operation than with clipping. After clipping you will usually need to stay in hospital for around four to six days, whereas you can usually go home one or two days after coiling.
The time it takes to fully recover is also typically shorter with coiling. Many people make a recovery within a few weeks of coiling, whereas recovering from clipping can take several weeks or months.
If you require emergency treatment because of a ruptured brain aneurysm, you will initially be given a medication called nimodipine to reduce the risk of the blood supply to the brain becoming severely disrupted (cerebral ischaemia).
Either coiling or clipping can then be used to repair the ruptured brain aneurysm. The technique used will usually be determined by the expertise and experience of the surgeons available.
In such emergency cases, the differences between the techniques are less important because things such as your recovery time and hospital stay depend more on the severity of the rupture than the type of surgery carried out.