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Brain aneurysms can be treated using surgery if they have burst (ruptured) or there's a risk they will.

Preventative surgery is usually only recommended if there's a high risk of a rupture.

This is because surgery has its own risk of potentially serious complications, such as brain damage or stroke.

If you're 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 the risks associated with surgery in older adults often outweigh the potential benefits (extending natural lifespan)
  • 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 rupture
  • family history – brain aneurysms are considered to have 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 case.

If the risk of rupture is considered low, a policy of active observation is normally recommended.

This means you won't receive immediate surgery, but you'll be given regular check-ups so your aneurysm can be carefully monitored.

You may also be given medication to lower your blood pressure.

Your doctor will discuss lifestyle changes that can help lower the risk of a rupture, such as losing weight and reducing the amount of fat in your diet.

If preventative treatment is recommended, the 2 main techniques used are called neurosurgical clipping and endovascular coiling.

Both techniques help prevent ruptures by stopping blood flowing into the aneurysm.

Neurosurgical clipping

Neurosurgical clipping is carried out under general anaesthetic, so you'll be asleep throughout the operation.

A cut is made in your scalp, or sometimes just above your eyebrow, and a small flap of bone is removed so the surgeon can access your brain.

When the aneurysm is located, the neurosurgeon 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 growing or rupturing in the future.

Clipping the artery the aneurysm is formed on, 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's 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

Endovascular coiling is also usually carried out under 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, up 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 growing or rupturing.

Whether clipping or coiling is used often depends on 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 risks and benefits of both procedures.

Coiling has generally been shown to have a lower risk of complications, such as seizures, than clipping in the short term, although the benefits in the long term aren't certain.

With coiling, there's also a small chance you'll need to have the procedure more than once to reduce your chances of the aneurysm rupturing.

About 1 in 5 people who have the coiling procedure need further treatment.

But as coiling is a less invasive procedure, you can usually leave hospital sooner after the operation.

After clipping, you'll usually need to stay in hospital for around 4 to 6 days, whereas you can usually go home 1 or 2 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 may take longer.

If you require emergency treatment because of a ruptured brain aneurysm, you'll 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 like your recovery time and hospital stay depend more on the severity of the rupture than the type of surgery carried out.