Aneurysm

Definition

A brain aneurysm is a bulging vessel in the brain. It must be treated surgically because otherwise it may cause bleeding. Cerebral aneurysms are closed either by clipping or by coiling. Malformations in the blood vessels of the brain can lead to heavy bleeding. Cerebral aneurysm is a much-feared cause. This involves a bulging vessel in a cerebral artery and often even at a branch of the larger arteries.

A cerebral aneurysm is generally asymptomatic (presents no symptoms) until it bursts. It is therefore often only discovered when there is a brain haemorrhage. Occasionally, the aneurysm is detected by chance during a brain MRI scan. Two procedures are used for surgical treatment: clipping and coiling. Which procedure is used depends mainly on the form and size of the aneurysm. The most common, sack-shaped aneurysms are mainly treated with the endovascular (within the vessel) coiling procedure. A clipping operation is used for more complex forms of aneurysm.

Causes

There are three main types of aneurysm:

Aneurysma verum, true aneurysm

Aneurysma verum is the most common form. It involves a bulge in all three layers of the wall of the artery at a specific place (looks like a bubble blown with gum).

Causes:

·         Congenital damage to the vessel wall

·         Damage to the vessel wall due to arteriosclerosis

·         More rarely, infectious diseases (e.g. syphilis).

Aneurysma spurium, false aneurysm

False aneurysms are less about dilation and instead involve blood leakage after injury to the vessel wall. The vessel damage is patched by coagulated (clotted) blood. The resulting plug then looks like an aneurysm and stops the bleeding in most cases. False aneurysms can appear as complications after operations or after punctures to arteries.

Aneurysma dissecans

This involves a tear in the innermost layer of the vessel wall. Because of the high blood pressure in the aorta, the blood seeps further into the artery wall (dissecans = cutting). High blood pressure is a major risk factor.

Other risk factors that may favour formation of an aneurysm are:

·         Being overweight

·         Nicotine addiction

·         Diabetes

·         High blood lipid values

·         Lack of exercise

·         Lipid metabolism disorder

·         Gout

·         Old age

·         Mental or physical stress

Symptoms

Aneurysms generally develop asymptomatically and are discovered by chance during an investigation or when they tear and bleed. The first symptoms may be a vague feeling of pressure or a foreign body at the site of the aneurysm. According to the localisation and size of the aneurysm, there may be various symptoms resulting mainly from the pressure on nearby organs.

For brain aneurysms 

·         Facial paralysis

·         Stroke or brain haemorrhage when the aneurysm bursts

The dangerousness of the aneurysm depends on the size of the dilation; if the aneurysm bursts, it can lead to life-threatening bleeding. The bigger the aneurysm, the greater the danger of it bursting.

Diagnosis (tests)

Aneurysms are often discovered by chance or because of neurological abnormalities (e.g. paralysis). 

·         Medical history, taking symptoms into account

·         Physical examination

·         Ultrasound

·         Computed tomography

·         X-ray with imaging agents (angiography)

Treatment

Aneurysm clipping

With clipping, the bulge is closed with a clip and thereby separated from blood circulation.

What preparations are involved?

Before the procedure, the exact situation and the degree of dilation of the aneurysm are established using CT, MRI and angiography.

The usual tests before an operation are also carried out (ECG, blood-pressure reading and blood tests). Any blood-thinners must be stopped. Hospital admission is generally the day before the operation, except for emergencies. The operation should be done on an empty stomach.

How is the operation carried out?

Clipping of an aneurysm is performed under full anaesthetic. Through a cut in the skin, the cranium is opened in a very targeted way. An operating microscope is used for the microsurgical procedure. This enables excellent spotlighting and enlargement of the operation area. Thanks to the microscope, even the smallest structures can be identified and the operation carried out carefully. The aneurysm is sealed from outside using one or more clips and the danger of rupture is averted. The procedure may take between 3 and 6 hours, depending on the location and complexity of the aneurysm.  

What is the success rate of the treatment?

The prognosis after successful clipping is good. The procedure means the aneurysm is permanently closed.

Aneurysm coiling

With coiling, the aneurysm is closed from inside with fine platinum coils via endovascular access.

What preparations are involved?

Before the procedure, the exact situation and the degree of dilation of the aneurysm are established using CT, MRI and angiography.

The usual tests before an operation are carried out (ECG, blood-pressure reading and blood tests). Any blood-thinners must be stopped. Hospital admission is generally the day before the operation. The procedure should be done on an empty stomach.

How is the operation carried out?

Coiling of an aneurysm is performed under full anaesthetic. The microcatheter to install the coil is usually inserted via the femoral artery in the groin and moved forward to the brain aneurysm under fluoroscopy control. The aneurysm is then closed there using the coil. Sometimes a balloon or vascular stent is also used to improve fixing of the coil.

What is the success rate of the treatment?

The success rate for brain aneurysm operations using the coiling procedure is not as good as with the clipping method. In around 30% of patients, the seal with coiling is incomplete and a second coiling procedure must be carried out.

Prevention

The best measures prevent vascular diseases, particularly arteriosclerosis. This includes removing potential vascular risk factors, such as high blood pressure, lipid metabolism disorder, diabetes and smoking.

Congenital causes cannot be influenced by either medication or behaviour.