BRAIN ANEURYSM

An aneurysm is a bulging of the vessel wall caused by weakness. These weak areas can involve the entire vessel wall (fusiform), bulge outward from only a portion of the wall (saccular), or separate the layers of the vessel wall (dissecting). Aneurysms can occur in any vessel in the body. When aneurysms in the brain rupture, they can cause severe brain damage and death.

Aneurysms can occur in 6 out of every 100 people in the general population. They are more common in women. More than one aneurysm can occur simultaneously in one-fifth of patients. They are most common between the ages of 40 and 60. The most important risk factors are smoking and a family history of aneurysms.

How is aneurysm diagnosed?

Unfortunately, most aneurysms are not detected until they rupture, causing a brain hemorrhage. Sometimes, large aneurysms can cause symptoms such as visual disturbances, pain behind the eye, headaches, and nerve palsies before they rupture. Because brain magnetic resonance imaging (MRI) and brain CT scans are more frequently performed today than in the past, a greater proportion of these aneurysms are detected before they rupture. MRI and CT scans can detect the presence of an aneurysm, but cerebral angiography is necessary for detailed aneurysm evaluation and treatment planning. An angiogram is performed to visualize the brain and neck vessels by inserting a thin, flexible tube called a catheter into an artery in the groin area. It is then advanced to the neck vessels, where a fluid is injected that makes the vessels visible under X-rays. Detailed images of the vessels are obtained from various angles, and the relevant vessels are evaluated. Characteristics of the aneurysm, such as its size, shape, and location, are evaluated, and this information is used to select the most appropriate treatment method and techniques.

What happens if the aneurysm bursts (ruptures)?

When an aneurysm ruptures, blood fills the space between the meninges (subarachnoid hemorrhage), causing a severe headache. Patients sometimes describe this headache as "the worst headache of their life" or "a bomb exploded in my head or a lightning strike." Other symptoms include nausea, vomiting, impaired consciousness, weakness, or drowsiness. A subarachnoid hemorrhage is an emergency, and approximately one-fifth of patients die before reaching the hospital. 40-50% of patients who reach the hospital die within the first 30 days. Half of those who survive will become disabled if they do not receive the necessary treatment.

Patients who experience a brain hemorrhage due to an aneurysm often remain in the intensive care unit for up to two weeks. Hydrocephalus, a swelling and fluid accumulation in the brain cavities, can occur following the hemorrhage. This can lead to increased intracranial pressure and may require the insertion of a draining tube to relieve the pressure. Blood in the brain cavities can also cause the vessels to constrict and contract (vasospasm). Because vasospasm reduces the amount of blood reaching the brain, strokes can occur in these patients. To prevent this, patients are given vasodilators in the intensive care unit, and their blood pressure is maintained at a high level. If these treatments are unsuccessful, patients may need to undergo repeat cerebral angiography, which involves intravenous injections of vasodilators or balloon dilation of the blood vessels.

How are aneurysms treated?

If an aneurysm has caused a brain hemorrhage, it must be treated. Some aneurysms detected before causing bleeding do not require treatment at all. Very small aneurysms discovered incidentally can be monitored closely without treatment. Experts in this field make treatment recommendations based on the aneurysm's size, location, and patient history. There are two treatment options: open surgery (or clipping) and closed surgery (or endovascular).

Open Surgery

In the open procedure, neurosurgeons incise the skin, open the skull, access the area of the brain where the aneurysm is located, and place a metal clip around the neck of the aneurysm. This prevents blood flow into the aneurysm.

Closed-Endovascular Method

In the closed approach, interventional neuroradiologists approach the aneurysm from the groin artery using a similar approach to cerebral angiography, accessing the neck and brain vessels, respectively, using very thin catheters. They then use various techniques to isolate the aneurysm from the bloodstream. The most common of these methods is filling the aneurysm with platinum coils. Stents and balloons can also be used to assist with the coiling process. Another method involves inserting a special stent, called a flow diverter, into the vessel containing the aneurysm, without entering the aneurysm itself. This diverts blood flow away from the aneurysm and redirects it back to normal circulation. This reduces pressure within the aneurysm, and the aneurysm eventually collapses on its own. The most appropriate technique is selected based on the aneurysm's size, shape, location, and relationship to adjacent vessels. Patients undergoing stent treatment should be taking blood-thinning medications before the procedure.

While both methods are effective, the closed approach is currently the first choice for the vast majority of aneurysms. Its lower risk and greater comfort compared to open surgery have brought the closed approach to prominence worldwide. The most comprehensive studies have shown that closed (endovascular) treatment results in less disability and death compared to open surgery. Furthermore, patients undergoing the closed approach have a lower rate of epilepsy and cognitive decline.