Cerebral Aneurysm

A cerebral aneurysm, also called a brain aneurysm, occurs when a weakened area in the wall of a blood vessel in the brain bulges outward, forming a balloon-like shape. The exact cause is not always known, but some people may have a family history of brain aneurysms.

Most brain aneurysms do not cause symptoms and are often discovered during imaging tests for other medical conditions. However, an aneurysm can sometimes rupture (burst), causing bleeding in or around the brain. This type of bleeding, called a subarachnoid hemorrhage, is a life-threatening medical emergency that can lead to serious brain damage, disability, or death.

Not all brain aneurysms rupture, but it can be difficult to predict which ones will. For this reason, your doctor may recommend neurosurgical treatment even if an aneurysm is discovered during testing for another condition and is not causing symptoms. Both small and large aneurysms can rupture, so size alone does not determine the risk. Your doctor will consider the aneurysm's size, location, and other factors to determine whether treatment or regular monitoring is the best option for you.

Some people may have more than one brain aneurysm. If you have a family history of brain aneurysms, talk to your doctor about whether screening may be appropriate for you.

Types of Neurosurgical Intervention

These are broadly divided into microsurgery (via craniotomy, or opening of the skull) and endovascular (catheter-based techniques that are performed through a tiny incision in the leg, instead of opening the skull).

Microsurgical clipping is performed using an operating microscope at the base of the brain, after a craniotomy is performed. Once the aneurysm is isolated after tracing its parent blood vessel, a titanium clip is applied in such a way as to exclude the aneurysm from the normal circulation, which is preserved.

Endovascular neurosurgery is also known as Interventional Neuroradiology. Endovascular techniques for cerebral aneurysm include platinum microcoils (deposited within the aneurysm), stents (used to bridge the bottom of some aneurysms), and balloons (used to widen constricted blood vessels, or sometimes in conjunction with coils).

In coil embolization for aneurysm, the aneurysm is excluded from the normal circulation by the deposition of platinum microcoils delivered through a microcatheter entering the body from the leg. No incision is made on the head. Once an aneurysm is coiled, it is recommended to undergo cerebral angiography at half-year intervals for 2 years, to monitor the permanence of occlusion.

Procedures performed by Dr. Thomas, whether microsurgical or endovascular, are under general anesthesia and are usually attended by neurophysiologic monitoring, which is the monitoring of the brain's electrical activity, to maximize the safety of these procedures.

Endovascular and microsurgical techniques can be combined effectively for optimal treatment of complex conditions.

Which form of intervention is safest for the patient is a complex medical decision based on the shape and size of the aneurysm, the experience of the physician in the different procedures, and on the health and preferences of the patient. Both techniques are forms of brain surgery, and require the highest levels of experience and clinical judgment.

Because of the dangerous nature and complexity of cerebral aneurysms, it is advantageous for the neurosurgeon to have access to all current treatment modalities. This makes for balanced, thoughtful treatment decisions. Sometimes multiple modalities may be used for a single patient.

Most cerebral aneurysms can be eliminated successfully using a measured and well-planned approach to treatment.

See aans.org for more information.

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