What is a basilar artery aneurysm?
Basilar artery aneurysm is a condition that can lead to serious complications. It occurs when the artery’s wall balloons out.
The additional space in the artery gathers blood and disturbs normal blood flow. Like with any aneurysm, the basilar artery aneurysm is at risk of rupture, causing bleeding inside the skull. This makes it a potentially dangerous condition.
This type of aneurysm is linked to basilar artery fenestration.
What are the causes of basilar artery aneurysm?
Many factors can cause a basilar artery aneurysm. One of the primary causes is the weakening of the arteries in the brain. This condition can appear from birth as an inherited disorder, especially in families with a history of such conditions [1].
There are also other conditions related to basilar artery aneurysms, including connective tissue disorders, cerebral vasculitis, and fibromuscular dysplasia, as well as infections and vascular malformations [2].
Another cause of basilar artery aneurysms is arterial fenestration. During this rare anatomical variation of the artery, the vessel splits into two separate parts. After a certain distance, the two channels join again into one [3, 4].
Common cardiovascular factors, like hypertension and atherosclerosis, can also lead to basilar artery aneurysms. They weaken the blood vessels in the brain, thereby increasing the risk of aneurysm [5, 1].
Although rare, a dissection of the basilary artery can also lead to aneurysms [6].
The exact causes of basilar artery aneurysms are not completely clear and can be different in each case.
What are the symptoms of a basilar artery aneurysm?
Basilar artery aneurysms account for up to 5% of all cerebral aneurysms. Depending on the exact location and size of the bulging, it can present with different symptoms [7, 8].
A common symptom is progressive hearing loss. It can be accompanied by dizziness, double vision, facial numbness, or a headache in the back of the scalp [9]. Unilateral autonomic symptoms, such as headaches, can also occur [10].
Some cases of basilar artery aneurysm can present with weakness of the extremities and eye muscles. This condition is called spastic quadriparesis with sixth cranial nerve palsy [7, 8].
Additionally, affected individuals can experience brainstem infarction and vertebrobasilar insufficiency. It can present with a left hemifacial spasm, leading to twitching of the facial muscles on the left side [11].
Other reported symptoms by patients include pain and stiffness of the neck, nystagmus, nausea, headache in the back of the head, vomiting, racing heart, pareses, and pyramidal tract symptoms (like strong reflexes) [12].
In some cases, basilar artery aneurysm can also present with symptoms of posterior circulation ischemic symptoms [13]. They can include ataxia, disturbance of consciousness, and problems with eating, speech, and sight.
More prominent and stronger sight problems often indicate a risk of rapture of the aneurism. They include gradual or abrupt visual loss, double vision, or pain behind the eyes [14].
Symptoms of a brain aneurysm include
Vision difficulties, headaches, numbness or weakness on one side of the face, trouble speaking, lack of balance, pain around the eyes, difficulties with short-term memory and concentration, stiffness or pain in the neck, nausea and vomiting, and loss of consciousness or seizures.
Diagnosis and treatment of basilar artery aneurysm?
Diagnosing a basilar artery aneurysm often follows a suspicious clinical presentation of characteristic neurological symptoms. Patients with acute onset of disturbance in sight and consciousness, quadriparesis, and cranial nerve dysfunction require thorough investigation.
The standard for the diagnosis of aneurysm is angiography. The procedure allows for the visualization of the vessel's structure and the assessment of the size of the protrusion. Other methods that can be used include CT scanning and MR imaging [18, 19].
After the set diagnosis, the patient is often treated with endovascular methods. The procedures used include coil embolization, stent-assisted coiling, and balloon remodeling. The commonly used endovascular coiling often accounts for most of the treatments and leads to complete obliteration of the aneurysm in 76.9% of cases [20, 21].
The most effective method of treatment is a surgery. A surgical clip reconstruction leads to complete obliteration in 88.5% of cases [20]. However, surgery is more invasive and has a higher risk of complications; therefore, it is not the most common treatment. Around 38% of cases are treated this way.
Depending on the location and size of the aneurysm, the surgery can be performed with different approaches. The most common are subtemporal, pterional, and suboccipital [22].
In some cases, both endovascular and surgical techniques are combined to achieve better results [23].
However, despite the available treatments, the management of basilar artery aneurysms remains challenging. Factors like complex anatomy and the risk of serious complications contribute to the difficulties. Therefore, many aspects determine the treatment strategy. It has to be adjusted to the age of the patient, clinical conditions, the location and size of the aneurysm, and the experience of the responsible neurosurgeons [24].