A cerebral aneurysm is a pathological dilation of the wall of a blood vessel, usually an artery, present in the brain. This swelling of the arterial vessel is created by the flattening of the vessel wall, often favored by hypertension problems. In the point where it is weakest, the wall stretches, thins and dilates. As shown in the figure, in the end, very often the aneurysm appears as a sort of sac, communicating with the artery through a small hole , called the neck or collar, through which the blood that fills it passes. The presence of a brain aneurysm is clearly a very dangerous condition. If the brain aneurysm were to rupture, in fact, the consequence is a hemorrhage that can cause irreversible damage to brain, up to the permanent vegetative state and death. Often cerebral aneurysms do not cause obvious symptoms, so much so that they can occasionally be recognized during medical tests performed for other reasons. The most representative symptom in the event of a ruptured aneurysm is a strong headache, sudden, violent and often associated with symptoms of neurological damage, such as blurred and double vision or facial paralysis. and surgery make it possible to identify and intervene preventively on most cerebral aneurysms at risk of rupture.
Cerebral aneurysms are often due to a congenital defect of the arterial wall. In other words, the wall of the blood vessel affected by the aneurysm may be dilated and thin from birth. However, aneurysms can also arise due to other conditions, or in any case be favored by them; among these we remember head injuries, arterial hypertension, atherosclerosis and some diseases of the connective tissue. In many other cases, however, the origin of the aneurysms remains unknown. Among the predisposing factors there are certainly also an incorrect lifestyle, such as smoking or the abuse of alcohol and drugs. Additionally, brain aneurysms occur more commonly in adults and are prevalent in the 40 to 60 age group. It is estimated that in Italy about 5-10% of the population lives with a brain aneurysm, of which two thirds are women. The risk of rupture depends on the location and size of the aneurysm itself, for example if it is larger than one centimeter the risk of rupture doubles.
Normally, it is not easy to recognize the symptoms of a cerebral aneurysm, since it is a silent, asymptomatic disorder or in any case with very vague signals, which become dramatic only when the aneurysm ruptures. Only in some cases, the aneurysm reaches dimensions. such as to cause symptoms of “mass effect.” In these circumstances, by strongly compressing the brain tissue, or the adjacent nervous structures, the aneurysm can cause the appearance of a neurological deficit. As anticipated, the most frightening complication is the rupture of the thin walls of the aneurysm, which can cause massive blood loss within the brain. The sac wall, in fact, is weak because it does not have the normal structure of an artery, so it can break if the blood pressure inside it suddenly increases. A cerebral hemorrhage is clearly a dangerous event, which, if not surgically treated in time, can have lethal effects. It is therefore important not to underestimate the warning signs. We know, for example, that the bleeding is accompanied by a sudden and excruciating headache, similar to a stab in the back of the head. After the rupture, bleeding can cause double vision, severe nausea and vomiting, loss of consciousness, confusion, tightening of the neck muscles and general malaise.
If the aforementioned ailments appear, you obviously don't have to waste time, as blood loss due to ruptured aneurysms requires immediate medical attention. A brain CT scan is done first, which shows that there is bleeding. Another very important exam is cerebral angiography; this exam studies in detail the course of the cerebral vessels, then highlights the anatomical variations and serves to give information on the location, size and shape of the aneurysm. It is performed by introducing a catheter that from the femoral artery, through the main vessels, is made to rise up to reach the intracranial vessels. Once in position, a contrast medium is injected into the tube which allows to obtain the complete morphological and dynamic visualization of the cerebral flow. Further information for a correct treatment planning is provided by the magnetic resonance.
Surgery undoubtedly plays an important preventive role. The most appropriate type of surgery is established based on the characteristics and location of the aneurysm. The direct surgical approach, under general anesthesia and with open skull, consists in placing a special titanium microclip to close the aneurysm collar, that is the junction between the healthy part of the artery and the dilation. In this way, the aneurysm sac is excluded and isolated from the bloodstream, without interfering with the surrounding arteries. This microsurgery technique is called clipping. Alternatively, endovascular treatment can be performed in patients considered to be at risk. This method is also aimed at closing the aneurysm, but this time from the inside, that is by introducing thin metal filaments into the pouch by means of an angiography. This is the so-called endovascular embolization treatment, also called coiling; in practice, the presence of the metal spirals has the task of inducing blood coagulation at the level of the aneurysm; in this way a thrombus is formed, a clot that acts as a plug, closing the collar and excluding the dilation from the bloodstream. Today, surgical mortality is limited, but it is not always possible to get to surgery, because in some cases the initial cerebral hemorrhage is immediately fatal. Other patients have a more or less complete recovery. After the closure of the aneurysm, absolute bed rest and drug therapies are indicated to promote coagulation, reduce intracranial pressure and avoid vasospasm, that is, the pathological narrowing of the cerebral vessels.
