Embolization of Cerebral and Medullary Arteriovenous Malformations
Cerebral arteriovenous malformations (cerebral AVM) are congenital diseases, that is, they arise during embryonic development, and are characterized by abnormal and direct communication between the arteries and veins of the brain. These direct communications lead to an increase in pressure in the venous system that can lead to the rupture of these structures and consequent cerebral hemorrhage (hemorrhagic stroke).
The endovascular treatment of cerebral AVMs (embolization) consists of the injection of an embolic agent (a kind of glue) that will fill the entire lesion, isolating it from the cerebral blood circulation and therefore eliminating the risk of rupture and consequent bleeding. This glue is injected through small catheters that are inserted into the patient’s artery and navigated until reaching the malformation.
Depending on the anatomical characteristics of the brain AVM and the patient, embolization can be used as the only technique for the definitive treatment of the lesion or in association with other treatment modalities such as microsurgery (open surgeon) or radiosurgery.
Unruptured (non-bleeding) cerebral arteriovenous malformations can cause headaches, seizures, dizziness, loss of arm or leg strength, and even cognition impairment.
When they bleed (hemorrhagic stroke) they present as a sudden severe headache that may be associated with other symptoms such as lowered level of consciousness, mental confusion, convulsive crisis, loss of movement on one side of the body and even even coma.
Hemorrhagic stroke resulting from rupture of cerebral arteriovenous malformations are serious conditions that can lead to death or permanent neurological sequelae.
To define the best treatment option for arteriovenous malformations, cerebral angiography is essential. This exam will evaluate in detail all the characteristics of the lesion and guide the best form of treatment. Therefore, the indication of the best therapy is always individualized, taking into account the characteristics of the disease and the patient.
Currently, with the advancement of the endovascular technique (embolization) and the improvement of the materials available for the occlusion of arteriovenous malformations, the vast majority of brain aneurysms are amenable to treatment using this minimally invasive technique.
Embolization can also be used in combination with other treatment modalities such as microsurgery (open surgery) or radiosurgery (treatment of the lesion with radiation). In case of large and complex AVMs, even the 3 treatment modalities can be associated for the patient’s cure.
Embolization of cerebral arteriovenous malformations is a minimally invasive technique where it is not necessary to open the patient’s skull to treat the lesion. The surgery is performed endovascularly, that is, inside the arteries. To do this, it is necessary to perform a puncture of an artery in the patient’s leg, at the level of the groin (femoral artery) or in the arm (radial or brachial artery) and take a microcatheter to the region of the lesion and then perform its occlusion.
To perform the occlusion of the cerebral AVM, we use liquid embolic agents (a kind of glue) that will fill all the arteries and veins that form the lesion, excluding it from the cerebral blood circulation.
There are several types of embolic agents and, in some cases, other devices, such as coils, can be used for the definitive treatment of the lesion. The choice of the most suitable material will depend on the characteristics of the AVM and the patient, therefore, the choice of the best embolization technique is individualized.
It is worth mentioning that because it is a minimally invasive surgery, the patient’s recovery time is shorter compared to open surgery and in cases of AVM’s that did not bleed, the patient is discharged from the hospital in 24 to 48 hours after the surgery, being able to return to their activities. daily in less than a week.
No surgical incision is needed, just a small hole in the skin that doesn’t need special dressings.
How is Embolization performed?
Embolization is performed by filling the AVM with a liquid adhesive agent (a kind of glue) that will fill all the arteries and veins that form the lesion. This liquid is injected through small catheters (microcatheters) that are inserted into the arteries of the patient’s leg (femoral artery) or arm (radial or brachial artery) and are taken by the endovascular neurosurgeon or interventional neuroradiologist to the level of the malformation.
What is the risk of an Arteriovenous Malformation (AVM)?
The main risk of an AVM is its rupture, producing a cerebral hemorrhage, where the neurological complications are more or less serious depending on the location and size of the initial hemorrhage, and in certain cases, the patient’s death or serious sequelae may occur.
The risk of rupture of an arteriovenous malformation is 1 to 2% per year, however this rate can be very high if the lesion has some characteristics that promote bleeding, such as the presence of an aneurysm or some changes in the veins that drain the AVM.
What type of anesthesia is required for embolization of Cerebral Arteriovenous Malformation (AVM)?
Embolization of cerebral AVMs is performed under general anesthesia.
How do you find a AVM?
AVM can be diagnosed through several non-invasive tests such as Resonance / Magnetic Angioresonance or Tomography / Computed Angiotomography. Even lesions that do not show symptoms can be diagnosed through exams, they are incidental AVMs.
Cerebral Angiography is the main test to determine the structure of the malformation, the affected vessels and treatment planning.
