Aneurysm is a balloon-like structural impairment developing at junctions of blood vessels. And an arteriovenous malformation (AVM), shortly referred to as AVM, is an issue where arteries and veins are connected directly, because no capillary system has developed in between, and there is somewhat a tangle of blood vessels with weak walls. Both aneurysm and AVM have congenital weakness in walls of blood vessels.

Who can get aneurysm?

It occurs mostly in young males and females. We encounter aneurysm in cranial blood vessels in 10-14% of autopsies, but not all bleed during the entire lifetime. Around 10% of aneurysm causes bleeding in brain due to an aneurysm rupture. The prevalence of AVM is six times higher than that of aneurysm despite its prevalence differs amongst races.

People who have a family history of brain aneurysms are more likely to have an aneurysm in their children than those who do not. Those who have polycystic kidney, aortic stenosis, some rheumatic diseases are more likely to have aneurysm than general population. For those who have the disease, a brain MR angiogram should be made to investigate whether or not aneurysm exists. A non-bleeding aneurysm is more advantageous than a bleeding aneurysm.

How does aneurysm develop?

The blood vessels in brain which develop aneurysm do not have muscle-like structures around, unlike other parts in the body. And in aneurysm, the muscular layer at the wall of blood vessels is relatively weaker. When this weakness becomes distinct at the branching location of blood vessels, it creates a weaker location in there. The reasons such as pressure inside the blood vessel, smoking, and others causing atherosclerosis may lead to bulging of this weak point in a balloon-like structure – also making it wider, and aneurysm develops.

It is more congenital reasons that play a role in developing AVM. Instead of a capillary system, an abnormal tangle of blood vessels develops where arteries and veins connect directly. Capillaries are the thin blood vessels through which blood stream contacts the tissues and performs the exchange of energy. AVM tangle next to the capillary consisting of thinner blood vessels serves as a medium where blood flows more easily. Since the diameter of blood vessel is bigger, for it consists of thicker blood vessels, there is no resistance against the flow of blood, which is why the blood that is supposed to go to capillaries, flows through AVM blood vessels, which is much easier.

What are the symptoms of aneurysm?

Aneurysm and AVM tangle with a thinner wall will rupture and cause bleeding when they can not bear the blood pressure inside. Most of the time, aneurysm causes subarachnoid hemorrhage, as it opens into cerebrospinal fluid under the arachnoid space on the surface of the brain. AVM mostly bleeds into brain, rupturing brain tissue and causing intracranial pressure syndrome due to masses caused by clots.

Patients with a bleeding in brain fall into five categories depending on severity of situation. The first three groups can be surgically treated and those in the fourth and fifth groups can only be given intensive care support. If their situation improves and if they go up to higher groups, they can be treated, too. However, most of them die unfortunately.

What is the treatment applied by Dr. Yunus Aydın?

Through microsurgery method, if the particular case allows for it, aneurysm and AVM are put in a state where blood can not get inside. The neck of aneurysm is sealed off with a small clip similar to a hair pin. And through the microsurgery technique, AVM is removed by sealing-off the blood vessels feeding the AVM.

What are the alternative treatment methods for aneurysm?

When the inside of aneurysm does not allow for surgery, they are filled with a small tangle of wires, similar to a wire wool, and blood flow is blocked. Although this procedure seems to be advantageous with no need for a surgery, it has a drawback, because it requires periodic monitoring as blood can get inside again, and it may require the same procedure to be performed again, when required. The aneurysms which are closed with a clip do not require any such monitoring after a post-operation control.

An option for the AVMs which do not allow for surgery and are located deep inside and are smaller than 25 mm in diameter is burning with gamma ray (Gamma knife). Although this procedure is advantageous as it does not require opening of skull, it has also drawback, because the gamma rays can heal AVM in 3 years after the surgery. The most important drawback here is that patient continues to take the risk of bleeding during this period of time, whereas, after a good surgery removes AVM, there will be no more risk of bleeding.

Another method for AVMs is embolization which means injecting glue-like materials into blood vessels which afterwards freeze and get solid. This method breaks the rules of fluids dynamics of AVM and causes easier bleeding in situations where it can not block the flow completely or due to filling of the abnormal blood vessels that has newly commissioned after the embolization. It is a method which I do not use, and I have never used in any of more than 400 AVM surgeries I have performed. However, there are colleagues who use this method before surgery and move onto surgery right after that. They suggest that there is less blood during surgery; however some patients may actually bleed during this procedure, which poses a risk by itself which I do not prefer to take. An experienced surgeon can perform surgery without embolization. There are many surgeons who share the same opinion with me in our country and around the world.

What if aneurysm is not treated?

As part of today’s health system applications, people can easily and frequently have a brain MR due to many simple reasons, so aneurysms are diagnosed by chance before they actually cause any cerebral hemorrhage. Some other times, big aneurysms show themselves by pressing on adjacent nerve structures and get caught before bleeding. Regardless of the way aneurysms are noticed, aneurysms cause bleeding in the brain, if not treated. One third of the patients with a bleeding aneurysm, die at time and at the place bleeding starts. The remaining 2/3 of patients comes to hospital, who can fall into 5 groups. The first 3 groups can be treated, and the ones in the fourth and fifth groups are in a serious situation. They should first be treated in intensive care treatment and if they improve and go up to first three groups, they may have a chance of getting treated. Unfortunately, most of those in the last two groups die.

Post-op course in aneurysm

The most important issue that threatens patients in the first three groups is re-bleeding. The only procedure that prevents re-bleeding is the treatment at the early stage, the surgery. For those who are not eligible for surgery and those for whom surgery would be risky, the aneurysms which are located in posterior fossa are generally filled with pieces of metal (generally coil made of platinum), and are put out of circulation.

There is no need for an immediate surgery for the patients with a bleeding AVM but in good condition. Time should be allowed for the edema – which has developed after the bleeding- to disappear, which should then be followed by the surgery. However, surgery must be done as soon as possible if there is massive bleeding and the mass in the brain has extremely increased the intracranial pressure.

After the surgery, those who do not need a ventilation support are taken into regular room the next day. Those who have no weakness can leave hospital in 4-5 days, and those who have are transferred to the rehabilitation clinics.

How to avoid aneurysm?

Smoking eases aneurysm bleeding, so we can add also this to the list of the many other reasons for which you should stop smoking. If you suffer from high blood tension, treatment should not be interrupted. If anyone in your family has aneurysm, you can have a brain scan with an MR angiogram.