Aneurysms: Neuroradiologic Treatment
Guest: Dr. Aquilla “Quill” Turk – Radiology/Neuro Interventional
Host: Dr. Linda Austin – Psychiatry
Dr. Linda Austin: I am Dr. Linda Austin. Today, I am interviewing Dr. “Quill” Turk who is Associate Professor of Radiology and a specialist in the area of neuroradiologic treatment of a variety of disorders of the brain.
Let’s start today, if we can, Dr. Turk, by talking about brain aneurysms. Can you explain, first, what is an aneurysm in the brain?
Dr. Quill Turk: Brain aneurysms are essentially weak spots on a blood vessel wall that cause an abnormal out-pouching. You can think of it as a ballooning out of the blood vessel in a focal area. The easiest way to picture that would be similar to a car tire with a bubble on the side poking out where there is a defect in the tire wall. We obviously get concerned because tires tend to blow out from that area, so we change the tire. Aneurysms do the same thing where they are abnormally ballooned out in these areas of weakness.
Dr. Linda Austin: How would a person with an aneurysm become aware that they had that condition?
Dr. Quill Turk: Most aneurysms present one of two ways. The aneurysm can rupture, in which case people present with usually the worst headache of their life, or they have an episode of loss of consciousness and they basically pass out and are taken to the hospital and a lot of people do not survive that initial event. The other way people present is they will get a scan of their head, an MR scan or a CT scan related to an injury, a headache, or a cranial nerve, such as one that controls their eyes not working correctly, and the scan will uncover this abnormal out-pouching of the blood vessel.
Dr. Linda Austin: And obviously that is a much better situation because you have a chance to do something about it.
Dr. Quill Turk: Absolutely. It is a much more controlled situation.
Dr. Linda Austin: Because the first situation you described where there is rupture actually is what amounts to a stroke.
Dr. Quill Turk: Yes. The first situation is a bleeding type of stroke and that is an emergency situation where patients are admitted emergently to the hospital. They are taken emergently to surgery to fix the aneurysm and they typically wind up spending several weeks in the intensive care unit, managing all the complications that are associated with that bleeding episode and to see if they even survive that event.
Dr. Linda Austin: So, I am sure then, as a neuroradiologist, your approach to those two different kinds of presentations must be very different.
Dr. Quill Turk: It is. There is a clear dichotomy in approaching someone who comes in electively versus coming in during an emergent situation. People that come in electively, in general, we talk to them about an aneurysm being something that is formed over time. It is a process that they have likely had for quite awhile. It is related to a degenerative process in the blood vessel wall, although there is a small subset of people who have a familial type of inherited aneurysms. But the strict definition of that means that they have two direct family members who have aneurysms that have ruptured, meaning, brother, sister, mother or father. And they know this history because they have had their aneurysms rupture. Also, when they rupture, they tend happen at a younger age, usually in their 30s or 40s, as opposed to most aneurysms that occur in the general population that are spontaneous which tend to occur a little later, usually patients in their 50s or 60s.
Dr. Linda Austin: Now, in the situation which the aneurysm has first been spotted as an incidental finding, do you need to do further diagnostic evaluations studies before you decide how you are going to treat that?
Dr. Quill Turk: When people present to us with an elective aneurysm, we want to have some type of study that shows us the characteristics, so they need an angiogram of some sort. Often times it can be done non-invasively with a CT scan or an MR scan. We need to know the location of the aneurysm, its size, and some type of understanding as to its shape. In other words, if it is an aneurysm that is shaped like a balloon where there is a small opening and a larger body to the aneurysm versus an aneurysm that is more like a small blister, or a small bump with no definable opening to the aneurysm, that will help determine the type of treatment that we could offer that person.
Dr. Linda Austin: How do you go about treating these aneurysms?
Dr. Quill Turk: Well, that is a complex question that there is a lot of controversy around in that, in general, we always talk to people about the natural history of the aneurysm, which is probably the most important thing. We want to make sure that we are not posing more of a danger offering a surgery than leaving the aneurysm untreated. In general, most people have about a one percent chance per year of the aneurysm rupturing. That is kind of a general figure that we give. However, that is variable depending on the size and location of the aneurysm, the larger the aneurysm, the higher the chance for it to bleed. If it is located in the blood vessels in the back of the brain, the posterior circulation, it has a higher chance of bleeding than one located in the blood vessels in the front of the brain.
So it is very dependent on the location and the size. It also depends on the patient, how old they are, what their state of health is, because, as we said, most of the time this occurs in patients that are older. So you have to make sure that the risks associated with the surgery, there is a three to five percent chance that something bad could happen, and when we say, bad, we usually talk about the aneurysm rupturing during surgery or causing a stroke which could leave someone with the inability to use an arm or a leg. That obviously has to offset the risk of them hurting themselves, a one percent chance per year, roughly.
Dr. Linda Austin: So, then, if you find this in a younger person, let’s say, somebody in their 20s and 30s, would you be more likely to operate, thinking that over the course of, say, 50 years, they would have a 50 percent chance, I suppose, of something happening?
Dr. Quill Turk: Absolutely. The longer someone’s projected lifespan, and that is always a difficult topic to address because, you know, we all like to think we have plenty of time left, it really comes down to quality of life, so clearly the younger a person is, the higher their benefit is to have the aneurysm treated.
Dr. Linda Austin: So let’s talk then about the treatment. Let’s say it is a young healthy person, a lesion that is large enough that you’re worried about it, how do you treat it?
Dr. Quill Turk: There are really two ways to treat aneurysms. One is through the newer way which we perform through the blood vessels, called coiling. It is done through an endovascular route where you access over the femoral artery in the groin area. We access through the blood vessels to the ones that go to the brain and then through that, we are able to take a tiny catheter and go into the aneurysm itself and deposit small coils to block off the aneurysm from the blood supply.
Dr. Linda Austin: How big are the coils?
Dr. Quill Turk: The coils range in size from about 2.5 cm down to about 2 mm in diameter. We have them in varying lengths, shapes, levels of softness, so we can really tailor the coil for the aneurysm that we are treating.
Dr. Linda Austin: How long does that procedure take?
Dr. Quill Turk: It depends on the size of the aneurysm. Larger aneurysms take a little longer, smaller aneurysms are usually a little faster, but it usually takes about two hours.
Dr. Linda Austin: And, I would assume, done under general anesthesia?
Dr. Quill Turk: Yes. Whenever we do these, we put the patient asleep. It just makes for a more controlled environment.
Dr. Linda Austin: What kind of success rate do you have with this procedure?
Dr. Quill Turk: In the high 90 percent. It is very uncommon for us to not be successful treating an aneurysm, especially one that presents electively, as we were discussing. We are able to look at the anatomy and make sure that it looks favorable for our treatment ahead of time.
What we have to do is follow-up. We have to monitor patients. We usually do this with MRI and MRA scanning to ensure the treatment was as effective as we thought. Sometimes, between 5 and 15 percent of the time, patients will have to come back and have a re-treatment because sometimes the coils can be compacted or a small area of the aneurysm can re-grow.
Dr. Linda Austin: Now, you mentioned earlier that there are two ways of treating it. What is the alternative?
Dr. Quill Turk: The more traditional method is the surgical clipping where they do a craniotomy, or a window in the bone, and they use a microscope to gently dissect between the spaces of the brain. Then, from the outside, they put a clip across the opening of the aneurysm to block it off from the circulation.
Dr. Linda Austin: Do we still do that procedure here at the medical university?
Dr. Quill Turk: Yes.
Dr. Linda Austin: But you do not, yourself, do it?
Dr. Quill Turk: No.
Dr. Linda Austin: Because you are a radiologist?
Dr. Quill Turk: Correct. We operate as a team, composed of neurosurgeons and radiologists, and we approach these aneurysms together and discuss all cases as a group. What we try to offer these patients is the greatest benefit for the lowest risk by coming up with a tailored approach to each patient individually.
Dr. Linda Austin: So, then, are there clinical situations which might call for the more traditional approach, the craniotomy with the clips as opposed to the coils?
Dr. Quill Turk: Absolutely. The majority of the time, patients hear about both options as well as their advantages and disadvantages. Both options are available actually for probably the majority of aneurysms so it really comes down to patient preference, understanding the pros and cons of both approaches.
Dr. Linda Austin: What are you observing in how patients choose? What percent of those who are offered both options choose one over the other?
Dr. Quill Turk: Sure. There has certainly been a large movement toward the endovascular coiling of aneurysms. I think most people find it very appealing because with the coiling of an aneurysm, patients come in the morning of the surgery, we treat their aneurysm, they spend the night in the intensive care unit and they go home the next day. They basically have a Band-Aid on their groin and they can essentially return to normal activities within a couple of days, so it is a much more minimally invasive surgery although it does carry the same significant risks as an open surgery.
Dr. Linda Austin: How many years has this been done?
Dr. Quill Turk: The coiling of aneurysms as been fairly widespread for about 15 years now.
Dr. Linda Austin: So that is a pretty long term. And is it generally then a definitive procedure, you do not have to go back and have it done again?
Dr. Quill Turk: We do monitor patients with MR scanning and, again, occasionally, somewhere between 5 and 15 percent of patients will have to come back for a re-treatment. There are some situations in which the coils are in a very high-flow situation and can become compacted or the area at the base of the aneurysm can sometimes re-grow. But we do follow people after their coilings to watch for this and if they need to, we can go back and perform what we call a touch-up surgery in a very controlled environment.
Dr. Linda Austin: And what percentage of patients who have an aneurysm, let’s say, successfully treated, will go on at some point to develop a second aneurysm somewhere else in their brain?
Dr. Quill Turk: That is always a hard question. It is a pretty small number of patients though. We are talking probably in the single to double digits.
Dr. Linda Austin: So it is not a generalized recurrent problem? It is just a fluke that has happened at some point?
Dr. Quill Turk: Correct. When we have patients that resume with aneurysms, it is up to about 20 percent of people who actually have more than one. So it is certainly not unheard of but it is not the norm for people to have more than one.
Dr. Linda Austin: Dr. Turk, thank you so much for talking with us today.
Dr. Quill Turk: Thank you.
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