MEDICAL BREAKTHROUGHS
RESEARCH SUMMARY
Recommended Videos
A "LEG" UP ON BRAIN ANEURYSMS
BACKGROUND: A brain aneurysm is a bulge or ballooning in a blood vessel in the brain. It often looks like a berry hanging on a stem. It can leak or rupture, causing bleeding into the brain. Brain aneurysms develop as a result of thinning and degenerating artery walls. Aneurysms often form at forks or branches in arteries where the vessel is weaker. Aneurysms can appear anywhere in the brain, but are most common at the base.
A ruptured brain aneurysm most often occurs in the space between the brain and the thin tissues covering the brain. A ruptured aneurysm quickly becomes life-threatening and requires prompt medical treatment. In about 30 percent of cases, ruptured brain aneurysms are fatal. Most, however, don't rupture, create health problems or cause symptoms. Such aneurysms are often detected during tests for other conditions. (www.mayoclinic.com)
SYMPTOMS: A sudden, severe headache is the key symptom of a ruptured aneurysm. Additional signs include: nausea and vomiting, stiff neck, blurred or double vision, sensitivity to light, seizure, drooping eyelid, loss of consciousness and confusion. In some cases, an aneurysm may leak a small amount of blood, causing a sudden, severe headache. A more severe rupture almost always follows leaking.
An unruptured brain aneurysm may produce no symptoms. However, a large unruptured aneurysm may press on brain tissues and nerves, possibly causing pain above and behind an eye, a dilated pupil, vision changes, numbness, weakness or paralysis in one side of the face or a drooping eyelid. (www.mayoclinic.com)
PIPELINE STENT: The Pipeline Embolization Device received FDA premarket approval in April 2011. Stents in general led to good outcomes. They prop up the vessel wall and when the vessel lining grows over the stent, it strengthens. Older stents, because of their mesh construction, have not been successful at redirecting blood flow; blood can flow through the mesh.
The Pipeline stent provides a mesh so tightly woven that it redirects blood flow past the aneurysm so that the aneurysm can clot off and heal. The international success rate with this flow-diverting stent has been high: 90 to 95 percent of the aneurysms treated never came back.
The stent is 75 percent cobalt chromium and 25 percent platinum tungsten; it comprises 48 densely braided strands. It is "customizable" in that multiple devices can be telescoped together, one inside the next, for longer constructs. (www.mdnews.com)
Dr. Scott Crawford Standard, Neurological Surgeon, Speacializing in the treatment of brain aneurysms at St. Thomas Hospital talks about a new FDA approved procedure that is chainging how doctors look at aneurysms.
We're here to talk about brain aneruysms, can you briefly explain to me how we get them, what happens?
Dr. Standard: Alright, the brain aneruysm is a weakness in a blood vessel so that the outside wall becomes weakend, a small bubble forms which can weaken and eventually lead to a very serious rupture in the brain hemorrhage. Usually they're caused as the blood vessel ages, sometimes they can be caused by certain genetic defects within the blood vessel wall. Most patients don't even know they have a brain aneruysm, but we find them for other reasons when a patient has a headache on the scan or perhaps a seisure. We'd like to find these before they leak a rupture, before there is a serious problem.
Can you define serious problem?
Dr. Standard: A serious problem with a brain aneruysm is a subarachnoid hemorrhage which is a massive hemorrhage within the brain that leads to very serious brain damage and very often death.
So they come to you and then you find out they have a brain aneruysm, what's the next step?
Dr. Standard: The next step is once we've identified there is a brain aneruysm is to do a test called an arteriogram, which is a dye test to look at the blood vessel in more detail. We can use the computer to reconstruct the blood vessel from the angiogram to identify exactly the size, location and the propensity of this particular aneruysm to leak a rupture.
And there is a treatment where you clip it, is that the traditional treatment you use?
Dr. Standard: The treatment for open clipping of aneruysms is to open the head and move a small section of the skull go underneath the brain and put a metal clip on the aneruysm. We use sophisticated microscopic techniques and monitoring as we're doing this to make sure that we seal the aneruysm without damaging any of the blood vessels, but it's a very laborious and very traumatic, delicate type surgery.
And afterwards is there a chance it could burst, does the clip come off?
Dr. Standard: Once the clip is placed the aneruysm is sealed and the patient is completely cured of the aneruysm in most cases, but the recovery can be quite extensive, 4-6 weeks recovery, sometimes up to a year recovering from such a brain surgery.
So now you have this different procedure called the Pipeline Stent, we use stents for many different things, why the brain and why is it different?
Dr. Standard: Well as the procedures to treat brain aneruysms have improved, the devices for treating the aneruysms have also improved and we have begun to increasingly use techniques going up throught the blood vessels threading small tubes called catheters through the blood vessels into the aneruysm or beyond the aneruysm to try to reconstruct the blood vessel from inside. These techniques have been increasingly refined over the past 15 years and been very successful in fact, revolutionized our field so that fewer patients have to undergo the trauma of craniotomy. Recently we've had some major breakthroughs in technology to actually begin to re-build or reconstruct the blood vessel directly.
This is a device called the Pipeline Stent. It is superior to older forms of coiling and other types of stenting because it actually forms a interior fabric sleeve inside the blood vessel and allows the blood to channel away from the aneruysm and forms a complety new blood vessel inside of the aneruysm.
So after you do that does it mean the aneruysm has complety disappeared?
Dr. Standard: Aneruysm will completely heal around the stent and completely go away. The remarkable thing about the Pipeline Stent is that it allows blood flow to occur through the inside of the stent but also into the very small blood vessels around the aneruysm. These blood vessels are called perforating blood vessels and they very small on the order of 1 MM or less and if any of these blood vessels are blocked off, they can cause a very serious stroke. The Pipeline allows the blood to flow through the normal blood vessel, reconstruct the blood vessel and also allow flow into the small perforating blood vessels that nourish the brain. So it truly is a reconstuctive type of procedure for the blood vessel.
Would you call this revolutionary?
Dr. Standard: Pipeline is a revolutionary advance in terms of being able to actually reconstruct blood vessels within the brain. These blood vessels are extremely fragile and so that has been the historic challenge in dealing with the brain and the brain blood vessels is that these are very delicate tissues and so the devices have to be extremely precisely engineered so that they're extremely flexible and they can enter into these very small blood vessels.
We talked about this earlier but I want to talk about it again…why did it take so long for something so different from the standard procedure to come along?
Dr. Standard: Well the technology has improved step by step over the past 15 years and each generation device gets better and better. This particular device was a unique engineering feat where a flow modeling using the very high powered computer was used to model the flow within the aneruysm, and then to actually design a device with the precise spacing of the struts to allow flow through the aneruysm and also to preserve blood flow into the small blood vessels, so it's a combination of the great advances in computing power to design the device and also marrying that with the materials technology to actually build the device that we can implant into the brain.
Would you say that this is going to replace traditional procedures?
Dr. Standard: Right now the Pipeline is approved for inoperable aneruysms, but the results have been so good and so promising that we expect it to allow us to treat many more patients that we could never treat before or patients that would require open surgery. So this is truly a revolutionary type procedure, and I think utlimately yes, it will allow us to reconstruct all different types of blood vessels either with this existing technology for future generations.
And it was just approved by the FDA, why was it used in other countries before for so long but it takes so long to get approved here?
Dr. Standard: The Pipeline device was developed about 5 years ago and it was initiated with the clinical trials in Europe and in Brazil. In those countries there's very little regulation in medical devices which is a good thing and a bad thing. The devices that are used may or may not be safe and it takes time to prove that in a large series of patients. In the US by going through the FDA process it's a very carefully managed process and very specific steps have to be taken to show that the device is not only safe but effective. A very large trial was done of over 100 patients called the Puff's Trial, the vote was so encouraging that the results of the Puff's Trial that it conviced the FDA to approve the device in the US, but that took over 3 years in very intensive of data gaining gathering.
How did you get involved?
Dr. Standard: The Pipeline Stent has become FDA approved and it is being released to select centers that do very sophisticated brain aneruysms in large volumes and as a regional referral center for brain aneruysms, we see many cases of very challenging, very complex aneruysm cases and so we were selected as one of the early sites to initiate treatment of the Pipeline Stent.
And you said very delicate cases, inoperable cases, so you think that right now that's the only cases you'll take and use the Pipeline?
Dr. Standard: Right, the Pipeline is presently approved for large or giant aneruysms in a certain segment of the blood vessel as it enters into the brain, we think that based on the good results that we're having so far that it will expand the indications, but right now it's only approved for a certain types very very challenging aneruysms. We do have other technologies that work very well for other simpler types or more routine cases.
There's pro's and con's for everything, what's the biggest pro and what's the biggest con with this?
Dr. Standard: With the Pipeline Stent, the greatest advantage is that it's a single device by going up through the blood vessels one deploys this fabric of stent along the vessel surface and reconstructs the blood vessel basically in one job. It's a faster procedure, less recovery time all done through a puncture in the groin to thread these small catheters up. As you mentioned there are disadvantages to all medical procedures and there is always risk to any procedure that we do. This is a brain surgery and there's a risk of bleeding due to the placement of the device or the use of the blood thinners that are required as we're working inside blood vessel, and so the risk of that type of bleeding is, it's a very small number but a very serious type of risk profile if that were to happen.
We just talked to Faith this morning, she's doing great and she loves you, can you tell me a little bit about her case?
Dr. Standard: Yes, Faith had a very challenging aneruysm that came to us after referrals from serveral other doctors that had no good solutions to treat her brain aneruysm. This was challenging because it was located deep within the brain and imbedded within the bone behind her eye. Surgery for this would have been very extensive to remove bone behind the skull base to gain access to this particular area. Because of the challenges of her particular case she was referred to us for consideration of this innovative Pipeline procedure and she was really an ideal candidate for the procedure. We were able to reconstruct the entire segment of her aneruysmal blood vessel with a single stent.
How is she doing right now medically?
Dr. Standard: She's done extremely well, we've been very pleased-she's actually ahead of schedule in terms of recovery, she went home several days earlier than we had expected from the initial procedure, and her nuerologic function is excellent, she has had no signs of any type of ill effects from the procedure what so ever.
Are there any restrictions?
Dr. Standard: There are some small reasons why a patients could not have a Pipeline Stent, the main one would be if there's very limited way to gain access to the particular area of where the aneruysm is located, many patients have twists and turns in the blood vessel that make it very diffucult or challenging to get the devises in the position, and also it's necessary to treat these patients with powerful blood thinners and if there's a history where the patient might have had an allergy to the thinners, they would not be a candidate for the Pipeline Stent.
Compared to the recovery time of the original or the traditional surgery can you give me those numbers?
Dr. Standard: Well the recovery from a tradional surgery is 6 weeks to 3 months altogether in terms of recovery. Recovery from a inter-vasular procedure such as a Pipeline is only about 10 days to two weeks; so patients can resume their normal activities much quicker in a much more robust fashion than they could after any type of traditional surgery.
Because it could be something that's genetic, is that something they have to worry about the rest of their lives?
Dr. Standard: Once the aneruysm is repaired either with the Pipelind Stent or some other technique, the aneruysm is completely cured and so the risk of the patient having further problems is really basically eliminated.
FOR MORE INFORMATION, PLEASE CONTACT:
Tina Morehead
Howell Allen Clinic
(615) 341-7435
tmorehead@howellallen.com