Treatment Options for Unruptured or Ruptured Brain Aneurysms
The two main options are endovascular treatment (which is performed through catheters inserted into arteries under x-ray guidance) and open surgical techniques. Which option is best depends on many factors: aneurysm location, size, patient condition, patient preference, and local expertise. This decision has to be made on an individual basis. Endovascular (catheter-based) treatments continue to evolve so that more and more aneurysms are now amenable to durable treatment. On the other hand, certain aneurysms are still best treated with open surgery.
The goals of treatment once an aneurysm has ruptured are to prevent further bleeding and potential permanent brain damage. Treatment and monitoring during the three weeks immediately following the hemorrhage are important, since that is the period when complications are most likely to occur. Medication and sedatives may be prescribed and total bed rest is necessary. If an aneurysm hasn’t ruptured, treatment will typically center on preventing an initial rupture using either endovascular techniques or open surgery.
Clipping is a common surgical treatment for brain aneurysms; however, it is not the preferred method of treatment by many Neurosurgeons due to how invasive the procedure is. It is an effective surgical procedure with excellent results. The primary goal of aneurysm clipping is to stop blood from flowing into the aneurysm so it cannot rupture. For very large aneurysms causing neurologic symptoms, a secondary goal of surgery is to decrease the aneurysm’s size in order reverse a patient’s symptoms. This prevents blood from entering into the aneurysm sac so that it can no longer pose a risk for bleeding. Once an aneurysm is clipped, the clip remains in place for life. The aneurysm will shrink and scar down permanently after clipping.
The first reasonably effective and safe endovascular treatment of brain aneurysms was developed in the late 1980’s. A catheter is introduced into an artery leading toward the aneurysm, similar to how it is done during Cerebral Angiography. A smaller catheter or a series of catheters are then placed into the larger guidecatheter, eventually guiding the tip of a microcatheter into the aneurysm itself. Through this catheter, detachable metal coils of appropriate size and shape are delivered into the aneurysm, gradually filling the aneurysm volume. As the coils fill the aneurysm, blood can no longer circulate in the aneurysm freely, and eventually thromboses (clots). The combination of coils and thrombus forms a plug which prevents blood from going into the aneurysm, and protects the aneurysm from rupture. Depending on the shape of the aneurysm, the coils may have a hard time staying inside. When this happens, other devices can be used to help them stay there. In the example below, a temporary balloon is inflated in the artery from which the aneurysm arises, keeping the coils from “prolapsing” out of the aneurysm until a stable configuration is achieved.
Flow Diversion/ Pipeline® Embolization
Despite advances in coil technology and devices like stents, many aneurysms still could not be adequately treated by coil embolization alone. The aneurysms are rarely perfect spheres with short necks, the way they are frequently drawn in cartoons and diagrams. Real aneurysms are complex, with irregular necks, and frequent underlying dysplasia of the artery from which the aneurysm arises. Although coils can be successfully placed into most of such aneurysms, the result is not perfect. Part of the aneurysm, especially at the bottom (neck) area, remains free from coils. This remnant is likely to continue growing, so that the aneurysm remains partially open and unprotected, sometimes requiring re-coiling, which usually leads to yet another recurrence. Some of these aneurysm go on to rupture, defeating the original point of treatment, while others eventually grow large enough to begin pressing on adjacent brain and nerves, producing symptoms such as double vision, vision loss, pain, unsteady gait, and others. The introduction of flow diverters has allowed the treatment of complex large to giant aneurysms occurring at the skull base. A flow diverter is like a more dense stent that “diverts” blood away from the aneurysm while at the same time causing local remodeling of the vessel by stimulating endothelial cell growth that covers the device. Flow diverters are mainly used in the setting of treatment of unruptured aneurysms however, some centers have been exploring the their use in acutely ruptured aneurysms.