Endovascular neurosurgery is a discipline that combines neurosurgery with a field called “interventional neuroradiology.” Instead of open operations, this minimally-invasive technique uses x-ray imaging, catheters, and various embolic (clotting) agents to treat diseases of the blood vessels of the brain and spine. The “surgery” is performed in a fluoroscopy suite rather than an operating room, and the procedure is done within the blood vessels by using catheters to fill blood vessel abnormalities with obstructing particles, polymers or stents (see "An Aneurysm Treatment Primer" below to understand the illustrations).
Diagnostic neuroradiology was invented by a neurosurgeon, Egas Moniz, many years ago. More recently, interventional neuroradiology is becoming more commonplace. The more common diseases treated include carotid artery stenosis, cerebral aneurysms, arteriovenous malformations (AVMs) of the brain and spine, and dural AVMs of the brain and spine. Occasionally, brain tumors can also be treated with a combination of endovascular surgery and open neurosurgical procedures.
Historically, the techniques of interventional neuroradiology were used along with open neurosurgery. Currently, many of these techniques can be the only treatment necessary for various diseases. An example of this is the treatment of complex cerebral aneurysms when the risk of open operations exceed the risk of endovascular surgery. Some aneurysms, due to the size or location within the brain, are very difficult to treat successfully and safely with traditional neurosurgical techniques. Over the last decade, the effectiveness and safety of endovascular neurosurgery has improved and catheter techniques have become the treatment of choice for certain aneurysms.
This can be the case with cerebral aneurysms near the brainstem such as basilar artery aneurysms. Endovascular surgery of cerebral aneurysms is performed by placing a flexible catheter within the femoral artery (the artery supplying the leg) and advancing the catheter into the arteries which feed the aneurysm within the head. Detachable coils and stents can be injected to block the flow of blood into the aneurysm and cause the aneurysm to become clotted. A team of experienced neurosurgeons and interventional radiologists can best determine treatment for these challenging problems.
Endovascular techniques can treat a variety of intracranial disorders:
Carotid cavernous sinus fistulae
Cerebral revascularization after clotting
An aneurysm of the basilar artery, situated at the base of the brain and technically difficult to operate, was successfully treated by endovascular coils.
A side-view of the rounded aneurysm filled with dye at the top of the basilar artery. After six coils have been placed through a catheter in the basilar artery, the aneurysm no longer fills with blood.
An Aneurysm Treatment Primer
A cerebral aneurysm is a saccular bulging of the wall of an artery. The cause is a structural weakness in the wall of the artery. For hydrodynamic reasons, these bulges appear at places where arteries divide into smaller branches. These aneurysms slowly enlarge with time and may rupture causing bleeding within the brain. Many individuals do not survive spontaneous hemorrhage for aneurysms.
Individuals who survive an initial hemorrhage may be treated by open surgery to obliterate the aneurysm or endovascular methods to fill the aneurysm with clot. Endovascular methods avoid open surgery but can only be used in selected cases.