Detachable coil embolization offers a new approach to treating aneurysms and other blood vessel malformations in the brain. A brain aneurysm, or weakness in the arterial wall, is a serious medical condition. If an aneurysm ruptures, internal bleeding may cause a stroke or loss of life. In less severe cases, a bulging aneurysm may compress surrounding nerves and brain tissue resulting in nerve paralysis, headache, neck and upper back pain as well as nausea and vomiting. Cerebral angiography, computed tomography (CT) or magnetic resonance (MR) imaging can detect aneurysms prior to rupturing.
Interventional neuroradiologists perform detachable coil embolization to alleviate much of the danger presented by aneurysms. The interventional neuroradiologist inserts a tube, called a catheter, into an artery in the leg. This catheter is then manoeuvred through the body to the aneurysm's position. Once in position, the radiologist places one or more small coils through the catheter into the aneurysm. The body responds by forming a blood clot around the coil that strengthens the weak spot in the artery.
Detachable coils may also be used to treat a rare intracranial congenital vascular condition called arteriovenous malformation. In this instance, the brain's arteries and veins are not connected by capillaries but are linked instead by abnormal connections called arteriovenous fistulas. These fistulas may empty the arteries of blood before cerebral circulation is completed. This abnormal blood exchange between cerebral arteries and veins may cause headaches, haemorrhage, seizures and strokes, as well as neurological symptoms impacting memory, movement, speech and vision.
Coils can be used to either block blood flow to the affected area or to fill the aneurysm or fistula, thus preventing a rupture. Occasionally, additional coils may be inserted during a subsequent procedure to complete treatment.
Using detachable coils to close off the aneurysm or fistula is effective in prolonging life and relieving symptoms. Unsuccessful attempts were originally made to fill aneurysms with detachable balloons without rupturing the aneurysm. To minimize the risk of rupture, researchers developed soft, detachable coils. Coil embolization currently is used to treat approximately 30 percent of cerebral aneurysms and 20 percent of arteriovenous malformations.