Endovascular Coil Insertion


Endovascular coiling is a minimally invasive endovascular alternative to surgery for treating brain aneurysms. An interventional neuroradiologist inserts a catheter into an artery (usually in the groin) and threads it through the body to the site of the aneurysm. Using a guide wire, detachable coils are passed through the catheter and released into the aneurysm.

A brain aneurysm is a weakening of the brain’s blood vessels, causing the vessel to balloon outwards, forming an aneurysm. Brain aneurysms typically occur in the area of the brain known as the subarachnoid space.  Once an aneurysm forms, the blood vessel itself is at risk of bursting, causing internal bleeding. If undetected or left untreated, internal bleeding can cause severe illness, such as blindness, paralysis, coma or even death. Symptoms of a ruptured aneurysm include:

  • Sudden headache

  • Seizures

  • Speech impairment

  • Muscle weakness

  • Confusion or cognitive changes

  • Vision changes

The risk factors for developing cerebral aneurysms are:

  • Smoking

  • Excessive drinking

  • High blood pressure (hypertension)

  • Family history of aneurysms

Because unruptured cerebral aneurysms show no symptoms, they may go undetected until they burst, at which point treatment is urgent and should take place within 72 hours.

Neurosurgical clipping can also be used to treat a brain aneurysm and is the more traditional surgical method for treating ruptured aneurysms. During the procedure, the surgeon uses a small clip to “seal off” the aneurysm from the outside. A neurosurgeon removes a section of the skull, locates the blood vessel that feeds the aneurysm and places a small, metal clip on the neck of the aneurysm to halt its blood supply. The clip remains in place and reduces the risk of future bleeding.

A patient may be able to return home the next day following the endovascular coiling procedure for an unruptured aneurysm. If the aneurysm has ruptured, the patient may be monitored and treated for several days by a team of specialists in the intensive care unit. These patients may also require neurological and psychological rehabilitation to help them return to their normal, independent lives and activities.

Using SPECT (Single Photon Emission Computed Tomography), scanning, specialists can watch for signs of vasospasm before it occurs. A type of therapy known as hypertensive, hypervolemic, hemodilutional, or HHH, along with a drug called nimodipine, can help reduce the risk of vasospasm. For those patients who develop severe vasospasm, doctors can open up or dilate the brain’s blood supply using a tiny balloon inserted directly into the affected blood vessels.



Medications given after surgery for an aneurysm are designed to prevent a condition known as vasospasm, or a narrowing of the blood vessels in the brain.



There are many things to keep in mind when deciding which therapy is best for treating an aneurysm. Usually, endovascular coiling is recommended for small, more rounded types of aneurysms. Neurovascular clipping may be suitable in a large, broad-necked type of aneurysm.  Endovascular coiling is considered safer than clipping. However, because of an increased risk of bleeding associated with endovascular coiling, neurovascular clipping may be a more appropriate option for some patients.



The effectiveness of endovascular coiling compared to surgical clipping depends on several factors. Studies have shown that larger aneurysms and aneurysms with large necks may recur with endovascular treatment. For these types of aneurysms, about one third may recur and are usually treated surgically by clipping. Neurosurgical clipping may be especially helpful for younger patients, whereas older patients may minimize their side effects by endovascular coiling.

Be sure to talk to your doctor about the best option for you or your loved one.


Risks of Treatment

While all treatments for aneurysms carry some risks, an experienced surgeon can help reduce unwanted side effects. Studies have shown that coiling is generally safer than clipping, in large part because a craniotomy (opening the head) need not be performed.

The risk of death from coiling is approximately 1 percent and the risk of a stroke is approximately 3 to 5 percent.


Risk of No Treatment

In patients with a ruptured aneurysm, treatment is almost always recommended because the risk of a second hemorrhage is high. About one out of three patients will experience a recurrence within one month. Half of patients will experience a recurrence in six months, and as many as 85 percent of those patients may die from the second hemorrhage. Prompt treatment for a ruptured aneurysm is highly advisable.


In the case of unruptured aneurysms, the decision to treat will depend on many factors. The risk that an unruptured aneurysm might rupture is very low. For aneurysms smaller than half an inch (10 mm), the risk is approximately less than 1 percent a year. For larger aneurysms, the risk of rupture is higher. In addition to size, other factors can increase the risk of rupture:

  • Location of the aneurysm

  • Evidence of multiple aneurysms

  • A history of a bleeding from a previous aneurysm

An experienced surgeon can help the patient make the right treatment decision.



In patients with a ruptured aneurysm, treatment is urgent and is usually carried out within 72 hours. If the rupture has caused heavy internal bleeding, treatment may be required immediately.

With unruptured aneurysms, treatment is less urgent, allowing time to discuss therapeutic options. If treatment is appropriate, the doctor and patient can work together to determine which treatment – endovascular coiling or surgical clipping – is best for the patient.

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