What is Aneurysm Coiling?

Cerebral aneurysm coiling, or aneurysm embolization, is a procedure to treat brain aneurysms so that they cannot bleed. This procedure is performed by highly trained endovascular neurosurgeons (or neuroinerventional surgeons) in specialized facilities, like Tallahassee Memorial Hospital’s Comprehensive Stroke Center.

Fig. 1. CT Angiogram showing a large 1.1 cm aneurysm (yellow arrow), which explains this patient’s subarachnoid hemorrhage (not shown).

Fig. 2. Diagnostic cerebral angiogram showing the right vertebral artery and basilar circulation. The large aneurysm is at the origin of the PICA vessel.

Aneurysm coiling is a minimally invasive technique for treating a brain aneurysm, where the entire procedure is performed from inside the blood vessel (an endovascular procedure). This is in contrast to the other method of treating brain aneurysm, surgical clipping. Traditionally, brain aneurysms were treated with open surgery, called clipping, where a small metal clip was placed at the neck of an aneurysm to prevent bleeding. Clipping has been the standard treatment of aneurysms since the 1960’s, and the procedure is highly invasive. Clipping involves making an incision on the scalp, removing part of the skull (a craniotomy), and then placing a clip at the base of the aneurysm.

In the 1990’s coiling was developed as a minimally invasive technique to treat brain aneurysms, and it was the first viable alternative to clipping surgery. Coiling “fixes” a brain aneurysm from inside the blood vessel, using long catheters and devices that are navigated to a brain aneurysm from a blood vessel in the patient’s leg. In much the same way that cardiologists treat heart disease with “heart catheterization” the endovascular neurosurgeon treats brain aneurysms with catheterization based endovascular procedures, or coiling.

At TMH we treat both ruptured brain aneurysms (see my post on

Fig. 3. Unsubtracted angiogram during balloon-assisted coil embolization of the ruptured PICA aneurysm. The blue line denotes the location of the parent vertebral artery as well as the small PICA blood vessel and the aneurysm. Coils can be seen in the aneurysm. The yellow line denotes the location of a balloon catheter that is helping to hold the coils in the aneurysm and protect the parent vertebral artery.

Subarachnoid Hemorrhage) as well as unruptured aneurysms. Patients who have a ruptured aneurysm have subarachnoid hemorrhage, and they are often critically ill and in the intensive care unit. Many patients who undergo coiling have unruptured aneurysms, or aneurysms that have not bled. The goal for these patients is to reduce or eliminate the risk of bleeding from the aneurysm in the future by treating high risk aneurysms with coiling.

The goal of coiling is to fill the aneurysm with platinum coils, or small devices that cause blood within the aneurysm to clot. This eliminates blood flow in the aneurysm and prevents future bleeding.

Most coiling procedures are done with the patient under general anesthesia using a biplane fluoroscopy unit. This specialized x-ray equipment is very similar to that seen in a cardiac cath lab, but it has additional features for cerebrovascular interventions.

The first step in any coiling procedure is to perform a diagnostic angiogram. This involves taking high resolution images of the blood vessels of the brain, to identify and understand the anatomy of an aneurysm. Next, a guide catheter is navigated from the femoral artery in the leg, up the aorta, and into one of the major blood vessels supplying the brain. The guide catheter is usually positioned in one of the carotid or vertebral arteries.

Fig. 4. Final result after balloon-assisted coiling with excellent embolization of the aneurysm.

After placing the guide catheter, a microcatheter is navigated within the guide catheter and then up into the blood vessels of the brain over a very small wire. This microcatheter is then carefully advanced into the aneurysm. Next, coils are placed within the aneurysm through the microcatheter. Once the aneurysm is treated, the catheters are removed and the patient is awakened.

Fig. 5a. Right middle cerebral artery aneurysm before stent-assisted coil embolization.

Fig. 5b. Right middle cerebral artery aneurysm at 6-month follow up after stent-assisted coiling with an investigational stent. There is excellent occlusion of the aneurysm.

There have been numerous advances in coiling technology over the last 10-15 years. The pace of innovation in endovascular neurosurgery is astounding, as many of the devices on the market just 10 years ago are obsolete. At TMH, we are fortunate to be able to participate in advanced device trials, helping evaluate the next generation of medical devices. Drs. Lawson and Oliver perform traditional coiling as well as advanced stent-assisted coiling, balloon-assisted coiling, and embolization using flow diversion devices.

At Tallahassee Memorial Hospital, the region’s only Comprehensive Stroke Center, aneurysm we perform roughly 100 aneurysm embolization procedures per year. Studies have shown that “high volume treatment centers,” or hospitals that care for over 50 aneurysm patients per year, have better outcomes than lower volume centers.

For more information about aneurysm treatment, check out the brain aneurysm foundation.

Share this:

One thought on “What is Aneurysm Coiling?”