Aneurysm Clipping and Coiling Brain Surgery

Candidates for an Aneurysm Clipping or Coiling

A brain aneurysm is a balloon-like bulge that develops in the wall of its parent artery. As the aneurysm grows, the artery wall weakens and the aneurysm may leak or rupture, causing blood to release into the brain. Most aneurysms are saccular, meaning they are shaped like a balloon with a small neck expanding into a dome. These are the easiest aneurysms to treat. Others have a wider neck or no definable neck, at all, known as fusiform. These are more difficult to clip or coil and may require stenting.

The treatment for an aneurysm will depend on the shape of the aneurysm itself, its location and the overall health of the patient. Clipping the aneurysm at its neck is an invasive procedure and may not be recommended for patients who are older and in poor health. Coiling is a noninvasive procedure, however, the longevity of a coil is less definitive than that of a clip. When deciding upon the course of treatment (observation, clipping or coiling) the risk of rupture of the aneurysm must be weighed.

What is an Aneurysm Clipping or Coiling?

Aneurysm clipping and coiling are two separate methods of treating an aneurysm. The strategy for either option will also differ if the aneurysm has ruptured versus if it has not. If the aneurysm has ruptured and is bleeding into the brain, known as a subarachnoid hemorrhage (SAH), the timing of the treatment is very important and is usually completed within 72 hours of the first bleed as the risk for repeated bleeding is 22% within the first 14 days. An SAH may also result in narrowing of the artery, or vasospasm. There is a 40% risk of death and 80% risk of disability when an aneurysm ruptures.

If the aneurysm has not ruptured, symptoms may not be present and it may have been detected through routine testing for other conditions. There is less risk associated with an unruptured aneurysm (about 1% risk of rupture per year) but risk may vary depending on the size, shape and location of the aneurysm.

Therefore, treatment strategies will vary.

If clipping is the method of treatment and the aneurysm has not ruptured, certain preparations will be made prior to surgery including relevant tests, stopping medications, refraining from smoking and drinking alcohol, and not eating or drinking after midnight the day before surgery. The procedure will be performed under general anesthesia and will typically take 3-5 hours. 

Once the patient is asleep, his or her head is placed in a three-pin skull fixation device attached to the operating table to prevent movement. The incision area is prepped and a lumbar drain may be placed in the lower back to remove cerebrospinal fluid in order to relax the brain. An incision is made to the scalp and muscles to reveal the skull. A craniotomy is performed to remove a portion of the skull known as a bone flap, in order to access the brain and locate the aneurysm. Once the aneurysm is located, the surgeon will obtain control of the blood flow and prepare the neck of the aneurysm for clipping. 

The aneurysm must be isolated and small surrounding arteries must not be included in the clip. The clip is held open with a tweezer-like applier until the correct positioning is found. Once the clip is placed, the surgeon will ensure it is not narrowing the parent artery and that no additional arteries were clipped. The titanium clip will remain in place permanently and several clips may be used. The surgeon will then check the aneurysm to be sure it is no longer filling with blood.

Once the clip is in place and checked, the surgeon will then close the craniotomy and replace the bone flap with titanium plates and screws. The muscles and skin are sutured back together to close the incision and a dressing is placed over it.

The same preparations are made when undergoing a coiling procedure in which the aneurysm has not ruptured. During the procedure, the patient lies on his or her back and is given general anesthesia and anti-clotting medication. The patient’s head is positioned so that it won’t move during the procedure. The area of injection is prepped and the femoral artery in the groin area is located. The entire procedure typically takes 2-4 hours.

A hollow needle is inserted into the artery and then a catheter is passed through the needle to enter the bloodstream. Dye is injected through the catheter to make blood vessels visible on the x-ray monitor. Using the x-ray visuals, the surgeon guides the catheter through the bloodstream up the aorta, passing the heart and entering one of the four arteries in the neck that lead to the brain. Once the catheter is correctly placed, the surgeon continues to inject the dye to map and measure the arteries and aneurysm.

A smaller catheter is inserted through the first catheter up into the aneurysm, through which platinum coils are inserted into the aneurysm. The surgeon maintains visuals by continuing to inject dye to ensure the placement of the coils. Once the coils are properly placed, the surgeon then releases them and continues packing the aneurysm with coils. A stent, or mesh tube, may be necessary to hold the coils in place. Once all coils are placed and the surgeon confirms proper blood flow, the catheters are removed. Pressure is applied to the injection site in the groin area to prevent the artery from bleeding.

If the aneurysm has already ruptured, there is no time for the aforementioned preparations. The patient is stabilized so the providers may locate the hemorrhage. The patient may immediately be taken into the operating room and given medication to decrease blood pressure, put on a breathing machine or sedated.

Results of an Aneurysm Clipping or Coiling Procedure

Aneurysms that have been completely clipped are not likely to grow back, however, if the aneurysm was only partially clipped, the patient will need to undergo periodic angiograms to ensure the aneurysm is not growing.

If the aneurysm was coiled, long-term results are about 80-85% effective. About 20% of patients experience recurrence due to the coils not completely blocking the aneurysm or becoming compacted. The aneurysm should be checked regularly to measure regrowth and if a major portion of the aneurysm does regrow, the patient may require another surgery. Additional coils or a clip may be placed to stop the growth. About 5-10% of patients will need a second surgery.

Due to the risk of regrowth in coiling patients, surgeons will typically recommend the patient returns after six, 12 and 24 months for an angiogram. If the aneurysm ruptured, the patient should return after three months.

Most patients who undergo an aneurysm clipping or coiling of an unruptured aneurysm can expect to live normal lives. If the aneurysm has ruptured, recovery may be more difficult with challenges ranging from minor to more severe. Short-term memory loss and headaches are common. Some deficits may lessen through healing and therapy.

Most modern aneurysm clips are made of titanium and won’t be detected in a security scan. However, it is important to know the compatibility of the clip with an MRI machine before undergoing an MRI scan.

What are the risks of an Aneurysm Clipping or Coiling?

Aside from the ever-present risks of surgery, complications of an aneurysm clipping or coiling center around the regrowth or rupture of the aneurysm. The risk of vasospasm, stroke, seizure, bleeding and imperfect clip or coil placement are present. Brain surgeries also risk infection, allergic reactions to anesthesia and swelling of the brain.