Treatment Options for Cerebral (Brain) Aneurysms

Aneurysm shown treated with a surgically implanted clip

For over 25 years the gold standard in treating brain aneurysms has been surgical clipping, a highly durable and effective procedure performed via open brain surgery (craniotomy). During the procedure, a neurosurgeon places a tiny metal clip at the base of the aneurysm, cutting off the ballooned segment from the circulation. Complication rates associated with open surgery clipping range from eight to 10 percent.  Hospitalization after an open craniotomy to occlude an aneurysm can range from 5-10 days.  As a neurosurgeon, Dr. Lopes is highly proficient in performing these procedures, when necessary.

In comparison to coiling, clipping may offer more complete and permanent occlusion of the aneurysm. It’s estimated that approximately 2.6 percent of coiling patients experience a re-bleed versus 0.9 percent of clipping patients. For some patients, the proven efficacy of clipping may outweigh the risks associated with the invasive procedure.  While the surgical procedure hasn’t changed dramatically in several decades, Dr. Lopes reflects that patients have benefited from key refinements, such as better defined and targeted microsurgery techniques that allow for more bone resection and less brain retraction.  This has simplified the surgeon’s approach to vascular lesions.  In addition, Dr. Lopes is experienced using cooling techniques to reduce swelling-induced damage by lowering the brain’s need for blood. This is particularly useful when treating giant aneurysms.

Although clipping surgery has become safer and is a viable treatment option, in many cases, however, Dr. Lopes discusses a more minimally-invasive approach to treat the aneurysm with his patients.

Coiling

Depiction of coils being deployed into brain aneurysm.

Coiling is a catheter-assisted procedure performed by a neurointerventionalist, an endovascular-trained physician, such as Dr. Lopes. During the procedure, which is performed using advanced Siemens technology at Rush University Medical Center, flexible soft-wire coils are threaded through a catheter to the aneurysm. To start, Dr. Lopes accesses the femoral artery in the patient’s leg and navigates a catheter (small plastic tube) through the vascular system, through the neck and into the brain and into the aneurysm.  Very thin coils, made from titanium, are advanced to the aneurysm through the catheter and pushed into the aneurismal sac.  Dr. Lopes keeps pushing additional coils into the aneurysm until it is tightly packed.  Once the procedure is complete normal blood flow is re-established in the parent vessel and the risk of rupture of the aneurysm is significantly reduced, and is less than if the aneurysm was clipped. Dr. Lopes will use local anesthesia or light sedation for his patients during the aneurysm embolization procedure.  Patients will stay at Rush University Medical Center as an inpatient for 1-2 days post procedure.

Determining the best mode of treatment depends on several factors including the aneurysm’s location and size as well as the patient’s preferences and expectations. Generally, patients at high risk for surgery are better suited for endovascular intervention. This includes elderly patients and those in poor health. In addition, given the lower rate of complications and the proven efficacy of the procedure, many of Dr. Lopes’ patients have elected to undergo coiling instead of clipping for their aneurysm.

In addition to patient age, preference and size of aneurysm, several anatomical characteristics may dictate treatment as well. If an aneurysm is associated with a large hematoma, if normal blood vessel branches stem from the base or dome of the aneurysm or if the ballooned segment is pushing on nerves and is causing symptoms, Dr. Lopes may recommend clipping as a preferable treatment.

One of the major clinical trials establishing the efficacy of coiling is the International Subarachnoid Trial (ISAT).  In patients with ruptured aneurysms treatable with coiling and clipping, ISAT showed those who underwent coiling experienced better rates of independent survival at one year. This benefit was shown to last up to seven years. Even more, ISAT established coiling as a viable alternative to open surgery. Overall coiling results in lower patient mortality, shorter hospital stays and lower costs.  ISAT also demonstrated that after five years, 11 percent of the coiled group and 14 percent of the clipped group had died. The risk of death was 23 percent lower for patients with coiled aneurysms than clipped aneurysms.

Recently published, long-term ISAT data highlight one of the major shortcomings of coiling. Over time, coils may compact and allow the aneurysm to reopen and potentially rupture. According to ISAT investigators, retreatment was 6.9 percent more likely after coiling.  However, because the risk of endovascular intervention is low, undergoing multiple re-coiling procedures, versus craniotomy, may be more palatable for patients.

Advancements in coiling materials have addressed the aforementioned concerns. Biologically active coatings, suture material and hydrogels have enhanced Dr. Lopes’ ability to more completely fill the aneurysm sac. Hydrocoils, in particular, have addressed a technologic gap inherent to bare platinum coils, which left behind a small, unfilled space upon exiting the aneurysm sac. Hydrocoils coated with expanding gel appear to more completely occlude the aneurysm.

Coiling and Stenting

coiling and stanting

Some aneurysms are treated using a combination of coiling and stenting.

Historically the major factors in determining whether to use coiling were structure and location. The use of flexible stents, such as the Neuroform™ and Enterprise™ stents, has challenged that school of thought and opened new pathways for coiling. Dr, Lopes frequently acknowledges that the use of stents and coils together has been one of the biggest advancement in endovascular surgery, and consequently Dr. Lopes has performed more of these combination procedures (coiling enhanced with stenting) than most endovascular specialists in the world.

Specifically, when used in combination with coils, stenting of the parent artery now allows Dr. Lopes to safely treat aneurysms with wide-necks using the minimally-invasive coiling approach.  In addition, irregular-shaped, or fusiform, aneurysms that were once considered amenable only with surgery can also be treated with a coil and stent approach. When used in tandem, coils and stents have been shown to reduce the rate of aneurysm recurrence due to coil compaction.

Clipping and Coiling

In some cases, coiling my be used subsequent to a clipping procedure to fill part of an aneurysm that could not be fully occluded.  For example, in the case of an irregular-shaped aneurysm where clipping results in 95 percent occlusion, coiling the remaining five percent, perhaps of a small “dog-ear” segment, is plausible. Such hybrid techniques require that neurosurgeons, such as Dr. Lopes, are comfortable treating previously clipped aneurysms.

 

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