March 28, 2011

A Revolutionary Procedure in Aneurysm Treatment
By Carolyn Gutierrez
For The Record
Vol. 23 No. 6 P. 24

A North Carolina surgical team takes advantage of perfect circumstances to make history.

By integrating their expertise in neurosurgery and ear, nose, and throat (ENT) anatomy, two surgeons at the University of North Carolina (UNC) at Chapel Hill School of Medicine and UNC Health Care recently performed an unprecedented surgical procedure to treat aneurysms during which they used surgical clipping through the nasal cavity.

Anand Germanwala, MD, an assistant professor in the department of surgery’s division of neurosurgery, and his surgical partner, Adam Zanation, MD, an assistant professor in the department of otolaryngology, devised a less invasive alternative to traditional brain surgery, accessing aneurysms located at the base of the skull through an endoscopic endonasal approach.

Two Established Treatment Paths
A brain aneurysm, which is a bubble or a blister on a blood vessel in the brain, is potentially deadly if it bleeds, with about 40% of patients with ruptured brain aneurysms dying as a result. Since the 1960s, U.S. brain surgeons have traditionally treated aneurysms through a transcranial operation known as surgical clipping in which a miniscule metal clip seals off blood circulation at the neck of the aneurysm.

“We remove a portion of the skull, lift the brain up because we want to get at the base of the brain, and we find the aneurysm and put a metal clip on it,” explains Germanwala. “The advantage of this procedure is that the clips are very strong, and the aneurysms do not tend to come back if we can get them all treated by the clip. The disadvantage is that it’s maximally invasive. It’s major brain surgery. Bone is removed temporarily, [and] you’ve got to manipulate the brain, lift the brain up, put some pressure on the brain, and then do your surgery. These patients are usually in the hospital for five to seven days at a minimum.”

The decision to treat an aneurysm with surgical clipping depends on factors such as the location of the aneurysm and a patient’s age. The best candidates are often younger, healthier patients who will recover more easily from the general anesthesia needed for major surgery. Complications are possible during surgical clipping and can include infection, rupturing of the aneurysm during surgery, damage to the artery, and bleeding on the brain, causing various degrees of neurological damage. Complications or additional hemorrhaging during surgery could prolong a patient’s hospital stay by one to four weeks or longer. After surgical clipping, patients may also experience temporary memory problems, headaches, fatigue, and dizziness.

A second brain aneurysm treatment developed in the early 1990s called endovascular coiling involves running a catheter through the femoral artery in a patient’s leg all the way up the body to the inside of the brain and into the aneurysm. Small platinum coils are released from the catheter into the aneurysm sac. These springlike coils, which are about twice as thick as a human hair, form a kind of mesh within the aneurysm, causing the blood within the aneurysm to coagulate and thus seal it off from the blood’s circulation.

The main advantage of endovascular coiling is that it is less invasive; patients don’t have to endure major brain surgery, and many leave the hospital within one day. But according to Germanwala, “The disadvantage is that sometimes the aneurysms do come back because the coils are not as strong as the clip. And these patients have to be monitored with x-rays. We typically do them at six, 12, and 24 months. They have to go through procedures to see if the aneurysm is coming back. About 20% to 30% of those aneurysms do come back, so the disadvantage of the endovascular coiling is that it’s not as permanent as clipping.”

Although there are still risks involved with the procedure, older aneurysm patients may benefit more from the less invasive endovascular coiling since they are generally more vulnerable to postsurgical complications. As endovascular coiling is a more recent treatment option, the medical community has not yet confirmed long-term outcomes. However, short-term studies have indicated that the newer procedure seems to have lowered the mortality and morbidity rates of many aneurysm patients.

A New Approach to Treating Aneurysms
In addition to the surgical clipping and endovascular coiling of aneurysms, one of Germanwala’s main interests is the treatment of brain tumors, particularly those located at the midline of the skull’s base, such as pituitary tumors, meningiomas, and craniopharyngiomas. “A brain tumor and a brain aneurysm are completely different,” notes Germanwala, “A brain aneurysm is like sprinting a mile. A brain tumor is like walking a marathon. It’s a completely different beast. Brain aneurysms (cerebrovascular neurosurgery) are essentially ticking time bombs and, if they rupture, can result in instant death. Therefore, during aneurysm surgery, the dissection has to be extremely precise. Small movement errors can lead to catastrophic problems. … Brain tumors are usually more slow growing and do not have the capability of ‘exploding’ in front of the surgeon and lead to instant death. Blood vessels have to be manipulated far less [frequently] during brain tumor surgery compared to aneurysm surgery.”

Through his collaboration with Zanation, an ENT surgeon, Germanwala has excised hundreds of brain tumors through an endoscopic endonasal approach. After Zanation accesses and cleans out the back of the nose where it meets the base of a patient’s skull, he holds a 4-mm camera that enables Germanwala to perform surgery via a TV monitor.

Two years ago, Germanwala and his colleagues encountered an emergency department patient with a possible ruptured aneurysm. When imaging was done on the 42-year-old woman, it was determined that she had not one but two aneurysms, the larger of which had ruptured. Both aneurysms were found at the base of the skull (where the vast majority of aneurysms occur) and were located in the midline of the skull.

“Both of [her aneurysms] were in the location where I often operate for a brain tumor,” says Germanwala. “I looked at the imaging … and thought, ‘I have experience with the traditional clipping [and] I have experience with the endovascular coiling, so I have experience with aneurysms. And I also have experience going though the nose.’

“I obviously met the patient first, and she was fortunately in a state where she could understand everything that I was telling her and her family,” he continues. “I described to her what she had and what the standard options were. I preferred clipping in her particular case over coiling because she was so young. I wanted a permanent solution, and I wanted a strong repair of the aneurysms. The first decision I made was that [her aneurysms] should have clipping. Then, looking at the film, seeing where the aneurysms were, I thought we could actually do this through the nose, which was completely unprecedented. I talked to her and she had tremendous trust in me and agreed for me to do this [procedure] in this particular way.”

After conferring about their plan of action and preparing for surgery, Germanwala and Zanation set in motion the teamwork between their two specialties that would result in a life saved and the birth of a new procedure. “Together we drilled the bone, then [Zanation] held the camera. Basically I opened the lining of the brain, exposed the two aneurysms, and was able to put surgical clips on both of them,” says Germanwala.

The surgeons found that essentially the endoscopic endonasal procedure combined the best features of the two mainstream treatments: the nasal cavity yielding a less invasive path to the aneurysms and the clipping providing a more durable resolution.
When the procedure was completed, an angiogram was performed in the operating room to reaffirm that the clipping had successfully closed off the patient’s aneurysms. The results were favorable; the patient was up and walking hours after the procedure and had no neurological deficits. Two years later, she is still doing fine and no aneurysms have occurred.

Germanwala and his team remain cautiously optimistic about the endoscopic endonasal approach. “It is just one case,” Germanwala notes. “We’ve got to keep that in mind. It’s two aneurysms. [The procedure is] in the early stages. It did open my eyes, and I think it opened the eyes of a lot of my colleagues in the country to whom I presented this particular case. We can do this. The key is determining who is the right patient.”

On that day two years ago, Germanwala’s aneurysm patient happened to present with the perfect set of variables to undergo the new procedure. Plus, his surgical team possessed a perfect skill set that accentuated the interplay between specialties required for this unconventional procedure.

“It’s a very challenging skill set to have,” says Germanwala, “because you have to have a brain surgeon that can clip aneurysms, can go through the nose, and has familiarity with the anatomy through a camera on a monitor. You also have to have a brain surgeon who works well with an ENT physician who’s going to be willing to do this for the entire team.”

Ruptured vs. Unruptured Aneurysms
Although potentially life threatening, not all unruptured aneurysms must be treated. Based on the size, shape, and location of the aneurysm, physicians can usually determine which ones are more dangerous. Patients with very small aneurysms that do not appear to pose a threat are generally monitored, with special attention paid to any changes in the aneurysm. Blood pressure, cholesterol levels, and other lab results are also inspected periodically.

“On average, there is a 1% chance of bleeding per year from an unruptured aneurysm,” says Germanwala. “Most 40-year-old people in this country, on average, live to about 80, so over 40 years, at 1% per year, that means Mrs. Jones, who I’m seeing in clinic at the age of 40 with an unruptured aneurysm, has about a 40% chance in her lifetime that the aneurysm will bleed. I’ve got to determine what gives Mrs. Jones more risk: doing something to her aneurysm or leaving the aneurysm alone.”

A patient’s age and general health is also taken into account. “If I see a 90-year-old patient with an unruptured aneurysm and a 20-year-old patient with an unruptured aneurysm, those are two very different discussions,” notes Germanwala.

Because of the high mortality rate, patients with ruptured aneurysms require emergency care. If a patient has not died as a result of the first bleeding, there is a strong possibility that a second bleeding will occur in a matter of hours to days, increasing risk for death. Treatment for a bleeding aneurysm must be initiated within 24 hours of onset.

Patients with ruptured aneurysms often describe their primary symptom as the worst headache ever. Other symptoms may include vomiting, neck stiffness, impaired vision, sensitivity to light, and strokelike symptoms, including loss of memory or speech and a lack of sensation or a feeling of numbness throughout the body. Physicians suspecting a ruptured aneurysm generally conduct a CT scan in attempt to detect a subarachnoid hemorrhage, or a pattern of blood usually seen with ruptured aneurysms. If a subarachnoid hemorrhage is found, the patient undergoes an angiogram, the gold-standard test for detecting ruptured aneurysms on blood vessels in the brain.

Patients with unruptured aneurysms generally do not experience symptoms. Given the increased accessibility of MRIs and other state-of-the-art imaging, the discovery of an unruptured aneurysm is more likely to be an incidental finding during an examination for another condition or ailment.

Risk Factors
In the United States, 1% to 2% of the population has an aneurysm. Scientists and neurosurgeons such as Germanwala are trying to determine why this part of the population is at risk of the condition.

“There are a few things that we know of in 2011 that predispose you to aneurysms,” says Germanwala. “The biggest one is that if you have had one brain aneurysm, you have an approximately 16% to 20% chance of having a second aneurysm. Having a personal history of an aneurysm increases your risk.”

Other risk factors include environmental toxins, smoking, and high blood pressure. “There are certain syndromes such as polycystic kidney disease and some collagen vascular diseases that can predispose you to developing aneurysms,” notes Germanwala, adding that for the majority of patients, it’s an unpredictable occurrence.

Germanwala suspects there is a genetic component that may predispose certain patients to aneurysms. “What my lab is investigating is the genes that are involved in aneurysm formation. What my lab is actually doing at the minute is investigating certain families that I have treated where more than one family member is affected,” he says. “I have families where three to four individuals had aneurysms. There has to be a genetic component; we just have not identified it yet.”

— Carolyn Gutierrez is a freelance writer based in New York City.