Health

YES, IT IS BRAIN SURGERY

A neurosurgeon and his team have to react calmly when a blood vessel bursts during an operation

MARK BERNSTEIN October 14 2002
Health

YES, IT IS BRAIN SURGERY

A neurosurgeon and his team have to react calmly when a blood vessel bursts during an operation

MARK BERNSTEIN October 14 2002

YES, IT IS BRAIN SURGERY

Health

A neurosurgeon and his team have to react calmly when a blood vessel bursts during an operation

MARK BERNSTEIN

MIKE IS ENJOYING his son’s Saturday morning soccer game and kidding with the other soccer dads on the sideline when he falls over with a sudden headache, as if someone had hit him over the head with a baseball bat. An ambulance takes Mike (for the purposes of this article, a composite of typical aneurysm patients) to a local hospital. There a CT scan confirms a subarachnoid hemorrhage—a bubble on a blood vessel deep in his brain has popped. When he fully comes to, Mike discovers he’s been taken to the neurosurgery unit at Toronto Western Hospital. As his neurosurgeon, I try to be as positive as possible as I tell him that an aneurysm that has ruptured in his brain has to be fixed. It’s very risky surgery, but it has to be done.

Mike’s wife sneaks away from the bedside and cries quietly. What would she and the three kids do without Mike, who’s just three weeks shy of his 35 th birthday? Called in on a Saturday for this emergency, I discuss the situation with my senior resident and the anaesthesiologist, and let the nurses in the OR know to get things set up. The thin blister on the blood vessel deep in the brain lies in wait for us like a bomb ready to explode and take the patient’s life with it. We suit up in our riot gear.

THE PATIENT has been anaesthetized and his head fixed in a metal clamp attached to the operating table. The left side of the scalp has been shaved, cleansed and draped in sterile sheets. The operation begins just after noon with a long, curved incision from in front of the ear to above the eye. Then the resident and I cut and peel the scalp and underlying muscle off the bone. Using an air-powered drill and saw, we remove a window of bone the size of a playing card. The brain is tense as we open the dura, the wet, leathery covering. The fluid surrounding

the brain is stained from the blood that escaped from the aneurysm when it exploded a few short hours ago.

We peer at the arachnoid membrane, a wispy, translucent skin covering the brain like Cellophane. We can see the Sylvian fissure, cleft between the temporal and frontal lobes. We move the operating microscope into position on its ceiling track and the resident and I adjust our eyepieces. Focusing on the brain’s surface, we use small forceps, dissecting tools and scissors to open the Sylvian fissure progressively down to two inches below the surface. Then we use the metal blades of retractors to pull the lobes apart, exposing the optic nerve and, just beside it, the internal carotid artery, one of the large vessels carrying blood to the brain. We have found our blood vessel highway, along which we will gently navigate in search of the enemy.

Step by step we dissect the brain off the carotid artery and exert more retraction. I hear one of the nurses talking about a social commitment she has this evening with her husband. I have been unaware of time and space for the last little while. I quickly wonder what my wife and daughters are doing on this beautiful weekend.

As we get about an inch along the carotid artery, we come to the place where it divides into the anterior cerebral and the middle cerebral arteries. The preoperative angiogram has shown us that the culprit aneurysm is on the middle cerebral. After more painstaking dissection under the operating microscope, we come to the point where that artery divides into many daughter branches. Now we can see the object of our pursuit. The aneurysm, the size of a small olive, is embraced by three good-sized daughter arteries which snake by to fulfill their vital task of providing oxygenated blood to the brain.

An aneurysm is a thin-walled blister that pouches out from the side of an artery because of a defect in its wall. The defect is present at birth, but it usually takes decades for the blister to expand and rupture. The dome of the aneurysm has a thin, transparent wall through which we can see the blood swirling violently. Viewed through the microscope, this is a frightening sight.

The object is to place a spring-loaded metal clip across the base of the aneurysm to exclude it from the general blood circulation and thus prevent rebleeding. If a patient is fortunate enough to survive the first rupture of an aneurysm, the second time is usually fatal. The challenge is to avoid leaving any of the aneurysm wall behind to collect blood, enlarge and bleed again, and to do so without pinching off any other arteries, some the size of a hair, because that could produce a devastating stroke for the patient.

The dome of the aneurysm has a thin, transparent wall through which we can see the blood swirling violently. Viewed through the microscope, this is a frightening sight.

So with delicate dissecting instruments we start to define the neck of the aneurysm, the narrow area where the bulb rises out of

the artery. We do this by gendy getting between the daughter arteries plastered to the aneurysm and the aneurysm itself with fine metal probes. The dissection goes slowly because if you’re too rough or too fast, you can rip a hole in the aneurysm, instandy converting a controlled situation into a horrifying, potentially disastrous crisis. Your heart pounds, your eyes strain and every muscle in your body tenses to place your head and hands in a perfect position. Apart from the “beep-beep” of the anaesthetic machine, there is silence in the operating room as we work away.

The safest way to get the arteries off

the aneurysm, we decide, is to be a bit rougher. First, though, we want to place a temporary clip across the trunk of the middle cerebral artery to decrease the pressure on the aneurysm and to ensure that bleeding would be non-catastrophic if it did rupture during our manipulations. We put the clip on and ask a nurse to monitor the time. Generally one only has a few minutes to work with a clip in place without risking a stroke. We continue to try to dissect off the daughter arteries, but it’s tough going—it’s like they were glued on. “One minute,” announces the nurse. We continue, trying to establish a good enough slot for the clip to cut off the entire aneurysm but spare vital vessels around it. “Two minutes,” says the nurse.

At this pace of bleeding the patient could die from blood loss alone in about 60 seconds, yet if we stop the flow too quickly, we could irreversibly injure the brain by damaging vital small arteries

I’m not happy with our progress and decide to withdraw the temporary clip from the middle cerebral trunk. I become aware of my heart thumping painfully against my breast bone. My throat is dry as a chip as I whisper to my senior assistant, “I guess we’ll have to take the bull by the horns and just do this without a temporary clip.” I’m really seeking her endorsement and support, rather than dictating strategy.

We get up for a moment and walk over to the X-ray viewing monitor to look at the angiogram. We both know this is a stalling tactic to allow us to catch our breath. We return to our posts on either side of the microscope and pick up our weapons. I decide the only way to get a good look at one of the daughter arteries as it passes behind the aneurysm is to move the aneurysm dome with a flat, spatula-like dissector.

I picked this technique up from one of my senior, now-retired colleagues who helped me and many other neurosurgeons learn to do aneurysm surgery. It is a risk that has to be taken if we want to get on and clip this aneurysm. I start to gently but firmly retract the aneurysm—and then it happens. The beautiful, crystal-clear but surrealistic view of aneurysm, middle cerebral artery trunk, daughter vessels and brain disappears in a swirling sea of red that rises rapidly toward us. The aneurysm has ruptured.

Blood rushes into our operative field. Although not an uncommon occurrence during this type of surgery, it is truly frightening, something akin to the horror when your car hits a patch of ice and starts to slide at 100 km/h. There are some corrective measures you can take, but the outcome is unpredictable. At this pace of

bleeding, the patient could die from blood loss alone in about 60 seconds, yet if we stop the flow too quickly, we could irreversibly injure the brain by damaging vital small arteries. My heart skips a few beats.

With two suckers vacuuming the blood, the resident and I work to compress the aneurysm with a bit of cloth about one centimetre square. “You better just put the clip across the aneurysm neck,” I say, “and then we’ll look around and make sure it’s safe.” After a few runs with the applicator forceps at different angles, she deftly slips the clip into place. I take the cloth off and there is no bleeding. We then retract the aneurysm to check whether the artery on the other side is free, only to find it squished in the blades of the clip. My heart skips a few more beats.

If we left it like this, the patient would have a serious stroke with speech problems and weakness of the right arm and leg. So again I press the cloth back on the aneurysm dome with a sucker tip to prevent bleeding, and the resident removes the clip and repositions it at a slightly different angle. Inspection now reveals that no vital artery has been trapped. The job is done.

I gasp and allow my muscles to relax a bit. I ask the anaesthesiologist how the patient is doing and he replies, “Solid as a rock.” My head and the resident’s move away from the eyepieces of the microscope and we make eye contact. Our brows are furrowed and our faces too stiff to move, but our eyes smile.

I look up at the clock on the wall. Three hours and 20 minutes have passed since we cut skin. It seems like 15 minutes. I feel exhilarated and at the same time spent— emotionally and physically. We remove pooled blood from the brain, make sure there are no active bleeding points, remove the retractors, stitch together the dura, replace the bone flap with little metal plates, and close the scalp.

Mike was cured. He woke up in fine shape and went on to be discharged a few days later. As he had slept through it all, and his wife did not witness this little war we waged in the operating room, they will never know just how close to death this husband and father had been. 171

Dr. Mark Bernstein is a professor of surgery at the University of Toronto and head of the division of neurosurgery at Toronto Western Hospital.