Oct 24, 2023

Case Study: Embolization and Resection of a Complex Arteriovenous Malformation

Last spring, a 41-year-old man was home with his wife when she noticed that he seemed confused and was struggling to find the right words. Shortly thereafter, he had a seizure and temporarily lost consciousness. He was taken to the Overlake Medical Center Emergency Department, where imaging revealed a large inferior frontal lobe arteriovenous malformation (AVM) in his dominant left hemisphere, near the primary language areas.

The patient was put on an anti-seizure medication and referred to the Eastside Neuroscience Institute, which brings together world-class neurosurgeons, neurologists, complex spine surgeons and advanced practice providers from Overlake and EvergreenHealth.

“The seizure was a warning shot that alerted everyone to the AVM and enabled us to make a plan,” says neurosurgeon Dustin Hayward, MD.

Dr. Hayward and his colleagues see roughly 10 or more new patients with AVMs each year – a high volume given that AVMs are detected in approximately one in 100,000 people. For this patient, the team performed a diagnostic cerebral angiogram to grade the AVM and evaluate three potential treatment options: observation, stereotactic radiosurgery and microsurgical resection.

“This was a complex case – it was especially important to weigh all the options because of the AVM’s proximity to the language areas,” Dr. Hayward says.

Weighing the risks of observation versus resection

The team determined that, if the AVM was left untreated, this patient faced a 60% chance of a potentially devastating rupture and hemorrhage. Then they considered that in the context of the risks of treatment.

“Radiosurgery or resection can damage language areas, and a statistical estimate based on generalized data showed a 20% risk that a patient like this would end up with a neurological deficit,” Dr. Hayward says. “At our center, we believe the risk is lower because providers have fellowship training in microneurosurgery and other areas, extensive experience with these procedures and access to state-of-the-art technology. But there’s always risk and it’s something you need to think very carefully about.”

After the team determined the AVM was too large to be treated with radiosurgery, Dr. Hayward his colleagues talked the patient and his wife through the advantages and disadvantages of resecting the AVM versus an observational approach. The patient decided on surgical resection.

Innovative neurointerventional embolization

Our team takes a collaborative, multidisciplinary approach – every case is brought to a conference that includes neurosurgeons, neurologists and radiation oncologists. This enables us to evaluate patients from every angle, trade ideas and map out tailored treatment options.

Together, the team evaluated the treatment options for the lesion. The neurosurgeon and neurologist started identifying which arteries fed the AVM and not the brain, and which veins drained the AVM. This helped the surgical team understand which arteries to block and remove.

“The guiding principle is that you want to stop the inflow to the AVM but not the outflow, but it’s tricky because the arteries look quite similar to the veins, and you risk hemorrhage if you block the outflow first,” Dr. Hayward says.

The procedure started in our neurointerventional suite with biplane angiography capabilities – which is among just a small handful of such suites in our region – where Dr. Hayward and his colleagues performed neurointerventional embolization to start reducing the number of arteries feeding the AVM.  

“We used microcatheters to inject glue and start blocking the AVM’s blood supply,” he says.  

The next day, Dr. Hayward and an experienced team of scrub technicians, circulating registered nurses, anesthesiologists, neuromonitoring specialists and surgical assistants performed the surgical resection. They relied on advanced equipment including a surgical microscope and intraoperative cerebral angiography.

“A procedure like this is like dismantling a bomb – it requires extraordinary attention to detail as you work to identify and remove the correct blood vessels, without affecting the tissue around them,” Dr. Hayward says. “As you start taking the arteries, you see the veins turn from red to blue, and that’s how you know you’re winning the battle.”

Once the team finished the resection, intraoperative angiography confirmed the AVM was entirely removed.

“We use intraoperative cerebral angiogram on all of our vascular neurosurgery cases,” Dr. Hayward says. “It confirmed that there wasn’t any residual AVM and that all the major blood vessels were still open.”

When the patient woke up, he was neurologically intact. Today, he is healthy and back to normal life.

“We were all thrilled with his outcome, and it’s a great example of how combining specialized expertise, teamwork and the latest technologies enables us to minimize risk and pursue best possible outcome for each patient,” Dr. Hayward says.

Comprehensive care, tailored to each patient

Our team’s comprehensive approach goes beyond safely removing an AVM. For example, we do our best to ensure that a patient’s appearance stays the same after surgery.

“We’re very careful with cranial reconstruction,” Dr. Hayward says. “We make sure the temporalis muscle is reattached to its attachment points and we use an absorbable suture so there’s no staple or suture removal.”

This exemplifies how we put patients first, by carefully considering how their condition and treatment could affect all aspects of their lives.

“Every detail matters when we’re making a clinical decision,” Dr. Hayward says. “Everyone on our team – every nurse, every physician, every staff member – goes out of their way to build a relationship with the patient, and we want to know things like what they do for a living, what their family life is like, which hand is dominant, how they spent their time and what’s important to them in life. We take all those things into consideration, which helps us achieve great outcomes and is why I’m always happy when patients find us.”

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