Springfield Neurological and Spine Institute - "Glue" Reduces Risk for Brain Surgery Patients

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"Glue" Reduces Risk for Brain Surgery Patients

Thursday, August 21, 2008

"Glue" Reduces Risk for Brain Surgery Patients

Published June 5, 2006 in the Springfield News-Leader

Sealant plugs abnormal blood vessels and lessens chance of hemorrhaging or rupture.

By Kathleen O'Dell
News-Leader

A new "glue" has revolutionized treatment for Ozarks patients with a rare brain disorder.

The sealant sets up slowly and plugs tangled, abnormal blood vessels, reducing the risk for hemorrhage or rupture.

That allows surgeons to stabilize a patient's condition before surgically removing the glued bundle, greatly reducing the risk of a life-threatening rupture on the operating table, said Springfield neurosurgeon Dr. Edwin Cunningham.

The Onyx Liquid Embolic System is a leap forward in pre-surgical treatment of AVMs, or arterio-venous malformation.

But Cunningham sees a bigger promise: "AVM surgery is a big operation," he said. "In the future, we could cure a lot of them just by packing them with Onyx."

AVMs are abnormal blood vessel networks that create unusually high blood flow between arteries and veins in the brain. That increased blood flow puts pressure imbalances on the malformed blood vessels, creating a risk for rupture leading to stroke, severe disability or death, he said.

AVMs are rare — one new case is diagnosed per year per 700 people, Cunningham said. He treats about 15 to 20 AVMs per year compared with about 80 brain aneurysms.

They're so rare that most people who've heard of AVM probably know it as the condition that killed 40-year-old Nate on the HBO series "Six Feet Under."

Unlike other brain disorders that tend to occur in people after age 55, AVMs are present from birth and tend to surface between ages 20 to 40. The first symptom may be a sudden headache, seizure or brain hemorrhage, he said.

Patients who choose not to treat the AVM have a 3 percent to 4 percent risk per year of bleeding at the site, Cunningham said. At that point there is a 10 percent chance of dying and a 20 percent chance of a stroke and permanent neurologic problems.

So the safer and more reliable an intervention like the Onyx system, the lower the risk for patients, he said.

"I think it revolutionizes how we can manage the AVMs," Cunningham added. "Even if we're not able to cure as many, it does allow us to do a better job of pre-operative flow reduction ... to reduce risk in surgery.

"But I think it will cure more down the road and be better for patients who do not have good options because of the natural history of the disease," Cunningham said.

Cunningham and a Cox South team performed the first Onyx procedure in the region, and the second one in the state after St. Louis. Cunningham is a vascular neurosurgeon who joined Springfield Neurological and Spine Institute in July 2005. SNI colleague Dr. Michael Workman, an interventional neuroradiologist, is also trained to do the procedure.

Dr. Matthew Burry, a neurosurgeon at St. John's Hospital in Springfield, is also using the Onyx treatment for AVMs, a spokeswoman said.

Onyx is made and distributed by Micro Therapeutics of Irvine, Calif., and was approved by the U.S. Food and Drug Administration in 2005. The company has been developing it since 1995 but European surgeons have been using it since 2002.

Cunningham is preparing to do two more procedures early this month after his first in April with Judith Nelson of Ozark.

SUDDEN HEADACHE

Nelson was attending a Christmas dinner Dec. 2, 2005, when she started coughing, got a sudden headache and lost vision in her right eye. By the time her husband got her to Cox South, she quit breathing and quick action saved her life.

An AVM had hemorrhaged near the part of her brain that controls sight. Doctors inserted a drain for the hemorrhage, and she spent 16 days in the intensive care unit. Weakened from the episode, Nelson underwent rehabilitation to regain strength and waited for treatment of the AVM.

Surgeons have long treated AVMs by opening the patient's skull and removing the abnormality if it's accessible. AVMs located too deep in the brain for surgery may be treated with radiosurgery, a focused radiation beam. But it may take up to three years to take effect and still be only 70 percent effective, Cunningham said.

AVMs bleed a lot during surgery, so doctors avoid that by first filling and blocking the lesion with a kind of glue, and later surgically removing the hardened AVM bundle.

The only way to deliver the glue to the site is through a catheter inserted at the groin and routed through blood vessels leading to the brain. Patients are asleep under general anesthesia and the surgeon watches the catheter's progress on an X-ray screen.

But the glue — which Cunningham calls "a distant cousin of Crazy Glue" — is a problem. It flows too slowly and dries too fast, making it hard to push enough glue into 100 percent of the lesion — necessary before surgery. Often doctors have to repeat the procedure, or risk gluing the catheter inside the patient's brain.

THE ONYX OPTION

Cunningham's experience treating Nelson with Onyx was far better.

Using the same steps with Onyx, Cunningham said the sealant glided easily through the catheter without sticking and allowed him to take his time filling the area. Once in place, the Onyx material transformed into a solid polymer cast, sealing off the vessels in the AVM from blood flow and reducing the risk of rupture in Nelson's brain.

Depending on the size of the affected area, a surgeon may release enough Onyx to fill the size of an acorn, a plum or the size of a golf ball, he said. The procedure can take one to two hours.

After Cunningham filled the AVM, he retracted the catheter back through the vessels and out the groin incision.

If the procedure had filled 100 percent of the space, Nelson could have avoided surgery, stayed several days for observation and gone home. A follow-up test showed the Onyx filled only 90 percent, so Cunningham surgically removed the AVM the next day. Nelson went home three days later.

Cunningham believes he and other surgeons across the country will be able to cure more AVMs without surgery as they get more experience using Onyx.

In the meantime, he said, "even if we can't cure them, Onyx reduces the risk of bleeding in surgery by 80 percent," making a serious operation safer for the patient.

Nelson accepted the odds. The possibility of avoiding surgery and a long recovery time using Onyx was worth a try, she said, and she's not disappointed.

"To me it was worth it," she said.

Today Nelson is working through the leftover partial "fog" in her vision, hoping it will clear as swelling subsides.

"I'm feeling good today, I walk at least a mile a day ... and hopefully I will find a job by July 4 and be back at work."

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