Everything about the youngster’s brain tumor tied the hands of Ramin Eskandari, M.D., Assistant Professor of Neurosurgery at MUSC Health. It was located near the basal ganglia and the thalamus, areas deep within the brain that are hard to reach and packed with the neurons that control critical functions, such as movement, sensory relay, temperature regulation, and sleep/wake cycles. The tumor was growing quickly, but surgery to remove it was out of the question given the damage that surgery would likely do to such high-priced real estate. That left radiation, but the patient was nine years old, too young for the inevitable brain damage of radiation. Eskandari needed to buy some time while her brain developed. He didn’t have it.
“So we asked ourselves what are the ways we can hold off the tumor a little,” says Eskandari. “That’s when this new laser became an option.”
Laser interstitial thermal therapy has been used for years to ablate brain tumors, but certain technical factors made the traditional technology less than ideal in this case. The advanced technology of a new tool, the NeuroBlate System™ (Monteris Medical Inc., Plymouth, MN), brought benefits that gave Eskandari a viable option for his patient. Fixation of the probe entry device on the head is less susceptible to shifting, the laser has a 350 degree firing range (as opposed to only straight ahead), and thermal damage to surrounding tissue is more precisely controlled. But even the solution had its downsides.
There have not been very many cases of pediatric brain tumors ablated with lasers in the U.S. In researching those few, Eskandari could not find a single laser ablation procedure that was performed in this location in the brain. The procedure would be a first for Eskandari, for the hospital, and for the state. It would be risky for the patient. She faced possible weakness or numbness afterward, difficulty swallowing, and Eskandari could not say how long that might last. “All I knew was this was a much less invasive option than surgery, which would definitely cause more damage,” he says.
After presenting the case to the hospital’s tumor board and oncologists, discussing previous cases with the manufacturer, and consulting with the family, Eskandari decided to use the NeuroBlate system. On May 15, the child was placed in a magnetic resonance imaging (MRI) machine that sent images to Eskandari in a control room where he was guided by the yellow and green outlines of the heat so he could avoid damaging healthy tissue. Afterward, he was prepared for the worst.
In the recovery room, the patient had weakness on her left side for about three hours. She went home without symptoms 18 hours later. If in three months when surgical swelling is gone, Eskandari sees any reduction in tumor volume plus continued normal function, he will feel that the procedure was a success. “Tumor-wise, we’ll see,” he says. “But even if the tumor shrinks 50%, that will give her years off of getting radiation. The best case scenario is radiation kills the rest of it and we just monitor her for the rest of her life.”
This system, as well as other MRI-guided laser systems, e.g., Visualase® (Medtronic, Inc., Minneapolis, MN), also benefit epilepsy patients, whose seizures often originate with lesions deep within the brain. William A. Vandergrift, M.D., Associate Professor of Neurosurgery at MUSC Health, has treated two epilepsy patients with NeuroBlate and three with Visualase. For more information on one of his Visualase procedures, visit http://academicdepartments.musc.edu/catalyst/archives/2015/7-17Visualase.html.