Patients are benefiting from new surgical technologies at Cincinnati Children’s that push the boundaries of what is possible in the treatment of brain tumors, intractable epilepsy and dystonia. Cincinnati Children’s is one of only a few pediatric institutions in the country to offer a robotic-assisted stereotactic system, stereoelectroencephalography and next-generation intraoperative magnetic resonance imaging (MRI) with laser ablation. These can be used in combination for a wide variety of interventions.

For example, robotic-assisted surgery and stereo EEG can be used together to localize seizure onset zones and, in some cases, ablate diseased tissue. “The robotic arm holds needle-thin tools that we can use to make three-millimeter burr holes in the skull for electrode placement,” says Francesco Mangano, DO, chief of pediatric neurosurgery at Cincinnati Children’s. “With the help of stereo EEG, we can place electrodes deep in the brain, not just on the lateral surface. This improves our accuracy in mapping the seizure focus, and allows us to obtain information about different regions of the brain in a way that was not possible with subdural grid placement alone.

“After EEG monitoring is complete, we can send the patient home and take time to create an optimal surgical plan,” Mangano adds. “We may be able to destroy diseased tissue or brain tumors deep in the brain using laser ablation, rather than with conventional invasive surgical resection. If ablation is not successful, however, patients can still pursue surgical resection.”

A recent case demonstrates the power and precision of this advanced technology. The female patient developed intractable seizures at the age of 15, and over the course of three years took eight seizure-control medications that caused significant side effects while failing to provide relief. In November 2016, she became one of the first patients at Cincinnati Children’s to benefit from the robotic surgical system and stereo EEG. Mangano placed 15 depth electrodes, and localized the seizure focus to two contacts on one electrode, in the posterior cingulate cortex. A week later, the patient returned to the operating room, where Mangano advanced a laser ablation catheter through an existing burr hole and destroyed the diseased tissue. The patient returned home the next day and has been seizure-free ever since.

Pinpoint precision 

Robotic-assisted placement of leads is used to help children with medically intractable dystonia who may benefit from deep brain stimulation (DBS). In adults with dystonia, the neurosurgeon uses stereotactic guidance to implant the device, and then awakens the patient during surgery to see whether symptoms have subsided. This is not feasible in pediatric patients, especially those with developmental disabilities, who represent a large percentage of children with dystonia. Cincinnati Children’s pediatric neurosurgeon Sudhakar Vadivelu, DO, offers an alternative approach that allows the patient to be asleep throughout the procedure.

The surgery takes place in the bore of the intraoperative magnet. Using an MR-compatible head frame and surgical system, Vadivelu guides a fiber-sized wire into the deep structures of the brain and implants the electrode into the globus pallidus or, less commonly, the subthalamic nucleus. “MRI guidance means we can navigate toward the target and be absolutely sure that we’ve hit it,” says Vadivelu, the only fellowship-trained pediatric neurosurgeon in the country wholly dedicated to providing open and endovascular surgical techniques for children with cerebrovascular disease. “We are able to achieve sub-millimeter accuracy, even if the brain shifts during surgery.”

Within a few weeks of the DBS electrode placement, the patient returns to the hospital for an outpatient procedure to implant a pulse generator in the chest. Steven Wu, MD, a pediatric neurologist and director of the Dystonia and Surgical Movement Disorder Clinic, programs the technology and can make adjustments to voltage, stimulation frequency and other settings as needed.

“We have used DBS to treat patients with dystonia 1, dystonia 6, secondary dystonia related to stroke, Lesch-Nyhan disease and other conditions,” says Wu. “Outcomes depend largely on the patient’s underlying etiology, but everyone we have treated with DBS has experienced improvement. For some, this has meant functional improvement in gait; for others, the improvement is more about impacting quality of life through better sleep or decreased daytime tremors.”