Neurologists also have become more comfortable with invasive EEG monitoring in children with challenging epilepsies. Epilepsy centers each have a different level of comfort with this monitoring, said Dr. Weiner. Some neurologists have used the monitoring for children with nonconcordant and nonlocalizing MRI. A more controversial application would be for determining which of multiple lesions is the epileptic focus in a child. Invasive EEG monitoring also could help define the relationship of the focus to a structural lesion on MRI.
In addition, neurologists have become more willing to consider aggressive surgical resections, even if they are likely to result in neurologic deficits. “Epilepsy surgery is a quality-of-life intervention, and we’re trading off a potential physical deficit like a visual field cut or a mild hemiparesis for the idea of seizure freedom and developmental improvement,” said Dr. Weiner. “This point is unique to pediatric medicine, where the mandate to act for us is much stronger when the potential impact we can have, with respect to the child’s development, may be lifelong.”
Rates of Postsurgical Seizure Freedom May Decline Over Time
When considering surgery as a treatment option, neurologists must consider what the procedure’s long-term efficacy is likely to be. Researchers at the Cleveland Clinic examined data for all the patients that they had studied with intracranial electrodes. They found that the rate of seizure freedom decreased with time. At two years after surgery, approximately two-thirds of patients were seizure free. The rate of seizure freedom was 50% at five years and approximately 40% at 10 years.
The investigators hypothesized that early postresection failures may result from incomplete resections or from missing the focus. Later failures may result from “yet-unknown mechanisms, including the presence of more extensive but dormant proepileptic cortex,” said Dr. Weiner. “We have to be well aware of [this issue] as we’re taking on some of these more challenging and diffuse pathologies. You have to discuss this with the families.
“Although the spectrum of epilepsy surgery in children appears to be expanding, we absolutely need to exercise great caution in approaching all these cases, and our default presumption should be one of reluctance” to perform surgery, said Dr. Weiner.
Surgery in young children is potentially dangerous, and many children will require intracranial studies that may be too invasive, he noted. For certain children, surgery may not yield a better long-term outcome than medical therapy. And extensive evaluation and treatment in a hospital can be cost-prohibitive.
“These children are best evaluated at comprehensive epilepsy centers where the risk–benefit analysis can be determined collectively by the treating team after an extensive evaluation,” Dr. Weiner concluded.
—Erik Greb