Radical surgery has lasting benefits for epileptic children

By Eleanor McDermid, Senior medwireNews Reporter

Hemispherectomy in children with medically refractory epilepsy offers a high rate of long-term seizure control, report US researchers.

Two-thirds of children who underwent the procedure were seizure-free around 5 years later, say Ajay Gupta and colleagues from the Cleveland Clinic in Ohio. And a substantial proportion of those with seizure recurrence had a major improvement from baseline, they report in Neurology.

In an accompanying editorial, Samuel Wiebe (University of Calgary, Alberta, Canada) and Anne Berg (Northwestern Feinberg School of Medicine, Chicago, Illinois, USA) say: "Because hemispherectomy is often performed in children who already have moderate to severe hemiplegia, the added motor deficits from the surgery are generally low.

"Furthermore, given the plasticity in the developing brain, surgery when done early may allow reorganization and preservation of both motor and cognitive function."

But they stress that "we are still lacking a comprehensive assessment of developmental, cognitive, and other functional outcomes in the children, and the global positive or negative effects on their lives and on their families."

The 170 children in the study were 7 years old, on average, when they underwent hemispherectomy. An average of 5.3 years later, 66% of the children had remained consistently seizure-free from 7 days after surgery.

Among the other children, 5% (of the whole cohort) had late remission, 9% had more than 90% improvement in seizure intensity and frequency, and 6% had 50-90% improvement. A further 3% had a less than 50% improvement, 4% had no improvement, and seizure burden was unknown in the remaining 6%.

Overall, 80% of children achieved complete freedom from seizures or a major improvement, say Gupta et al.

The team found two factors that independently predicted seizure recurrence after accounting for multiple confounders. These were the presence of bilateral abnormalities on positron emission tomography, which raised recurrence risk 2.53-fold, and having seizures within 7 days of hemispherectomy, which raised the risk 7.03-fold. Just 29% of patients with both these factors achieved freedom from seizures.

Twenty-three children in the study were undergoing hemispherectomy for the second time. This proved curative in eight (35%) suggesting surgical failure of the first procedure. However, persistent seizures in the other 65% implied intrinsic epileptogenicity in the other hemisphere.

"Hence, while evaluating candidates for hemispherectomy, the emphasis should include analysis of the abnormalities in the opposite hemisphere that may indicate independent epileptogenicity," say the researchers.

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