Postresection Monitoring May Provide Further Insights on Epileptogenic Zone Following Multistage Epilepsy Surgery

Postresection monitoring (PRM) after multistaged epilepsy surgery in children may provide additional information on the extent of the epileptogenic zone, including residual epileptogenic activity at the margins of the resection cavity, and may reveal additional seizure foci. A retrospective chart review of pediatric patients with neocortical epilepsy who underwent resective surgery with PRM in the Division of Pediatric Neurosurgery, New York University Langone Health, New York City, between January 2001 and December 2014 was conducted, with the results published in Epilepsy Research.

The investigators sought to report on the technique and outcomes experienced among children with epilepsy who were treated with staged surgery, including PRM. A total of 71 patients were evaluated: 5 with magnetic resonance imaging (MRI)-negative epilepsy and 66 with MRI-identified neocortical lesions. Overall, 97% (64 of 66) of patients with MRI-identified neocortical lesions underwent complete lesionectomy.

Among 86% (61 of 71) of the patients assessed, the use of PRM was associated with positive outcomes. The findings among these children included clinical seizures with electrographic involvement at resection margins in 47%, subclinical seizures and interictal discharges at resection margins in 29%, and clinical and subclinical seizures that revealed a new epileptogenic focus in 20%.

Among 78% (55 of 71) of the patients, PRM data led to additional resection (ie, re-resection). Moreover, 6 additional children did not undergo further resection because of overlap with the eloquent cortex. Histopathology revealed tuberous sclerosis complex in 46 patients, focal cortical dysplasia in 16 patients, gliosis in 4 patients, tumors in 4 patients, and Sturge-Weber syndrome in 1 patient.

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No major complications were reported among the children. In patients with tuberous sclerosis complex, seizure-free outcome was 63% at 1-year follow-up and 56% at 2-year follow-up. In patients with focal cortical dysplasia, seizure freedom after 1 and 2 years was 85%.

The investigators concluded that the use of re-resection after monitoring can increase the likelihood of attaining long-term stable seizure-free outcomes in selected individuals. The approach may be particularly useful in such complex cases as individuals with multiple lesions, nonlateral or discordant radiologic or electrographic findings, and additional seizure onset activity outside the lesion on presurgical monitoring and in patients with tuberous sclerosis complex with early-onset seizures.


Hidalgo ET, Frankel HG, Rodriguez C, et al. Invasive monitoring after resection of epileptogenic neocortical lesions in multistaged epilepsy surgery in children. Epilepsy Res. 2018;148:48-54.