Utility and limitations of cortico-cortical evoked potentials in pediatric resective epilepsy surgery: illustrative...

The authors present the case of a 15-year-old male who underwent resection of a left parieto-occipital long-term epilepsy-associated tumor (LEAT) near the language and visual tracts. Tractography-guided dorsal language stream cortico-cortical evoked potentials (CCEPs) and visual evoked potentials (VEPs) were used intraoperatively under general anesthesia to minimize postoperative deficits. This case report describes the utility and limitations of CCEPs, VEPs, and tractography in pediatric resective epilepsy surgery.

During resection, CCEP N1 amplitude and latency remained stable; N2 latency was prolonged by 23% (from 11.3 to 14.0 msec). VEP P100 amplitude decreased transiently by approximately 80% intraoperatively and recovered to approximately 20% below baseline at closure. Postoperative MRI showed a subcortical ischemic infarct in the occipital periventricular white matter involving the inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, and optic radiations. Postoperatively, the patient exhibited dysphasia and right homonymous hemianopia. The patient remained seizure free with improved speech at the 18-month follow-up.

Intraoperative CCEPs, VEPs, and pre- and postoperative tractography have their uses and limitations in monitoring and assessing the integrity of language/visual white matter pathways. This case highlights underrecognized perforator-related subcortical infarction after LEAT resection and suggests a possible relationship between subcortical stroke and N2 latency changes that warrants further study. https://thejns.org/doi/10.3171/CASE25915.