Long-Term Outcomes and Safety of Surgical Treatment Following Intracranial Electroencephalography Monitoring in Pediatric Epilepsy: A Single-Center Study.

OBJECTIVE: Intracranial electroencephalography (iEEG) monitoring presents additional challenges in pediatric patients compared to adults due to factors such as smaller body size, increased surgical invasiveness, difficulty maintaining rest, higher sensitivity to pain, and a greater risk of electrode self-removal. However, long-term outcomes and complications following resective surgery after iEEG evaluation in children remain underreported. This study aimed to evaluate the long-term outcomes and safety of surgical treatment following iEEG monitoring in pediatric patients.

METHODS: We retrospectively analyzed 24 pediatric patients (aged ≤15 years) who underwent surgical treatment after iEEG implantation between 1994 and 2024, with a minimum follow-up period of 5 years. Clinical characteristics, neuroimaging findings, details of iEEG monitoring, surgical procedures, epilepsy etiology, and seizure outcomes were reviewed.

RESULTS: The mean age at epilepsy onset was 4.5 years (range, 0.0-12.0), and the mean age at surgery was 10.4 years (range, 1.8-14.0). The average interval from seizure onset to surgery was 6.0 years (range, 0.9-14.8). The iEEG modalities included subdural grid electrodes alone (15 patients), a combination of subdural and depth electrodes (eight patients), and depth electrodes alone (one patient). The mean duration of iEEG monitoring was 9.1 days (range, 2-14). Surgical procedures included focal cortical resection and/or lesionectomy in 18 patients (75.0%), anterior temporal lobectomy in five (20.8%), and multiple subpial transections (MST) alone in one (4.2%). MST, in addition to resection, was performed in six patients (25.0%). Thirteen patients (54.2%) achieved Engel class I or II outcomes. No perioperative complications related to iEEG implantation occurred, and no patients experienced permanent neurological deterioration. Blood transfusion was not required in any case. MEG-MRI (magnetoencephalography-magnetic resonance imaging) concordance was significantly associated with favorable seizure outcomes.

CONCLUSION: This study demonstrated a good seizure outcome rate of 54.2% in pediatric patients who underwent surgical treatment following iEEG monitoring. No major perioperative complications related to iEEG implantation were observed, and no patients experienced permanent neurological deterioration in this cohort. These findings suggest that with careful electrode selection, precise placement and fixation, and vigilant perioperative management, iEEG can be safely performed even in very young children. Furthermore, the presence of MEG clusters concordant with MRI lesions tended to be associated with better seizure outcomes after resection, suggesting a possible role of multimodal imaging data in individualized treatment planning.