Favorable seizure and developmental outcomes without preoperative intracranial electroencephalography in pediatric patients following epilepsy surgery: A single epilepsy center retrospective study

Abstract

Objective: At our institute, most pediatric patients undergo epilepsy surgery following a thorough presurgical evaluation without intracranial electroencephalography (EEG). We conducted an initial validation of our noninvasive presurgical strategy by assessing the seizure and developmental outcomes of 135 children. Methods: All 135 pediatric patients were <15 years old, had undergone curative surgery, and were followed for at least 2 years postoperatively. Presurgical evaluations and postoperative seizure and developmental outcomes were investigated. Thorough noninvasive evaluation included 3-T magnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography (FDG-PET) in all patients. Intracranial EEG was mainly indicated for patients whose MRIs were negative or subtle. We defined Engel class I as favorable and Engel classes II–IV as unfavorable seizure outcomes. Intelligence quotient (IQ) and developmental quotient (DQ) before and 2 years after surgery were used to assess developmental/neuropsychological outcomes. Results: MRI was positive in 130 of 135 patients (96.3%), including 39 of 40 with focal cortical dysplasia (FCD) type II and 30 of 33 with FCD type I. FDG-PET revealed concordant localizing findings in 119 of 132 patients (90.2%). Ictal single photon emission computed tomography provided concordant localizing information in 85 of 91 patients (93.4%). Intracranial EEG was performed in only 10 of 135 patients (7.4%). Ninety-seven of 135 patients (71.9%) were seizure-free 2 years after surgery. The final seizure-free rate was 99 of 135 (73.3%). Temporal lobe surgery predicted a favorable seizure outcome by multivariate analysis, whereas FCD type I and preoperative IQ/DQ < 70 predicted an unfavorable outcome. The mean IQ change was +1.3 points, and the mean DQ change was +1.0 points. Mean DQ significantly improved following extratemporal surgery (multivariate regression, p