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 < .05), and mean DQ significantly decreased in patients with epileptic spasms (multivariate regression, p < .01).

Significance: Thorough noninvasive presurgical evaluation enables detection of subtle MRI lesions and curative epilepsy surgery without intracranial EEG in most patients, including those with FCD type II and type I, and leads to favorable seizure and developmental/neuropsychological outcomes.