Seizure outcome of pediatric epilepsy surgery: systematic review and meta-analyses

Objective: This systematic review and meta-analyses assessed seizure outcome following pediatric epilepsy surgery.

Methods: MEDLINE, Embase and Cochrane were searched for pediatric epilepsy surgery original research from 1990 to 2017. The outcome was seizure freedom at 12 months or longer follow-up. Using random effects models, the effect sizes for controlled studies, uncontrolled studies on surgery locations (temporal lobe [TL], extra-temporal lobe [ETL] or hemispheric surgery), pathologies, non-lesional epilepsy and incomplete resection were estimated. Meta-regression assessed the relationship between age at surgery, age at seizure onset and seizure outcome. Random-effects network meta-analysis was conducted for surgery locations.

Results: 258 studies were included. Surgery achieved higher seizure freedom than medical therapy (OR=6.49 [95%CI: 2.87, 14.70], p<0.001). Seizure freedom declined over time after surgery, from 64.8% (95%CI: 51.2%, 76.4%; p=0.034) at 1 year, to 60.3% (95%CI: 52.9%, 67.4%; p=0.007) at 5 years, and 39.7% (95%CI: 28.4%, 52.2%, p=0.106) at 10 years. Seizure freedom was (i) highest for hemispheric surgery, followed by TL, and ETL surgery; and (ii) highest for tumor, and lower for malformations of cortical development. Seizure freedom was lower for non-lesional than lesional epilepsy (OR=0.54 [95%CI: 0.34, 0.88], p=0.013), and incomplete than complete resection (OR=0.13 [95%CI: 0.08, 0.21], p<0.001). Age at surgery and age at seizure onset were associated with seizure freedom for mixed pathologies and surgery locations, and TL surgery.

Conclusion: Epilepsy surgery was more effective than medical therapy to control seizures. Understanding seizure outcomes of different surgery locations, pathologies, non-lesional epilepsy and incomplete resection will assist with pre-surgical counselling.