Abstract
Objectives
Although hemispheric surgeries are among the most effective procedures for drug-resistant epilepsy (DRE) in the pediatric population, a large variability in outcomes remains. Identifying ideal hemispherectomy candidates is imperative to maximize the potential for seizure freedom. The objective was to develop an online, freely-accesible tool that accurately predicts the probability of seizure freedom for any patient at 1-, 2-, and 5-years post-hemispherectomy to provide clinicians accessible and reliable prognostic information to complement clinical judgement.
Methods
Retrospective data of all pediatric patients with DRE and seizure outcome data from the original Hemispherectomy Outcome Prediction Scale (HOPS) study were included. The primary outcome of interest was time-to-seizure recurrence. A multivariate Cox proportional-hazards regression model was developed to predict the likelihood of post-hemispheric surgery seizure freedom duration based on a combination of variables identified by clinical judgement and inferential statistics as predictive of the primary outcome. The final model from this study was encoded in a publicly accessible online calculator on the (iNEST) website.
Results
The selected variables for inclusion in the final model included the 5 original HOPS variables (age at seizure onset, etiologic substrate, seizure semiology, prior non-hemispheric resective surgery, and contralateral FDG-PET hypometabolism) and 3 additional variables (age at surgery, history of infantile spasms, and magnetic resonance (MR) imaging lesion). Predictors of shorter time-to-seizure recurrence included younger age at seizure onset, older age at surgery, prior resective surgery, generalized seizure semiology, FDG-PET hypometabolism contralateral to side of surgery, contralateral MR imaging lesion, non-lesional MR imaging, non-stroke etiologies, and history of infantile spasms. The area under the curve (AUC) of the final model was 73.0%.
Significance
Online calculators are efficient, cost-free tools that can facilitate physicians in risk-estimation and inform joint decision-making with families, potentially leading to greater satisfaction. Although the HOPS data was previously validated in the first analysis, the authors encourage prospective external validation of this new tool.
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