Development of an online calculator for the prediction of seizure freedom following pediatric hemispherectomy using the Hemispherectomy Outcome Prediction Scale (HOPS)
Alexander G. Weil, Evan Dimentberg, Evan Lewis, George M. Ibrahim, Olivia Kola, Chi‐Hong Tseng, Jia‐Shu Chen, Kao‐Min Lin, Lixin Cai, Qingzhu Liu, Jiuluan Lin, Wenjing Zhou, Gary W. Mathern, Matthew D. Smyth, Brent R. O’Neill, Roy Dudley, John Ragheb, Sanjiv Bhatia, Daniel Delev, Georgia Ramantani, Josef Zentner, Anthony Wang, Christian Dorfer, Martha Feucht, Thomas Czech, Robert J. Bollo, Galymzhan Issabekov, Hongwei Zhu, Mary Connolly, Paul Steinbok, Jianguo Zhang, Kai Zhang, Eveline Teresa Hidalgo, Howard L. Weiner, Lily C. Wong‐Kisiel, Samuel Lapalme‐Remis, Manjari Tripathi, Poodipedi Sarat Chandra, Walter Hader, Feng‐Peng Wang, Yi Yao, Pierre Olivier Champagne, Tristan Brunette‐Clément, Qiang Guo, Shao‐Chun Li, Marcelo Budke, María Ángeles Pérez-Jiménez, Christian Raftopoulos, Patrice Finet, Pauline Michel, Karl Schaller, Martin N. Stienen, Valentina Baro, Christian Cantillano Malone, Juan Pociecha, Noelia Chamorro, Valeria L. Muro, Marec von Lehe, Silvia Vieker, Chima Oluigbo, William D. Gaillard, Mashael Al Khateeb, Faisal Alotaibi, Niklaus Krayenbühl, Jeffrey Bolton, Phillip L. Pearl, Aria Fallah
Abstract
OBJECTIVES: Although hemispheric surgeries are among the most effective procedures for drug-resistant epilepsy (DRE) in the pediatric population, there is a large variability in seizure outcomes at the group level. A recently developed HOPS score provides individualized estimation of likelihood of seizure freedom to complement clinical judgement. The objective of this study was to develop a freely accessible online calculator that accurately predicts the probability of seizure freedom for any patient at 1-, 2-, and 5-years post-hemispherectomy. 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 at three time points (1-, 2- and 5- years) based on a combination of variables identified by clinical judgment and inferential statistics predictive of the primary outcome. The final model from this study was encoded in a publicly accessible online calculator on the International Network for Epilepsy Surgery and Treatment (iNEST) website (https://hops-calculator.com/). RESULTS: The selected variables for inclusion in the final model included the five original HOPS variables (age at seizure onset, etiologic substrate, seizure semiology, prior non-hemispheric resective surgery, and contralateral fluorodeoxyglucose-positron emission tomography [FDG-PET] hypometabolism) and three additional variables (age at surgery, history of infantile spasms, and magnetic resonance imaging [MRI] lesion). Predictors of shorter time-to-seizure recurrence included younger age at seizure onset, prior resective surgery, generalized seizure semiology, FDG-PET hypometabolism contralateral to the side of surgery, contralateral MRI lesion, non-lesional MRI, non-stroke etiologies, and a history of infantile spasms. The area under the curve (AUC) of the final model was 73.0%. SIGNIFICANCE: Online calculators are useful, cost-free tools that can assist physicians in risk estimation and inform joint decision-making processes with patients and families, potentially leading to greater satisfaction. Although the HOPS data was validated in the original analysis, the authors encourage external validation of this new calculator.