Comparison of the real‐world effectiveness of vertical versus lateral functional hemispherotomy techniques for pediatric drug‐resistant epilepsy: A post hoc analysis of the HOPS study
Authors: Fallah Aria , Lewis Evan , Ibrahim George M. , Kola Olivia , Tseng Chi‐Hong , Harris William B. , Chen Jia‐Shu , Lin Kao‐Min , Cai Li‐Xin , Liu Qing‐Zhu , Lin Jiu‐Luan , Zhou Wen‐Jing , Mathern Gary W. , Smyth Matthew D. , O'Neill Brent R. , Dudley Roy W. R. , Ragheb John , Bhatia Sanjiv , Delev Daniel , Ramantani Georgia , Zentner Josef , Wang Anthony C. , Dorfer Christian , Feucht Martha , Czech Thomas , Bollo Robert J. , Issabekov Galymzhan , Zhu Hongwei , Connolly Mary , Steinbok Paul , Zhang Jian‐Guo , Zhang Kai , Hidalgo Eveline Teresa , Weiner Howard L. , Wong‐Kisiel Lily , Lapalme‐Remis Samuel , Tripathi Manjari , Sarat Chandra Poodipedi , Hader Walter , Wang Feng‐Peng , Yao Yi , Champagne Pierre‐Olivier , Brunette‐Clément Tristan , Guo Qiang , Li Shao‐Chun , Budke Marcelo , Pérez‐Jiménez Maria Angeles , Raftopoulos Christian , Finet Patrice , Michel Pauline , Schaller Karl , Stienen Martin N. , Baro Valentina , Cantillano Malone Christian , Pociecha Juan , Chamorro Noelia , Muro Valeria L. , von Lehe Marec , Vieker Silvia , Oluigbo Chima , Gaillard William D. , Al‐Khateeb Mashael , Al Otaibi Faisal , Krayenbühl Niklaus , Bolton Jeffrey , Pearl Phillip L. , Weil Alexander G. 
Published: September 2021

Objective

This study was undertaken to determine whether the vertical parasagittal approach or the lateral peri‐insular/peri‐Sylvian approach to hemispheric surgery is the superior technique in achieving long‐term seizure freedom.

Methods

We conducted a post hoc subgroup analysis of the HOPS (Hemispheric Surgery Outcome Prediction Scale) study, an international, multicenter, retrospective cohort study that identified predictors of seizure freedom through logistic regression modeling. Only patients undergoing vertical parasagittal, lateral peri‐insular/peri‐Sylvian, or lateral trans‐Sylvian hemispherotomy were included in this post hoc analysis. Differences in seizure freedom rates were assessed using a time‐to‐event method and calculated using the Kaplan–Meier survival method.

Results

Data for 672 participants across 23 centers were collected on the specific hemispherotomy approach. Of these, 72 (10.7%) underwent vertical parasagittal hemispherotomy and 600 (89.3%) underwent lateral peri‐insular/peri‐Sylvian or trans‐Sylvian hemispherotomy. Seizure freedom was obtained in 62.4% (95% confidence interval [CI] = 53.5%–70.2%) of the entire cohort at 10‐year follow‐up. Seizure freedom was 88.8% (95% CI = 78.9%–94.3%) at 1‐year follow‐up and persisted at 85.5% (95% CI = 74.7%–92.0%) across 5‐ and 10‐year follow‐up in the vertical subgroup. In contrast, seizure freedom decreased from 89.2% (95% CI = 86.3%–91.5%) at 1‐year to 72.1% (95% CI = 66.9%–76.7%) at 5‐year to 57.2% (95% CI = 46.6%–66.4%) at 10‐year follow‐up for the lateral subgroup. Log‐rank test found that vertical hemispherotomy was associated with durable seizure‐free progression compared to the lateral approach (p = .01). Patients undergoing the lateral hemispherotomy technique had a shorter time‐to‐seizure recurrence (hazard ratio = 2.56, 95% CI = 1.08–6.04, p = .03) and increased seizure recurrence odds (odds ratio = 3.67, 95% CI = 1.05–12.86, p = .04) compared to those undergoing the vertical hemispherotomy technique.

Significance

This pilot study demonstrated more durable seizure freedom of the vertical technique compared to lateral hemispherotomy techniques. Further studies, such as prospective expertise‐based observational studies or a randomized clinical trial, are required to determine whether a vertical approach to hemispheric surgery provides superior long‐term seizure outcomes.