Surgery for Drug Resistant Epilepsy with Malformations of Cortical Development: Role of Non-Invasive Pre-Surgical Evaluation, Surgical Strategy and Seizure Outcome Prediction.

Abstract

Objective: Selecting patients for surgery for drug resistant epilepsy (DRE) with malformations of cortical development (MCD) by non-invasive evaluation is challenging. Optimizing surgical strategy and predicting seizure outcomes are also difficult. We analyzed the data of patients with DRE and MCD over a 12-year period at a single institution to assess the role of non-invasive pre-surgical evaluation, surgical strategy, and predictors of seizure outcome.

Methods: Between April 2011 and March 2022, 584 patients with DRE underwent pre-surgical evaluation and surgery at our institution. During the study period, a total of 93 patients underwent surgery for DRE and MCD. Six patients who underwent invasive evaluation, and another six patients with incomplete data were excluded from the study. We have analyzed the clinical profile, pre-surgical evaluation data, surgical strategy, histopathology, and seizure outcome and have identified the predictors of the seizure outcome.

Results: The cohort consists of 81 patients (males = 47) with a mean age of seizure onset of 6.85 years and mean age at surgery of 16.54 years. The mean duration of epilepsy before surgery was 9.75 years. The mean follow-up period was 8.66 years. In this study, 63 patients achieved international league against epilepsy (ILAE) class 1 outcome and 18 patients achieved class 2-6 outcome. Of the patients who had complete resection of the lesion, 86.2% had ILAE class 1 outcome, and those with incomplete resection had 55.17%. We found that factors such as fewer anti-seizure medications and complete resection of the lesion were associated with a favorable outcome on multivariable analysis.

Conclusions: Based upon these predictors, we conclude that patients with stereotypical habitual seizures, who were on fewer anti seizure medications (ASM) preoperatively and who have undergone complete resection of the lesion can expect a favorable post-operative seizure outcome. Lack of concordant findings on pre-surgical evaluation did not independently predict poor outcome in this study, suggesting that discordant findings should not per se exclude patients with MCD from undergoing epilepsy surgery.