231 Postoperative Seizure Outcome of a Cohort of Patients With Drug Resistant Epilepsy and Malformations of Cortical Development Selected Predominantly by Non-invasive Evaluation

Abstract

INTRODUCTION: Optimizing the surgical outcome of people with drug-resistant epilepsy (DRE) and malformations of cortical development (MCD) can be quite challenging. The studies are limited in this regard, especially from the low and middle income countries (LAMIC). METHODS: Between April, 2011 and March, 2023, 584 people with drug resistant epilepsy underwent surgery at NIMHANS, Bangalore, India. MCD as an underlying substrate have been identified among 170 patients. Different types of MCD, their pre-surgical evaluation, surgical strategy and outcome predictors have been studied. RESULTS: Cohort consists of 170 people with a mean age at surgery of 17.01 ± 10.94 (range 1.2 – 60) years. Mean age at seizure onset of 7.45 ± 7.39 (range 1 month to 40) years. The mean duration of epilepsy before surgery of 9.17 ± 7.58 (range 1-32) years. Males constituted 62.35% of patients (n= 106). Mean seizure score of the cohort was at 8.61 ± 1.34 (range 4-12 on a scale of 0 -12). Lifetime drugs tried by the cohort ranged from 1- 6 with mean of 2.85 ± 0.95. FCD was noted in 120 patients (70.587%). At a mean follow up of 4.66 ± 2.80 years, cohort had an Engel outcome class Ia, I, II, III and IV of 71.1%, 83.6%, 3.1%, 7.80% and 5.5 % respectively. Range of current AEDs used by the cohort is nil to 5, with mean of 2.28 ± 1.41. CONCLUSIONS: In this study, three variables were found to influence the outcome towards favourable arm of Engel class Ia. These factors are histopathology of FCD with balloon cells, glioneuronal aetiology and an age of less than 18 years at the time of surgery.