Temporal lobe surgery in medically refractory epilepsy: A comparison between populations based on MRI findings

AbstractIntroductionHigh resolution MRI findings suggestive of mesial temporal sclerosis (MRI-MTS) correlate with good outcome after surgery. However, a large group of patients present with normal brain MRI (N-MRI) and temporal lobe epilepsy (TLE). We aim to compare pre-operative ictal EEG patterns in predicting surgical outcomes in the population with MRI-MTS vs. N-MRI after selective anterior-mesial temporal lobe (AMTL) resection.Methods241 patients with unilateral anterior ictal EEG findings underwent selective AMTL resection. 143 MRI-MTS and 98 N-MRI patients were identified. Outcome was based on the modified Engel classification, ictal EEG pattern at seizure onset, demographics and MRI findings.ResultsSeizure-free outcome was seen in the MRI-MTS in 79% of patients, compared to 59.1% (p<.005) of the N-MRI group. No significant difference was identified in ictal EEG patterns at presentation between groups. Class I outcome was achieved in 78.9% of patients that had theta rhythm and MRI-MTS compared to 57.9% of patients that had theta rhythm and N-MRI (p