The role of brain magnetic resonance imaging on the timing of antiepileptic drugs withdrawal following mesial temporal lobe epilepsy surgery

Abstract

Objectives: To assess the influence of magnetic resonance imaging (MRI) brain findings on the timing of antiepileptic drugs (AEDs) withdrawal following anterior temporal lobectomy (ATL) in patients with mesial temporal lobe epilepsy (MTLE). Methods: We conducted a retrospective chart review at King Faisal Specialist Hospital and Research Centre, Jeddah, Saudi Arabia from Jan, 2004 – Dec, 2017 of patients with MTLE who underwent ATL and included patients who had a minimum of 2 years of follow-up. We evaluated the association between the time required to start tapering and discontinuing AEDs after ATL in patients with Engel class I outcomes and their preoperative brain MRI. Results: We studied 64 patients who underwent ATL. The majority of patients (63%) had hippocampal sclerosis (HS) on histopathology. Following ATL, the mean time to start tapering AEDs was 10 months and AEDs were discontinued at a mean of 48 months. Abnormal brain MRI was observed in 53 (83%) patients, with findings suggestive of mesial temporal sclerosis (MTS) accounting for 75% of these abnormalities. The presence of any MRI abnormality was associated with a 10-month earlier tapering of AEDs (p<0.01), and an 18-month earlier complete withdrawal of AEDs (p<0.01). The odds of being seizure-free within the first year were higher if MTS was present in the brain MRI (adjusted OR=16). Similarly, this was associated with seizure freedom after the first year (adjusted OR=14.8, p<0.01). The presence of unilateral temporal IEDs on preoperative EEG were also associated with earlier tapering and discontinuation of AEDs as well as a seizure-free state after ATL surgery (OR=8.5 and 4.2, for the first and second year respectively, p<0.01). Conclusion: Patients with abnormal MRI findings and unilateral IEDs had earlier tapering of AEDs with an overall shorter AED discontinuation plan. Moreover, the presence of MTS on MRI, along with unilateral IEDs, were predictors of seizure freedom following ATL.