Long-term surgical outcomes and predictors of surgical treatment in temporal lobe epilepsy

Background: Surgical treatment of epilepsy is a favored modality in the management of refractory temporal lobe epilepsy (TLE) and known to be quite effective. The aim of this study was to evaluate the long-term outcomes in surgical treatment of TLE and to identify prognostic factors influencing postoperative seizure remission. Materials and Methods: The patients who underwent anterior temporal lobectomy (ATL) with the diagnosis of refractory TLE in our center between the years of 2006 and 2020 were included. Preoperative workup process was carried out by a multidisciplinary team and consisted of neuropsychological examination, long-term electroencephalography, brain magnetic resonance imaging (MRI), and fluorodeoxyglucose positron emission tomography (FDG-PET) for each patient. Postoperative assessment of seizure control was repeated every year following surgery and categorized according to Engel's outcome classification. The predictive value of baseline demographic, clinical, laboratory, imaging, and histopathological parameters on postoperative seizure control was also evaluated. Results: One hundred and forty-three patients who underwent ATL with the diagnosis of TLE were included. According to Engel's classification, the seizure freedom rate was found to be 83.2% at the 2nd year, 81.3% at the 4th year, and 79.2% at the 10th year after surgery. In the univariate analysis, febrile seizure (FS) history, unilateral interictal epileptiform discharges (IEDs), hippocampal sclerosis (HS) on MRI, unilateral temporal hypometabolism (HM) on FDG-PET, and HS in histopathology were predictors of seizure control at the postoperative 2nd and 10th years. FS history, unilateral localization of IEDs, and unilateral FDG-PET findings of temporal HM were found to be the independent predictors of postoperative seizure control on multivariate analysis. Conclusions: In the current study, we revealed that epilepsy surgery provides effective seizure control and represents a beneficial therapeutic option in refractory TLE. Our results also suggested that FS history, unilateral IEDs, and unilateral FDG-PET findings of temporal HM were independent predictors of seizure remission in these patients.