Schmeiser B, et al. - This investigation was performed to examine the role of presurgical EEG parameters and of reoperation for seizure outcome in temporal lobe epilepsy. For seizure outcome, preoperative bilateral ictal foci were a negative predictor. On the other hand, interictal epileptiform discharges (IED) exceeding the affected temporal lobe in the ipsilateral hemisphere or even bilateral IED had favorable seizure outcome if seizure onset was strictly limited to the affected temporal lobe. Reoperation for seizure persistence constituted a promising therapeutic option.

• The authors included 426 consecutive patients operated for intractable mTLE.
• They examined impact of preoperative seizure onset and IED on the persistence of seizures and results of reoperation.

• 27% of patients with mTLE experienced persistent seizures (Engel II–IV) 1 year after surgery.
• In EEG, preoperative bilateral seizure onset was predictive for postoperative seizure recurrence (Engel II–IV: 64%).
• Compared to patients with seizure foci confined to the ipsilateral temporal lobe (Engel I: 75% and 76%), seizure foci and IED exceeding the temporal lobe in the ipsilateral hemisphere were not found to be correlated with worse seizure outcome (Engel I: 72% and 75%).
• Furthermore, if seizure onset was strictly limited to the affected temporal lobe, IED exceeding the affected temporal lobe in the ipsilateral hemisphere or even bilateral IED did not negatively affect seizure freedom (Engel I: 85% and 65%, respectively).
• As per the outcomes, 60% of patients reoperated in the ipsilateral temporal lobe for persistent seizures became seizure free.