The role of presurgical EEG parameters and of reoperation for seizure outcome in temporal lobe epilepsy

• Published in: Seizure (London, England) Vol. 51; pp. 174 - 179
• Main Authors: Schmeiser, B., Zentner, J., Steinhoff, B.J., Brandt, A., Schulze-Bonhage, A., Kogias, E., Hammen, T.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2017
• Subjects: Adolescent; Adult; Aged; Bilateral seizure focus; Child; Child, Preschool; Electroencephalography - methods; Epilepsy surgery; Epilepsy, Temporal Lobe - complications; Epilepsy, Temporal Lobe - physiopathology; Epilepsy, Temporal Lobe - surgery; Female; Humans; Intractable mesiotemporal lobe epilepsy; Male; Middle Aged; Recurrence; Reoperation; Retrospective Studies; Seizure recurrence; Seizures - etiology; Seizures - physiopathology; Seizures - surgery; Young Adult; Reoperation; Seizure recurrence; Epilepsy surgery; Bilateral seizure focus; Intractable mesiotemporal lobe epilepsy
• ISSN: 1059-1311; 1532-2688
• DOI: 10.1016/j.seizure.2017.08.015

•Preoperative bilateral seizure onset predicts postoperative seizure recurrence.•Seizure freedom is possible if epileptic zone exceeds affected temporal lobe ipsilaterally or is bilateral if seizure onset is limited.•Reoperation for seizure persistence is a promising therapeutic option. After surgery for intractable mesiotemporal lobe epilepsy (mTLE) seizures recur in 30–40%. One predictor for seizure recurrence is the distribution of seizure onset and interictal epileptiform discharges (IED). Our study focused on lateralization and extent of epileptiform activity regarding postoperative seizure persistence and the effect of reoperation. This study comprises 426 consecutive patients operated for intractable mTLE. Impact of preoperative seizure onset and IED on the persistence of seizures and results of reoperation were analyzed. One year after surgery, 27% of patients with mTLE experienced persistent seizures (Engel II–IV). Preoperative bilateral seizure onset in EEG was predictive for postoperative seizure recurrence (Engel II–IV: 64%). Seizure foci and IED exceeding the temporal lobe in the ipsilateral hemisphere were not found to be associated with worse seizure outcome (Engel I: 72% and 75%) compared to patients with seizure foci confined to the ipsilateral temporal lobe (Engel I: 75% and 76%). Moreover, IED exceeding the affected temporal lobe in the ipsilateral hemisphere or even bilateral IED did not negatively affect seizure freedom if seizure onset was strictly limited to the affected temporal lobe (Engel I: 85% and 65%, respectively). 60% of patients reoperated in the ipsilateral temporal lobe for persistent seizures became seizure free. Preoperative bilateral ictal foci are a negative predictor for seizure outcome. Contrarily, IED exceeding the affected temporal lobe in the ipsilateral hemisphere or even bilateral IED had favorable seizure outcome if seizure onset is strictly limited to the affected temporal lobe. Reoperation for seizure persistence constitutes a promising therapeutic option.