Postoperative interictal epileptiform discharge within 1 month is associated with seizure recurrence after anterior temporal lobectomy

To investigate the relationship of interictal epileptiform discharges (IEDs) within 1 month of anterior temporal lobectomy (ATL) to seizure outcome, we reviewed data for 202 (107 left ATL, 95 right ATL) patients who had undergone ATL for mesial temporal epilepsy. Postoperative EEGs within 30 days and other preoperative variables were analyzed to examine the significant factors that determine freedom from disabling seizures. IEDs were noted in 29 (22.3%) of the 130 patients without seizures for 2 years after ATL compared with 31 (43.1%) of the 72 patients with recurrent seizures (P = 0.002). Postoperative IEDs remained an independent predictive factor for seizure outcome by logistic regression (adjusted OR = 2.38, 95% CI = 1.18–4.81, P = 0.016, 2 years postoperatively; adjusted OR = 2.22, 95% CI = 1.03–4.82, P = 0.043, 5 years postoperatively) and Cox hazard regression analysis (adjusted HR = 1.76, 95% CI = 1.18–2.62, P = 0.006) after controlling for other predicting factors (unilateral hippocampal atrophy, history of febrile seizures, and IQ scores). In this study, IEDs on the EEG obtained soon after surgery were associated with postoperative seizure recurrence. These results can be used in the assessment of risk of seizure recurrence after ATL.

Research Highlights
► Postoperative IEDs were associated with seizure recurrence after ATL.
► Multivariate logistic analysis showed an OR of 2.38 for seizure recurrence within 2 years after ATL.
► The probability of seizure recurrence was related to the location of postoperative IEDs.