Is inpatient ictal video‐electroencephalographic monitoring mandatory in mesial temporal lobe epilepsy with unilateral hippocampal sclerosis? A prospective study

Summary Objective To compare surgical outcome in mesial temporal lobe epilepsy ( MTLE ) patients with unilateral hippocampal sclerosis ( MTLE ‐ HS ) who had or did not have preoperative video‐electroencephalographic monitoring ( VEEG ). Methods A prospective study was undertaken with 166 consecutive pharmacoresistant unilateral MTLE ‐ HS patients. All patients were investigated with detailed seizure semiology, serial routine outpatient EEG , magnetic resonance imaging, neuropsychological evaluation, and if necessary, other examinations. Postoperative follow‐up ranged between 2 and 16 years. Patients were divided into: (1) patients operated on based on routine outpatient EEG information, with >80% of EEG s with unilateral interictal epileptiform discharges ( IEDs ) ipsilateral to HS or ictal events (n = 71); and (2) patients submitted to preoperative VEEG (n = 95). To avoid the bias generated by ictal recordings, we performed a subanalysis of: (1) patients without preoperatively ictal recordings (n = 80) and (2) patients with ictal recordings in VEEG or routine outpatient EEG (n = 86). Results Groups were similar regarding gender, age at surgery, seizure onset, preoperative seizure frequency, and duration of follow‐up. Overall, 136/166 (81.92%) were classified as Engel I seizure outcome, with no difference between groups; 76.84% and 88.73% of patients with and without VEEG , respectively, had Engel I postoperative seizure outcome ( P  = .77). The time lag until surgery was shorter in the group without VEEG (80 vs 38 months; P  = .01). Considering ictal recordings, 76.74% of patients with seizures recorded and 87.50% without ictal recordings had Engel I outcome ( P  = .11). Significance We performed the first prospective study in a tertiary epilepsy center comparing surgical outcomes in unilateral MTLE ‐ HS patients investigated preoperatively with and without VEEG . Based on the surgical outcome, VEEG is not imperative in patients with unilateral MTLE ‐ HS who have compatible semiology and clearly ipsilateralized IED s evaluated by a multidisciplinary and experienced epilepsy group.