Objective         To investigate the relationship of residual epileptiform discharges including spikes

ripples and fast ripples (FR) in post-resection intraoperative electrocorticography (ECoG) in the patients with refractory focal epilepsy with seizure recurrence after epilepsy surgery.  Methods        We studied

retrospectively

ECoG recorded after resection in a total of 71 patients with refractory focal epilepsy treated in our neurosurgery department from January 2010 to January 2015. Follow-up period was within 1 to 5 years after surgery. Patients were subdivided into positive(+) and negative(-) groups depending on whether they had onset of residual events. We analyzed occurrence and number of residual spikes (1~40 Hz

spike group)

ripples (80~250 Hz

R group) and FR (250~500 Hz

FR group) within the last minute of each recording and compared these to seizure recurrence.   Results      The mean postoperative follow-up period was 2.3±1.5 years. Among 71 patients

26 patients had recurrent seizures (Engel-Ⅰb~Ⅳ) and 45 patients were seizure free (Engel-Ⅰa). The seizure recurrence was significantly higher in FR(+) vs FR(-) patients (12/17 vs 14/54

P0.01)

and its positive predictive value (PPV) was 70.59%. Also

the patients with recurrent seizures had higher FR rates than seizure-free patients (7.62±1.19 vs 5.24±1.30，P0.01). In spike and R groups

there was no significant difference in the type and number of residual events between seizurerecurrent and seizur-free patients (P0.05).  Conclusion       Residual FR in post-resection intraoperative ECoG may be an electrophysiological marker for seizure recurrence in the patients with refractory focal epilepsy. Moreover

the higher residual FR is closely associated with seizure recurrence after surgery.