Significance of sharp waves in routine EEGs after epilepsy surgery.
We retrospectively analyzed the presence of sharp waves in 2-h EEGs performed 6 months after epilepsy surgery in 59 patients. To study the significance of the postoperative interictal epileptiform activity in the tissue remaining after resection, we included only patients with a single epileptic focus (as defined preoperatively by prolonged video/EEG recordings and subdural electrode arrays studies) and no progressive structural lesions. Temporal lobectomy was performed in 51 patients (86%); extratemporal resections were performed in the remainder. The epileptogenic focus was completely resected in 26 patients (44%). The immediate postoperative electrocorticograms (EcoG) showed spikes in 13 patients (22%). At 6-month follow-up, 43 patients (73%) were seizure-free or had auras only and 12 patients (20%) had epileptiform activity on EEG. A significant correlation was noted between presence of sharp waves in the 6-month postoperative EEG and recurrence of seizures (Fisher's exact test p = 0.011) and also with the extent of the resection (complete vs. incomplete p = 0.042). We noted no correlation between postoperative epileptiform activity and location of the resection (temporal vs. extratemporal), presence of spikes in immediate postoperative EcoG, or occurrence of auras only at 6-month follow-up.
Godoy
J
J
Section of Epilepsy and Clinical Neurophysiology, Cleveland Clinical Foundation, Ohio.
Lüders
H
H
Dinner
D S
DS
Morris
H H
HH
Wyllie
E
E
Murphy
D
D
D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000503:physiopathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods; D004828:Epilepsies, Partial / Q000503:physiopathology / Q000601:surgery; D004827:Epilepsy / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011379:Prognosis; D012008:Recurrence; D012189:Retrospective Studies; D013702:Temporal Lobe / Q000503:physiopathology / Q000601:surgery