Predictive value of electrocorticography for postoperative epilepsy in patients with supratentorial meningioma.

This study examines electrocorticography (ECoG) signals in patients with supratentorial meningioma before and after tumor resection, and discusses its predictive value with regard to postoperative epilepsy. Ninety-one patients with supratentorial meningioma, who presented with seizures, were studied. Patients were followed-up for 2 to 5 years, and the occurrence rate of postoperative epilepsy in each group was compared. Depending on the frequency and amplitude variation in multiple spike waves on ECoG, patients were divided into those with an increase in epileptic discharge (Group A), those with no change (Group B), and those with a reduction in epileptic discharge (Group C). Postoperative seizures was classified as early postoperative seizures (within 1 week of surgery) or late postoperative seizures (> 1 week after surgery). After lesion resection and measurement of ECoG, the 91 patients were divided into Group A (12 patients, 13.19%), Group B (36 patients, 39.56%) and Group C (43 patients, 47.25%). Of these 91 patients, 29 (31.87%) had early postoperative seizures of which seven patients (58.33%) were from Group A, 13 (36.11%) were from Group B and nine (20.93%) were from Group C (χ(2)=6.53, p<0.05). Seventeen patients (18.68%) had late postoperative seizures, of which two patients (16.67%) were from Group A, seven were from Group B (19.44%) and eight were from Group C (18.60%) (χ(2)=0.05, p>0.05). Of the 29 patients with early postoperative seizures, seven (24.14%) also had late postoperative epilepsy. Of the 62 patients who did not experience early postoperative seizures, 10 (16.13%) also had late postoperative epilepsy (χ(2)=0.83, p>0.05). Thus, the change in ECoG before and after resection in patients with supratentorial meningioma has a predictive value for early postoperative seizures.