LOW-GRADE GLIOMAS ASSOCIATED WITH INTRACTABLE EPILEPSY - SEIZURE OUTCOME UTILIZING ELECTROCORTICOGRAPHY DURING TUMOR RESECTION

Adults and children with low-grade gliomas often present with medicall y refractory epilepsy. Currently, controversy exists regarding the nee d for intraoperative electrocorticography (ECoG) to identify and, sepa rately, resect seizure foci versus tumor removal alone to yield maximu m seizure control in this patient population. Forty-five patients with low-grade gliomas and intractable epilepsy were retrospectively analy zed with respect to preoperative seizure frequency and duration, numbe r of antiepileptic drugs, intraoperative ECoG data (single versus mult iple foci), histology of resected seizure foci, and postoperative cont rol of seizures with or without antiepileptic drugs. Multiple versus s ingle seizure foci were more likely to be associated with a longer pre operative duration of epilepsy. Of the 45 patients studied, 24 were no longer taking antiepileptic drugs and were seizure-free (mean follow- up interval 54 months). Seventeen patients, who all had complete contr ol of their seizures, remained on antiepileptic drugs at lower doses ( mean follow-up interval 44 months); seven of these patients were seizu re-free postoperatively, yet the referring physician was reluctant to taper the antiepileptic drugs. Four patients continued to have seizure s while receiving antiepileptic drugs, although at a reduced frequency and severity. In this series 41% of the adults versus 85% of the chil dren were seizure-free while no longer receiving antiepileptic drugs, with mean postoperative follow-up periods of 50 and 56 months, respect ively. This difference was statistically significant (p = 0.016). Ther efore, based on this experience and in comparison with numerous retros pective studies involving similar patients, ECoG is advocated, especia lly in children and in any patient with a long-standing seizure disord er, to maximize seizure control while minimizing or abolishing the nee d for postoperative antiepileptic drugs.