Abstracts

Rationale: Outcome following surgery for extratemporal epilepsy is known to be less favorable than for temporal lobe resections in both adult and children. Frontal lobe surgery is further complicated by presence of language and motor cortex whic often limit the extent of resection. Epilepsy surgical outcomes were reviewed for a series of children with frontal lobe surgery, with specific attention to the influence of age and etiology on long term seizure control.Methods: Retrospective review of epilepsy surgery cases in 2 institutions was performed. 35 children with frontal lobe surgery were identified. 3 children underwent a second frontal lobe resection following an unsuccessful first surgery for a total of 38 surgical procedures. Data collected included etiology, age at surgery, surgery type, use of invasive monitoring with subdural electrodes and seizure frequency. Seizure outcome was classified by modified Engel criteria. Mean duration of follow up was 2.5 years, (range 6 months to 6 years). Results: 30 children underwent resection alone, 6 had resection plus multiple subpial transections (MSPT), and 2 had MSPT only. Invasive monitoring with subdural electrodes was used in 26 cases. Mean age at surgery= 10.3 years(range 3 mos - 18 years). Mean preoperative seizure frequency = 3.5/day(Range 24/day - 1/month). Etiology was cortical dysplasia (CD)=10 cases, tumor in 5, infarct/atrophy=7, cavernoma=3 and none=13 17 children were free of disabling seizures following surgery (Engel Class 1), 3 had only rare disabling seizures (Class 2), 10 had at least 50% seizure reduction (Class 3) and 8 had no worthwhile improvement (Class 4). Overall older children did better than younger. 16/28 children age 6+18 years had Class 1 or 2 outcomes and only 4 had class 4 outcomes. 4/9 children undear age 6 had class 1 outcomes, 1 had a class 3 outcome and 4 had class 4 outcomes. Etiology did not seem to be a significant factor in outcomes for children under age 6, among the 9 children inthis sample 7 had CD, 3 with class 1 outcome, one class 3 and 3 class 4 outcome. Of the 3 young chidren with class 4 outcome and CD, 2 became seizure free following hemispherotomy. All older patients with CD (n=3)and tumor (n=4)acheived Class 1 outcome (one tumor patient initially had seizures but became seizure free after a second resection). Only 4/7 patients with infarct/atrophy and 4/11 patient with no visible lesion on preoperative imaging had a favorable Class 1 or 2 outcome. 2 patients with no lesion had a seoond frontal lobe resection, neither acheived a Class 1 or 2 outcome. Conclusions: Frontal lobe epilepsy surgery had a favorable outcome in more than half of children. 45 % had a class 1 outcome and only 21% had no worthwhile benefit. Most children with cortical dysplasia benefitted from surgery but among younger children 2 of 7 ultimately required hemispherotomy. Consistent with other case series, patients without a visible lesion had worse results with 38% Class 1 or 2 outcome.