Abstracts

Rationale: Epilepsy is a common pediatric neurologic disorder, affecting 0.5-1% of all children. The majority of children, 70-80%, are able to achieve good seizure control with medications. For those with medically intractable epilepsy and a surgically remediable focus, seizure freedom may be attained through epilepsy surgery. In children, neocortical resection results in seizure freedom in 60-91% of temporal lobe resections and 54-66% of extratemporal resections. Although the primary goal of epilepsy surgery is seizure freedom or seizure reduction, a secondary goal of many of the patients and families is anti-epileptic medication (AED) reduction or discontinuation. There are few studies reported on AED withdrawal in children following epilepsy surgery. They suggest that overall risk of seizure recurrence is not higher in those that withdraw medications. However, Neurologists remain hesitant to withdraw medications due to concern of causing seizure recurrence. Therefore, the aim of this study is to determine whether seizure recurrence occurs more often in children in whom AEDs are withdrawn following successful epilepsy surgery. Methods: The medical charts of all children, age birth through 17 years undergoing epilepsy surgery at Mayo Clinic Rochester from January 2008 through December 2012 were reviewed to determine: 1) Number of medications and non-medication therapies (ketogenic diet or VNS) tried before surgery 2) Number of medications and non-medication therapies being used at the time of surgery 3) When, if at all, therapies were withdrawn after surgery 4) Number of medications and non-medications being used at last follow-up 5) Seizure outcome, based on Engel classification at 3 months, 6 months, 12 months, 24 months, 36 months, and final outcome after surgery. Results: From January 2008 through December 2012, 79 children underwent resective surgery for intractable epilepsy. Of those, 50 were seizure free at 3 months and 49 were treated with AED. Average duration of follow-up was 33.6 months. Overall, 28 reduced AEDs and 37 were seizure free at last follow-up. At each time point, those who did withdraw AEDs were not significantly more likely to have seizure recurrence than those who did not. At last follow-up, those who withdrew AEDs were more likely to be seizure free than those who did not (86% vs 62%, p=0.001). Children for whom epilepsy surgery was expected to be curative, rather than palliative surgery, were significantly more likely to be seizure free at last follow-up, with or without AED withdrawal (89% vs 42%, p<0.001).Conclusions: In this study of children who underwent resection for intractable epilepsy and who were seizure free 3 months postoperatively, 74% were seizure free at last follow-up. AED withdrawal was not a significant risk factor for seizure recurrence, regardless of when AED withdrawal occurred. Therefore, children who are seizure free following resective surgery for epilepsy should be considered for AED reduction.