Abstracts

Rationale: Epilepsy surgery is an effective treatment option with seizure-free outcome in approximately 60-80% of cases. However, at least 20-40% of patients may continue to have seizures despite surgery due to a variety of reasons such as incomplete resection of the epileptogenic zone or secondary epileptogenesis. In a highly selected group of patients, re-operation could potentially improve seizure control. Few studies addressed the outcomes in children who underwent reoperation after a failed epilepsy surgery. The aim of this study was to assess the outcome of reoperations in children who have had prior respective epilepsy surgery. Methods: There were 309 children who have had respective epilepsy surgery between 2001 to 2013. Of these, 33 children (11%) underwent reoperation. Diagnostic evaluation including video EEG, MRI, magnetoencephalography was reviewed. Histology of the lesion was also obtained. Outcome measure was seizure control at 1 year after reoperation, which was assessed using the ILAE classification. Results: Of the 33 patients who underwent reoperations, 30 patients had two surgeries and three had three surgeries. 17 of the cohort were females. The mean age at first surgery was 6.2 years and at second surgery was 9.5 years. MEG was done for 27/33 cases and showed a cluster of dipoles in 22 cases (81%). MEG clustered dipoles was associated with seizure-free outcome in 72%, whereas scattered dipoles was associated with only 40% good outcome. Eight patients had redo hemispherectomy. 21 patients had extended cortical resections and 4 had hemispherectomy at second surgery. 1 patient had extended cortical resections, 1 had hemispherectomy and one had redo-hemispherectomy at third surgery. 69.7% of the patients underwent reoperations became seizure free at 1 year follow up. Conclusions: Reoperation may be a viable treatment option in selected patients who failed to achieve seizure control after initial surgery. Funding: non