Abstracts

RATIONALE: Surgery is now well established in the management of selected pediatric patients with medically resistant epilepsy. However, there is limited information about very long-term seizure outcome following surgical treatment. We present our experience regarding seizure status in children 10 years after excisional procedures and corpus callosotomy.
METHODS: Children were identified from the Miami Children[ssquote]s Hospital Epilepsy Surgery database and surgical charts were reviewed. We recorded the following parameters: seizure type, neuroimaging, seizure status at two, five and ten years and pathologic diagnosis. Follow up data was obtained through clinic visits or by telephone interview. Seizure outcome was classified according to Engel[ssquote]s criteria.
RESULTS: From a cohort of 93 children operated on between 1980 and 1992, we identified 59 children who were alive and had data at 10 years after surgery. Age at surgery ranged from five months to 18 years (mean = 8.7 years). Fifty-three (90%) had partial seizures and underwent excisional procedures [23 (39%) temporal, 23 (39%) extratemporal, 7(19%) hemispherectomy] and 6 (10%) had generalized seizures and underwent corpus callosotomy (complete, 3; anterior 2/3, 3). Pathological information was available in 51 cases: cortical malformation, 25 (49%), encephalomalacia, 7 (14%), tumor, 12 (24%), hippocampal sclerosis, 2 (3%), infection, 4 (8%) non-specific, 1 (2%). At 2 year follow up 27 (46%) were seizure free, 21 (36%) showed worthwhile improvement and 11 (18%) were marginally improved or unchanged. At 5 year follow up 18 (31%) were seizure free, 23 (39%) showed worthwhile improvement and 18 (30%) were marginally improved or unchanged. At 10 year follow up 20 children, 8 temporal and 12 extratemporal, (34%) were seizure free, 23 (39%) showed worthwhile improvement while 16 (27%) were unchanged. Seizure freedom was higher among lesional (65%) when compared to non-lesional (35%) cases. Five of six children who underwent callosotomy were unchanged at 10-year follow up. Forty-five children (76%) remained on anticonvulsant treatment. Relapse rates were highest in the first two years after surgery.
CONCLUSIONS: Approximately one third of children who undergo excisional procedures are seizure free at 10 years. Children with a lesion on neuroimaging were more likely to remain seizure free. A favorable outcome was independent of underlying pathology. In contrast, no child who underwent callosotomy was seizure free. Relapse rates were highest within the first two years after surgery, declined until 5 years postoperative and plateaued thereafter. Seizure freedom at 5 years after surgery is a good predictor of permanent seizure remission.