Abstracts

Rationale: Temporal lobe epilepsy is the most common type of epilepsy requiring surgical treatment with a majority of these patients having mesial temporal sclerosis (MTS). Surgical outcome has been reported to be favorable ranging from 70-80% seizure freedom after resection. Previous reports evaluating predictors of surgical outcome in patients with MTS have shown that dual pathology, normal MRI, duration of epilepsy and history of secondary generalized seizures affect outcome. There have been extensive studies evaluating MTS in adults with limited studies in children and adolescents being included within both patient populations. Our aim was to evaluate predictors of surgical outcome solely in adolescent patients with MRI and pathology proven MTS. Methods: The Yale Epilepsy Surgery Database was reviewed from 1987-2003 for adolescent patients(age 12-18 at time of surgery) with confirmed MTS on MRI and pathology who underwent temporal lobectomy and had greater than two year post surgical follow-up. Clinical information regarding duration of epilepsy, current and history of AED use, risk factors including febrile seizures, secondary generalized seizures, and auras was gathered. Electrographic data evaluated was interictal and ictal findings on scalp EEG as well as intracranial EEG if performed. Statistical Analysis was performed using the Fisher's exact test. Results: A total of 22 patients were identified, 17 of whom had greater than two year post surgical follow-up data available. Median age at surgery was 16 with post-surgical follow-up ranging from 2-18 years. Duration of epilepsy ranged from 2-17 years with a median of 10 years. Eleven patients had left MTS, six right MTS and one bilateral MTS. Surgical outcome was classified as good (Engel Class I-II) and bad (Engel Class III-IV). Fourteen patients (82%) had good surgical outcome (11 Engel Class 1 and 3 Engel Class 2), with only one patient off AEDs completely. All three patients (18%) with poor surgical outcome were found to have diffuse ictal onset on EEG involving more than one lobe. There were no significant predictors of outcome within this cohort. Conclusions: The majority of adolescent patient with MTS who underwent temporal lobectomy had good surgical outcome as seen previously in other studies. However our study did not find that epilepsy duration, history febrile seizures, generalized seizures or auras had any influence on surgical outcome in this cohort of adolescents with MTS. Ictal onset arising from more than one lobe on EEG was a predictor for poor outcome (p=0.05).