Abstracts

Rationale: Temporal Lobe Epilepsy (TLE) is the type of partial epilepsy with the most favorable surgical outcome in adults. Surgical outcome is universally reported by using the Engel classification. Nevertheless, outcome reports from multiple epilepsy centers do not distinguish the subclasses (i.e. IA, IB, etc), not allowing for easy identification of patients completely seizure free after surgery. The proposed classification by the International League against Epilepsy (ILAE) aims at identifying such patients readily, and easily differentiating them from patients with post operative auras or with seizure recurrences compared with baseline seizure counts. Methods: Using a retrospective review, we compared these two classifications using a series of patients who underwent temporal lobe resections for temporal lobe epilepsy. Patient outcomes were classified using the Engel classification (including subclasses) and the proposed ILAE classification on a yearly basis on the anniversary of the surgery. Only patients in whom one year or more of data was available were included. Results: 29 patients were included (51% males) who underwent standard temporal lobectomies (51% left). The median age of epilepsy onset was 13 years old, median age at time of surgery was 37 years old and the median latency between epilepsy onset and epilepsy surgery was 18 years. Seizure outcomes were included for years 1 and 2 after surgery (Table 1) Conclusions: The Engel Classification of seizure outcome overestimates the number of patients who are truly seizure free after temporal lobectomy when the subcategories are not used consistently. The ILAE classification of seizure outcome allows for fast and easy identification of patients completely seizure free after epilepsy surgery. Longer follow up of these patients is needed to determine if this classification could predict true long-term (>5 years) seizure freedom