Abstracts

Rationale: Despite new anti-epileptic therapy options, more than 30% of patients with epilepsy will become medically intractable. There have been many studies demonstrating the efficacy of temporal lobe surgery in short term follow up, but fewer studies with long term seizure freedom data. The goal of this study was to determine the long term outcomes of epilepsy surgery at a comprehensive epilepsy center. Methods: Upon obtaining IRB approval, we performed a retrospective review of 162 patients that had temporal lobe surgery (92 left and 70 right temporal lobectomies) at Rush University Medical Center between 1/18/96 and 2/5/09. Patients were aged 18 years or older at time of surgery. Patients’ surgical outcome using the Engel classification was documented at 5, 10, 15, and 20 years in addition to the most recent follow up appointment. Results: 162 patients (91 female, 71 male) met inclusion criteria. 20 patients were lost to follow up and excluded from the analysis. Patients were followed for an average of 13.3 years (± 5.2 years). 110 patients were Engel class I, 78 of which were class 1A at their last follow up. 82.5% of patients followed for 15 years were class I and 78.6% of patients were class I at 20 years of follow up. Neither age of onset nor duration of epilepsy at surgery were associated with a particular outcome, likewise pre-operative seizure frequency did not predict seizure outcome post-operatively. At last follow up appointment, 86% of those who underwent a left temporal lobectomy versus 66% after a right temporal lobectomy, achieved seizure freedom, p = 0.002. The extent to which the hippocampus was resected was associated with better outcomes, surprisingly those with a partial resection had better seizure freedom, p < 0.0001. Conclusions: This large cohort of patients with TLE demonstrates that the majority of patients achieve long term seizure freedom after temporal lobe resection. Further analysis is currently underway to determine predictive factors of outcome, as initial analysis yielded unexpected results. Left temporal lobectomy outcomes were better and could be due to a more thorough and certain work up given the dominant temporal lobe being resected. Seizure freedom remained relatively consistent over a long period of follow up, suggesting that early seizure freedom post-operatively will be maintained long-term. Funding: No funding