Abstracts

Rationale: Epilepsy surgery has become a common treatment for pharmacoresistant epilepsy. Previous research has shown that outcome may vary after surgery depending on type of neuropathology, as well as prognostic factors. Recent studies have shown that 60%-70% of patients have favorable outcome after temporal lobe resections (McIntosh et al., 2001), especially when accompanied by hippocampal sclerosis (Radhakrishnan et al., 1998, Janszky et al, 2005). Therefore, effectiveness of surgical treatment should be evaluated consistently in order to document its efficacy. Methods: 281 patients underwent standard anterior temporal lobectomy for intractable epilepsy at the University of Florida Adult Comprehensive Epilepsy Center between August 1992 and December 2003. 249 patients (RATL = 126; LATL = 123) met the following inclusion criteria: a) were 16 years or older, b) underwent Phase 1 epilepsy monitoring, and c) were treated by the same neurosurgeon. Patients with multiple pathologies were excluded. 84.3% of patients were retained at 12 months post-operatively. Satisfactory seizure freedom was categorized as if there was no recurrence of seizures or limited to auras or breakthrough seizures due to non-compliance with medication (Engel Score of Ia or b).Results: Overall, 70% of patients were seizure free 12 months post-operatively. 72% of patients who underwent LATL were seizure free at one year compared to 69% of those who underwent RATL. When examining pathology independent from side of surgery, patients with MTS (74%) had a greater chance of being seizure free than patients without MTS (60%). When split by side of surgery, RATL patients with MTS (76%) were more likely to have achieved seizure remission at 12 months, as opposed to RATL patients without MTS (53%). Similarly for LATLs, when patients had MTS they had a greater chance of being seizure free at 12 months (72%) than patients without MTS (67%). Overall, there were no statistically significant differences between satisfactory outcome when considering side of surgery or pathology. Outcome at 24 months post-operatively will also be discussed. Conclusions: Surgical treatment for intractable temporal lobe epilepsy is effective. Side of surgery had no influence over seizure outcome independently. When MTS was observed in patients, there was a trend for improved seizure freedom at 12 months compared to patients without evidence of MTS but this was not statistically different. Other factors that may affect seizure freedom such as: age at surgery, epilepsy duration, and seizure frequency will also be discussed.