LAUSR

OBJECTIVE Seizure outcome after extratemporal lobe epilepsy (exTLE) surgery has often been poorer than after temporal lobe epilepsy (TLE) surgery, but recent improvements in diagnostics and surgery may have changed this. Our aim was to analyze the changes in presurgical and surgical volumes and seizure outcome two years after surgery for patients with exTLE compared to those with TLE. METHODS We performed a retrospective, single-center cohort study including patients from the Bethel presurgical-surgical-postsurgical database from 1990 to 2017. We used logistic regression to analyze factors influencing the odds for surgery and the odds for seizure freedom after surgery. RESULTS We included 3822 patients with presurgical evaluation, 2404 of whom had subsequently undergone surgery. The proportion of exTLE patients in presurgical evaluation increased from 41% between 1990-1993 to 64% in 2014-2017. The odds for surgery decreased over time (2003-2011: OR=0.50 [95%CI 0.36-0.70]; 2012-2017: OR=0.24 [CI 0.17-0.35]; reference: 1990-2002), and patients with exTLE had lower odds for surgery than TLE patients, but this difference diminished over time (exTLE vs. TLE 1990-2002: OR=0.14 [CI 0.09-0.20]; 2003-2011: OR=0.32 [CI 0.24-0.44]; 2012-2017: OR=0.46 [CI 0.34-0.63]). Etiology, the side of the epileptogenic lesion and invasive recordings additionally influenced the odds for surgery. The most frequent reasons for not undergoing surgery were the missing identification of a circumscribed epileptogenic zone or an unacceptable risk of postsurgical deficits in exTLE patients and the patient's decision in TLE patients. Compared to TLE patients, the odds for seizure freedom after surgery started lower for patients with exTLE in earlier years, but increased (≤2 lobes 1990-2002: OR=0.47 [CI 0.33-0.68]; 2003-2011: OR=0.62 [CI 0.44-0.87]; 2012-2017: OR=0.78 [CI 0.53-1.15]; ≥3 lobes 1990-2002: OR=0.37 [CI 0.22-0.62]; 2003-2011: OR=0.73 [CI 0.43-1.23]; 2012-2017: OR=1.46 [CI 0.91-2.42]). Etiology, age at surgery and invasive recordings were further predictors for the odds for seizure freedom. CONCLUSION Over the past 28 years, the success of resective surgery for patients with exTLE has improved. At the same time, the number of exTLE patients being evaluated for surgery increased as well as their odds for undergoing surgery.