Abstracts

Rationale: The reason of surgical failure for mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS) remain unclear. We intended to investigate what factors affect the prognostic effect on the post-surgical outcome in patients with MTLE with HS in this study.  Methods: We retrospectively reviewed the data from 380 surgeries (anterior temporal lobectomy) performed between 1995 and 2016 on patients at Samsung Medical Center. We studied the prognostic value of demographic data and a variety of preoperative evaluations which can suggest an excellent surgical outcome during the follow-up at least more than a year.  Results: Among 380 subjects, seizure free (SF) was observed in 246 patients (64.7%). In SF group, their ictal onset EEG patten was unilateral (78.9%), bilateral (11.4%) and diffuse/extra-temporal onset (9.8%). Those from seizure free (NSF) patients (n=134) was 82.8%, 4.5%, and 12.7%, respectively. No significant correlation was found between ictal EEG laterality and postoperative seizure control between two groups (p>0.05). Among 323 patients with FDG-PET study, SF group (n=206) showed hypometabolism in a focal anteromesial temporal (34.0%), diffuse or extra-temporal areas (66.0%) and it was not different from those of NSF group (37.6% and 62.4%, respectively, p>0.05). Likewise, the hyperperfusion pattern of SISCOM study (n=219) showed no difference between two groups; localized within anteromesial area of resection side (13.2% of SF vs. 9.3% of NSF group) and diffuse temporal hyperperfusion (86.8% of SF vs. 90.7% of NSF group). Conclusions: Localized pattern of ictal onset EEG, FDG-PET and SISCOM findings toward the ictal focus, which are crucial for predicting postsurgical outcome of anterior temporal lobectomy was not applicable to the present investigation. It may imply that too many pre-surgical evaluations does not always render a good postsurgical outcome, especially in unilateral MTLE cases. Funding: None