Abstracts

Rationale: Many reports demonstrate the possibility of favorable outcome following temporal lobe epilepsy surgery. Data varies by center, but seizure freedom or significant reduction in seizure frequency is reported previously. We aim to review the outcome data in our institution for temporal lobe epilepsy surgery in younger age (less than 20 years of age) in order to determine indicators for favorable outcome. Methods: We retrospectively reviewed the epilepsy surgery data base who underwent temporal lobe resection due to intractable epilepsy between 1992 and 2009 at the Medical College of Georgia. We examined demographic data, clinical history, EEG, MRI, neuropathology, and follow up at 1, 3 and 5 years with Engle classification. We focused the analysis on resection types and tissue diagnosis by postsurgical neuropathological examination. Surgical types were categorized as anterior temporal lobectomy (TL), lesionectomy (Le), amygdalohippocampectomy (AH), and temporal lobectomy with sparing of the hippocampus (TLwo). Pathology was categorized as mesial temporal sclerosis (MTS), cortical dysplasia (CD), gliosis (G), tumor (T) and dual pathology (D). Statistical analysis was done by ANCOVA. Results: Ninety cases (mean age, 12.9 years; range 0.5 and 20 years of age) were included; 51 males, 39 females. Of the 90 cases (Lt 52, Rt 38), there were 64 TL, 14 TLwo, 8 Le, and 4 AH. Combining all surgical types, good outcome (Engel I or II) was achieved in 94.4% (85/90) at one year, 87.8% (72/82) at year three, and 81.7% (49/60) at year five follow up. Separate analysis of the surgical types reveals better outcome in the TL group with good outcome in 98% (63/64) at one year, 91.5% (54/59) at 3 year, and 83.3% (40/48) at five year. In contrast, poorer outcome was observed in the TLwo group (Lt 11, Rt 3) with good outcome being achieved in 78.6% (11/14) at one year, falling to 69% (9/13) at three year, and to 67% (4/6) at five year follow up (p=0.09). Thirty one (34%, Lt 22, Rt 9) of the patients required invasive monitoring with depth electrode and grid placement prior to resective surgery. Reviewing pathology, 28 patients had MTS, 16 with cortical dysplasia, 9 with tumors, 14 with gliosis, and 23 with dual pathology. Those with MTS had the best outcome with persistent benefit, 100% (28/28) good outcome at 1 year, 96% (26/27) at 3 year, and 95% (20/21) at 5 year. The presence of gliosis indicated a propensity to lose seizure control over time, with 1 year good outcome in 92% (13/14). However, at 3, 5 years, the benefit dropped to 70% (7/10) and 62.5% (5/8) respectively. A similar trend was noted in dual pathology as well as cortical dysplasia (p=0.14). Conclusions: We conclude that TL with the presence of MTS has the favorable outcome with sustained benefit. The poor outcome was observed in patients with TLwo. The presence of MTS has tendency of the better outcome while gliosis offers a poorer predictive outcome.