Long-term seizure outcomes in patients with drug-resistant mesial temporal lobe epilepsy due to hippocampal sclerosis.
OBJECTIVE Resective surgery is a significant therapeutic option for patients with drug-resistant mesial temporal lobe epilepsy (MTLE) due to hippocampal sclerosis (HS). Numerous studies have demonstrated the efficacy of epilepsy surgery in the short to median term. However, studies on long-term outcomes are limited in number. The objective of this study was to document the long-term prognosis and associated factors of patients undergoing resective surgery for MTLE. METHODS A retrospective analysis was conducted on the data of patients with drug-resistant MTLE due to HS who underwent resective surgery between 2001 and 2013 at our epilepsy centre. The demographics and clinical variables of the patients were documented and analysed in order to ascertain their long-term prognosis. The postoperative outcomes were evaluated in accordance with the Engel classification system. RESULTS Of the 45 patients (mean age: 44.64 ± 8.96, range: 31-67), 31 (68.89%) were male. The age at onset of epilepsy, age at surgery, and the duration of epilepsy at the time of surgery ranged from 0.25 to 26 years (11.51 ± 7.07), from 12 to 47 years (26.82 ± 8.14), and from 2 to 33 years (16.03 ± 7.85), respectively. The patients were followed up for 10-23 years (17.73 ± 2.96). HS was identified in 23 (51.11%) of the patients on the right side and 22 (48.89%) on the left. The pre-operative EEG recordings revealed temporal discharges in 40 (88.89%) patients unilaterally. 22 patients (48.89%) underwent amygdalohippocampectomy with a temporal lobectomy (AH+ATL), while 23 patients (51.11%) underwent selective amygdalohippocampectomy (SAH). 28 (62.22%) patients were classified as Engel I. The patients did not have any statistically significant difference in terms of gender, age at epilepsy onset, age at surgery, duration of epilepsy at surgery, side of HS, and surgical procedure according to Engel classification (p = 0.64, 0.08, 0.60, 0.25, 0.67, 0.10, respectively). Executive and memory functions were improved after surgery at 5th year. CONCLUSION 62% of the patients were classified as Engel I. Although previous studies have suggested that certain factors may influence prognosis, our findings did not yield any statistically significant results in this regard. It is crucial that patients undergo surgical evaluation without delay to achieve seizure control and improve cognitive function.