Abstract
Objective
We conducted a systematic review and meta-analysis to evaluate postoperative seizure and memory outcomes of temporal lobe epilepsy with different hippocampal sclerosis (HS) subtypes classified by ILAE Consensus Guidelines in 2013.
Method
Following the PRISMA and MOOSE guidelines, we searched PubMed, Embase, Web of Science, and Cochrane Library from January 1, 2013 to August 6, 2023. Observational studies reporting seizure and memory outcomes among different HS subtypes were included. We used the Newcastle-Ottawa scale to assess the risk of bias and the GRADE approach to grade the quality of evidence. Seizure freedom and improved outcome (Engel 1 or ILAE class 1-2) ≥1 year after surgery were defined as the primary and secondary seizure outcome. A random-effects meta-analysis with DerSimonian and Laird method was performed to obtain pooled risk ratio (RR) with 95% confidence interval (CI). The memory impairment was narratively reviewed because of various evaluation tools.
Results
Fifteen cohort studies with 2,485 patients were eligible for the meta-analysis of seizure outcome. Six cohorts with detailed information of postoperative memory outcome were included. The pooled RR of seizure freedom, with moderate to substantial heterogeneity, were 0.98 (95% CI 0.84 to 1.15) between HS Type 2 and Type 1, 1.11 (95% CI 0.82 to 1.52) between Type 3 and Type 1, and 0.80 (95% CI 0.62 to 1.03) between no-HS and HS group. No significant difference of improved outcome was found between different subtypes (P >0.05). The quality of evidence was deemed as low to very low according to GRADE. The long-term seizure outcome (≥5 years after surgery) and memory impairment remained controversial.
Significance
Similar postoperative seizure outcome and inconsistent postsurgical memory changes were found among different HS pathological subtypes. Multiple factors including but not limited to pathological changes, may influence the postsurgical seizure and cognitive outcomes.
AGO