Acute postoperative seizures as predictors of seizure outcomes after epilepsy surgery.

OBJECTIVES: This meta-analysis was performed to determine if acute postoperative seizures (APOS) predict epilepsy surgery outcomes. Additionally, we estimated pooled prevalence for APOS and explored if certain APOS characteristics predict surgical outcomes.

METHODS: A systematic literature search was performed for studies reporting seizure outcomes after epilepsy surgery in patients with and without APOS. APOS were defined as seizure(s) occurring within 30days of surgery. After data extraction, pooled Mantel-Haenszel odds ratio (OR) with 95% confidence intervals (CI) was calculated for 1-year seizure-free outcome in patients with and without APOS using random-effects meta-analysis. Sub-group meta-analysis for pediatric studies, time of occurrence, and APOS semiology were also performed. A meta-regression was performed to explore source(s) of heterogeneity.

RESULTS: Seventeen studies were included in the final synthesis. Pooled prevalence of APOS was found to be 22.58%. A significantly higher proportion of patients without APOS within 30days of surgery (73.49%) were seizure-free at ≥1-year (OR 4.20, 95% CI 2.97-5.93, p<0.0001) compared to those with APOS (38.96%). Among the pediatric studies (n=6) 77.14% of patients without APOS were seizure-free at ≥1-year, compared to 35.94% of those with APOS (OR 5.71, 95% CI 3.32-9.80, p<0.0001). Patients having APOS within 24h of surgery and APOS semiology different from habitual pre-surgical seizures were more likely to achieve seizure-free outcomes, but these results failed to achieve statistical significance.

CONCLUSIONS: APOS reliably predict 1-year seizure outcomes after epilepsy surgery. This information should help counsel patients and families.