Abstracts

Rationale: Temporal lobe surgery is of benefit for patients with medically refractory mesial temporal lobe epilepsy. The superior operative procedure for seizure control, a standard anterior temporal lobectomy (ATL) or a selective amygdalohippocampectomy (SAH), has yet to be established. The objective of this study was to compare seizure outcome between ATL and SAH. Methods: We searched Medline and Embase using Medical Subject Headings and keywords related to ATL and SAH. Two reviewers independently screened abstracts and full-texts and abstracted data from eligible studies. We resolved any disagreement through consensus discussion. We included original research that directly compared quantified seizure outcomes in patients undergoing SAH or ATL for temporal lobe epilepsy. We did not restrict studies on the basis of sample size but did exclude those with less than 15 participants in any arm in a pre-specified sensitivity analysis. We investigated heterogeneity using the I2 statistic and the Cochrane Q statistic. Publication bias was assessed through evaluation of funnel plots. In the absence of heterogeneity, a fixed effect model was used to derive a pooled odds ratio (OR) for either an Engel class I (free of disabling seizures) or a composite of an Engel class I and II (rare disabling seizures) outcome. Results: Of 4675 abstracts initially identified by the search 65 were reviewed in full-text. Fifteen studies met all eligibility criteria. We excluded two studies from the meta-analysis that reported data from the same population of patients that were included in more recent studies. The remaining 13 studies contained data from 8 countries (5 continents) and included patients of all age ranges. Eleven studies comprising 1203 patients demonstrated that participants were statistically more likely to achieve an Engel class I outcome following ATL compared to SAH (OR 1.56, 95% confidence interval [95%CI] 1.18 to 2.05, p = 0.002). The result remained significant in a sensitivity analysis in which two studies that contained <15 participants in at least one arm were excluded (OR 1.57, 95%CI 1.18 to 2.09, p = 0.002). Eight studies comprising 983 patients demonstrated that participants had a statistically similar chance of achieving an Engel class I or II outcome following ATL or SAH (OR 1.12, 95%CI 0.78 to 1.61, p = 0.53). Studies were robust to potential publication and reporting bias. Conclusions: Standard ATL confers an improved chance of achieving freedom from disabling seizures in patients with temporal lobe epilepsy according to this pooled analysis of available studies. Improved seizure freedom must be balanced against the neuropsychological impact of each procedure. A randomised controlled trial is justified.