Surgery for extratemporal nonlesional epilepsy in adults: an outcome meta-analysis

To better evaluate surgery for extratemporal lobe epilepsy (ETLE) in adults, we conducted a meta-analysis of previous studies that analyzed postoperative seizure outcomes for ETLE. After searching PubMed for appropriate studies, patient data were reviewed, and data on patients who fit the authors' criteria were extracted. Statistical analysis compared each variable with surgical outcome to determine if an association existed. For the 131 patients who were included in the analysis, the age at surgery, age of seizure onset, and duration of epilepsy were not found to be statistically and significantly related to seizure outcome. Similarly, seizure semiology, abnormality on magnetic resonance imaging, lateralization of the seizures, the need for intracranial monitoring, pathological findings, and the type and location of surgery did not appear to be associated with outcome. This meta-analysis confirms the findings of other centers: ETLE surgical outcomes are less desirable than those for temporal lobe epilepsy. None of the factors studied in adults showed significant association with outcome. Contrary to some reports, shortening the duration of epilepsy by pursuing surgery as early as possible also does not appear to improve outcomes. The creation of standard protocols among epilepsy centers is needed to allow for a detailed evaluation of outcomes across different centers and, ultimately, to better assess the factors associated with improved outcomes.