Surgical outcomes for extratemporal lobe epilepsy: A systematic review and meta-analysis

Surgical outcomes of extratemporal lobe epilepsy (ETLE) have traditionally been less favorable than outcomes after surgery for temporal lobe epilepsy (TLE), likely related to challenges with defining the seizure onset zone and epileptogenic network, as well as involvement of eloquent cortex limiting options for surgical resection. This systematic review and meta-analysis aims to identify factors associated with seizure freedom among patients with ETLE.

We performed a systematic review and one-stage individual patient data (IPD) meta-analysis to identify outcome predictors among patients with ETLE. The primary endpoint of seizure-free survival was defined as patients who are at most Engel 1 at last follow-up. Potential predictors of the primary endpoint included sex, seizure type, MRI lesion, pathology, age at onset, age at surgery, location of surgery and lateralization.

Raw data from 363 patients from 26 studies were included. Median age of seizure onset was 11 years, while median age at the time of surgery was 28 years. Multilobar resections (HR 1.56 (95% CI 1.01-2.45, p = 0.05)) and left-sided surgery (HR 1.46 (95% CI 1.02-2.10, p = 0.03)) were the only variables associated with significantly worse seizure-free survival in a reduced pooled Cox analysis. Seizure-free survival was 66% following ETLE surgery.

Multilobar resections and left-sided surgery were independently associated with less favorable seizure outcomes amongst patients with ETLE, underscoring the need for refined presurgical localization strategies and tailored surgical approaches in ETLE. Seizure freedom was higher than prior ETLE reviews suggesting that modern epilepsy approaches have improved outcomes over time.