Functional anterior temporal lobectomy for temporal lobe epilepsy: from anatomical resection to functional disconnection.

Objective: Although anterior temporal lobectomy (ATL) has the highest efficacy for temporal lobe epilepsy (TLE), there is currently a trend toward performing minimally invasive surgery (MIS) for TLE. However, the MIS methods, such as laser thermocoagulation, have been used at the expense of efficacy. Functional ATL (FATL), which involves functional disconnection instead of anatomical resection and was designed by the authors, resolves this problem. This study aimed to evaluate seizure outcomes of FATL as an MIS for TLE.

Methods: A consecutive case series of FATLs for ATL was conducted between 2020 and 2022. FATL was scheduled after standard presurgical evaluations of TLE and applied the same criteria as standard ATL. Seizure outcomes were categorized by Engel classifications, with at least 2 years of follow-up.

Results: Forty-nine patients with TLE who underwent FATL were included in the case series. The mean follow-up duration was 31.9 (range 24-42) months. Freedom from disabling seizures (Engel class I) occurred in 36 patients (73.5%) and significant improvement (Engel class I-II) occurred in 44 (89.8%) after surgery. The rate of complete freedom from all seizures (Engel class Ia) was 77.6% at 1 year after surgery and 69.4% at 2 years. No deaths or permanent morbidities after FATL were recorded. The complication rate was 2.0%.

Conclusions: FATL incorporates a change from anatomical resection to functional disconnection without brain shift. As a keyhole surgery, the FATL incision is barely visible, with a better cosmetic appearance than ATL. FATL has the MIS quality as well as excellent seizure outcomes similar to those of ATL.