Neuropsychological outcomes of hippocampus-sparing anterior temporal lobectomy versus stereotactic laser amygdalohippocampectomy in language-dominant temporal lobe epilepsy.

Abstract

Objective: Postoperative neuropsychological deficits pose a significant challenge for temporal lobe epilepsy (TLE) surgery, particularly in the language-dominant hemisphere. Two surgical approaches have been suggested to mitigate such adverse outcomes: stereotactic laser amygdalohippocampectomy (SLAH) and hippocampus-sparing anterior temporal lobectomy (HSATL). This retrospective cohort study compares the seizure control and neuropsychological outcomes of HSATL and SLAH in language-dominant TLE.

Methods: A retrospective cohort study compared 27 patients (nine male, mean age = 35.8 years) with drug-resistant TLE and normal imaging localized to the language-dominant left temporal lobe, undergoing either HSATL (n = 22) or SLAH (n = 5) between 2014 and 2021. Comprehensive pre- and ≥1-year postoperative neuropsychological testing and imaging were performed, with seizure outcomes tracked for at least 1 year postoperatively. However, to assess the impact of mesial temporal sclerosis (MTS) on SLAH outcomes, we included seven additional patients with MTS who underwent SLAH in a secondary analysis.

Results: HSATL led to significant declines in logical memory (p = .04) despite sparing the hippocampus, which were not seen following SLAH in patients regardless of MTS status. SLAH trended toward improved semantic fluency, immediate verbal memory, and executive function despite hippocampal ablation. Including both MTS(+) and MTS(-) patients, there was a significant decline in letter fluency following SLAH (.04), with subgroup analyses demonstrating significantly greater declines in MTS(+) patients undergoing SLAH (.02). Additionally, 100% of patients undergoing SLAH achieved seizure freedom versus 72.7% following HSATL (p = .046, including MTS[+] patients) at last follow-up.

Significance: In language-dominant TLE, SLAH demonstrated comparable seizure outcomes and superior verbal memory retention compared to HSATL, albeit with greater letter fluency impairment. Preliminary findings challenge prioritizing hippocampal preservation for verbal memory function, suggesting potential cognitive advantages with SLAH specifically targeting mesial structures while maximally preserving cortical structures and white matter tracts critical for language networks. However, this intervention may negatively impact letter fluency, suggesting careful preoperative screening and discussion.