Optimal Surgical Extent for Memory and Seizure Outcome in Temporal Lobe Epilepsy

Daichi Sone, Maria Ahmad, Pamela J Thompson, Sallie Baxendale, Sjoerd B Vos, Fenglai Xiao, Jane de Tisi, Andrew W McEvoy, Anna Miserocchi, John S Duncan, Matthias J Koepp, Marian Galovic

Research output: Contribution to journalArticlepeer-review

5 Citations (Web of Science)


OBJECTIVE: Postoperative memory decline is an important consequence of anterior temporal lobe resection (ATLR) for temporal lobe epilepsy (TLE), and the extent of resection may be a modifiable factor. This study aimed to define optimal resection margins for cognitive outcome while maintaining a high rate of postoperative seizure freedom.

METHODS: This cohort study evaluated the resection extent on postoperative structural MRI using automated voxel-based methods and manual measurements in 142 consecutive patients with unilateral drug refractory TLE (74 left, 68 right TLE) who underwent standard ATLR.

RESULTS: Voxel-wise analyses revealed that postsurgical verbal memory decline correlated with resections of the posterior hippocampus and inferior temporal gyrus, whereas larger resections of the fusiform gyrus were associated with worsening of visual memory in left TLE. Limiting the posterior extent of left hippocampal resection to 55% reduced the odds of significant postoperative verbal memory decline by a factor of 8.1 (95% CI 1.5-44.4, p = 0.02). Seizure freedom was not related to posterior resection extent, but to the piriform cortex removal after left ATLR. In right TLE, variability of the posterior extent of resection was not associated with verbal and visual memory decline or seizures after surgery.

INTERPRETATION: The extent of surgical resection is an independent and modifiable risk factor for cognitive decline and seizures after left ATLR. Adapting the posterior extent of left ATLR might optimize postoperative outcome, with reduced risk of memory impairment while maintaining comparable seizure-freedom rates. The current, more lenient, approach might be appropriate for right ATLR. ANN NEUROL 2021.

Original languageEnglish
Pages (from-to)131-144
Number of pages14
JournalAnnals of Neurology
Issue number1
Early online date5 Nov 2021
Publication statusPublished - Jan 2022
Externally publishedYes


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