Introduction: Ipsilateral mesial temporal atrophy is a well-known prognostic indicator of temporal lobe resection. The significance of atrophy of other structures in these patients is less clear.
Methods: Structure-based quantification of the MRIs of 48 epilepsy patients undergoing resective surgery and 48 age- and sex-matched normal controls was performed using an automated cortical parcellation and subcortical segmentation algorithm. Chi-square testing of structural atrophy status to seizure control was then performed.
Results: Compared to patients with preserved putaminal volume, patients with putaminal atrophy ipsilateral or contralateral to the side of resection had significantly higher seizure-free outcome. Patients with preserved posterior corpus callosum had significantly higher seizure-free outcome compared to those with posterior corpus callosal atrophy. Patients with preserved pars triangularis and lateral occipital, medial orbitofrontal, and rostral middle frontal cortices contralateral to the side of resection had more seizure-free outcomes than patients with thinning of these structures. Subgroup analysis of cortical thickness in the setting of subcortical structural atrophy revealed that more patients were seizure free who had putaminal atrophy and preserved medial orbitofrontal cortex contralateral to the resected side. Patients with preserved pars triangularis and medial orbitofrontal and rostral middle frontal cortices contralateral to the resected side in the setting of contralateral putaminal atrophy had better outcomes. On the other hand, patients had worse seizure control if atrophied posterior corpus callosum was observed in the setting of lateral occipital and medial orbitofrontal cortical thinning contralateral to the side of resection.
Conclusions: Putaminal atrophy and preserved posterior corpus callosum, as well as preserved par triangularis and lateral occipital, medial orbitofrontal, and rostral middle frontal cortices contralateral to the side of resection were suggestive prognostic indicators for seizure-free outcome. Larger studies are needed to determine the relative contribution of each structure to seizure control.
Patient Care: Identifying prognostic factors of resective epilepsy surgery will allow us to refine patient selection and improve outcome.
Learning Objectives: By the conclusion of this session, participants should be able to discuss the relationship of structural atrophy to resective surgical outcome.