Predictive factors of long-term outcomes of surgery for mesial temporal lobe epilepsy associated with hippocampal sclerosis.

OBJECTIVE: The reasons for failure of surgical treatment for mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS) remain unclear. This retrospective study analyzed seizure, cognitive, and psychiatric outcomes, searching for factors associated with seizure relapse or cognitive and psychiatric deterioration after MTLE-HS surgery.

METHODS: Seizure, cognitive, and psychiatric outcomes were reviewed after 389 surgeries performed between 1990 and 2015 on patients aged 15-67 years at a tertiary center. Three surgical approaches were used: anterior temporal lobectomy (ATL; n = 209), transcortical selective amygdalohippocampectomy (SAH; n = 144), and transsylvian SAH (n = 36).

RESULTS: With an average follow-up of 8.7 years (range = 1.0-25.2), seizure outcome was classified as Engel I in 83.7% and Engel Ia in 57.1% of patients. The histological classification of HS was type 1 for 75.3% of patients, type 2 for 18.7%, and type 3 for 1.2%. Two factors were significantly associated with seizure recurrence: past history of status epilepticus and preoperative intracranial electroencephalographic recording. In contrast, neither HS type, the presence of a dual pathology, nor surgical approach was associated with seizure outcome. Risk of cognitive impairment was 3.12 (95% confidence interval = 1.27-7.70), greater in patients after ATL than in patients after transcortical SAH. A presurgical psychiatric history and postoperative cognitive impairment were associated with poor psychiatric outcome.

SIGNIFICANCE: The SAH and ATL approaches have similar beneficial effects on seizure control, whereas transcortical SAH tends to minimize cognitive deterioration after surgery. Variation in postsurgical outcome with the class of HS should be investigated further.