[Extra-hippocampal temporal lesions inducing symptomatic drug-resistant epilepsies. Which surgical procedure?]

In partial symptomatic epilepsy due to discrete brain lesion, total removal of the epileptogenic lesion generally yields major reduction of seizures, achieved in 85% of the patients. However, prognosis is worse in patients with symptomatic temporal lobe epilepsy. Implication of the temporo-mesial structures in the seizures genesis is generally considered. Careful electroclinical and radiological analysis can provide useful but insufficient information. In order to evaluate the criteria we used to guide our surgical strategy, we analyzed retrospectively a series of 47 patients with drug-resistant symptomatic extra hipocampic temporal epilepsy surgically treated either by isolated lesionectomy (group 1, n=17) or by resection of temporo-mesial structures and associated lesionectomy (group 2, n=30). Patients with extrahippocampal lesions and hippocampal sclerosis (dual pathology) were excluded from this study. With a mean follow-up of 72 months, overall results showed that 84% of group 2 patients (Engel's grade Ia) were seizure-free compared with only 47% of group 1 patients. Statistical analysis showed that the type of surgical procedure was the main prognostic factor. In conclusion, the optimal surgical procedure cannot be defined only with the criteria usually retained for temporo-mesial involvement in seizure genesis. Taking into account the prognostic value of such implication, although complex, is of paramount importance. Our results could be explained by the presence of an acquired dual functional pathology.