Stereotactic radiofrequency amygdalohippocampectomy for the treatment of mesial temporal lobe epilepsy: correlation of MRI with clinical seizure outcome.

SUMMARY: Stereotactic radiofrequency amygdalohippocampectomy (AHE) has been reintroduced as an alternative treatment of mesial temporal lobe epilepsy. The aim of this study was to describe MRI changes after stereotactic AHE and to correlate the hippocampal and amygdalar volumes reduction with the clinical seizure outcome. Eighteen patients after stereotactic AHE were included. Volumetry was calculated from pre-operative MRI and from MRI obtained 1 year after the operation. The clinical outcome was examined 1 and 2 years after the treatment. Hippocampal volume decreased by 54+/-19%, and amygdalar volume decreased by 49+/-18%. One year after the procedure, 13 (72%) patients were classified as Engel's Class I (9 as Class IA), 4 (22%) patients as Class II and 1 (6%) patient as Class III. Two years after the operation, 14 patients (82%) were classified as Class I (7 as Class IA) and 3 patients (18%) as Class II. We found 3 surgical complications after the procedure: one small subdural hematoma, and twice a small electrode tip left in operation field (these patients were excluded from the study). In 3 patients, temporary meningeal syndrome developed. Results of radiofrequency AHE are promising. The volume reduction of target structures after AHE is significantly related to the clinical outcome.