Abstracts

Rationale: Mesial temporal lobe epilepsy (MTLE) is the most surgically amenable epilepsy diagnosis and the results of epilepsy surgery are clearly superior to prolonged medical therapy. Stereotactic radiofrequency amygdalohippocampectomy (SAHE) is an alternative therapy of MTLE. In our hospital SAHE has been used since 2004. We produced lesions from the occipital access with a single trajectory in the long axis of amygdalohippocampal complex (AHC) using the probe with a flexible active tip. The aim of this study was to correlate volume reduction of the target structures / the hippocampus, the amygdala, entorhinal (EC) and perirhinal (PRC) cortices/ with the clinical seizure outcome. Methods: We included 26 consecutive patients, who underwent SAHE using Leksell stereotactic system. MRI volumetry of hippocampus, amygdala, EC and PRC was performed 1 year after the procedure. The clinical outcome was assessed 1 and 2 years after the procedure according to Engel s Classification. Results: 21 patients had left-sided and 5 patients right-sided MTLE. No serious adverse events occurred after the procedure. One year after procedure, the hippocampal volume decreased by 55.5 18.0%, the amygdalar volume decreased by 49.2 16.8 %, PRC volume decreased by 45.9 16.7% and the size of EC decreased by 55.5 19.6 %. Clinically, 1 year after the procedure 19 (73%) patients were classified as Class I, 5 (19%) patients as Class II and the treatment failed in 2 patients. The latter 2 patients were re-operated and excluded from the second year of the clinical follow-up. Two years after the procedure, 24 patients were evaluated; 19 (79%) of them were classified as Class I and only 5 (21%) patients as Class II. No statistically significant relation of target structures volume reduction and of the clinical outcome was found. Conclusions: We have not found any significant relation between morphological changes and clinical outcome. According to our data, it seems that the attempt to make (stereotactic) MTLE surgery as radical as technically possible must not be tenable. SAHE caused only partial destruction of the target structure, but the clinical seizure outcome is very promising, two years after the procedure is comparable with classical surgical approaches.