Abstracts

Intracranial EEG recordings in presurgical epilepsy assessment are done in our unit using stereotactically implanted depth electrodes. Five years ago, we explored use of these electrodes to produce RFTC lesions inside the epileptogenic area. We report the results in 42 patients., 42 consecutive patients explored by video-SEEG recordings were enrolled in this study between June 2001 and February 2006. RFTCs were produced by inducing a Joule effect between electrode contacts where discharge onsets had been recorded. Four to 31 lesions (mean, 12.5) were performed per patient. The epileptic focus (EF) was located in the frontal (8 patients), occipital (7), insular (4), parietal (3) and temporal (20) lobe. Several etiologies were found: cortical dysplasia (CD) (21), hippocampal sclerosis (4), periventricular heteropia (PH) (3), posttraumatic focal atrophy (1) and cryptogenic epilepsy (13). The results were evaluated on the decrease in the number of seizures: good outcome (GO, [gt]70%) and using a self-administered questionnaire, each patient estimated the presence (a) or absence (b) of improvement in their quality of life (QL)., The GO rate 1 month after the intervention (57%) decreased to 35% at the 6-month evaluation and then stabilized. The QL evaluation showed comparable mean results (a = 38%) but rose to 66% on the subgroup of patients who were inoperable after SEEG exploration.
The GO rate was positively correlated with:
1) anterior location of the EF: 75, 37 and 33% of GO for insular, frontal and temporal lobe epilepsy, respectively, with no change for parietal and occipital epilepsy.
2) the etiology, with the best results for symptomatic epilepsy (37 and 33% GO in CD and PH, respectively) vs 23% GO in cryptogenic forms.
No general or neurological complication occurred during the procedures other than two transient deficits (paresthetic sensations in the mouth and mild apraxia of the hand).
20 unsatisfied patients had a secondary classical intervention (19 now in Engel class 1 and 1 in class 2), This study reports the results at 5 years of RFTC treatment given to 42 epileptic patients during SEEG exploration. This procedure is:
1) sure: complications are rare, minor and always reversible despite treatment often targeting high-value functional cortical and/or inaccessible areas
2) effective: benefit in terms of seizure control concerns 1/3+ patients with GO maintained long term from the 6th month after treatment
3) offers improvement in quality of life, especially for the 2/3 of patients considered inoperable after invasive exploration
4) no surgical burden on prognosis: 19/20 patients operated after RFTC failure are in Engel class 1
These results changed our SEEG exploration strategy by combining diagnosis and therapeutic potential until now unknown with this technique., (Supported by HCL.)