SEEG-guided thermocoagulations: a palliative treatment of nonoperable partial epilepsies

Intracranial stereotactic EEG recordings (SEEG) in presurgical epilepsy assessment are currently carried out in our department. The SEEG method generally used for exploration can also be used to perform radiofrequency thermocoagulations (RFTC) of the epileptic foci. To assess the indications of the RFTC procedure in the therapeutic arsenal of drug-resistant epilepsies, we report the results obtained in 41 patients to whom RFTC was proposed as a first therapeutic step before surgery or as a palliative treatment when surgery was not possible.

RFTC were produced by applying a 50-volt, 110 mA current, during 10-30 seconds within the epileptogenic zone, as identified by the SEEG investigation. Two to 31 RFTC (mean, 12) were performed per patient. The median follow-up was 19 months (range: 4 to 72).

Twenty patients (48.7%) experienced a seizure frequency decrease of at least 50%, which was over 80% in eight of them. One patient was seizure-free. The tolerance was excellent. A total of 67% of the 21 patients presenting a cortical development malformation benefited from RFTC (p = 0.052). In the group of noneligible patients for resective surgery (n = 13), six were responders to SEEG-guided RFTC and one of them was seizure-free.

This study suggests that stereotactic EEG-guided radiofrequency thermocoagulations can be proposed only as a palliative procedure, able to bring a substantial improvement of seizure frequency, to drug-resistant patients with epilepsy for whom conventional resection surgery is risky or contraindicated on the basis of invasive presurgical evaluation.