Anterior thalamic nucleus deep brain Stimulation (DBS) for drug-resistant complex partial seizures (CPS) with or without generalization: long-term evaluation and predictive outcome

Background: Drug-resistant epileptic patients account for 40 % of cases of epilepsy. Consequently, specific therapeutic options could be surgical resection or, if not indicated, deep brain stimulation (DBS). The aim of this study is to review data from patients affected by drug-resistant complex partial epilepsy with or without generalization treated by anterior thalamic nucleus (AN) DBS to evaluate the efficacy and potential future applications of this approach as a standard method for palliative seizure control. Methods: Six patients affected by drug-resistant complex partial seizures underwent AN DBS from March 2007 to February 2011. The preoperative tests consisted of electroencephalography (EEG), video EEG, morphologic and functional magnetic resonance imaging (MRI), non-acute positron emission tomography (PET), neuropsychological evaluation, Liverpool seizure scale, and Quality Of Life In Epilepsy (QOLIE). These tests and a seizure diary were also administered during a follow-up of at least 3 years. Results: The improvement in terms of decrease of seizures was more than 50 % in patients affected by complex partial seizures strictly related to limbic system origin. The amelioration was unsatisfactory for patients having anatomical lesions outside the limbic structures with evidence of late diffusion in limbic areas. One patient died 40 days after surgery for reasons not concerned with DBS. Conclusions: Although the limited number of enrolled patients limits the reliability of data, the results are in accordance with those found in the recent literature and deserve to be considered for further studies regarding real efficacy, indications, stimulation parameters, side effects, and complications.