Abstracts

Rationale: There is currently no resective (potentially curative) surgical option useful in this patient population. Palliative procedures such as callosotomy (Cx), vagus nerve stimulation (VNS) or deep brain stimulation have been offered. We compared the outcome after Cx or VNS in two consecutive prospective cohorts of patients with secondary generalized epilepsy. Methods: Twenty patients were submitted to callosotomy from 2006 to 2007 (Group 1); 20 additional patients were submitted to VNS from 2008 to 2009 (Group 2). They had secondary generalized epilepsy of the Lennox-Gastaut or Lennox-like type. They were submitted to a neurological interview and examination, interictal and ictal video-EEG, high resolution 1.5T MRI, and cognitive and quality of life evaluations. Two-year post-operative follow-up results were considered for each patient. Results: Final mean stimuli intensity was 3.0mA in Group 2 patients. There were 10% of seizure-free patients in Group 1, and none in Group 2. Ten percent of Group 1 patients were non-responders, while 16% of Group 2 did so. Improvement in attention and quality of life was noted in 85% of both Group 1 and 2 patients. Rupture of secondary bilateral synchrony was noted in 85% of Group 1 patients; there was no EEG modification after VNS in group 2. Both procedures were effective regarding the control of atypical absences and generalized tonic-clonic seizures. Both procedures were not effective in controlling tonic seizures. Callosotomy was very effective in reducing atonic seizure's frequency, while VNS was ineffective. On the other hand, callosotomy was not effective in reducing myoclonic seizures, while VNS did so. Conclusions: Callosotomy might be preferred as primary treatment in kids with Lennox-Gastaut syndrome and no specific findings on MRI if atonic seizures prevail in the patient's clinical picture; when myoclonic seizures prevail this might hold true in favor of VNS. When atypical absence or generalized tonic-clonic seizures are the main concern, although both procedures carry similar effectiveness, VNS should be considered as an initial approach taking into account the adverse event profile. Patients should be advised that both procedures are not very effective in the treatment of tonic seizures.