The Efficacy Of VNS In Patients With Pharmacoresistant Epilepsy Of Temporal Versus Extra-Temporal Locations.

摘要

Objective: Evaluating the effectiveness of VNS therapy in patients with refractory epilepsy of temporal versus extra-temporal locations.Methods: Retrospective record review of 31 patients with refractory epilepsy was carried out. Patients were divided into TLE group and extra TLE group based on the epileptogenic foci. Changes in seizures frequency was assessed at one year following VNS implant. Those with >50% reduction in seizures frequency from the base line were considered responders to VNS therapy.Results: Out of 31 patients one died from unrelated cause and another asked their device to be removed due to AEs. There were 9 patients with TLE and 20 with extra TLE. There were no significant differences in demographic characteristics or seizures frequency (TLE 1-450/month and extra TLE 3-900/month). All the patients were taking an average of 2- 5 AEDs a day. No significant differences were observed in responder rate between groups at one year (p= 0.88; 66% in TLE and 55% in extra-TLE).Conclusion: The study demonstrates that VNS is an effective therapy in epilepsy patients irrespective of thelocation of the epileptogenic foci. Introduction Epilepsy is well controlled in 60% to 70% of patients with seizures due to recent advances in AEDs therapy, which provides several options for physicians who treat patients with epilepsy. However, about one third of patients has drug resistant epilepsy or are unable to tolerate medications due to adverse effects (1, 2). In this group of patients with drug resistant epilepsy generally the accepted non-medical therapy is limited to ketogenic diet, resective epilepsy surgery and VNS. The ketogenic diet may not be helpful or practical in adults, and a considerable proportion of patients with pharmacoresistant partial onset seizures is not a candidate for or is opposed to intracranial surgery. For such patients, VNS may be an alternative therapeutic option (3, 4) The FDA has approved VNS since 1997 for use as an adjunctive therapy to reduce the frequency of seizures in adults and adolescents over 12 years of age with partial onset seizures, and who are refractory to AEDs. Since 1997 the VNS has been an alternative treatment for refractory epilepsy, and the long-term outcome of VNS treatment has been reported with variable results in a number of studies (5, 6). However, it is unclear whether VNS is equally effective irrespective of the location of the epileptic focus. Recently, it has been suggested that VNS is more efficacious in frontal than temporal lobe epilepsy (7). In this study we aimed to evaluate the efficacy of VNS in patients with partial seizure of temporal lobe versus extra-temporal origin. Methods The medical records of all patients implanted with VNS between 1998 and 2001 were reviewed.(Refer to prior study of long-term outcome of VNS; JCN 2008). All the patients were admitted to EMU for phase 1 presurgical evaluation. The evaluation consisted of detailed history, physical examination, interictal EEG, video EEG for ictal recording and clinical semiology, MRI of the brain and neuropsychology test. All patients were being treated with 2 to 4 AEDs. Patients were offered VNS therapy if their surgical evaluation indicated that they would not benefit from resective surgery. The record review collected patients’ data regarding seizures frequency before and one year following VNS implantation. The patients were divided into TLE and extra-TLE groups based on the epileptogenic foci. Changes in seizures frequency was assessed at one year following VNS implant. Patients with >50% reduction in seizure frequency were considered responder to VNS therapy. Statistical analyses (Student t test) were conducted on seizure outcome and the responder rate for any significant difference between groups (P<0.05). Results Thirty-one patients were implanted with VNS. Out of 31 patients one died of unrelated cause, and another patient asked for the device to be removed due to adverse effects, such as pain in he