Despite former publications no clear seizures could be reproduced but it was possible to establish focal EPs, which proved to be a reliable marker for epileptic activity. Local antiepileptic therapy with VPA has shown efficacy in decreasing EP frequency.
Purpose. In neocortical epilepsies not satisfactorily responsive to systemic antiepileptic drug therapy, local application of antiepileptic agents onto the epileptic focus may enhance treatment efficacy and tolerability. We describe the effects of focally applied valproate (VPA) in a newly emerging rat model of neocortical epilepsy induced by tetanus toxin (TeT) plus cobalt chloride (CoCl2). Methods. In rats, VPA (n = 5) or sodium chloride (NaCl) (n = 5) containing polycaprolactone (PCL) implants were applied onto the right motor cortex treated before with a triple injection of 75 ng TeT plus 15 mg CoCl2. Video-EEG monitoring was performed with intracortical depth electrodes. Results. All rats randomized to the NaCl group died within one week after surgery. In contrast, the rats treated with local VPA survived significantly longer (P < 0.01). In both groups, witnessed deaths occurred in the context of seizures. At least 3/4 of the rats surviving the first postoperative day developed neocortical epilepsy with recurrent spontaneous seizures. Conclusions. The novel TeT/CoCl2 approach targets at a new model of neocortical epilepsy in rats and allows the investigation of local epilepsy therapy strategies. In this vehicle-controlled study, local application of VPA significantly enhanced survival in rats, possibly by focal antiepileptic or antiepileptogenic mechanisms.
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Removal of the seizure focus, either by resection or by laser thermal ablation, has a high chance to result in seizure freedom in well-selected patients with focal drug-resistant epilepsy. Vagus nerve stimulation and deep brain stimulation are palliative approaches, which aim to reduce the number and severity of epileptic seizures. In older patients there seems to be an overall reluctance with respect to all epilepsy surgery procedures. In this context, "older" means patients with an age of 50 years and above. In this article, we assess if there are clinically relevant differences with respect to seizure outcome and complications in older patients compared to younger patients when using the different epilepsy surgery approaches. Overall, available and reliable data are sparse and there are hardly any studies of high quality. Most data with almost 700 patients are on resective surgery, predominantly from retrospective monocentric studies on temporal lobe epilepsy. In summary, it seems that the rates of seizure freedom and complications do not differ significantly in older patients compared to younger patients; however, it cannot be ruled out that in the group of older patients rather clear and straightforward cases have been resected. For thermal ablation procedures, no specific data on older patients exist. The minimally invasive approach with few complications, however, may be interesting particularly for older patients. With respect to vagus nerve stimulation and deep brain stimulation, the available data do not give any evidence for differences in efficacy and safety in older vs. younger patients.
ZusammenfassungDie Entfernung des Anfallsfokus – durch Resektion oder Laserthermoablation – stellt bei ausgesuchten Patienten mit fokaler pharmakoresistenter Epilepsie eine Therapie mit guter Aussicht auf Anfallsfreiheit bei geringen Risiken dar. Die Vagusnerv- und die tiefe Hirnstimulation sind palliative Verfahren, die die Häufigkeit und die Schwere epileptischer Anfälle reduzieren sollen. Bei älteren Patienten besteht eine allgemeine Zurückhaltung hinsichtlich aller epilepsiechirurgischen Verfahren, „älter“ bedeutet in diesem Kontext in der Regel ein Lebensalter jenseits von 50 Jahren. In dieser Arbeit wird untersucht, ob es im Vergleich von älteren zu jüngeren Patienten relevante Unterschiede bezüglich Anfallsprognose und Komplikationsraten bei den verschiedenen epilepsiechirurgischen Verfahren gibt. Insgesamt ist die Datenlage dünn, es gibt kaum qualitativ hochwertige Studien. Die meisten Daten liegen für resektive Verfahren vor. Hier sind fast 700 ältere Patienten publiziert, meist in retrospektiven, monozentrischen Studien zu Temporallappenepilepsien. Zusammengefasst unterscheidet sich die Rate an Anfallsfreiheit und die an Komplikationen bei älteren Patienten nicht von der bei jüngeren Patienten. Es ist aber nicht auszuschließen, dass in der Gruppe der älteren Patienten bevorzugt besonders klare und erwartbar unkomplizierte Fälle reseziert wurden. Bei den Thermoablationsverfahren liegen keine Daten für ältere Patienten vor. Der minimal-invasive Ansatz könnte jedoch bei geringerer Komplikationsrate gerade für die Gruppe der Älteren interessant sein. Bei der Vagusnerv- und der tiefen Hirnstimulation deuten die wenigen verfügbaren Daten nicht auf Unterschiede zwischen älteren und jüngeren Patienten in Bezug auf Wirksamkeit und Sicherheit hin.
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