Michal Ryzí

Long‐term vagus nerve stimulation in children with focal epilepsy

The aim of the study was to evaluate the long‐term efficacy and hospitalization rates in children with refractory focal epilepsy treated by vagus nerve stimulation.

Effect of chronic vagal nerve stimulation on interictal epileptiform discharges

We evaluated the effect of vagus nerve stimulation (VNS) on interictal epileptiform discharges (IEDs) in 32 epileptic patients (18 females; 14 males) with an average age of 42.2+/-11.4 years, all of whom had been suffering from epilepsy for an average of 29.2+/-14.5 years. All of the patients had received VNS for 5 years. The first EEG was performed prior to the initiation of stimulation; the second EEG was performed at the 5-year follow-up visit. The duration of each EEG was 30 min. We compared these two EEGs in terms of the number of IEDs present in each patient and correlated them to other variables. The average total number of IEDs during EEG and the total number of seconds in which IEDs were present decreased significantly after 5 years of stimulation from 97.3+/-106.9 resp. 80.6+/-86.1 to 49.4+/-94.0 resp. 37.8+/-65.0. Although there was no positive correlation between the reduction of IEDs and the percent of seizure reduction, we found a greater decrease of IEDs in patients who responded to VNS in comparison to those who did not. The decrease of IEDs was more pronounced in patients suffering from temporal lobe epilepsy than in patients suffering from extratemporal epilepsy. No other significant correlations were found. VNS reduced IEDs in patients chronically simulated for epilepsy. The reduction of IEDs was greater in patients who responded to VNS and in patients suffering from temporal lobe epilepsy.

Long-term outcomes in patients after epilepsy surgery failure.

PURPOSE The primary aim of this study was to analyze the long-term outcomes of patients who were classified as Engel IV one year after resective epilepsy surgery. The secondary objectives were to evaluate the effectiveness of different treatment options and to examine the reasons that the patients did not undergo resective reoperation. METHODS Our study was designed as a retrospective open-label investigation of the long-term outcomes of 34 patients (12% of all surgically treated patients) who were classified as Engel IV one year after epilepsy surgery. RESULTS At the last follow-up visit (average of 7.6 ± 4.2 years after surgery), 12 of the 34 examined patients (35.3%) were still classified as Engel IV; 22 of the 34 patients (64.7%) were improved (Engel I-III). Of the 34 patients, 8 (23.5%) achieved an excellent outcome, classified as Engel I, 3 patients (8.8%) were classified as Engel II, and 11 patients (32.4%) as Engel III. The seizure outcome in the patients classified as Engel I was achieved by resective reoperation in 4; by a change in antiepileptic medication in 3 patients; and by vagus nerve stimulation (VNS) in 1 patient. The seizure outcome of Engel II was achieved by a change in antiepileptic medication in all 3 patients. Of the 34 patients, a total of 6 (17.6%) underwent resective reoperation only. The major reasons for this were the absence of a plausible hypothesis for invasive re-evaluation, the risk of postoperative deficit, and multifocal epilepsy in the rest of patients. CONCLUSION Although the reoperation rate was relatively low in our series, we can achieve better or even excellent seizure outcomes using other procedures in patients for whom resective surgery initially failed.

Long‐term approach to patients with postsurgical seizures

The main purpose of the study was to analyze the long‐term outcomes and therapeutic approaches for patients with seizures within the first year after surgery. The secondary aim of the study was to evaluate the relationship between 1‐year outcome and long‐term outcome and choice of therapy.

Response to “Failed epilepsy surgery: It is not too late”

Thank you for the opportunity to respond to the letter from Englot et al. regarding our recent publication (Ryzi et al., 2015). We agree that there is a need for further detailed investigation into the reasons for surgical failure, and for seeking possibilities for re-operations and other treatment options after surgical failure. The reasons for the failures in our group were incomplete resections of the seizure on set zone in 21 patients (61.8 %) and additional epileptogenic regions in 13 patients (38.2 %) — five patients with bitemporal findings, six without MRI lesions in preoperative assessment, and two with focal cortical dysplasia type I in histology.