Surgical treatment for refractory epilepsy

Current state of the art of traditional and minimal invasive epilepsy surgery approaches

Introduction

Open resective surgery remains the main treatment modality for refractory epilepsy, but is often considered a last resort option due to its invasiveness.

Research question

This manuscript aims to provide an overview on traditional as well as minimally invasive surgical approaches in modern state of the art epilepsy surgery.

Materials and methods

This narrative review addresses both historical and contemporary as well as minimal invasive surgical approaches in epilepsy surgery. Peer-reviewed published articles were retrieved from PubMed and Scopus. Only articles written in English were considered for this work. A range of traditional and minimally invasive surgical approaches in epilepsy surgery were examined, and their respective advantages and disadvantages have been summarized.

Results

The following approaches and techniques are discussed: minimally invasive diagnostics in epilepsy surgery, anterior temporal lobectomy, functional temporal lobectomy, selective amygdalohippocampectomy through a transsylvian, transcortical, or subtemporal approach, insulo-opercular corticectomies compared to laser interstitial thermal therapy, radiofrequency thermocoagulation, stereotactic radiosurgery, neuromodulation, high intensity focused ultrasound, and disconnection surgery including callosotomy, hemispherotomy, and subpial transections.

Discussion and conclusion

Understanding the benefits and disadvantages of different surgical approaches and strategies in traditional and minimal invasive epilepsy surgery might improve the surgical decision tree, as not all procedures are appropriate for all patients.

Screening of Risk Factors for Poor Prognosis in Patients with Refractory Epilepsy Secondary to Encephalomalacia

Objective

The study was aimed at screening the independent prognostic risk factors for refractory epilepsy associated with encephalomalacia (REAE).

Methods

Patients with REAE treated in the First People's Hospital of Linping District from January 2018 to December 2019 were selected. The prognosis was represented by Engel grading. Clinical data of the patients were collected, including age, sex, BMI, lesion sites, number of lesion sites, lesion size, seizure frequency, epilepsy type, and treatment methods. Independent risk factors for poor prognosis were screened by logistic regression analysis. The receiver operating characteristic curve (ROC) was used to evaluate the prognostic efficacy of independent risk factors.

Results

A total of 48 patients were included in this study, including 31 patients (64.58%) in the good prognosis group and 17 patients (35.42%) in the poor prognosis group. The mean age of the poor prognosis group was higher than that of the good prognosis group (P = 0.002). The proportion of patients with multisite lesions in the poor prognosis group was higher than that in the good prognosis group (P = 0.016). The proportion of patients with cerebral malacia lesion diameter ≥ 3 cm in the poor prognosis group was higher than that in the good prognosis group (P = 0.002). The proportion of patients with attack frequency ≥ 2 times/month in the poor prognosis group was higher than in the good prognosis group (P = 0.002). The proportion of patients receiving surgical treatment in the poor prognosis group was lower than that in the good prognosis group (P < 0.001). Age, number of lesion sites, size of encephalomalacia, and seizure frequency were independent risk factors for the prognosis of patients with REAE (OR > 1, P < 0.05). Surgical treatment was an independent protective factor associated with the prognosis of patients with REAE (OR < 1, P < 0.05). The area under the ROC curve of surgical treatment was 0.83 (P = 0.004). The area under the ROC curve of the size of encephalomalacia was 0.72 (P = 0.008). There was a positive correlation between age and size of encephalomalacia and Engel grade (r > 0, P < 0.05). Surgical treatment was negatively correlated with Engel grade (r < 0, P < 0.05). The number of lesion sites and seizure frequency had no significant correlation with Engel (P > 0.05). The proportion of Engel I patients treated with surgery was higher than that treated with drugs (P = 0.001). The ratio of Engel III and IV patients treated with surgery was lower than that treated with medications (P < 0.05).

Conclusion

Age, number of lesion sites, size of encephalomalacia, and seizure frequency are independent risk factors for the prognosis of patients with REAE. Surgical treatment is an independent prognostic factor for patients with REAE. Surgical treatment can significantly improve patient outcomes.

Early Prediction of Refractory Epilepsy in Children Under Artificial Intelligence Neural Network

In order to realize the early prediction of refractory epilepsy in children, data preprocessing technology was used to improve the data quality, and the detection model of refractory epilepsy in children based on convolutional neural network (CNN) was established. Then, the data in the epilepsy electroencephalography (EEG) signal public data set was used for model training and the diagnosis of refractory epilepsy in children. Moreover, back propagation neural network (BPNN), support vector machine (SVM), XGBoost, gradient boosting decision tree (GBDT), AdaBoost algorithm were introduced for comparison. The results showed that the early prediction accuracy of BP, SVM, XGBoost, GBDT, AdaBoost, and the algorithm in this study for refractory epilepsy in children were 0.745, 0.778, 0.885, 0.846, 0.874, and 0.941, respectively. The sensitivities were 0.81, 0.826, 0.822, 0.84, 0.859, and 0.918, respectively. The specificities were 0.683, 0.696, 0.743, 0.792, 0.84, and 0.905, respectively. The accuracy was 0.707, 0.732, 0.765, 0.802, 0.839, and 0.881, respectively. The recall rates were 0.69, 0.716, 0.753, 0.784, 0.813, and 0.877, respectively. F1 scores were 0.698, 0.724, 0.759, 0.793, 0.826, and 0.879, respectively. Through the comparisons of the above six indicators, the algorithm proposed in this study was significantly higher than other algorithms, suggesting that the proposed algorithm was more accurate in early prediction of refractory epilepsy in children. Analysis of the EEG characteristics and magnetic resonance imaging (MRI) images of refractory epilepsy in children suggested that the MRI images of patients' brains under this algorithm had obvious characteristics. The reason for the prediction error of the algorithm was that the duration of epilepsy was too short or the EEG of the patient didn't change notably during the epileptic seizure. In summary, the prediction method of refractory epilepsy in children based on CNN was accurate, which had broad adoption prospects in assisting clinicians in the examination and diagnosis of refractory epilepsy in children.

microRNA-139-5p confers sensitivity to antiepileptic drugs in refractory epilepsy by inhibition of MRP1

Aim

Drug resistance is an intractable issue urgently needed to be overcome for improving efficiency of antiepileptic drugs in treating refractory epilepsy. microRNAs (miRNAs) have been proved as key regulators and therapeutic targets in epilepsy. Accordingly, the aim of the present study was to identify a novel differentially expressed miRNA which could improve the efficiency of antiepileptic drugs during the treatment of refractory epilepsy.

Methods and Results

Serum samples were collected from children with refractory epilepsy. An in vivo refractory epilepsy model was developed in SD rats by electrical amygdala kindling. We identified that miR‐139‐5p was decreased and multidrug resistance‐associated protein 1 (MRP1) was remarkably upregulated in the serum samples from children with refractory epilepsy and the brain tissues from rat models of refractory epilepsy. After phenobarbitone injection in rat models of refractory epilepsy, the after discharging threshold in kindled amygdala was detected to screen out drug‐resistant rats. Dual‐luciferase reporter gene assay demonstrated that MRP1 was a target of miR‐139‐5p. In order to evaluate the effect of miR‐139‐5p/MRP1 axis on drug resistance of refractory epilepsy, we transfected plasmids into the hippocampus of drug‐resistant rats to alter the expression of miR‐139‐5p and MRP1. TUNEL staining and Nissl staining showed that miR‐139‐5p overexpression or MRP1 downregulation could reduce the apoptosis and promote survival of neurons, accompanied by alleviated neuronal damage.

Conclusion

Collectively, these results suggest an important role of miR‐139‐5p/MRP1 axis in reducing the resistance of refractory epilepsy to antiepileptic drugs.