Antiepileptic Drug Withdrawal after Surgery in Children with Focal Cortical Dysplasia: Seizure Recurrence and Its Predictors

Postoperative interictal epileptiform discharges predict seizure recurrence after antiepileptic drug withdrawal regardless of concordance with surgical site

Objective

The study aimed to explore the association between the site of interictal epileptic discharges (IEDs) on postoperative electroencephalogram (EEG) and seizure recurrence after antiepileptic drug (AED) withdrawal. The study hypothesizes that the concordance of IED sites with surgical sites indicates incomplete resection of epileptic focus, while non-concordance of IED sites with surgical sites indicates postoperative changes or cortical stimulation. The former has a higher risk of seizure recurrence.

Methods

We retrospectively analyzed the postoperative EEG pattern of 182 consecutive children who underwent resection surgery. To identify the risk factors for seizure recurrence, we compared the attributes of seizure recurred and seizure-free groups by univariate and multivariate analyses. AED tapering was standardized, involving a 25% reduction in the dose of a single type of AED every 2 weeks, independent of the presurgical AED load.

Results

We attempted AED withdrawal in 116 (63.7%) children. Twenty-eight (24.1%) children experienced seizure recurrence during or after AED withdrawal. A greater number of AEDs used at the time of surgery (p=0.005), incomplete resection (p=0.001), and presence of IED on postoperative EEG (p=0.011) are predictors of seizure recurrence. The completeness of resection and seizure recurrence after AED withdrawal were related to the presence of IED on the EEG, but not to the concordance of IED with surgical sites.

Conclusion

For children with abnormal EEG, the decision to discontinue AED should be made more cautiously, regardless of the relative location of the discharge site and the surgical site.

Early antiseizure medication withdrawal and risk of seizure recurrence in children after epilepsy surgery: A retrospective study

OBJECTIVE

The timing of antiseizure medication (ASM) withdrawal in children after epilepsy surgery remains controversial and lacks recognized standards. Given the various negative effects of ASM on development in children, this study aimed to evaluate the safety and feasibility of early ASM withdrawal after epileptic resection surgery.

METHODS

We retrospectively assessed the seizure outcomes and ASM profiles of children who had undergone epileptic resection surgery between August 2015 and August 2020 and attempted ASM reduction in the early postoperative phase. Tapering the dose of ASM was attempted when children were seizure-free with no interictal epileptiform discharges (IEDs) on electroencephalogram (EEG) for at least 6 months postoperatively.

RESULTS

This study included 145 children with a median follow-up duration of 40 months. Early ASM tapering was attempted postoperatively in 99 (68.3 %) children. Postoperative ASM discontinuation was attempted in 87 (60.0 %) children. Nine (9.1 %) children experienced seizure recurrence during the ASM reduction stage, and 10 (11.5 %) experienced recurrence after ASM discontinuation. Incomplete resection (P = 0.003) and postoperative seizures before ASM tapering (P = 0.003) were independent predictors of seizure recurrence during and after early ASM withdrawal.

SIGNIFICANCE

ASM withdrawal is viable and safe to be initiated in children who are seizure-free postoperatively and have no IEDs on the scalp EEG for at least 6 months. Children with incomplete resection and postoperative seizures before ASM withdrawal are at a higher risk of seizure recurrence and may need to continue ASM for a longer period.

Withdrawal of antiseizure medications - for whom, when, and how?

INTRODUCTION

Epilepsy is a chronic disorder of the brain characterized by an enduring predisposition to generate epileptic seizures. Most patients can achieve complete seizure control (seizure freedom) with antiseizure medications (ASMs). In some of them, the withdrawal of ASMs can be considered. Guidance is required to identify patients in whom drug discontinuation can be safely attempted and to inform when and how ASM withdrawal can be done.

AREAS COVERED

In this perspective, the authors discuss the evidence on ASM withdrawal in epilepsy patients who are seizure-free and provide some suggestions on how to do it effectively in clinical practice, minimizing the risk of seizure recurrence.

EXPERT OPINION

The decision of discontinuing ASMs in epilepsy patients should rely on an accurate estimate of seizure recurrence risk. Whenever possible, such a risk should be assessed on an individual basis. The decision should also consider the psychosocial and personal consequences of seizure relapse. No robust evidence is available on the safest tapering regimen.

Lesion Detection Through MRI Postprocessing in Pathology-Proven Focal Cortical Dysplasia: Experience at a Single Institution in the Republic of Korea

BACKGROUND AND PURPOSE

Focal cortical dysplasia (FCD) is one of the most common causes of drug-resistant epilepsy, and necessitates a multimodal evaluation to ensure optimal surgical treatment. This study aimed to determine the supportive value of the morphometric analysis program (MAP) in detecting FCD using data from a single institution in Korea.

METHODS

To develop a standard reference for the MAP, normal-looking MRIs by two scanners that are frequently used in this center were chosen. Patients with drug-resistant epilepsy and FCD after surgery were candidates for the analysis. The three-dimensional T1-weighted MRI scans of the patients were analyzed as test cases using the MAP.

RESULTS

The MRI scans of 87 patients were included in the analysis. The radiologist detected abnormal findings correlated with FCD (RAD positive [RAD(+)]) in 34 cases (39.1%), while the MAP could detect FCD in 25.3% of cases. A combination of the MAP (MAP[+] cases) with interpretations by the radiologist increased the detection to 42.5% (37 cases). The lesion detection rate was not different according to the type of reference scanners except in one case. MAP(+)/RAD(-) presented in three cases, all of which had FCD type IIa. The detection rate was slightly higher using the same kind of scanner as a reference, but not significantly (35.0% vs. 22.4% p=0.26).

CONCLUSIONS

The results of postprocessing in the MAP for detecting FCD did not depend on the type of reference scanner, and the MAP was the strongest in detecting FCD IIa. We suggested that the MAP could be widely utilized without developing institutional standards and could become an effective tool for detecting FCD lesions.

Predictors of postoperative long-term seizure outcome in pediatric patients with focal cortical dysplasia type II at a German tertiary epilepsy center

OBJECTIVE

Focal cortical dysplasia (FCD) is a common cause of early-onset intractable epilepsy, and resection is a highly sufficient treatment option. In this study, the authors aimed to provide a retrospective analysis of pre- and postoperative factors and their impact on postoperative long-term seizure outcome.

METHODS

The postoperative seizure outcomes of 50 patients with a mean age of 8 ± 4.49 years and histologically proven FCD type II were retrospectively analyzed. Furthermore, pre- and postoperative predictors of long-term seizure freedom were assessed. The seizure outcome was evaluated based on the International League Against Epilepsy (ILAE) classification.

RESULTS

Complete resection of FCD according to MRI criteria was achieved in 74% (n = 37) of patients. ILAE class 1 at the last follow-up was achieved in 76% (n = 38) of patients. A reduction of antiepileptic drugs (AEDs) to monotherapy or complete withdrawal was achieved in 60% (n = 30) of patients. Twelve patients (24%) had a late seizure recurrence, 50% (n = 6) of which occurred after reduction of AEDs. A lower number of AEDs prior to surgery significantly predicted a favorable seizure outcome (p = 0.013, HR 7.63). Furthermore, younger age at the time of surgery, shorter duration of epilepsy prior to surgery, and complete resection were positive predictors for long-term seizure freedom.

CONCLUSIONS

The duration of epilepsy, completeness of resection, number of AEDs prior to surgery, and younger age at the time of surgery served as predictors of postoperative long-term seizure outcome, and, as such, may improve clinical practice when selecting and counseling appropriate candidates for resective epilepsy surgery. The study results also underscored that epilepsy surgery should be considered early in the disease course of pediatric patients with FCD type II.

Prediction of the recurrence risk in patients with epilepsy after the withdrawal of antiepileptic drugs

Many seizure-free patients who consider withdrawing from antiepileptic drugs (AEDs) hope to discontinue treatment to avoid adverse effects. However, withdrawal has certain risks that are difficult to predict. In this study, we performed a literature review, summarized the causes of significant variability in the risk of postwithdrawal recurrent seizures, and reviewed study data on the age at onset, cause, types of seizures, epilepsy syndrome, magnetic resonance imaging (MRI) abnormalities, epilepsy surgery, and withdrawal outcomes of patients with epilepsy. Many factors are associated with recurrent seizures after AED withdrawal. For patients who are seizure-free after treatment, the role of an electroencephalogram (EEG) alone in ensuring safe withdrawal is limited. A series of prediction models for the postwithdrawal recurrence risk have incorporated various potentially important factors in a comprehensive analysis. We focused on the populations of studies investigating five risk prediction models and analyzed the predictive variables and recommended applications of each model, aiming to provide a reference for personalized withdrawal for patients with epilepsy in clinical practice.

Sociodemographic Factors in Pediatric Epilepsy Surgery

BACKGROUND

Despite documented efficacy of surgical treatment in carefully selected patients, surgery is delayed and/or underutilized in both adult and children with focal onset epilepsy. The reasons for surgical delay are often assumed or theorized, and studies have predominantly targeted the adult population. To focus on a more targeted pediatric population and to determine identifiable reasons for intervention, this study aimed to investigate time to epilepsy surgery among pediatric patients with medically intractable epilepsy associated with focal cortical dysplasia and to identify sociodemographic and clinical associations in time to epilepsy surgery.

METHODS

We reviewed 96 consecutive pediatric patients who underwent surgery for medically intractable epilepsy with a diagnosis of focal cortical dysplasia. Descriptive statistics, univariate and multivariate analyses were conducted to study the association of sociodemographic variables of patients with focal cortical dysplasia and time to epilepsy surgery and postoperative seizure control.

RESULTS

We identified that non-white patients on average had a longer duration of epilepsy before surgery and traveled shorter distances for care. Non-white patients were more likely to have government-funded insurance. Patients who traveled the shortest distance to the surgical center underwent epilepsy surgery at an older age.

CONCLUSIONS

Sociodemographic factors of travel distance, insurance, and race influenced time to epilepsy surgery for children with focal cortical dysplasia. Further research is warranted to target barriers in access to subspecialty care and develop ways to identify earlier the patients who may benefit from evaluation and deployment of surgical intervention.

Comparison of the relapse rates in seizure-free patients in whom antiepileptic therapy was discontinued and those in whom the therapy was continued: A meta-analysis

About 70% of patients with epilepsy can be seizure-free with an appropriate treatment. When the seizures are under control, discontinuation of the antiepileptic drugs (AEDs) can help avoid their side effects; however, it may increase the risk of relapse. Some studies have compared the relapse rates between patients in whom AEDs have been continued and those in whom AEDs have been discontinued. However, it is not clear whether AED discontinuation causes a higher seizure recurrence rate. This meta-analysis aimed mainly to determine whether the seizure recurrence rate was different between seizure-free patients in whom AEDs were continued and those in whom AEDs were discontinued. The I² value was used for assessing the heterogeneity; the Mantel-Haenszel test was used to calculate the odds ratios (ORs) with 95% confidence intervals (CIs). Seven cohort studies and randomized controlled trials (RCTs) met the inclusion criteria. The study quality evaluation was performed respectively using the Newcastle-Ottawa Scale and the Jadad scale. A total of 1253 patients were included. The relapse rate was higher in patients in whom AEDs were discontinued than in those in whom the AED treatment was continued. Furthermore, we also compared the epilepsy recurrence rates after AED discontinuation between seizure-free patients who were on monotherapy with different AEDs (carbamazepine, phenytoin, sodium valproate, and phenobarbitone/primidone). Four studies and 625 patients were included in this analysis. The epilepsy recurrence rates did not significantly differ between the patients on different AED treatment.