Consensus Study Report on Pediatric Epilepsy Surgery

Background Introduction

The incidence of epilepsy varies significantly across different age groups. According to the International League Against Epilepsy (ILAE), the highest incidence rates of epilepsy are found among those under 5 years old and over 65 years old (>60 per 100,000 people), with children under 1 year old having a higher incidence rate (82.1–118 per 100,000 per year) compared to older children (46 per 100,000 per year). Based on a 30-year cohort study on antiepileptic drug (ASM) treatment, it was found that the first use of ASM can achieve seizure freedom in 50.5% of patients; the likelihood of seizure freedom with the second ASM is 11.6%, and the additional seizure-free rate with the third treatment is only 4.1%. Furthermore, a single-center randomized trial confirmed the superiority of epilepsy surgery for drug-resistant epilepsy (DRE) in children under 18.

Although researchers widely recognize the value of epilepsy surgery in treating DRE, significant treatment gaps persist, particularly in young children, due to various factors. Pediatric epilepsy surgery, especially in children under 6 years old, shows notable differences in preoperative evaluation and surgical techniques compared to older children and adults. Most prior studies have involved adult and pediatric cases, but these studies had limited sample sizes and poor homogeneity in populations and methods. Furthermore, previous research mainly focused on postoperative efficacy and prognosis, with less discussion on preoperative evaluation and specific surgical strategies/techniques. Additionally, with the rapid development of preoperative evaluation and surgical techniques, researchers have updated some previous concepts, processes, and conclusions.

To further standardize preoperative evaluation and surgical plans for pediatric epilepsy surgery, the China Association Against Epilepsy (CAAE) established an expert task force (TF) aimed at reaching consensus through extensive surveys and actively promoting the advancement of pediatric epilepsy research.

Source Introduction

This paper was published in the journal “Acta Epileptologica,” and the authors include Lixin Cai, Kai Zhang, Wenjing Zhou, Xiaoqiu Shao, Yuguang Guan, Tao Yu, Ye Wu, Shuhua Chen, Rui Zhao, Shuli Liang, Xun Wu, Guoming Luan, Yuwu Jiang, Jianguo Zhang, and Xiaoyan Liu. The publication date is 2023.

Research Methods

The research team applied a modified Delphi method, conducting two rounds of anonymous surveys among 75 experts from four subgroups: pediatric neurologists, epileptologists, pediatric epilepsy surgeons, and functional neurosurgeons. The survey content included participants, the 2010 ILAE definition of DRE, and assessments mainly involving curative epilepsy surgery. Neurostimulation therapies were excluded due to differences in treatment mechanisms.

Through two rounds of surveys, consensus was reached in most areas, including preoperative evaluation, surgical strategies and techniques, perioperative and long-term postoperative management, although there were some contentious opinions on certain items.

Research Details

Preoperative Evaluation

All children with DRE should be referred to epilepsy centers for comprehensive diagnostic and therapeutic evaluation. The purposes of preoperative evaluation include confirming the diagnosis and classification of epilepsy, determining the cause and surgical indications, localizing the epileptogenic zone, formulating the surgical plan, and assessing the risks and benefits of surgery.

Etiological Diagnosis

Unlike adult DRE, the etiology of pediatric DRE is more complex and diverse. According to the 2017 ILAE classification of epilepsy, structural, genetic, infectious, metabolic, immune, and unknown causes should undergo systematic reassessment during preoperative evaluation. Initially, clinicians should conduct thorough history taking, physical examinations, MRI, and necessary laboratory tests to exclude genetic, metabolic, degenerative diseases, autoimmune encephalitis, and diffuse brain injuries that are unsuitable for epilepsy surgery.

Neuroimaging

All children with DRE should undergo MRI using “Harmonized Neuroimaging of Epilepsy Protocol” (HARNESS)–MRI. For infants, high-resolution T2-weighted images are recommended to switch from the coronal to the axial plane to better identify cortical dysplasia. T2-FLAIR imaging is unnecessary for neonatal MRI. Given the myelination process in infants and toddlers continues until age 2, children with unexplained causes and/or unclear neuroimaging lesions should undergo MRI every 6-12 months until 36 months to identify potential brain structural abnormalities. Special MRI sequences are not recommended as routine checks.

Nuclear Medicine Examinations

18F-fluorodeoxyglucose PET is a routine check in the preoperative evaluation of pediatric epilepsy. Regular PET and MRI coregistration (post-processing) are recommended to enhance localization resolution. Due to ionizing radiation and the constraints on injection time, SPECT poses challenges for young children and therefore no consensus was reached.

Neurophysiological Examinations

Long-term video EEG (VEEG) monitoring is a routine method for preoperative evaluation. Regardless of age, VEEG monitoring for preoperative evaluation should meet the technical requirements of the CAAE “Clinical EEG Technology Guidelines.” Needle electrodes should not be used as sphenoidal electrodes in children, and the importance of surface electromyography in determining seizure types is emphasized. Typically, three to five habitual seizures should be recorded.

Surgical Indications

For children with drug-resistant epilepsy, surgical indications are not clearly defined, but consensus was reached on most issues involving epilepsy surgery. For children with DRE where MRI and PET fail to identify explicit epileptogenic zones and show bilateral extensive brain abnormalities, surgery is not indicated.

Results

The first-round questionnaire included 99 descriptive items and opinions on age, preoperative evaluation, surgical strategies, perioperative management, and long-term postoperative management. The second-round questionnaire designed 65 questions to more specifically describe specific issues or contentious questions from the first-round survey. The first-round questionnaire feedback rate was 98.8%, with a response rate for each question ranging from 68.7% to 85.9%. The second-round questionnaire feedback rate was 88.2%, with a response rate ranging from 55.4% to 83.1%.

Age Group Division

The age groups for pediatric epilepsy surgery were further refined to develop more precise and reasonable preoperative evaluations and surgical plans. Early infancy (0-3 months), school age ( years), and preschool age ( years) each have specific imaging characteristics and key points related to surgical strategies.

Preoperative Evaluation

Includes defining the cause of epilepsy classification, localizing epileptogenic foci, surgical planning, and assessing postoperative risks and benefits.

Surgical Strategies and Techniques

Different surgical strategies are formulated for different epileptogenic causes. Structural epilepsy lesions are mainly treated through resection or disconnection of the foci. For multiple lesions, staged surgery can be considered. Other specific pathologies like tuberous sclerosis, cortical microdysgenesis, and gray matter heterotopia require particular attention to the identification of epileptogenic foci during surgical treatment.

Postoperative Management

Includes long-term antiepileptic drug treatment and follow-up. Postoperatively, adjustments to antiepileptic drugs are needed, and long-term follow-up is required to observe epilepsy recurrence and surgical outcomes.

Conclusion

Pediatric epilepsy surgery significantly differs from that in older children and adults in terms of preoperative evaluation, surgical strategies and techniques, perioperative, and long-term postoperative management. Using the Delphi survey method, this study conducted two rounds of anonymous interviews with 75 experts from the four subgroups, eventually reaching widespread consensus on most issues. These consensuses will help improve the surgical treatment and overall management level of pediatric drug-resistant epilepsy and promote multidisciplinary collaboration. For some items where no consensus was reached, recommendations were proposed through in-depth discussions.