Surgical Approaches for Seizure Control in Low-Grade Gliomas Using ETT-SpTR

Overview

This study evaluates the efficacy of supratotal resection (SpTR) tailored by intraoperative electrocorticography (iECoG) and navigated transcranial magnetic stimulation (nTMS) in controlling seizures in patients with low-grade gliomas (LGG). The combined approach aims to improve seizure freedom by including epileptic foci in resection while preserving neurological function.

Background

Epileptic seizures are common in patients with low-grade gliomas and often persist after gross total resection, negatively impacting quality of life. Supratotal resection, which extends beyond tumor margins to include epileptic foci in the peritumoral cortex, may improve seizure outcomes but is limited by proximity to eloquent brain areas. Intraoperative electrocorticography helps localize epileptic foci, while navigated transcranial magnetic stimulation predicts functional cortical areas to avoid deficits, enabling a tailored SpTR approach.

Data Highlights

Patients underwent preoperative MRI with diffusion tensor imaging and nTMS mapping for motor, language, and calculation functions. Intraoperative iECoG was used to identify epileptiform activity along resection margins. Antiseizure medication with Levetiracetam was administered pre- and postoperatively. The surgical approach integrated neuronavigation to maintain safe distances from functional areas during extended resection.

Key Findings

• Epileptic foci in LGG are located in the peritumoral neocortex micro-infiltrated by tumor cells, often outside the gross tumor margin.
• Standard gross total resection frequently fails to remove epileptic foci, leading to persistent postoperative seizures.
• Intraoperative electrocorticography effectively identifies cortical areas with high epileptiform activity, guiding extension of resection beyond tumor boundaries.
• Navigated transcranial magnetic stimulation accurately maps functional cortical areas, validated by direct cortical stimulation, to avoid postoperative neurological deficits during extended resection.
• The combined ETT-SpTR approach allows tailored supratotal resection that includes epileptic foci while preserving function.
• Perioperative management with Levetiracetam and specific anesthetic protocols preserves iECoG signal quality for reliable intraoperative monitoring.

Clinical Implications

Incorporating iECoG and nTMS into surgical planning enables more precise identification and resection of epileptic foci in LGG patients, potentially increasing seizure freedom rates. This tailored supratotal resection balances oncological control with preservation of neurological function, improving quality of life in a young patient population with long survival. Careful anesthetic management is essential to maintain intraoperative electrophysiological monitoring fidelity.

Conclusion

The ETT-SpTR approach utilizing intraoperative electrocorticography and navigated transcranial magnetic stimulation represents a promising strategy to enhance seizure control in low-grade glioma surgery by extending resection to epileptic foci while safeguarding functional cortex.

References

1. Various Authors/Studies -- Surgical Approaches for Seizure Control in Low-Grade Gliomas