# Meningiomas-Related Epilepsy After Surgery

## TL;DR

This study finds that preoperative peritumoral edema predicts better seizure outcomes after meningioma surgery, helping guide when to stop antiseizure medications.

## Contribution

The novel finding is that preoperative peritumoral edema is a positive predictor for discontinuing antiseizure medications after meningioma surgery.

## Key findings

- Preoperative peritumoral edema is associated with improved postoperative seizure outcomes.
- Surgical resection significantly reduces seizure rates in patients with preoperative peritumoral edema.
- Peritumoral edema is a key factor in deciding when to stop antiseizure medications after surgery.

## Abstract

There is limited evidence regarding the epileptogenesis and management of meningioma-related epilepsy (MRE). Our study aims to identify risk factors for postoperative MRE to guide clinicians in discontinuing antiseizure medications (ASMs) after treating supratentorial meningiomas. Our results show that preoperative peritumoral edema (PE) is the only factor that can predict an excellent seizure outcome following meningioma resection, likely because surgery leads to its resolution. Furthermore, PE is also associated with a higher risk of preoperative epilepsy, highlighting its potential key role in the epileptogenesis of MRE. Therefore, based on our clinical experience, preoperative PE may be a positive factor in the decision-making process for discontinuing ASMs after surgery. To our knowledge, this finding has not been previously reported in the literature.

Background: Meningioma-related epilepsy (MRE) is observed in approximately 30% of patients. Although studies focus on identifying risk factors related to pre- and postoperative MRE, there is no clear evidence regarding the timing for discontinuing antiseizure medications (ASMs) after surgical resection. Methods: We retrospectively collected data from a series of naïve supratentorial meningiomas treated with surgical resection. Preoperative MRI was used to calculate the meningioma and peritumoral edema (PE) volumes through a voxel-based system. We analyzed the frequency of pre- and postoperative epilepsy in the group of meningiomas with and without perilesional edema (with PE > 1 cm3 as the cut-off). Results: From a clinical series of 507 patients, we included 128 who underwent surgical resection in our center between January 2020 and December 2022, with a mean follow-up of 30.1 ± 19.8 months. Surgical treatment had a curative effect on MRE (41.4% preoperative vs. 19.5% postoperative; p = 0.0001). We observed a statistically significant reduction in the seizure rate in cases with preoperative PE (45.3% preoperative vs. 18.9% postoperative; p = 0.0002) and a non-statistically significant reduction in cases without PE (32.5% preoperative vs. 21.4% postoperative; p = 0.24). We observed ASM continuation in 37.8% of Engel IA patients. Conclusions: PE increases the likelihood of MRE resolution with surgery. Our results show that surgical resection directly impacts MRE and ASM discontinuation in the presence of preoperative PE. The PE is a reassuring factor in decision-making regarding the timing of ASM discontinuation after surgery.