Oedema as a prognostic factor for seizures in meningioma - a systematic review and meta-analysis

Meningiomas are benign intracranial tumours that commonly lead to seizures and oedema. An understanding of seizure risk factors is essential for the meningioma community. Many studies have differing conclusions on whether oedema is associated with seizure. Existing meta-analyses are limited by lack of focus on oedema. Our objective was to summarise all literature on oedema as a prognostic factor for seizures in meningioma patients. We searched OVID, Scopus, Pubmed, Web of Science, ClinicalTrials.gov and Google scholar up to April 2024 for reports with more than 10 human meningioma participants. Statistics were performed on R-Studio. Cochrane and Campbell guides for systematic reviews and meta-analysis were followed. Risk of bias was assessed with ROBINS-E. Our protocol was uploaded to INPLASY. We included 51 studies for meta-analysis and 21 for narrative review. Most studies were of surgically treated adults. Heterogeneity was low once outliers were removed. Preoperative oedema was associated with preoperative seizure (k = 28, n = 7,725, OR 3.5, 95% CI = 3.1-4.0, I2 = 0%, p < .001), early postoperative seizure (k = 9, n = 2,929, OR 1.5, CI = 1.1-1.9, I2 = 0%, p = .011) and late postoperative seizure (k = 9, n = 2,150, OR 1.9, CI = 1.5-2.2, I2 = 0%, p < .001). We performed an additional adjusted analysis for preoperative seizures which was also significant (k = 3, n = 2,241, OR 3.9, CI = 2.4-6.3, I2 = 0%, p = .007). There were few studies of post-radiosurgery oedema and seizure, and of postoperative oedema and seizure, with insignificant but positive associations. Preoperative oedema is a key factor for preoperative seizures. Oedema also increases risk of postoperative seizures. Further study in conservative, radiosurgery and paediatric populations, as well as study of oedema and seizure severity or subtype is warranted.