Risk factors for preoperative seizures in intracranial meningiomas.

Background: About 25% of patients with intracranial meningioma display seizures at the time of initial presentation. Hence, identification of risk factors for preoperative seizures is crucial during perioperative care of meningioma patients.
Methods: Associations of preoperative seizures with clinical, radiological and histological variables were analyzed in 945 patients (689 females, 73% and 256 males, 27%; median age: 58 years) who underwent surgery for primary diagnosed intracranial meningioma.
Results: Preoperative seizures were found in 189 patients (20%). In univariate analyses, male gender (OR=1.91, 95% CI: 1.37-2.68; P<0.001), grade II/III histology (OR=2.24, 95% CI: 1.46-3.46; P<0.001), brain invasion (OR=2.59, 95% CI: 1.45-4.63; P=001), non-skull base tumor location (OR=3.07, 95% CI: 2.13-4.41; P<0.001), heterogeneous contrast-enhancement (OR=1.60, 95% CI: 1.04-2.46; P=0.031), intratumoral calcifications (OR=1.91, 95% CI: 1.17-3.10; P=0.009), an irregular shape (OR=2.07, 95% CI: 1.32-3.26; P=0.002) as well as tumor (OR=1.01 per ccm, 95% CI: 1.00-1.02; P=0.001) and edema volumes (OR=1.01 per ccm, 95% CI: 1.00-1.01; P<0.001) were correlated with seizures. Semiology was not related to any of the analyzed variables (P>0.05, each). No associations were found between seizures and histological subtype of 832 grade I meningiomas (P=0.391). In multivariate analyses, only non-skull base tumor location (OR=3.12, 95% CI: 1.74-5.59; P<0.001) and a rising peritumoral edema volume (OR=1.01 per ccm, 95% CI: 1.00-1.01; P<0.001) were identified as independent predictors for preoperative seizures.
Conclusions: Several mostly radiological variables were identified as risk factors for epilepsy. However, multivariate analyses confirmed only peritumoral edema and non-skull base tumor location as independent predictors for preoperative seizures. None of the variables predicts semiology.