Predicting outcome of epilepsy after meningioma resection

Risk of seizures before and after neurosurgical treatment of intracranial meningiomas

OBJECTIVE

To identify variables associated with the development of pre- and postoperative seizures in patients who underwent surgical resection of intracranial meningiomas, in a patient cohort not routinely treated prophylactically with antiepileptic drugs (AED).

PATIENTS AND METHODS

Retrospective cohort study of 295 patients that underwent resection of a supratentorial meningioma at Odense University Hospital in between 2007-2015. Multivariate logistic regression was used to identify variables significantly correlating with pre- and postoperative seizures. Retrospective chart review was used to identify the rates of seizure incidence in patients, and the effect of AED on them.

RESULTS

The presence of peritumoral edema (OR:18.00, 7.44-43.58) was identified as predictor of preoperative seizure, while headache (OR:0.43, 0.22-0.84) and neurological deficit (OR:0.18, 0.09-0.39) were associated with a reduced incidence of preoperative seizures. The rates of postoperative seizure were increased in meningiomas in the left side (OR:1.91, 1.11-3.29), and reduced for tumor location in the convexity/parasagittal/falx (OR:0.72, 0.59-0.88) as well as in the absence of postoperative complications (OR:0.19, 0.10-0.36). 24.4% of the patients experienced seizures preoperatively, and a complete seizure freedom was achieved in 63.9% of them. 75.6% of the patients did not experience seizures preoperatively, but 15.2% of them then developed seizures postoperatively. A total of 20.3% of the patients experienced seizures after surgery. Time to first seizure in patients that did not experience seizures preoperatively but developed seizures after surgery, was one week (47%). However, first time postoperative seizures were also observed within one month postoperative (21%) and three months after surgery (32%). AED had a treatment success rate of 98.2% in preoperative seizures, and 98.0% in postoperative seizures.

CONCLUSION

Seizures after supratentorial meningioma surgery is common also in patients with no seizures preoperatively and mainly occurs within the first three postoperative months. AED are effective in controlling seizures.

The role of prophylactic antiepileptic drugs for seizure prophylaxis in meningioma surgery: A systematic review

Meningiomas are the commonest type of primary brain tumours. Whilst most patients are seizure-free prior to surgery, antiepileptic drugs are frequently administered to reduce the risk of developing post-operative seizures. However, evidence to support their efficacy in providing this outcome is sparse. To this end, we performed a systematic review to assess the impact of prophylactic antiepileptic drugs on post-operative epilepsy rates in seizure-naïve patients undergoing craniotomy for resection of meningiomas. The literature search was performed using PubMed for studies published between January 1990 and November 2016. The total number of patients in each study was extracted and divided into cohorts according to administration of prophylactic antiepileptic drugs. Clinical characteristics, study type and post-operative epilepsy rates were recorded. A total of 11 studies involving 1143 patients met the selection criteria. There was no statistically significant difference in the number of patients who developed post-operative epilepsy in the cohort that received prophylactic antiepileptic drugs (20 of 766; 2.6%) and the cohort that did not (10 of 377; 2.7%) (Chi-square test; P=0.96). A detailed meta-analysis could not be performed due to the insufficiency in data reported. Based on the results of this systematic review, the routine use of antiepileptic drugs for seizure prophylaxis in seizure-naïve patients undergoing meningioma resection could not be substantiated. However, limitations of a systematic review should be considered on interpretation. High quality prospective randomised controlled trials are required to definitively answer this important clinical question.

Epilepsy-related brain tumors

Seizures are among the most common presentations of brain tumors. Several tumor types can cause seizures in varying rates; neuroglial tumors and the gliomas are the most common ones. Brain tumors are the second most common cause of focal intractable epilepsy in epilepsy surgery series, with the highest frequency being dysembryoplastic neuroepithelial tumors and gangliogliomas. Seizure management is an important part of the treatment of patients with brain tumors. This review discusses clinical features and management of seizures in patients with brain tumors, including, neuroglial tumors, gliomas, meningioma and metastases; with the help of recent literature data. Tumor-related seizures are focal seizures with or without secondary generalization. Seizures may occur either as initial symptom or during the course of the disease. Brain tumors related epilepsy tends to be resistant to antiepileptic drugs and treatment of tumor is main step also for the seizure treatment. Early surgery and extent of the tumor removal are important factors for achieving seizure freedom particularly in neuroglial tumors and low grade gliomas. During selection of the appropriate antiepileptic drug, the general approach to partial epilepsies can be followed. There are several factors influencing epileptogenesis in brain tumor-related epilepsy which also explains clinical heterogeneity of epilepsy among tumor types. Identification of molecular markers may guide future therapeutic approaches and further studies are needed to prove antitumor effects of different antiepileptic drugs.