Abstracts

Rationale: Meningiomas are a common form of brain tumor, the presence of which is often associated with seizures. Following incomplete surgical resection of epileptogenic meningiomas, or consequent to damage to surrounding cortex produced by the meningioma or by its resection, the epilepsy related to these neoplasms, persists. In this investigation, we describe the risk factors, natural history, surgical management, and outcomes following surgery for recurrent or residual epileptogenic meningiomas. Methods: Through retrospective chart reviews, we identified all patients with persistent epilepsy following incomplete resection or recurrent cases of meningiomas over a 14 year interval. Procedures involving surgical removal of residual meningiomas via craniotomy and/or through adjuvant stereotactic radiosurgery, were reviewed. Data regarding patient demographics, pre-operative seizure presentation, pre-operative anti-epileptic drug use, initial resection surgery conditions and outcomes, location and histological subtype of meningiomas, use of postoperative stereotactic radiosurgery, post-resection epilepsy outcomes, subsequent meningioma re-resection surgery conditions and outcomes, post-operative anti-epileptic drug use, and resulting post-operative follow-up outcomes of ILAE and Engel scores over a range of follow-up dates were collected. Results: Eight patients (5 Females, 3 Males) with persistent epilepsy were identified following subtotal resection of WHO Grade I (75%), WHO Grade II (12.5%), and WHO Grade III (12.5%) meningiomas. Six cases of patients with persistent epilepsy following subtotal resection of WHO Grade I meningiomas were identified, with parafalcine (33%), perirolandic (33%), temporal (17%), and frontal (17%) locations. In four patients, subsequent gross total resection of the remnant WHO Grade I meningiomas and underlying areas of epileptogenic gliosis yielded marked post-operative improvement in patients’ epilepsy outcomes, with postoperative ILAE and Engel scores ranging from Ia to IIIa and 1 to 4, respectively. In two patients with residual WHO Grade I meningiomas, post-operative use of stereotactic radiosurgery was successful in reducing epilepsy complications following initial subtotal resection. In one case of an atypical, WHO Grade II parafalcine meningioma, recurrence was noted following initial gross total resection, causing persistent post-operative epilepsy. Following gross total resection of the recurrent meningioma, post-operative resolution of epilepsy was noted, with ILAE and Engel scores of Ia and 1, respectively. In one case of an anaplastic, WHO Grade III intraventricular meningioma, multiple series of recurrence were noted as the tumor progressed from WHO Grade I to III. Following the third gross total resection of the anaplastic meningioma aided by adjuvant stereotactic radiosurgery, epilepsy resolution was obtained, with ILAE and Engel scores of Ia and 1, respectively. Conclusions: In these cases of follow-up resection and/or radiotherapy of incompletely resected meningiomas in patients with refractory epilepsy, post-operative epilepsy outcomes were markedly improved, highlighting the importance of complete resection of meningiomas in patients undergoing epilepsy surgery. Funding: No funding