[Antiepileptic prophylaxis for elective neurosurgery]

Abstract

In tumoral surgery, the risk factors for perioperative epilepsy can be roughly grouped into two categories: those related to the preoperative patient's conditions (type and location of the tumors, their impact on the surrounding brain…) and those specifically related to surgery (cerebral edema, parenchymal hematoma, surgical approach, complete or incomplete resection...). The first category is supposed to be responsible for preoperative and late postoperative epilepsy, while the second would be more related to the risk of epilepsy in the first postoperative week (or may be even in the first 48hours). It is well accepted (but not always respected) by the neuro-oncologists that there is no indication for preventive antiepileptic drugs (AED) in a patient with a brain tumor that has never presented seizure. However, every seizure crisis must be treated medically. Neurosurgical procedure (which is also a key factor for controlling epilepsy when it occurs. The AED should then be maintained as appropriate. In the absence of preoperative treatment, it has never been shown that prophylactic AED significantly decreases the incidence of postoperative seizures, early or late. Yet, the opposite has not been shown neither, and many groups use AED despite the risk of side effects and an uncertain risk-benefit ratio. Currently, postoperative epilepsy is much less frequent than it was 20 or 30years ago, and the risk of AED side effects also decreases with the latest generation of molecules (such as levetiracetam). So, AED risks and benefits tend to diminish in parallel, but their relationship is still to be assessed. In practice, a modern attitude would restrict prophylactic AED use to the higher risk patients (preoperative epilepsy, temporal astrocytoma, the extent of edema and mass effect...). A drug of last generation should be used, starting one week before surgery. The duration of the treatment should be limited to one week postoperatively in the absence of seizure.