Treatment of Epilepsy : A Practical Guide for Neurosurgeons

Abstract

  Neurosurgeons comprise 20% of the members of the Japan Epilepsy Society and play a significant role in the diagnosis and treatment of adult epilepsy in Japan. We describe advances in the understanding and management of epilepsy in clinical practice.

  The potential role of genetic and autoimmune mechanisms as etiopathogenetic contributors to epilepsy has generated much interest among researchers. A recent genome-wide association study that included approximately 15,000 patients with epilepsy and approximately 30,000 controls identified 16 genome-wide significant loci and 21 candidate genes in these loci. The identified common genetic variants explain 32% and 9% of the liability to generalized and focal epilepsies, respectively.

  The discovery of an increasing number of neural autoantibodies in patients with epilepsy implicates autoimmunity as a likely mechanism underlying the etiology of this condition ; recent studies show that immunotherapy is more effective than antiepileptic medications to control seizures. Moreover, most patients do not develop chronic epilepsy after immunotherapy. A subset of patients with autoimmune epilepsy, particularly the type associated with leucine-rich glioma-inactivated 1 (LGI1) antibody encephalitis, present with drug-resistant seizures unaccompanied by major cognitive or behavioral symptoms, which are often misdiagnosed. Anti-LGI1 encephalitis is characterized by faciobrachial dystonic seizures.

  Large-scale real-world data have established the efficacy and safety of new antiepileptic drugs (AEDs). The registry of pregnant women who received antiepileptic monotherapy showed that the risk of major congenital malformations was significantly lower in children whose mothers received new AEDs than in children whose mothers received older AEDs. Notably, the new drugs showed similar effectiveness in seizure control during pregnancy.

  Less invasive approaches are increasingly being used in epilepsy surgery. Magnetic resonance-guided laser interstitial thermal therapy has emerged as a promising alternative to surgical treatment of mesial temporal lobe epilepsy. Responsive neurostimulation is used as adjunctive therapy for non-resectable focal epilepsies. Stereoelectroencephalography is gaining popularity for intracranial electroencephalography since the introduction of robot-assisted stereotactic electrode implantation. However, currently, the aforementioned less invasive modalities (except for the robotic system) are unavailable in Japan. The introduction of less invasive approaches potentially expands the surgical indications for epilepsy treatment.

  In summary, ongoing research is unraveling the diverse etiologies of epilepsy. Therefore, based on the underlying pathophysiology, a variety of treatment options are available to enable individualized therapy for epilepsy.