Rates and predictors of seizure freedom in resective epilepsy surgery: an update

Abstract

Epilepsy is a debilitating neurological disorder affecting approximately 1 % of the world’s population. Drug-resistant focal epilepsies are potentially surgically remediable. Although epilepsy surgery is dramatically underutilized among medically refractory patients, there is an expanding collection of evidence supporting its efficacy which may soon compel a paradigm shift. Of note is that a recent randomized controlled trial demonstrated that early resection leads to considerably better seizure outcomes than continued medical therapy in patients with pharmacoresistant temporal lobe epilepsy. In the present review, we provide a timely update of seizure freedom rates and predictors in resective epilepsy surgery, organized by the distinct pathological entities most commonly observed. Class I evidence, meta-analyses, and individual observational case series are considered, including the experiences of both our institution and others. Overall, resective epilepsy surgery leads to seizure freedom in approximately two thirds of patients with intractable temporal lobe epilepsy and about one half of individuals with focal neocortical epilepsy, although only the former observation is supported by class I evidence. Two common modifiable predictors of postoperative seizure freedom are early operative intervention and, in the case of a discrete lesion, gross total resection. Evidence-based practice guidelines recommend that epilepsy patients who continue to have seizures after trialing two or more medication regimens should be referred to a comprehensive epilepsy center for multidisciplinary evaluation, including surgical consideration.

Functional connectivity disturbances of the ascending reticular activating system in temporal lobe epilepsy

“…However, it is important to note that this is only a hypothesis, and while associations between ARAS connectivity and disease and neurocognitive parameters were observed in the present study, causation cannot be inferred. Progressive network dysfunction and neuropsychological impairments seen in focal epilepsy demonstr at e the critical importance of achieving seizure freedom in this disorder through medical or surgical intervention 36. In future studies, it will be important to determine whether definitive epilepsy treatment, including successful epilepsy surgery, is associated with reversal of connectivity reorganisation.…”

Loss of CLOCK Results in Dysfunction of Brain Circuits Underlying Focal Epilepsy

“…Most patients have focal epilepsy, and their seizures arise from discrete pathological regions of abnormal brain tissue. Surgical resection of the “focus,” where seizures originate, often ameliorates refractory, medication-resistant epilepsy (Englot and Chang, 2014). Despite its clinical importance, the molecular mechanisms defining epileptogenic tissue are poorly understood.…”

Towards Large-Scale, Human-Based, Mesoscopic Neurotechnologies

“…The rates of complete seizure control after surgery can be as high as 80%, and follow-up studies have documented the long-term success of surgical treatments (Englot and Chang, 2014; Englot et al, 2012; Jobst and Cascino, 2015). However, the outcome of epilepsy surgery critically depends upon whether the seizure source can be well localized.…”