Insular/perisylvian epilepsy: Open resection versus stereotactic ablation (MR-guided laser ablation/radiofrequency thermocoagulation) versus responsive neurostimulation

The diagnosis and surgical treatment of insular epilepsy (IE) has increased exponentially over the last 20 years. While there is a growing body of literature reporting excellent seizure freedom rates, widespread adoption of IE surgery has been hampered by concerns of postoperative neurological morbidity-particularly motor, language and cognitive impairments. Minimally invasive alternatives, such as MR-guided laser thermal ablation and radiofrequency thermo-coagulation, have been increasingly used to treat IE—offering surgical alternatives with minimally invasive benefits and lower permanent morbidity, albeit at the cost of lower seizure freedom. Since the initial Responsive neurostimulation (RNS) pivotal trial, several groups have applied RNS for select cases of IE deemed poor resective surgical candidates, providing a surgical option of seizure reduction without the risk of neurological impairment. This chapter provides a review of the surgical strategies available for IE and aims to review (1) the advantages, disadvantages and indications for each technique; (2) the efficacy and morbidity profile associated with each approach; and (3) provide an evidence-based roadmap for clinicians.