Abstracts

Rationale: Seizures in patients with tuberous sclerosis complex (TSC) are often challenging to control, with over 37% of patients having focal, medically refractory seizures (Vignoli et al., Epilepsia 2013). Patients with TSC and intractable epilepsy are referred for surgical management of their seizures, but some are not candidates for resective surgery due to multiple epileptogenic zones (EZ) and/or EZ that overlap with eloquent cortex. Responsive neurostimulation (RNS) offers an alternative, adjunctive therapy for patients who are not candidates for resective surgery or in whom resective surgery is not curative. The literature reporting results on the pivotal trial and longer-term efficacy for responsive neurostimulation describe a patient population with medically intractable epilepsy and show that patients with lesional epilepsy may have a better response rate (Jobst et al., Epilepsia 2017), but there are limited reports describing the efficacy of this treatment specifically in patients with TSC. Methods: A 35-year-old right-handed man with a history of tuberous sclerosis complex and prior partial right frontal resection with continued intractable seizures underwent repeat evaluation for surgical candidacy including invasive video EEG monitoring. After his resective surgery at the age of 16, he continued to have approximately 4 seizures per day which were refractory to standard medical therapy. His seizures were characterized by fencer posturing with left arm extension and vocalizations with occasional lip smacking and turning to the right that arose from sleep. Initial evaluation showed that the seizures originated from an area of cortical dysplasia surrounding the prior resection cavity in the right anterior and mesial frontal lobe. Extraoperative electrocorticography demonstrated epileptogenic zones that overlapped with motor cortex. He was not a resective surgical candidate due to the onset occurring in eloquent cortex, but underwent successful implantation of an RNS device with two four-contact subdural strips placed in the parietal lobe and had subsequent outpatient programming of the device. Results: At 8 months post-implant, the patient has had approximately 50% seizure reduction from 3-4 seizures daily to 1-2 seizures daily, consistent with RNS responses reported in lesional epilepsy (Heck et al, 2014, Jobst et al, 2017). In addition, the patient has also reported improved cognition, especially in the area of language, and quality of life postoperatively. Conclusions: In this case, a patient with tuberous sclerosis complex (TSC) benefited from RNS System placement with a decrease in seizure frequency and an improved quality of life. Based on this case, if an epileptogenic zone cannot be feasibly resected due to overlap of the tuber and eloquent cortex or if there is additional risk from resection, responsive neurostimulation may offer alternative or adjunctive therapy that is safe and effective in treatment of patients with TSC. Funding: No funding