Abstracts

Rationale: Responsive neurostimulation (RNS System or RNS) is a programmable and responsive device indicated as a treatment option for patients with medically intractable epilepsy. In addition to the treatment provided by chronic responsive neurostimulation, RNS has the added benefit of providing long-term electrocorticography (ECoG) recording, which can help with diagnosis and inform treatment decisions. Although RNS stimulation is typically initiated about 4 weeks after surgical placement, there may be occasional therapeutic benefit to activating stimulation immediately or shortly after surgical placement in select cases. We reviewed three cases at our center in which ECoG was analyzed perioperatively following implantation, and stimulation initiated early, and the rationale and utility of doing so.

Methods: We performed a retrospective review of all RNS cases implanted at our center and identified cases where ECoG was used diagnostically in the acute inpatient setting during or immediately after implantation, and stimulation initiated early.

Results: Three cases were identified where RNS ECoG and stimulation were used in the acute inpatient setting following implantation. One patient was encephalopathic post-operatively and scalp continuous electroencephalogram (EEG) monitoring did not capture seizures. RNS was interrogated and ECoG revealed seizures missed on scalp EEG. RNS stimulation was enabled and encephalopathy improved. The second patient had RNS placed during active status epilepticus and ECoG was used diagnostically in tandem with scalp EEG to assess, stimulate and treat status epilepticus. The third patient had concern for status epilepticus with clustered seizures on post-operative day one and thus RNS was interrogated and stimulation enabled with subsequent clinical improvement. In all three cases, RNS was used as both a diagnostic and therapeutic tool in the inpatient perioperative setting.

Conclusions: Although RNS has been shown to be an effective long-term treatment for refractory epilepsy, RNS can also be used acutely in the inpatient setting to help with detection and treatment of seizures. Expedited programming may be beneficial for select epilepsy patients with perioperative course complicated by encephalopathy, seizure clustering, or status epilepticus. ECoG can be used as an adjunct with scalp EEG as a diagnostic tool, at times offering improved accuracy compared with scalp EEG. RNS also offers a non-medication therapeutic option in the acute setting. There may be clinical utility to reviewing ECoG shortly after implantation to assure adequate detection and potentially allow for revisions to be made during the same hospitalization if necessary. Further study is indicated to explore optimal timing of initiation of stimulation, and potential utility of early activation.

Funding: Please list any funding that was received in support of this abstract.: N/A.