Adaptive spinal cord stimulation improves restless legs syndrome: Case report, literature review, and mechanistic hypothesis

Abstract

Introduction: Restless legs syndrome (RLS) affects up to 30 million people in the United States alone. Medical therapies often fail to provide durable relief, and emerging work suggests a role for spinal cord stimulation (SCS) in treatment-refractory cases. We present sustained improvement in RLS symptoms with adaptive SCS, summarize prior reports from the literature, and outline a pathophysiological basis for dorsal column stimulation in RLS.

Methods: A SCS device for chronic neuropathic pain was implanted in a patient with co-morbid RLS. International RLS and modified RLS-6 scores were obtained preoperatively, during SCS trialing, and with chronic stimulation. A PRISMA review was performed to identify prior literature describing SCS effects on RLS symptoms.

Results: We trialed adaptive SCS in a 73-year-old female with chronic pain and co-morbid RLS. Her International RLS Score decreased from 35/40 (very severe) to 13/40 (moderate) during trial stimulation with sustained improvement at 3- and >12-months follow-up. Device interrogation revealed circadian changes in the current required to maintain the target ECAP amplitude. Literature search identified 11 publications and proceedings describing open loop SCS for RLS in 18 patients. Including this case, all but 2 (89 %) demonstrated a clinically significant decrease in IRLS scores (>3 points).

Discussion: To our knowledge, this is the first report of adaptive SCS targeting evoked spinal cord electrophysiology improving RLS symptoms. We hypothesize that SCS disrupts RLS urge via interactions with hyperexcitable proprioceptive circuits in the dorsal column. Prospective studies are needed to better understand whether and/or how SCS impacts treatment-refractory, primary RLS.

Keywords: Closed-loop stimulation; Electrical stimulation; Evoked compound action potential; Neuromodulation; Periodic limb movements; Restless legs syndrome; Sleep disorder.