LAUSR

Restless legs syndrome (RLS) is characterized by an urge to move the legs, classically accompanied by uncomfortable sensations. Symptoms typically worsen during rest and at night. Pharmacotherapy includes levodopa/dopamine agonists, anticonvulsants (alpha-2-delta ligands), opioids, and iron supplementation. Nonpharmacologic approaches involve pneumatic compression, near-infrared spectroscopy, or transcranial magnetic stimulation. One patient who underwent spinal cord stimulation (SCS) for neuropathic pain experienced improvement of concomitant RLS. Analogously, spinal transcutaneous direct current stimulation and limb transcutaneous electrical nerve stimulation may improve RLS. Currently, SCS to specifically treat RLS has not yet been reported. We present an otherwise healthy 24-year-old student suffering nonfamilial RLS. Symptoms started at age 12 and gradually progressed. He reported a crawling leg sensation at rest, alleviated by mobilizing, maximum at night, but eventually present throughout the day. He slept only 4 to 5 hours nightly and had prolonged sleep latency. Besides repetitive voluntary leg movements, neurological examination was normal. Polysomnography performed elsewhere excluded sleep disordered breathing (apnea hypopnea index 2.1 without significant oxygen desaturation) and demonstrated periodic limb movement arousals (indices unavailable). Serum markers measuring iron status (total iron = 20 μmol/L [9-32], ferritin = 170 μg/L [22-275], transferrin saturation = 33% [20-50]) and thyroid and renal function were normal. He was on zolpidem 10 mg, clonazepam 0.25 mg, and medical marijuana with limited benefit. Levodopa/carbidopa, pramipexole, and ropirinole initially improved RLS but subsequently contributed to augmentation. Rotigotine, retigabine, gabapentin, pregabalin, loprazolam, zolpidem, melatonin, venlafaxine, morphine, oxycodone, codeine, nabilone, oral iron supplementation, cognitive behavioral therapy, and compression socks were ineffective. Ferric carboxymaltose was unavailable in Canada. He refused methadone. Transcutaneous electrical nerve stimulation only helped partially and was cumbersome. After a multidisciplinary review, institutional approval, and detailed consenting, a spinal epidural paddle electrode was implanted at T7-9 under general anesthesia (Fig. 1B). Following a 1-week inpatient trial period, confirming good leg coverage and symptom improvement, an internal pulse generator (IPG) was implanted and programmed (Fig. 1C). Subjectively, his legs were instantaneously less restless with SCS on, even in the absence of SCS-induced paresthesia, for example, with stimulation in certain positions or at lower amplitudes. Six months postoperatively, the International RLS Study Group rating scale and RLS 6-item questionnaire scores were reduced by 44% and 25%, respectively. This translated into a 33% improvement in RLS-Quality of Life questionnaire score (Fig. 1A). Subjectively and polysomnographically, sleep quality (no more periodic limb movement arousals) and duration (6-8 hours) improved, with some remaining sleep onset insomnia. Medication was gradually tapered to exclusively zolpidem 5 mg occasionally. This benefit is sustained at 33 months, with gradual worsening upon IPG depletion and instantaneous improvement after IPG replacement (Fig. 1A). SCS was considered on experimental and theoretical grounds. Theoretically, SCS-induced paresthesia may override uncomfortable ascending sensations, similar to one postulated mechanism in neuropathic pain. Indirect action via modulation of sensory cortices and/or cerebellum is also possible. SCS may substantially improve RLS severity and quality of life. Although this is a single case and SCS-induced paresthesia renders blinding difficult, symptom recurrence/improvement upon IPG depletion/replacement, respectively, is encouraging. However, a placebo response, common in RLS, cannot be excluded. Further study is warranted to define the role of SCS in medication-refractory RLS.