Subperception dorsal root ganglion stimulation versus sham stimulation in established responders: a randomized, double-blind crossover clinical trial.

Abstract

subperception (paresthesia-free) dorsal root ganglion (DRG) stimulation is increasingly used for focal neuropathic pain, but sham-controlled evidence remains limited. We conducted a randomized, double-blind, sham-controlled crossover trial with enriched enrollment design in established DRG-stimulation responders. In this single-center trial, adults with chronic peripheral neuropathic or nociplastic pain with implanted DRG system and sustained response (≥50% pain reduction for ≥3 months on stable stimulation settings and medication) were randomized 1:1 to active→sham or sham→active stimulation. Participants completed two 5-day treatment periods separated by a 24-hour washout with stimulation off. Active stimulation was delivered at 90% of the perception threshold, and sham was stimulation off. The primary outcome was median pain intensity on a 0-10 Numeric Rating Scale (NRS). Secondary outcomes included patient satisfaction and Patient Global Impression of Change (PGIC) domains. Analyses used Wilcoxon signed-rank tests with Hodges-Lehmann estimates. In 20 randomized patients, pain intensity was lower during active than sham stimulation (median NRS 3.0 (IQR 2.0-4.0) vs 6.0 (IQR 4.0-7.0); Hodges-Lehmann median difference, -2.5; 95% CI -3.0 to -2.0; p<0.001). Patient satisfaction and all PGIC domains favored active stimulation. Two participants terminated one treatment period early per prespecified criteria; available data were retained. No serious or device-related adverse events were reported. In established DRG responders, subperception DRG stimulation produced clinically meaningful pain reduction and improved patient-reported outcomes compared with sham. These findings support efficacy during the maintenance phase of treatment, but their generalizability to unselected chronic pain populations or earlier treatment phases is limited. NCT07170722.