Identifying Early Responders to Dry Needling for Lower-Limb Spasticity in Multiple Sclerosis: A Secondary Responder Analysis of a Pilot Randomized Controlled Trial

<b>Background/Objectives:</b> Response heterogeneity limits the implementation of dry needling for spasticity in multiple sclerosis (MS). This secondary analysis aimed to identify early responders and explore predictors of response. <b>Methods:</b> We conducted a responder analysis of a pilot randomized, double-blind, sham-controlled trial (NCT05956119) including 18 ambulatory MS patients with spasticity, randomized to a single session of dry needling (<i>n</i> = 9) or sham (<i>n</i> = 9). Sensitive responder criteria were defined as improvement ≥ 2.0 s in Timed Up-and-Go, ≥5 points in MSQOL-54 physical component, or ≥10% in 25-Foot Walk Test at 4 weeks. <b>Results:</b> Using these criteria, 33.3% (3/9) of dry needling recipients were classified as responders versus 0% (0/9) in the sham group (<i>p</i> = 0.214). Responders were more frequently observed among participants with relapsing-remitting MS (100% vs. 40%, <i>p</i> = 0.090) and lower baseline disability (Expanded Disability Status Scale 3.4 vs. 4.4). A positive association was observed between baseline pyramidal subscore and physical quality-of-life change, although this did not reach statistical significance (r = 0.52, <i>p</i> = 0.150) in the active group. <b>Conclusions:</b> Approximately one-third of participants met predefined responder criteria following dry needling; however, these findings should be interpreted as preliminary signals derived from an exploratory, underpowered pilot analysis. These results are hypothesis-generating and require confirmation in adequately powered trials.