Efficacy of US-guided Hydrodissection for Carpal Tunnel Syndrome: A Prospective Randomized Controlled Trial

Background US-guided hydrodissection is a minimally invasive treatment for nerve entrapment syndromes. However, its independent therapeutic efficacy remains unproven because most studies combine hydrodissection with corticosteroids or dextrose. Purpose To evaluate and compare the clinical and sonographic outcomes and complication rates of three US-guided hydrodissection techniques for the treatment of carpal tunnel syndrome (CTS) and to assess the relative efficacy of hydrodissection. Materials and Methods Adults with refractory CTS were included in this prospective randomized controlled trial (May 2019 to November 2020). Baseline assessment included the Boston Carpal Tunnel Questionnaire (BCTQ), Visual Analog Scale (VAS), and US measurement of median nerve cross-sectional area (CSA). Participants were randomized into three single-blinded groups: group 1, US-guided hydrodissection with normal saline (NS); group 2, perineural corticosteroid injection; and group 3, US-guided hydrodissection with NS plus corticosteroid. For hydrodissection, injectate was administered around the median nerve until complete nerve separation was achieved. Follow-up was performed at 4, 12, and 24 weeks. A linear mixed-effects model was used to evaluate within-group and between-group changes over time. Results Thirty-nine participants (mean age, 42.22 years ± 10.46 [SD]; 20 male; 63 wrists) were included. Persistent improvement in BCTQ and VAS scores was observed in groups 1 and 3. At 24 weeks, minimal clinically important difference for BCTQ Symptom Severity Scale was achieved in 85.7% and 90.5% of wrists in groups 1 and 3, respectively, with no significant intergroup difference (P = .979). Although group 2 demonstrated early clinical improvement, symptoms recurred and outcomes at 24 weeks were not significantly different from baseline. Percentage reduction in median nerve CSA was greater in groups 1 and 3 than in group 2 at 12 weeks (43% and 46%, respectively, vs 11%; P = .0001). No major complications were observed. Conclusion US-guided hydrodissection with NS alone resulted in sustained clinical and morphologic improvement in CTS, and the addition of corticosteroid provided no additional benefit. Clinical trial registration no. CTRI/2018/12/016604 © RSNA, 2026.