503: Single vs Double Ultrasound-Guided Hydrodissection in Carpal Tunnel Syndrome: A Randomised Trial

Topic: Clinical Science
Subtopic: Pain category (ICD-11), Chronic neuropathic pain, Treatment/management

Background and Aims: Ultrasound-guided hydrodissection (UGHD) has emerged as a minimally invasive treatment in carpal tunnel syndrome (CTS), but the optimal frequency of injection remains uncertain. This study compares the efficacy of single versus double injection hydrodissection of median nerve using 5% dextrose, in patients with CTS.

Methods: In this randomized controlled trial, 20 patients with mild to moderate CTS were allocated into two groups: Group A received a single UGHD with 10 mL of 5% dextrose, while Group B received the same injection at baseline and again at 4 weeks. Outcomes were assessed at baseline, 4, and 12 weeks. The primary outcome was pain intensity measured by Numerical Rating Scale (NRS). Secondary outcomes included Boston Carpal Tunnel Questionnaire Symptom Severity Scale (BCTQ-SSS), median nerve cross-sectional area (CSA) on ultrasound, and any adverse events.

Results: Both groups showed improvement over time in pain and symptom severity. However, the single-injection group demonstrated significantly greater pain reduction at 12 weeks compared with the double-injection group. Mean NRS at 12 weeks was 1.2 ± 1.03 in Group A versus 3.3 ± 2.00 in Group B (mean difference -2.1; p=0.011). Change-score analysis also showed greater improvement in Group A (-4.8 ± 1.55) than Group B (-2.4 ± 2.46; p=0.0195). No significant between-group differences were observed at 4 weeks for NRS, or at either follow-up for BCTQ-SSS and CSA. Within-group analyses showed significant improvement in most outcomes, particularly in the single-injection group. No major adverse events were reported.

Conclusions: In this interim analysis, both single and double injection UGHD were associated with clinical improvement in CTS. However, single injection produced superior pain relief at 12 weeks, while repeated injection offered no additional functional or sonographic benefit. Larger studies are needed to confirm these findings.

References: 1. Padua L, Cuccagna C, Giovannini S, et al. Carpal tunnel syndrome: updated evidence
and new questions. Lancet Neurol. 2023;22:255-67.
2. Evers S, Thoreson AR, Smith J, Zhao C, Geske JR, Amadio PC. Ultrasound-guided
hydrodissection decreases gliding resistance of the median nerve within the carpal
tunnel. Muscle Nerve. 2018 Jan;57(1):25-32.
3. Wu YT, Chen SR, Li TY et al. Nerve hydrodissection for carpal tunnel syndrome: a
prospective, randomized, double-blind, controlled trial. Muscle Nerve. 2019;59(2),
174–180.
4. Malahias MA, Johnson EO, Nikolaou VS, Kaseta MK, Babis GC. Hydrodissection of
the median nerve for the treatment of carpal tunnel syndrome: A cadaveric study. J
Hand Surg Eur Vol. 2021;46(5):542–8.
5. Smith J, Wisniewski SJ, Finnoff JT, Payne JM. Sonographically guided carpal tunnel
injections: the ulnar approach. J Ultrasound Med. 2008;27:1485-90.
6. Lee JY, Park Y, Park KD, Lee JK, Lim OK. Effectiveness of ultrasound-guided carpal
tunnel injection using in-plane ulnar approach: a prospective, randomized, single-
blinded study. Medicine (Baltimore). 2014;93:e350.
7. Wu YT, Ho TY, Chou YC, Ke MJ, Li TY, Tsai CK, Chen LC. Six-month efficacy of
perineural dextrose for carpal tunnel syndrome: a prospective, randomized, double-
blind, controlled trial. Mayo Clin Proc. 2017;92:1179-89.
8. Wu YT, Chen SR, Li TY, Ho TY, Shen YP, Tsai CK, Chen LC. Nerve hydrodissection
for carpal tunnel syndrome: a prospective, randomized, double-blind, controlled trial.
Muscle Nerve. 2019;59:174-80.
9. Lin MT, Lin CW, Chang KV, Wu WT, Özçakar L. Volume matters in ultrasound-
guided perineural dextrose injection for carpal tunnel syndrome: a randomized,
double-blinded, three-arm trial. Arch Phys Med Rehabil. 2020;101:2077-84.
10. Chen SR, Ho TY, Shen YP, Li TY, Su YC, Lam KHS, Chen LC, Wu YT. Comparison
of short- and long-axis nerve hydrodissection for carpal tunnel syndrome: a
prospective randomized, single-blind trial. Int J Med Sci. 2021;18:3488-97.
11. Eyvaz N, Adar S, Akçin AI, Dündar Ü, Toktaş H, Eroğlu S. Comparison of
ultrasound-guided hydrodissection with various volumes of 5% dextrose for carpal
tunnel syndrome: a prospective randomized controlled double-blind trial. Am J Phys
Med Rehabil. 2025;104:596-604.

12. Panwar A, Roy U, Srivastava AK, Surange PN, Gupta P. Enhancing nerve function
and reviving the unrecordable: a comprehensive analysis of the effects of a dual
hydrodissection protocol on clinical and nerve conduction parameters in mild-
moderate and severe carpal tunnel syndrome. Cureus. 2024;16:e75681.
13. Mathieu T, Lemmens E, Stassijns G. A safe and easy-to-use ultrasound-guided
hydrodissection technique for the carpal tunnel syndrome: a minimally invasive
approach. J Ultrasound. 2022;25:173-8.
14. Guo K, McCool L, Wang H, Guo D, Guo D. The modified ultrasound-guided distal-
to-proximal carpal tunnel injection with median nerve hydrodissection: a retrospective
safety review of 827 procedures. Hand (N Y). 2021;16:407-9.
15. Sergeant AC, Badr S, Saab M, Demondion X, Cotten A, Jacques T. Carpal tunnel
ultrasound: is the safe zone on the ulnar side of the median nerve really avascular?
Eur Radiol. 2020;30:887-94.

Presenting Author: Dr Rajendra Kumar Sahoo
Submitting Author: Rajendra Kumar Sahoo

Senior Author: Dr Rajendra Kumar Sahoo

IASP 2026 Global Year theme of Neuropathic Pain: Yes

• Dr Anjali Kumari - Kalinga Institute of Medical Sciences