Hydrodissection With or Without Corticosteroid Versus Corticosteroid-Only Injection for Carpal Tunnel Syndrome: Double-Blind Randomized Controlled Trial.

Introduction/aims: Hydrodissection is an emerging technique in the management of carpal tunnel syndrome. We aimed to compare the efficacy of hydrodissection with or without corticosteroid versus intra-carpal corticosteroid injection for treating carpal tunnel syndrome.

Methods: In total, 66 wrists with mild to moderate carpal tunnel syndrome were allocated to three study arms. Under ultrasound guidance, patients received a single injection consisting of 1 mL (40 mg) triamcinolone acetonide, 1 mL lidocaine, and 3 mL of saline, or 1 mL lidocaine, and 4 mL saline. Another group received 1 mL intra-carpal triamcinolone acetonide (40 mg) without ultrasound guidance. All participants were followed for 3 months post-injection. The primary outcome was the median nerve cross-sectional area. Secondary outcomes were symptom severity, functional status, electrodiagnostic test results, hang grip, and pain.

Results: Analyses showed a significant reduction in symptom severity, improvement in function, decrease in median cross-sectional area, and improvement in electrodiagnostic evaluations for all the interventions 3 months after the injections (all p < 0.05). However, there was no significant improvement in muscle strength with any of the interventions. Sensory distal latency decreased (p ≤ 0.004), and sensory nerve conduction velocity increased in all groups (p ≤ 0.001). For motor nerve evaluations, distal latency decreased significantly with the three interventions (p ≤ 0.003), while nerve conduction velocity in the forearm segment increased in the steroid-only group (p < 0.011). Group comparisons did not reveal any significant differences.

Discussion: All interventions were effective in improving symptom severity, function, and electrodiagnostic and ultrasound measures, with no significant differences observed between the treatments.

Trial registration: The trial was registered prospectively at the Iranian Registry of Clinical Trials website http://www.irct.ir/, a WHO Primary Register set up with the registration number IRCT20210613051566N1.