The Volume Effect of Nerve Hydrodissection for Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is the most common peripheral entrapment neuropathy with involving compression of the median nerve in the carpal tunnel. Although many conservative managements of CTS, the effectiveness of these methods is insignificant or only persist for a short duration. The technique of nerve hydrodissection is now commonly used for peeling the nerve from surrounding soft tissue, which may help allow the impulse to pass, and rescue the nerve with ischemic damage. However, the exact effect and interval of hydrodissection are unknown because of the lack of well-designed studies Hence, investigators design a randomized, double- blind, controlled trail to assess the therapeutic effect of ultrasound-guided nerve hydrodissection in patients with CTS.

After obtaining written informed consent, patients clinically diagnosed with mild-to-moderate CTS were inclused and randomized into three groups. Group A, patients received one-session of ultrasoung-guided nerve hydrodissection with 10cc normal saline; Group B, patients received one-session of ultrasoung-guided nerve hydrodissection with 5cc normal saline; The injection syringe was covered to obscure the nature of its contents and patients were asked to turn their head away so that they would not see the procedure. As a result, patients were blinded to the treatment condition. The primary outcome is Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) and secondary outcomes include visual analog scale (VAS), cross-sectional area (CSA) of the median nerve, sensory nerve conduction velocity of the median nerve, and global assessment of treatment. The evaluations were performed pretreatment as well as on the 2nd week, 1st, 3rd and 6th month after injecton.

Ultrasound-guided nerve hydrodissection with 10cc normal saline between carpal tunnel and median nerve.

Ultrasound-guided nerve hydrodissection with 5cc normal saline between carpal tunnel and median nerve.

Change from baseline of severity of symptoms and functional status on 2nd week, 1st, 3rd and 6th month after injection

Using the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) to measure the severity of symptoms and functional status before treatment and multiple time frame after treatment. BCTQ includes two subscale (11 questions in symptom severity and 8 questions in functional status). The scores ranged from 0 to 5 points in each question, in which zero score refered to as mildest and no difficulty in activity; five scores mean most worst severity and dysfunction.

Using the Visual analog scale (VAS) to measure the pain scale before treatment and multiple time frame after treatment. The VAS score range from 10 (tremendously harsh pain) to 0 points (no pain)

Change from baseline of cross-sectional area of the median nerve on 2nd week, 1st, 3rd and 6th month after injection

Using the musculoskeletal sonogram to measure the cross-sectional area of the median nerve before treatment and multiple time frame after treatment.

Change from baseline of conduction velocity, amplitude of median nerve on 2nd week, 1st, 3rd and 6th month after injection

Antidromic sensory nerve conduction velocity of the median nerve before treatment and multiple time frame after treatment.

Inclusion Criteria: Age between 20-80 year-old. Diagnosis was confirmed using an electrophysiological study Exclusion Criteria: Cancer Coagulopathy Pregnancy Inflammation status Cervical radiculopathy Polyneuropathy, brachial plexopathy Thoracic outlet syndrome Previously undergone wrist surgery or steroid injection for CTS

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