Carpal tunnel syndrome (CTS) is the most prevalent peripheral nerve entrapment of upper limb. Typical symptoms comprise pain, numbness or tingling of the thumb and index, middle or ring fingers. Thumb weakness and decreased grip strength can occur in the later stage. Currently treatments included physical modalities (low power laser, transcutaneous electrical nerve stimulation, ultrasound), medication, splinting, injection and surgery. Ultrasound guided intracarpal hydro-dissection of median nerve had been proposed based on its accurate localization, while the injectates were diverse. Corticosteroid has been widely used for CTS for decades. However, growing evidences suggested that 5% dextrose, normal saline, platelet rich plasma injection also have therapeutic effects on alleviating CTS symptoms. Among the injectates, a single 5% dextrose injection could be considered as a substitute of corticosteroid based on its long term effect up to six months. However, the clinical efficacy of 5% dextrose injection has not validated by the further study. The investigators aim to compare the therapeutic effect of 5% dextrose injection with corticosteroid injection in patients with CTS, up to 12 weeks follow up.

Introduction:

Carpal tunnel syndrome (CTS) is the most prevalent peripheral nerve entrapment of upper limb. Typical symptoms comprise pain, numbness or tingling of the thumb and index, middle or ring fingers. Thumb weakness and decreased grip strength can occur in the later stage. Currently treatments included physical modalities (low power laser, transcutaneous electrical nerve stimulation, ultrasound), medication, splinting, injection and surgery. Ultrasound guided intracarpal hydro-dissection of median nerve had been proposed based on its accurate localization, while the injectates were diverse. Corticosteroid has been widely used for CTS for decades. However, growing evidences suggested that 5% dextrose, normal saline, platelet rich plasma injection also have therapeutic effects on alleviating CTS symptoms. Among the injectates, a single 5% dextrose injection could be considered as a substitute of corticosteroid based on its long term effect up to six months. However, the clinical efficacy of 5% dextrose injection has not validated by the further study. Whether repeated injection could expand the treatment effect was undetermined. The investigators aim to compare the therapeutic effect repeated 5% dextrose injection with corticosteroid injection in patients with CTS, up to 12 weeks follow up.

Material and methods:

Participants: 60 adult patients (>20 year olds) with carpal tunnel syndrome, recruited from outpatient clinic.

Inclusion criteria: Presenting with CTS symptoms, including nocturnal, postural, or motion-associated paresthesias +/- pain of the median nerve distribution area in the subjective hand. Confirmed Electrophysiological confirmed median neuropathy at the wrist with mild to moderate degree. Persistent symptoms for more than 3 months

Exclusion Criteria: Patients cervical radiculopathy, polyneuropathy, brachial plexopathy, thoracic outlet syndrome. Recent corticosteroid injection to the carpal tunnel within 6 months.

Thenar muscle atrophy. Previous history of carpal tunnel surgical release. History of wrist trauma. Regular use of systemic nonsteroidal anti-inflammatory drugs, corticosteroids or diuretics. Pregnancy. Cognitive impairment.

Objective:

The aim of this study is to compare the treatment effect of repeated 5 mL 5% dextrose with 5mL triamcinolone acetonide injection in patients with CTS.

Detail of the intervention The study is designated as randomized, double blinded, and parallel experiment. The randomization was decided by random table in block of 4.

Repeated ultrasound guided injection intracarpal median nerve hydro-dissection with 5 mL 5% dextrose (Group B) or 5mL triamcinolone acetonide injection (Group A) in patients with CTS.

The regimen was shown as below:

Group A: 1st injection (0 week): 40mg triamcinolone acetonide (40mg/mL) with 4mL normal saline, 2nd injection (6 week): 5 mL normal saline Group B: 1st injection (0 week): 5 mL 5% dextrose, 2nd injection (6 week): 5 mL 5% dextrose

Skin infiltration with local anesthetic (lidocaine cream) at the needle insertion site was performed before the injection. Then injection was performed after sterilization. The equipment for ultrasound-guided injection will be high-resolution ultrasound machine with the linear probe.

Outcome measurement:

Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) and Visual analogue scale (VAS) before 1st injection, before 2nd injection (6-week) and 12-week after first injection.

Electrophysiological evaluation (amplitude and distal latency of median nerve compound motor action potential and sensory nerve action potential); cross-sectional area of median nerve at carpal tunnel inlet, were evaluated before and 12-week after 1st injection.

Global assessment of treatment was evaluated at before 2nd injection (6-week) and 12-week after first injection.

Statistical analysis:

Continuous variables Student's t test: fit assumption of normal distribution Mann-Whitney test: does not fit the assumption of normal distribution Categorical variables (1) Chi-square test (2) Fisher exact test: sparse data (3)Repeated-measures analysis of variance (ANOVA) was used to evaluate the effect of injection with post-hoc Bonferroni test to evaluate intra-group data at different time-frame

Keywords: Hydro-dissection, corticosteroid, dextrose, carpal tunnel syndrome

Inclusion Criteria:

• Presenting with carpal tunnel syndrome symptoms, including nocturnal, postural, or motion-associated paresthesias +/- pain of the median nerve distribution area in the subjective hand
• Confirmed Electrophysiological confirmed median neuropathy at the wrist with mild to moderate degree
• Persistent symptoms for more than 3 months

Exclusion Criteria:

• Patients with suspicious of CTS mimic condition, including cervical radiculopathy, polyneuropathy, brachial plexopathy, thoracic outlet syndrome
• Recent corticosteroid injection to the carpal tunnel within 6 months
• Thenar muscle atrophy
• Previous history of carpal tunnel surgical release
• History of wrist trauma
• Regular use of systemic nonsteroidal anti-inflammatory drugs, corticosteroids or diuretics
• Pregnancy
• Cognitive impairment