Ultrasound-guided perineural vs. peritendinous corticosteroid injections in carpal tunnel syndrome: a randomized controlled trial.

Background: Corticosteroid injections are proven to be effective in the management of carpal tunnel syndrome (CTS); however, the optimal injection site still remains unclear.

Aim: The aim of this study is to compare the efficacy of perineural vs. peritendinous target sites for corticosteroid injection in CTS.

Design: A randomized, single-blind, controlled trial.

Setting: Outpatients, tertiary care center.

Population: Forty-six patients were equally randomized into two intervention groups as group A (18 female and five male patients; mean age: 50.0±15.9 years; mean symptom duration: 5.9±3.3 months) and group B (19 female, four male patients; mean age: 54.3±15.0 years; mean symptom duration: 5.9±4.7 months).

Methods: Methylprednisolone acetate (40 mg) and 1 mL of 1% trimecaine hydrochloride was injected next to the median nerve (group A) or among flexor tendons away from the nerve (group B) under ultrasound (US) guidance. The visual analogue scale was used as the primary outcome measure, and the symptom severity scale and functional status scale of the Boston Carpal Tunnel Questionnaire were used as the secondary subjective outcome measures. Two-point discrimination, grip strength, cross-sectional area, and distal motor latency were assessed as objective outcome measures. The data were collected at baseline and at 2, 6 and 12 weeks after the injection.

Results: Both groups showed improvement in subjective and objective measures at 2 weeks following the injection - also maintained up to 12 weeks during the follow-up (P<0.05). However, no difference was observed between the two groups (P<0.05). No serious adverse effects were observed in either group.

Conclusions: Both intervention techniques seem to be effective and safe in the conservative treatment of CTS.

Clinical Rehabilitation Impact: Based on this study results, it might be noteworthy that physicians can opt for perineural or peritendinous injections without compromising the treatment efficacy and safety. Herewith, US guidance is, for sure, necessary for performing safe and accurate injections.