Effectiveness of ultrasound guided corticoanesthetic injection in carpal tunnel syndrome treatment comparing two different injection sites. Single-blind randomized trial.

Carpal tunnel syndrome (CTS) is the most common nerve entrapment neuropathy. Six placebo-controlled trials with 393 participants proved corticosteroid injection to be effective in symptom relief. However, all injections were palpation-guided. Therefore, the exact injection site was uncertain. Although three studies comparing palpation and ultrasound (US) guided CTS injection showed US superiority, the optimal injection site for the injectate delivery remains unclear. Some authors believe in thinning of the flexor tenosynovium as the mechanism of the median nerve decompression, and therefore recommend injection between the tendons, away from the nerve. Other authors stress the importance of hydrodissection and direct contact of the injectate with the nerve and suggest injection targeting the median nerve. According to our best knowledge, no study comparing different injection sites for a corticosteroid delivery in CTS has been published in English written literature. The objective of this study was to determine the optimal target site for the corticosteroid delivery in CTS injection.

Inclusion Criteria:

• primary idiopathic CTS
• symptoms of classic or probable CTS (numbness or tingling in at least 2 of the 4 radial fingers)
• unsuccessful 1-month treatment with wrist splinting
• nerve conduction test results that showed median neuropathy at the wrist

Exclusion Criteria:

• previous steroid injection
• diabetes mellitus,
• thyroid disorder
• inflammatory disease
• polyneuropathy
• current pregnancy
• previous carpal tunnel surgery
• severe illness
• inability to respond to questionnaires

Publication in the relevant journal