Objective: To compare the outcomes of ultrasound-guided vs direct approach corticosteroid injection in patients with idiopathic carpal tunnel syndrome.
Methods: A double-blind randomized controlled study. Wrists affected by carpal tunnel syndrome were randomized to the ultrasound-guided (n = 22 wrists) or direct approach injection group (n = 17 wrists) before receiving 1 ml Betamethasone. Outcome measures were physical findings and electrodiagnostic parameters assessed at 1, 3 and 6 months after injection. Complications were also recorded.
Results: Both groups showed improvement through-out the follow-up period after injections, in physical findings and in most electrodiagnostic parameters (all p<0.05). The ultrasound-guided injection group showed greater improvements in the Semmes-Weinstein Monofilament test result (p = 0.004), sensory nerve conduction velocity (p = 0.038), and digit-4 comparison study result (p = 0.046). Three wrists with weakness were found in the direct approach injection group, yet none were noted in the ultrasound-guided injection group (p=0.040).
Conclusion: Both ultrasound-guided and direct approach corticosteroid injection protocols improved clinical symptoms and signs, physical function, and most electrodiagnostic parameters of patients with carpal tunnel syndrome throughout the follow-up period. However, the ultrasound-guided injection group showed greater improvements in the Semmes-Weinstein Monofilament test, sensory nerve conduction velocity, and digit-4 comparison study.