The Efficacy of Shear Wave Elastography in Evaluating Treatment Response to US-Guided Steroid Injection in Patients with Carpal Tunnel Syndrome.

Rationale And Objectives: This study aimed to evaluate the efficacy of ultrasound (US)-guided local steroid injection in carpal tunnel syndrome (CTS) using shear wave elastography (SWE).

Materials And Methods: A total of 47 wrists from 41 patients diagnosed with mild to moderate idiopathic CTS, based on clinical and electrophysiological criteria, were enrolled between June and October 2024. All participants underwent US-guided local steroid injection. Pre- and post-injection assessments included measurement of the median nerve's cross-sectional area (CSA) and evaluation of its elasticity through shear wave velocity (m/s) and Young's modulus (kPa). Clinical outcomes were assessed before and 6 weeks after the injection using the Visual Analog Scale (VAS), the Boston Questionnaire-Symptom Severity Scale (BQ-SSS), and the Boston Questionnaire-Functional Status Scale (BQ-FSS). The clinical scores before and after the injection were compared to the corresponding US and SWE measurements.

Results: Prior to steroid injection, the median nerve CSA was 15.53±4.28mm², shear wave velocity was 4.01±0.27m/s, and Young's modulus was 49.03±6.90kPa. Six weeks following the injection, significant reductions were observed in these parameters, with CSA decreasing to 12.04±2.59mm², shear wave velocity to 3.03±0.22m/s, and Young's modulus to 28.09±4.16kPa (p<0.001 for each). Clinical scores also demonstrated significant improvement, with VAS decreasing from 7.12±1.09 to 2.91±0.86, BQ-SSS from 38.36±4.97 to 21.36±3.50, and BQ-FSS from 23.72±3.81 to 13.27±1.65 (p<0.001 for all).

Conclusion: US-guided steroid injection improves clinical symptoms and reduces the CSA and nerve elasticity in CTS patients six weeks post-treatment.