Clinical Implications of Real-Time Visualized Ultrasound-Guided Injection for the Treatment of Ulnar Neuropathy at the Elbow: A Pilot Study

OBJECTIVE To investigate the feasibility of ultrasound (US)-guided steroid injection by in-plane approach for cubital tunnel syndrome (CuTS), based on symptomatic, morphologic and electrophysiological outcomes. METHODS A total of 10 patients, who were clinically diagnosed as CuTS and confirmed by an electrodiagnostic study, participated in this study. US-guided injection into the cubital tunnel was performed with 40 mg triamcinolone and 2 mL of 1% lidocaine. Outcomes of the injections were evaluated at pre-injection, 1st week and 4th week after injection. Visual analog scale, self-administered questionnaire of the ulnar neuropathy at the elbow (SQUNE), and McGowan classification were used for clinical evaluation. Cross-sectional area of the ulnar nerve by US and the electrophysiological severity scale through a nerve conduction study were utilized in the evaluation of morphologic and electrophysiological changes. The cross-sectional area of the ulnar nerve was measured at 3 points of condylar, proximal, and distal level of the cubital tunnel. RESULTS No side effects were reported during the study period. The visual analog scale and cross-sectional area showed a significant decrease at 1st week and 4th week, as compared to baseline (p<0.05). The electrophysiological severity scale was significantly decreased at the 4th week, as compared with baseline and 1st week (p<0.05). Among the quantitative components of the scale, there were statistically significant improvements with respect to the conduction velocity and block. CONCLUSION The new approach of US-guided injection may be a safe tool for the treatment of CuTS. Symptomatic and morphologic recoveries preceded the electrophysiological improvement.