Clinical Results and Complications of Shoulder Manipulation under Ultrasound-Guided Cervical Nerve Root Block for Frozen Shoulder: A Retrospective Observational Study.

INTRODUCTION

Manipulation under ultrasound-guided fifth and sixth cervical nerve root block (MUC) is a recognized form of treatment for patients with persistent frozen shoulder (FS). This study aimed to investigate the confirmatory hypothesis testing that the MUC has a significant clinical effect on FS refractory to conservative treatments and to assess its adverse events.

METHODS

This is a retrospective observational study on patients with FS treated in the past 8 years. Although 77 patients were eligible for this study, only 68 were enrolled. The patients were evaluated immediately before the MUC and at 1, 3, and 6 months after with the use of the Japanese Orthopaedic Association shoulder score. Simultaneously, ranges of motion of the affected shoulder were measured in two directions: forward flexion and external rotation. A paired t test or a Wilcoxon signed-rank test was used to compare differences in outcomes between before and 6 months after MUC. We also assessed any adverse events during and after the MUC.

RESULTS

Regarding the primary outcome, confirmatory testing showed statistically significant improvements in every outcome value at 6 months after MUC (p < 0.001). In terms of adverse events, two patients (2.9%) had vasovagal reflex, one (1.5%) had a panic attack during the block procedure, and a 72-year-old female patient (1.2%) had an avulsion fracture of the inferior glenoid during the manipulation procedure, although all of them recovered spontaneously without any residual functional impairment.

CONCLUSION

The results showed that significant clinical effects of the MUC on FS were observed through a confirmatory analysis with a sufficient sample size. However, several complications that could occur during the block and manipulation procedures should be considered.