Efficacy and Safety of Acupuncture Combined with Traditional Chinese External Therapy for the Treatment of Scalenus Anticus Syndrome: A Systematic Review and Meta-Analysis.

This study systematically evaluated the efficacy and safety of acupuncture combined with traditional Chinese medicine (TCM) external therapy for Scalenus Anticus Syndrome (SAS) and explored the certainty and limitations of the current evidence. A comprehensive search of eight electronic databases identified eligible randomized controlled trials (RCTs), and 11 RCTs involving 746 patients met the inclusion criteria. All included studies were conducted in China and enrolled patients with neurogenic SAS. Meta-analysis demonstrated that acupuncture combined with TCM external therapy significantly improved overall clinical effectiveness compared with control interventions (RR = 1.21, 95% CI: 1.13-1.29), reduced pain intensity as reflected by lower visual analogue scale scores (MD = -1.04, 95% CI: -1.58 to -0.50), and decreased recurrence rates (RR = 0.32, 95% CI: 0.14-0.70). Sensitivity analyses supported the robustness of the pooled findings, whereas Egger's test indicated potential publication bias. Subgroup analyses were conducted to explore sources of heterogeneity in pain outcomes; however, no statistically significant subgroup differences were identified. Safety evidence remained insufficient because only one study reported mild adverse reactions and most studies did not document adverse events. These findings suggest that acupuncture combined with TCM external therapy may provide clinically meaningful benefits for patients with SAS. However, the overall certainty of evidence was low because of methodological limitations, insufficient safety reporting, publication bias, and heterogeneity across studies. Further high-quality multicenter randomized controlled trials with standardized outcome measures and long-term follow-up are required to confirm efficacy and safety.