Efficacy and safety of manufactured Chinese herbal formula for cervical radiculopathy: a systematic review with meta-analysis and trial sequential analysis.

Background: Clinical trials have been widely reported for the application of manufactured Chinese herbal formula (MCHF) in patients with Cervical Radiculopathy (CR). Existing published systematic reviews are confined to assessing the therapeutic efficacy of individual MCHF types in the management of CR, whereas a comprehensive, holistic evaluation of both efficacy and safety outcomes across the full spectrum of MCHF remains lacking. Objective: To assess the efficacy and safety of MCHF for CR. Methods: We searched six databases and three registries from inception to 30 September 2024. Eligible randomized controlled trials investigating the efficacy of MCHF for CR were included. Data extraction, methodological assessment, and meta-analyses were conducted according to the Cochrane standards. Results: We included 14 studies, covering 8 types of MCHF with a total of 1,576 participants. MCHF may reduce the pain of VAS in CR. In subgroup meta-analysis, MCHF may be more efficacious in relieving pain than the placebo. MCHF combined with conventional oral drugs were more efficacious than conventional oral drugs alone. Trial sequential analysis (TSA) indicated that the sample sizes were adequate to confirm the reliability of the aforementioned findings. No significant difference in therapeutic efficacy was observed between MCHF and conventional oral medications, but TSA indicated that further large-scale RCTs are required to validate these results. In terms of the Neck Disability Index (NDI), the intervention group showed potentially superior functional improvement compared with the control group in add-on and placebo-controlled trials; however, its efficacy relative to conventional oral drugs remained unclear. Regarding adverse events, no significant between-group differences were detected in add-on and head-to-head trials, whereas the intervention group had a higher incidence of adverse events than the control group in placebo-controlled trials. Conclusion: MCHF may be efficacious in the pain and neck disability in treatment of CR, and may not exhibit significant differences from conventional oral drugs. A certain incidence of adverse events was observed in MCHF-treated groups. However, the certainty of evidence is low/very low, with safety evidence being particularly weak. Further high-quality RCTs are warranted to verify the efficacy and safety of MCHF. Systematic review registration: [https://www.crd.york.ac.uk/PROSPERO/view/CRD42024605787], identifier [#CRD42024605787].