A Placebo Acupuncture Device for Standardized Acupuncture Control Procedures

Reliable placebo controls are difficult to implement in acupuncture trials because skin penetration, insertion direction, tactile feedback, and operator-participant interactions can reveal treatment allocation. This article describes a predefined-angle placebo acupuncture device designed to standardize a penetrating real-needle procedure and a nonpenetrating pressure-contact control while supporting allocation concealment for participants and treating acupuncturists. The system combines an opaque sleeve, matched 25 mm external needle exposure, a 0.35 mm x 65 mm sharp real needle or a 0.35 mm x 42 mm blunt placebo needle, internal resistance-generating material, and a medical-grade adhesive pad. In the present feasibility study, Yintang (DU29; historically also designated EX-HN3 in some international nomenclature systems) was treated using a predefined 30° oblique configuration, whereas right Hegu (LI4) was treated using a perpendicular configuration. At full advancement, the real needle penetrated approximately 25 mm, whereas the blunt placebo tip extended approximately 2 mm beyond the adhesive pad and compressed the skin without penetration. In 60 healthy volunteers randomized 1:1, no statistically significant between-group difference in VAS-rated needling discomfort was observed (4.63 ± 1.56 vs. 4.97 ± 1.67; t = -0.7976, p = 0.4283). Agreement between actual allocation and participant guesses was minimal (Cohen's κ = 0.033, 95% CI: -0.218 to 0.285), and agreement with acupuncturist guesses was low (κ = 0.133, 95% CI: -0.117 to 0.384). Group-specific Bang Blinding Index confidence intervals all included zero, although the relatively wide intervals did not exclude partial unblinding. These findings provide preliminary estimates of treatment-guessing behavior rather than confirmation of successful blinding. The placebo configuration should be regarded as a nonpenetrating pressure-contact control, not a physiologically inert placebo.