["Sham Needle"--Design and Application of A Double-blind Placebo Needle Assembly]

The blind study design, particularly the double-blind study design is a very important method for diminishing placebo effect and reducing bias in clinical medical trial. Enlightened by Streitberger's and Park's sham needle design, the authors of the present paper introduce a newly designed sham needle device (Yan's sham-needle) for controlled double-blind trials of acupuncture. This sham needle device consists of needle, tube and base. The bottom of the tube is completely sealed and it can never arouse any invasive stimulation on the subject's skin when the sham needle is downward pressed on the body surface. Meanwhile, this sham device is filled with sponge which is able to simulate soft tissues of the acupoint area. By combining words suggestions or hints before trials and the same shape as verum device, this sham-needle device reduces the risk of blind-breaking and makes it possible to conduct controlled double-blind trials. Primary practice showed that this device may provide a new and practical tool for researching the placebo effect of acupuncture therapy.