Effect of bidirectional rotation of an acupuncture needle at LI10 on acupuncture needle sensation and experimentally-induced contact heat pain in healthy human volunteers.

INTRODUCTION: There is insufficient evidence of a relationship between acupuncture needle sensations (de qi) and hypoalgesia. The aim of this study was to investigate the effects of bidirectional needle rotation at LI10 on acupuncture needle sensations and heat pain thresholds. METHODS: Twenty-two healthy participants received one acupuncture needle at LI10 with bidirectional rotation of the needle in one experimental session and one acupuncture needle at LI10 with mock rotation in a separate session, in a randomised order. Measurements of heat pain thresholds were taken before needle insertion, during needle retention and 15 min after needle removal. At each measurement time point, participants rated needle sensations using the Massachusetts Acupuncture Sensation Scale (MASS) and a visual analogue scale (VAS) of overall intensity of needle sensation. RESULTS: Bidirectional needle rotation produced significantly higher scores for VAS, MASStotal, MASSpain and MASSsensation compared with mock rotation (all p<0.001). There were significantly higher pain thresholds relative to pre-intervention baseline during (p=0.014) and after (p<0.001) bidirectional needle rotation but not during (p=0.1) or after (p=0.62) mock bidirectional needle rotation. Bidirectional needle rotation increased the pain threshold relative to baseline 15 min after the needles were removed (p=0.009). A significant but low correlation between needle sensation and change in pain threshold after needling was only found when data from mock and rotation interventions were combined. CONCLUSIONS: Needle rotation increases the magnitude of hypoalgesia. There is tentative evidence that needle sensation may be associated with the amount of change in pain threshold.