Investigation of the Effects of Needling the Acupuncture Point Houxi (SI 3) on Pressure Pain Threshold, Needling Sensation and Needling Pain in Healthy Participants

Abstract

Background:During the past decades, there has been a surge in prescribing opioids for pain related conditions, the “opioid epidemic”. It is critical for researchers and clinicians to explore other non-pharmacological approaches to manage pain instead of relying on opioid analgesics. Acupuncture could be an effective tool to modulate pain.

Since 1999, studies on the effect of acupuncture on pressure pain threshold (PPT), at the University of Technology Sydney (UTS), have been conducted. The effects of the acupuncture to the acupoint LI 4 (Hegu) on PPT, the strength and quality of needling sensation (deqi) and the intensity of needling pain have been investigated by researchers from the UTS acupuncture group. However, the effects of another acupoint, Small Intestine 3 (SI 3 -Houxi) a commonly used acupoint for the treatment of various painrelated conditions has not been explored for its effect on PPT and deqi.

Aim:The primary aim of this study was to investigate the effects of needling the acupoint SI 3 in healthy people on:

1. Regional PPT at ten sites (SI 11^R , SI 11^L , GV 4, GV 14, HT 7^R , HT 7^L , BL 60^R , BL 60L , GB 21^R , GB 21^L ) following three different interventions - SI3m⁺ , SI3mand SL; 2. The strength and quality of needling sensation (deqi) reported by subjects; and 3. The intensity of pain associated with the intervention.

Methods: Prior to commencing the study a systematic review was undertaken on the clinical use of acupoint SI 3 and PPT in acupuncture clinical studies. Following the reviews, this prospective study was designed as a randomised, double-blind, three-arm, and cross-over experimental study to investigate the effects of needling SI 3 on regional PPT, deqiand needling pain.

Methods: Prior to commencing the study a systematic review was undertaken on the clinical use of acupoint SI 3 and PPT in acupuncture clinical studies. Following the reviews, this prospective study was designed as a randomised, double-blind, three-arm, and cross-over experimental study to investigate the effects of needling SI 3 on regional PPT, deqi and needling pain.

Results: For SI3m⁺and SI3minterventions, the post intervention mean % PPT scores were significantly elevated compared with SL (p < 0.001). SI3m+ statistically significantly elevated PPT% comparing to SI3m- (p < 0.001). The mean needle sensation and pain scores were similar for the two needling interventions, but both increased when comparing to SL. The subjects’ anxiety and tension levels were not significantly different across the interventions.

Conclusions:Both intervention and site of needling were found to be important contributors to the effects on regional PPT in healthy participants. This study has provided findings that support the belief that obtaining deqi during acupuncture is necessary for eliciting a pain modulating effect. Needling pain had no correlation with PPT.