Change in Skin Surface Temperature at the Posterior Neck When Using Acupuncture at Houxi Acupoint in Healthy Volunteers.

Introduction The use of acupuncture has been suggested for the treatment of neck pain. Recently, a large body of evidence demonstrated that acupuncture has an effect on microcirculation in pain regions, but the exact mechanism remains unclear. This study aims to evaluate the skin surface thermographic changes in the posterior neck associated with manual acupuncture at the Houxi (SI-3) acupoint. Methods Sixty healthy volunteers of both genders, aged 18 to 30 years, were randomly determined into two groups: left acupuncture (Group A) and right acupuncture (Group B). Each group underwent two sessions with a seven-day interval. The first session involved acupuncture at the control Yuji (LU-10) acupoint, while the second session featured acupuncture at the SI-3 acupoint. Skin temperature at the posterior neck was measured by using an infrared thermal camera (FLIR C5™, FLIR® Systems, Inc., Wilsonville, OR, USA) at five time points with 5-minute intervals. Results There were statistically significant increases in posterior neck skin surface temperature (p < 0.05) during acupuncture at both the left and right SI-3 acupoints, but no significant change was observed during acupuncture at the left and right LU-10 acupoints. Furthermore, acupuncture at the SI-3 acupoint on either hand increased posterior neck skin surface temperature without a statistically significant difference (p > 0.05). Conclusion We observed that applying acupuncture at the SI-3 acupoint increased the skin surface temperature of the posterior neck area. Furthermore, the SI-3 acupoint exhibits a uniform impact on the posterior neck area's skin surface temperature, regardless of the side chosen for acupuncture.