according to the intergroup analysis carried out in the same period, the impact of pain was significantly lower in the treatment group in comparison with the placebo one. In the follow-up evaluation, there was a slight increase in this parameter in the treatment and placebo groups, with the former showing the highest variation, indicating that the continuity of treatment is decisive to keep an adequate mobility. Table 3 reveals the relationship between pain threshold and intensity of the mechanical stimulus applied using a digital algometer. The results show that this variable did not change among groups. 6 www.ee.usp.br/reeusp Effects of auricular acupuncture on chronic pain in people with back musculoskeletal disorders: a randomized clinical trial Rev Esc Enferm USP · 2019;53:e03418 DISCUSSION The present study demonstrated that the AA based on the principles of traditional Chinese medicine produced positive effects on chronic back pain intensity and relief, decreasing the impact of this condition on daily activities. The main underlying mechanisms of these effects relate to 1) the analgesia induced by acupuncture; 2) the activation of descending pathways of the inhibitor system of pain control; and 3) the expectations of patients regarding pain relief, that is, the placebo effect(19-22). The acupuncture-induced analgesia is, at least partially, mediated by sensory-discriminative and affective-social aspects of touch that activate the “gate theory” for pain control(19). According to this model, the concomitant and quick conduction of discriminative spatial information through Aβ type myelinated fibers surpasses the pain-related information transported by C type fibers, which are unmyelinated and provide slow conduction. Additionally, conduction through type C fibers may also be influenced by emotional and motivational aspects related to the procedure(20). Another important aspect that must be emphasized is the design implemented in the present study. The experiment included not just a group of people who received regular treatment, but also a control group, whose members received no intervention, and a placebo group, whose participants received sham AA. An additional positive characteristic of the present investigations was its significant period of follow-up, which lasted 15 days and contributed to discern the efficacy of the intervention, especially between the treatment and placebo groups. This standardization strengthens the findings, although some of the results may be attributed to the placebo effect of the AA, which is inherent to the patients’ expectations regarding the therapy and modulates the perception of pain(23). It is known that a soft touch is enough to active mechanoreceptors coupled to slow-conduction afferent myelinated type C Table 3 – Intragroup and intergroup analyses of pain threshold expressed as mean ± standard deviation, with a confidence interval of 95%, for the three studied groups at three different moments – Alfenas, MG, Brazil, 2016. Groups Evaluations Initial Final Follow-up Treatment (n The efficacy of acupuncture in the management of musculoskeletal pain Reviewer Natalie Hardaker and Mark Ayson Date Report Completed August 2011 Important Note: • This report is not intended to replace clinical judgement, or be used as a clinical protocol. • A robust evidence-based review of clinical guidelines, systematic reviews and high quality primary evidence relevant to the focus of this report was carried out. This does not however claim to be exhaustive. • The document has been prepared by the staff of the research team, ACC. The content does not necessarily represent the official view of ACC or represent ACC policy. • This report is based upon information supplied up to 31st July 2011 Purpose The purpose of the report is to; • Briefly describe traditional Chinese medicine (TCM) acupuncture and western medical acupuncture • Report the efficacy of acupuncture for the treatment of injury-related spine, shoulder, knee & ankle conditions • Report the comparative efficacy of acupuncture when considering alternative conservative treatment interventions for the spine, shoulder, knee & ankle • Report any adverse reactions cited in the literature. Scope This report will be restricted to acupuncture involving various modes of needling (including electroacupuncture) for musculoskeletal pain from knee, spine, shoulder and ankle injuries. Treatment modalities of TCM like cupping, scraping, Chinese massage, and herbalism will not be addressed. A c c i d e n t C o m p e n s a t i o n C o r p o r a t i o n Page 1 No distinction will be made between traditional Chinese medical acupuncture and western medical acupuncture Summary Message The evidence for the effectiveness of acupuncture is most convincing for the treatment of chronic neck and shoulder pain. In terms of other injuries, the evidence is either inconclusive or insufficient. The state of the evidence on the effectiveness of acupuncture is not dissimilar to other physical therapies such as physiotherapy, chiropractic and osteopathy. Key findings General • There is insufficient evidence to make a recommendation for the use of acupuncture in the management of acute neck, back or shoulder pain • There is emerging evidence that acupuncture may enhance/facilitate other conventional therapies (including