The selection of dermatomes for sham (placebo) acupuncture points is relevant for the outcome of acupuncture studies: a systematic review of sham (placebo)-controlled randomized acupuncture trials

Abstract

<jats:sec><jats:title>Background:</jats:title><jats:p> Many randomized controlled trials (RCTs) of acupuncture reveal no significant differences between acupuncture and so-called placebo acupuncture. There is a strong tendency to replace the term “placebo” by the term “sham,” because any needling stimulates a certain physiological response. However, neither concept accounts for the great diversity of results in RCTs comparing verum acupuncture and sham (placebo) acupuncture. Some trials have shown little or no difference, while other studies have found statistically significant differences. </jats:p></jats:sec><jats:sec><jats:title>Objective:</jats:title><jats:p> Verum acupuncture and sham (placebo) acupuncture may achieve similar results to the extent that they share active constituents. We identified these common active constituents as dermatomes: the segmental structure of the human body. In our study, we tested the hypothesis that the more verum and sham (placebo) acupuncture share the same dermatomes, the closer the clinical outcomes will be, and vice versa. </jats:p></jats:sec><jats:sec><jats:title>Methods:</jats:title><jats:p> All major databases were searched for RCTs that tested acupuncture versus sham (placebo) acupuncture. The dermatome charts of Hansen and Schliack were used to verify verum and sham (placebo) needling locations. Reported clinical outcomes were assessed in relation to the percentage of overlap between the dermatomes stimulated by acupuncture and sham (placebo) acupuncture. </jats:p></jats:sec><jats:sec><jats:title>Results:</jats:title><jats:p> Our literature search yielded a total of 1738 references. Thirty-four studies met the inclusion criteria. The effects of sham (placebo) acupuncture varied according to the dermatomes stimulated: high overlap with those stimulated by verum acupuncture resulted in almost identical efficacy, while low overlap resulted in significant differences in efficacy. Clinical outcomes were similar when verum acupuncture and sham (placebo) acupuncture shared the same dermatomes (p &lt; 0.01). </jats:p></jats:sec><jats:sec><jats:title>Discussion:</jats:title><jats:p> The findings of this review confirm our hypothesis. Acupuncture studies that employed verum and sham locations on overlapping dermatomes helped to create a mediocre to negative picture of acupuncture’s efficacy. The segmental structure of the body with its interconnected reflex system offers an additional neurophysiological explanation for the effectiveness of acupuncture applied to structures segmentally innervated by the spinal and visceral nervous system. Further comparative acupuncture studies should be based on knowledge of segmental anatomy. In testing verum acupuncture versus sham acupuncture, the chosen sham acupuncture needling locations should be situated on non-overlapping dermatomes. </jats:p></jats:sec>

Neuroplasticity of Acupuncture for Stroke: An Evidence-Based Review of MRI

“…This review found that different SA types also have distinct brain responses. The overlapping dermatomes between nonacupoints and verum acupoints may explain this phenomenon, as the segmental structure of the body and its interconnected reflex system offers neurophysiological effects [85]. Therefore, the selection of proper SA is critical in determining the efficacy of acupuncture.…”

Immediate acupuncture with GB34 for biliary colic: protocol for a randomised controlled neuroimaging trial

“…However, a recent review indicates that sham acupuncture and verum acupuncture have almost identical efficacy when the dermatomes that are stimulated highly overlap. 74 The present study may help to test these authors' arguments. Because the pain of patients with BC is so severe that they can tolerate fNIRS imaging for only a short time, acupuncture with a short-time needle retention time (10 min and 30 s) will be chosen after the pilot study.…”

Progress of Acupuncture Therapy in Diseases Based on Magnetic Resonance Image Studies: A Literature Review

“…This may be explained by similar segmental innervations in HC. As shown by a recent systematic review (Ots et al, 2020 ), VA and SA have similar therapeutic effects due to their position in overlapping dermatomes, which partly explain several previous clinical studies (Assefi et al, 2005 ; Hinman et al, 2014 ) that showed no significant difference in the effect of VA compared with SA. Thus, to obtain reliable results, the location of the needles selected for SA should be at non-overlapping cutaneous segments based on the knowledge of segmental anatomy.…”