Background Traditional Chinese medicine (TCM) meridians and points run vertically, reflecting their function in the Zhang-Fu system (meridian pattern). However, the trunk’s spinal nerves show a traverse orientation, or a ‘horizontal pattern’.
Objective The aim of the present work was to evaluate, via a cognitive quasiexperiment, whether the clinical indications of the points on the trunk are associated with their meridian function or with their innervation and visceral–somatic connection.
Methods The points in each dermatome of the trunk were considered crosswise, regardless of their meridians. The clinical indications for each point were differentiated into two mutually exclusive categories: (a) vertical distribution effect (VDE) or ‘meridian pattern’, when indications were quite different regarding the indications for the other points on the dermatome; and (b) transverse distribution effects (TDE) or ‘horizontal pattern’, represented by mainly local or segmental indications except for Shu-Mu points. After observing that the proportions between both categories often exceeded 60% in pilot samples, 60% was adopted as the reference value.
Results A total of 22 dermatomes accommodated 148 points with 809 indications, of which 189 indications (23.4%) exhibited VDE features, whereas 620 (76.6%) exhibited TDE features.
Conclusions A TDE/VDE ratio of 3 : 1 implies that the clinical indications for the points of any dermatome on the torso are similar, regardless of their meridians, and suggests that most of the indications for trunk points involve a ‘horizontal pattern’ due to their neurobiological nature. These findings may help in understanding acupuncture's neurobiology and clarify some confusing results of clinical research, for example, excluding sham acupuncture as an inert intervention for future clinical trials.
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Acupuncture clinical research has not been free of pitfalls. Acupuncture randomised controlled trials (RCTs) often produce conflicting results. Nevertheless, many studies have found that treated and control groups experience lasting relief of their symptoms in several contexts.1–10 Despite the abundant data that indicate the remarkable clinical performance of acupuncture in real settings and its superior performance when compared with waiting lists, the trend of conflicting results in RCTs has not substantially changed over time most likely due to methodological and affective discrepancies.11–21
Traditional Chinese acupuncture (TCA) imagines that ‘energy’ flows throughout the body in an intricate network of channels or meridians. Each meridian corresponds specifically to an organ or a viscus (Zhang-Fu), which determines its functional and clinical properties.22 However, neurobiology can be used to explain most of acupuncture's effects. In this study, we aimed to determine whether the segmental behaviour of acupuncture points on the trunk could explain some of the conflicting results from acupuncture RCTs.
In figure 1, a vertical pattern (the black and green dots) in the distribution of acupuncture points can be observed (here called a ‘meridian pattern’). According to TCA, the indications for each point reflect the clinical function of its respective meridian. Therefore, we would expect the points in any dermatome to have different indications that pertain to their meridians running across zones, which we term the vertical distribution effect (VDE).
In addition, another pattern can be detected in figure 1. The transverse distribution of the points on the dermatomes (the red dots) displays a ‘horizontal pattern’. Therefore, the orientation of the points would depend on the segmental architecture of the body, which parallels the symmetrical distribution of the spinal nerves and the vessels. In such an architecture, the somatic and visceral structures that are innervated by the same spinal segment behave as a whole; therefore, a disturbance in any such structure would impact the others.24 A random puncture at any location on a given dermatome would induce similar effects. Consequently, a set or group of points that pertain to a dermatome would have analogous indications depending on their underlying somatic–visceral connection, which would correspond with a neurobiologically derived effect.10 ,24 We have termed this the transverse distribution effect (TDE).
On this basis, a quasiempirical experiment was conducted to determine which effects are observed in real settings.
Materials and methods
A cognitive quasiexperiment
We used a simple cognitive strategy based on information from traditional Chinese medicine (TCM) sources to assess the classical postulates and the neuroanatomical correlates of acupuncture. Our objective was to evaluate the VDE, or ‘meridian pattern’, and the TDE, or ‘horizontal pattern’, of the points on the trunk to determine whether the clinical effects of acupuncture points depend on their meridian connections or on their innervation and underlying visceral–somatic substratum. Our null hypothesis was that the clinical indications of diverse points pertaining to different meridians of a given trunk zone will show relevant differences, reflecting a VDE.
This quasiexperimental study aimed to assess the VDE and TDE, using the clinical information in three officially recognised books on TCA.22 ,25 ,26 The clinical indications for each point are typically listed in acupuncture texts according to the numerical order of each meridian. However, in our study, we considered the points of each dermatome on the trunk crosswise, regardless of their affiliation with the various meridians that traversed each cutaneous band. In addition, the indications for the points were classified into the following two categories: (1) dependent on vertical distribution or (2) dependent on transverse distribution.
The points in each of the trunk dermatomes were accurately identified and enumerated according to clear topographical criteria obtained through a comparison of data from two anatomical acupuncture atlases: one from Shandong Medical College25 and another from Jean Bossy, a renowned neuroanatomist from the University of Montpellier.23 The set of points for each dermatome was tabulated for data collection.
In addition to the Chinese atlas, two authoritative books on acupuncture were consulted, which were supported by the Acupuncture Institute at the Academy of Traditional Chinese Medicine of Beijing and the Colleges of Traditional Chinese Medicine in Shanghai and Nanking.22 ,26 A comprehensive collection of indications and potential clinical effects were obtained for each of the points associated with the 22 trunk dermatomes (T1–S5) and were grouped into 22 tables.
The table for each dermatome contained a dermatome identification number, a list of points, a comprehensive set of indications for each point, two notation columns for indications of VDE or TDE, a subtotal column and a row total.
The clinical indications for each point were differentiated into the two mutually exclusive categories discussed below.
VDE or ‘meridian pattern’
(1) The indication for any point exhibited VDE features when it was unique, or at least very different from the indications for the other points on the dermatome. (2) The indication of any point demonstrated affinity with its meridian clinical function or corresponded with symptoms or signs that were systemic in nature.
TDE or ‘horizontal pattern’
Clinical indications, such as symptoms or signs that were local or regional in nature, represented a transverse effect that was associated with underlying neurobiology (the neural somatic–visceral substrate).
The assumed reference value was initially 50%, which indicated the predominance of one effect over the other. However, after observing that the proportions between both categories often exceeded 60% in pilot samples, 60% was adopted as the reference value. For each point: (1) a predominance of the VDE that exceeded 60% was assumed to be consistent with TCA postulates; and (2) a preponderance of the TDE that surpassed 60% was assumed to be compatible with the neurobiological perspective. For each dermatome: (1) a majority of VDE indications that exceeded 60% of its points would endorse the TCM model; and (2) a predominance of TDE indications that exceeded 60% of the points of a dermatome would validate the neurobiological perspective.
To facilitate the classification of the effects and simplify the visual appraisal process, indications that exhibited VDE features were recorded in bold in tables. Table 1 illustrates a typical table and the visualisation procedure that was used to distinguish between the nature of each indication and their respective points, using chi square test (the remaining tables can be seen on the web-only supplement).
In all, 22 dermatomes accommodated 148 points with 809 indications, of which 189 indications (23.4%) exhibited VDE features, whereas 620 (76.6%) exhibited TDE features.
A TDE/VDE ratio of approximately 3 : 1 was observed. The clinical indications for the points of any dermatome on the torso were similar, regardless of their meridians, which suggests that most of the indications for trunk points involve a ‘horizontal pattern’ due to their neurobiological nature. Therefore, the null hypothesis can be reasonably rejected. Trunk point effects depend on the overlapping distribution of sensorimotor and autonomic visceral innervations that originate from the segmental architecture of the body (see tables 2 and anatomical atlases 27 ,28). Therefore, our results suggest that the most significant factor for the clinical properties of each acupuncture point, in this context, could be the location of the point on a trunk dermatome.
The repetition of indications for the set of points found on the dermatomes of the torso may be due to the segmental array of the trunk, which functions as a whole. Therefore, needling the dermatome at any location or acupuncture point will induce a global response. Because needling impacts the singular structure of the peripheral, autonomic and central nervous systems,27 ,28 the non-specific healing potential of the body can be modulated by activating inbuilt self-regulating processes through neural, neurochemical, neuroendocrine and neuroimmune mechanisms29–34 whose integration occurs at the solitary tract nucleus and the medulla.35 ,36
Our results can elucidate certain ‘research paradoxes’ of acupuncture, such as the alleged specificity of points, which is not supported by neurobiology. In addition, our results can explain the inconsistency and non-specific behaviour of several distinctive points, such as the Back Shu points and the Front Mu points, regarding their respective Zhang-Fu.37 Curiously, our data show that their indications are indistinguishable from those of other nearby points. These points and the Head's areas share the same behaviour based on the body's neurobiological structure, as suggested by Western researchers.38 ,39 The interconnections and the diversity of responses induced by peripheral sensory stimulation (PSS) and the non-specific effects of this procedure may be too complex to be fully elucidated in biomedical experimentation models, which are influenced by ethics and by technical and methodological limitations.
In the footsteps of shamans
Ancient Chinese Wu healers could have derived the segmental (metameric) architecture of the body through a lengthy and disciplined observation and deduction process. Earlier doctors, in a shamanic context, used bloodletting to ‘placate ancestors and remove demons’40–42 but ultimately turned to punctures as an instrument. Through trial and error using a binomial characterisation of observed outcomes as a yang/yin method, Wu healers learned to pragmatically take advantage of innate on/off phenomena. Using PSS, they could elicit central nervous system (CNS) interneuron activation/inhibition ‘deciphered’ as yang/yin responses on suitable medullar segments.43 ,44 Chinese philosophers and scholars created the ‘Channels/Meridians theory’, with its inherent shortcomings, using a heuristic process and their sociohistorical backgrounds to explain such phenomena. The first part of the process could be referred to as the discovery of early ‘protoscience’, that is, a set of beliefs or theories that are aimed at establishing its legitimacy.45 ,46 In contrast, the second part corresponded with a complex metaphysical construct was a mixture of empirical observations and heuristic reasoning, which negatively impacts current acupuncture clinical research.18–21 47–53
Acupuncture research ignoring neurobiological aspects
The potential therapeutic effect of a needling protocol is derived from a neurobiological relationship, which would impact the results in acupuncture RCTs as shown in figure 2.
Figure 2A shows the dermatomes of the trunk with its meridians and points. The clinical indications for the points in any dermatome are similar, which suggests that such indications involve specific effects that are associated with the underlying visceral–somatic relationships of the acupuncture point as shown in figure 2B. From this perspective, needling any location on a dermatome could induce similar effects, which may explain why RCTs with control interventions such as needling outside of traditional points (sham acupuncture) yield negative outcomes. ‘Sham acupuncture’ can indeed induce specific effects and non-specific effects due to beliefs and expectations of the subject, which may lead to false-negative results.
Our results agree with longstanding and recent observations from acupuncture basic research studies and pioneering acupuncture RCTs and meta-analyses, which have consistently documented incongruities in important traditional beliefs.3–8 An unknown factor could be systematically associated with those conflicting results; therefore, we began our research to determine this factor.9 In a previous meta-analysis that was designed to study the success/failure rate of acupuncture RCTs and detect any significant outcomes, 90 RCTs with the following 2 types of simulated acupuncture models or ‘sham acupuncture’ were found: (1) ‘needling outside of but near classical points’, which was termed the ‘energetic placebo model’ (EPM); and (2) ‘random punctures far from classical points’, which was labelled the ‘metameric placebo model’ (MPM).10 Significant results were observed in 73.3% of the MPM group versus 33.3% of the EPM group (p<0.03). Additionally, ‘non-significant results but with remarkable symptomatic relief in more than 35% of subjects in both groups (false negatives) was observed in 80.0% of the EPM group of RCTs, against 20.0% in MPM (p<0.05)’.10 Therefore, control interventions using the energetic model of ‘sham acupuncture’ were as effective as real acupuncture, while those using the metameric (or segmental) model were less effective. Consequently, the control intervention can determine the failure of the acupuncture10 RCTs to demonstrate efficacy even when it is present, which could explain the high frequency of false negatives in acupuncture RCTs. However, in the trials in which the control intervention consisted of random needling on at least three or more segments away from the diseased zone (MPM), real acupuncture was clearly effective and was superior to ‘sham acupuncture’.10 Therefore, needling on a distant healthy area that is devoid of points would not alleviate the symptoms in a diseased zone.10 ,52 Curiously, the RCTs could not distinguish between active interventions and wrong inert interventions.
Our present and previous results suggest that most of RCTs and meta-analyses with conclusions that acupuncture performs as a placebo are wrong because such studies are typically based on the systematic assumption that sham acupuncture is an inert intervention.12–21 These findings, in conjunction with the ‘paradoxes’ that arise from the latest systematic research in this field,15–21 48–53 support the inaccuracy of several TCA assumptions.
Solving the puzzle
When the walls of a building begin to crack, it is foolish to hide the fissures with plaster and paint instead of examining its foundations to detect the eventual causes of collapse. Similarly, it is imperative to identify the contradictions and inconsistencies that have been observed in acupuncture clinical research. ‘Every object is identical to itself’ and ‘one tenet cannot be true and false simultaneously’.
With due respect for traditional methodology, modifications in the study sequence of acupuncture points, other than the order of their appearance in the meridians, have not been investigated. Nevertheless, adopting dermatomes as a connecting thread has demonstrated that any thoracic point, regardless of its meridian, could be stimulated to treat most of the visceral somatic symptoms of the pleura, the bronchia, the lungs, the pericardium, the heart, the oesophagus or the thymus because all of these organs share a somatic and autonomic innervation and an overlapping singular architecture.
This finding does not support the popular ‘meridian system’ or the assumption of stagnated energy flows to explain disease. Additionally, this finding is consistent with observations that reject other TCA postulates and supports several promising new approaches for contemporary acupuncture.55–60
Furthermore, the research of Professor Long-Xiang Huang of the Acupuncture Institute at the Academy of Traditional Chinese Medicine in Beijing does not support the meridian system. He claims that the theory of ‘Channels/Meridians’ was the cornerstone of classical acupuncture for centuries; however, this theory reflects the low level of medical knowledge of early doctors ‘who tentatively tried to explain the interrelatedness between the parts of the body surface and between the body surface and internal organs’.61 Additionally, Professor Huang remarked that ‘over several centuries, clinical evidence that did not fit into a traditional theory of Chinese Medicine was often suppressed to ensure continuity of the theories in a style that the Chinese call ‘cutting the foot to fit the shoe’’.61 He suggests that the channels/meridians theory is hindering further development in acupuncture in the 21st century. Our results are in agreement with these claims and weaken the claims of acupuncture point specificity, which have recently been dismissed by others.62–66 Additionally, our findings put into question some diagnostic and therapeutic features of acupuncture, whereas so-called ‘sham acupuncture’ should be excluded from future clinical studies because this intervention is not inert.
Do we need a new contemporary acupuncture model?
There are inconsistencies in the TCM acupuncture model that have been detected in early clinical and basic research and invalidate most of the postulates of this model. Punctures or other forms of PSS applied to dermatomes that share an innervation with a diseased zone could yield favourable effects.10 ,66 The importance of such effects are well established. Currently, ‘it seems clear that the peripheral and central nervous system can now be considered to be the most rational basis for defining meridians’.67 Furthermore, several studies have produced sufficient data that could support a Western contemporary vision of acupuncture when organised into a system. This vision would encompass an innovative approach based on contemporary medical science. This model would consider acupuncture to be an invaluable and useful method based on using PSS as an instrument and modern neurobiology as a guide for diagnosing and modulating the powerful self-regulating and self-healing mechanisms of the body. Stripped of its ancient attire, a vision of acupuncture that more closely resembles a scientific model could emerge: a model that is tentative, provisional, open to criticism, evolutionary and perfectible.68 ,69
Considering acupuncture as a tool to stimulate homeostasis–allostasis (neuromodulation for balancing affectivity, neuroimmunity, autonomic functions and antalgic processes and increasing the self-regenerative ability of the body) would have important practical implications. First, appropriate algorithms could be defined for body–brain–mind personalised acupuncture treatments for a broad spectrum of functional illnesses. Second, through translational science strategies, improvements could be made in the clinical profiles of neurosomatic and neurovisceral dysfunctions and in the physical and neurochemical diagnostic procedures designed for acupuncture. Similarly, the conception and execution of suitable control interventions could be redefined from a neurobiological perspective to advance clinical research.70 Additionally, it could eliminate the arduous and unproductive task of demonstrating obsolete metaphysical explanations of the unique neurobiological responses of the body to a clever form of PSS, which could be considered the amazing discovery of an early ‘protoneurobiology’ of health, disease and therapeutics that mankind owes to the sagacity of ancient Chinese doctors.
Furthermore, the diagnostic and therapeutic features of acupuncture could be confirmed in future clinical studies, whereas so-called ‘sham acupuncture’ should be excluded from future clinical studies because this intervention is not inert.
The acupuncture points grouped in each trunk dermatome exhibit similar indications irrespective of their meridian clinical properties. Therefore, in contrast to TCM postulates, point effects are derived from their underlying neural and somatic–visceral substrate; consequently, neurobiology emerges as a determinant factor for acupuncture action mechanisms. Therefore, our findings contribute in the following ways: (1) they explain the neurobiological basis of acupuncture and suggest that a neurobiology specialist should be included in future acupuncture research projects; (2) they clarify several confusing results from acupuncture RCTs and meta-analyses; (3) they support the reasonable exclusion of so-called ‘sham acupuncture’ that has been wrongly assumed to be an inert intervention and (4) they provide an ethical and rational basis for contemporary medical acupuncture.
We explored traditional and modern (Western) explanations for acupuncture by comparing the classical indications for each of 148 thoracic points with its neighbours on the same dermatome.
In all, 23% of the points had different indications, supporting the traditional meridian approach.
A total of 76% of the points had similar indications, supporting the Western neurological approach.
This finding has implications for acupuncture clinical practice and research.
The authors would like to express their deepest gratitude to Lic LA Nathalia Sánchez and to Dr Juan Torres from Universidad Central de Venezuela, for their invaluable support in obtaining, organising and processing the data; and to Dr Jesus E Conde PhD from the Instituto Venezolano de Investigaciones Científicas for his thorough revision and helpful support for the last version of this work.
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Files in this Data Supplement:
- Data supplement 1 - Online tables
Collaborators Nathalia Sánchez Lic LA, Juan Torres PhD, Universidad Central de Venezuela. Jesus Eloy Conde PhD, Instituto Venezolano de Investigaciones Científicas.
Contributors MS-A and AJL-B, participated in the whole process of conception of study and designing the research strategy and the study protocol. AJL-B, with the collaboration of Nathalia Sánchez, participated in the data collection and tabulation. MS-A and AJL-B performed the analysis and interpretation of data with the collaboration of Juan Torres. MS-A drafted the report. Both authors approved the final version of the manuscript. MS-A had responsibility for submitting the manuscript for publication.
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement A large table containing all the tabulated data (each dermatome table with its points set and their indications) has been uploaded as a web-only supplement.
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