Background: Acupuncture is still a controversial topic, as methodologic problems associated to its research impair scientific progress. Besides effective allocation of acupoints and double blinding, quantification of its effects is still a problem that has to be addressed. In particular, the effects of acupuncture need to be quantified more clearly for relieving pain and reducing inflammatory effects associated to Rheumatoid Arthritis (RA).
We aim to study the effects of acupuncture resorting to an algometry device specifically designed to assess the pressure tolerated by RA patients.
Methods/Design: A quasi-experimental nature design was developed. Fourteen RA patients with a Traditional Chinese Medicine (TCM) (Heidelberg Model) diagnosis of a so called pivotal or turning point syndrome, and meeting the criteria of the American College of Rheumatology, received three acupuncture treatments in one week with a standardized treatment.
A newly developed pressure algometry device, designed to assess the tolerance in hand pain in RA, was tested. We compared the outcome of clinical acupuncture, as measured by Pressure Algometry (PA) and Visual Analogue Scale (VAS).
Results: The patients tolerated higher pressure on the hands (p=0.001) as well as improved VAS scores along with the treatment (p=0.005). All 14 patients displayed improvements in PA, while 11 improved their VAS scores. Out of the remaining, two patients had their VAS score unaltered and one (who also displayed the smallest improvement in PA) worsened slightly.
Discussion: The findings of this study suggest that acupuncture effects in hand pain relief can be measured by the PA device. This opens the door to quantify the differences between the tolerated hand pressure before and after the acupuncture treatment to one specific TCM syndrome designed as turning point in a future double blinded acupuncture study on pain in RA patients.
Trial Registration Number: NCT02553005.
Rheumatoid Arthritis (RA) is a chronic systemic inflammatory autoimmune disease. Over 90% of patients with RA have involvement of the wrist and small joints of the hand, including the knuckles and the middle joints of the fingers involving destructive polyarthritis of the synovium. Pain is one of the major symptoms impacting an RA patient’s quality of life and leads in around 30% of the patients to limitations in daily life activities [1-3]. About 60 to 90% of patients with RA dissatisfied with conventional treatments side effects tend to use complementary and alternative medicine, including acupuncture [3-6].
Acupuncture in patients with RA can have the following effects: reduction of pro-inflammatory cytokines IL-1 and IL-6 and increase of cytokine inhibitors IL-4 and IL-10 ; induction of the expression of vasoactive intestinal peptide, an anti-inflammatory neuropeptide ; inhibition of the function of synovial mast cells (which are substantially involved in the initiation of inflammatory arthritis) and restoration of the hypothalamic-pituitary-adrenal axis .
Acupuncture generally stimulates the vegetative nervous system, which leads to the release of endorphins and other neurohumoral factors as well as to changes in the treatment of pain in the brain and spinal cord and to an increase in local microcirculation that helps to reduce edema [10,11].
Although RA is classified as a single disease in western medicine, in classical Chinese medicine it is believed to be the result of an invasion of the external pathogens (wind, cold, heat and damp), reactive heat with yin affection, qi and xue deficiency with stasis and phlegm, as well as of the deficiency patterns (liver and kidney yin or yang deficiency) [12-16]. Neurological and immunological RA phenomena can be explained by the cold (designated algor on the HM) aggression passing the skin (Biao) to reach the inner tissues of the body, while overcoming the six defense levels explained in detail by the Shang Han Lun theory called Algor Leadens Theory (ALT) by the Heidelberg Model (HM) of TCM in our previous paper . RA manifestations can be characterized in different syndromes according to this mathematical regulative model as a deviation from the regulated state .
Pain is inherently subjective and pain measurement in patients with RA relies primarily on self-reports or by simple palpation of the joints .
Although self reported pain intensity is important, it is a composition of the physiological and psychological features of the patient and their health problem that is further mediated by social aspects, which can make it difficult to interpret the responses .
Physicians often assume that inflammation is the main determinant factor of RA pain intensity. However more than one in ten RA patients that are shown to be in remission by the Disease Activity Score 28 (DAS28) still report clinically significant pain levels. The fact is that pain persists despite the absence of signs of inflammation .
The magnitude of symptoms may not necessarily correlate with the severity of the underlying disease and symptoms may persist even when disease exacerbations have apparently settled.
Pain and tenderness associated with the disease are not only present in directly affected joints but also in adjacent, apparently normal, tissues. These symptoms can occur spontaneously, can be evoked by gentle stimulation of the joint when it is moved within its normal working range or can be indicative of changes in their central pain modulation which then becomes a primary cause of pain, possibly outlasting the inflammatory activity [2,18].
In the classical Chinese medicine language, the occurrence of chronic pain in RA patients is explained as a dysfunctional pattern/sign or symptom of the neurovegetative system and is frequently accompanied by signs of yin deficiency symptoms, reactive heat and emotional imbalances such as anger, sadness or exhaustion .
Thus, objective pain measures are invaluable as they reflect different perspectives of the health condition. Therefore, measuring hand pain is an important component of clinical practice; its importance is evident in the frequency with which it drives healthcare utilization as well as its impact on quality of life .
Pressure Algometry (PA) has been used for the investigation of pain syndromes involving tenderness to assess different aspects of pain and tissue sensitivity to pressure in various rheumatic conditions . This instrument has demonstrated an outcome that physicians are able to use in both clinical as well as research settings to measure and quantify an individual’s pain experience by determining the pressure pain threshold of specific muscle and bone locations, the point at which a subject perceives pain upon the application of a pressure or force stimulus .
The PAs that are currently available rely on either a calibrated spring or an electronic force transducer. They are sensitive and accurate but expensive and fragile . In routine, clinical practice physicians need inexpensive, robust PA as a practical alternative for the assessment of tenderness in a wide range of patients. To observe quantitatively the differences between the tolerated hand pressure before and after the acupuncture treatment, we need an inexpensive self-assembly device.
In that way, we developed a specific PA, adapted to a computerized system, with the aim to objectify the variability effects of a standardized acupuncture treatment, by a physically measurable parameter. Therefore, we compared the outcome of clinical acupuncture, as measured by VAS and PA, in a sample of 14 RA patients and a specific vegetative functional state called turning point syndrome, to see whether the methods lead to correlating results.
|Sex (Male:Female)||2 (14.3%): 12 (85.7%)|
|Age, mean ± SD years||56.93 ± 3.23|
|Disease duration, mean ± SD years||14.36 ± 2.29|
|Body Mass Index||23.32 ± 0.67|
|Bone erosions (yes:no)||9 (64.3%):5 (35.7%)|
|Tender joints (0:2:6)||6 (42.9%):6 (42.9%):2 (14.3%)|
|Swollen Joints (0:2:4)||4 (28.6%):5 (35.7%):5 (35.7%)|
|Current medication||NSAIDs (yes:no)||6 (42.9%):8 (57.1%)|
|Biological agents (yes:no)||8 (57.1%):6 (42.9%)|
|DMARD’s (yes:no)||10 (71.4%):4 (28.6%)|
|Analgesics (yes:no)||10 (71.4%):4 (28.6%)|
|Pain (VAS, 0-10)||5.0 (5.0; 7.0)|
|Pain Sensation||Coldexposure||Relieves||4 (28.60%)|
|Hands temperature||Frozen||1 (7.10%)|
|Hands temperature||Frozen||1 (7.10%)|
|T0 (before 1st treatment)||5.0 (5.0; 7.0)||0.011||0.36 (0.32; 0.41)||0.003|
|T1 (after 1st treatment)||4.5 (3.0; 5.0)||0.52 (0.39; 0.56)|
|T2 (before 2nd treatment)||4.5 (3.0; 6.0)||0.015||0.45 (0.30; 0.56)||0.003|
|T3 (after 2nd treatment)||4.0 (3.0; 6.0)||0.59 (0.41; 0.64)|
|T4 (before 3rd treatment)||4.5 (3.0; 6.0)||0.019||0.43 (0.33; 0.45)||0.001|
|T5 (after 3rd treatment)||3.0 (2.0; 4.0)||0.56 (0.44; 0.68)|
|Change during treatment (T0-T5)||1.0 (1.0; 3.0)||0.005||0.17 (0.8; 0.36)||0.001|
This study was performed to evaluate the feasibility of a PA device, which was specifically designed to quantify pressure pain thresholds and possible effects of acupuncture . PA has been widely used in a variety of studies to measure the pressure pain stimulus response of subcutaneous muscles, as an abdominal examination value ; for the assessment of muscle hyperalgesia and a few number of studies used pressure algometer to assess the pressure pain thresholds in the temporomandibular joint and masticatory muscles [23-25].
In recent years, expensive and valid electronic pressure algometers have already been introduced on the market [22,26,27]. Additionally, several glove prototypes have been developed to assess the discomfort threshold level at 12 zones on the palmar surface of the hand . These devices were not used to test the pressure pain threshold by the hand grip in RA patients. We have no knowledge of existing PA devices that have been tested and validated to assess and precisely determine the process of determining the hand pressure that can be tolerated, as well as identify when the pain starts, all while being gripped by the RA patients themselves. Creating such a device was one of the objectives of the future RCT that we intend to develop .
The PA device that we developed was created specifically to assess the pain tolerance threshold of RA patients with hand pain whose features are related with a specific TCM diagnosis.
We tested the new PA device in a small group of 14 RA patients that fulfilled the research criteria’s. To reduce possible risks of mistakes, the examiner had intensive training to use the device and the same examiner assessed all of the participants.
The patients showed an increase in PA values and a decrease in VAS values (Table 2) during the progression of the treatment. The VAS values decreased significantly in most patients by the end of the third treatment. The change post treatment, shown in the last row of the table 2, is promising and we can see that each treatment resulted in an improvement of the clinical parameters (Table 3). The only patient that presented an increase in the VAS value was an older patient and only two male patients remained with the same VAS scores.
|Samples||Mn(theo)a × 10-4||Mn(NMR)b ×10-4||Mn(GPC)c ×10-4||Mw/Mnc||Rhd (nm)||?-potential (mV)|
Table 3: Pain values before and after acupuncture treatment. Data are presented as number (frequency).
Throughout the period of acupuncture treatments, no complications were found.
The increase of PA toleration can be correlated with the effect of the leopard spot technique at the chosen acupuncture points on the central vegetative nervous system and the induced mechanisms and is further supported by the decrease of the VAS-score. It is known that this technique increases local microcirculation by inducing a vegetative response and that it has the ability of alleviating pain .
Acupuncture positively influences areas of the brain that reduce sensitivity to pain, stress and inflammation, by promoting the release of vascular and immunomodulatory factors and by improving biomechanical functions .
Our results showed that exist a statistically significant association between the presence of nodules and an improvement in VAS, p=0.003 (fisher). Notably, all patients with nodules (11) improved and those without nodules (3) did not report any improvement. Recovering normal physiological functions induced by the nodules presence, bloodletting therapy can also accelerate the metabolism and stimulate the medullary hematopoiesis via neurohumoral regulation. This, therefore, improves microcirculation and vascular functions, stimulates blood regeneration and helps to rebuild homeostasis. By improving microcirculation, it can inhibit excessive inflammatory reactions and promote recovery .
We observed an increase in the pressure tolerated by the hand (objectively measurement) and a decrease of the self-reported pain, assessed by VAS score (subjectively measurement). Our pilot study suggests that using the PA developed we can observe and measure objectively the individual hand pressure toleration variability of patients, before and after the acupuncture treatment.
The data obtained with PA can be often quite variable. We recognize that such an instrument will have certain limitations as the non-applicability to other syndromes, not comparability with devices already created; we have no data enough to validate the specific device and also, the fact that it doesn’t have a patient controlled ‘stop’ button. Thus, we recognize that caution is required in the interpretation and reporting of clinical findings when using such device.
However, in the future, we intend to use the device to support and quantify the effects of the acupuncture in the treatment of RA patients with one specific TCM syndrome, and the use of subjective instruments can limit the interpretation of the results. Unfortunately, the devices existing in the market are not adjusted to assess the force tolerated by the hand grip of RA patients with a specific turning point syndrome.
On the basis of our methodology we keep the Traditional Chinese Acupuncture Practice characterized by a holistic approach to the management of the disease [19,32]. Based on the main characteristics, complaints and objective examinations of participants, a qualified and experienced TCM doctor established the functional diagnosis . In the present study, the clinical results show that the principle of point selection based on a specific TCM diagnosis including specific groups of signs and symptoms increases the effects of pain reduction and the toleration of hand pressure in RA patients.
A main purpose of our PA is to develop basic evidence that this device can be used as step towards objective research on acupuncture and, by objectifying pressure tolerance, as a measure of pain reduction, thus validating the effects of acupuncture.
In terms of sensory assessment, the detection of pressure pain thresholds may allow the development of mechanism-based therapeutic interventions that would specifically target the underlying pathophysiology . By using one objective assessment we can help to clarify and direct appropriate interventions in the treatment of RA patients.
Translation of these and other sensory findings into clear clinical benefits and improved outcomes for injured people is an area for future research. Future studies using pressure algometry are required to determine whether the PA is reliable when used on RA patients and also whether the algometry displays adequate inter-investigator reliability.
The findings of this study suggest that acupuncture effects in pain relief can be objectively assessed by the PA device developed. This opens the door to quantitative measurement of the pain improvement in future double blinded acupuncture studies on pain in RA patients.
Conventional pressure algometry is unsuitable for assessing the clinical therapeutic effectiveness on pain of RA patients with a turning point syndrome. We had needed to create a new PA device that could meet our future goals. The PA device tested has proven to be correctly adjusted to quantify the pressure pain threshold by the hand grip.
Based on the present data we are looking forward to using this instrument to do further investigation on the role of acupuncture in managing the symptoms of RA patients who are not willing to accept or react adversely to conventional pharmacological treatment, or who are seeking additional benefits from unconventional therapeutic combinations.
Concomitantly this was a preliminary test study preceding a longitudinal pragmatic design using acupuncture, sham acupuncture and no acupuncture treatment to assess the long-term effects of acupuncture on hand pain, functional deficits and health related quality of life in patients with RA.
S Seca designed the study and guided the experiment for the purpose of her ongoing PhD research. D Miranda collaborate as physicians and with the recruitment, the follow-up of patients enrolled into the study, the analysis and interpretation of data.
The engineers R Correia and J Reis developed the pressure algometry device. The statistical analysis was performed by M Patricio from the Laboratory of Biostatistics and Medical Informatics.
The authors gratefully acknowledge the support of Cara Nicholl, an American collaborator that reviewed the language.
Citation: Seca S, Miranda D, Patrício M, Correia R, Kirch S, et al. (2017) New Pressure Algometry Device for the Quantification of Acupuncture Induced Pain Relief. J Altern Complement Integr Med 3: 019.
Copyright: © 2017 Susana Seca, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.