The effect of acupuncture duration on analgesia and peripheral sensory thresholds

Duration of Electro-Dry Needling Does Not Change the Pain Response After Repeated Nociceptive Thermal Stimuli in Asymptomatic Individuals: A Randomized Intervention Study

Objective

To assess the effects of 5 different durations of electro-dry needling (EDN) on asymptomatic individuals' pain response after repeated noxious thermal stimuli.

Design

Randomized, non-controlled intervention trial.

Setting

University laboratory.

Participants

Asymptomatic participants (N=50) were recruited for the study and randomized into 5 groups. There were 33 women with an average age of 26.8 (±4.8) years. To participate in the study, individuals had to be between the ages of 18 and 40, free of any musculoskeletal injury which prevented participation of daily activities, and not pregnant or trying to become pregnant.

Interventions

Participants were randomly assigned to receive 5 different durations of EDN: 10, 15, 20, 25, and 30 minutes. To perform the EDN, 2 monofilament needles were inserted lateral to the lumbar spinous processes of L3 and L5 on the right. Needles were left in situ with electrical stimulation at a frequency of 2 Hz and an amplitude which resulted in a 3 to 6 out of 10 intensity pain rating by the participant.

Main Outcome Measures

The change in the magnitude of pain in response to repetitive heat-pulses before and after the EDN procedure.

Results

There was a significant reduction in the magnitude of pain in response across the groups after EDN (F(1,42)=94.12, P<.001, ƞp2=.691). However, the interaction between time and group was not significant (F(4,42)=1.019, P=.409, ƞp2=.088), indicating that no duration of EDN was superior to another in reducing temporal summation.

Conclusions

This study suggests that in asymptomatic individuals, performing EDN beyond 10 minutes does not provide any additional benefits in the reduction of the magnitude of pain in response to thermal nociceptive stimuli. Additional study in symptomatic populations is required for generalizability in clinical settings.

Using a consensus acupoints regimen to explore the relationship between acupuncture sensation and lumbar spinal postoperative analgesia: A retrospective analysis of prospective clinical cooperation

OBJECTIVE

This study evaluated the effectiveness of acupuncture treatment on postoperative pain in patients with degenerative lumbar spine disease, and explored the relationship between the postoperative analgesic effect of acupuncture and the sensation of acupuncture experienced by the patients.

METHODS

This retrospective study analyzed the medical records of 97 patients who had undergone an operation by the same surgeon due to degenerative lumbar disease. These patients were divided into acupuncture group (n = 32), patient-controlled analgesia (PCA) group (n = 27), and oral analgesia group (n = 38) according to the different postoperative analgesic methods. During their hospitalization, patients completed daily evaluations of their pain using a visual analogue scale (VAS), and injection times of supplemental meperidine were recorded. Also, the Chinese version of the Massachusetts General Hospital Acupuncture Sensation Scale (C-MASS) was used in the acupuncture group.

RESULTS

Each of the three treatment groups showed significant reductions in postoperative pain, as shown by reduced VAS scores. The acupuncture group, however, had less rebound pain (P < 0.05) than the other two groups. Both the acupuncture and PCA groups experienced acute analgesic effects that were superior to those in the oral analgesia group. In addition, the higher the C-MASS index on the second day after surgery, the lower the VAS score on the fourth day after surgery. There was also a significant difference in the "dull pain" in the acupuncture sensation.

CONCLUSION

The results demonstrated that acupuncture was beneficial for postoperative pain and discomfort after simple surgery for degenerative spinal disease. It is worth noting that there was a disproportionate relevance between the patient's acupuncture sensation and the improvement of pain VAS score.

Perioperative Analgesic Efficacy of Yamamoto New Scalp Acupuncture for Canine Mastectomy Combined with Ovariohysterectomy: a Randomized, Controlled Clinical Trial

Background

Yamamoto New Scalp Acupuncture (YNSA) is a therapy based on the stimulation of points on the scalp and applied to treat different states of pain.

Objectives

To investigate the analgesic efficacy of YNSA for dogs undergoing radical unilateral mastectomy with ovariohysterectomy.

Methods

Twenty-four dogs were randomly distributed into two treatments (n = 12, per group): bilateral stimulation of basic B, D, and E points (YNSA group) and no application of acupuncture (control group). All dogs were sedated with morphine; anesthesia was induced with propofol and maintained with isoflurane. Fentanyl was intraoperatively administered to control cardiovascular responses to surgical stimulation. Postoperative pain was assessed using an interactive visual analog scale (IVAS) and the short-form of the Glasgow Composite Pain Scale (CMPS-SF). Morphine was administered as rescue analgesia. Data were analyzed using t-tests, Fisher's exact test, Mann-Whitney U test, and Friedman test (p < 0.05).

Results

Intraoperatively, the number of dogs requiring supplemental analgesic and the number of doses of fentanyl were lower in the YNSA group than in the control group (p = 0.027-0.034). The IVAS pain scores recorded from 0.5 h to 1 h post-extubation in the YNSA group were lower than those in the control group (p = 0.021-0.023). Postoperative rescue analgesia and CMPS-SF pain scores did not differ between the groups.

Conclusion

YNSA decreases intraoperative fentanyl requirements and provides minimal postoperative analgesic benefits to dogs undergoing unilateral mastectomy with ovariohysterectomy.

Spinal manipulation and perineural electrical dry needling in patients with cervicogenic headache: a multicenter randomized clinical trial

BACKGROUND CONTEXT

Spinal manipulation, spinal mobilization, and exercise are commonly used in individuals with cervicogenic headache (CH). Dry needling is being increasingly used in the management of CH. However, questions remain about the effectiveness of these therapies and how they compare to each other.

PURPOSE

The present study aims to compare the combined effects of spinal manipulation and dry needling with spinal mobilization and exercise on pain and disability in individuals with CH.

STUDY DESIGN/SETTING

Randomized, multicenter, parallel-group trial.

PATIENT SAMPLE

One hundred forty-two patients (n=142) with CH from 13 outpatient clinics in 10 different states were recruited over a 36-month period.

OUTCOME MEASURES

The primary outcome was headache intensity as measured by the Numeric Pain Rating Scale. Secondary outcomes included headache frequency and duration, disability (Neck Disability Index), medication intake, and the Global Rating of Change (GROC). Follow-up assessments were taken at 1 week, 4 weeks, and 3 months.

METHODS

Patients were randomized to receive upper cervical and upper thoracic spinal manipulation plus electrical dry needling (n=74) or upper cervical and upper thoracic spinal mobilization and exercise (n=68). In addition, the mobilization group also received a program of craniocervical and peri-scapular resistance exercises; whereas, the spinal manipulation group also received up to eight sessions of perineural electrical dry needling. The treatment period for both groups was 4 weeks. The trial was prospectively registered at ClinicalTrials.gov (NCT02373605). Drs Dunning, Butts and Young are faculty within the AAMT Fellowship and teach postgraduate courses in spinal manipulation, spinal mobilization, dry needling, exercise and differential diagnosis. The other authors declare no conflicts of interest. None of the authors received any funding for this study.

RESULTS

The 2 × 4 analysis of covariance revealed that individuals with CH who received thrust spinal manipulation and electrical dry needling experienced significantly greater reductions in headache intensity (F=23.464; p<.001), headache frequency (F=13.407; p<.001), and disability (F=10.702; p<.001) than those who received nonthrust mobilization and exercise at a 3-month follow-up. Individuals in the spinal manipulation and electrical dry needling group also experienced shorter duration of headaches (p<.001) at 3 months. Based on the cutoff score of ≥+5 on the GROC, significantly (X²=54.840; p<.001) more patients (n=57, 77%) within the spinal manipulation and electrical dry needling group achieved a successful outcome compared to the mobilization and exercise group (n=10, 15%) at 3-month follow-up. Between-groups effect sizes were large (0.94<standardized mean score difference<1.25) in all outcomes in favor of the spinal manipulation and electrical dry needling group at 3 months. In addition, significantly (X²=29.889; p<.001) more patients in the spinal manipulation and electrical dry needling group (n=49, 66%) completely stopped taking medication for their pain compared to the spinal mobilization and exercise group (n=14, 21%) at 3 months.

CONCLUSION

Upper cervical and upper thoracic high-velocity low-amplitude thrust spinal manipulation and electrical dry needling were shown to be more effective than nonthrust mobilization and exercise in patients with CH, and the effects were maintained at 3 months.

Dry needling strategies for musculoskeletal conditions: Do the number of needles and needle retention time matter? A narrative literature review

Acupuncture and dry needling are both minimally invasive procedures that use thin, filiform needles without injectate for the management of a variety of neuromusculoskeletal pain conditions. While the theoretical constructs underlying the use of acupuncture and dry needling are unique, both appear to have the ability to elicit biochemical, biomechanical, endocrinological and neurovascular changes associated with reductions in pain and disability. However, optimal treatment dosage has yet to be determined, and there is a lack of consistency in the literature on the number of needles that should be inserted and the needle retention time. Therefore, the purpose of this narrative review is to further explore the importance of these two variables. While trigger point dry needling advocates single needle insertions via repetitive, quick in-and-out pistoning, most acupuncture and dry needling clinical trials have incorporated multiple needles for five to 40 min. Notably and to date, using a single needle to repeatedly prick trigger points one at a time with fast-in and fast-out pistoning maneuvers has not yet been shown to produce significant and clinically meaningful long term improvements in pain and disability in a wide array of musculoskeletal conditions. Insertion of multiple needles for typically 20-30 min durations has been shown to produce larger treatment effect sizes and longer-lasting outcomes than brief, single-needle strategies. Moreover, the number of needles and needle retention time are two variables associated with treatment dosage and must be carefully matched with specific musculoskeletal conditions and the patient's goals.

Local and Systemic Analgesic Effects of Nerve-Specific Acupuncture in Healthy Adults, Measured by Quantitative Sensory Testing

OBJECTIVE

This study aims to assess whether acupuncture analgesia's effects are local or systemic and whether there is a dose response for these effects.

METHODS

Twenty-eight healthy volunteers aged 18-45 were randomized to two doses of acupuncture using points closely associated with peripheral nerves in the legs. The lower-dose group involved acupoints overlying the deep peroneal nerve (DP), and the higher-dose involved acupoints overlying the deep peroneal and posterior tibial nerves (DPTN). Baseline and acupuncture quantitative sensory testing (QST) assessments were obtained locally in the calf and great toe and systemically in the hand. Results were analyzed using factorial repeated-measures analysis of variance for each of the QST variables-cold detection threshold (CDT), vibration detection threshold (VDT), heat pain threshold (HP0.5), and heat pain perception of 5/10 (HP5.0). Location (leg/hand) and time (baseline/acupuncture) were within-subject factors. Intervention (DP/DPTN) was a between-subject factor.

RESULTS

CDT was increased in the calf (P < 0.001) and in the hand (P < 0.001). VDT was increased in the toe (P < 0.001) but not in the hand. HP0.5 was increased in the calf (P < 0.001) and in the hand (P < 0.001). HP5.0 was increased in the calf (P = 0.002) and in the hand (P < 0.001), with the local effect being significantly greater than the systemic (P = 0.004). In all of the above QST modalities, there was no difference between the low-dose (DP) and high-dose (DPTN) acupuncture groups.

CONCLUSIONS

Acupuncture caused comparable local and systemic analgesic effects in cold detection and heat pain perception and only local effects in vibration perception. There was no clear acupuncture dose response to these effects.

Interaction of energetic points, tendinomuscular meridian and 5 elements in the treatment of osteoarthritis of the knee in patients over 45 years old: a randomized controlled trial

INTRODUCTION

Acupuncture had a different approaches since its beginnings. Using traditional energetic points with an interaction of 5 elements and meridian theories with manual diagnosis of tender points has been proposed. This procedure can be an effective treatment in musculoskeletal disease but its development is short.

OBJECTIVES

To evaluate the efficacy of energetic points of tendinomuscular meridian in the treatment of pain, quality of life and function of the knee.

DESIGN

Randomized controlled trial, non standardized and double blind. Inclusions criteria were: being over 45 years, having had pain for more than 3 months, level II o greater in Kellgren-Lawrence and suffering morning stiffness. Exclusion criteria were artoplasty, corticosteroids and rehabilitation, arthropaties, autoinmune diseases and neuropathic pain.

RESULTS

Intervention group had significant improvement in average pain in the last 15 days at end of treatment (p<0.04) and quality of life at the end of follow-up (p<0.015). Other measurements no show significant differences between groups.

CONCLUSIONS

Energetic points of tendinomuscular meridian and the 5 elements related are equal or better than local acupuncture in the treatment of pain, quality of life and function in osteoarthritis of the knee. However, it is necessary to have more research with more tracing and poblation to improve the quality of the results.

Acupuncture for Cancer Pain and Symptom Management in a Palliative Medicine Clinic

OBJECTIVE:

Studies suggest acupuncture improves cancer-related symptoms; however, it is unclear whether patient characteristics predict pain response. This study determined acupuncture's effect on cancer-related pain and identified variables associated with pain response.

METHODS:

A retrospective chart review included adult patients with cancer referred to palliative medicine and received acupuncture for pain management. Paired t tests compared differences in pain scores from pre- to postacupuncture. Clinically meaningful pain improvement was defined as ≥2-point reduction in pain score. Logistic regression was used to evaluate associations between patient characteristics and pain improvement.

RESULTS:

One hundred seventy acupuncture treatments from 68 individual patients were studied. Significant reductions in mean pain scores were observed after the first treatment (-1.9 ± 1.8; P < .001) and across all treatments (-1.7 ± 1.9; P < .001). Multivariable analysis demonstrated clinically meaningful pain improvement with higher baseline pain scores (odds ratio [OR]: 1.79, 95% confidence interval [CI]: 1.44-2.22; P < .001) and stage III/IV disease (OR: 3.23, 95% CI: 1.11-9.40; P < .001). There were significant improvements in anxiety, depression, drowsiness, dyspnea, fatigue, nausea, and well-being after the first treatment and across all treatments ( P < .001).

CONCLUSIONS:

Acupuncture improved cancer-related pain and other symptoms. Those with higher baseline pain scores and advanced disease were more likely to achieve significant pain reduction. Improved depression and fatigue were closely related to pain reduction. Further studies are needed to confirm pain response variables, establish durability, and develop a personalized approach to acupuncture.

Acupuncture for neuropathic pain in adults

BACKGROUND

Neuropathic pain may be caused by nerve damage, and is often followed by changes to the central nervous system. Uncertainty remains regarding the effectiveness and safety of acupuncture treatments for neuropathic pain, despite a number of clinical trials being undertaken.

OBJECTIVES

To assess the analgesic efficacy and adverse events of acupuncture treatments for chronic neuropathic pain in adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, four Chinese databases, ClinicalTrials.gov and World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) on 14 February 2017. We also cross checked the reference lists of included studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) with treatment duration of eight weeks or longer comparing acupuncture (either given alone or in combination with other therapies) with sham acupuncture, other active therapies, or treatment as usual, for neuropathic pain in adults. We searched for studies of acupuncture based on needle insertion and stimulation of somatic tissues for therapeutic purposes, and we excluded other methods of stimulating acupuncture points without needle insertion. We searched for studies of manual acupuncture, electroacupuncture or other acupuncture techniques used in clinical practice (such as warm needling, fire needling, etc).

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. The primary outcomes were pain intensity and pain relief. The secondary outcomes were any pain-related outcome indicating some improvement, withdrawals, participants experiencing any adverse event, serious adverse events and quality of life. For dichotomous outcomes, we calculated risk ratio (RR) with 95% confidence intervals (CI), and for continuous outcomes we calculated the mean difference (MD) with 95% CI. We also calculated number needed to treat for an additional beneficial outcome (NNTB) where possible. We combined all data using a random-effects model and assessed the quality of evidence using GRADE to generate 'Summary of findings' tables.

MAIN RESULTS

We included six studies involving 462 participants with chronic peripheral neuropathic pain (442 completers (251 male), mean ages 52 to 63 years). The included studies recruited 403 participants from China and 59 from the UK. Most studies included a small sample size (fewer than 50 participants per treatment arm) and all studies were at high risk of bias for blinding of participants and personnel. Most studies had unclear risk of bias for sequence generation (four out of six studies), allocation concealment (five out of six) and selective reporting (all included studies). All studies investigated manual acupuncture, and we did not identify any study comparing acupuncture with treatment as usual, nor any study investigating other acupuncture techniques (such as electroacupuncture, warm needling, fire needling).One study compared acupuncture with sham acupuncture. We are uncertain if there is any difference between the two interventions on reducing pain intensity (n = 45; MD -0.4, 95% CI -1.83 to 1.03, very low-quality evidence), and neither group achieved 'no worse than mild pain' (visual analogue scale (VAS, 0-10) average score was 5.8 and 6.2 respectively in the acupuncture and sham acupuncture groups, where 0 = no pain). There was limited data on quality of life, which showed no clear difference between groups. Evidence was not available on pain relief, adverse events or other pre-defined secondary outcomes for this comparison.Three studies compared acupuncture alone versus other therapies (mecobalamin combined with nimodipine, and inositol). Acupuncture may reduce the risk of 'no clinical response' to pain than other therapies (n = 209; RR 0.25, 95% CI 0.12 to 0.51), however, evidence was not available for pain intensity, pain relief, adverse events or any of the other secondary outcomes.Two studies compared acupuncture combined with other active therapies (mecobalamin, and Xiaoke bitong capsule) versus other active therapies used alone. We found that the acupuncture combination group had a lower VAS score for pain intensity (n = 104; MD -1.02, 95% CI -1.09 to -0.95) and improved quality of life (n = 104; MD -2.19, 95% CI -2.39 to -1.99), than those receiving other therapy alone. However, the average VAS score of the acupuncture and control groups was 3.23 and 4.25 respectively, indicating neither group achieved 'no worse than mild pain'. Furthermore, this evidence was from a single study with high risk of bias and a very small sample size. There was no evidence on pain relief and we identified no clear differences between groups on other parameters, including 'no clinical response' to pain and withdrawals. There was no evidence on adverse events.The overall quality of evidence is very low due to study limitations (high risk of performance, detection, and attrition bias, and high risk of bias confounded by small study size) or imprecision. We have limited confidence in the effect estimate and the true effect is likely to be substantially different from the estimated effect.

AUTHORS' CONCLUSIONS

Due to the limited data available, there is insufficient evidence to support or refute the use of acupuncture for neuropathic pain in general, or for any specific neuropathic pain condition when compared with sham acupuncture or other active therapies. Five studies are still ongoing and seven studies are awaiting classification due to the unclear treatment duration, and the results of these studies may influence the current findings.

Interaction of acupuncture treatment and manipulation laterality modulated by the default mode network

Appropriate selection of ipsilateral or contralateral electroacupuncture (corresponding to the pain site) plays an important role in reaching its better curative effect; however, the involving brain mechanism still remains unclear. Compared with the heat pain model generally established in previous study, capsaicin pain model induces reversible cutaneous allodynia and is proved to be better simulating aspects of clinical nociceptive and neuropathic pain. In the current study, 24 subjects were randomly divided into two groups with a 2 × 2 factorial design: laterality (ipsi- or contralateral side, inter-subject) × treatment with counter-balanced at an interval of one week (verum and placebo electroacupuncture, within-subject). We observed subjective pain intensity and brain activations changes induced by capsaicin allodynia pain stimuli before and after electroacupuncture treatment at acupoint LI4 for 30 min. Analysis of variance results indicated that ipsilateral electroacupuncture treatment produced significant pain relief and wide brain signal suppressions in pain-related brain areas compared with contralateral electroacupuncture. We also found that verum electroacupuncture at either ipsi- or contralateral side to the pain site exhibited comparable significant magnitudes of analgesic effect. By contrast, placebo electroacupuncture elicited significant pain reductions only on the ipsilateral rather than contralateral side. It was inferred that placebo analgesia maybe attenuated on the region of the body (opposite to pain site) where attention was less focused, suggesting that analgesic effect of placebo electroacupuncture mainly rely on the motivation of its spatial-specific placebo responses via attention mechanism. This inference can be further supported by the evidence that the significant interaction effect of manipulation laterality and treatment was exclusively located within the default mode network, including the bilateral superior parietal lobule, inferior parietal lobule, precuneus, and left posterior cingulate cortex. It is also proved that disruptions of the default mode network may account for the cognitive and behavioral impairments in chronic pain patients. Our findings further suggested that default mode network participates in the modulation of spatial-oriented attention on placebo analgesia as a mechanism underlying the degree to which treatment side corresponding to the pain.

Diminished supraspinal pain modulation in patients with mild traumatic brain injury

Background

Chronic pain conditions are highly prevalent in patients with mild traumatic brain injury. Supraspinal diffuse axonal injury is known to dissociate brain functional connectivity in these patients. The effect of this dissociated state on supraspinal pain network is largely unknown. A functional magnetic resonance imaging study was conducted to compare the supraspinal pain network in patients with mild traumatic brain injury to the gender and age-matched healthy controls with the hypothesis that the functional connectivities of the medial prefrontal cortices, a supraspinal pain modulatory region to other pain-related sensory discriminatory and affective regions in the mild traumatic brain injury subjects are significantly reduced in comparison to healthy controls.

Results

The mild traumatic brain injury group (N = 15) demonstrated significantly (P < 0.01, cluster threshold > 150 voxels) less activities in the thalamus, pons, anterior cingulate cortex, insula, dorsolateral prefrontal cortex, and medial prefrontal cortices than the healthy control group (N = 15). Granger Causality Analyses (GCA) indicated while the left medial prefrontal cortices of the healthy control group cast a noticeable degree of outward (to affect) causality inference to multiple pain processing related regions, this outward inference pattern was not observed in the mild traumatic brain injury group. On the other hand, only patients’ bilateral anterior cingulate cortex received multiple inward (to be affected) causality inferences from regions including the primary and secondary somatosensory cortices and the inferior parietal lobe. Resting state functional connectivity analyses indicated that the medial prefrontal cortices of the mild traumatic brain injury group demonstrated a significantly (P < 0.01, F = 3.6, cluster size > 150 voxels) higher degree of functional connectivity to the inferior parietal lobe, premotor and secondary somatosensory cortex than the controls. Conversely, the anterior cingulate cortex of the healthy group demonstrated significantly (P < 0.01, F = 3.84, cluster size > 150 voxels) less degree of functional connectivities to the inferior parietal lobe and secondary somatosensory cortex than their mild traumatic brain injury counterparts.

Conclusions

In short, the current study demonstrates that patients with mild traumatic brain injury and headaches appear to have an altered state of supraspinal modulatory and affective functions related to pain perception.

Acupuncture-induced changes of pressure pain threshold are mediated by segmental inhibition--a randomized controlled trial

Our aim was to distinguish between spinal and supraspinal mechanisms in the intact nervous system by comparing homosegmental and heterosegmental effects of electroacupuncture (EA) and manual acupuncture (MA) on sensory perception in healthy volunteers by means of quantitative sensory testing. Seventy-two healthy volunteers were randomly assigned to receive either MA or EA at SP 6, SP 9, GB 39, and ST 36 at the left leg or relaxed for 30 minutes (control group [CG]). Blinded examiners assessed 13 sensory modalities (thermal and mechanical detection and pain thresholds) at the upper arms and lower legs before and after intervention by means of a standardized quantitative sensory testing battery. Change scores of all 13 sensory thresholds were compared between groups. The main outcome measure was the change score of the pressure pain threshold (PPT). There were no baseline differences between groups. Pressure pain threshold change scores at the lower left leg, in the same segment as the needling site, differed significantly (P = 0.008) between the EA (median: 103.01 kPa) and CG groups (median: 0.00 kPa) but not between the MA (median: 0.00 kPa) and CG groups. No further significant change score differences were found between one of the acupuncture groups and the CG. The PPT can be changed by EA. The PPT increase was confined to the segment of needling, which indicates that it is mainly mediated by segmental inhibition in the spinal cord. This underscores the importance of segmental needling and electrical stimulation in clinical practice.

Is sham acupuncture as effective as traditional Chinese acupuncture? It's too early to say

Many clinical trials and experimental studies claim that sham acupuncture is as effective as traditional Chinese acupuncture. However, these studies have no standard sham acupuncture control and many other factors can affect the clinical effect. These factors include needle retention time, treatment frequency, and the total number of treatments needed for satisfactory results, and all can change the clinical effect. The majority of existing acupuncture treatment studies do not consider these factors and lack standard dosage criteria. Therefore, it is still too early to conclude that sham acupuncture is as effective as traditional Chinese acupuncture. This article investigates the factors that influence the curative effect of acupuncture as to help set a standard for acupuncture studies in the future.

Effect of low frequency transcutaneous magnetic stimulation on sensory and motor transmission

Peripheral nerve injury diminishes fast conducting large myelinated afferent fibers transmission but enhances smaller pain transmitting fibers firing. This aberrant afferent neuronal behavior contributes to development of chronic post-traumatic peripheral neuropathic pain (PTP-NP). Non-invasive dynamic magnetic flux stimulation has been implicated in treating PTP-NP, a condition currently not adequately addressed by other therapies including transcutaneous electrical nerve stimulation (TENS). The current study assessed the effect of low frequency transcutaneous magnetic stimulation (LFTMS) on peripheral sensory thresholds, nerve conduction properties, and TENS induced fast afferent slowing effect as measured by motor and sensory conduction studies in the ulnar nerve. Results indicated sham LFTMS with TENS (Sham + TENS) significantly (P = 0.02 and 0.007, respectively) reduces sensory conduction velocity (CV) and increases sensory onset latency (OL), and motor peak latency (PL) whereas, real LFTMS with TENS (Real + TENS) reverses effects of TENS on sensory CV and OL, and significantly (P = 0.036) increases the sensory PL. LFTMS alone significantly (P < 0.05) elevates sensory PL and onset-to-peak latency. LFTMS appears to reverse TENS slowing effect on fast conducting fibers and casts a selective peripheral modulatory effect on slow conducting pain afferent fibers.

Effects of acupuncture on sensory perception: a systematic review and meta-analysis

BACKGROUND

The effect of acupuncture on sensory perception has never been systematically reviewed; although, studies on acupuncture mechanisms are frequently based on the idea that changes in sensory thresholds reflect its effect on the nervous system.

METHODS

Pubmed, EMBASE and Scopus were screened for studies investigating the effect of acupuncture on thermal or mechanical detection or pain thresholds in humans published in English or German. A meta-analysis of high quality studies was performed.

RESULTS

Out of 3007 identified articles 85 were included. Sixty five studies showed that acupuncture affects at least one sensory threshold. Most studies assessed the pressure pain threshold of which 80% reported an increase after acupuncture. Significant short- and long-term effects on the pressure pain threshold in pain patients were revealed by two meta-analyses including four and two high quality studies, respectively. In over 60% of studies, acupuncture reduced sensitivity to noxious thermal stimuli, but measuring methods might influence results. Few but consistent data indicate that acupuncture reduces pin-prick like pain but not mechanical detection. Results on thermal detection are heterogeneous. Sensory threshold changes were equally frequent reported after manual acupuncture as after electroacupuncture. Among 48 sham-controlled studies, 25 showed stronger effects on sensory thresholds through verum than through sham acupuncture, but in 9 studies significant threshold changes were also observed after sham acupuncture. Overall, there is a lack of high quality acupuncture studies applying comprehensive assessments of sensory perception.

CONCLUSIONS

Our findings indicate that acupuncture affects sensory perception. Results are most compelling for the pressure pain threshold, especially in pain conditions associated with tenderness. Sham acupuncture can also cause such effects. Future studies should incorporate comprehensive, standardized assessments of sensory profiles in order to fully characterize its effect on sensory perception and to explore the predictive value of sensory profiles for the effectiveness of acupuncture.

The effect of acupuncture needle combination on central pain processing--an fMRI study

Background

Empirical acupuncture treatment paradigm for acute pain utilizing Tendinomuscular Meridians (TMM) calls for the stimulation of Ting Points (TPs) and Gathering point(GP). This study aims to compare the supraspinal neuronal mechanisms associated with both TPs and GP needling (EA3), and TPs needling alone (EA2) with fMRI.

Results

A significant (P < 0.01) difference between pre-scan (heat Pain) HP, and post-EA HP VAS scores in both paradigms was noted (n = 11). The post-EA HP VAS score was significantly (P < 0.05) lower with EA3 comparing to EA2 Within-group random effect analysis indicated that EA3+HP>EA3 (condition EA3+HP subtracted by condition EA3) appeared to exert a significant degree of activity suppression in the affective supraspinal regions including the IPL, anterior cingulate cortex (ACC) and the insular cortex (IN). This level of suppression was not observed in the EA2+HP>EA2 (condition EA2+HP subtracted by condition EA2) within-group random effect analysis Between-group random effect analysis indicated that EA3 induced a significantly (P < 0.01, cluster size threshold 150) higher degree of deactivation than EA2 in several pain related supraspinal regions including the right prefrontal cortex, rostral anterior cingulate (rACC), medial cingulate cortex, left inferior frontal lobe and posterior cerebellum. The 2-factor ANOVA in those regions indicated both rACC and posterior cerebellum had a significant (P < 0.01) needle effect, and the right prefrontal area showed a significant (P < 0.01) HP effect. However, a significant interaction between the two factors was only found in the right prefrontal lobe. Granger causality analysis showed EA3 induced a much higher degree of inference among HP related supraspinal somatosensory, affective and modulatory components than EA2. Deactivation pattern at the medullary-pontine area casted a direct inference on the deactivation pattern of secondary somatosensory cortices which also affected the deactivation of the IN.

Conclusions

While both EA2 and EA3 induced a significant degree of deactivation in the human brain regions related to pain processing, the addition of GP stimulation further exerts an inhibitory effect on the ascending spinoreticular pain pathway. Therefore, different needling position as mandated in different empirical acupuncture treatment paradigms may play a different role in modulating pain related neuronal functions.

Supraspinal characterization of the thermal grill illusion with fMRI

Background

Simultaneous presentation of non-noxious warm (40°C) and cold (20°C) stimuli in an interlacing fashion results in a transient hot burning noxious sensation (matched at 46°C) known as the thermal grill (TG) illusion. Functional magnetic resonance imaging and psychophysical assessments were utilized to compare the supraspinal events related to the spatial summation effect of three TG presentations: 20°C/20°C (G2020), 20°C/40°C (G2040) and 40°C/40°C (G4040) with corresponding matched thermode stimuli: 20°C (P20), 46°C (P46) and 40°C (P40) and hot pain (HP) stimuli.

Results

For G2040, the hot burning sensation was only noted during the initial off-line assessment. In comparison to P40, G4040 resulted in an equally enhanced response from all supraspinal regions associated with both pain sensory/discriminatory and noxious modulatory response. In comparison to P20, G2020 presentation resulted in a much earlier diminished/sedative response leading to a statistically significantly (P < 0.01) higher degree of deactivation in modulatory supraspinal areas activated by G4040. Granger Causality Analysis showed that while thalamic activation in HP may cast activation inference in all hot pain related somatosensory, affective and modulatory areas, similar activation in G2040 and G2020 resulted in deactivation inference in the corresponding areas.

Conclusions

In short, the transient TG sensation is caused by a dissociated state derived from non-noxious warm and cold spatial summation interaction. The observed central dissociated state may share some parallels in certain chronic neuropathic pain states.

One Medicine, One Acupuncture

Simple Summary

“One Acupuncture”, modeled after “One Medicine”, embodies a system of translational acupuncture built upon science and hypothesis-driven research. Forging a synthesis between human and veterinary acupuncture requires consistency in point location across species so that meaningful comparisons can be made. The human acupuncture network provides a template of well-studied neurovascular sites that have changed little over the years, in comparison to their veterinary counterparts. This paper identifies disparities that remain. Reconciling inconsistencies will bolster the ability for researchers and clinicians to better understand and interpret findings from acupuncture studies on various species so that more can benefit from these insights.

Abstract

“One Acupuncture”, like “One Medicine”, has the potential to improve research quality and clinical outcomes. However, while human acupuncture point locations have remained largely consistent over time, the veterinary versions remain imprecise and variable. Establishing anatomical criteria for veterinary acupuncture atlases in keeping with the human template will create congruence across species, benefiting both research and practice. Anatomic criteria for points based on objectively verifiable structures will facilitate translational research. Functionally comparative innervation, in particular, should be similar between species, as the nerves initiate and mediate physiologic changes that result from point stimulation. If researchers choose points that activate different nerves in one species than in another, unpredictable outcomes may occur. Variability in point placement will impede progress and hamper the ability of researchers and clinicians to make meaningful comparisons across species. This paper reveals incongruities that remain between human and veterinary acupuncture points, illustrating the need to analyze anatomical characteristics of each point to assure accuracy in selecting transpositional acupuncture locations.

The analgesic effect of electroacupuncture on acute thermal pain perception--a central neural correlate study with fMRI

BACKGROUND

Electrical acupuncture (EA) has been utilized in acute pain management. However, the neuronal mechanisms that lead to the analgesic effect are still not well defined. The current study assessed the intensity [optimal EA (OI-EA) vs. minimal EA (MI-EA)] effect of non-noxious EA on supraspinal regions related to noxious heat pain (HP) stimulation utilizing an EA treatment protocol for acute pain and functional magnetic resonance imaging (fMRI) with correlation in behavioral changes. Subjects underwent five fMRI scanning paradigms: one with heat pain (HP), two with OI-EA and MI-EA, and two with OI-EA and HP, and MI-EA and HP.

RESULTS

While HP resulted in activations (excitatory effect) in supraspinal areas known for pain processing and perception, EA paradigms primarily resulted in deactivations (suppressive effect) in most of these corresponding areas. In addition, OI-EA resulted in a more robust supraspinal sedative effect in comparison to MI-EA. As a result, OI-EA is more effective than MI-EA in suppressing the excitatory effect of HP in supraspinal areas related to both pain processing and perception.

CONCLUSION

Intensities of EA plays an important role in modulating central pain perception.

The effect of brief electrical and manual acupuncture stimulation on mechanical experimental pain

OBJECTIVE

Although manual and electrical stimulation are frequently used in acupuncture analgesia, studies comparing both stimulation modalities are contradictory. This blinded, placebo-controlled cross-over study investigates effects of brief manual and electrical acupuncture stimulation on pressure pain detection thresholds (PPDT) compared with nonpenetrating sham acupuncture (NPSA).

INTERVENTIONS

Forty-five healthy volunteers received electrically and manually stimulated acupuncture and NPSA at large intestine 4 and 11 in randomized order. PPDT was assessed using pressure algometry at the second toe before; during; and 0, 2, and 5 minutes after each intervention. Stimulus intensity during stimulation was rated on a 0-10 numeric rating scale (NRS).

RESULTS

PPDT rose from 316 kPa (standard deviation [SD] 149) to 398 kPa (SD 157) and 405 kPa (SD 184) immediately after acupuncture with manual and electrical stimulation, respectively, and to 380 kPa (SD 175) and 367 kPa (SD 168) after NPSA with simulated manual and electrical stimulation, respectively. During the intervention, electroacupuncture produced a higher PPDT increase than any other procedure (P<0.001). Immediately after, both acupuncture procedures were significantly more effective than NPSA (P<0.001) but did not mutually differ (P=0.082). NRS ratings differed significantly: manual acupuncture 4.1, electroacupuncture 2.7, manual NPSA 2.5, electro-NPSA 1.2 (P<0.001 except for electroacupuncture vs manual NPSA, P=0.271).

CONCLUSION

Electroacupuncture produced higher PPDT elevation than manual acupuncture, and acupuncture in general showed significantly greater analgesic effect than NPSA. These effects seem to be short lasting (<5 minutes) in the context of only brief acupuncture. The superiority of acupuncture to NPSA provides further evidence for acupuncture-specific analgesic effects.

Acupuncture effect on thermal tolerance and electrical pain threshold: a randomised controlled trial

OBJECTIVE

The aim of this study was to test whether acupuncture could modify the threshold of tolerance to thermal and electrical stimuli.

METHODS

A randomised placebo-controlled single-blind trial was conducted in 36 healthy volunteers randomly distributed to control (no treatment), conventional acupuncture and sham acupuncture groups. The subjects were blind to the group allocation. The authors measured before and after treatment the pain threshold with the Painmatcher (Cefar Medical AB, Lund, Sweden) and the cold tolerance with the cold pressor test, together with the Visual Analogue Scale pain score.

RESULTS

Electrical stimulation threshold and cold pressor tolerance both increased significantly in the control and the true acupuncture groups, but not the sham group. The changes in the true acupuncture group were highly statistically significant and amounted to 24% (pain threshold) and 44% (cold tolerance) increases in threshold. The changes in the true group were significantly greater than the control group but not significantly different from the sham group. The changes in the sham and control groups were not significantly different from each other.

CONCLUSION

Acupuncture at true, appropriate points was more effective than no intervention in raising pain threshold and tolerance in volunteers, and acupuncture at inappropriate points had an intermediate effect which was not significantly different from either. Thus acupuncture analgesia may not be a point specific effect.

Traditional Chinese veterinary medicine: the mechanism and management of acupuncture for chronic pain

Complementary and alternative medicine can be defined as the diagnosis, treatment, and/or prevention that complements mainstream medicine, satisfying a demand not met by orthodoxy and diversifying the conceptual framework of medicine. Acupuncture is being used much more commonly now as a sole or integrative modality in veterinary medicine and can play a large role in management of inflammation and chronic pain. Western medical etiology, pathophysiology, diagnosis, and treatment should be considered before applying acupuncture. This article describes the evolving biomedical basis of acupuncture analgesia and gives the practitioner an overview of how acupuncture can be performed in a medical setting.

On the threshold - evaluation of variability in effects of acupuncture in a gender perspective

Variable results of pain alleviation in response to acupuncture have been reported, complicating its interpretation. Sources of variability are probably multi-factorial, including the contribution of gender related effects. Gender related variation in perceived pain has been discussed frequently, but documented effects of acupuncture referring to gender are sparse. Furthermore, factors such as operationalisation of the outcome variable and the statistical method for evaluation could also be sources of variability. When pain is regarded as subjective, the produced data should be treated as ordinal. The rank-based method by Svensson, taking the non-metric qualities of the ordinal data into account as well as the variability at the group and the individual level, is therefore an alternative. The present commentary aims to (1) evaluate changes in electrical sensory thresholds and electrical pain thresholds after low frequency electro-acupuncture separately in healthy women and men; (2) introduce and exemplify the method by Svensson in a user-friendly approach. To analyze the systematic patterns of change in thresholds, indicating evidence of treatment on a group level, the relative position (RP) and relative concentration (RC), were measured. The variation related to the individual, the relative rank variation (RV) was also measured. The results were divergent between women (n = 23) and men (n = 22), i.e. unchanged sensory threshold after acupuncture at the group level in women while changed in men. The assessed pain threshold after acupuncture on the other hand was changed towards higher levels in women and unchanged in men. The individual variation was apparent in both women and men but larger in women. For statistical analysis of the variability for both group and individual related effects, the rank-based method by Svensson could be used. The present study indicates that evaluation of sensory and pain threshold response should be analysed separately in women and men.

Bilateral acupuncture analgesia observed by quantitative sensory testing in healthy volunteers

BACKGROUND

There is evidence that acupuncture activates different spinal and supraspinal antinociceptive systems, but the specific modulatory effects on the sensory system have not been systematically investigated. In this study, we evaluated the immediate effects of different types of acupuncture on thermal, mechanical, and vibratory sensory thresholds.

METHODS

Twenty-four healthy volunteers (12 men and 12 women, mean age 33.1 years) received 3 different forms of acupuncture in a single-blinded crossover design; these included manual acupuncture, acupuncture with low-frequency electrical stimulation, and acupuncture with high-frequency electrical stimulation. The time between the interventions was 1 week. All forms of acupuncture were applied unilaterally in the leg at standard acupuncture points: spleen 6, spleen 9, stomach 36, and gallbladder 39. The effects of acupuncture were evaluated by systematic quantitative sensory testing (QST) immediately after each intervention. QST was performed on bilateral lower extremities, including thermal and mechanical perception and pain and vibratory thresholds.

RESULTS

The heat pain threshold was increased after manual acupuncture on the treated and untreated side compared with baseline. Low- and high-frequency electrostimulation led to a higher mechanical pain threshold on the treated side compared with baseline and manual acupuncture. The pressure pain threshold was increased by all forms of acupuncture on both sides, with individual changes from baseline ranging from 25% to 52%.

CONCLUSIONS

There were congruent changes on QST after 3 common acupuncture stimulation methods, with possible unilateral as well as bilateral effects.

The impact of asynchronous electroacupuncture stimulation duration on cold thermal pain threshold

The durations of asynchronous electroacupuncture can affect the resultant hypoalgesia. Healthy volunteers were randomized to receive different durations (0 min, 20 min, 30 min, or 40 min) of asynchronous electroacupuncture stimulations (alternating low/high [2/100 Hz] frequency at 5 mA). Using a human experimental cold thermal pain threshold model, we found that 30 min of asynchronous 2/100 Hz stimulation resulted in the most significant hypoalgesic effect that was sustained for at least 60 min after stimulation compared with 0-, 20-, or 40-min stimulations (P < 0.05). We conclude that the most optimal duration for asynchronous electroacupuncture stimulation is 30 min.

Effects of acupuncture on symptoms and muscle function in delayed-onset muscle soreness

OBJECTIVE

This study was done to investigate the effects of a standardized acupuncture treatment on symptoms and muscle function in exercise-induced delayed-onset muscle soreness (DOMS).

METHODS

A prospective, randomized, controlled, observer and subject-blinded trial was undertaken. Twenty-two (22) healthy subjects (22-30 years; 10 males and 12 females) were randomly assigned to three treatment groups: real acupuncture (deep needling at classic acupuncture points and tender points; n = 7), sham-acupuncture (superficial needling at nonacupuncture points; n = 8), and control (no needling; n = 7). DOMS of the nondominant elbow-flexors was experimentally induced through eccentric contractions until exhaustion. The outcome measures were pain perception (visual analogue scale; VAS; range: 0-10 cm), mechanical pain threshold (MPT; pressure algometer), and maximum isometric voluntary force (MIVF; force transducer). Treatment was applied immediately, 24 and 48 hours after DOMS induction. Measurements of MPT and MIVF were made prior to DOMS induction as well as before and after every treatment session. VAS data were acquired after DOMS induction as well as pre- and post-treatment. Final pain, MPT, and MIVF measurements were performed 72 hours after DOMS induction.

RESULTS

Following nonparametric testing, there were no significant differences between groups in outcome measures at baseline. After 72 hours, pain perception (VAS) was significantly lower in the acupuncture group compared to the sham acupuncture and control subjects. However, the mean MPT and MIVF scores were not significantly different between groups.

CONCLUSIONS

Although acupuncture seemed to have no effects on mechanical pain threshold and muscle function, it proved to reduce perceived pain arising from exercise-induced muscle soreness.