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Spinal Cord Mechanism Involving the Remote Effects of Dry Needling on the Irritability of Myofascial Trigger Spots in Rabbit Skeletal Muscle
Abstract
To elucidate the neural mechanisms underlying the remote effects produced by dry needling rabbit skeletal muscle myofascial trigger spots (MTrSs) via analyses of their endplate noise (EPN) recordings.
Experimental animal controlled trial.
An animal laboratory of a university.
Male New Zealand rabbits (N=96) (body weight, 2.5-3.0kg; age, 16-20wk).
Animals received no intervention for neural interruption in group I, transection of the tibial nerve in group II, transection of L5 and L6 spinal cord in group III, and transection of the T1 and T2 spinal cord in group IV. Each group was further divided into 4 subgroups: animals received ipsilateral dry needling, contralateral dry needling, ipsilateral sham needling, or contralateral sham needling of gastrocnemius MTrSs.
EPN amplitudes of biceps femoris (BF) MTrSs.
BF MTrS mean EPN amplitudes significantly increased (P<.05) initially after gastrocnemius verum needling but reduced to a level significantly lower (P<.05) than the preneedling level in groups I and IV with ipsilateral dry needling or contralateral dry needling, and in group II with contralateral dry needling (but not ipsilateral dry needling). No significant EPN amplitude changes were observed in BF MTrS in group III or in the control animals receiving superficial needling (sham).
This remote effect of dry needling depends on an intact afferent pathway from the stimulating site to the spinal cord and a normal spinal cord function at the levels corresponding to the innervation of the proximally affected muscle.
... Further analysis indicated that the main research direction of China Medicine University was the remote effect of acupuncture on the irritability of MTrPs and the spinal cord mechanism. [37][38][39] The centralities of all institutions were low. The institutions of China Medicine University and Hungkuang University had the strongest cooperation, while cooperation among other institutions should be further strengthened. ...
... Among the ten authors, Liwei Chou, Changzern Hong, Yuehling Hsieh and Chenchia Yang all came from Taiwan and had close DovePress cooperation with each other on the remote effects and mechanism of dry needling at myofascial trigger points. 22,38,40,41 Their researches revealed that acupuncture had remote effectiveness on suppressing the myofascial trigger point irritability and this effect may be related to the normal spinal cord function, interactions within the endogenous opioid system and biochemicals associated with pain, inflammation, and hypoxia. The links showed that the cooperation between authors in this field was not close. ...
... effect of dry needling in the treatment of myofascial pain syndrome: a randomized doubleand dry needling in the management of myofascial trigger point pain: A systematic review and meta-analysis of randomised controlled trials38 Tough EA (2009) Map of keywords occurrence related to acupuncture on MPS from 2000 to 2022. The nodes represent key words, and the lines between the nodes represent the co-occurrence relationships. ...
Background
Acupuncture has been widely used to relieve myofascial pain syndromes (MPS) in many countries. However, the bibliometric analysis of the global application of acupuncture for MPS remains unknown.
Purpose
The present study aims to evaluate the research trends and hot spots of acupuncture for MPS.
Methods
Literatures about acupuncture for MPS from 2000 to 2022 were obtained from the Web of Science. CiteSpace (6.1.R3) was used to analyze the number of publications, countries, institutions, authors, cited journals, cited authors, cited references and keywords.
Results
A total of 403 records were included in the final analysis. The total number of publications increased but with some fluctuations. The Pain was the most cited journals. The most productive country and institution were USA, and China Medicine University, respectively. Liwei Chou was the most prolific author, and Simons DG ranked first in the cited author. In the ranking of frequency and centrality in cited references, the first article was published by Tough EA and Simons DG, respectively. The keyword of “acupuncture” ranked first in frequency, “double blind” ranked first in centrality. “Meta-analysis” was the keyword with the strongest citation burst. There were three hot topics in this field, including “the clinical feature of MPS”, “measure of intervention” and “research method”. The mechanism of acupuncture on MPS was one of the main research directions.
Conclusion
This study reveals that acupuncture was more and more acceptable, while the cooperation between different countries, institutions and authors should be strengthened. The researches of therapeutic effect and mechanism were the main research directions. More high-quality clinical trials are needed to confirm the therapeutic effect of acupuncture for MPS, and more studies to unify the acupuncture parameters such as frequency, duration, and intensity. More basic studies are needed to elucidate the precise mechanism of acupuncture for MPS.
... the neurophysiological mechanism of DN emphasizes the modulation of the biochemical environment of the MtrP in a dose-dependent manner. this includes enhancing β-endorphin levels in the target muscle and serum, reducing substance P in the target muscle and dorsal root ganglion, and activating the inhibitory pathway at the spinal cord level [57,58]. inserting DN at a distance from the symptomatic MtrPs may activate the descending inhibitory pain pathway, leading to the relief of remote pain [59]. ...
... hsieh et al. demonstrated that inserting DN into distant myofascial trigger points can relieve symptoms by reducing substance P levels in both proximal muscle and spinal cord [60]. an electrophysiological study focusing on the remote effect of DN found that if the afferent pathway is intact, the endplate noise of the proximally affected muscle decreased [57]. We hypothesize that the reduced BPe after DN in our research may be related to the mechanical mechanism majority. ...
Introduction
Long head of biceps brachii tendinopathy, a frequent source of anterior shoulder pain, may lead to discomfort and diminished function. The objective of this study is to assess the efficacy of dry needling and transcutaneous electrical nerve stimulation in these patients.
Patients and methods
Thirty patients were randomized into dry needling and transcutaneous electrical nerve stimulation groups and assessed before treatment, 8 and 15 days after treatment using a visual analogue scale, shoulder pain and disability index, pressure pain threshold, tissue hardness, and biceps peritendinous effusion.
Results
Both treatments significantly reduced the visual analogue scale in immediate (p < 0.001), short-term (p < 0.01), and medium-term effects (p < 0.01). Dry needling outperformed transcutaneous electrical nerve stimulation for the pain (p < 0.01) and disability (p < 0.03) subscales of the shoulder pain and disability index in the short-term and medium-term effects, respectively. Pressure pain threshold increased after both treatments but didn’t last beyond 8 days. Neither treatment showed any improvements in tissue hardness of the long head of biceps brachii muscle. Notably, only the dry needling group significantly reduced biceps peritendinous effusion in both short-term and medium-term effects (p < 0.01).
Conclusions
Dry needling showed non-inferior results to transcutaneous electrical nerve stimulation in reducing pain and disability and demonstrated even superior results in reducing biceps peritendinous effusion (see Graphical Abstract).
Trial registration
The Institutional Review Board of the China Medical University Hospital (CMUH107-REC2-101) approved this study, and it was registered with Identifier NCT03639454 on ClinicalTrials.gov.
... In subjects with MTrPs, DN has been reported to decrease pain [12]. e possible physiological effects of DN involve both mechanical stimulation and the consequences of local microtrauma. ...
... LTR is an involuntary spinal reflex that results in a localized contraction of affected muscle fibers that are manually stretched with dry needles. Both Chen et al. [6] and Hsieh et al. [12] demonstrated in their studies with rabbit that DN to a MTrP region could effectively suppress SEA, when LTRs were elicited. ey suggested that inserting a needle into the endplate region may lead to increased discharges and thus immediately reduce available ACh stores, leading to a decrease in the SEA. ...
Numerous studies have suggested that the myofascial trigger points are responsible for most of the myofascial pain syndrome, so it seems reasonable that its destruction is a good therapeutic solution. The effectiveness of dry needling (DN) has been confirmed in muscles with myofascial trigger points, hypertonicity, and spasticity. The objective of this study is to analyze the need of repetitive punctures on muscles in different situations. The levator auris longus (LAL) muscle and gastrocnemius muscle from adult male Swiss mice were dissected and maintained alive, while being submerged in an oxygenated Ringer’s solution. DN was evaluated under four animal models, mimicking the human condition: normal healthy muscles, muscle fibers with contraction knots, muscles submerged in a depolarizing Ringer solution (KCl-CaCl2), and muscles submerged in Ringer solution with formalin. Thereafter, samples were evaluated with optical microscopy (LAL) and scanning electron microscopy (gastrocnemius). Healthy muscles allowed the penetration of needles between fibers with minimal injuries. In muscles with contraction knots, the needle separated many muscle fibers, and several others were injured, while blood vessels and intramuscular nerves were mostly not injured. Muscles submerged in a depolarizing solution inducing sustained contraction showed more injured muscular fibers and several muscle fibers separated by the needle. Finally, the muscles submerged in Ringer solution with formalin showed a few number of injured muscular fibers and abundant muscle fibers separated by the needle. Scanning electron microscopy images confirm the optical analyses. In summary, dry needling is a technique that causes mild injury irrespective of the muscle tone.
... 4,[11][12][13][14][29][30][31] Mechanical needling was employed to scrape away the calcification and fibrosis, and sterile water injection resulted in significantly more disintegration, as well as changes in the neurochemistry of deeper tissue structures, 32-37 possibly improving the analgesic effect. [32][33][34][35][36][37] Mechanical needling may diminish both peripheral and central sensitization by reducing the source of peripheral nociception, such as the trigger point (TrP) region, facet joint calcification, and fibrosis, modifying spinal dorsal horn activity, and activating the central inhibitory pain pathway. When a needle is inserted into the body, it causes a variety of natural neurophysiological responses, including stimulation of the A and C fibers and activation of cortical brain areas. ...
... When a needle is inserted into the body, it causes a variety of natural neurophysiological responses, including stimulation of the A and C fibers and activation of cortical brain areas. [32][33][34][35][36][37] The water jet procedure can help eliminate calcification and fibrosis from the facet joint, nerves, and muscles by using sterile water. The procedure's efficacy was seen to last up to 6 months in this investigation. ...
Study Design: This was a retrospective observational study that assessed the clinical outcome of ageing patients who received ultrasound-guided (USG) mechanical needling with sterile water injection. In addition, the clinical outcome of age-and gender matched patients randomly selected from patients who received needling with sterile water was compared to the patients injected with lidocaine in a 1:1 ratio.
Objective: This present study aimed to explore the clinical effects of USG mechanical needling with sterile water injection for lumbar spinal stenosis (LSS).
Methods: The data was extracted from the medical records of ageing patients with LSS who received USG injection at the lumbosacral spine by the first author. Low back pain or axial pain, and leg pain or radicular pain were assessed by the visual analogue scale, and gait ability with walking distance were obtained at six different time points.
Results: A total of 4328 medical records were examined. Four thousand two hundred and twenty-eight ageing patients received mechanical needling with sterile water injection and found the efficacy lasted up to 6 months. One hundred patients were compared with 100 patients who received lidocaine injection. Those who received lidocaine had pain returned at 3 months and 6 months post-injection.
Conclusions: USG mechanical needling with sterile water injection could help relieve axial and radicular pain for at least 6 months. Removal of calcification and fibrosis as well as reduction of sensitization are all possible mechanisms.
... In this study, the USG mechanical needling with injection of sterile water may break the myofascial trigger points, reduce sensitization of the muscles and soft tissue at the facet joints, and block the medial branches of the dorsal rami that innervate the facet joints. e mechanical needling and sterile water can reduce peripheral and central sensitization and might create the mechanical effect of removing calcification and fibrosis around the facet joints [9,[24][25][26] and alter the neurochemistry [9,[24][25][26][27][28][29][30][31][32][33][34] of the deeper tissue structures that may provide an enhanced analgesic response [30][31][32][33][34]. From a neurophysiological standpoint, mechanical needling may reduce both peripheral and central sensitization by removing the source of peripheral nociception, such as the trigger point (TrP) region, calcification, and fibrosis of the facet joint, as seen in this study, changing spinal dorsal horn activity, and activating central inhibitory pain pathways. e insertion of a needle into the body is known to elicit a variety of natural neurophysiological mechanisms, such as stimulation of the A and C fibers or activation of cortical brain areas [9,10,[24][25][26][27][28][29][30][31][32][33][34][35][36]. ...
... e mechanical needling and sterile water can reduce peripheral and central sensitization and might create the mechanical effect of removing calcification and fibrosis around the facet joints [9,[24][25][26] and alter the neurochemistry [9,[24][25][26][27][28][29][30][31][32][33][34] of the deeper tissue structures that may provide an enhanced analgesic response [30][31][32][33][34]. From a neurophysiological standpoint, mechanical needling may reduce both peripheral and central sensitization by removing the source of peripheral nociception, such as the trigger point (TrP) region, calcification, and fibrosis of the facet joint, as seen in this study, changing spinal dorsal horn activity, and activating central inhibitory pain pathways. e insertion of a needle into the body is known to elicit a variety of natural neurophysiological mechanisms, such as stimulation of the A and C fibers or activation of cortical brain areas [9,10,[24][25][26][27][28][29][30][31][32][33][34][35][36]. e mechanical needling with sterile water action as the water jet mechanism can clear the calcification and fibrosis from the facet joint, nerves, and muscle. ...
Objective. This present study aimed to explore the clinical effects of ultrasound-guided (USG) mechanical needling with sterile water injection for lumbar facet joint syndrome. Methods. This was a retrospective cohort study that assessed the clinical outcome of ageing patients who received USG mechanical needling with sterile water injection. In addition, the clinical outcome of age- and gender-matched patients randomly selected from patients who received mechanical needling with sterile water was compared to the patients injected with steroids in a 2 : 1 ratio. The data were extracted from the medical records of ageing patients with facet joint syndrome who received USG injection at the lumbosacral spine by the first author. Low back pain or axial pain, and leg pain or radicular pain were assessed by the visual analogue scale (VAS), and gait ability with walking distance was obtained at 6 different time points. Results. A total of 4,276 medical records were examined. Four thousand two hundred twenty-eight ageing patients received needling with sterile water injection and found that the efficacy lasted up to 6 months. Ninety-six patients were compared with 48 patients who received steroid injection. Those who received steroids had less back and leg pain at 1 week after injection; however, pain returned at 3 months and 6 months after injection. Conclusions. USG mechanical needling with sterile water could help relieve axial and radicular pain for at least 6 months. Reduced sensitization and removal of calcification and fibrosis were all possible mechanisms.Keywords: Mechanical needling, Sterile water, Ultrasound guided (USG) injection, Facet joint syndrome, Pain
... Both types of fascial-ligament trigger points have a very similar pathogenetic mechanism, and in the proximity of the subjective manifestation, some authors combine them under the name of myofibrillar pain syndrome [6]. A number of researches [11] have shown that long-standing myogenic and fascial ligament hypertonia lead to fibrous degeneration of muscle tissue. It is known [3] that local, latent muscle pain has a local manifestation and occurs when stretching and local pressure. ...
... Our data are consistent with the results of researches by other authors [6,11], which indicate that such people often have excessive combined involvement in the contractile activity of near and far agonists, which is manifested by regional muscular-tonic reactions and they have no adaptive value. In our opinion, the increased synergistic activity of agonists reciprocally creates an effect on antagonists, forming pathological coordination complexes. ...
Myofascial pain syndrome (MFPS) is one of the most common comorbid pathological processes that develops in skeletal muscle in patients with stroke, which is manifested by local seals and pain in various parts of the muscle. Despite the fact that the interest in MFPS arose in the last century, the intimate mechanisms of its development and course remain to be fully explored. It was found that the main manifestations of MFPS were the presence of miofascial trigger point in the area of palpation of the corresponding muscle with local pain and hypersensitivity within the palpated cord-segmentes, the characteristic pattern of reflected pain and reflected autonomic phenomenon, local convulsive response during transverse palpation. It is accompanied by muscle fatigue and significant muscle weakness without severe atrophy. Attention is drawn to the clear recurrence-reproducibility of pain, ie the so-called "recognizable" pain. All of the above symptoms constitute a general pattern of the disease, which has diagnostic value and is proposed for use as prognostic parameters with the obligatory use of the results of electromyographic examination. Diagnosis of active and latent MTP was performed on the basis of generally accepted l signs. The greatest discomfort for the patient is the presence of active MTP with characteristic spontaneously reproducing pain. Latent MTP is detected in up to 90% of cases among healthy people, and adverse factors only contribute to their transition to an active state with a characteristic symptom complex. The presence of an active myofascial trigger point with a characteristic spontaneously reproducing pain is the most painful manifestation. Latent MTP is also detected in most cases among healthy people, and unfavorable factors only contribute to their transition to an active state with a characteristic symptom complex. The study of the number of turns of the adhesive part of the potential in the zone of active ICC showed that there is a concentration of fibers in the zone of one motor units (MU). The average value of this indicator increases in the early stages of the process by 2 times. Even a small degree of desynchronization of the potentials of individual MU causes an increase in the number of rounds, which reflects the number of fibers involved in the generation of MC PMU. Absence of spontaneous muscle fibers (MF) activity, registration of end plate (EP) activity, PMU parameters such as amplitude decrease, shift of neurohistogram of potential distribution by duration towards smaller values or high percentage of polyphasicity, due to increase in number of turns, and also change their adhesive part, increase of MF density in zone MTP - they all determine changes in structural and functional parameters by muscle type. The work is devoted to the clinical, neuro-physiological characteristics of a patient with MFPS on the background of intracerebral hemorrhage and left hemyplegia based on the analysis of the neuro-functional organization of the motor units of the back muscles. Substantiated genesis and possible mechanism of development and formation of myofascial trigger point in such patients.
... After MMP induction, manual palpation was performed and electrophysiological recordings were made to identify myofascial trigger points in the rat's masseter muscle for confirming the establishment of a rat MMP model according to the methods published in previous studies [44,45]. Briefly, animal was under anesthesia and its masseter muscle was grasped between fingers from behind the muscle, which was palpated by gently rubbing (rolling) to find a taut band. ...
... The procedure for measuring EPN prevalence was conducted as described previously [45]. After initial insertion, the needle was advanced very slowly under gentle rotation. ...
Masticatory myofascial pain (MMP) is one of the most common causes of chronic orofacial pain in patients with temporomandibular disorders. To explore the antinociceptive effects of ultra-low frequency transcutaneous electrical nerve stimulation (ULF-TENS) on alterations of pain-related biochemicals, electrophysiology and jaw-opening movement in an animal model with MMP, a total of 40 rats were randomly and equally assigned to four groups; i.e., animals with MMP receiving either ULF-TENS or sham treatment, as well as those with sham-MMP receiving either ULF-TENS or sham treatment. MMP was induced by electrically stimulated repetitive tetanic contraction of masticatory muscle for 14 days. ULF-TENS was then performed at myofascial trigger points of masticatory muscles for seven days. Measurable outcomes included maximum jaw-opening distance, prevalence of endplate noise (EPN), and immunohistochemistry for substance P (SP) and μ-opiate receptors (MOR) in parabrachial nucleus and c-Fos in rostral ventromedial medulla. There were significant improvements in maximum jaw-opening distance and EPN prevalence after ULF-TENS in animals with MMP. ULF-TENS also significantly reduced SP overexpression, increased MOR expression in parabrachial nucleus, and increased c-Fos expression in rostral ventromedial medulla. ULF-TENS may represent a novel and applicable therapeutic approach for improvement of orofacial pain induced by MMP.
... -Study design: RTCs with a minimum score of 7 in 74 the PEDro scale, corresponding to high method-75 ological quality [21]. 76 The studies were excluded if they: included patients 77 with concomitant conditions, included healthy subjects, 78 used surgical or pharmacological interventions as their 79 primary intervention, did not explain or did not con- 80 trol basic pharmacological treatment prescribed by a 81 medical doctor. Potentially relevant studies were screened by two 84 independent reviewers that selected studies based on 85 title and abstract. ...
... 462 The reduction of peripheral nociception would decrease 463 the neuron activity in the dorsal horn of the spinal cord. 464 This fact may explain the improvements in pain-related 465 variables and other symptoms [12,80]. 466 Strong evidence suggested that PE, through accep-467 tance and commitment therapy, reduces disability and 468 depression. ...
Background:
Fibromyalgia is a chronic condition characterized by generalized pain. Several studies have been conducted to assess the effects of non-pharmacological conservative therapies in fibromyalgia.
Objective:
To systematically review the effects of non-pharmacological conservative therapies in fibromyalgia patients.
Methods:
We searched MEDLINE, Cochrane library, Scopus and PEDro databases for randomized clinical trials related to non-pharmacological conservative therapies in adults with fibromyalgia. The PEDro scale was used for the methodological quality assessment. High-quality trials with a minimum score of 7 out of 10 were included. Outcome measures were pain intensity, pressure pain threshold, physical function, disability, sleep, fatigue and psychological distress.
Results:
Forty-six studies met the inclusion criteria. There was strong evidence about the next aspects. Combined exercise, aquatic exercise and other active therapies improved pain intensity, disability and physical function in the short term. Multimodal therapies reduced pain intensity in the short term, as well as disability in the short, medium and long term. Manual therapy, needling therapies and patient education provided benefits in the short term.
Conclusions:
Strong evidence showed positive effects of non-pharmacological conservative therapies in the short term in fibromyalgia patients. Multimodal conservative therapies also could provide benefits in the medium and long term.
... This technique was originally developed to inactivate an MTrP in the upper trapezius by needling the MTrP at the ipsilateral forearm following the principle of acupuncture; it can also be applied in direct needling of an MTrP. When this techniques was developed, it was found that irritability (measured as subjective pain intensity, pain threshold, and amplitude change of EPN) of the MTrP in the upper trapezius muscle could be suppressed after needling remote acupoints [41]; this effectiveness was also confirmed by animal study [60,61]. This technique is further recommended for myofascial pain therapy, a simple and rapid way to relieve chronic pain, using low-cost medical supplies. ...
... The mechanisms by which DN can reduce spasticity is not completely known [11]. One possible is that DN regulates neuronal activity in the levels of spinal cord [12] or supraspinal centers [13,14]. Recently, studies have shown that DN influences brain activity using functional magnetic resonance imaging (fMRI) [15,16]. ...
Background
Dry needling is an intervention used by physiotherapists to manage muscle spasticity. We report the effects of three sessions of dry needling on ankle plantar flexor muscle spasticity and cortical excitability in a patient with multiple sclerosis.
Case presentation
The patient was a 40-year-old Iranian woman with an 11-year history of multiple sclerosis. The study outcomes were measured by the modified modified Ashworth scale, transcranial magnetic stimulation parameters, and active and passive ankle range of motion. They were assessed before (T0), after three sessions of dry needling (T1), and at 2-week follow-up (T2). Our result showed: the modified modified Ashworth scale was improved at T2 from, 2 to 1. The resting motor threshold decreased from 63 to 61 and 57 at T1 and T2, respectively. The single test motor evokes potential increased from 76.2 to 78.3. The short intracortical inhibition increased from 23.6 to 35.4 at T2. The intracortical facilitation increased from 52 to 76 at T2. The ankle active and passive dorsiflexion ROM increased ~ 10° and ~ 6° at T2, respectively.
Conclusion
This case study presented a patient with multiple sclerosis who underwent dry needling of ankle plantar flexors with severe spasticity, and highlighted the successful use of dry needling in the management of spasticity, ankle dorsiflexion, and cortical excitability. Further rigorous investigations are warranted, employing randomized controlled trials with a sufficient sample of patients with multiple sclerosis.
Trial registration IRCT20230206057343N1, registered 9 February 2023, https://en.irct.ir/trial/68454
... This amelioration in muscle stiffness may be due to local twitch responses, which have been shown to change the length and tension of the muscle fibers [43]. Local twitch responses, elicited by the mechanical needling activation of the muscle fibers around the end plate, have also been shown to suppress spontaneous electrical activity in AMTrPs [44,45]. It has been hypothesized that the amelioration of blood circulation after DN is related to the release of vasoactive substances, such as the calcitonin gene-related peptide which, upon activation of Aδ-and C-fibers, generates vasodilatation in small vessels [46]. ...
Tension-type headache is the most prevalent type of headache and is commonly associated with myofascial pain syndrome and the presence of active myofascial trigger points. This randomized controlled trial aimed to assess the impact of dry needling on the total number of active trigger points, pain intensity, and perceived clinical change in tension-type headache subjects. Thirty-two subjects were randomly assigned to the control and dry needling groups. The presence of active trigger points in 15 head and neck muscles, the headache intensity, and the perceived clinical change were evaluated. A single dry needling technique was administered at each active trigger point across three sessions. Significant differences were observed in the post-treatment measures favouring the dry needling group, including reductions in the headache intensity scores (p = 0.034) and the total number of active trigger points (p = 0.039). Moreover, significant differences in the perception of clinical change were found between the control and treatment groups (p = 0.000). Dry needling demonstrated positive effects in reducing the number of active trigger points and improving the short-term headache intensity in tension-type headache patients. A single dry needling session applied in the cranio-cervical area resulted in a self-perceived improvement compared to the control subjects.
... Thus, the subscapularis muscle MTrPs can impair shoulder and hand function (11). DN, as a new intervention in the field of physiotherapy, has been shown to have a positive effect on increasing the ROM and reduction of pain in people with chronic shoulder pain (35)(36)(37). DN with vasodilation in small vessels may improve blood circulation and oxygen levels (38)(39)(40). With LTR, DN may regulate spontaneous electrical activity levels in active MTrPs and may suppress substance P and calcitonin-generated peptide levels in active MTrPs (41). ...
... Before an anesthetic was administered, the most tender spots (i.e., MTrPs) of randomly selected masseter muscles were identified via finger pinching. An animal's reaction (e.g., withdrawal of the lower limb, head turning, and screaming) was observed to confirm the exact location of an MTrP [22][23][24]. These painful regions were marked on the skin with an indelible marker, and the animals were anesthetized with isoflurane (AErrane, Baxter Healthcare of Puerto Rico, PR, USA) in oxygen flow (2% for induction and 0.5% for maintenance) [25]. ...
Needle electromyogram (EMG) research has suggested that endplate noise (EPN) is a characteristic of myofascial trigger points (MTrPs). Although several studies have observed MTrPs through ultrasonography, whether they are hyperechoic or hypoechoic in ultrasound images is still controversial. Therefore, this study determined the echogenicity of MTrP ultrasonography. In stage 1, the MTrP of rat masseter muscle was identified through palpation and marked. Needle EMG was performed to detect the presence of EPN. When EPN was detected, ultrasound scans and indwelling needles were used to identify the nodule with a different grayscale relative to that of its surrounding tissue, and the echogenicity of the identified MTrP was determined. In stage 2, these steps were reversed. An ultrasound scan was performed to detect the nodule at the marked site, and an EMG needle was inserted into the nodule to detect EPN. There were 178 recordings in each stage, obtained from 45 rats. The stage 1 results indicate that the MTrPs in ultrasound images were hypoechoic with a 100% sensitivity of assessment. In stage 2, the accuracy and precision of MTrP detection through ultrasonography were 89.9% and 89.2%, respectively. The results indicate that ultrasonography produces highly accurate and precise MTrP detection results.
... In addition, flexibility means the muscle's ability to increase its length and allow the joint to move along the range of motion [59]. Hence, the possible mechanisms of dry needle effect, which cause short muscle flexibility and subsequent improvement of ROM, might be muscle relaxation following neurological factors caused by dry needle effect on the muscle that stimulates sensory fibers and its transfer to higher centers [19,60,61], sarcomere returning to rest length with disruption of cytoskeletal structures and decreasing actin and myosin overlap (mechanical theory) and increasing blood flow and oxygen delivery that counteract muscle contraction (neurophysiological theory) [62][63][64]. ...
Introduction: Forward head posture (FHP) is one of the most common positional deviations. Frequent users often exhibit incorrect posture because of the rising popularity of media devices, such as smartphones and computers. This posture leads to changes in muscle activity in cervical flexion and extension. It is defined by hyperextension of the upper cervical vertebrae and forward translation of the cervical vertebrae. This study evaluates the effect of dry needles as a new method in the upper trapezius muscle on the neck’s angles and range of motion (ROM) in individuals with FHP Materials and Methods: In this quasi-experimental interventional study, 18 women with FHP underwent a dry needle session. The photogrammetry of the cranio-vertebral angle measured the degree of FHP. Visual analog scale (VAS), pain pressure threshold (PPT), cranio-vertebral angle (CVA) and cranio-horizontal angles (CHA), ROM, scapular index (SI), and forward shoulder translation (FST) were assessed before and after the intervention. Results: The results demonstrated that after the intervention, right and left PPT, flexion, and proper neck rotation, right and left SI, CVA, and CHA were significantly improved (P<0.05). Conclusion: The results showed that one session of dry needling with stretching exercises intervention could improve PPT, ROM, SI, CVA, and CHA and consequently improve FHP.
... An hypoalgesic effect of PE at a point segmentally related to the treatment area (e.g., cervical spine for the elbow) has been previously found (Varela-Rodríguez et al., 2022), but the novelty of the current study is that changes were detected bilaterally (mirror effect). Bilateral effects have been reported previously in studies involving other needle techniques such as dry needling, electro-acupuncture or percutaneous electrical nerve stimulation (Audette et al., 2004;De-la-Cruz-Torres et al., 2021;Hsieh et al., 2011;Koo et al., 2002) suggesting that these procedures generate spinal cord mechanisms. ...
... The author map was generated after analyzing 21,22 This efficacy depends on the integrity of the afferent pathway from the stimulation site to the spinal cord, as well as the normal function of the spinal cord at the corresponding level of muscle innervation. 23 In addition, DN is involved in the regulation of various biochemicals associated with pain, inflammation and hypoxia. 24,25 Notwithstanding, the map of author collaboration highlights a less than optimal level of cooperation amongst the authors. ...
Background
Evidence has shown that dry needling (DN) is effective for myofascial pain syndrome (MPS). However, bibliometrics has rarely been used to analyze the literature related to DN for MPS. The purpose of this study is to provide a systematic overview of global frontiers and research hotspots of DN in the treatment of MPS from 2000 to 2022.
Methods
A search was conducted on Web of Science Core Collection (WoS CC) for literature on DN for MPS from 2000 to 2022. Based on the basic information provided by WoS CC, CiteSpace software was used to conduct bibliometric analysis of the countries, institutions, categories, journals, authors, references and keywords involved in this topic.
Results
A total of 458 papers were obtained, with the number of publications increasing over time. Journal of Bodywork and Movement Therapies (31) was the most productive journal based on the number of publications, while Arch Phys Med Rehab (329) was the most co-cited journal. The most productive countries and institutions were USA (112) and Universidad Rey Juan Carlos (39), respectively. Fernandez-de-las-penas, Cesar has the highest number of publications (24) and Simons DG, who was an author with the highest number of citations (250). The article published by Gattie et al (co-citations: 65), and Mejuto-Vazquez et al (centrality: 0.36) were the most representative and symbolic. Based on the co-cited literature and keywords, myofascial trigger point, research methods, and acupuncture were the hot research topics and trends in the field.
Conclusion
The current status and trends in clinical research of DN for MPS are revealed according to the results of this bibliometric study, which may facilitate researchers to identify hot topics and new directions for future research.
... Open access increase endplate discharge and local blood flow, reduce spontaneous electrical activities and acetylcholine stores, and change the release of descending inhibitory neurotransmitters as well as the central and peripheral sensitisation process. [7][8][9] Cerezo-Téllez et al's study on 130 non-specific neck pain patients showed that DN can effectively reduce pain intensity, mechanical hyperalgesia, neck active angle of motion and muscle strength at 1, 3 and 6 months postoperatively. 6 Several meta-analysis results also supported the use of DN, especially deep DN, in the management of chronic MPS. ...
Introduction
Myofascial pain syndrome (MPS), especially in the neck and shoulder region, is one of the most common chronic pain disorders worldwide. Dry needling (DN) and pulsed radiofrequency (PRF) are the two effective methods for treating MPS. We aimed to compare the effects of DN and PRF in chronic neck and shoulder MPS patients.
Methods and analysis
This is a prospective, single-centre, randomised, controlled trial in a tertiary hospital. We plan to recruit 108 patients aged 18–70 years who are diagnosed with chronic MPS in the neck, shoulder and upper back regions and randomly allocate them to either the DN or PRF group at a 1:1 ratio. The DN group will receive ultrasound-guided intramuscular and interfascial DN 8–10 times per pain point or until local twitch responses are no longer elicited and 30 min of indwelling. The PRF group will receive ultrasound-guided intramuscular (0.9% saline 2 mL, 42℃, 2 Hz, 2 min) and interfascial (0.9% saline 5 mL, 42℃, 2 Hz, 2 min) PRF. Follow-up will be performed by the research assistant at 0, 1, 3 and 6 months postoperatively. The primary outcome is the postoperative 6-month pain visual analogue score (0–100 mm). Secondary outcomes include pressure pain threshold measured by an algometer, Neck Disability Index, depression (Patient Health Questionnaire-9), anxiety (Generalised Anxiety Disorder-7), sleep status (Likert scale) and overall quality of life (36-Item Short Form Survey). Between-group comparisons will be analysed using either a non-parametric test or a mixed effects linear model.
Ethics and dissemination
This study was approved by the medical ethics committee of Peking Union Medical College Hospital (JS-3399). All participants will give written informed consent before participation. The results from this study will be shared at conferences and disseminated in international journals.
Trial registration number
NCT 05637047, Pre-results.
... None of the previous studies assessed this parameter to compare this result with them. The mechanisms for mentioned effectiveness of DN on spastic post-stroke patients should be investigated at central and peripheral levels, since researchers believe that DN has a remote effect and can be effective at distant points indirectly in addition to making changes in the place where the needle is inserted [42,65,66]. At the peripheral level, the muscle was examined; after the muscle puncture by the needle, the muscle fibers and the motor end plate are damaged, and an inflammatory reaction occurs, which takes about five to seven days to phagocytosis of the necrosis parts and tissue reconstruction occur [8]. ...
Purpose:
Evaluation the effects of dry needling on sonographic, biomechanical and functional parameters of spastic upper extremity muscles.
Methods:
Twenty-four patients (35-65 years) with spastic hand were randomly allocated into two equal groups: intervention and sham-controlled groups. The treatment protocol was 12-sessions neurorehabilitation for both groups and 4-sessions dry needling or sham-needling for the intervention group and sham-controlled group respectively on wrist and fingers flexor muscles. The outcomes were muscle thickness, spasticity, upper extremity motor function, hand dexterity and reflex torque which were assessed before, after the 12th session, and after one-month follow-up by a blinded assessor.
Results:
The analysis showed that there was a significant reduction in muscle thickness, spasticity and reflex torque and a significant increment in motor function and dexterity in both groups after treatment (p < 0.01). However, these changes were significantly higher in the intervention group (p < 0.01) except for spasticity. Moreover, a significant improvement was seen in all outcomes measured one-month after the end of the treatment in the intervention group (p < 0.01).
Conclusions:
Dry needling plus neurorehabilitation could decrease muscle thickness, spasticity and reflex torque and improve upper-extremity motor performance and dexterity in chronic stroke patients. These changes were lasted one-month after treatment.Trial Registration Number: IRCT20200904048609N1IMPLICATION FOR REHABILITATIONUpper extremity spasticity is one of the stroke consequences which interfere with motor function and dexterity of patient hand in activity of daily livingApplying the dry needling accompanied with neurorehabilitation program in post-stroke patients with muscle spasticity can reduce the muscle thickness, spasticity and reflex torque and improve upper extremity functions.
... According to Hong, (47,48) the formation of the MTrP and the taut band is controlled by the central nervous system through a "MTrP circuit" and, thus, stimulation with a needle can transmit a strong signal to the central nervous system to induce the powerful re ex of the LTR that will help to reorganize the control that the central nervous system exercises over the MTrP and the tight band, breaking the vicious circle of the "MTrP circuit". ...
The purpose was to determine the efficacy of deep dry needling (DDN) applied on an active myofascial trigger point (MTrP) versus a latent-MTrP versus a non-MTrP location, on pain reduction and cervical disability, in patients with chronic neck pain. A randomized, double-blind clinical trial design was used. A sample of 65 patients was divided into non-MTrP-DDN, active-MTrP-DDN and latent-MTrP-DDN groups. The visual analog scale (VAS), reproduction of the patient’s pain, number of local twitch responses, pressure pain threshold (PPT) and Neck Disability Index (NDI) were assessed before, during and after the intervention and up to 1 month post-intervention. The active-MTrP-DDN-group reduced pain intensity more than non-MTrP-DDN-group after a week and a month (p<0.01). Active-MTrP-DDN-group showed the greatest improvement in tibialis muscle PPT. An association was found with a higher percentage of subjects in whom their neck pain was reproduced when the active-MTrP (77.3%) and the latent-MTrP (81.8%) were treated. The application of DDN on an active-MTrP in the upper trapezius muscle shows greater improvements in pain intensity after one week and one month post-intervention, as well as lesser improvement in PPT in the tibialis muscle, compared to DDN applied in latent-MTrPs or outside of MTrPs in patients with neck pain
... Used often to treat myofascial pain and trigger/tender points, dry needling can be extremely painful for the patient (29), some might even call it abusive. In dry needling for myofascial trigger-points, a needle is often inserted forcefully and repeatedly deep into the trigger/tender point during a session (e.g., fast-in and fast-out/pistoning/sparrow pecking maneuver, possibly in a fan or cone shape), with the purpose of "destroying" the trigger point or trying to induce edema, positive inflammation, and self-healing processes; or aiming to relieve the pain through spinal cord afferent signaling or other mechanisms (42)(43)(44)(45). However, as many clinicians' experiences might indicate, these mysterious painful points recur a short while after treatment too often, if not in the same site, then in a different one. ...
Acupuncture is a minimally invasive therapeutic method that uses small caliber needles while inserting them through the skin into various areas of the body. Some empirical studies find evidence to support the use of acupuncture as a treatment for certain medical conditions, however, this peculiar practice is widely considered as the domain of alternative and non-evidence-based medicine. Several mechanisms have been suggested in an attempt to explain the therapeutic action of acupuncture, but the way in which acupuncture alleviates chronic non-cancer pain or psychosomatic and psychiatric disorders is not fully understood. A recent study suggested a theoretical model (coined “Fascial Armoring”) with a cellular pathway to help explain the pathogenesis of myofascial pain/fibromyalgia syndrome and functional psychosomatic syndromes. It proposes that these syndromes are a spectrum of a single medical entity that involves myofibroblasts with contractile activity in fascia and aberrant extracellular matrix (ECM) remodeling, which may lead to widespread mechanical tension and compression. This can help explain diverse psycho-somatic manifestations of fibromyalgia-like syndromes. Fascia is a continuous interconnected tissue network that extends throughout the body and has qualities of bio-tensegrity. Previous studies show that a mechanical action by needling induces soft tissue changes and lowers the shear modulus and stiffness in myofascial tissue. This hypothesis and theory paper offers a new mechanism for acupuncture therapy as a global percutaneous needle fasciotomy that respects tensegrity principles (tensegrity-based needling), in light of the theoretical model of “Fascial Armoring.” The translation of this model to other medical conditions carries potential to advance therapies. These days opioid overuse and over-prescription are ubiquitous, as well as chronic pain and suffering.
... Monitoring the endplate noise from rabbit myofascial trigger spots (MTrSs) with FSN intervention demonstrated that FSN to MTrSs of distal ipsilateral gastrocnemius muscle can initially increase the irritability of MTrS in proximal biceps femoris muscle, followed by a suppression effect after cessation of needling, but these observations were not found in the contralateral side [46]. is hypothesis was also supported in the study of Langevin and her colleagues [47], who hypothesized that mechanical coupling between the needle and connective tissue with winding of tissue around the needle during needle rotation transmits a mechanical signal to connective tissue cells that may explain local and remote, as well as long-term, effects of acupuncture. Unlike Hsieh and her colleagues' animal study of dry needling [48], the mechanism for the effectiveness of dry needling and acupuncture to MTrP-induced disorders was related to an intact neural network. e effectiveness of remote FSN may go through the piezoelectricity and mechanical connective tissue reaction instead of neural mechanism. ...
Background:
Chronic neck pain is a common musculoskeletal disorder caused by overuse of neck and upper back muscles or poor posture, and it is commonly combined with a limited range of motion in the neck and shoulders. Most cases will recover within a few days; however, the symptoms often recur easily. Fu's subcutaneous needling (FSN) is a new therapeutic approach used to treat patients with chronic neck pain. However, there is no solid evidence to support the effectiveness of FSN on chronic neck pain and disability.
Methods:
Participants (n = 60) with chronic neck pain for more than 2 months with pain intensity scored by visual analog scale (VAS) more than five were enrolled in this trial. Participants were equally randomized into the FSN or transcutaneous electrical nerve stimulation (TENS) group who received interventions once a day on day 1, day 2, and day 4. They were assessed by outcome measurements during pre- and post-treatment and followed up for 15 days.
Results:
The VAS was immediately reduced in the FSN and TENS groups and sustained for 15 days of follow-up (all P < 0.001). The immediate effects were also observed as the pressure pain threshold increased in the FSN group on day 2 (P=0.006) and day 4 (P=0.023) after treatment, and tissue hardness decreased by FSN on day 1 and day 2 after treatment (both P < 0.001). FSN and TENS treatment improved neck disability and mobility; moreover, FSN promoted participants to receive better sleep quality, as determined by PSQI assessment (P=0.030). TENS had no benefit on sleep quality.
Conclusion:
FSN was able to relieve pain and relax muscle tightness. Notably, FSN significantly improved neck disability and mobility and enhanced sleep quality. These findings demonstrated that FSN could be an effective alternative treatment option for patients with chronic neck pain. Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT03605576, registered on July 30, 2018.
... e potential role of DN is now reviewed from four different aspects in handling the activation of MTrPs: the spontaneous electrical activity (SEA), local ischemia and hypoxia, peripheral, and central sensitization. Both Hsieh et al. [23] and Sato et al. [24] demonstrated that DN may influence SEA when LTRs were elicited. ere are several mechanisms to explain the response of local muscles to blood flow during DN stimulation, but the most credible is the release of vasoactive substances which leads to vasodilatation in small vessels and increased blood flow [25]. ...
Objective:
To evaluate the safety and effectiveness of ultrasound-guided dry needling for trigger point inactivation in the treatment of postherpetic neuralgia (PHN) mixed with myofascial pain syndrome (MPS).
Methods:
A prospective and controlled clinical study was conducted. From January 2020 to December 2020, among the 100 patients who received PHN treatment in the pain department, 54 patients complicated with MPS were randomly divided into the dry needling group D (n = 28) and pharmacotherapeutic group P (n = 26). Visual analogue score (VAS) and McGill Pain Questionnaire (MPQ) were taken as primary indicators. Ultrasound-guided inactivation of myofascial trigger points (MTrPs) with dry needling and intradermal needling combined with press needling were applied on group D and pharmacotherapeutic only treatment on group P respectively. The VAS score <3 and/or the MPQ score <2 represents effective treatment. The VAS score >3 and/or the MPQ score >2 represents recurrent in follow-up study three months after the treatment.
Results:
After four weeks treatment, the effective rate of one month later of the group D was 92.9% and the effective rate of group P was 38.5%, respectively. The recurrent rate of group D was 7.1% and 34.6% for group P, respectively, for follow-up three months later. The satisfactory rate of group D was higher than that of group P.
Conclusion:
Ultrasound-guided dry needling and intradermal needling combined with press needling were more effective than only pharmacotherapeutic treatment for PHN mixed with MPS, with lower recurrent rate and higher patient's satisfactory rate.
... It has also been hypothesized that a potentially important mechanism responsible for the effects of dry needling could be that of anti-nociceptive effects of site-specific trigger point stimulation which may be mediated by segmental inhibitory effects evoked by selective stimulation of large myelinated fibers (Srbely, Dickey, Lee, and Lowerison, 2010). Hsieh, Chou, Joe, and Hong (2011) reported that the physiologic basis for the remote effects of dry needling may be related to an inactivation of myofascial trigger spots and activation of diffuse noxious inhibitory control induced by noxious stimulant applied to the painful region. Therefore, it was theorized that incorporating dry needling within the overall treatment of symptoms associated with CRS may allow for reduction in the use of prescription medications and more invasive procedures such as surgery. ...
Background:
Typically treated medically, chronic rhinosinusitis (CRS) is a prevalent condition characterized by multiple craniofacial symptoms, some of which may respond favorably to dry needling intervention.
Objective:
To describe the outcomes of a patient presenting with craniofacial pain and symptoms consistent with a diagnosis of CRS who was treated with dry needling. Case Description: A 41-year-old male, self-referred to physical therapy with a diagnosis of CRS, with a 20-year history of signs and symptoms associated with CRS, including craniofacial pain and headaches. The patient had been treated with multiple medication regimens over this time, including antihistamines, anti-inflammatories, decongestants, leukotriene inhibitors, and antibiotics; all of which provided only short-term relief. On initial examination, the patient was tender to palpation in multiple muscles of the head, neck, and face. Intervention consisted of dry needling to these muscular tender points once or twice weekly over 2 months.
Outcomes:
After 2 months of dry needling, the patient demonstrated clinically meaningful improvements in pain and quality of life, which included a decrease in both medication usage and the frequency of sinus infections.
Conclusion:
Although CRS is generally managed medically, we observed areas of muscular tenderness in this case, which were effectively managed with dry needling. Rehabilitative providers may consider screening CRS patients for muscular impairments that may be modifiable with dry needling. Further research should be performed to determine whether dry needling has a role in the management of CRS.
... Regarding the action mechanism of DN, the technique is believed to induce local changes in skeletal muscle 35 and pain inhibition at the level of the central nervous system via the periaqueductal grey matter. [35][36][37][38][39][40][41][42] Therefore, as is the case with botulinum toxin, 43 the analgesic effect of DN may involve both central and peripheral mechanisms. ...
Introduction
Non-pharmacological treatment of patients with headache, such as dry needling (DN), is associated with less morbidity and mortality and lower costs than pharmacological treatment. Some of these techniques are useful in clinical practice. The aim of this study was to review the level of evidence for DN in patients with headache.
Methods
We performed a systematic review of randomised clinical trials on headache and DN on the PubMed, Web of Science, Scopus, and PEDro databases. Methodological quality was evaluated with the Spanish version of the PEDro scale by 2 independent reviewers.
Results
Of a total of 136 studies, we selected 8 randomised clinical trials published between 1994 and 2019, including a total of 577 patients. Two studies evaluated patients with cervicogenic headache, 2 evaluated patients with tension-type headache, one study assessed patients with migraine, and the remaining 3 evaluated patients with mixed-type headache (tension-type headache/migraine). Quality ratings ranged from low (3/10) to high (7/10). The effectiveness of DN was similar to that of the other interventions. DN was associated with significant improvements in functional and sensory outcomes.
Conclusions
Dry needling should be considered for the treatment of headache, and may be applied either alone or in combination with pharmacological treatments.
... In their studies, Shah et al proved that with DDN, there is an immediate concentration in the area of neurotransmitters, such as calcitonin, as well as of various cytokines and interleukins, both outside and in cellular fluids [50,51]. Hsieh et al. confirmed that DDN models chemical mediators associated with pain and inflammation by increasing B-endorphins [52,53]. It is evident that DDN cannot be the only therapeutic option when treating chronic pain but must be accompanied by other therapeutic techniques [54,55], such as physical exercise, psychological treatment, and the treatment of sleep disorders [56,57]. ...
Background and Objectives: The objective of our clinical trial was to determine the effectiveness of the deep dry needling technique (DDN) (neuromuscular deprogramming) as a first step in the treatment of temporomandibular disorders. Methods and Materials: The double-blind randomized clinical trial comprised 36 patients meeting the inclusion criteria who had signed the corresponding informed consent form. The participants were randomly distributed into two groups, the Experimental group (Group E) and the Control group (Group C). Group E received bilateral DDN on the masseter muscle, while Group C received a simulation of the technique (PN). All the participants were evaluated three times: pre-needling, 10 min post-needling, and through a follow-up evaluation after 15 days. These evaluations included, among other tests: pain evaluation using the Visual Analog Scale (VAS) and bilateral muscle palpation with a pressure algometer; evaluation of the opening pattern and range of the mouth, articular sounds and dental occlusion using T-scans; and electromyography, which was used to evaluate the muscle tone of the masseter muscles, in order to control changes in mandibular position. Results: Digital control of occlusion using Tec-Scan (digital occlusion analysis) showed a significant reduction both in the time of posterior disclusion and in the time needed to reach maximum force in an MI position after needling the muscle, which demonstrated that there were variations in the static position and the trajectory of the jaw. The symmetry of the arch while opening and closing the mouth was recovered in a centric relation, with an increase in the opening range of the mouth after the procedure. Conclusions: facial pain is significantly reduced and is accompanied by a notable reduction in muscle activity after needling its trigger points.
... Myofascial trigger points have been have been found to include and spontaneous electrical activity (SEA) [38] and be characterized by localized stiff nodules [39,40]. Limited evidence, at least in animal models, suggests that dry needling into myofascial trigger points can reduce abnormal SEA [38,41]. This reduction of abnormal muscle activity at rest, may allow for more normal coordination of agonist and antagonist muscles and restoration of normal muscle function during routine functional activities [2]. ...
Background:
Dry needling treatment focuses on restoring normal muscle function in patients with musculoskeletal pain; however, little research has investigated this assertion. Shear wave elastography (SWE) allows quantification of individual muscle function by estimating both resting and contracted muscle stiffness.
Objective:
To compare the effects of dry needling to sham dry needling on lumbar muscle stiffness in individuals with low back pain (LBP) using SWE.
Methods:
Sixty participants with LBP were randomly allocated to receive one session of dry needling or sham dry needling treatment to the lumbar multifidus and erector spinae muscles on the most painful side and spinal level. Stiffness (shear modulus) of the lumbar multifidus and erector spinae muscles was assessed using SWE at rest and during submaximal contraction before treatment, immediately after treatment, and 1 week later. Treatment effects were estimated using linear mixed models.
Results:
After 1 week, resting erector spinae muscle stiffness was lower in individuals who received dry needling than those that received sham dry needling. All other between-groups differences in muscle stiffness were similar, but non-significant.
Conclusion:
Dry needling appears to reduce resting erector spinae muscle following treatment of patients with LBP. Therefore, providers should consider the use of dry needling when patients exhibit aberrant stiffness of the lumbar muscles.
... Eliciting a LTR is theorized to interrupt the mechanical, chemical, and electrical contributions to the MTrP (Hong and Simons, 1998). LTR during DN treatment has been correlated to a decrease or normalization in motor end plate activity (Abbaszadeh-Amirdehi et al., 2017;Chen et al., 2001;Chou et al., 2012;De Meulemeester et al., 2017;Hsieh et al., 2011). However, the mechanism of action is unknown, and the clinical importance of LTR in treatment is not clearly established in research. ...
Background
Biomechanical muscle stiffness has been linked to musculoskeletal disorders. Assessing changes in muscle stiffness following DN may help elucidate a physiologic mechanism of DN. This study characterizes the effects of dry needling (DN) to the infraspinatus, erector spinae, and gastrocnemius muscles on biomechanical muscle stiffness.
Method
60 healthy participants were randomized into infraspinatus, erector spinae, or gastrocnemius groups. One session of DN was applied to the muscle in standardized location. Stiffness was assessed using a MyotonPRO at baseline, immediately post DN, and 24 h later. The presence of a localized twitch response (LTR) during DN was used to subgroup participants.
Results
A statistically significant decrease in stiffness was observed in the gastrocnemius, the LTR gastrocnemius, and the LTR erector spinae group immediately following DN treatment. However, stiffness increased after 24 h. No significant change was found in the infraspinatus group.
Conclusions
DN may cause an immediate, yet transitory change in local muscle stiffness. It is unknown whether these effects are present in a symptomatic population or related to improvements in clinical outcomes. Future studies are necessary to determine if a decrease in biomechanical stiffness is related to improvement in symptomatic individuals.
... La irritación mecánica de la aguja sobre los nociceptores sensibilizados de los PGM genera repuestas de contracciones locales reflejas (CLR), moduladas por el sistema nervioso central. Estudios mediante microdiálisis han asociado la presencia de las CLR con la disminución de las concentraciones de bradiquinina, CGRP (Péptido relacionado con el gen de la calcitonina), sustancia P e interleuquina-1 en el PGM; como también la disminución de la actividad eléctrica espóntanea y el relajamiento de la banda tensa 3,4 . Desde los reportes iniciales de Hong C., la eficacia de la técnica dependería de la presencia de las CLR 5 . ...
... Needling applied to any part of the body may also show activity in the area where the main treatment is given (21). ...
Introduction:
The purpose of the current study was to investigate the antispastic efficacy of dry needling in combination with botulinum toxin-A injections.
Methods:
Thirty stroke patients with elbow flexor spasticity were randomised into two groups; the patients treated with botulinum toxin-A injections and exercise into the BTX-A group, and patients treated with botulinum toxin-A injections, exercise, and dry needling in the BTX-A+Dry needling group. Spasticity was evaluated using the modified Ashworth scale and modified Tardieu scale before treatment, immediately after treatment, the third day after treatment, second week after treatment and at the third month after treatment. The upper extremity motor function was evaluated using the Fugl-Meyer upper extremity motor function scale.
Results:
A statistically significant difference in all parameters was found after treatment in both groups compared to before treatment (p<0.05). In all evaluation parameters immediately after treatment, on the third day after treatment, the second week after treatment and the third month after treatment, a statistically significant difference in favour of the BTX-A+Dry needling group was achieved compared to before treatment (p<0.05).
Conclusion:
Dry needling combined with botulinum toxin-A injections performed over a total of four sessions with three-day intervals, contribute to the antispastic effect. Also combined therapy is more effective and provides longer-lasting results.
... Hsieh et al. [75] demonstrated that when LTRs were elicited by DDN to a MTrP region suppression of spontaneous electrical activity (SEA) occurred. ...
Several studies have shown that gastrocnemius is frequently injured in triathletes. The causes of these injuries are similar to those that cause the appearance of the myofascial pain syndrome (MPS). The ischemic compression technique (ICT) and deep dry needling (DDN) are considered two of the main MPS treatment methods in latent myofascial trigger points (MTrPs). In this study superficial electromyographic (EMG) activity in lateral and medial gastrocnemius of triathletes with latent MTrPs was measured before and immediately after either DDN or ICT treatment. Taking into account superficial EMG activity of lateral and medial gastrocnemius, the immediate effectiveness in latent MTrPs of both DDN and ICT was compared. A total of 34 triathletes was randomly divided in two groups. The first and second groups (n = 17 in each group) underwent only one session of DDN and ICT, respectively. EMG measurement of gastrocnemius was assessed before and immediately after treatment. Statistically significant differences (p = 0.037) were shown for a reduction of superficial EMG measurements differences (%) of the experimental group (DDN) with respect to the intervention group (ICT) at a speed of 1 m/s immediately after both interventions, although not at speeds of 1.5 m/s or 2.5 m/s. A statistically significant linear regression prediction model was shown for EMG outcome measurement differences at V1 (speed of 1 m/s) which was only predicted for the treatment group (R² = 0.129; β = 8.054; F = 4.734; p = 0.037) showing a reduction of this difference under DDN treatment. DDN administration requires experience and excellent anatomical knowledge. According to our findings immediately after treatment of latent MTrPs, DDN could be advisable for triathletes who train at a speed lower than 1 m/s, while ICT could be a more advisable technique than DDN for training or competitions at speeds greater than 1.5 m/s.
... Recent studies have also shown that DN achieves an increased activation of the sensory and motor areas in post-stroke [15,16]. Moreover, some experimental studies in animal models have shown that DN reduces the abnormal electromyographic (EMG) activity that is characteristic of MTrPs [17] and that an intact afferent pathway and normal spinal cord function are needed to evoke remote effects of dry needling on EMG endplate noise [18]. ...
This study aimed to determine the effect of one session of dry needling on the severity of tremor, motor function and skills, and quality of life of a 39-year-old woman with post-stroke tremor. Myofascial trigger points (MTrP) of the following muscles were treated: extensor digitorum, flexor digitorum superficialis and profundus, brachioradialis, short head of biceps brachii, long head of triceps brachii, mid deltoid, infraspinatus, teres minor, upper trapezius, and supraspinatus. Outcomes were assessed via (i) clinical scales (activity of daily living (ADL-T24), a visual analog scale (VAS), and the Archimedes spiral), (ii) a functional test (9-Hole Peg test), and (iii) biomechanical and neurophysiological measurements (inertial sensors, electromyography (EMG), and dynamometry). The subject showed a decrease in the severity of tremor during postural (72.7%) and functional (54%) tasks after treatment. EMG activity decreased after the session and returned to basal levels 4 days after. There was an improvement post-intervention (27.84 s) and 4 days after (32.43 s) in functionality and manual dexterity of the affected limb, measured with the 9-Hole Peg test, as well as in the patient’s hand and lateral pinch strength after the treatment (26.9% and 5%, respectively), that was maintained 4 days later (15.4% and 16.7%, respectively).
... The procedure for measuring EPN prevalence was conducted as described previously (Hsieh et al. 2011). After initial insertion, the needle was advanced very slowly under gentle rotation. ...
This study explores the involvement of substance P (SP) in the parabrachial nucleus (PBN) and central amygdaloid nucleus (CeA) in the nociception–emotion link and of rats with masticatory myofascial pain (MMP) induced by chronic tetanic eccentric muscle contraction. A total of 18 rats were randomly and equally assigned for MMP (MMP group) and sham-MMP induction (sMMP group). MMP was induced by electrical-stimulated repetitive tetanic eccentric contraction of the masseter muscle for 14 consecutive days. Myofascial trigger points in the masseter muscle were identified by palpable taut bands, increased prevalence of endplate noise (EPN), focal hypoechoic nodules on ultrasound and restricted jaw opening. All animals were killed for morphological and SP immunohistochemical analyses. Chronic tetanic eccentric contraction induced significantly thicker masseter muscle confirmed by hypoechogenicity, increased prevalence and amplitudes of EPN, and limited jaw opening. Immunohistochemically, the SP-like positive neurons increased significantly in PBN and CeA of the MMP group. Our results suggested that MMP increases the SP protein levels in PBN and CeA, which play important roles in MMP-mediated chronic pain processing as well as MMP-related emotional processes.
... The LTR has been described as a reflex contraction of the muscle fibres that form a taut band that can be elicited by inserting a needle into the band [40]. LTRs induced by intramuscular dry needling have been associated with the following changes within muscles: a reduction in excess electrical activity [41], a reduction in local excess levels of the neurotransmitters Substance P and calcitonin gene related peptide [42], and a reduction in mechanical hypersensitivity [43]. We did not document whether an LTR occurred with intramuscular needle insertions in the IMS group in this study. ...
Background
The insertion of filiform needles intramuscularly (a.k.a. intramuscular stimulation/dry needling) has been suggested as a possible treatment for various painful musculoskeletal conditions. Our aim was to answer the question, is intramuscular stimulation more effective than sham intramuscular stimulation/dry needling for the treatment of Achilles tendinopathy?
Methods
52 participants with persistent midportion Achilles tendinopathy began and 46 completed one of three treatment protocols which were randomly assigned: (G3) a 12-week rehabilitation program of progressive tendon loading plus intramuscular stimulation (n = 25), (G2) the same rehabilitation program but with sham intramuscular stimulation (n = 19), or (G1) a reference group of rehabilitation program alone (as an additional control) (n = 8). The a priori primary outcome measure was change in VISA-A score at 12 weeks–VISA-A was also measured at 6 weeks, and at 6 and 12 months. Secondary outcome measures include the proportion of patients who rated themselves as much or very much improved (%), dorsiflexion range of motion (degrees), and tendon thickness (mm).
Results
The study retention was 94% at 12 weeks and 88% at 1 year. VISA-A score improved in all three groups over time (p<0.0001), with no significant difference among the three groups in VISA-A score at the start of the study (mean ± SD: G3 59 ± 13, G2 57 ± 17, G1 56 ± 22), at 12 weeks (G3 76 ± 14, G2 76 ± 15, G1 82 ± 11) or at any other timepoint. The percentage of patients who rated themselves as much or very much improved (i.e. treatment success) was not different after 12 weeks (G3 70%, G2 89%, G1 86% p = 0.94), or at 26 (p = 0.62) or 52 weeks (p = 0.71). No clinically significant effects of intervention group were observed in any of the secondary outcome measures.
Conclusion
The addition of intramuscular stimulation to standard rehabilitation for Achilles tendinopathy did not result in any improvement over the expected clinical benefit achieved with exercise-based rehabilitation alone.
... A recent study established that endplate noise amplitude changes were significantly correlated with changes in TrP irritability. The changes were found to be useful as an indicator of the irritability of neural pathways and mechanisms in the TrS region and for remote effects of DN (Hsieh et al., 2011). ...
We are sad to report that following this issue, Dr. Li-Wei Chou will no longer be able to contribute to this quarterly literature overview. Unfortunately, his work responsibilities have increased to such an extent that they need to take priority. On behalf of the team, we would like to thank Dr. Chou for his thoughtful and balanced reviews during the past few years. Not only were we able to include an occasional Chinese-language study, he also was able to assist us in interpreting more complex medical studies. Li-Wei, we wish you all the best professionally and personally, and of course, we cannot wait until our paths will cross again sometime in the future!
You may have noted that this overview article was missing from the January 2020 issue of the journal due to an administrative mix up. With the current issue we aimed to catch up and therefore, you will find a greater number of reviewed articles than usual. It becomes increasingly challenging to cover the wide range of the published myofascial pain and trigger point (TrP) literature just due to its volume. In this edition, we included 10 basic research articles, 4 reviews, 14 articles on dry needling (DN), acupuncture, and injections, 3 on manual therapies, and 4 on other clinical approaches.
... En relación con el mecanismo de acción de la PS, se relaciona con cambios locales sobre el músculo esquelético 35 , así como con efectos inhibitorios del dolor a nivel central a través de la sustancia gris periacueductal [35][36][37][38][39][40][41][42] . Por ello, al igual que en la toxina botulínica 43 , es posible que en sus mecanismos de analgesia participen mecanismos a nivel periférico y central. ...
Introduction:
Non-pharmacological treatment of patients with headache, such as dry needling (DN), is associated with less morbidity and mortality and lower costs than pharmacological treatment. Some of these techniques are useful in clinical practice. The aim of this study was to review the level of evidence for DN in patients with headache.
Methods:
We performed a systematic review of randomised clinical trials on headache and DN on the PubMed, Web of Science, Scopus, and PEDro databases. Methodological quality was evaluated with the Spanish version of the PEDro scale by 2 independent reviewers.
Results:
Of a total of 136 studies, we selected 8 randomised clinical trials published between 1994 and 2019, including a total of 577 patients. Two studies evaluated patients with cervicogenic headache, 2 evaluated patients with tension-type headache, one study assessed patients with migraine, and the remaining 3 evaluated patients with mixed-type headache (tension-type headache/migraine). Quality ratings ranged from low (3/10) to high (7/10). The effectiveness of DN was similar to that of the other interventions. DN was associated with significant improvements in functional and sensory outcomes.
Conclusions:
Dry needling should be considered for the treatment of headache, and may be applied either alone or in combination with pharmacological treatments.
INTRODUCTION
Low back pain (LBP) is defined as a painful condition, being a major public health problem in industrialized countries that causes distress, suffering and work absences. Due to LBP is considered a common pathology, a complete treatment represents a real challenge for society and healthcare systems (1). In Europe, the direct and indirect costs of LBP account for between 1.7 and 2.1% of the yearly gross domestic product (2). In this context, it´s estimated that 80% of the adult population will
Study design
A triple-blind, two-group parallel randomized trial was carried out in individuals with mechanical chronic non-specific low back pain, following the principles of the Declaration of Helsinki. This study was elaborated following the Consolidated Standards of Reporting Trials (CONSORT) (22) and was approved by the Research Ethics Committee of the (CEIM/HU2019/18) and registered (ClinicalTrials.gov Identifier: NCT04090502). The triple-blind design prevented both the participants, the examiner, and
Baseline Data
A total of 50 (27 female) participants were included in the study (4 volunteers were excluded due to diagnosis of specific low back pain) and divided into two groups, CG (n = 25; 10 female) and EG (n = 25; 17 male). Table 1 shows the clinical and demographic characteristic of the participants of both groups.
No significant differences between groups were observed at the baseline measures. Significant differences were observed in the group-by-time interaction in the VAS F(2, 92)=5.603, p=0.005)
DISCUSSION
Based on the findings of our study, it was observed that pain intensity, disability and AKE showed consistent improvements across all sites treated with active MTrPs of the hamstring muscles, irrespective of whether it hyperalgesic and non-hyperalgesic area.
In relation to pain intensity, our data reveals that patients who underwent DN in the hyperalgesic area experienced a statistically significant reduction in low back pain, as assessed by VAS, one and three-months after treatment. These
CONCLUSIONS
DN proves to be an effective technique for decreasing pain intensity, alleviating disability, and enhancing AKE in individuals suffering from chronic non-specific LBP and hamstring tightness, particularly when targeting the hyperalgesic region within the hamstring muscles
Objective:
The purpose of this study was to evaluate the effect of a single treatment vs serial dry needling (DN) treatments of the fibularis longus on individuals with chronic ankle instability and to determine the longevity of any effect found.
Methods:
Thirty-five adults with chronic ankle instability (24.17 ± 7.01 years, 167.67 ± 9.15 cm, 74.90 ± 13.23 kg) volunteered for a university laboratory repeated-measures study. All participants completed patient-reported outcomes and were objectively tested using the Star Excursion Balance Test (SEBT), threshold to detect passive motion (TTDPM) measurements, and single limb time-to-boundary measurements. Participants received DN treatment to the fibularis longus once weekly for 4 weeks on the affected lower extremity by a single physical therapist. Data were collected 5 times: baseline 1 week before initial treatment (T0), pre-treatment (T1A), immediately after the first treatment (T1B), after 4 weekly treatments (T2), and 4 weeks after the cessation of treatment (T3).
Results:
Significant improvements were found for clinician-oriented (SEBT-Composite P < .001; SEBT-Posteromedial P = .024; SEBT-Posterolateral P < .001; TTDPM-Inversion P = .042) and patient-oriented outcome measures (Foot and Ankle Ability Measure-Activities of Daily Living P < .001; Foot and Ankle Ability Measure-Sport P = .001; Fear Avoidance Belief Questionnaire P = .021) following a single DN treatment. Compounding effects from additional treatments exhibited improvement of TTDPM (T1B to T2). No significant losses were noted 4 weeks after cessation of treatment (T2 to T3).
Conclusion:
For the participants in this study, outcomes improved immediately following the first DN treatment. This improvement was sustained but not further improved with subsequent treatments.
The purpose was to determine the efficacy of deep dry needling (DDN) applied on an active myofascial trigger point (MTrP) versus a latent-MTrP versus a non-MTrP location, on pain reduction and cervical disability, in patients with chronic neck pain. A randomized, double-blind clinical trial design was used. A sample of 65 patients was divided into non-MTrP-DDN, active-MTrP-DDN and latent-MTrP-DDN groups. The visual analog scale (VAS), reproduction of the patient’s pain, number of local twitch responses, pressure pain threshold (PPT) and Neck Disability Index (NDI) were assessed before, during and after the intervention and up to 1 month post-intervention. The active-MTrP-DDN-group reduced pain intensity more than non-MTrP-DDN-group after a week and a month (P < 0.01), as well as showing the greatest improvement in tibialis muscle PPT. The treatment of both Active and Latent MTrPs was associated with the reproduction of the patient’s pain. The application of DDN on an active-MTrP in the upper trapezius muscle shows greater improvements in pain intensity after 1 week and 1 month post-intervention, compared to DDN applied in latent-MTrPs or outside of MTrPs in patients with neck pain.
Objective:
Dry needling is a commonly used treatment technique for myofascial pain syndromes, such as trapezius myalgia. Despite the shown positive clinical effects on pain, the underlying mechanisms of action, such as the effect on muscle electrophysiology, remain unclear. The aim of this study was to investigate the effect of dry needling, compared with sham needling, in the upper trapezius muscle on surface electromyography activity and the relation with pain in office workers with trapezius myalgia.
Design:
For this experimental randomized controlled trial, 43 office workers with work-related trapezius myalgia were included. Surface electromyography activity was measured before and after a pain-provoking computer task and immediately after, 15, and 30 mins after treatment with dry or sham needling. Pain scores were evaluated at the same time points as well as 1, 2, and 7 days after treatment.
Results:
No significant differences in surface electromyography activity between dry needling and sham needling were found. Significant positive low to moderate Spearman correlations were found between surface electromyography activity and pain levels after dry needling treatment.
Conclusions:
This study shows no immediate effects of dry needling on the electrophysiology of the upper trapezius muscle, compared with sham needling.
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 minutes. 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 many musculoskeletal conditions. Insertion of multiple needles for typically 20-30 minute 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.
Muscles’ trigger points can induce scapular dyskinesia (SD) which interferes with overhead athletes' professional training. We aimed to evaluate effects of dry needling (DN) alone and plus manual therapy (MT) on pain and function of overhead athletes with SD. 40 overhead athletes (15male, 25female) aged 18-45 with at least 3points Numeric Rating Scale (NRS) pain intensity during training were recruited and randomly allocated to the treatment group: MT followed by DN on trigger points of Subscapularis, Pectoralis minor, Serratus anterior, upper and lower Trapezius muscles; or the control group: MT alone. The effect of shoulder trigger points DN plus MT with MT alone on pain, function, Pain Pressure Threshold (PPT) and SD in athletes with SD were compared. Both the examiner and the therapist were blinded to group assignment. both groups were analyzed. Pain, disability and SD were improved in treatment group (P<.05). On the other hand, when only MT was applied, despite reduction in pain and disability (P<.001), scapular slide only improved in hands on waist position. Comparing the differences between groups showed a substantial reduction in pain (P<.001) and disability (P=.02) with significant improvement in scapular dyskinesia in treatment group (P=.02). Moreover, PPT significantly increased in the control group (P=.004). No adverse effects reported by the participants during this study. DN is an easy and applicable method that can synergistically reduce pain, disability and dyskinesia when it is combined with manual techniques to treat shoulder dysfunctions.
Objective
The purpose of this study was to compare postural control and neurophysiologic components of balance after dry needling of the fibularis longus between individuals with chronic ankle instability (CAI) and a healthy control group.
Methods
This quasi-experimental university-laboratory study included 50 adult volunteers—25 with CAI (16 female, 9 male; age: 26 ± 9.42 years; height: 173.12 ± 9.85 cm; weight: 79.27 ± 18 kg) and 25 healthy controls (15 female, 10 male; age: 25.8 ± 5.45 years; height: 169.47 ± 9.43 cm; weight: 68.47 ± 13 kg). Participants completed the Star Excursion Balance Test (SEBT), single-leg balance, and assessment of spinal reflex excitability before and after a single treatment of dry needling to the fibularis longus. The anterior, posterolateral, and posteromedial directions of the SEBT were randomized, and reach distances were normalized to a percentage of leg length. A composite SEBT score was calculated by averaging the normalized scores. Postural control was assessed in single-limb stance on a force plate through time-to-boundary measurements in eyes-open and eyes-closed conditions. Fibularis longus and soleus spinal reflexes were obtained by providing electrical stimulation to the common fibular and tibial nerves with participants lying prone. A Group × Time analysis examined changes in performance, and effect sizes were calculated to assess significance.
Results
Significant group × time interactions were identified for composite (P = .006) and posteromedial (P = .017) SEBT scores. Significant time effects for all directions of the SEBT, time to boundary with eyes open, and the mediolateral direction with eyes closed indicate improved postural control following treatment (P < .008). Within-group effect sizes for significant time effects ranged from small to large, indicating potential clinical utility.
Conclusion
Dry needling demonstrated immediate short-term improvement in measures of static and postural control in individuals with CAI as well as healthy controls.
The primary objective of this research paper is design and nonlinear finite element analysis of micro-lattice of Ti-6Al-4V implants using the Bauschinger effect. Micro-lattice cellular Ti-6Al-4V structures are commonly used for orthopedic application with an organized porosity and pore sizes appropriate for tissue ingrowth and organic process. In this research paper CAD model of different unit lattice structures with design variables such as strut length, strut cross-section, and pore size using Intra-Lattice software were designed. Intra-Lattice software is a parametric lattice demonstrating tool and is developed based on Grasshopper, a graphical algorithm editor for Rhino CAD software. In this study, three different unit cells are presented including a Grid (simple cubic), Star (body-centered cubic), and Tesseract (hypercubic) structure. The finite element analysis (FEA) technique is presented to analyze the mechanical properties of these three types of lattices-based cellular structure. For FE modeling, beam elements have been used to model the micro-lattice structures under different loading conditions (i.e. tension and compressive). The FE simulations were carried to predict the functional effectiveness and
load-bearing effectiveness for the above three unit cells. In the last phase of this investigation, the unit cell topology was improved to increase the stiffness and yield stress under loading conditions. Finite Element Simulations demonstrate that the
stiffness and yield strength can be enhanced by changing the unit cell geometry. The results of the above investigation will then be applied to patient-specific implants.
The primary objective of this research paper is design and nonlinear finite element analysis of micro-lattice of Ti-6Al-4V implants using the Bauschinger effect. Micro-lattice cellular Ti-6Al-4V structures are commonly used for orthopedic applications with an organized porosity and pore sizes appropriate for tissue ingrowth and organic process. In this research paper CAD model of different unit lattice structures with design variables such as strut length, strut cross-section, and pore size using Intra-Lattice software were designed. Intra-Lattice software is a parametric lattice demonstrating tool and is
developed based on Grasshopper, a graphical algorithm editor for Rhino CAD software. In this study, three different unit cells are presented including a Grid (simple cubic), Star (body-centered cubic), and Tesseract (hypercubic) structure. The finite element analysis (FEA) technique is presented to analyze the mechanical properties of these three types of lattices-based cellular structure. For FE modeling, beam elements have been used to model the micro-lattice structures under different loading conditions (i.e. tension and compressive). The FE simulations were carried to predict the functional effectiveness and
load-bearing effectiveness for the above three unit cells. In the last phase of this investigation, the unit cell topology was improved to increase the stiffness and yield stress under loading conditions. Finite Element Simulations demonstrate that the
stiffness and yield strength can be enhanced by changing the unit cell geometry. The results of the above investigation will then be applied to patient-specific implants.
Introduction:
Myofascial Pain Syndrome (MPS) is one of the most common conditions of chronic musculoskeletal pain, yet its mechanisms are still poorly understood. Delayed Onset Muscle Soreness (DOMS) is also a regional pain syndrome that has clinical similarities to MPS, but has been better investigated. Emerging research suggests that DOMS may be a valid experimental model for studying MPS; however, a comparison of the similarities and differences of these two conditions has previously not been performed. Herein, we aimed to identify the similarities and differences in the clinical features and biomarkers between DOMS and MPS in order to better define MPS and identify future areas of (DOMS-informed) MPS research.
Evidence acquisition:
In order to identify similarities and differences in the clinical manifestation and biomarkers of DOMS and MPS, scoping literature searches were performed using Medline (1965-2019), Embase (1966-2019) and Central (1966 - 2019) databases. 53 full text articles were reviewed out of the 2836 articles retrieved in the search.
Evidence synthesis:
A scoping review of the literature demonstrated that DOMS and MPS similarly present as conditions of musculoskeletal pain that are associated with decreased strength and limited range of motion. However, while taut bands and discrete tender spots were described in DOMS, none of the studies reviewed have characterized whether these tender points represent the classic myofascial trigger point phenomenon observed in MPS. Certain systemic circulation biomarkers, including inflammatory cytokines and growth factors, were commonly elevated in MPS and DOMS; further research is needed to determine if other biomarkers that are currently characterized in DOMS are useful to enhance the clinical evaluation of MPS.
Conclusions:
DOMS and MPS share clinical and biomarker similarities suggesting that DOMS may be a useful model for studying MPS.
Objective: To test the hypothesis that dry needle stimulation of a myofascial trigger point (sensitive locus) evokes segmen-tal anti-nociceptive effects. Design: Double-blind randomized controlled trial. Subjects: Forty subjects (21 males, 19 females). Methods: Test subjects received intramuscular dry needle puncture to a right supraspinatus trigger point (C 4,5); controls received sham intramuscular dry needle puncture. Pain pressure threshold (PPT) readings were recorded from right infraspinatus (C 5,6) and right gluteus medius (L 4,5 S 1) trigger points at 0 (pre-needling baseline), 1, 3, 5, 10 and 15 min post-needling and normalized to baseline values. The supraspinatus and infraspinatus trigger points are neuro-logically linked at C 5 ; the supraspinatus and gluteus medius are segmentally unrelated. The difference between the infra-spinatus and gluteus medius PPT values (PPT seg) represents a direct measure of the segmental anti-nociceptive effects acting at the infraspinatus trigger point. Results: Significant increases in PPT seg were observed in test subjects at 3 (p = 0.002) and 5 (p = 0.015) min post-needling, compared with controls. Conclusion: One intervention of dry needle stimulation to a single trigger point (sensitive locus) evokes short-term seg-mental anti-nociceptive effects. These results suggest that trigger point (sensitive locus) stimulation may evoke anti-nociceptive effects by modulating segmental mechanisms, which may be an important consideration in the management of myofascial pain.
To test the hypothesis that dry needle stimulation of a myofascial trigger point (sensitive locus) evokes segmental anti-nociceptive effects.
Double-blind randomized controlled trial.
Forty subjects (21 males, 19 females).
Test subjects received intramuscular dry needle puncture to a right supraspinatus trigger point (C4,5); controls received sham intramuscular dry needle puncture. Pain pressure threshold (PPT) readings were recorded from right infraspinatus (C5,6) and right gluteus medius (L4,5S1) trigger points at 0 (pre-needling baseline), 1, 3, 5, 10 and 15 min post-needling and normalized to baseline values. The supraspinatus and infraspinatus trigger points are neurologically linked at C5; the supraspinatus and gluteus medius are segmentally unrelated. The difference between the infraspinatus and gluteus medius PPT values (PPTseg) represents a direct measure of the segmental anti-nociceptive effects acting at the infraspinatus trigger point.
Significant increases in PPTseg were observed in test subjects at 3 (p = 0.002) and 5 (p = 0.015) min post-needling, compared with controls.
One intervention of dry needle stimulation to a single trigger point (sensitive locus) evokes short-term segmental anti-nociceptive effects. These results suggest that trigger point (sensitive locus) stimulation may evoke anti-nociceptive effects by modulating segmental mechanisms, which may be an important consideration in the management of myofascial pain.
To investigate the effects of dry needling over active trigger points (TrPs) in the masseter muscle in patients with temporomandibular disorders (TMD).
Twelve females, aged 20 to 41 years old (mean = 25, standard deviation +/- 6 years) diagnosed with myofascial TMD were recruited. Each patient attended two treatment sessions on two separate days and received one intervention assigned in a random fashion, at each visit: deep dry needling (experimental) or sham dry needling (placebo) at the most painful point on the masseter muscle TrP. Pressure pain threshold (PPT) over the masseter muscle TrP and the mandibular condyle and pain-free active jaw opening were assessed pre- and 5 minutes postintervention by an examiner blinded to the treatment allocation of the subject. A two-way repeated-measures analysis of variance (ANOVA) with intervention as the between-subjects variable and time as the within-subjects variable was used to examine the effects of the intervention.
The ANOVA detected a significant interaction between intervention and time for PPT levels in the masseter muscle (F = 62.5; P < .001) and condyle (F = 50.4; P < .001), and pain-free active mouth opening (F = 34.9; P < .001). Subjects showed greater improvements in all the outcomes when receiving the deep dry needling compared to the sham dry needling (P < .001).
The application of dry needling into active TrPs in the masseter muscle induced significant increases in PPT levels and maximal jaw opening when compared to the sham dry needling in patients with myofascial TMD.
"Juci", one of the traditional acupuncture techniques, means contralateral acupuncture; i.e., implanting a needle into an acupoint to treat a given disease or disorder, but on the side of the body opposite to the diseased side. The aim of this study was: (1) to assess acupuncture effects on formalin-induced nociceptive behavior in the orofacial region in the rat, and (2) to evaluate the efficacy of Juci in the orofacial formalin test.
Forty-four adult male Wistar rats were used in the present study. A 1.0% formalin solution (25 microl s.c., diluted in saline) was injected into the right upper lip. The rats were randomly assigned to five groups. (1) The control group (n = 9), which received formalin injection without acupuncture pretreatment; (2) the ipsilateral Ho-ku (see note below) acupuncture group (n = 10); (3) the contralateral Ho-ku acupuncture group (n = 11); (4) the acupuncture plus naloxone group (n = 9), where intraperitoneal naloxone (1.0 mgxkg(-1)) was injected immediately before acupuncture pretreatment; and (5) the sham acupuncture group (n = 5). "Ho-ku" is the term used for the "Large Intestine 4" acupoint, located between the first and second metacarpal bones.
The injection of formalin produced the characteristic biphasic behavioral response. Acupuncture significantly inhibited the response in the early and late phases. Naloxone significantly reversed these effects. There were no statistically significant differences between the ipsilateral and Juci acupuncture groups. Sham acupuncture did not exert any significant effect on the formalin-induced behavior.
Our results showed that the degree of effectiveness of Juci was similar to that of the ipsilateral acupuncture technique. Therefore, the Juci technique is also useful for the treatment of orofacial pain.
To investigate the effects of electro-acupuncture (EA) treatment on regions remote from the application, we measured cellular, enzymatic, and transcriptional activities in various internal tissues of healthy rats. The EA was applied to the well-identified acupoint ST36 of the leg. After application, we measured the activity of natural killer cells in the spleen, gene expression in the hypothalamus, and the activities of antioxidative enzymes in the hypothalamus, liver and red blood cells. The EA treatment increased natural killer cell activity in the spleen by approximately 44%. It also induced genes related to pain, including 5-Hydroxytryptamine (serotonin) receptor 3a (Htr3a) and Endothelin receptor type B (Ednrb) in the hypothalamus, and increased the activity of superoxide dismutase in the hypothalamus, liver, and red blood cells. These findings indicate that EA mediates its effects through changes in cellular activity, gene expression, and enzymatic activity in multiple remote tissues. The sum of these alterations may explain the beneficial effects of EA.
Objective: To determine whether the spontaneous electrical activity observed in trigger spots of rabbit skeletal muscle is restricted only to trigger spots, and to compare that electrical activity to descriptions of potentials from neuromuscular junctions of rabbits from trigger points in human subjects. Methods: Fourteen paired examinations of trigger spots and control sites were performed on surgically exposed biceps femoris muscles in six anesthetized New Zealand Albino rabbits. Each examination involved 24 needle advances in three tracks [eight advances per track]. The trigger spot was identified as the location along a palpable taut band of muscle where snapping palpitation elicited the largest rabbit localized twitch response. The number of active loci [minute regions from which spontaneous potentials were recorded electromyographically] found in trigger spots was compared to the number of active loci found in control sites [where no taut band was identified by palpation]. Results: Spontaneous electrical activity was observed at 70 loci in trigger spots and at 15 loci in control sites [a significant difference, P < 0.01 using the Fischer exact test]. In addition to low-amplitude uninterrupted spontaneous electrical activity, the recordings occasionally showed high-amplitude intermittent spikes, as described by others. Conclusion: These results suggest that the observed spontaneous electrical activity has an important relation to the pathophysiology responsible for trigger-spot phenomena. The potentials observed at trigger spots appear to be the same in character as the potentials identified at neuromuscular junctions and at human trigger points. Active loci of trigger spots and control sites should be examined for pathophysiological differences.
Objectives: The purpose of this article is to review the previously published data on myofascial trigger point injection and to present a proposed technique of myofascial trigger point [TrP] injection modified from tha described by Drs. Travell and Simons. Findings: Trigger point injection is an effective and valuable procedure to inactivate an active TrP, and subsequently relieve the pain and tightness of the muscle involved in myofascial pain syndrome. It is essential to elicit a local twitch response [LTR] during TrP injection to obtain the best results of immediate relief of pain. LTR is a brisk twitching of the muscle fibers of the taut band during mechanical stimulation [including needling] on the most sensitive site, the TrP region. Sometimes, other remote TrPs can also be inactivated if the "key TrP" is appropriately selected for injection based on skillfull clinical judgement. The trigger point injections are indicated for quick relief of acute, subacute, or chronic myofascial pain, for substitution of narcotic medicine, for restoration of functional impairment due to myofascial trigger points, or for supplementary therapy of chronic myofascial pain to facilitate its recovery. It is generally recommended to use 0.5% of procaine or lidocaine at a dose of 0.5-1.0 cc per TrP region for TrP injection. The proposed technique of TrP injection includes identification of the taut band containing the active TrP, skin preparation with sterile technique, rapid needle insertion into the multiple sites of a TrP region, injection of local anesthetic only if LTR is elicited, hemostatis, stretching and spray, and appropriate post-injection cares including cold or hot pack application, therapeutic exercise, therapeutic massage, and home program. The frequency and total number of injections should be determined based on clinical judgement. Some complications, such as muscle fiber damage, excessive bleeding, infection, syncope, or internal organ injury, may occur, but are usually preventable with careful and skillful injection technique. Conclusions: A technique of trigger point injection is proposed. Other than the traditional injection method, local twitch responses should be elicited as many times as possible during injection. The insertion of the needle should be quick to minimize muscle fiber damage. This technique is usually very effective to obtain immediate and complete pain relief.
Objective: This study was designed to investigate the electromyographic characteristics of the Rabbit Localized Twitch Response [R-LTR], a brisk contraction of a certain group of rabbit skeletal muscle fibers [a responsive band] elicited by mechanical stimulation of the most pressure-sensitive site [TrS]. Methods: In this study, R-LTRs were electromyographically investigated on 9 rabbits [ages 2-12 months]. Each animal was anesthetized in a way that preserved most peripheral reflexes mediated by the central nervous system. R-LTRs were elicited by one of three different mechanical stimuli; manual-probe stimulus [similar to snapping palpation], mechanical-tap stimulus [delivered by a solenoid driven blunt metal probe], or needle insertion using a solenoid-driven needle. Results: R-LTRs were best recorded from the responsive band [but not the other spots in the responsive band, or any spot in the non-responsive fibers] was mechanically stimulated. Responses to snapping stimulation were longer in duration than those to mechanical tap stimulation, which in turn were longer than R-LTRs produced by needle stimulation. This observation supports the impression that one trigger spot of the rabbit may contain multiple loci of hypersensitivity. The nearly complete loss of R-LTRs following lidocaine block or transection of the motor nerve indicates that propagation of the R-LTR is primarily via a central nervous system reflex rather than exclusively via director muscle-fiber transmission. Conclusion: The rabbit localized twitch responses [R-LTRs] show several similarities to and no incompatibility with, the human local twitch response [LTR]. The rabbit shows promise as an animal model for study of LTRs and possibly of taut bands and TrPs that are characteristic of myofascial pain syndrome.
A review is made of recent studies on myofascial trigger points (MTrP) and their mechanism is discussed. Clinical and basic science studies have shown that there are multiple MTrP loci in a MTrP region. A MTrP locus contains a sensory component (sensitive locus) and a motor component (active locus). A sensitive locus is a point from which tenderness or pain, referred pain, and local twitch response can be elicited by mechanical stimulation. Sensitive loci (probably sensitised nociceptors) are widely distributed in the whole muscle, but are concentrated in the endplate zone. An active locus is a site from which spontaneous electrical activity can be recorded. Active loci appear to be dysfunctional endplates since spontaneous electrical activity is essentially the same as the electrical activity reported by neurophysiologists as that recorded from an abnormal endplate. A MTrP is always found in a taut band which is histologically related to contraction knots caused by excessive release of acetylcholine in abnormal endplates. Both referred pain and local twitch response are mediated through spinal cord mechanisms, as demonstrated in both human and animal studies.
The pathogenesis of MTrPs appears to be related to integration in the spinal cord of response to the disturbance of nerve endings and abnormal contractile mechanism at multiple dysfunctional endplates. There are many similarities between MTrPs and acupuncture points including their location and distribution, pain and referred pain patterns, local twitch responses (de qi), and possible spinal cord mechanism.
Myofascial trigger point (MTrP) is the major cause of myofascial pain syndrome. On the basis of recent studies on both human and animal subjects, the pathophysiology of MTrP has been better understood. There are multiple sensitive loci in an MTrP region that are sensitized nociceptors in the vicinity of dysfunctional endplates. The irritability of an MTrP depends on the amount of sensitized nociceptors in the MTrP region. Stimulation of the sensitive locus can cause pain, referred pain, and local twitch response. As a result of excessive leakage of acetylcholine in the dysfunctional endplate, sarcomeres in this endplate region become shortened, which can cause taut band formation and elicit an energy crisis that perpetuates the vicious cycle train of "excessive acetylcholine leakage"-"increase of tension in taut band"-"release of sensitizing painful substance." Interruption of this cycle can inactivate the MTrP. However, the most important strategy to treat myofascial pain is to identify and treat the underlying etiological lesion that activates the MTrP. Effective methods that can inactivate an MTrP include stretching, deep-pressure massage, laser therapy, and needling.
Objectives: To assess the changes in the prevalence and the morphology of spontaneous electrical activity [SEA] after spinal cord transection and subsequent nerve transection in an animal model of myofascial trigger point [MTrP] in order to further understand the mechanism of MTrP. Spontaneous electrical activity can be recorded from a minute locus in a human MTrP region, and also from that in the myofascial trigger spot [similar to human MTrP] of rabbit skeletal muscle. Methods: Four adult albino rabbits were studied for the prevalence and amplitude changes of SEA in the biceps femoris muscle before and after spinal cord transection at the level of T4 or T5, and also after subsequent transection of the sciatic nerve. Results: There was no significant change in the prevalence and amplitude of SEA up to 60 minutes after spinal cord transection and 30 minutes after subsequent nerve transection. Conclusions: The occurrence of SEA is not mediated through the spinal or supraspinal circuits. The origin of SEA appears to be a local motor endplate phenomenon.
Objective: This case study was conducted to investigate the role of myofascial trigger points of the pectoralis minor muscle in producing symptoms following whiplash injury. Methods: To be included in this retrospective study, patents were required to exhibit an active myofascial trigger point in at least one pectoralis minor muscle and should not have received therapy directed at myofascial pain syndrome prior to evaluation by the authors. other exclusions included bone fracture, cervical radiculopathy/myelopathy, and brain injury. Treatment without controls of the 37 patients included physical therapy measures selected to relieve the myofascial pain syndrome. Patients whose symptoms proved resistant to physical therapy received two or more courses of therapy and injection of their trigger points. By assessment that was not blinded as to intervention, a successful outcome lasting at least 6 months depended upon the subject being pain free or sufficiently improved with a continuing home self-stretch program that normal activities could be resumed. Results: A complex of clinical characteristics common to all patients included pain at the neck radiating to the upper limb, and a positive hyperabduction maneuver. Together, these findings fit the diagnosis of a pectoralis minor myofascial pain syndrome. The patients divided conveniently into three groups based on the time required to reach symptomatic relief [<6 months, N = 12; 6-18 months, N = 13; and >18 months, N = 5]. The rate of progress was not related to age, sex, direction of impact, delayed onset of symptoms, or the location of symptoms. Variables which correlated with delayed recovery included a long delay before initiating therapy, a large number of trigger points, a bulging cervical disc by MRI, nerve conduction velocity evidence for compression neuropathy of the ulnar component of the brachial plexus where it lies deep to the pectoralis minor tendon, and reinjury. Conclusion: Prompt recognition and treatment of a pectoralis minor myofascial syndrome caused by whiplash injury should reduce suffering, lower medical costs, and reduce loss of productivity.
Objective: This study investigated spinal cord mediation of rabbit localized twitch responses [R-LTRs] by transection of the spinal cord and later of the peripheral nerve. Rabbit localized twitch response [R-LTR] is a brisk contraction of a group of rabbit skeletal muscle fibers which is most responsive to mechanical stimulation of the pressure-sensitive site, the trigger spot [TrS]. An R-LTR is analogous to a local twitch response of a human taut band, and a TrS is analogous to a human myofascial trigger point [TrP]. Methods: The electromyographic [EMG] activity of R-LTRs was recorded for the biceps femoris muscle of 5 rabbits [ages: 2-3 months]. Each animal was anesthetized in a way that preserved most peripheral reflexes. R-LTRs were elicited by mechanical-tap stimuli [delivered by a solenoid-driven blunt metal probe] to the TrS. The percentage of occurence of R-LTRs and the changes in maximal amplitude and duration of EMG activity of R-LTRs [before the spinal cord transection at T4, T5, or T6, and then 5 minutes, 10 minutes, 30 minutes, 60 minutes, 120 minutes and 150 minutes after spinal cord transection] were analyzed. In addition, EMG activity was recorded immediately, 5 minutes, 30 minutes, and 60 minutes after further transection of the sciatic nerve. Results: Immediately after spinal cord transection, R-LTRs were unobtainable and the EMG activity had completely disappeared. There was evidence of partial recovery of the R-LTR at 5-10 minutes; there was nearly complete recovery by 2.5 hours after spinal cord transection. Additional transection of the muscle nerve completely abolished R-LTRs which lasted for the duration of the experiment. Conclusion: R-LTRs are mainly mediated through the spinal cord, and supraspinal structures are not essential.
SUMMARY Background: The most important strategy in myofascial pain syndrome therapy is to identify the etiological lesion that causes the activation of myofascial trigger points [s] and to treat the underlying pathology. If the underlying etiological lesion is not appropriately treated, the TrP can only be inactivated temporarily, and never completely. Findings: Generally, active TrPs should be treated conservatively with non-invasive techniques such as physical therapy prior to the consideration of aggressive therapy with invasive techniques such as needling and injection. This principle should also be observed when treating the underlying etiological lesions. Conservative therapy, such as manual therapy combined with thermotherapy and electrotherapy, can usually inactivate painful TrPs. Other situations, however, might necessitate dry needling or TrP injection: 1. persistent pain or discomfort after complete elimination of the underlying pathological lesion responsible for TrP activation, 2. poor response to conservative therapy, 3. intolerable pain, 4. deep location of a TrP, rendering it inaccessible by conservative manual therapy, 5. inadequate time to accept the time-consuming conservative therapy, or 6. personal preference. When treating myofascial pain syndrome, it is also important to eliminate any perpetuating factors that may cause persistent chronic pain, and to provide adequate education and home programs to patients, so that recurrent or chronic pain can be avoided. Conclusions: Myofascial pain should be appropriately treated to inactivate TrPs completely and to avoid recurrence permanently.
Our recent studies of the neural mechanisms of the reflex effects on visceral functions of acupuncture-like stimulation applied to the skin and underlying muscle by twisting a needle in anesthetized rats are reviewed. Gastric motility was inhibited by acupuncture-like stimulation of the abdominal areas and facilitated by limb stimulation. The rhythmic micturition contractions of the urinary bladder were inhibited by stimulation of the perineal area. Responses of sympathoadrenal medullary function to acupuncture-like stimulation were inconsistent. Blood pressure responses were inconsistent, but in a deep anesthetized condition, acupuncture-like stimulation applied to the hindlimb muscles caused a decrease in blood pressure. Each of the responses observed was a reflex response whose afferent pathways consisted of cutaneous and muscle afferent nerves and efferent pathways consisted of the autonomic efferent nerves. The reflex center was in the central nervous system (CNS). Some of these reflexes were characterized by segmental organization and others by nonsegmental organization. The spinal cord was essential for the segmental reflexes, while the supraspinal cord was essential for the nonsegmental generalized reflexes. The generalized reflex was elicited by stimulation to various spinal segments, particularly by stimulation to limbs.
To investigate the changes in surface and intramuscular electromyographic (EMG) activity at latent trigger points (TrPs) in the extensor carpi radialis brevis muscle after injection of either glutamate or isotonic saline into latent TrPs in the infraspinatus muscle.
Nociceptive muscle stimulation was obtained by a bolus injection of glutamate (0.2 mL, 0.5 M) into a latent TrP located in the right infraspinatus muscle in 12 healthy volunteers. A bolus of isotonic saline (0.9%, 0.2 mL) injection served as control. Injections were guided by intramuscular EMG showing resting spontaneous electrical activity at the latent myofascial TrP in the infraspinatus muscle. Intramuscular (at the TrP) and surface EMG activities of both infraspinatus and extensor carpi radialis brevis muscles were recorded before, during, and after injection for a period of 6 minutes to monitor changes produced in EMG activity.
Glutamate injection into latent TrPs induced higher pain intensity than isotonic saline injection (P<0.001). The analysis of variance showed a significant increase in root mean square score of intramuscular EMG activity at TrP in the extensor carpi radialis brevis after glutamate (mean+/-SD: 212.0+/-215.6 microV) but not isotonic saline (mean+/-SD: 74.2+/-72.2 microV) injections (P<0.001). No changes in surface EMG activity were found. No significant changes in root mean square of intramuscular and surface EMG activity in the infraspinatus muscle were found.
Our results show that an increased nociceptive activity at latent TrPs in the infraspinatus muscle may increase motor activity and sensitivity of a TrP in distant muscles at a same segmental level.
To investigate the remote effect of acupuncture on the pain intensity and the endplate noise (EPN) recorded from a myofascial trigger point (MTrP) of the upper trapezius muscle.
Randomized controlled trial.
University hospital.
Patients (N=20) with active MTrPs in upper trapezius muscles and no experience in acupuncture therapy.
Patients were divided into 2 groups. Those in the control group received sham acupuncture, and those in the acupuncture group received modified acupuncture therapy with needle insertion into multiple loci to elicit local twitch responses. The acupuncture points of Wai-guan and Qu-chi were treated.
Subjective pain intensity (numerical pain rating scale) and mean EPN amplitude in the MTrP of the upper trapezius muscle.
The pain intensity in the MTrP was significantly reduced after remote acupuncture (from 7.4+/-0.8 to 3.3+/-1.1; P<.001), but not after sham acupuncture (from 7.4+/-0.8 to 7.1+/-0.9; P>.05). The mean EPN amplitude was significantly lower than the pretreatment level after acupuncture treatment (from 21.3+/-9.5 microV to 9.5+/-3.5 microV; P<.01), but not after sham acupuncture treatment (from 19.6+/-7.6 microV to 19.3+/-7.8 microV; P>.05). The change in the pain intensity was significantly correlated with the change of EPN amplitude (r=0.685).
Both subjective changes in the pain intensity and objective changes of the EPN amplitude in the MTrP region of the upper trapezius muscle were found during and after acupuncture treatment at the remote ipsilateral acupuncture points. This study may further clarify the physiological basis of the remote effectiveness of acupuncture therapy for pain control.
To investigate the remote effect of dry needling on the irritability of a myofascial trigger point in the upper trapezius muscle.
Thirty-five patients with active myofascial trigger points in upper trapezius muscles were randomly divided into two groups: 18 patients in the control group received sham needling, and 17 patients in the dry-needling group received dry needling into the myofascial trigger point in the extensor carpi radialis longus muscle. The subjective pain intensity, pressure pain threshold, and range of motion of the neck were assessed before and immediately after the treatment.
Immediately after dry needling in the experimental group, the mean pain intensity was significantly reduced, but the mean pressure threshold and the mean range of motion of cervical spine were significantly increased. There were significantly larger changes in all three parameters of measurement in the dry-needling group than that in the control group.
This study demonstrated the remote effectiveness of dry needling. Dry needling of a distal myofascial trigger point can provide a remote effect to reduce the irritability of a proximal myofascial trigger point.
The gate control theory of pain describes the modulation of sensory nerve impulses by inhibitory mechanisms in the central nervous system. One of the oldest methods of pain relief is hyperstimulation analgesia produced by stimulating myofascial trigger points by dry needling, acupuncture, intense cold, intense heat, or chemical irritation of the skin. The moderate-to-intense sensory input of hyperstimulation analgesia is applied to sites over, or sometimes distant from, the pain. A brief painful stimulus may relieve chronic pain for long periods, sometimes permanently. Pain may be relieved by "closing the gate" by means of a central biasing mechanism possibly located in the brainstem reticular formation. Prolonged relief may require the disruption of reverberatory neural circuits responsible for the "memory" of pain. The termination of pain by either hyperstimulation, or by local injection of an anesthetic, normalizes function, which helps to prevent recurrence of abnormal neural activity. Thus, modulation of sensory inputs by use of many techniques may reduce pain more than by surgically interrupting the sensory input.
This study was designed to investigate the effects of injection with a local anesthetic agent or dry needling into a myofascial trigger point (TrP) of the upper trapezius muscle in 58 patients. Trigger point injections with 0.5% lidocaine were given to 26 patients (Group I), and dry needling was performed on TrPs in 15 patients (Group II). Local twitch responses (LTRs) were elicited during multiple needle insertions in both Groups I and II. In another 17 patients, no LTR was elicited during TrP injection with lidocaine (9 patients, group Ia) or dry needling (8 patients, group IIa). Improvement was assessed by measuring the subjective pain intensity, the pain threshold of the TrP and the range of motion of the cervical spine. Significant improvement occurred immediately after injection into the patients in both group I and group II. In Groups Ia and Ib, there was little change in pain, tenderness or tightness after injection. Within 2-8 h after injection or dry needling, soreness (different from patients' original myofascial pain) developed in 42% of the patients in group I and in 100% of the patients in group II. Patients treated with dry needling had postinjection soreness of significantly greater intensity and longer duration than those treated with lidocaine injection. The author concludes that it is essential to elicit LTRs during injection to obtain an immediately desirable effect. TrP injection with 0.5% lidocaine is recommended, because it reduces the intensity and duration of postinjection soreness compared with that produced by dry needling.
To review recent clinical and basic science studies on myofascial trigger points (MTrPs) to facilitate a better understanding of the mechanism of an MTrP.
English literature in the last 15 years regarding scientific investigations on MTrPs in either humans or animals.
Research works, especially electrophysiologic studies, related to the pathophysiology of MTrP.
(1) Studies on an animal model have found that a myofascial trigger spot (MTrS) in a taut band of rabbit skeletal muscle fibers is similar to a human MTrP in many aspects. (2) An MTrP or an MTrS contains multiple minute loci that are closely related to nerve fibers and motor endplates. (3) Both referred pain and local twitch response (characteristics of MTrPs) are related to the spinal cord mechanism. (4) The taut band of skeletal muscle fibers (which contains an MTrP or an MTrS in the endplate zone) is probably related to excessive release of acetylcholine in abnormal endplates.
The pathogenesis of an MTrP appears to be related to integrative mechanisms in the spinal cord in response to sensitized nerve fibers associated with abnormal endplates.
This study examines the counterirritation phenomenon of experimental pain in human subjects. Phasic pain induced by intracutaneous electrical stimuli was simultaneously applied with tonic pain induced by ischemic muscle work. Pain ratings, spontaneous EEG and evoked potentials were measured. We found a significant reduction of phasic pain ratings during and 10 min after tonic pain. The late somatosensory evoked potentials as neurophysiological correlates of phasic pain sensation were attenuated until 20 min after tonic pain offset. The extent of phasic pain relief due to concomitant tonic pain was small but significant, comparable to the effect of a regular systemic dose of a narco-analgesic drug in this experimental pain model. On the other hand, no modulations in the late components of the auditory evoked potential and the power spectrum of the spontaneous EEG were observed. These variables reflect the attention and vigilance of the subject and are well-known to be affected by opioids. The only exception was an increase of beta power, which might reflect hyperarousal during tonic pain. These results support the suggestion, that the analgesic effect of heterotopic noxious stimulation in humans is based on the activation of a specific inhibitory pain control system. Systemic release of endogenous opioids is unlikely to be involved, because the typical effects of opioids on the EEG were not observed.
Numerous studies have demonstrated that acupuncture and moxibustion induce analgesic effects. This study examined whether diffuse noxious inhibitory controls (DNIC) participated in acupuncture and moxibustion induced-analgesia. Single unit extracellular recordings from neurons in the trigeminal nucleus caudalis of urethane-anesthetized Wistar rats were obtained with a glass micropipette. A total of 52 single units, including 36 wide dynamic range (WDR), 5 nociceptive specific (NS) and 11 low-threshold mechanoreceptive (LTM) units were examined. During noxious test stimulation (cutaneous pinch or electrical stimulation), acupuncture, moxibustion or pinch stimulation was applied as the conditioning stimulus to the remote area of the receptive fields. When the conditioning stimulation induced rapid suppression of noxious receptive field stimulation response, examination revealed that various areas of the entire body were affected and suppression increased in an intensity-dependent manner. These features resemble DNIC phenomena. The suppression was observed on both WDR and NS neurons but not on LTM neurons. Eight of 16 WDR neurons examined were inhibited by acupuncture, five of 14 by moxibustion, and seventeen of 21 by pinching stimulation. Of the NS neurons, one of 2 units examined was suppressed by acupuncture, one of 2 by moxibustion, and two of 3 by pinch stimulation. Pinch stimulation induced the most profound suppression followed by manual acupuncture. Moxibustion induced moderate suppression with a long induction time. These results suggest that DNIC may be involved in the analgesic mechanism of acupuncture and moxibustion.
Dry needling of myofascial trigger points can relieve myofascial pain if local twitch responses are elicited during needling. Spontaneous electrical activity (SEA) recorded from an active locus in a myofascial trigger point region has been used to assess the myofascial trigger point sensitivity. This study was to investigate the effect of dry needling on SEA.
Nine adult New Zealand rabbits were studied. Dry needling with rapid insertion into multiple sites within the myofascial trigger spot region was performed to the biceps femoris muscle to elicit sufficient local twitch responses. Very slow needle insertion with minimal local twitch response elicitation was conducted to the other biceps femoris muscle for the control study. SEA was recorded from 15 different active loci of the myofascial trigger spot before and immediately after treatment for both sides. The raw data of 1-sec SEA were rectified and integrated to calculate the average integrated value of SEA.
Seven of nine rabbits demonstrated significantly lower normalized average integrated value of SEA in the treatment side compared with the control side (P < 0.05). The results of two-way analysis of variance show that the mean of the normalized average integrated value of SEA in the treatment group (0.565 +/- 0.113) is significantly (P < 0.05) lower than that of the control (0.983 +/- 0.121).
Dry needling of the myofascial trigger spot is effective in diminishing SEA if local twitch responses are elicited. The local twitch response elicitation, other than trauma effects of needling, seems to be the primary inhibitory factor on SEA during dry needling.
To compare the prevalence of motor endplate potentials (noise and spikes) in active central myofascial trigger points, endplate zones, and taut bands of skeletal muscle to assess the specificity of endplate potentials to myofascial trigger points.
This nonrandomized, unblinded needle examination of myofascial trigger points compares the prevalence of three forms of endplate potentials at one test site and two control sites in 11 muscles of 10 subjects. The endplate zone was independently determined electrically. Active central myofascial trigger points were identified by spot tenderness in a palpable taut band of muscle, a local twitch response to snapping palpation, and the subject's recognition of pain elicited by pressure on the tender spot.
Endplate noise without spikes occurred in all 11 muscles at trigger-point sites, in four muscles at endplate zone sites outside of trigger points (P = 0.024), and did not occur in taut band sites outside of an endplate zone (P = 0.000034).
Endplate noise was significantly more prevalent in myofascial trigger points than in sites that were outside of a trigger point but still within the endplate zone. Endplate noise seems to be characteristic of, but is not restricted to, the region of a myofascial trigger point.
To assess the effect of botulinum toxin type A (BTX-A) on the endplate noise prevalence in rabbit myofascial trigger spots to confirm the role of excessive acetylcholine release on the pathogenesis of myofascial trigger points and to develop an objective indicator of the effectiveness of BTX-A in the treatment of myofascial trigger points.
Eighteen adult New Zealand rabbits were divided into three groups that received a single bolus of BTX-A over a myofascial trigger spot region on one side of the biceps femoris muscle. Another 10 rabbits received multiple-point injections in a myofascial trigger spot where endplate noises were found. A control study was performed on the other side of the biceps femoris muscle. The endplate noise prevalence in a myofascial trigger spot region was assessed.
It was found that injection of BTX-A reduced the prevalence of endplate noise. No significant differences between a single bolus injection and multiple-point injections were noted, although there was some evidence that multiple-point injections might maintain the endplate noise decreasing effect much longer than a single injection.
This study demonstrated the suppressive effect of BTX-A on endplate noise prevalence in a myofascial trigger spot region. The prevalence of endplate noise in the myofascial trigger point region may be a useful objective indicator for evaluating the therapeutic effectiveness of BTX-A injection to treat myofascial trigger points.
From the author's direct involvement in clinical research, the conclusion has been drawn that clinically relevant long-term pain relieving effects of acupuncture (>6 months) can be seen in a proportion of patients with nociceptive pain. The mechanisms behind such effects are considered in this paper. From the existing experimental data some important conclusions can be drawn: Much of the animal research only represents short-term hypoalgesia probably induced by the mechanisms behind stress-induced analgesia (SIA) and the activation of diffuse noxious inhibitory control (DNIC). Almost all experimental acupuncture research has been performed with electro-acupuncture (EA) even though therapeutic acupuncture is mostly gentle manual acupuncture (MA). Most of the experimental human acupuncture pain threshold (PT) research shows only fast and very short-term hypoalgesia, and, importantly, PT elevation in humans does not predict the clinical outcome. The effects of acupuncture may be divided into two main components – acupuncture analgesia and therapeutic acupuncture.
A hypothesis on the mechanisms of therapeutic acupuncture will include: Peripheral events that might improve tissue healing and give rise to local pain relief through axon reflexes, the release of neuropeptides with trophic effects, dichotomising nerve fibres and local endorphins. Spinal mechanisms, for example, gate-control, long-term depression, propriospinal inhibition and the balance between long-term depression and long-term potentiation. Supraspinal mechanisms through the descending pain inhibitory system, DNIC, the sympathetic nervous system and the HPA-axis. Is oxytocin also involved in the long-term effects? Cortical, psychological, “placebo” mechanisms from counselling, reassurance and anxiety reduction.
This article explores how myofascial trigger points (MTrPs) may relate to musculoskeletal dysfunction (MSD) in the workplace and what might be done about it. The cause of much MSD and pain is often enigmatic to modern medicine and very costly, just as the cause of MTrPs has been elusive for the past century, despite an extensive literature that is confusing because of restricted regional approaches and a seemingly endless variety of names. MTrPs are activated by acute or persistent muscle overload, which is characteristic of MSD in the workplace. MTrPs can involve any, and sometimes many, of the skeletal muscles in the body and are a major, complex cause of musculoskeletal pain. The clinical and etiological characteristics of MTrPs have been underexplored by investigators, leading to undertraining of health care professionals, underappreciation of their clinical importance. MTrPs have no gold standard diagnostic criterion, and no routinely available laboratory or imaging test. MTrPs require a specific non-routine examination and muscle-specific treatment for prompt relief when acute, and also resolution of perpetuating factors when chronic. After identifying a critical false assumption, electrodiagnostic studies are now making encouraging progress toward clarifying the etiology of MTrPs based on the 5- or 6-step positive-feedback model of the integrated hypothesis. Specific research needs are noted. MTrPs are treatable and they deserve increased attention and consideration by research investigators and clinicians.
Myofascial pain syndrome (MPS) is caused by myofascial trigger points (MTrPs) located within taut bands of skeletal muscle fibers. Treating the underlying etiologic lesion responsible for MTrP activation is the most important strategy in MPS therapy. If the underlying pathology is not given the appropriate treatment, the MTrP cannot be completely and permanently inactivated. Treatment of active MTrPs may be necessary in situations in which active MTrPs persist even after the underlying etiologic lesion has been treated appropriately. When treating the active MTrPs or their underlying pathology, conservative treatment should be given before aggressive therapy. Effective MTrP therapies include manual therapies, physical therapy modalities, dry needling, or MTrP injection. It is also important to eliminate any perpetuating factors and provide adequate education and home programs to patients so that recurrent or chronic pain can be avoided.
This study was designed to investigate the correlation between the irritability of the myofascial trigger point (MTrP) and the prevalence of endplate noise (EPN) in the MTrP region of human skeletal muscle.
Twenty normal subjects with latent MTrPs and 12 patients with active MTrPs in the upper trapezius muscles were recruited for this study. The patients reported the subjective pain intensity of the active MTrP (0-10). The MTrP and an adjacent non-MTrP site were confirmed and marked for the measurement of pressure pain threshold (with a pressure algometer) and the prevalence of EPN (with electromyographic recordings).
The prevalence of EPN in the MTrP regions was significantly higher (P < 0.01) in the active MTrPs than in the latent ones. However, no EPN could be found in the non-MTrP region near either the active or the latent MTrPs. The pain intensity and the pressure pain threshold were highly correlated with the prevalence of EPN in the MTrP region (r = 0.742 and -0.716, respectively).
The irritability of an MTrP is highly correlated with the prevalence of EPN in the MTrP region of the upper trapezius muscle. The assessment of EPN prevalence in an MTrP region may be applied to evaluate the irritability of that MTrP.
To investigate the changes in pressure pain threshold of the secondary (satellite) myofascial trigger points (MTrPs) after dry needling of a primary (key) active MTrP.
Single blinded within-subject design, with the same subjects serving as their own controls (randomized). Fourteen patients with bilateral shoulder pain and active MTrPs in bilateral infraspinatus muscles were involved. An MTrP in the infraspinatus muscle on a randomly selected side was dry needled, and the MTrP on the contralateral side was not (control). Shoulder pain intensity, range of motion (ROM) of shoulder internal rotation, and pressure pain threshold of the MTrPs in the infraspinatus, anterior deltoid, and extensor carpi radialis longus muscles were measured in both sides before and immediately after dry needling.
Both active and passive ROM of shoulder internal rotation, and the pressure pain threshold of MTrPs on the treated side, were significantly increased (P < 0.01), and the pain intensity of the treated shoulder was significantly reduced (P < 0.001) after dry needling. However, there were no significant changes in all parameters in the control (untreated) side. Percent changes in the data after needling were also analyzed. For every parameter, the percent change was significantly higher in the treated side than in the control side.
This study provides evidence that dry needle-evoked inactivation of a primary (key) MTrP inhibits the activity in satellite MTrPs situated in its zone of pain referral. This supports the concept that activity in a primary MTrP leads to the development of activity in satellite MTrPs and the suggested spinal cord mechanism responsible for this phenomenon.
Acupuncture has been accepted to effectively treat chronic pain by inserting needles into the specific "acupuncture points" (acupoints) on the patient's body. During the last decades, our understanding of how the brain processes acupuncture analgesia has undergone considerable development. Acupuncture analgesia is manifested only when the intricate feeling (soreness, numbness, heaviness and distension) of acupuncture in patients occurs following acupuncture manipulation. Manual acupuncture (MA) is the insertion of an acupuncture needle into acupoint followed by the twisting of the needle up and down by hand. In MA, all types of afferent fibers (Abeta, Adelta and C) are activated. In electrical acupuncture (EA), a stimulating current via the inserted needle is delivered to acupoints. Electrical current intense enough to excite Abeta- and part of Adelta-fibers can induce an analgesic effect. Acupuncture signals ascend mainly through the spinal ventrolateral funiculus to the brain. Many brain nuclei composing a complicated network are involved in processing acupuncture analgesia, including the nucleus raphe magnus (NRM), periaqueductal grey (PAG), locus coeruleus, arcuate nucleus (Arc), preoptic area, nucleus submedius, habenular nucleus, accumbens nucleus, caudate nucleus, septal area, amygdale, etc. Acupuncture analgesia is essentially a manifestation of integrative processes at different levels in the CNS between afferent impulses from pain regions and impulses from acupoints. In the last decade, profound studies on neural mechanisms underlying acupuncture analgesia predominately focus on cellular and molecular substrate and functional brain imaging and have developed rapidly. Diverse signal molecules contribute to mediating acupuncture analgesia, such as opioid peptides (mu-, delta- and kappa-receptors), glutamate (NMDA and AMPA/KA receptors), 5-hydroxytryptamine, and cholecystokinin octapeptide. Among these, the opioid peptides and their receptors in Arc-PAG-NRM-spinal dorsal horn pathway play a pivotal role in mediating acupuncture analgesia. The release of opioid peptides evoked by electroacupuncture is frequency-dependent. EA at 2 and 100Hz produces release of enkephalin and dynorphin in the spinal cord, respectively. CCK-8 antagonizes acupuncture analgesia. The individual differences of acupuncture analgesia are associated with inherited genetic factors and the density of CCK receptors. The brain regions associated with acupuncture analgesia identified in animal experiments were confirmed and further explored in the human brain by means of functional imaging. EA analgesia is likely associated with its counter-regulation to spinal glial activation. PTX-sesntive Gi/o protein- and MAP kinase-mediated signal pathways as well as the downstream events NF-kappaB, c-fos and c-jun play important roles in EA analgesia.
To better understand the mechanisms of therapeutic lasers for treating human myofascial trigger points, we designed a blinded controlled study of the effects of a therapeutic laser on the prevalence of endplate noise (EPN) recorded from the myofascial trigger spot (MTrS) of rabbit skeletal muscle.
In eight rabbits, one MTrS in each biceps femoris muscle was irradiated with a 660-nm, continuous-wave, gallium-aluminum-arsenate (GaAlAs) laser, at 9 J/cm2. The contralateral side of muscle was treated with a sham laser. Each rabbit received six treatments. The immediate and cumulative effects were assessed by the prevalence of EPN with electromyographic (EMG) recordings after the first and last treatments.
Compared with pretreatment values, the percentages of EPN prevalence in the experimental side after the first and last treatments were significantly reduced (P < 0.01 for both). The change in EPN prevalence in the experimental side was significantly greater than in the control side immediately after the first and last treatments (P < 0.05). However, no significant differences were noted between the first and last treatments (P > 0.05).
In our study, immediate and cumulative effects of a GaAlAs laser applied on MTrS were demonstrated on the basis of the assessment of EPN prevalence. It seems that laser irradiation may inhibit the irritability of an MTrS in rabbit skeletal muscle. This effect may be a possible mechanism for myofascial pain relief with laser therapy.
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