Trigger Point Diagnosis: At Last, the First Word on Consensus

Latent myofascial trigger points injection therapy for adult cough variant asthma: A randomized controlled trial

Background

Cough variant asthma (CVA) is a chronic inflammatory airway disease characterized by airway hyper-responsiveness (AHR), of which cough is the only symptom. The cough is a result of the contraction of the vocal cords, diaphragm, sternocleidomastoid muscle, and other respiratory related muscles caused by the AHR. Long-term chronic coughing can lead to repetitive contraction and chronic strain of the muscles involved in the head and neck, ultimately contributing to the formation of latent myofascial trigger points (MTrPs). In turn, latent MTrPs can also irritate or compress the nerves around them, triggering cough. The date indicated that latent MTrPs can induce autonomic phenomena and are effective in allergic rhinitis. But their roles in asthma are unclear. In this article, the efficacy and safety of latent MTrPs injection therapy in CVA were investigated.

Methods

This randomized controlled trial was conducted with 110 patients. Patients were assigned to the intervention or control group in a 1:1.5 ratio. Intervention group (n = 44): single injection therapy with latent MTrPs. Control group (n = 66): budesonide-formoterol plus montelukast for 8 weeks. During the 36-week follow up period, the recurrence rate at week 36, cough visual analog scale (VAS), ACT (asthma control test)-scores, ACQ5 (asthma control questionnaire)-scores, AQLQ (asthma quality of life questionnaire)-scores, proportion of using rescue medication, and adverse events were evaluated.

Results

The recurrence rate at week 36 was lower in the intervention group than in the control group (36 weeks, 5.0 vs. 34.55%, p = 0.001). There were significant differences between groups in change from baseline to 36 weeks in VAS [36 weeks, 1.70 (1.49) vs. 3.18 (2.04), p < 0.001]; ACT-score [36 weeks, 21.38 (2.65) vs. 18.53 (3.00), p < 0.001]; ACQ5-score [36 weeks, 0.85 (0.55) vs. 1.52 (0.62), p < 0.001]; AQLQ-score [36w, 174.40 (18.22) vs. 151.69 (24.04), p < 0.001]; proportion of using rescue medication (36 weeks, 5.0 vs. 29.1%, p = 0.003). Fewer adverse events occurred in the two groups.

Conclusion

Latent myofascial trigger points injection therapy provided long-acting, practical, short treatment duration and safety methods for CVA.

Clinical Trials Registration

http://www.chictr.org.cn/index.aspx, Chinese Clinical Trial Registry Center, ChiCTR2100044079.

Dexmedetomidine inhibits abnormal muscle hypertrophy of myofascial trigger points via TNF-α/ NF-κB signaling pathway in rats

Myofascial pain syndrome (MPS) is a chronic pain disorder with inflammation-related primarily characterized by the presence of myofascial trigger points (MTrPs). Myocyte enhancer factor 2C (MEF2C) is involved in the occurrence of a variety of skeletal muscle diseases. However, it is not yet clear if MEF2C is involved in MTrPs. The purpose of this study was to investigate whether MEF2C was involved in the inflammatory pathogenesis of MTrPs. In the present study, we used RNA sequencing (RNA-seq) to compare the differential expression of myocyte enhancer factor 2C (MEF2C) in healthy participants and MTrPs participants. The widely used rat MTrPs model was established to research the upstream and downstream regulatory mechanism of MEF2C and found that MEF2C was significantly increased in patients with MTrPs. Dexmedetomidine (Dex) was injected intramuscularly in the MTrPs animal to assess its effects on MEF2C. The expression of MEF2C protein and mRNA in skeletal muscle of rats in the MTrPs group were up-regulated. In addition, the expression of TNF- α, p-P65, MLCK, and Myocilin (MyoC) was up-regulated and the mechanical pain threshold was decreased. Peripheral TNF- α injection significantly decreased the mechanical pain threshold and increased the expression of p-P65, MLCK, MEF2C, and MyoC in healthy rats. Maslinic acid increased the mechanical pain threshold and inhibited the expression of p-P65, MLCK, MEF2C, and MyoC. In addition, peripheral injection of DEX in MTrPs rats also inhibited the expression of TNF- α, p-P65, MLCK, MEF2C, and MyoC. These results suggest that MEF2C is involved in the inflammatory pathogenesis of MTrPs and DEX serves as a potential therapeutic strategy for the treatment of MPS.

Peripheral EphrinB1/EphB1 signalling attenuates muscle hyperalgesia in MPS patients and a rat model of taut band-associated persistent muscle pain

Background

Myofascial pain syndrome (MPS) is an important clinical condition that is characterized by chronic muscle pain and a myofascial trigger point (MTrP) located in a taut band (TB). Previous studies showed that EphrinB1 was involved in the regulation of pathological pain via EphB1 signalling, but whether EphrinB1-EphB1 plays a role in MTrP is not clear.

Methods

The present study analysed the levels of p-EphB1/p-EphB2/p-EphB3 in biopsies of MTrPs in the trapezius muscle of 11 MPS patients and seven healthy controls using a protein microarray kit. EphrinB1-Fc was injected intramuscularly to detect EphrinB1s/EphB1s signalling in peripheral sensitization. We applied a blunt strike to the left gastrocnemius muscles (GM) and eccentric exercise for 8 weeks with 4 weeks of recovery to analyse the function of EphrinB1/EphB1 in the muscle pain model.

Results

P-EphB1, p-EphB2, and p-EphB3 expression was highly increased in human muscles with MTrPs compared to healthy muscle. EphB1 (r = 0.723, n = 11, P < 0.05), EphB2 (r = 0.610, n = 11, P < 0.05), and EphB3 levels (r = 0.670, n = 11, P < 0.05) in the MPS group were significantly correlated with the numerical rating scale (NRS) in the MTrPs. Intramuscular injection of EphrinB1-Fc produces hyperalgesia, which can be partially prevented by pre-treatment with EphB1-Fc. The p-EphB1 contents in MTrPs of MPS animals were significantly higher than that among control animals (P < 0.01). Intramuscular administration of the EphB1 inhibitor EphB1-Fr significantly suppressed mechanical hyperalgesia.

Conclusions

The present study showed that the increased expression of p-EphB1/p-EphB2/p-EphB3 was related to MTrPs in patients with MPS. This report is the first study to examine the function of EphrinB1-EphB1 signalling in primary muscle afferent neurons in MPS patients and a rat animal model. This pathway may be one of the most important and promising targets for MPS.

Short-term effects of dry needling at a spinal and peripheral site on functional outcome measures, strength, and proprioception among individuals with a lateral ankle sprain

BACKGROUND

The purpose of the study was to compare the effects of spinal and peripheral dry needling with peripheral dry needling alone, in addition to a strength and proprioception home exercise program, on pain, balance, strength, proprioception, and functional limitations among individuals with a history of a lateral ankle sprain.

METHODS

The study design is a single-blinded, repeated measures randomized clinical trial. Thirty-four participants, aged 18-50, with a history of a lateral ankle sprain within the last twelve months were randomly assigned into a peripheral dry needling (PDN) group or a spinal and peripheral dry needling (SPDN) group. Outcome measures included a pain assessment, strength testing, Modified Clinical Test of Sensory Integration and Balance, physical performance on hop tests, Cumberland Ankle Instability Tool and the Foot and Ankle Disability Index assessed at baseline, one week, and at four to six weeks.

RESULTS

The mixed model ANOVAs showed significant side by time interaction (p < 0.05) for inverter/dorsiflexion strength and significant improvements in side, time, and side by time (p < 0.05) for the CAIT.

CONCLUSION

Trigger point dry needling demonstrated short-term improvements in strength of the inverters/dorsiflexors and the CAIT scores on the involved side at one week and at four to six weeks irrespective of a PDN or SPDN approach.

DISCUSSION

These results suggest that improvements in strength and function can be achieved with PDN without additional needling at the corresponding spinal level.

The pathophysiological nature of sarcomeres in trigger points in patients with myofascial pain syndrome: A preliminary study

BACKGROUND

Myofascial pain syndrome (MPS) has a high global prevalence and is associated with myofascial trigger points (MTrPs) in taut bands or nodules. Little is known about the aetiology. The current study assessed the pathophysiological characteristics of MTrPs in MPS patients.

METHODS

Biopsies of the trapezius muscle were collected from the MTrPs of MPS patients (MTrP group; n = 29) and from healthy controls (control group; n = 24), and their morphologies were analysed via haematoxylin-eosin (H&E) and Masson staining. A protein microarray was used to detect the receptor tyrosine kinase (RTK) family proteins. mRNA and long non-coding RNA (lncRNA) sequencing and analysis were conducted, and immunohistochemistry and Western blotting were used to examine the expression of EphB and Rho family proteins.

RESULTS

Abnormally contracted sarcomeres showed enlarged, round fibres without inflammation or fibrosis. An lncRNA-mRNA network analysis revealed activation of muscle contraction signalling pathways in MTrP regions. Among RTK family proteins, 15 exhibited increased phosphorylation, and two exhibited decreased phosphorylation in the MTrP regions relative to control levels. In particular, EphB1/EphB2 phosphorylation was increased on the muscle cell membranes of abnormal sarcomeres. RhoA and Rac1, but not cell division control protein 42 (Cdc42), were activated in the abnormal sarcomeres.

CONCLUSIONS

EphB1/EphB2 and RhoA/Rac1 might play roles in the aetiology of abnormally contracted sarcomeres in MTrPs without inflammatory cell infiltration and fibrotic adhesion.

SIGNIFICANCE

Contracted sarcomeres were found in MTrP regions, which is consistent with the MTrP formation hypothesis. EphB1/EphB2 and RhoA/Rac1 might play roles in the sarcomere contractile sites of MTrPs, which may be promising therapeutic targets.

Peripheral FGFR1 Regulates Myofascial Pain in Rats via the PI3K/AKT Pathway

Myofascial pain syndrome (MPS) is a type of skeletal pain identified by myofascial trigger points (MTrPs). The formation of MTrPs is linked to muscle damage. The fibroblast growth factor receptor (FGFR1) has been found to cause pain sensitivity while repairing tissue damage. The aim of the current study was to explore the mechanism of FGFR1 in MTrPs. We used a RayBio human phosphorylation array kit to measure p-FGFR1 levels in human control subjects and patients with MTrPs. P-FGFR1 was upregulated in the patients with MTrPs. Then a rat model of MPS was established by a blunt strike on the left gastrocnemius muscles (GM) and eccentric-exercise for 8 weeks with 4 weeks of recovery. After establishing the MPS model, the morphology of the GM changed, and the differently augmented sizes of round fibers (contracture knots) in the transverse section and fusiform shapes in the longitudinal section were clearly seen in the rats with myofascial pain. The expression of p-FGFR1 was upregulated on the peripheral nerves and dorsal root ganglion neurons in the MTrPs group. The spinal Fos protein expression was increased in the MTrPs group. Additionally, the mechanical pain threshold was reduced, and the expression of FGF2, p-FGFR1, PI3K-p110γ, and p-AKT increased in the MTrPs group. PD173074 increased the mechanical pain threshold of the MTrPs group, and inhibited the expression of p-FGFR1, PI3K-p110γ, and p-AKT. Moreover, LY294002 increased the mechanical pain threshold of the MTrPs group. These findings suggest that FGFR1 may regulate myofascial pain in rats through the PI3K/AKT pathway.

Why are assumptions passed off as established knowledge?

In this paper we attempt to explain the problems that can arise when assumptions made by experts in their respective fields of Medicine become widely accepted as established knowledge. Our hypothesis is that these problems are in large part attributable to a failure of the experts to follow the principles of logical argument. Empirical data to evaluate our hypothesis derives from an analysis of the reasoning processes employed in the generation of three syndromes drawn from the clinical discipline of Pain Medicine: myofascial pain, shoulder impingement and central sensitisation. We demonstrate a failure by the proponents of these syndromes to structure their scientific arguments in a logically valid fashion, which lead them to promote assumptions to the status of facts. In each instance those in relevant scientific journals responsible for content review accepted - and thereby promulgated - this fundamental error in reasoning. The wide acceptance of each of these assumptions as established knowledge affirms our hypothesis. Furthermore, we show that such uncritical acceptance has had significant consequences for many patients.