Myofascial Trigger Point Sensitivity Research Articles

Effectiveness of polarized polychromatic light therapy on myofascial trigger points in chronic non-specific low back pain: a single blinded randomized controlled trial

BackgroundPhototherapy has been used for the treatment of chronic low back pain. However, the effect of linear polarized polychromatic light (PL) has not been examined on myofascial trigger points in patients with chronic non-specific low back pain (NSLBP).ObjectivesTo investigate the effectiveness of PL on pain intensity, pain sensitivity of active myofascial trigger points (MTrPs) in gluteus medius (GM) and quadratus lamborum (QL) muscles, back disability, and lumbar range of motion in chronic NSLBP.MethodsForty-two participants of both genders with chronic NSLBP were randomly allocated into two equal groups: group A (Linear polarized polychromatic light (PL): 21 participants received polarized light therapy in the range of red and near-infrared rays on myofascial trigger points of bilateral GM and QL muscles for 5 min/point followed by stretching and strengthening exercises for 4 weeks. Group B (Sham PL): 21 participants received the same program but with sham linear polarized polychromatic light therapy. Numeric pain rating scale, pressure algometer, and Roland-Morris Disability Questionnaire were used to measure pain intensity, pain sensitivity (as represented by pain pressure threshold (PPT) of MTrPs of the target muscles and back disability respectively. Further, lumbar flexion, extension, and bilateral rotation were examined with a tape measure, while bilateral side bending were examined with a universal goniometer.ResultsAfter the intervention program, significant improvements (p < 0.05) in pain intensity, PPT of MTrPs of left GM (Effect Size (ES): 1.23) and bilateral QL muscles (ES Rt QL: 0.9; Lt QL: 1.56) were found in group A in comparison with group B. Nevertheless, the two groups displayed similar improvements (p > 0.05) in lumbar range of motion and back disability.ConclusionLinear polarized polychromatic light therapy in the range of red and near-infrared rays improves pain intensity and pain sensitivity of myofascial trigger points in chronic NSLBP.Trial registrationPACTR, PACTR202111577053926. Registered 22 June 2019-Prospectively registered.

Prevalence and sensitivity of trigger points in lumbo-pelvic-hip muscles in patients with patellofemoral pain syndrome

ObjectivesChanges in the activity of the lumbo-pelvic-hip muscles have been established as a major cause of patellofemoral pain syndrome (PFPS), a common orthopedic problem. The present study aimed to compare the prevalence and sensitivity of myofascial trigger points (MTrPs) in lumbo-pelvic-hip muscles in persons with and without PFPS. MethodsThirty women with PFPS and 30 healthy women 18–40 years old were recruited for this study. The prevalence of MTrPs was assessed by palpation, and pressure algometry was used to measure the pressure pain threshold. This study evaluated the areas where MTrPs are most commonly found in the lumbar muscles (internal oblique, erector spinae and quadratus lumborum), pelvic muscles (gluteus maximus, gluteus medius, gluteus minimus and piriformis), and hip muscles (hip adductor, quadriceps, hamstring, tensor fascia lata and sartorius). Independent t-tests were used to compare mean pressure pain thresholds between the two groups. Chi-squared tests were used to compare the prevalence of MTrPs. ResultsThe prevalence of MTrPs was significantly higher in most of the lumbo-pelvic-hip muscles in patients with PFPS compared to healthy persons. However, there were no significant differences between groups in the prevalence of MTrPs in the gluteus minimus or adductor muscles. The pressure pain threshold in lumbo-pelvic-hip muscles was lower in patients with PFPS compared to healthy participants. ConclusionIn patients with PFPS the prevalence of MTrPs in the lumbo-pelvic-hip region was higher, and the pressure pain threshold was lower, than in healthy people. Thus therapy to treat PFPS should target the lumbo-pelvic-hip muscles.

The Relationship between Rate of Algometer Application and Pain Pressure Threshold in the Assessment of Myofascial Trigger Point Sensitivity.

Pressure algometry is a commonly employed technique in the assessment of both regional and widespread musculoskeletal pain. Despite its acceptance amongst clinicians and scientists, the relationship between rate of pressure application (RoA) and pain pressure threshold (PPT) remains poorly understood. We set out to test the hypothesis that a strong, positive, linear relationship exists between the RoA and the PPT within the infraspinatus of young healthy subjects. Thirty-three participants were randomly recruited from the local university community. PPT measures were recorded from a clinically identified myofascial trigger point within the right infraspinatus muscle during pressure algometry. A total of 2 PPT measures were recorded using each of 3 different RoAs, including low (15 N/s), medium (35 N/s), and high (55 N/s). Three baseline trials were also conducted at 30 N/s. The Pearson's correlation coefficient between RoA and PPT was calculated for each subject and averaged across participants. The mean(SD) correlation between subjects was 0.77 (0.19), and the mean (SD) slope of the linear regression was 0.13 (0.09). Our results demonstrate that there is a strong, linear relationship between the RoA and PPT when using the pressure algometry technique. The low slope between RoA and PPT suggests clinicians can rely on PPT assessments despite small RoA fluctuations. Future research should explore this relationship further in a clinical population and in other muscles affected by chronic myofascial pain. Advancing cost-effective, reliable, and clinically feasible tools such as algometry is important to enhancing the diagnosis and management of chronic myofascial pain.

Effect of exams period on prevalence of Myofascial Trigger points and head posture in undergraduate students: Repeated measurements study

Myofascial Trigger points (MTrPs) may be caused or aggravated by many factors, such as mental stress associated with exams and impaired posture. To compare the prevalence and sensitivity of MTrPs, and forward head position (FHP) during exam period vs. mid-semester among physical therapy students. 39 physical therapy students were palpated for MTrPs in neck and shoulder muscles and were photographed laterally for FHP measurement during the academic semester and during the academic examination period. The subjects showed higher prevalence of active MTrPs in the right Trapezius and Levator Scapula muscles, and higher prevalence of latent MTrPs in the left Sternocleidomastoideus and Levator Scapula muscles during exams, as well as a higher rate of tenderness in suboccipital musculature. Physical therapy students show greater prevalence of MTrPs during exams. The authors recommend implementing preventative programs towards the examination period.

Dry Needling on the Infraspinatus Latent and Active Myofascial Trigger Points in Older Adults With Nonspecific Shoulder Pain: A Randomized Clinical Trial.

Background and Purpose:Shoulder pain is a prevalent condition in older adults. Some authors associate nonspecific shoulder pain with myofascial trigger points (MTrPs) in the infraspinatus muscle. Dry needling is recommended to relieve the MTrP pain of shoulders in the short term (<9 days). Active MTrPs dry needling improves shoulder pain and the irritability of the satellite MTrPs in the referred pain area. Nociceptive activity at a latent MTrP may influence motor activity and the sensitivity of MTrPs in distant muscles at a similar segmental level. Therefore, this study aimed to evaluate dry needling on 1 latent MTrP, in conjunction with 1 active MTrP, in the infraspinatus muscle of older adults with nonspecific shoulder pain.Methods:A single-center, randomized, single-blinded, controlled study (NCT02032602) was carried out. Sixty-six patients aged 65 years and older with trigger points in the ipsilateral infraspinatus of the painful shoulder were randomly assigned to (1) of (2) treatment groups. A session of dry needling on the infraspinatus was performed in (1) the most hyperalgesic active and latent MTrP or (2) only the most hyperalgesic active MTrP. The Numeric Rating Scale, the pressure pain threshold (primary outcome) on the anterior deltoid and extensor carpi radialis brevis latent MTrPs, and grip strength were assessed before, after, and 1 week after the intervention.Results:Statistically significant differences in the reduction of pain intensity (P ≤ .001; η2 = 0.159-0.269; d = 1.017-1.219) and the increase of pressure pain threshold (P < .001; η2 = 0.206-0.481; d = 0.870-1.924) were found for the (1) treatment group immediately and 1 week postintervention. Nevertheless, no statistical significant differences were found in grip strength (P >. 05; η2 = 0.006-0.033; d = 0.158-0.368).Conclusions:One dry needling intervention of the latent MTrP associated with the key active MTrP of the infraspinatus reduces pain intensity and the irritability of the satellite MTrPs located in the referred pain area in the short term in older adults with nonspecific shoulder pain.

The hypoalgesic effect of remote tactile sensory modulation on the mechanical sensitivity of trigger points: A randomized controlled study.

Sensitivity of the myofascial trigger point (MTrP) can be inhibited by electrical stimulation of remote site. However, it remains unclear whether remote pain control of the MTrP occurs in the same spinal segment or in the supraspinal system. The aims of this study were to identify whether the remote pain control occurs in the spinal segment corresponding to the MTrP or in the supraspinal system. Test subjects (n = 10) received transcutaneous electrical nerve stimulation for 5 minutes, whereas control subjects (n = 10) received no intervention. The threshold for tactile sensory modulation at the lateral elbow was assessed using Von Frey filaments. The pressure sensitivities of MTrPs in both the infraspinatus and upper trapezius muscles were quantified by algometry. Measurements were performed at baseline and 1 and 15 minutes after the intervention. Increases of the tactile threshold at the remote site decreased the sensitivity of the MTrP innervated by same spinal segment. However, no changes were observed at MTrP sites innervated by contralateral fibers or those from different spinal segment. MTrP sensitivity is more strongly affected by interventions at remote ipsilateral sites in the same spinal segment than by stimulation of extra-segmental sites.

Myofascial trigger points: spontaneous electrical activity and its consequences for pain induction and propagation

Active myofascial trigger points are one of the major peripheral pain generators for regional and generalized musculoskeletal pain conditions. Myofascial trigger points are also the targets for acupuncture and/or dry needling therapies. Recent evidence in the understanding of the pathophysiology of myofascial trigger points supports The Integrated Hypothesis for the trigger point formation; however unanswered questions remain. Current evidence shows that spontaneous electrical activity at myofascial trigger point originates from the extrafusal motor endplate. The spontaneous electrical activity represents focal muscle fiber contraction and/or muscle cramp potentials depending on trigger point sensitivity. Local pain and tenderness at myofascial trigger points are largely due to nociceptor sensitization with a lesser contribution from non-nociceptor sensitization. Nociceptor and non-nociceptor sensitization at myofascial trigger points may be part of the process of muscle ischemia associated with sustained focal muscle contraction and/or muscle cramps. Referred pain is dependent on the sensitivity of myofascial trigger points. Active myofascial trigger points may play an important role in the transition from localized pain to generalized pain conditions via the enhanced central sensitization, decreased descending inhibition and dysfunctional motor control strategy.

Effect of ischemic pressure using a Backnobber II device on discomfort associated with myofascial trigger points

The purpose of this study was to assess the effectiveness of ischemic pressure on myofascial trigger point (MTrP) sensitivity. Randomized, controlled study with the researcher assessing MTrP sensitivity blinded to the intervention. Twenty-eight people with two MTrPs in the upper back musculature. The sensitivity of two MTrPs in the upper back was assessed with a JTECH algometer. One of the two MTrPs was randomly selected for treatment with a Backnobber II, while the other served as a control. Pre- and post-test pressure-pain thresholds of the MTrPs There was a significant difference between the pre- and post-test sensitivities of the treated and non-treated MTrPs (p=0.04). The results of this study confirm that the protocol of six repetitions of 30-s ischemic compression with the Backnobber II rendered every other day for a week was effectiveinreducing MTrP irritability.

Changes in a patient with neck pain after application of ischemic compression as a trigger point therapy

To describe the immediate effects of ischemic compression (IC) as a trigger point therapy in a case of a patient with neck pain. The application of IC is a safe and effective method to successfully treat elicited myofascial trigger points. The purpose of this method is to deliberate the blockage of blood in a trigger point area in order to increase local blood flow. This washes away waste products, supplies necessary oxygen and helps the affected tissue to heal. In this case study, we treated a 27-year-old female patient with a medical report of neck pain for at least four months. The physical examination revealed a neck pain and stiffness at the left side and pain increases when moving the neck. An active myofascial trigger point was found in the left trapezius muscle. The following data were recorded: active range of motion of cervical rachis measured with a cervical range of motion instrument, basal electrical activity of the left trapezius measured with electromyography, and pressure tolerance of the myofascial trigger point measured with visual analogue scale, assessing local pain evoked by the application of 2.5 kg/cm2 pressure with an analogue algometer. Immediately after application of the IC, all measured parameters improved compared to base line. The application of IC has been shown effective in the treatment of myofascial trigger points in a patient with neck pain. The results show a relation between active range of motion of cervical rachis, basal electrical activity of the trapezius muscle and myofascial trigger point sensitivity. In this case of a patient with neck pain, active range of motion of cervical rachis, basal electrical activity of the trapezius muscle and myofascial trigger point sensitivity gaining short-term positive effects with the application of one single ischemic compression session. Nevertheless, randomized controlled double-blinded studies should be conducted in future to examine the effectiveness of this ischemic compression technique in case of the presence of myofascial trigger points in the neck.

Topographical mapping and mechanical pain sensitivity of myofascial trigger points in the infraspinatus muscle

Objectives To screen for the presence of latent and active myofascial trigger points (MTrPs) in patients with unilateral shoulder and arm pain and perform topographical mapping of mechanical pain sensitivity bilaterally in the infraspinatus muscles. Methods Nineteen patients with unilateral musculoskeletal shoulder pain participated in the study. The area overlying the infraspinatus on each side was divided into 10 adjacent sub-areas of 1 cm 2, corresponding to the area of a pressure algometer probe. Pressure pain threshold (PPT) was measured in each sub-area bilaterally in the infraspinatus muscles. Following PPT measurement, an acupuncture needle was inserted into each sub-area five times in different directions in order to induce local twitch response and/or referred pain. Results A significantly lower PPT level in the infraspinatus muscle was detected on the painful side compared with the non-painful side ( P = 0.001). PPT at midfiber region of the infraspinatus muscles was lower than that at other muscle parts ( P < 0.05). Multiple, but not single, active MTrPs were found in the infraspinatus muscle on the painful side and there were also multiple latent MTrPs bilaterally in the infraspinatus muscles. PPT at active MTrPs was much lower than the latent MTrPs and again lower than the non-MTrPs. Conclusions There exists bilateral mechanical hyperalgesia in patients with unilateral shoulder pain. Further, the association of multiple active MTrPs with unilateral shoulder pain and the heterogeneity of mechanical pain sensitivity distribution suggest a crucial role of peripheral sensitization in chronic myofascial pain conditions. Additionally, the locations of MTrPs identified with dry needling correspond well to PPT topographical mapping, suggesting that dry needling and PPT topographical mapping are sensitive techniques in the identification of MTrPs.

Randomized controlled study of the antinociceptive effect of ultrasound on trigger point sensitivity: novel applications in myofascial therapy?

Objective : To investigate whether therapeutic ultrasound modulates the pain sensitivity of myofascial trigger points. Design : Repeated measures, single-blinded randomized controlled trial of ultrasound treatment of trigger points. Setting : Outpatient injury rehabilitation clinic. Subjects : Forty-four patients (22 males, 22 females) with trigger points identified within the trapezius muscle. Interventions : Five-minute therapeutic intensity of ultrasound versus 5-min low-intensity application of ultrasound to a trapezius myofascial trigger point locus. Main measures : Pain pressure threshold readings were measured at the trapezius trigger point site before and after exposure to the ultrasound intervention. Results : Pain pressure threshold scores increased an average of 44.4 (14.2)% after therapeutic exposure to ultrasound (pre-ultrasound test 35.4 (8.5) N, post-ultrasound test 51.1 (12.8) N). No significant difference in pain pressure threshold scores was observed with low-intensity ultrasound exposures (pre-ultrasound 36.1 (6.1) N, post-ultrasound 36.6 (4.8) N). Conclusions : Therapeutic exposures to ultrasound reduce short-term trigger point sensitivity. Ultrasound may be a useful clinical tool for the treatment and management of trigger points and myofascial pain syndromes.

Inhibitory effect of dry needling on the spontaneous electrical activity recorded from myofascial trigger spots of rabbit skeletal muscle.

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.

Effects of transcutaneous electrical nerve stimulation on myofascial pain and trigger point sensitivity

The effects of transcutaneous electrical nerve stimulation (TENS) on myofascial pain and trigger point sensitivity were assessed. Four modes of TENS and a no-stimulation control were compared in a double-blind design. Stimulation, carried out for 10 min on 60 subjects (12/group), showed significant pain reductions with 100 Hz, 250 msec stimulation followed by 100 Hz, 50 msec and then pain suppressor TENS. No pain reductions were found in the 2 Hz, 250 msec TENS or the control. No significant alteration in myofascial trigger point sensitivity, assessed with the pressure algometer, was found between the groups. The results suggest that high frequency, high intensity TENS is effective in reducing myofascial pain, and that these pain reductions do not reflect changes in local trigger point sensitivity.

Quantification of changes in myofascial trigger point sensitivity with the pressure algometer following passive stretch

In order to determine the relationship between trigger point sensitivity and the referred symptoms of myofascial pain, VAS ratings of referred pain intensity and pressure algometer measures of myofascial trigger point sensitivity were taken pre and post treatment of the muscle containing the trigger point with passive stretch. The results in 20 subjects, experiencing unilateral or bilateral myofascial head and neck pain, showed that myofascial trigger point sensitivity decreases in response to passive stretch as assessed by the pressure algometer, and that trigger point sensitivity and intensity of referred pain are related.

Reliability of the pressure algometer as a measure of myofascial trigger point sensitivity

Three studies are presented demonstrating the reliability of the pressure algometer as an index of myofascial trigger point sensitivity. The first study showed high reliability between and within experimenters when measuring marked trigger point locations. In study 2, significant between experimenter reliability in locating and measuring the same unmarked trigger point locations was shown, while study 3 supported the idea that trigger points are discrete points of focal tenderness within the muscle. The ability to quantify and reliably measure trigger point sensitivity opens the door to a range of clinical and research possibilities for myofascial and related musculoskeletal pain problems.