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PubMedDate not supplied

Myofascial pain in patients with postthoracotomy pain syndrome.

OBJECTIVE: Postthoracotomy pain syndrome is generally considered to be neuropathic pain due to intercostal nerve injury. However, nonneuropathic pain can also occur following thoracic surgery. We present a series of cases with postthoracotomy pain syndrome in which myofascial pain was thought to be a causative component of postthoracotomy pain syndrome. CASE REPORT: Twenty-seven patients (17 men and 10 women) were treated with trigger point injections, intercostal nerve blocks, and/or epidural blocks. Clinical criteria were used to diagnose the myofascial pain. A visual analogue scale was used, and sensory disturbances were recorded before and after treatment. A trigger point in a taut muscular band within the scapular region, which we diagnosed as myofascial pain, was observed in 67% of the patients. The existence of this trigger point significantly increased the rate of success for the treatments. CONCLUSIONS: Postthoracotomy pain may result, at least in part, from a nonneuropathic origin (myofascial pain). It is recommended that each patient be examined in detail to determine whether there is a trigger point in a taut muscular band within the scapular region. If found, this point is suggested as a good area for anesthetic injection.

Aged↗
PubMed1996

Pressure algometry in manual therapy.

SUMMARY. The pressure pain threshold (PPT), i.e. the least stimulus intensity at which a subject perceives pain, was studied in 30 patients with chronic unilateral pain in the shoulder and arm region.Fourteen trigger points were investigated on both sides of the body using pressure algometry. Eight paravertebral points and six points in the shoulder and arm region were evaluated. Each location was examined twice. The patients were tested by one examiner.The intraobserver reliability of PPT measurements was considered to be good. The Intraclass Correlation Coefficients of reliability (ICC), based on two repeated PPT measurements varied between 0.64 and 0.96. The painful side of the body was found to be more sensitive than the non-painful side, although there was not always a significant difference at the 0.05 level. The PPT was found to be higher in males than in females (P < 0.05). Females demonstrated lower PPTs than males at each trigger point. It was established that pressure tenderness varies over individual trigger points. Significant regional differences in PPT values were observed (P < 0.05). PPT values decreased in a cranial direction in the spine and in a caudal direction in the upper limb.Although the authors expected to find segmentally reduced PPT values on the painful side of the body, a generalized reduction of PPT values was present at all peripheral and spinal segmental sites. Some correlations between segmentally related trigger points were found by factor analysis. Copyright 1996 Harcourt Publishers Ltd.

Journal Article↗
PubMedDate not supplied

The assessment of intramuscular discrimination using signal detection theory: its potential contribution to chiropractic.

INTRODUCTION: Most studies on sensory changes after manual therapies have focused on pain sensitivity. This ignores the wider range of sensory alternations that may be important in assessing patient functioning and neglects the issue of bias, which is inherent in most methods of pain assessment employing threshold methodology. Signal detection theory (SDT) addresses the issue of bias and provides a measurement of intramuscular discrimination--the ability to discriminate between two stimuli--which can be assessed over the full range of sensation. This paper will discuss the strengths and limitations of SDT and report on the effects of trigger point therapy and manipulation on intramuscular discrimination to illustrate the potential contribution of this methodology to chiropractic. METHODS: Intramuscular needle electrodes were used to provide a pair of electrical stimuli to the forearm extensor muscles. Subjects were asked to assess the differences between stimuli before and after treatment. The treatments consisted of manual trigger point therapy applied to the forearm extensors, cervical spine manipulation and a control treatment. RESULTS: After the trigger point therapy, there was a significant improvement in the ability of the subjects to discriminate between intramuscular signals to treated muscle. Some individual subjects showed alterations in ability to discriminate after cervical spine manipulation but the effect was not significant in the group as a whole. CONCLUSIONS: The methodology of signal detection theory provides a promising, bias-free method of assessing changes in intramuscular sensation after various treatments. In these experiments, trigger point therapy was found to enhance intramuscular discrimination, suggesting that a peripheral reflex may be involved.

Adolescent↗
PubMed1985

Myofascial pain syndrome: electromyographic changes associated with local twitch response.

Electromyographic (EMG) recordings of the local twitch response in sixteen subjects with pain from active myofascial trigger points in the upper trapezius muscle were examined and compared with recordings from the contralateral normal muscle bands in the same individual. Needle electromyography and a specific reproducible snapping palpation technique were used to elicit and record the local twitch response. The mean value for the EMG recordings of bands with trigger points versus the normal muscle bands using the visual scoring method were 3.81 and .81 respectively. Mean values for the EMG recordings of muscle bands with trigger points versus the normal muscle using the spike counting method were 31.81 and 8.75 respectively. Both results were statistically compared using student's t-test. The motorunit electrical activity of the bands with trigger points was found to be significantly higher (p less than or equal to 0.001) than that of the normal muscle.

Action Potentials↗
PubMed1986

Pressure threshold meter: its use for quantification of tender spots.

The pressure threshold meter (PTM) and its use for evaluation of tender spots and trigger points are described. Pressure threshold is the minimum pressure inducing pain or discomfort. The PTM consists of a force gauge (11 kg range) to which a rubber disc with lcm2 surface is attached. This surface has been proven adequate for quantification of deep tenderness in soft tissues. Normal threshold values were established in 50 volunteers, 24 men and 26 women, at nine different sites frequently affected by trigger points, including the trapezius, supraspinatus, infraspinatus, teres major, lumbar paraspinals (2 sites), gluteus and pectoralis muscles. The deltoid, where muscle sensitivity is usually normal, was used as a reference. PTM is used clinically for quantification of tenderness for medicolegal purposes, but primarily to prove the presence of trigger points to patients and health professionals. Reaction to various forms of treatment such as physiotherapy and drugs can be assessed quantitatively. When trigger point injections are properly administered to affected areas, pressure threshold measurements usually increase by 4 kg/cm2. Failure to increase the reading indicates that the injection was incomplete and the procedure should be repeated. The PTM can be used for monitoring tenderness, inflammation, arthritis activity, and fibrositis.

Equipment Design↗
PubMed2005

Persistent myalgia following whiplash.

Persistent myalgia following whiplash is commonly considered the result of poor psychosocial status, illness behavior, or failing coping skills. However, there is much evidence that persistent myalgia may be due to neurophysiologic mechanisms involving peripheral and central sensitization. Myofascial trigger points may play a crucial role in maintaining sensitization. Recent research suggests that the chemical environment of myofascial trigger points is an important factor. Several consequences are reviewed when central pain mechanisms and myofascial trigger points are included in the differential diagnosis and in the management of patients with persistent pain following whiplash.

Chronic Disease↗
PubMed2001

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

OBJECTIVE: 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. DESIGN: 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. RESULTS: 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). CONCLUSIONS: 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.

Animals↗
PubMed2006

A double-blind, controlled study of botulinum toxin A in chronic myofascial pain.

BACKGROUND: Recent studies have reported a potential analgesic effect of botulinum toxin A (BTXA) in musculoskeletal pain. The present double-blind, randomized, placebo-controlled, parallel clinical trial studied the effect of BTXA on pain from muscle trigger points and on EMG activity at rest and during voluntary contraction. METHODS: Thirty patients with trigger points in the infraspinatus muscles received either 50 units/0.25 mL of BTXA or 0.25 mL of isotonic saline. Baseline measures were determined during a run-in period of 1 week. Outcome measures including local and referred spontaneous pain, pain detection and tolerance thresholds to mechanical pressure, and shoulder movement were assessed at 3 and 28 days after injection. The interference pattern of the EMG during maximal voluntary effort of infraspinatus muscle was recorded and a standardized search for spontaneous electrical motor endplate activity at the trigger points was performed before and 28 days after BTXA or saline injection. RESULTS: BTXA reduced motor endplate activity and the interference pattern of EMG significantly but had no effect on either pain (spontaneous or referred) or pain thresholds compared with isotonic saline. CONCLUSIONS: The results do not support a specific antinociceptive and analgesic effect of botulinum toxin A.

Analgesics↗
PubMed2002

Effect of botulinum toxin on endplate noise in myofascial trigger spots of rabbit skeletal muscle.

OBJECTIVE: 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. DESIGN: 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. RESULTS: 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. CONCLUSIONS: 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.

Acetylcholine↗
PubMed2006

Efficacy and safety of a single botulinum type A toxin complex treatment (Dysport) for the relief of upper back myofascial pain syndrome: results from a randomized double-blind placebo-controlled multicentre study.

Botulinum type A toxin (BoNT-A) has antinociceptive and muscle-relaxant properties and may help relieve the symptoms of myofascial pain syndrome. In this study we evaluated the efficacy and tolerability of BoNT-A (Dysport) in patients with myofascial pain syndrome of the upper back. We conducted a prospective, randomized, double-blind, placebo-controlled, 12-week, multicentre study. Patients with moderate-to-severe myofascial pain syndrome affecting cervical and/or shoulder muscles (10 trigger points, disease duration 6-24 months) were randomized to Dysport or saline. Injections were made into the 10 most tender trigger points (40 units per site). The primary outcome was the proportion of patients with mild or no pain at week 5. Secondary outcomes included changes in pain intensity and the number of pain-free days per week. Tolerability and safety were also assessed. At week 5, significantly more patients in the Dysport group reported mild or no pain (51%), compared with the patients in the placebo group (26%; p=0.002). Compared with placebo, Dysport resulted in a significantly greater change from baseline in pain intensity during weeks 5-8 (p<0.05), and significantly fewer days per week without pain between weeks 5 and 12 (p=0.036). Treatment was well tolerated, with most side effects resolving within 8 weeks. In conclusion, in patients with upper back myofascial pain syndrome, injections of 400 Ipsen units of Dysport at 10 individualised trigger points significantly improved pain levels 4-6 weeks after treatment. Injections were well tolerated.

Adolescent↗
PubMed1994

Myofascial pain.

MFP is a regional muscle pain disorder characterized by localized muscle tenderness and pain and is the most common cause of persistent regional pain. The affected muscles may also display an increased fatiguability, stiffness, subjective weakness, pain on movement and slightly restricted range of motion that is unrelated to joint restriction. MFP is frequently overlooked as a diagnosis because it is often accompanied by signs and symptoms in addition to pain, coincidental pathological conditions, and behavioural and psychosocial problems. Chronic pain characteristics often precede or follow the development of MFP. Evaluation of MFP includes locating the trigger points and muscles involved as well as recognition of the contributing factors. Management of the syndrome naturally follows with muscle exercises, therapy to the trigger points, and reduction of all the contributing factors. The short-term goal is to restore the muscle to normal length and posture and full joint range of motion with exercises and trigger point therapy. The long-term goals include reducing the symptoms and their negative effects while helping the patient return to normal function without the need for future health care. The difficulty in managing MFP lies in the critical need to match the level of complexity of the management programme with the complexity of the patient's situation. Failure to address the entire problem, through a team approach if needed, may lead to failure to resolve the pain and perpetuation of a chronic pain syndrome.

Fibromyalgia↗
PubMed1996

[Diagnosis and treatment of myofascial pain].

Myofascial pain (MFP) is a regional muscle pain disorder characterized by localized muscle tenderness and pain and is the most common cause of persistent regional pain. MFP is frequently overlooked as a diagnosis because it is often accompanied by signs and symptoms in addition to pain, coincidental pathology conditions, and behavioral and psychosocial problems. Evaluation of myofascial pain includes locating the trigger points and muscles involved as well as recognition of these contributing factors. Management of the syndrome follows with palliative care, splint therapy, muscle exercises, therapy to the trigger points, and behavioral therapy that depends on complexity of the case. The short term goals is to restore the muscle tot normal length, posture, and full joint range of motion with exercises and trigger point therapy. The long term goals include reducing the symptoms and their negative effects while helping the patient return to normal function without need for further health care. The difficulty in managing MFP lies in the critical need to match the level of complexity of the management program with the complexity of the patient. Failure to address the entire problem through a team approach if needed, may lead to failure to resolve the pain and perpetuation of a chronic pain syndrome.

Chronic Disease↗
PubMed1987

Myofascial pain syndrome.

Myofascial pain, a general descriptive term, is applied to painful sensations that extend along one or more skeletal muscles and their fascia. Trigger points, discrete hyperesthetic areas within the muscle and its fascia, are characteristically found in myofascial pain. On the other hand, myofascial pain syndrome is a painful condition characterized by the presence of trigger points, local and referred pain, tenderness, referred autonomic phenomena as well as anxiety and depression. Patients affected by myofascial pain, trigger points, or myofascial pain syndrome, represent a significant population group requesting services in the offices of general practitioners, orthopaedic surgeons, and physicians treating musculoskeletal disorders.

Adult↗
PubMed2006

Are tender point injections beneficial: the role of tonic nociception in fibromyalgia.

Characteristic symptoms of fibromyalgia syndrome (FM) include widespread pain, fatigue, sleep abnormalities, and distress. FM patients show psychophysical evidence for mechanical, thermal, and electrical hyperalgesia. To fulfill FM criteria, the mechanical hyperalgesia needs to be widespread and present in at least 11 out of 18 well-defined body areas (tender points). Peripheral and central abnormalities of nociception have been described in FM and these changes may be relevant for the increased pain experienced by these patients. Important nociceptor systems in the skin and muscle seem to undergo profound changes in FM patients by yet unknown mechanisms. These changes may result from the release of algesic substances after muscle or other soft tissue injury. These pain mediators can sensitize important nociceptor systems, including the transient receptor potential channel, vanilloid subfamily member 1 (TRPV1), acid sensing ion channel (ASIC) receptors, and purino-receptors (P2X3). Subsequently, tissue mediators of inflammation and nerve growth factors can excite these receptors and cause substantial changes in pain sensitivity. FM pain is widespread and does not seem to be restricted to tender points (TP). It frequently comprises multiple areas of deep tissue pain (trigger points) with adjacent much larger areas of referred pain. Analgesia of areas of extensive nociceptive input has been found to provide often long lasting local as well as general pain relief. Thus interventions aimed at reducing local FM pain seem to be effective but need to focus less on tender points but more on trigger points (TrP) and other body areas of heightened pain and inflammation.

Botulinum Toxins↗
PubMed1998

[Myofascial pain syndrome--frequent occurrence and often misdiagnosed].

Myofascial pain syndrome (MPS) is a very common localized--sometimes also polytopic--painful musculoskeletal condition associated with trigger points, for which, however, diagnostic criteria established in well-designed studies are still lacking. These two facts form the basis for differentiating between MPS and the fibromyalgia syndrome. The difference between trigger points (MPS) and tender points (fibromyalgia) is of central importance--not merely in a linguistic sense. A knowledge of the signs and symptoms typically associated with a trigger point often obviates the need for time-consuming and expensive technical diagnostic measures. The assumption that many cases of unspecific complaints affecting the musculoskeletal system may be ascribed to MPS makes clear the scope for the saving of costs.

Adult↗
PubMed1986

Muscle tissue oxygen pressure in primary fibromyalgia.

Trigger points in painful muscle are a characteristic sign in patients with primary fibromyalgia. The MDO oxygen electrode was used to evaluate oxygenation in the subcutaneous tissue and in trigger points in the trapezius and brachioradial muscles. Ten patients and 8 normal controls were studied. The results in the patients were abnormal, with scattered or slalom-slope histograms, indicating low tissue oxygenation. The controls were normal, except in one case. The conclusion is that in patients with primary fibromyalgia, the muscle oxygenation is abnormal or low, at least in the trigger point area of the muscles.

Adult↗
PubMed1987

Pressure algometry over normal muscles. Standard values, validity and reproducibility of pressure threshold.

Pressure threshold is the minimal pressure (force) which induces pain. The pressure threshold meter (PTM) is a force gauge with a rubber disc of 1 cm2 surface. The instrument has been proven to be useful in clinical practice for quantification of deep muscle tenderness. Trigger points, fibrositis, myalgic spots, activity of arthritis as well as assessment of sensitivity to pain can be diagnosed by PTM. This study therefore established standards for pressure threshold as well as the reproducibility and validity of measurement in 24 male and 26 female normal volunteers at 9 sites. Muscles frequently afflicted by trigger points were examined. The deltoid was chosen as a reference since it is rarely a site for trigger points. Comparison of corresponding muscles on opposite sides failed to demonstrate significant differences (except for 1 muscle in females). These identical results obtained over muscles of opposite sides proved the excellent reproducibility and validity of pressure threshold measurement. Results serve as a reference for clinical diagnosis of abnormal tenderness and for documentation of treatment results. The sensitivity of individual muscles varies. Therefore the results presented should be kept in mind when diagnosis of pathological tenderness by palpation is attempted.

Adult↗
PubMed2005

Effect of dry needling of gluteal muscles on straight leg raise: a randomised, placebo controlled, double blind trial.

OBJECTIVES: To use a randomised, double blind, placebo controlled trial to establish the effect on straight leg raise, hip internal rotation, and muscle pain of dry needling treatment to the gluteal muscles in athletes with posterior thigh pain referred from gluteal trigger points. METHODS: A randomised, double blind, placebo controlled trial of 59 male runners was performed during the 2002 Australian Rules football season. Subjects were thoroughly screened and had magnetic resonance imaging of their hamstring muscles to exclude local pathology. The inclusion criterion was reproduction of recognisable posterior thigh pain with the application of digital pressure to the gluteal trigger points. Subjects randomly received either therapeutic or placebo needle treatment on one occasion at their gluteal trigger points. Range of motion and visual analogue scale data were collected immediately before, immediately after, 24 hours after, and 72 hours after the intervention. Range of motion was measured with passive straight leg raise and hip internal rotation. Visual analogue scales were completed for hamstring and gluteal pain and tightness at rest and during a running task. RESULTS: Magnetic resonance imaging scans revealed normal hamstring musculature in most subjects. Straight leg raise and hip internal rotation remained unchanged in both groups at all times. Visual analogue scale assessment of hamstring pain and tightness and gluteal tightness after running showed improvements immediately after the intervention in both groups (p = 0.001), which were maintained at 24 and 72 hours. The magnitude of this improvement was the same for therapeutic and placebo interventions. Resting muscle pain and tightness were unaffected. CONCLUSIONS: Neither dry needling nor placebo needling of the gluteal muscles resulted in any change in straight leg raise or hip internal rotation. Both interventions resulted in subjective improvement in activity related muscle pain and tightness. Despite being commonly used clinical tests in this situation, straight leg raise and hip internal rotation are not likely to help the therapist assess response to treatment. Patient reports of response to such treatment are better indicators of its success. The mechanisms by which these responses occur and the reasons for the success of the placebo needling treatment are areas for further investigation.

Acupuncture Therapy↗