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Chiropractic Management of Myofascial Trigger Points and Myofascial Pain Syndrome: A Systematic Review of the Literature

      Abstract

      Objectives

      Myofascial pain syndrome (MPS) and myofascial trigger points (MTrPs) are important aspects of musculoskeletal medicine, including chiropractic. The purpose of this study was to review the most commonly used treatment procedures in chiropractic for MPS and MTrPs.

      Methods

      The Scientific Commission of the Council on Chiropractic Guidelines and Practice Parameters (CCGPP) was charged with developing literature syntheses, organized by anatomical region, to evaluate and report on the evidence base for chiropractic care. This article is the outcome of this charge. As part of the CCGPP process, preliminary drafts of these articles were posted on the CCGPP Web site www.ccgpp.org (2006-8) to allow for an open process and the broadest possible mechanism for stakeholder input. PubMed, Excerpta Medica Database, Cumulative Index to Nursing and Allied Health Literature, and databases for systematic reviews and clinical guidelines were searched. Separate searches were conducted for (1) manual palpation and algometry, (2) chiropractic and other manual therapies, and (3) other conservative and complementary/alternative therapies. Studies were screened for relevance and rated using the Oxford Scale and Scottish Intercollegiate Guidelines Network rating system.

      Results

      A total of 112 articles were identified. Review of these articles resulted in the following recommendations regarding treatment: Moderately strong evidence supports manipulation and ischemic pressure for immediate pain relief at MTrPs, but only limited evidence exists for long-term pain relief at MTrPs. Evidence supports laser therapy (strong), transcutaneous electrical nerve stimulation, acupuncture, and magnet therapy (all moderate) for MTrPs and MPS, although the duration of relief varies among therapies. Limited evidence supports electrical muscle stimulation, high-voltage galvanic stimulation, interferential current, and frequency modulated neural stimulation in the treatment of MTrPs and MPS. Evidence is weak for ultrasound therapy.

      Conclusions

      Manual-type therapies and some physiologic therapeutic modalities have acceptable evidentiary support in the treatment of MPS and TrPs.

      Key Indexing Terms

      Ever since the seminal work of Travell and Rinzler
      • Travell J
      • Rinzler S
      The myofascial genesis of pain.
      in 1952, the role of myofascial trigger points (TrPs) in myofascial pain syndrome (MPS) has become an accepted part of musculoskeletal clinical practice. Along with Simons,
      • Travell J
      • Simons DG
      Myofascial pain and dysfunction: the trigger point manual.
      Travell first identified the importance of myofascial pain and its localization in what they termed trigger points, providing the first classification of diagnostic criteria for TrPs. They also provided detailed maps of the pain referral patterns from TrPs in all the muscles of the body. Myofascial pain syndrome is currently thought to be the leading diagnosis among pain management specialists
      • Harden RN
      • Bruehl SP
      • Gass S
      • Niemiec C
      • Barbick B
      Signs and symptoms of the myofascial pain syndrome: a national survey of pain management providers.
      and the leading diagnosis in pain patients reporting to general practitioners.
      • Skootsky SA
      • Jaeger B
      • Oye RK
      Prevalence of myofascial pain in general internal medicine.
      Interest in myofascial tenderness extends throughout the history of chiropractic. It might be said that local paraspinal tenderness, as part of the manifestations of the “subluxation,” was a central feature of chiropractic thinking from its inception. Arguably, the work of Ray Nimmo
      • Nimmo RL
      The development of chiropractic through the perspective of Dr. Raymond Nimmo [videorecording].
      • Nimmo RL
      The receptor-tonus method.

      Nimmo RL. The receptor-tonus method: directory 1962. Self-published.

      represents the earliest and perhaps still most established thinking on this topic among chiropractors. Cohen and Gibbons
      • Cohen JH
      • Gibbons RW
      • Raymond L
      Nimmo and the evolution of trigger point therapy, 1929-1986.
      describe his work as “a conceptual leap from moving bones to working with muscles that move bones.” Schneider
      • Schneider M
      Receptor-tonus technique assessment.
      • Schneider M
      The collected writings of Nimmo and Vannerson: pioneers of chiropractic trigger point therapy.
      has provided a collection and review of all of Nimmo's works. Nimmo's explanations in the 1950s of the pathophysiology of TrPs are still regarded as accurate and highly sophisticated.
      Other chiropractic authors who have written on this topic include Schneider,
      • Schneider M
      Receptor-tonus technique assessment.
      • Schneider M
      The collected writings of Nimmo and Vannerson: pioneers of chiropractic trigger point therapy.
      • Schneider MJ
      Snapping hip syndrome in a marathon runner: treatment by manual trigger point therapy—a case study.
      • Schneider M
      Tender points/fibromyalgia vs trigger points/myofascial pain syndrome: a need for clarity in terminology and differential diagnosis.
      Perle,
      • Perle SM
      Understanding trigger points: key to relieving myotogenous pain.
      • Perle SM
      Myofascial trigger points.
      Hains,
      • Hains G
      Locating and treating low back pain of myofascial origin by ischemic compression.
      • Hains G
      Chiropractic management of shoulder pain and dysfunction of myofascial origin using ischemic compression techniques.
      and Hammer,
      • Hammer W
      Functional soft tissue examination & treatment by manual methods.
      whose seminal textbook is now in its third printing. There are also numerous case reports and technical reports relating to various soft tissue techniques in chiropractic. In the field of MPS, chiropractic is generally regarded as one of the complementary and alternative medical (CAM) therapies. The CAM therapies are quite commonly used in the treatment of myofascial pain and TrPs,
      • Harris RE
      • Clauw DJ
      The use of complementary medical therapies in the management of myofascial pain disorders.
      and there is considerable overlap between chiropractic approaches and CAM therapies in this field.

      Methods

      The search strategy for this review was constrained by the need to identify only those studies of chiropractic treatments (manual therapy and other conservative therapies) that were not directed at clinical complaints associated with any of the specific body regions that have been designated as other reviews in the Council on Chiropractic Guidelines and Practice Parameters (CCGPP) process. In other words, no study was selected of the effect of a chiropractic treatment specifically indicated for back pain, neck pain, upper limb pain (shoulder, elbow, wrist), and lower limb pain (hip, knee, ankle, and foot) of any kind (ie, for any category of diagnosis). Only studies of chiropractic treatments for MPS and TrPs were considered. Therefore, the inclusion criteria for this search were as follows: manual therapies, trigger points, myofascial pain syndrome (MeSH headings: musculoskeletal manipulations, myofascial pain syndrome [not exploded to temporomandibular joint]), conservative therapies, laser, acupuncture, ultrasound (US), electrotherapy, naturopathy; 1965 to 2007; English, German; human studies.
      After the primary search was conducted, a number of secondary searches were conducted based upon “related links,” especially emphasizing systematic or clinical reviews, randomized clinical trials, and conservative treatments (vs musculoskeletal manipulations only), as well as searches of additional works by the authors identified in the primary search. Finally, citation reviews were conducted manually to identify any additional suitable studies.
      This search was conducted in the PubMed; Cumulative Index to Nursing and Allied Health Literature; Index to Chiropractic Literature (ICL); Manual, Alternative, and Natural Therapy System (MANTIS); Excerpta Medica Database; National Guidelines Clearinghouse; Database of Abstracts of Reviews of Effects; and Turning Research Into Practice databases. Selected publications were rated on the Oxford Rating Scale
      • Phillips B
      • Ball C
      • Sackett D
      • Badenoch D
      • Straus S
      • Haynes B
      • Dawes M
      Levels of evidence.
      • Sackett DL
      • Straus SE
      • Richardson
      • et al.
      Evidence-based medicine: how to practice and teach EBM.
      as well as the Scottish Intercollegiate Guidelines Network (SIGN) Checklist (Fig 1).
      Fig 1Rating scales for included studies.
      A. The Oxford Rating Scale.
      • Phillips B
      • Ball C
      • Sackett D
      • Badenoch D
      • Straus S
      • Haynes B
      • Dawes M
      Levels of evidence.
      • Sackett DL
      • Straus SE
      • Richardson
      • et al.
      Evidence-based medicine: how to practice and teach EBM.
      1a: Systematic review, with homogeneity of RCT’s.
      1b: Individual RCT with narrow confidence interval.
      1c: All or none.
      2a: Systematic review, with homogeneity of cohort studies.
      2b: Individual cohort study (including low quality RCT; eg <80% follow-up).
      2c: “Outcomes Research”; Ecological studies.
      3a: Systematic review with homogeneity of case-control studies.
      3b: Individual case-control study.
      4: Case-series (and poor quality cohort and case-control studies).
      5: Expert opinion without explicit critical appraisal, or based on physiology, bench research or “first principles”.
      B. The SIGN Checklist.
       1. ++ = All or most methodological criteria have been fulfilled/bias has been maximally reduced.
       2. + = Some of the criteria have been fulfilled/bias has been somewhat reduced.
       3. − = Few or no criteria fulfilled/bias is clearly present.
      This review accepted all levels of published evidence for narrative description: clinical guidelines, systematic reviews, clinical trials, cohort or case series, case studies, and clinical reviews. For evidence rating, recommendations were constructed and rated according to the Oxford Rating Scale
      • Phillips B
      • Ball C
      • Sackett D
      • Badenoch D
      • Straus S
      • Haynes B
      • Dawes M
      Levels of evidence.
      • Sackett DL
      • Straus SE
      • Richardson
      • et al.
      Evidence-based medicine: how to practice and teach EBM.
      as follows:
      • Consistent level 1 studies
      • Consistent level 2 or 3 studies or extrapolations from level 1 studies
      • Level 4 studies or extrapolations from level 2 or 3 studies
      • Level 5 studies or troublingly inconsistent or inconclusive studies at any level

      Results

      Manual Therapies

      Systematic Reviews of Manual Therapies

      Two completed systematic reviews were identified.
      • Fernandez de las Penas C
      • Sohrbeck Campo M
      • Fernandez Carnero J
      • Miangolarra Page JC
      Manual therapies in myofascial trigger point treatment: a systematic review.
      • Rickards LD
      The effectiveness of non-invasive treatments for active myofascial trigger point pain: a systematic review of the literature.
      These reviews were rated (Oxford Scale) as 1a evidence with a 2+ quality rating on the SIGN Checklist.
      Fernandez de las Penas et al
      • Fernandez de las Penas C
      • Sohrbeck Campo M
      • Fernandez Carnero J
      • Miangolarra Page JC
      Manual therapies in myofascial trigger point treatment: a systematic review.
      used the following selection criteria for acceptable studies:“clinical or randomized controlled trials in which some form of manual therapy (strain/counterstrain, ischemic compression, transverse friction massage, spray and stretch, muscle energy technique) was used to treat (myofascial trigger points) MTrPs” (p29).
      Mobilization and manipulation were apparently not explicitly included. It should be noted that the criterion applied to the “clinical category” in this search was “MTrPs,” although MPS was referenced later in their review. No additional, more specific criteria related to clinical complaints in any of the body regions (ie, back pain, neck pain, limb pain, etc) were used. It would appear that this search strategy is consistent with the one devised for this review, as other CCGPP reviews dealt with the chiropractic management of pain complaints specific to these body regions.
      Fernandez de las Penas et al
      • Fernandez de las Penas C
      • Sohrbeck Campo M
      • Fernandez Carnero J
      • Miangolarra Page JC
      Manual therapies in myofascial trigger point treatment: a systematic review.
      identified 7 acceptable trials (SIGN = 2+/Oxford Scale ratings = 1b), 4 of which obtained a sufficiently high quality score (>5/10 on the Physiotherapy Evidence Database Scale).
      • Gam et al
        • Gam AN
        • Warming S
        • Larsen LH
        Treatment of myofascial trigger points with ultrasound combined with massage and exercise: a randomized controlled trial.
        (Physiotherapy Evidence Database score = 6/10)
      • Jaeger and Reeves
        • Jaeger B
        • Reeves JL
        Quantification of changes in myofascial trigger point sensitivity with the pressure algometer following passive stretch.
        (2/10)
      • Hanten et al
        • Hanten W
        • Olson S
        • Butts N
        • Nowicki A
        Effectiveness of a home program of ischemic pressure followed by sustained stretch for treatment of myofascial trigger points.
        (3/10)
      • Hong et al
        • Hong CZ
        • Chen YC
        • Pon CH
        • Yu J
        Immediate effects of various physical medicine modalities on pain threshold of an active myofascial trigger point.
        (6/10)
      • Hou et al
        • Hou CR
        • Tsai LC
        • Cheng KF
        • Chung KC
        • Hong CZ
        Immediate effects of various physical therapy modalities on cervical myofascial pain and trigger point sensitivity.
        (5/10)
      • Hanten et al
        • Hanten WP
        • Barret M
        • Gillespie-Plesko M
        • Jump KA
        • Olson SL
        Effects of active head retraction with retraction/extension and occipital release on the pressure pain threshold of cervical and scapular trigger points.
        (5/10)
      • Dardzinski et al
        • Dardzinski JA
        • Ostrov BE
        • Hamann LS
        Myofascial pain unresponsive to standard treatment. Successful use of strain and counterstrain technique in physical therapy.
        (1/10)
      The interventions used in these studies were as follows (number of studies in parentheses): spray and stretch (2), soft tissue massage (2), ischemic compression (2), occipital release exercises (1), strain/counterstrain (SCS) (1), and myofascial release (1). An important finding was:“Only 2 studies … test(ed) the specific efficacy (efficacy beyond placebo) of various manual therapies in the treatment of MPS (Gam et al
      • Gam AN
      • Warming S
      • Larsen LH
      Treatment of myofascial trigger points with ultrasound combined with massage and exercise: a randomized controlled trial.
      [massage] and Hanten et al
      • Hanten W
      • Olson S
      • Butts N
      • Nowicki A
      Effectiveness of a home program of ischemic pressure followed by sustained stretch for treatment of myofascial trigger points.
      [occipital release]). These studies found no difference between interventions” (p30).
      • Fernandez de las Penas C
      • Sohrbeck Campo M
      • Fernandez Carnero J
      • Miangolarra Page JC
      Manual therapies in myofascial trigger point treatment: a systematic review.
      Another important issue from this group of studies is the duration of treatment. Most of these studies (4) investigated only the immediate effects on pain and tenderness.
      • Jaeger B
      • Reeves JL
      Quantification of changes in myofascial trigger point sensitivity with the pressure algometer following passive stretch.
      • Hong CZ
      • Chen YC
      • Pon CH
      • Yu J
      Immediate effects of various physical medicine modalities on pain threshold of an active myofascial trigger point.
      • Hou CR
      • Tsai LC
      • Cheng KF
      • Chung KC
      • Hong CZ
      Immediate effects of various physical therapy modalities on cervical myofascial pain and trigger point sensitivity.
      • Hanten WP
      • Barret M
      • Gillespie-Plesko M
      • Jump KA
      • Olson SL
      Effects of active head retraction with retraction/extension and occipital release on the pressure pain threshold of cervical and scapular trigger points.
      One study investigated the short-term treatment effects of ischemic compression vs exercises over 5 treatments,
      • Hanten W
      • Olson S
      • Butts N
      • Nowicki A
      Effectiveness of a home program of ischemic pressure followed by sustained stretch for treatment of myofascial trigger points.
      whereas 2 investigated longer-term effects (6 months) of a course of, in one case, massage added to US therapy
      • Gam AN
      • Warming S
      • Larsen LH
      Treatment of myofascial trigger points with ultrasound combined with massage and exercise: a randomized controlled trial.
      and, in the other case, SCS in addition to exercises.
      • Dardzinski JA
      • Ostrov BE
      • Hamann LS
      Myofascial pain unresponsive to standard treatment. Successful use of strain and counterstrain technique in physical therapy.
      In both of the latter studies of a course of therapy, the manual therapy used (massage or SCS) was included among other therapies, making it impossible to identify the distinct contribution of the manual therapy to the reported outcomes.
      Fernandez de las Penas et al
      • Fernandez de las Penas C
      • Sohrbeck Campo M
      • Fernandez Carnero J
      • Miangolarra Page JC
      Manual therapies in myofascial trigger point treatment: a systematic review.
      conclude that there are very few randomized controlled studies (RCTs) of any type of manual therapy in the treatment of MTrP (MPS) and, as a result, “the hypothesis that manual therapies have specific efficacy beyond placebo in the management of MPS caused by MTrPs is neither supported or refuted by the research to date” (p33). They do acknowledge that there is some evidence for improvement in some groups within these trials and that this warrants further research.
      In Rickards'
      • Rickards LD
      The effectiveness of non-invasive treatments for active myofascial trigger point pain: a systematic review of the literature.
      review, the inclusion criteria included RCTs of a conservative (in this section: manual only) therapy for active TrPs, not latent TrPs, in which a patient-related pain outcome was used and in which an explicit diagnosis of TrP was made including at least local tenderness and a taut muscle band. Studies were rated on a 20-point scale; however, no cutoff score was used for inclusion. Rickards included the following studies: Chatchawan et al,
      • Chatchawan U
      • Thinkhamrop B
      • Kharmawan S
      • Knowles J
      • Eungpinichpong W
      Effectiveness of traditional Thai massage versus Swedish massage among patients with back pain associated with myofascial trigger points.
      Fernandes de las Penas et al,
      • Fernandez de las Penas C
      • Alonso-Blanco C
      • Fernandez-Carnero J
      • Miangolarra-Page JC
      The immediate effect of ischemic compression technique and transverse friction massage on tenderness of active and latent myofascial trigger points: a pilot study.
      Hanten et al,
      • Hanten WP
      • Barret M
      • Gillespie-Plesko M
      • Jump KA
      • Olson SL
      Effects of active head retraction with retraction/extension and occipital release on the pressure pain threshold of cervical and scapular trigger points.
      Hou et al,
      • Hou CR
      • Tsai LC
      • Cheng KF
      • Chung KC
      • Hong CZ
      Immediate effects of various physical therapy modalities on cervical myofascial pain and trigger point sensitivity.
      and Edwards and Knowles.
      • Edwards J
      • Knowles N
      Superficial dry needling and active stretching in the treatment of myofascial pain—a randomised controlled trial.
      For the purposes of the present review, the following comments apply to this group of studies: (1) The study of Chatchawan et al
      • Chatchawan U
      • Thinkhamrop B
      • Kharmawan S
      • Knowles J
      • Eungpinichpong W
      Effectiveness of traditional Thai massage versus Swedish massage among patients with back pain associated with myofascial trigger points.
      of massage therapies clearly identified the target group as chronic low back pain and would be included in the CCGPP review on low back pain. (2) The study of Fernandez de las Penas
      • Fernandez de las Penas C
      • Alonso-Blanco C
      • Fernandez-Carnero J
      • Miangolarra-Page JC
      The immediate effect of ischemic compression technique and transverse friction massage on tenderness of active and latent myofascial trigger points: a pilot study.
      is included below. (3) The studies of Hanten et al and Hou et al are included in the review by Fernandez de las Penas et al above. (4) Edwards and Knowles' trial
      • Edwards J
      • Knowles N
      Superficial dry needling and active stretching in the treatment of myofascial pain—a randomised controlled trial.
      did not include a manual therapy (only active stretching and dry needling were investigated). Therefore, for manual therapies, Rickards' review does not add anything substantial to the present review.
      A Cochrane Collaboration Protocol entitled “Non-invasive physical treatments of myofascial pain” (Kilkenny et al
      • Kilkenny MB
      • Deane K
      • Smith KA
      • Eyre S
      Non-invasive physical treatments of myofascial pain (protocol).
      ) was identified. This protocol currently contains no results. However, it was used as a source of additional references, particularly on published clinical trials and systematic reviews.

      Practice Guidelines on Manual Therapy

      The following practice guidelines were identified:
      • Institute for Clinical Systems Improvement (ICSI). Assessment and management of chronic pain. Bloomington (MN): Institute for Clinical Systems Improvement (ICSI); 2005 Nov. 77 p. No recommendation for physical (manual) therapies in the treatment of MPS or TrPs.
      • Work Loss Data Institute. Pain (chronic). Corpus Christi (TX): Work Loss Data Institute; 2006. 261 p. Myofascial pain syndrome, physical therapy: 14-21 days.

      RCTs of Manual Therapy

      In addition to Fernandez de las Penas et al,
      • Gam AN
      • Warming S
      • Larsen LH
      Treatment of myofascial trigger points with ultrasound combined with massage and exercise: a randomized controlled trial.
      our search identified 3 RCTs (Oxford Scale rating = 1b or 2b) of the effect of spinal manipulation on local paraspinal muscular tenderness in the dorsal spine (Terret and Vernon
      • Terrett AC
      • Vernon H
      Manipulation and pain tolerance. A controlled study of the effect of spinal manipulation on paraspinal cutaneous pain tolerance levels.
      [2+/2b]), cervical spine (Vernon et al
      • Vernon HT
      • Aker P
      • Burns S
      • Viljakaanen S
      • Short L
      Pressure pain threshold evaluation of the effect of spinal manipulation in the treatment of chronic neck pain: a pilot study.
      [2+/2b]), and lumbopelvic area (Cote et al
      • Cote P
      • Mior SA
      • Vernon H
      The short-term effect of a spinal manipulation on pain/pressure threshold in patients with chronic mechanical low back pain.
      [2+/2b]). All 3 studies investigated only the immediate effect of the interventions on local muscular pain thresholds (electrical stimulus in Terret and Vernon
      • Terrett AC
      • Vernon H
      Manipulation and pain tolerance. A controlled study of the effect of spinal manipulation on paraspinal cutaneous pain tolerance levels.
      and pressure stimulus in Vernon et al
      • Vernon HT
      • Aker P
      • Burns S
      • Viljakaanen S
      • Short L
      Pressure pain threshold evaluation of the effect of spinal manipulation in the treatment of chronic neck pain: a pilot study.
      and Cote et al
      • Cote P
      • Mior SA
      • Vernon H
      The short-term effect of a spinal manipulation on pain/pressure threshold in patients with chronic mechanical low back pain.
      ). Immediate and statistically significant increases in pain thresholds were found for spinal manipulation as compared with mobilization in the cervical and dorsal paraspinal muscles, but not in the lumbopelvic soft tissues.
      Vicenzino et al
      • Vicenzino B
      • Collins D
      • Wright A
      The initial effects of a cervical spine manipulative physiotherapy treatment on the pain and dysfunction of lateral epicondylalgia.
      (2+/1b) reported on the immediate effect of a cervical mobilization on pressure pain threshold (PPT) of tender points on the lateral epicondyle in patients with “tennis elbow.” Only the mobilization (described as “manipulation” in this study) resulted in statistically significant increases in lateral epicondyle PPTs vs placebo and control conditions.
      Greene et al
      • Greene C
      • Debias D
      • Helig D
      • Nicholas A
      • England K
      • Ehrenfeuchter W
      • Young W
      The effect of helium-neon laser and osteopathic manipulation on soft-tissue trigger points.
      (2+/1b) investigated the effect of 4 different treatments given 3 times over 3 days on skin resistance levels. Subjects with thoracic TrPs were randomized to receive osteopathic manipulative treatment (OMT), laser treatment, OMT plus laser, and sham laser. No significant differences in effects were noted between these groups.
      Atienza Meseguer et al
      • Atienza Meseguer A
      • Fernandez de las Penas C
      • Navarro-Poza JL
      • Rodriguez-Blanco C
      • Bosca Gandia JJ
      Immediate effects of the strain/counterstrain technique in local pain evoked by tender points in the upper trapezius muscle.
      (2+/1b) studied 54 subjects with trapezius TrP treated with classic SCS, modified SCS, and control. Both treatment groups showed immediate improvement in PPT vs controls, but not vs each other.
      Fryer and Hodgson
      • Fryer G
      • Hodgson L
      The effect of manual pressure release on myofascial trigger points in the upper trapezius muscle.
      (2+/1b) compared manual pressure release to sham myofascial release in 37 subjects with upper trapezius myofascial TrPs. A statistically significant increase in PPT was obtained immediately after the intervention in the manual pressure group vs controls that was found to be due to a change in tissue sensitivity.
      Fernandez-de-las-Penas et al
      • Fernandez de las Penas C
      • Alonso-Blanco C
      • Fernandez-Carnero J
      • Miangolarra-Page JC
      The immediate effect of ischemic compression technique and transverse friction massage on tenderness of active and latent myofascial trigger points: a pilot study.
      (2+/1b) compared ischemic compression to transverse friction massage in 40 subjects with myofascial TrPs in the upper trapezius muscle. Both groups obtained significant improvement in PPT within 2 minutes. No difference was found between the groups.

      Conclusion: RCTs

      A total of 14 RCTs were retrieved. Quality scores ranged widely for the 7 trials reviewed by Fernandes de las Penas et al.
      • Fernandez de las Penas C
      • Sohrbeck Campo M
      • Fernandez Carnero J
      • Miangolarra Page JC
      Manual therapies in myofascial trigger point treatment: a systematic review.
      Ten of 14 trials we identified involved only immediate changes in TrP or tender point ratings. Two other trials reported outcomes for short courses of treatments over 3 to 5 days,
      • Hanten W
      • Olson S
      • Butts N
      • Nowicki A
      Effectiveness of a home program of ischemic pressure followed by sustained stretch for treatment of myofascial trigger points.
      • Greene C
      • Debias D
      • Helig D
      • Nicholas A
      • England K
      • Ehrenfeuchter W
      • Young W
      The effect of helium-neon laser and osteopathic manipulation on soft-tissue trigger points.
      whereas 2 others reported outcomes at 6 months.
      • Gam AN
      • Warming S
      • Larsen LH
      Treatment of myofascial trigger points with ultrasound combined with massage and exercise: a randomized controlled trial.
      • Dardzinski JA
      • Ostrov BE
      • Hamann LS
      Myofascial pain unresponsive to standard treatment. Successful use of strain and counterstrain technique in physical therapy.
      The outcomes of the “immediate” trials can be summarized as demonstrating effectiveness in reducing tenderness for spinal manipulation (2 of 3 trials), spray and stretch (2 trials), ischemic compression (3 trials), transverse friction massage (1 trial), and SCS (1 trial). One trial of mobilization failed to show any significant changes in tenderness scores vs controls. It would appear that there is moderately strong evidence to support the use of some manual therapies in the immediate relief of TrP tenderness.
      The 2 trials of short-term effects (3-5 days) demonstrated the effectiveness of osteopathic manipulation and ischemic compression, respectively, in reducing TrP tenderness. One long-term trial reported that SCS demonstrates clinically important changes in TrP tenderness and general pain over 6 months, whereas the other showed that massage produced limited effect. It would appear that there is only limited evidence to support the use of manual therapies over longer courses of treatments in the management of TrPs and MPS.

      Case Reports of Manual Therapy

      Twenty-six case reports in the chiropractic literature were identified from ICL or MANTIS (Appendix A). These reports covered TrP treatments in patients with hand pain, low back pain due to a TrP in the quadratus lumborum muscle, wrist pain, fibromyalgia, upper quarter syndrome, MPS, and general TrPs.

      Clinical Reviews of Manual Therapy

      Up-to-date clinical reviews
      • Hong CZ
      Myofascial pain therapy.
      • Gerwin RD
      A review of myofascial pain and fibromyalgia—factors that promote their persistence.
      • Alvarez DJ
      • Rockwell PG
      Trigger points: diagnosis and management.
      • Simons DG
      Understanding effective treatments of myofascial trigger points.
      • Harden RN
      Muscle pain syndromes.
      • Lavelle ED
      • Lavelle W
      • Smith HS
      Myofascial trigger points.
      by noted experts in the field of myofascial pain have endorsed the use of a variety of manual therapies in the treatment of TrPs and MPS. These are classed as level 5 (Oxford Rating) evidence.
      Harden
      • Harden RN
      Muscle pain syndromes.
      notes that the principle aims of therapy for MPS are relief of pain and inflammation, prevention of further injury, reducing spasm, correcting abnormal postures, and improving circulation. He endorses the following therapeutic modalities for accomplishing these aims:
      • In the acute stage:
        • Ice
        • Iontophoresis
        • US
        • splinting
      • Postural and ergonomic education
      • Massage
      • Myofascial release
      • Exercises and postural correction
      • Laser therapy: efficacy undetermined
      • Acupuncture: efficacy undetermined
      Hong
      • Hong CZ
      Myofascial pain therapy.
      recommends that the first principle of treatment of MPS is the identification and treatment of the presumed primary lesion (section 1). Only after this has been done, and if there is persistence of pain from the active TrPs, should direct treatment to the TrPs be performed. Hong suggests that, at this point in the therapeutic process, release of muscle tightness is the first objective. He identifies 7 steps in the treatment process for the active TrPs themselves:
      • i.
        Pain recognition: treating the active TrPs and not the latent ones.
      • ii.
        Identify the key TrP: Among active TrPs, one will be the most painful and most provocative of referred pain.
      • iii.
        Conservative vs aggressive treatment: This principle applies to the treatment of the primary lesion as well as the key TrP. Treatment should begin with what he describes as “non-invasive treatment including physiotherapy” and progress toward more invasive forms of therapy.
      • iv.
        Acute vs chronic TrPs: Distinguishing these helps guide therapy in the acute vs chronic stages of pain.
      • v.
        Superficial vs deep TrPs: Different therapeutic modalities are needed the more deeply located is the TrP.
        • a.
          Superficial: deep pressure massage.
        • b.
          Deep: stretch, US, laser, acupuncture, acupressure, or local injection.
      • vi.
        Individual preference: Each patient may have levels of comfort and familiarity with various forms of treatment that should then be tailored to this need.
      • vii.
        Other considerations: cost, time, etc.
      Hong places considerable importance on manual therapies for TrPs. He indicates the following as important aspects of manual therapy (p40):
      • -
        Stretching of shortened muscles (or taut band)
      • -
        Improving local circulation
      • -
        Counterirritation
      • -
        Other reflex effects
      Gerwin
      • Gerwin RD
      A review of myofascial pain and fibromyalgia—factors that promote their persistence.
      also endorses the treatment protocol that separately addresses therapies for the local TrP vs therapies for the perpetuating factors. In the former category, he specifically endorses manual TrP compression for focal TrP release, followed by myofascial release techniques for local stretching and then “therapeutic stretch” for the longer-range elongation of the body segments. In the case of perpetuating factors, he includes correction of postural faults as well as joint dysfunction. This should be followed by an active program of physical conditioning, stretching, and endurance, including preventative strategies. Unfortunately, no studies were provided as evidence for this approach.
      Simons
      • Simons DG
      Understanding effective treatments of myofascial trigger points.
      reviews the mechanisms of TrP formation and perpetuation to guide the appropriate treatment approach. The therapies endorsed in his review are as follows:
      • Postisometric relaxation and release
      • Trigger point (manual) pressure release
      • Combinations of the above 2 therapies
      • Trigger point massage
      Only the work of Lewit
      • Lewit K
      Post-isometric relaxation in combination with other methods of muscular facilitation and inhibition.
      is cited as support for this approach. Other noninvasive therapies that Simons merely mentions as additional to the approach described above include facilitatory techniques, acupuncture, SCS, microcurrent, US, and laser.
      Alvarez and Rockwell's
      • Alvarez DJ
      • Rockwell PG
      Trigger points: diagnosis and management.
      review only provides a list of noninvasive treatment modalities that include acupuncture, osteopathic manual medicine techniques [sic], massage, acupressure, US, heat, ice, diathermy, transcutaneous electrical nerve stimulation (TENS), and “spray and stretch” techniques. For these modalities, no clinical trial evidence was provided. The only support was a reference to the authoritative work described in Travel and Simons'
      • Travell J
      • Simons DG
      Myofascial pain and dysfunction: the trigger point manual.
      manual.
      Lavelle et al
      • Lavelle ED
      • Lavelle W
      • Smith HS
      Myofascial trigger points.
      endorse the following treatments as efficacious: spray and stretch, TENS, physical therapy, and massage.

      Critique of Clinical Reviews

      Manual Therapies

      All 6 reviews from within the last 5 years endorsed manual therapies for TrP treatment in MPS. None of these reviews provided a single reference to a clinical trial to support this position. None of the 11 trials reviewed above was cited in any of these reviews. As such, there is discordance, even at the level of renowned experts' reviews, between the apparent consensus on the use and types of manual therapies in treating TrPs vs the evidence from the published literature.

      Other therapies

      Only Harden
      • Harden RN
      Muscle pain syndromes.
      cites the clinical trial of Esenyel et al
      • Esenyel M
      • Caglar N
      • Aldemir T
      Treatment of myofascial pain.
      (US + stretching vs dry needling + stretching vs stretching alone) and the case series of Simunovic et al
      • Simunovic Z
      • Trobonjaca T
      • Trobonjaca Z
      Treatment of media land lateral epicondylitis—tennis and golfer's elbow—with low level laser therapy: a multicentre double-blind, placebo-controlled clinical study on 324 patients.
      (laser therapy) as clinical studies of these sorts of therapies as well as the review of laser therapy by Gam et al.
      • Gam AN
      • Warming S
      • Larsen LH
      Treatment of myofascial trigger points with ultrasound combined with massage and exercise: a randomized controlled trial.
      The other reviews provide no support in the form of any clinical study for their recommendation on noninvasive therapies for TrPs.

      Evidence Synthesis of Manual Therapies

      Table 1, Table 2 summarize the literature retrieved in this review.
      Table 1Literature review: all studies
      Study typeOxford levelNumber
      Systematic reviews1a2
      Systematic review protocols1
      Practice guidelines1a2
      RCTs1b11
      RCTs2b3
      Case series43 (Grobli; Anderson; Crawford)
      Case reports517
      Clinical reviews (selected: 2000-2005)56
      Table 2Literature review: randomized clinical trials of manual therapy for MPS or TrPs (all rated as Oxford 1b, unless otherwise noted as 2b)
      RCTTimeManual therapyOutcome
      Terret and Vernon, 1986 (2b)ImmediateSpinal manipulationSpinal manipulation > mobilization
      Jaeger and Reeves, 1986ImmediateSpray and stretchSignificant intragroup effects
      Greene et al, 19903 dOsteopathic manipulative therapyNo difference between OMT with or without laser and vs control
      Vernon et al, 1992 (2b)ImmediateSpinal manipulationSMT > control
      Hong et al, 1993ImmediateSpray and stretch, deep manual pressureDeep pressure massage was more effective than comparison modalities.
      Cote et al, 1994 (2b)ImmediateSpinal manipulationSpinal manipulation = control
      Hanten et al, 1997ImmediateManual mobilizationNo significant differences between mobilization, exercise, and control
      Gam et al, 19986 moMassageNo significant differences between massage with real or sham US or control
      Hanten et al, 20005 dIschemic compressionIschemic compression > exercise for pain and tenderness
      Dardzinski et al, 20006 moSCSClinically important intragroup changes
      Hou et al, 2002ImmediateIschemic compressionIschemic compression > control
      Fryer and Hodgson, 2005ImmediateManual pressure release vs sham controlManual pressure release > control
      Fernandez-de-las Penas et al, 2006ImmediateIschemic compression and transverse friction massageIschemic compression = transverse friction massage
      Atienza Meseguer et al, 2006ImmediateSCSSCS > control
      SMT, Spinal manipulation therapy.

      Clinical Practice Recommendations of Manual Therapies

      • 1.
        There is moderately strong evidence to support the use of some manual therapies in providing immediate pain relief at TrPs. The evidence level is B.
      • 2.
        There is only limited evidence to support the use of manual therapies over longer courses of treatment in the management of TrPs and MPS. The evidence level is C.

      Other Conservative Therapies

      Systematic Reviews of Other Conservative Therapies

      Two published reviews were identified for treatment methods other than manual therapies.
      • Rickards LD
      The effectiveness of non-invasive treatments for active myofascial trigger point pain: a systematic review of the literature.
      • Cummings TM
      • White AR
      Needling therapies in the management of myofascial trigger point pain: a systematic review.
      In Rickards'
      • Rickards LD
      The effectiveness of non-invasive treatments for active myofascial trigger point pain: a systematic review of the literature.
      review, the inclusion criteria included RCTs of a conservative therapy for active TrPs, not latent TrPs, in which a patient-related pain outcome was used and in which an explicit diagnosis of TrP was made including at least local tenderness and a taut muscle band. Studies were rated on a 20-point scale; however, no cutoff score was used for inclusion. It should be noted that no trials for acupuncture were included in this review (below). A total of 18 trials were included in this review (Table 3, Table 4, Table 5, Table 6). Rickards'
      • Rickards LD
      The effectiveness of non-invasive treatments for active myofascial trigger point pain: a systematic review of the literature.
      conclusions were based on the following schema:
      • Significant evidence: consistent findings in multiple high-quality RCTs
      • Moderate evidence: consistent findings in multiple lower-quality evidence and/or a single high-quality RCT
      • Limited evidence: a single low-quality RCT
      • Unclear evidence: inconsistent or conflicting results from multiple RCTs
      • No evidence: no evidence identified
      • Evidence of adverse effect: RCTs with lasting negative changes
      Table 3Studies of laser therapy from Rickards
      • Rickards LD
      The effectiveness of non-invasive treatments for active myofascial trigger point pain: a systematic review of the literature.
      (n = 6 studies)
      StudyTreatmentsOutcomes
      Gur et al
      • Gur A
      • Sarac AJ
      • Cevik R
      • Altindag O
      • Sarac S
      Efficacy of 904 nm gallium arsenide low level laser therapy in the management of chronic myofascial pain in the neck: a double-blind and randomized controlled trial.
      Laser vs placeboLaser > placebo
      Snyder-Mackler et al
      • Snyder-Mackler L
      • Barry AJ
      • Perkins AI
      • Soucek MD
      The effects of helium-neon laser irradiation on skin resistance and pain in patients with trigger points in the neck or back.
      Laser vs placeboLaser > placebo
      Ceccherelli et al
      • Ceccherelli F
      • Altafini L
      • Lo Castro G
      • Avila A
      • Ambrosio F
      • Giron GP
      Diode laser in cervical myofascial pain: a double-blind study versus placebo.
      Laser vs placeboLaser > placebo
      Hakguder et al
      • Hakguder A
      • Birtane M
      • Gurcan S
      • Kokino S
      • Turan FN
      Efficacy of low level laser therapy in myofascial pain syndrome: an algometric and thermographic evaluation.
      Laser and stretching vs placebo and stretchingLaser > placebo
      Ilbuldu et al
      • Ilbuldu E
      • Cakmak A
      • Disci R
      • Aydin R
      Comparison of laser, dry needling and placebo laser treatments in myofascial pain syndrome.
      Laser vs dry needling vs placeboLaser > dry needling
      Laser > placebo
      Altan et al
      • Altan L
      • Bingol U
      • Aydae M
      • Yurtkuran M
      Investigation of the effect of GA AS laser therapy on cervical myofascial pain syndrome.
      Laser + exercise + stretching vs placebo + exercise + stretchingLaser = placebo (other treatments thought to contribute to improvement)
      Table 4Studies of electrotherapy from Rickards
      • Rickards LD
      The effectiveness of non-invasive treatments for active myofascial trigger point pain: a systematic review of the literature.
      (n = 5 studies)
      StudyTreatmentsOutcomes
      Graff-Radford et al
      • Graff-Radford SB
      • Reeves JL
      • Jaeger B
      Management of head and neck pain: the effectiveness of altering perpetuating factors in myofascial pain.
      A: TENS mode AB > C, D > A, E (B = 100 Hz)
      B: TENS mode B
      C: TENS mode C
      D: TENS mode D
      E: Placebo TENS
      Farina et al
      • Farina S
      • Casarotto M
      • Bennelle M
      • Tinazzi M
      • Fiaschi A
      • Goldoni M
      • et al.
      A randomised controlled study on the effect of two different treatments (FREMS and TENS) in myofascial pain syndrome.
      FREMS vs TENSFREMS = TENS
      Hsueh et al
      • Hsueh TC
      • Cheng PT
      • Kuan TS
      • Hong CZ
      The immediate effectiveness of electrical nerve stimulation and electrical muscle stimulation on myofascial trigger points.
      A : Placebo electrotherapyTENS > EMS, placebo
      B : TENS
      C : EMS
      Ardic et al
      • Ardic F
      • Sarhus M
      • Topuz O
      Comparison of two different techniques of electrotherapy on myofascial pain.
      A: TENS + stretchingA = B > C
      B: EMS + stretching
      C: Stretching
      Tanrikut et al
      • Tanrikut A
      • Ozaras N
      • Ali Kaptan H
      • Guven Z
      • Kayhan O
      High voltage galvanic stimulation in myofascial pain syndrome.
      A: HVGS + exerciseA > B, C
      B: Placebo HVGS + exercise
      C: Exercise
      Table 5Studies of magnet therapy form Rickards
      • Rickards LD
      The effectiveness of non-invasive treatments for active myofascial trigger point pain: a systematic review of the literature.
      (n = 3 studies)
      StudyTreatmentsOutcomes
      Brown et al
      • Brown CS
      • Ling FW
      • Wan JY
      • Pilia AA
      Efficacy of static magnetic field therapy in chronic pelvic pain: a double-blind pilot study.
      Magnets vs placeboMagnets > placebo
      Smania et al
      • Smania N
      • Corato E
      • Fiaschi A
      • Pietropoli P Aglioti SM
      • Tinazzi M
      Repetitive magnetic stimulation: a novel approach for myofascial pain syndrome.
      A: RMSA > B > C
      B: TENS
      C: Placebo US
      Smania et al
      • Smania N
      • Corato E
      • Fiaschi A
      • Pietropoli P Aglioti SM
      • Tinazzi M
      Therapeutic effects of peripheral repetitive magnetic stimulation on myofascial pain syndrome.
      A: RMSA > B
      B: Placebo RMS
      RMS, Repetitive magnetic stimulation.
      Table 6Studies of US therapy from Rickards
      • Rickards LD
      The effectiveness of non-invasive treatments for active myofascial trigger point pain: a systematic review of the literature.
      (n = 4 studies)
      StudyTreatmentsOutcomes
      Gam et al
      • Gam AN
      • Warming S
      • Larsen LH
      Treatment of myofascial trigger points with ultrasound combined with massage and exercise: a randomized controlled trial.
      A: US + massage + exerciseA = B = C
      B: Placebo US + massage + exercise
      C: Control
      Maljesi et al
      • Maljesi J
      • Unalan H
      High power pain threshold ultrasound technique in the treatment of active myofascial trigger points: a randomized, double-blind case-control study.
      A: High-power USA > B
      B: Conventional US
      Lee et al
      • Lee JC
      • Lin Dt
      • Hong C
      The effectiveness of simultaneous thermotherapy with ultrasound and electrotherapy with combined AC and DC current on the immediate pain relief of myofascial trigger points.
      A: Placebo USC > A
      B: US
      C: Electrotherapy
      D: US + electrotherapy
      Esenyel et al
      • Esenyel M
      • Caglar N
      • Aldemir T
      Treatment of myofascial pain.
      A: US + stretchingA, B > C
      B: TrP injection + stretching
      C: Stretching
      Rickards' conclusions for each therapy were as follows:
      • Laser: Significant evidence that laser may be effective in the short term. Type, dose, and frequency of treatments require additional research.
      • TENS: Evidence (unqualified?) that TENS may be effective in providing immediate relief at TrPs.
      • Other electrotherapies: Limited evidence for the effectiveness of frequency modulated neural stimulation (FREMS), high-voltage galvanic stimulation (HVGS), electrical muscle stimulation (EMS), and interferential current (IFC).
      • US: Moderate evidence that US is no more effective than placebo.
      • Magnets: Preliminary evidence that magnets may be effective.
      It was noted that most trials involved either immediate or short-term effects and that much more research, especially on the longer-term effects, was needed.
      Cummings and White
      • Cummings TM
      • White AR
      Needling therapies in the management of myofascial trigger point pain: a systematic review.
      reviewed all trials up to 2000 of “Needling Therapies” for myofascial pain. Three of these trials involved what could be described as “standard” acupuncture typical of the type used by some chiropractors. This is distinguished from deep dry needling and any injection-type therapies that would not be standard chiropractic treatment approaches. For the present review, any trials that specifically identified one of the regional complaint areas in the CCGPP (ie, low back pain, neck pain) without specifying the treatment of TrPs were excluded (Table 7). Cummings and White
      • Cummings TM
      • White AR
      Needling therapies in the management of myofascial trigger point pain: a systematic review.
      concluded that marked improvements were demonstrated in most treatment groups. However, dry needling techniques alone did not appear to be superior to other treatments in the treatment of myofascial TrPs. As well, they could not find evidence for a specific efficacy of these techniques beyond placebo. They called for more placebo-controlled trials.
      Table 7Studies of acupuncture therapy from Cummings and White
      • Cummings TM
      • White AR
      Needling therapies in the management of myofascial trigger point pain: a systematic review.
      (n = 3)
      StudyTreatmentsOutcomes
      Birch and Jamison
      • Birch S
      • Jamison RN
      Controlled trial of Japanese acupuncture for chronic myofascial neck pain: assessment of specific and nonspecific effects of treatment.
      (neck pain)
      A: Superficial acupuncture + heatAt 3 mo: A > B, C
      B: Wrong point superficial acupuncture
      C: NSAID
      Johansson et al
      • Johannson A
      • Wenneberg B
      • Wagersten C
      • Haraldson T
      Acupuncture in treatment of facial muscular pain.
      (facial pain or headache)
      A: AcupunctureAt 3 mo: A = B > C
      B: Occlusal splint
      C: No treatment control
      Kisiel and Lindh
      • Kisiel C
      • Lindh C
      Smartlindring med fysikalsk terapi och manuell akupnktur vid myofasciella nackoch skuldersmartor.
      (neck pain)
      A: Manual acupunctureAt 6 mo: A = B
      B: Physiotherapy
      IP, ;NSAID, nonsteroidal anti-inflammatory drug.
      A Cochrane Collaboration Protocol entitled “Non-invasive physical treatments of myofascial pain” (Kilkenny et al
      • Kilkenny MB
      • Deane K
      • Smith KA
      • Eyre S
      Non-invasive physical treatments of myofascial pain (protocol).
      ) was identified. This protocol currently contains no results. However, it was used as a source of additional references, particularly on published clinical trials and systematic reviews.

      RCTs of Other Conservative Therapies

      Both Rickards
      • Rickards LD
      The effectiveness of non-invasive treatments for active myofascial trigger point pain: a systematic review of the literature.
      and Cummings and White
      • Cummings TM
      • White AR
      Needling therapies in the management of myofascial trigger point pain: a systematic review.
      used specific inclusion and exclusion criteria that resulted in the exclusion of numerous studies, either because they were not RCTs or for various methodologic reasons. These excluded trials will not be listed or reviewed here, as that would both duplicate and undermine the methods and conclusions of these reviews. Several trials have been identified in the present search that either have been published since these reviews or were not identified at all in these reviews (probably because of the inclusion of MANTIS and ICL databases in the present search) in the following areas:

      Acupuncture

      There is some additional evidence that a course of deep acupuncture to TrPs is effective in the treatment of myofascial pain for up to 3 months (Table 8).
      Table 8Additional acupuncture trials
      StudyTreatmentsOutcomes
      Ceccherelli et al
      • Ceccherelli F
      • Tortora P
      • Nassimbeni C
      • Casale R
      • Gagliardi G
      • Giron G
      The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain.
      (neck pain)
      A: Somatic acupunctureAt 1 and 3 mo: A = B (both = positive effect on pain)
      B: Somatic acupuncture + auricular acupuncture
      Itoh et al
      • Itoh K
      • Katsumi Y
      • Kitakoji H
      Trigger point acupuncture treatment of chronic low back pain in elderly patients—a blinded RCT.
      (low back pain)
      A: Acupuncture at traditional pointsAt 3 mo: A > B, C (not statistically significant)
      B: Superficial acupuncture at TrPs
      C: Deep acupuncture at TrPs
      Ceccherelli et al
      • Ceccherelli F
      • Rigoni MT
      • Gagliardi G
      • Ruzzante L
      Comparison of superficial and deep acupuncture in the treatment of lumbar myofascial pain: a double-blind randomized controlled study.
      (low back pain)
      A: Superficial acupuncture to TrPAt 3 mo: B > A
      B: Deep acupuncture to TrP
      Goddard et al
      • Goddard G
      • Karibe H
      • McNeill C
      • Villafuerte E
      Acupuncture and sham acupuncture reduce muscle pain in myofascial pain patients.
      (jaw pain)
      A: AcupunctureImmediately: A = B
      B: Sham acupuncture
      Ceccherelli et al
      • Ceccherelli F
      • Bordin M
      • Gagliardi G
      • Caravello M
      Comparison between superficial and deep acupuncture in the treatment of shoulder myofascial pain: a randomized and controlled study.
      (shoulder)
      A: Superficial acupuncture to TrPAt 1 and 3 mo: B > D
      B: Deep acupuncture to TrP

      Laser

      The study of Greene et al
      • Greene C
      • Debias D
      • Helig D
      • Nicholas A
      • England K
      • Ehrenfeuchter W
      • Young W
      The effect of helium-neon laser and osteopathic manipulation on soft-tissue trigger points.
      of laser vs osteopathic manipulation (OMT) alone vs OMT + laser vs sham laser to thoracic paraspinal muscle TrPs over 3 days involved measuring only local skin resistance. No measures of pain or tenderness response were made. This study would not have qualified for Rickards' review and does not, as well, for the present review.
      Olavi et al
      • Olavi A
      • Pekka G
      • Pertti K
      • Pekka P
      Effects of infrared laser therapy at treated and non-treated trigger points.
      compared infrared laser to placebo laser over various active TrPs located throughout the body. Pressure pain thresholds were measured immediately after and then 15 minutes after treatment. A statistically significant difference favoring the laser group was found, especially at 15 minutes.

      Electrotherapy

      No additional studies were retrieved.

      Exercise

      No additional studies not already included in Rickards
      • Rickards LD
      The effectiveness of non-invasive treatments for active myofascial trigger point pain: a systematic review of the literature.
      under “physical therapies” were retrieved.

      Spray and stretch

      The study of Hou et al
      • Hou CR
      • Tsai LC
      • Cheng KF
      • Chung KC
      • Hong CZ
      Immediate effects of various physical therapy modalities on cervical myofascial pain and trigger point sensitivity.
      was included in section 3 and was included in the reviews of both Fernandes de las Penas et al
      • Fernandez de las Penas C
      • Sohrbeck Campo M
      • Fernandez Carnero J
      • Miangolarra Page JC
      Manual therapies in myofascial trigger point treatment: a systematic review.
      and Rickards
      • Kilkenny MB
      • Deane K
      • Smith KA
      • Eyre S
      Non-invasive physical treatments of myofascial pain (protocol).
      under the category of manual therapy. This is because most treatment groups received ischemic compression with or without a variety of other physiologic therapies. One of these therapies was spray and stretch, making Hou et al
      • Hou CR
      • Tsai LC
      • Cheng KF
      • Chung KC
      • Hong CZ
      Immediate effects of various physical therapy modalities on cervical myofascial pain and trigger point sensitivity.
      the only published clinical trial to investigate this therapy. Hou et al found that the addition of spray and stretch to ischemic compression provided immediate benefit in reducing TrP sensitivity. There are no other published clinical trials of spray and stretch therapy for management of pain from TrPs. Notwithstanding this, it is often cited by clinical experts as a valuable treatment of TrPs.

      Ultrasound

      Srbely and Dickey
      • Srbely J
      • Dickey JP
      Stimulation of myofascial trigger points causes systemic physiologic effects [abstract].
      • Srbely J
      • Dickey JP
      Randomized controlled study of the antinociceptive effect of ultrasound on trigger point sensitivity: novel applications in myofascial therapy.
      applied therapeutic-intensity vs low-intensity US to trapezius TrPs in 44 subjects. Pressure pain thresholds over trapezius TrPs increased 44% (14.2%) in the first group, whereas no increase was obtained in the second group.

      Evidence Synthesis of Other Conservative Therapies

      Table 9 summarizes the evidence retrieved in this review.
      Table 9Literature review: all studies of other conservative therapies
      Study typeOxford levelNumber
      Systematic reviews1a2
      Systematic review protocols1
      Practice guidelines1a2
      RCTs1b29

      Clinical Practice Recommendations

      • 1.
        Laser: There is substantial evidence that laser therapy is effective in the treatment of TrPs and MPS. The evidence level is A.
      • 2.
        TENS: There is moderately strong evidence that TENS may be effective in providing immediate relief at TrPs. The evidence level is B.
      • 3.
        There is limited evidence for the effectiveness of other forms of electrotherapy: FREMS, HVGS, EMS, and IFC. The evidence level is C.
      • 4.
        US: There is conflicting evidence as to whether US is no more effective than placebo or is somewhat more effective than other therapies in the treatment of TrPs and MPS. The evidence level is C.
      • 5.
        Magnets: There is some evidence that magnets may be effective in the treatment of TrPs and MPS. The evidence level is B.
      • 6.
        Acupuncture: There is some evidence that a course of deep acupuncture to TrPs is effective in the treatment of myofascial pain for up to 3 months. The evidence level is B.

      Conclusion

      The published evidence for the treatment of MPS and TrPs by common chiropractic treatments has been reviewed. Although publications ranging from systematic reviews and clinical trials to clinical reviews were included in the review, the evidence ratings were developed only on the basis of the clinical trial evidence. Manual-type therapies and some physiologic therapeutic modalities have acceptable evidentiary support in the treatment of MPS and TrPs (Table 10).

      Practical Applications

      • There is evidence that manual therapies are useful in short-term relief of TrP pain.
      • There is evidence that laser and acupuncture are useful in the short- and long-term relief of MPS.
      Table 10Summary of recommendations
      TopicConclusion and strength of evidence rating
      Manipulation/mobilizationRating B: short-term relief
      There is moderately strong evidence to support the use of some manual therapies (manipulation, ischemic pressure) in providing immediate relief of pain at MTrPs.
      Rating C: long-term relief
      There is limited evidence to support the use of some manual therapies in providing long-term relief of pain at MTrPs.
      Conservative nonmanipulationRating A: laser therapies
      There is strong evidence that laser therapy (various types of lasers) is effective in the treatment of MTrPs and MPS.
      Rating B: TENS, magnets, and acupuncture
      There is moderately strong evidence that TENS is effective in the short-term relief of pain at MTrPs.
      There is moderately strong evidence that magnet herapy is effective in the relief of pain at MTrP and in MPS.
      There is moderately strong evidence that a course of deep acupuncture to MTrPs is effective in the treatment of MTrPs and MPS for up to 3 mo.
      Rating C: electrotherapies, US
      There is limited evidence for the effectiveness of EMS, HVGS, IFC, and FREMS in the treatment of MTrPs and MPS.
      There is conflicting evidence that US is no more effective than placebo or is somewhat more effective than other therapies in the treatment of MTrPs and MPS.

      Appendix A. Reference list of case studies of conservative treatments of MPS/TrPs

      Anderson RU, Wise D, Sawyer T, Chan C. Integration of myofascial trigger point release and paradoxical relaxation training treatment of chronic pelvic pain in men. J Urol 2005 Jul;174(1):155-60.
      Brewer G, Kampschroeder F, Moore L. Trigger point and transverse frictional massage: a case report. Chiropr 1990;6:40-42.
      Crawford JS, Simpson J, Crawford P. Myofascial release provides symptomatic relief from chest wall tenderness occasionally seen following lumpectomy and radiation in breast cancer patients. Int J Radiat Oncol Biol Phys 1996 Mar 15;34(5):1188-9.
      Daniells E, Wood T. Chiropractic care protocol versus stretching in the treatment of active trigger point in the extensor muscles of the hand and fingers. Toronto, ON: Proceedings of the World Federation of Chiropractic, 7th Biennial Congress 2003:311-312.
      Davies C. Trigger point therapy for carpal tunnel syndrome: self-applied massage of the forearms and scalenes. J Am Chiropr Assoc 2002;39:18-23.
      De Franca G, Levine L. Quadratus lumborum and low back pain. J Manipulative Physiol Therap 1991;14:142-149.
      Grobli C, Dejung B. Non-medical therapy of myofascial pain. Schmerz 2003;17:475-480.
      Han SC, Harrison P. Myofascial pain syndrome and trigger point management. Reg Anaesth 1997;22:89-101.
      Hong C. Specific sequential myofascial trigger point therapy in the treatment of a patient with myofascial pain syndrome associated with reflex sympathetic dystrophy. Australas Chiropr Osteopath 2000;9:7-11.
      Howitt SD, Wong J, Zabukovec S. The conservative treatment of trigger thumb using Graston Technique and Active Release Techniques®. J Can Chiropr Assoc 2006;50:249-254.
      Hsieh H, Hong C. Effect of chiropractic manipulation on the pain threshold of myofascial trigger point: a pilot study. Proceedings of: International Conference on Spinal Manipulation 1990:359-363.
      Hunter G. Specific soft tissue mobilization in the management of soft tissue dysfunction. Man Ther 1998;3:2-11.
      Hyde, T. (2003). Graston technique: a soft tissue treatment for athletic injuries. DC Tracts Fall 2003.
      Kasunich NJ. Changes in low back pain in a long distance runner after stretching the iliotibial band. J Chiropr Med 2003;2:37-40.
      Kaye MJ. Evaluation and treatment of a patient with upper quarter myofascial pain syndrome. J Sports Chiropr Rehabil 2001;15:26-33.
      Leahy P. Improved treatments for carpal tunnel and related syndromes. Chiropr Sports Med 1995;9(1):6-9.
      Leahy, PM. Active release techniques: soft tissue management system for the upper extremity. Colorado Springs, CO: Self-published, 1996.
      Leahy, PM, Mock LE. Myofascial release technique and mechanical compromise of peripheral nerves of the upper extremity. Chiropr Sports Med 1992;6:139-150.
      Melham TJ, Sevier TL et al. Chronic ankle pain and fibrosis successfully treated with a new noninvasive augmented soft tissue mobilization technique (ASTM): a case report. Med Sci in Sports Exer 1998;30(6):801-4.
      Mock LE. (1997) Myofascial release treatment of specific muscles of the upper extremity. Part 1. Clin Bull Myofasc Ther 2(1):5-23.1997
      Mock LE. (1997) Myofascial release treatment of specific muscles of the upper extremity. Part 2. Clin Bull Myofasc Ther 2(2/3):5-22.1997
      Mock LE. (1997) Myofascial release treatment of specific muscles of the upper extremity. Part 3. Clin Bull Myofasc Ther 2(4):51-69.1997
      Mock LE. (1998) Myofascial release treatment of specific muscles of the upper extremity. Part 4. Clin Bull Myofasc Ther 3(1):71-93.
      Mulcahy R, Johnson J, Witt R. Treatment of myofascial pain utilizing an activator instrument on trigger points. Chiropractic 1994;9:45-46.
      Such GW. Manual care of the hyoid complex. Top Clin Chirop 2002;9:54-62. c/r
      Walsh MJ, Wise P. Chiropractic treatment of fibromyalgia: two case studies. Chiropr J Aust 2001;31:42-46.

      References

        • Travell J
        • Rinzler S
        The myofascial genesis of pain.
        Postgrad Med. 1952; 11: 425-434
        • Travell J
        • Simons DG
        Myofascial pain and dysfunction: the trigger point manual.
        Williams and Wilkens, Baltimore (Md)1983
        • Harden RN
        • Bruehl SP
        • Gass S
        • Niemiec C
        • Barbick B
        Signs and symptoms of the myofascial pain syndrome: a national survey of pain management providers.
        Clin J Pain. 2000; 16: 64-72
        • Skootsky SA
        • Jaeger B
        • Oye RK
        Prevalence of myofascial pain in general internal medicine.
        West J Med. 1989; 151: 157-160
        • Nimmo RL
        The development of chiropractic through the perspective of Dr. Raymond Nimmo [videorecording].
        Texas Chiropractic College, Pasadena (Tex)1984
        • Nimmo RL
        The receptor-tonus method.
        Texas Chiropractic College, Pasedena (Tex)1992
      1. Nimmo RL. The receptor-tonus method: directory 1962. Self-published.

        • Cohen JH
        • Gibbons RW
        • Raymond L
        Nimmo and the evolution of trigger point therapy, 1929-1986.
        J Manipulative Physiol Ther. 1998; 21: 167-172
        • Schneider M
        Receptor-tonus technique assessment.
        Chiropr Tech. 1994; 6: 156-159
        • Schneider M
        The collected writings of Nimmo and Vannerson: pioneers of chiropractic trigger point therapy.
        Michael Schneider, Pittsburgh (Pa)2001
        • Schneider MJ
        Snapping hip syndrome in a marathon runner: treatment by manual trigger point therapy—a case study.
        Chiropr Sports Med. 1990; 4: 54-58
        • Schneider M
        Tender points/fibromyalgia vs trigger points/myofascial pain syndrome: a need for clarity in terminology and differential diagnosis.
        J Manipulative Physiol Ther. 1995; 18: 398-406
        • Perle SM
        Understanding trigger points: key to relieving myotogenous pain.
        Chiropr J. 1989; 3: 17
        • Perle SM
        Myofascial trigger points.
        Chiropr Sports Med. 1995; 9: 106-108
        • Hains G
        Locating and treating low back pain of myofascial origin by ischemic compression.
        J Can Chiropr Assoc. 2002; 46: 257-264
        • Hains G
        Chiropractic management of shoulder pain and dysfunction of myofascial origin using ischemic compression techniques.
        J Can Chiropr Assoc. 2002; 46: 192-200
        • Hammer W
        Functional soft tissue examination & treatment by manual methods.
        3rd ed. Jones & Bartlett, Sudbury (Mass)2007
        • Harris RE
        • Clauw DJ
        The use of complementary medical therapies in the management of myofascial pain disorders.
        Curr Pain Headache Rep. 2002; 6: 370-374
        • Phillips B
        • Ball C
        • Sackett D
        • Badenoch D
        • Straus S
        • Haynes B
        • Dawes M
        Levels of evidence.
        Oxford Centre for Evidence-based Medicine, Oxford, UK2001
        • Sackett DL
        • Straus SE
        • Richardson
        • et al.
        Evidence-based medicine: how to practice and teach EBM.
        Churchill Livingstone, Edinburgh, Scotland2000
        • Fernandez de las Penas C
        • Sohrbeck Campo M
        • Fernandez Carnero J
        • Miangolarra Page JC
        Manual therapies in myofascial trigger point treatment: a systematic review.
        J Bodywork Mov Ther. 2005; 9: 27-34
        • Rickards LD
        The effectiveness of non-invasive treatments for active myofascial trigger point pain: a systematic review of the literature.
        Int J Osteopath Med. 2006; 9: 120-136
        • Gam AN
        • Warming S
        • Larsen LH
        Treatment of myofascial trigger points with ultrasound combined with massage and exercise: a randomized controlled trial.
        Pain. 1998; 77: 73-79
        • Jaeger B
        • Reeves JL
        Quantification of changes in myofascial trigger point sensitivity with the pressure algometer following passive stretch.
        Pain. 1986; 27: 203-210
        • Hanten W
        • Olson S
        • Butts N
        • Nowicki A
        Effectiveness of a home program of ischemic pressure followed by sustained stretch for treatment of myofascial trigger points.
        Phys Ther. 2000; 80: 997-1003
        • Hong CZ
        • Chen YC
        • Pon CH
        • Yu J
        Immediate effects of various physical medicine modalities on pain threshold of an active myofascial trigger point.
        J Musculoskelet Pain. 1993; 1: 37-53
        • Hou CR
        • Tsai LC
        • Cheng KF
        • Chung KC
        • Hong CZ
        Immediate effects of various physical therapy modalities on cervical myofascial pain and trigger point sensitivity.
        Arch Phys Med Rehabil. 2002; 83: 1406-1414
        • Hanten WP
        • Barret M
        • Gillespie-Plesko M
        • Jump KA
        • Olson SL
        Effects of active head retraction with retraction/extension and occipital release on the pressure pain threshold of cervical and scapular trigger points.
        Physiother Theory Pract. 1997; 13: 285-291
        • Dardzinski JA
        • Ostrov BE
        • Hamann LS
        Myofascial pain unresponsive to standard treatment. Successful use of strain and counterstrain technique in physical therapy.
        J Clin Rheum. 2000; 6: 169-174
        • Chatchawan U
        • Thinkhamrop B
        • Kharmawan S
        • Knowles J
        • Eungpinichpong W
        Effectiveness of traditional Thai massage versus Swedish massage among patients with back pain associated with myofascial trigger points.
        J Bodywork Mov Ther. 2005; 9: 298-309
        • Fernandez de las Penas C
        • Alonso-Blanco C
        • Fernandez-Carnero J
        • Miangolarra-Page JC
        The immediate effect of ischemic compression technique and transverse friction massage on tenderness of active and latent myofascial trigger points: a pilot study.
        J Bodywork Mov Ther. 2006; 10: 3-9
        • Edwards J
        • Knowles N
        Superficial dry needling and active stretching in the treatment of myofascial pain—a randomised controlled trial.
        Acupunct Med. 2003; 21: 80-86
        • Kilkenny MB
        • Deane K
        • Smith KA
        • Eyre S
        Non-invasive physical treatments of myofascial pain (protocol).
        Cochrane Library. 2007;
        • Terrett AC
        • Vernon H
        Manipulation and pain tolerance. A controlled study of the effect of spinal manipulation on paraspinal cutaneous pain tolerance levels.
        Am J Phys Med. 1984; 63: 217-225
        • Vernon HT
        • Aker P
        • Burns S
        • Viljakaanen S
        • Short L
        Pressure pain threshold evaluation of the effect of spinal manipulation in the treatment of chronic neck pain: a pilot study.
        J Manipulative Physiol Ther. 1990; 13: 13-16
        • Cote P
        • Mior SA
        • Vernon H
        The short-term effect of a spinal manipulation on pain/pressure threshold in patients with chronic mechanical low back pain.
        J Manipulative Physiol Ther. 1994; 17: 364-368
        • Vicenzino B
        • Collins D
        • Wright A
        The initial effects of a cervical spine manipulative physiotherapy treatment on the pain and dysfunction of lateral epicondylalgia.
        Pain. 1996; 68: 69-74
        • Greene C
        • Debias D
        • Helig D
        • Nicholas A
        • England K
        • Ehrenfeuchter W
        • Young W
        The effect of helium-neon laser and osteopathic manipulation on soft-tissue trigger points.
        J Am Osteopath Assoc. 1990; 90: 638-639
        • Atienza Meseguer A
        • Fernandez de las Penas C
        • Navarro-Poza JL
        • Rodriguez-Blanco C
        • Bosca Gandia JJ
        Immediate effects of the strain/counterstrain technique in local pain evoked by tender points in the upper trapezius muscle.
        Clin Chiropr. 2006; 9: 112-118
        • Fryer G
        • Hodgson L
        The effect of manual pressure release on myofascial trigger points in the upper trapezius muscle.
        J Bodywork Mov Ther. 2005; 9: 248-255
        • Hong CZ
        Myofascial pain therapy.
        J Musculoskelet Pain. 2004; 12: 37-43
        • Gerwin RD
        A review of myofascial pain and fibromyalgia—factors that promote their persistence.
        Acupunct Med. 2005; 23: 121-134
        • Alvarez DJ
        • Rockwell PG
        Trigger points: diagnosis and management.
        Am Fam Physician. 2002; 65: 653-660
        • Simons DG
        Understanding effective treatments of myofascial trigger points.
        J Bodywork Mov Ther. 2002; 6: 81-88
        • Harden RN
        Muscle pain syndromes.
        Am J Phys Med Rehabil. 2007; 86: S47-S58
        • Lavelle ED
        • Lavelle W
        • Smith HS
        Myofascial trigger points.
        Med Clin North Am. 2007; 91: 229-239
        • Lewit K
        Post-isometric relaxation in combination with other methods of muscular facilitation and inhibition.
        Man Med. 1986; 2: 101-104
        • Esenyel M
        • Caglar N
        • Aldemir T
        Treatment of myofascial pain.
        Am J Phys Med Rehabil. 2000; 79: 48-52
        • Simunovic Z
        • Trobonjaca T
        • Trobonjaca Z
        Treatment of media land lateral epicondylitis—tennis and golfer's elbow—with low level laser therapy: a multicentre double-blind, placebo-controlled clinical study on 324 patients.
        J Clin Laser Med Surg. 1998; 16: 145-151
        • Cummings TM
        • White AR
        Needling therapies in the management of myofascial trigger point pain: a systematic review.
        Arch Phys Med Rehabil. 2001; 82: 986-992
        • Gur A
        • Sarac AJ
        • Cevik R
        • Altindag O
        • Sarac S
        Efficacy of 904 nm gallium arsenide low level laser therapy in the management of chronic myofascial pain in the neck: a double-blind and randomized controlled trial.
        Lasers Surg Med. 2004; 35: 229-235
        • Snyder-Mackler L
        • Barry AJ
        • Perkins AI
        • Soucek MD
        The effects of helium-neon laser irradiation on skin resistance and pain in patients with trigger points in the neck or back.
        Phys Ther. 1989; 69: 336-341
        • Ceccherelli F
        • Altafini L
        • Lo Castro G
        • Avila A
        • Ambrosio F
        • Giron GP
        Diode laser in cervical myofascial pain: a double-blind study versus placebo.
        Clin J Pain. 1989; 5: 301-304
        • Hakguder A
        • Birtane M
        • Gurcan S
        • Kokino S
        • Turan FN
        Efficacy of low level laser therapy in myofascial pain syndrome: an algometric and thermographic evaluation.
        Lasers Surg Med. 2003; 33: 339-343
        • Ilbuldu E
        • Cakmak A
        • Disci R
        • Aydin R
        Comparison of laser, dry needling and placebo laser treatments in myofascial pain syndrome.
        Rheumatol Int. 2003; 25: 23-27
        • Altan L
        • Bingol U
        • Aydae M
        • Yurtkuran M
        Investigation of the effect of GA AS laser therapy on cervical myofascial pain syndrome.
        Rheumatol Int. 2003; 25: 23-27
        • Graff-Radford SB
        • Reeves JL
        • Jaeger B
        Management of head and neck pain: the effectiveness of altering perpetuating factors in myofascial pain.
        Headache. 1986; 27: 186-190
        • Farina S
        • Casarotto M
        • Bennelle M
        • Tinazzi M
        • Fiaschi A
        • Goldoni M
        • et al.
        A randomised controlled study on the effect of two different treatments (FREMS and TENS) in myofascial pain syndrome.
        Eura Medicophys. 2004; 40: 293-301
        • Hsueh TC
        • Cheng PT
        • Kuan TS
        • Hong CZ
        The immediate effectiveness of electrical nerve stimulation and electrical muscle stimulation on myofascial trigger points.
        Am J Phys Med Rehabil. 1997; 76: 471-476
        • Ardic F
        • Sarhus M
        • Topuz O
        Comparison of two different techniques of electrotherapy on myofascial pain.
        J Back Musculoskelet Rehabil. 2002; 16: 11-16
        • Tanrikut A
        • Ozaras N
        • Ali Kaptan H
        • Guven Z
        • Kayhan O
        High voltage galvanic stimulation in myofascial pain syndrome.
        J Musculoskelet Pain. 2003; 11: 11-15
        • Brown CS
        • Ling FW
        • Wan JY
        • Pilia AA
        Efficacy of static magnetic field therapy in chronic pelvic pain: a double-blind pilot study.
        Am J Obstet Gynecol. 2002; 187: 1581-1587
        • Smania N
        • Corato E
        • Fiaschi A
        • Pietropoli P Aglioti SM
        • Tinazzi M
        Repetitive magnetic stimulation: a novel approach for myofascial pain syndrome.
        J Neurol. 2005; 252: 307-314
        • Smania N
        • Corato E
        • Fiaschi A
        • Pietropoli P Aglioti SM
        • Tinazzi M
        Therapeutic effects of peripheral repetitive magnetic stimulation on myofascial pain syndrome.
        Clin Neurophysiol. 2003; 114: 350-358
        • Maljesi J
        • Unalan H
        High power pain threshold ultrasound technique in the treatment of active myofascial trigger points: a randomized, double-blind case-control study.
        Arch Phys Med Rehabil. 2004; 85: 833-836
        • Lee JC
        • Lin Dt
        • Hong C
        The effectiveness of simultaneous thermotherapy with ultrasound and electrotherapy with combined AC and DC current on the immediate pain relief of myofascial trigger points.
        J Musculoskelet Pain. 1997; 5: 81-90
        • Birch S
        • Jamison RN
        Controlled trial of Japanese acupuncture for chronic myofascial neck pain: assessment of specific and nonspecific effects of treatment.
        Clin J Pain. 1998; 14: 248-255
        • Johannson A
        • Wenneberg B
        • Wagersten C
        • Haraldson T
        Acupuncture in treatment of facial muscular pain.
        Acta Odontol Scand. 1991; 49: 153-158
        • Kisiel C
        • Lindh C
        Smartlindring med fysikalsk terapi och manuell akupnktur vid myofasciella nackoch skuldersmartor.
        Sjukgymnasten. 1996; 12: 24-31
        • Ceccherelli F
        • Tortora P
        • Nassimbeni C
        • Casale R
        • Gagliardi G
        • Giron G
        The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain.
        Complement Ther Med. 2006; 14: 47-52
        • Itoh K
        • Katsumi Y
        • Kitakoji H
        Trigger point acupuncture treatment of chronic low back pain in elderly patients—a blinded RCT.
        Acupunct Med. 2004; 22: 170-177
        • Ceccherelli F
        • Rigoni MT
        • Gagliardi G
        • Ruzzante L
        Comparison of superficial and deep acupuncture in the treatment of lumbar myofascial pain: a double-blind randomized controlled study.
        Clin J Pain. 2002; 18: 149-153
        • Goddard G
        • Karibe H
        • McNeill C
        • Villafuerte E
        Acupuncture and sham acupuncture reduce muscle pain in myofascial pain patients.
        J Orofac Pain. 2002; 16: 71-76
        • Ceccherelli F
        • Bordin M
        • Gagliardi G
        • Caravello M
        Comparison between superficial and deep acupuncture in the treatment of shoulder myofascial pain: a randomized and controlled study.
        Acupunct Electrother Res. 2001; 26: 229-238
        • Olavi A
        • Pekka G
        • Pertti K
        • Pekka P
        Effects of infrared laser therapy at treated and non-treated trigger points.
        Acupunct Electrother Res. 1989; 14: 9-14
        • Srbely J
        • Dickey JP
        Stimulation of myofascial trigger points causes systemic physiologic effects [abstract].
        J Can Chiropr Assoc. 2005; 49: 75
        • Srbely J
        • Dickey JP
        Randomized controlled study of the antinociceptive effect of ultrasound on trigger point sensitivity: novel applications in myofascial therapy.
        Clin Rehabil. 2007; 21: 411-417