From a Clinical Perspective, Myofascial Trigger Points Describe a Phenomenon
An international panel of 60 clinicians and researchers was recently consulted to establish a consensus for identification of a myofascial trigger point (MTrPs). The panel agreed on two palpatory and one symptom criteria: a taut band, a hypersensitive spot, and referred pain (Fernández-de-Las-Peñas & Dommerholt 2018).
These clinical findings may be help clinicians investigate common pain patterns, such as:
• Neck Pain (Morikawa et al. 2017)
• Migraine Headaches (Landgraf et al. 2018)
• Tension-Type Headache (Fernández-De-Las-Peñas & Arendt-Nielsen 2017)
• Carpal Tunnel Syndrome (Meder et al. 2017)
• Low Back Pain (Takamoto et al. 2015)
• Chronic Pelvic Pain (Fuentes-Márquez et al. 2018)
Sore Spots Exist, but Their Etiology is Still Not Well Understood.
It has been demonstrated that patients benefit from hands on work aimed at MTrPs, but this may not always be due to reasons we once were taught. One issue is that ascribing patient’s pain solely to MTrPs or other tissue-driven pain problem is often an oversimplification of a complex process. When it comes to MTrPs there are a number of competing hypothesis, including, but not limited to:
Cinderella Hypothesis - low-level, continuous muscle contractions overload tissues and makes “Cinderella” fibers susceptible to calcium dysregulation and subsequently sarcomere contracture (Bron et al. 2012).
Expanded Integrated Hypothesis - the zone around a MTrP seems to be in an ischemic state resulting in a shortage of glucose and oxygen for metabolism and subsequent sarcomere contracture (Gerwin et al 2004).
Neurogenic Inflammation - the release of inflammatory substances from the nerve axon, result in a lower the threshold for depolarization (Quintner et al. 2015).
Central Sensitization - several studies support the hypothesis that persistent nociceptive input from MTrP contributes to the development of central sensitization and/or changes in the dorsal horn. In contrast, preliminary evidence suggests that central sensitization can also promote MTrP activity (Fernández-de-las-Peñas et al. 2014).
The Treatment of Trigerpoints
A recent randomized, placebo-controlled trial was carried out to investigate changes in nutritive blood flow as well as glucose and lactate following massage. The researchers found there was no effect on nutritive blood flow or glucose, however there was an increase of lactate levels for massage versus sham ultrasound (Moraska et al. 2018).
So while this study found no significant changes in bloodflow, there was increase in anaerobic metabolism following the treatment. It is however important to mention, that like other massage techniques investigation into mechanisms of action should extend beyond local tissue changes and include peripheral and central pain modulation. Meaning that an observed favorable outcome may be explained by a number of overlapping responses in the periphery, spinal cord, and brain (Chimenti et al. 2018).
Stepping Back: What is the Big Picture?
The explanations used in the past of this observable phenomenon seem to be flawed in reasoning, but I do not think there is a need to abandon a multidimensional treatment approaches that provide patients with pain relief. What is needed is an updated explanation of myofascial triggerpoints aligned with the biopsychosocial model pain.
More to Explore
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Chen et al. (2016). Quantification of Myofascial Taut Bands. Archives of Physical Medicine and Rehabilitation. Archives of Physical Medicine and Rehabilitation.
Chimenti et al. (2018). A Mechanism-Based Approach to Physical Therapist Management of Pain. Phys Ther.
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Fernández-De-Las-Peñas, C. & Arendt-Nielsen, L. (2017). Improving understanding of trigger points and widespread pressure pain sensitivity in tension-type headache patients: clinical implications. Expert Rev Neurother.
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Fuentes-Márquez et al. (2018). Trigger Points, Pressure Pain Hyperalgesia, and Mechanosensitivity of Neural Tissue in Women with Chronic Pelvic Pain. Pain Med.
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Moraska, A.F., Hickner, R.C., ... Kohrt, W.M. (2018). Increase in lactate without change in nutritive blood flow or glucose at active trigger points following massage: A randomized clinical trial. Arch Phys Med Rehabil.
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