Trigger Points & Their Magicness: Evidences up to 2021

“Hot topic: trigger points - myth or magic?” This is the title of an article posted in Frontline, a magazine for members of the British Chartered Society of Physiotherapy (Frontline, 2015).

The trigger point (TrP) or myofascial trigger point (MtrP) is considered by many musculoskeletal professionals to be the underlying cause of myofascial pain syndromes. It was described by Travell and Rinzler in 1946 (Travell et alk 1946), and has been increasingly studied since, with a constant controversy over its existence (Quintner, JL, 2015).

Opinions Conflicting Each Other Head-to-Head

The article, which seems to be an editorial of the magazine because it was authored by Frontline, presented two opinions which are conflicting each other head to head. The article goes as below.

Magic: Simeon Niel Asher

Simeon Niel Asher is an osteopath and leading expert on trigger points who uses the therapy in his work.

• Therapeutic touch has emerged in all cultures in all ages.?
• Massaging painful muscular spots occurred in ancient Egypt, India, Japan, Korea, Rome, Greece and Mesopotamia. In the west, Gowers (describing it as ‘fibrositis’) and later Kellegren, Gunn, Travell and Simons rationalised these hyperirritable spots as ‘trigger points’. Dunbar suggests that touch triggers neurobiological mechanisms via slow unmyelinated CT afferent fibres and a neuroendocrine cascade (oxytocin and endorphins).?
• According to Gerwin up to 95 per cent of mechanical musculoskeletal pain may be trigger point related.?
• Mense has produced an elegant body of work elucidating the mechanism of peripheral muscle pain resulting in peripheral sensitisation, and central sensitisation from his research in animal models, summarised in his text Muscle Pain.?
• Studies over the past decade have imaged trigger points, shown that their activation results in central nervous system activation through fMRI scanning, demonstrated electrophysiological activity at the trigger point, and have shown biochemical changes in the trigger point zone.
• Further studies have shown that manipulation of the trigger point modulates muscle function and induces local and referred pain. ?
• Quinter and Cohen do not deny the existence of trigger points but question the pathophysiological basis and suggest a neuritis model.?
• This model, while interesting, does not fit the clinical experience.?
• For over 20 years the Quinter and Cohen argument has been simmering away, where it has been proposed and rebuffed. While we may not have the complete mechanisms (new theories abound) for trigger points, their efficacy, relevance and increasing evidence base is compelling.

Myth: Adam Meakins

Adam Meakins is a leading sports physio at Spire Bushey Hospital, Hertfordshire. ?He is unconvinced on trigger points.

• Trigger points are believed to be localised areas of adverse muscular contraction that can be palpated as abnormal knots or taut bands. These are thought to be created by a biochemical crisis at the motor end plate due to direct or indirect trauma to muscle fibres from sustained postures or repeated muscular stresses or strains.?
• However, despite common belief, there is no robust evidence to support this theory and questions have been raised as to its validity.?
• Research consistently shows poor reliability in the ability of therapists to locate adverse muscle knots or taut bands with even the world’s leading experts, including David Simons, being unable to locate them. If trigger points really are muscle knots or taut bands, why can’t we locate them?
• Studies have also attempted to prove the existence of trigger points as adverse muscle knots with imaging and biochemical analysis. These all have poor methodology with high risk of bias. The results were never repeated independently.
• Trigger points are often treated with soft tissue therapy involving deep sustained pressure or invasive techniques such as dry needling in a belief that it disrupts this motor end plate crisis. However, despite claims of effectiveness, the mechanisms of effect for these treatments are unknown and can be attributed to other neurological and psychological pain-relieving mechanisms such as diffuse noxious inhibitory controls or placebo effects.
• I believe that what therapists perceive as adverse muscle knots or taut bands are in fact a palpation illusion of normal anatomy and structure, which unfortunately is driven by an institutional dogma and peer pressure to find them.
• I argue that trigger points are sore spots of an unknown origin for most, or potentially due to subcutaneous peripheral neural inflammation or ischemia, and do not require needles or thumbs painfully pressed into them to elevate them.

What Can Be Called Magic?

In medicine, a magic item can be defined as something that can, by it alone, cause a remarkable therapeutic effect with very high certainty.

TrP theory is widely used to guide the usage of dry needling (DN) in pain management. So dry-needling is also called TrP dry needling (TrP DN). If TrP DN can magically treat pain syndromes, then TrP would be very possibly a magic theory.

TrP Dry Needling Tested by 2,715 Trials

With the above definition in mind, I did a google search of systematic literature reviews on the efficacy of TrP DN for pain treatment. But I did not find any reviews which concluded that TrP DN is remarkably effective with high certainty.

Numerous studies have been conducted in the last half century on the therapeutic efficacy of TrP DN, but the absolute majority of them were inconclusive.

A 2021 systematic review (Mohammadreza P et al, 2021) identified 2,715 TrP DN studies for headache and concluded:

• Dry needling seems, with very low-quality evidence, to produce effect no better than other interventions for short-term pain relief.
• Dry needling seems to be better than other therapies for improving disability in the short term.
• Further high quality studies are warranted to provide a more robust conclusion.

The review was jointly authored by 9 researchers, who have PT or MD or PhD titles, from Iran, USA, Spain, the Netherlands, and Pakistan (Mohammadreza P et al, 2021). A worldwide team researchers.

A 2020 systematic review including 28 trials on the efficacy of DN for neck pain (Marcos J.N.S. et al, 2020) concluded:

• Low to moderate evidence suggests that dry needling can be effective for improving pain intensity and pain-related disability in individuals with neck pain symptoms associated with TrPs at the short-term.
• No significant effects on pressure pain sensitivity or cervical range of motion were observed.

In summary, the evidence-based data so far demonstrated that TrP DN is filled with uncertainty. After you put a needle in, you are never sure what will happen to the patients. Performing TrP DN is just a shot in the dark then pray.

Even it works, the effect size is very small. Clinically significant effect can not be obtained until after a few weeks even months of treatment combined with a variety of labor intensive manual interventions which imposed too much burden onto both patients and clinicians.

A 2017 systematic review investigated the efficacy of TrP DN performed by physical therapists (Gatti E et al, 2017). The conclusion:

• Very low-quality to moderate-quality evidence suggests that dry needling performed by physical therapists is more effective than no treatment, sham dry needling, and other treatments for reducing pain..,

• Low-quality evidence suggests superior outcomes with dry needling for functional outcomes when compared to no treatment or sham needling.
• No difference in functional outcomes exists when compared to other physical therapy treatments.
• Evidence of long-term benefit of dry needling is currently lacking.

TrP DN: An Adjunct Gadget

TrP DN is almost always used as part of a larger pain management plan that could include exercise, stretching, massage and other techniques (Cleveland Clinic). According to Mayo Clinic, “Dry needling is a safe, minimally painful and often very effective technique for people with certain musculoskeletal conditions. Many people have found the treatment to be a game-changer in improving their quality of life”.

Is TrP DN A Magic?

As talked earlier, a magic item in medicine can be defined as something that can, by it alone, cause a remarkable therapeutic effect with very high certainty.

Unfortunately, TrP DN does not meet even a portion of this definition. This raised a question over the "magicness" of TrP.

On the other hand, it is possible that, while many professionals including the world’s leading experts are unable to locate TrPs, some musculoskeletal therapists may have a very special skill in identifying TrPs thus they could turn TrP DN in to a magic therapy. However, such magic cases seem rarely happen at least in the community of researchers worldwide who have conducted thousands of trials on TrP in the last few decades.

If a magic theory could not be easily, reliably and consistently verified by many clinicians nor by scientist's randomly controlled trials, will that "magicness" still make sense?

TrP DN vs Meridian Acupuncture

In many ways, what TrP theory to DN myofascial therapy can be considered to be what meridian theory to acupuncture therapy. Both theories are charmingly conjectured or hypothesized on a basis that is impalpable, elusive and slippery. No wonder that there are always faithful believers and skeptic deniers.

Trigger points - myth or magic? Amid controversies and debates, science advances. The same is true with TrPs and meridians. With each eventually solved controversy, we will be one step closer to the truth.

References

Frontline, Hot topic: trigger points - myth or magic? Frontline Issue 7, 15 April, 2015 https://www.csp.org.uk/frontline

Gattie E et al, The Effectiveness of Trigger Point Dry Needling for Musculoskeletal Conditions by Physical Therapists: A Systematic Review and Meta-analysis. J Orthop Sports Phys Ther 2017;47(3):133–149

Gattie E et al, Dry Needling Adds No Benefit to the Treatment of Neck Pain: a Sham-Controlled Randomized Clinical Trial With 1-Year Follow-up. Journal of orthopaedic and sports physical therapy, 2021, 51(1), 37‐45

Marcos Jose Navarro Santana et al, Effectiveness of Dry Needling for Myofascial Trigger Points Associated with Neck Pain Symptoms: An Updated Systematic Review and Meta-Analysis, November 2020, Journal of Clinical Medicine 9(10):3300

Manuel Rodríguez-Huguet et al, Dry Needling in Physical Therapy Treatment of Chronic Neck Pain: Systematic Review. J. Clin. Med. 2022, 11, 2370

Quintner, J.L.; Bove, G.M.; Cohen, M.L. A critical evaluation of the trigger point phenomenon. Rheumatology 2015, 54, 392–399.

Stainton, Lilo H, Physical Therapists Win Latest Battle in Turf War... New Jersy Spotlight News 2018.

Travel, J.; Rinzler, S. Relief of cardiac pain by local block of somatic trigger areas. Proc. Soc. Exp. Biol. Med. 1946, LXIII, 480–482.

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