09. Trigger points and Controversial Treatments.

Table of Content: 01. Remember 02. MTrP? A summary 03. History of MTrP 04. Facts 05. The Dry needle 06. Further Wonderment 07. Conclusion

This blog post concerns a widely debated topic, Myofascial Trigger Points(MTrP), and some evidence-based insights on the relevance, diagnosis, and validity of the diagnosis of MTrP.

Keep in mind that thoughts and insights into the topic are; as muddled as the vagueness of the body of research explaining this phenomenon. So keep a curious and questioning mind while reading.

Let’s Get into it,

What are MTrP?

By definition, Myofascial Trigger points are discrete, focal, and hyperirritable spots located in a taut band of skeletal muscle, with local and referred pain.

These spots are often seen with various musculoskeletal disorders, and a variety of medical conditions including those of metabolic, visceral, endocrine, infectious, and psychological origin.

Conventionally it’s paired with the postural stresses and attributed to repetitive microtrauma, which leads to a sensitive and painful band of muscle (taut band).

Palpation of these taut bands leads to pain directly in the area or radiates to the areas nearby (a zone of reference) and applying a snapping perpendicular pressure elicits a ‘Local twitch response’ (a transient visible or palpable contraction or dimpling of the muscle and skin).

Clinical presentation of MTrP includes a patient presenting with muscular weakness, and reproduction and/or exacerbation of the patient’s spontaneous pain complaint by firm palpation of the spontaneously painful nodule (active MTrP) which is considered the sine qua non of the syndrome.

Additionally, a Latent MTrP (painful only on palpation) spot can also be considered pathognomonic/diagnostic albeit to a lesser extent.

Now, With our definitions straightened,

Let’s talk a little history before getting straight to the facts,

Historically many scientists have pondered on the idea of ‘thickened’ nodules or spots in the fascia or muscles and these ideas have shed light on the disorders of the myofascial organ system (or the ‘orphan system’; generally abstracted from scientific focus).

Though vague associations have been seen as early 1816, the earliest definitive records of such(MTrP) mentions are seen in the works of Ralph Stockman who stated that,

Suggesting that the essential lesion is ‘chronic inflammatory hyperplasia of white fibrous tissue in patches’

Research; pre-Janet Travell’s work showed similar trends,

1. Froriep’s ‘muskelshwiele‘ (muscle callouses),

2. Gower’s fibrositis (inflammation of fibrous tissues) or

3. Schade’s myogeloses (high viscosity muscle colloids).

It was only Kraus’ speculations of Pain-reflex-Pain (vicious cycle hypothesis) and Kellgren’s charting of ‘zones of referred pain’ in tissues, that inspired the works of Janet Travell.

Travell along with Seymour Rinzler continued and formally directed the trend by coining the term ‘myofascial trigger point’ and claimed that

So, It sounds fine to me, what’s the fuss about? To explain, let’s continue the discussion,

Wondering about the facts listed in the summary.

1. Uncertainty:

As stated above, the presence and association of MTrP with a wide variety of musculoskeletal, metabolic, visceral, endocrine, infectious, and psychological conditions, leads to an unanswered question,

‘Whether the nodule (active or latent MTrP) is an associated finding, whether it is a causal or pathogenic element to pain syndrome and whether or not its disappearance is essential for effective treatment?’

2. Inflammation:

Shah et al’s work on the biochemical milieu of MTrP and surrounding areas, Shows elevated levels of calcitonin, substance P, Norepinephrine, TNF-alpha, IL-1, IL-6 consistent with inflammation, and lower pH (yep! more acidic environment in the active MTrP zone).

However, in subjects with active MTrPs elevated levels of these mediators were found in uninvolved control muscle (gastrocnemius) as well, suggesting that the inflammatory pathology could be present due either to tissue damage or altered peripheral nerve function, not necessarily due to pathology being in the tissue sample. (here)

3. Posture-Posture everywhere:

MTrP are often associated with overuse, and muscle overload, especially of the postural muscles (adding salt to an already abused and stigmatized state of posture).

One of the major explanations of this phenomenon lies in the Cinderella Hypothesis (Kadefors et al.), which reasons that since small motor units are first to be recruited and last to be relaxed during prolonged muscle contractions, these underprivileged units(hence named; ‘cinderella units’) are expected to be contracted for long periods of time; rendering them susceptible to an energy crisis (simultaneous increase in energy consumption, due to impaired relaxation and a decreased energy replenishment due to impaired blood flow in the microvasculature of contracted fibers).

The only counter to this is seen in the work of De Luca and colleagues in the early 2000s, which shows that although phasic muscles; are adapted to intermittent and fast contractions followed by periods of relaxation, motor units are indeed recruited in a hierarchical pattern(the ‘onion skin’ pattern).

However, in postural muscles; during slow and adjusting contractions(as their function) motor units are recruited by rotation rather than by size allowing sequential shift-like relaxation phases, thus suggesting that relaxation time is an important factor to be considered.

Thus, a weak muscle under load(overload) probably is more susceptible, not postural muscles in general. (here)

4. Physical Examination:

Currently, the physical examination as described in ‘The Trigger Point Manual’:

1) Palpation of a taut band;

2) Identification of an exquisitely tender nodule (MTrP) in the taut band, and

3) Reproduction of the patient’s symptomatic pain with sustained pressure. are considered the diagnostic gold standard of this syndrome.

However, there are a few chinks in this armor, I.e, Accurate diagnosis using manual examination ‘depends upon the examiner’s clinical acumen, experience, index of suspicion, training, and palpation skills[sic]’; which paired with general ‘limitations’ of digital palpation (yeah! it lacks adequate sensitivity and specificity) makes it an ‘unconvincing standard’ at best.

Not to forget, when blinded to the diagnosis; there is generally poor reliability of manual palpation in the identification of an MTrP. (here, here, here, here)

which leads to the question, Whether physical examination can be relied upon to diagnose a condition that is supposed to be defined by that physical examination?

5. A new explanation:

Recent studies have indicated that the peripheral nervous system upon detecting danger communicates with the immune system to create a protective neurogenic inflammation. (here)

A cogent statement and plausibly the reason behind ‘biochemical’ findings in MTrP zones.

Onwards to the elephant in the room (ba dum tss!),

Spoiler alert! It’s needles, specifically the dry ones. And the Treatments of MTrPs

Even though there is a myriad of ways proposed to treat MPS(myofascial pain syndrome) such as Non-invasive interventions including compression of the TrP, spray and stretch, transcutaneous electrical stimulation, and, more recently, high-intensity focused US and Invasive treatments including injection of local anesthetic agents, injection of CSs, injection of botulinum toxin, needle acupuncture and dry needling.

Problems(dogma and nocebo) regarding MTrPs arise from a few of their treatments. Thus, for the sake of this blog and argument, we’ll further consider the problematic (invasive) modalities only.

1. In their systematic review, Cummings and White were unable to find evidence that needling therapies have any specific effect.

2. Rickards found limited strength of evidence for any treatment of TrPs.

3. A systematic review of botulinum toxin A for TrP treatment reported that the data were limited and that the patient populations were heterogeneous. (here, here)

A growing body of research remark upon the heterogeneity of the populations being treated, the lack of widely accepted standard diagnostic criteria for MPS and small sample sizes, uncertainty as to whether TrPs were the sole cause of pain, as well as neglect of technical issues such as the variability in the location of TrPs and the depth of needle Insertion in research.

Dragging into yet another question, the “effectiveness” of these invasive treatments. Given their commercial success and popularity among clinicians.

All of this leads to further wonderment:

Why do these clinicians swear by the ‘effectiveness’ of their ‘treatments’?

Why are there such a huge number of anecdotal responses to these treatments?

And

Why is it so difficult to change the perception of those illusioned by the sweet shiny needles?

To answer the first question Let’s revisit the ‘Post hoc ergo propter hoc’ fallacy, this is a logical fallacy that simply translates to ‘after this therefore because of this, a simple example of which could be;

“I danced outside and it started raining, which means my dancing makes it rain.”

This could explain; how the effects of needling(a generally ineffective treatment) could be attributed to the act of ‘needling’ and not the contextual factors around it. This is common when medical treatments are based solely on experience and beliefs rather than pathogenesis and sound reasoning.

To answer the second question, Let’s consider the contextual factors.

Procedures like dry needling are generally accompanied by stretching, manual therapy, home exercises, and other active treatments, and are rarely performed in an isolated fashion. Thus, ignoring the effects of these interventions over the ‘magic’ of needling is quite ignorant and oafish.

Additionally, let’s consider the following hypothetical:

“Alex was ‘diagnosed’ with MPS and ‘treated’ with needling, manual therapy, and home exercise, he was instructed that he might need follow-up sessions of needling for it to take its full effect. Alex the unsuspecting ‘client’, went for 5 sessions, in the meanwhile disregarding home exercises and activity entirely. And after 5 sessions concluded to himself albeit confusingly; that every time he sees the ‘clinician’ his pain reduces and it returns as soon the effects wear off. So, ‘needling’ as his doctor says has become an integral part of him being pain-free and he must continue to go the visits as it has proven to be the only effective thing he tried.”

This can be attributed to the ‘Illusion of Validity’ (we see a relationship between two things even if we are not sure why the occurrences are tied together)

As patient expectations dictate a significant magnitude of treatment outcomes, paired with an expectancy-based Illusion of validity can effectively coax some poor souls into giving their money to some ‘clinician’, even for an uncomfortable, invasive, and generally ineffective ‘treatment’.

One might argue that one possible mechanism of effect could be counterirritation or application of a competing noxious stimulus, so they do work. And the simplest counter to this; is the fact that a common factor shared by most (invasive)therapies is that they elicit pain at the site of their application and given their ineffectiveness and lack of accuracy, these are probably unnecessary (especially when even the diagnosis stands on shaky grounds).

Not to forget the false information, narratives, and nocebo looming over and around the entire concept of MTrP.

Now,

Onto the final question, Why is it so difficult to reason with these clinicians?

The realm of reason from which most ‘needlers’ borrow their thoughts, arguments, and beliefs is riddled with biases,

For example,

1. Reactive Devaluations (unwillingness or inability to hear out and objectively consider the proposal of others)
   

2. Cognitive dissonance (avoiding conflicting beliefs because it makes one feel uncertain or uncomfortable, usually by rejecting or avoiding new information)

3. Law of the Instrument and Commitment bias (using one skill for every opportunity and adhering to past beliefs especially those close to public identity) Summarised beautifully:

1. The illusion of explanatory depth (making decisions based on limited but convincing information)

2. Begging the Question (circular reasoning, when an argument’s premises assume the truth of the conclusion, instead of supporting it.)

To quote Spanish neuroscientist Santiago Ramón y Cajal

Conclusion,

As clinicians, it’s our duty to challenge and reshape what we work with and work for.

Without trying to actively uplift yourself, objectively questioning and discussing what you believe in; with others having opposing views, and changing your behavior and beliefs based on what comes out of the discussions and debates,

All are doomed to failure.

For more go to Physio Explored Blogs

Cover Photo by Katherine Hanlon on Unsplash

Disclaimer: In the presence of pain all the structures and context must be clinically assessed, this blog is in no way a substitute for a clinical assessment and all must consult a physiotherapist or a physician in such conditions.