MORE TROUBLE IN THE LAND OF THE TRIGGER POINT

Introduction

Some clinicians have suggested that myofascial trigger points (MTrPs) might be responsible for the widespread pain that characterises fibromyalgia [2,4], thus conflating two controversial constructs, one of which has been refuted [5,6].

Because the nature of the trigger point (TrP) has been a controversial issue for many years, notwithstanding its refutation, any attempt to formulate a generally accepted definition would attract interest.

The Delphi study

A Delphi study is one method of arriving at a consensus in a systematic interactive way. The process aims to determine the extent to which experts agree about a given issue and in areas where they disagree, to achieve a consensus opinion.

Fernández-de-las-Peñas and Dommerholt [3] conducted a Delphi study amongst 60 international MPS/TrP experts who were selected on the basis of what they considered was “established knowledge,” their “familiarity with MPS and TrPs” and “their ability to influence policy related to MPS (myofascial pain syndrome).”

The authors presumed that the participants were equivalent in knowledge and experience [1]. But this important assumption was never tested.

The questions put to the Delphi panel were formulated following a comprehensive review of the MPS/TrP literature, but obviously excluding that which refuted the construct. They were introduced over three rounds.

The first round

Participants were asked to rate the relative importance (as either “essential” or “confirmatory”) of four symptoms and four palpatory findings considered to be indicative of the “trigger point” phenomenon. Responses by 70% or more participants to each question were then made available and evaluated by the panel.

The second round had three elements

From the list generated in the first round, participants were invited to select three answers that might enable them to identify “active” and “latent” TrPs.

  • They were also asked whether they believe a relationship existed between “active” TrPs and clinical pain (one would have thought that this would be axiomatic).
  • Members were invited to briefly summarize their beliefs on the differences between “active” and “latent” TrPs.
  • Lastly, they addressed the question as to whether they believed TrPs were located in particular anatomical regions, as had been originally proclaimed by Travell and Simons in their Trigger Point Manual [7].

The third round

The sole topic for discussion in the final round was whether referred pain can be considered an essential criterion for the diagnosis of “active” or “latent “TrPs.

Outcomes

Consensus was reached on a cluster of three criteria necessary for identification of a TrP: (i) a taut band in a muscle; (ii) a hypersensitive spot, and (iii) referred pain.

TrP diagnosis required that at least 2 of 3 of these criteria were present. Remarkably, a finding of local tenderness was not considered necessary for the diagnosis of a TrP.

A taut band in muscle was required for the diagnosis of both the “latent” and “active” TrP. Whereas the “latent” TrP exhibited a hypersensitive spot, there was no agreement that this was a necessary requirement for an “active” TrP. However, it was also remarkable that the majority of the experts agreed that palpating “the spot” reproduced the patient’s symptoms.

Pain was considered by most experts to be “referred” whenever it spread to a distant area or was described as a dull ache.

There was no agreement that the anatomical locations of TrPs coincided with the specific locations mapped (and marked with an X) as set out in the Trigger Point Manual [7]. Furthermore, the majority of experts did not support the idea of a distinct referred pain pattern from TrPs present in any given muscle.

Discussion 

Clearly, their lack of agreement on the important questions suggests either that the members of the Delphi panel did not all possess the same level of knowledge and experience, or that the questions put to them highlighted a state of conceptual confusion amongst those who were “inside the tent”.

In the Introduction to their paper, Fernández-de-las-Peñas and Dommerholt [3] confidently asserted that MPS is characterized by the presence of MTrPs.

However, in the light of the Delphi study, they conceded that “The conceptual association between MPS and TrPs has been questioned” and “We do not currently know if MPS is due only to TrPs, or if MPS is an independent pain condition.”

Given that the detection of TrPs had to date been a sine qua non for MPS, should an examiner not be able to detect their presence, how can that examiner be expected to make a diagnosis of MPS? The authors have (again) demonstrated that their construct is a mirage.

Conclusion

This study can only be seen as a desperate attempt by its devotees to stave off the inevitable conclusion that the MPS/TrP conjectures made so long ago by the late Drs Travell and Simons [7] can now once and for all be consigned to the dustbin of medical history.

References

  1. Altschuld JW, Thomas PM Considerations in the application of a modified scree test for Delphi survey data. Evaluation Review 1991; 15 (2): 179-188.
  1. Fernández-de-Las-Peñas C, Arendt-Nielsen L. Myofascial pain and fibromyalgia: two different but overlapping disorders.Pain Manag 2016; 6(4): 401-408. doi: 10.2217/pmt-2016-0013
  1. Fernández-de-las-Peñas C, and Dommerholt J. International Consensus on Diagnostic Criteria and Clinical Considerations of Myofascial Trigger Points: A Delphi Study. Pain Medicine 2017 (in press). doi: 10.1093/pm/pnx207
  1. Liptan GL. Fascia: a missing link in our understanding of the pathology of fibromyalgia. J Bodywork Mov Ther 2010; 14: 3-12.
  1. Quintner JL, Cohen ML. Referred pain of peripheral neural origin: an alternative to the “Myofascial Pain” construct. Clin J Pain 1994; 10: 243-251.
  1. Quintner JL, Bove GM, and Cohen ML. A critical evaluation of the trigger point phenomenon. Rheumatology (Oxford) 2015; 54: 392-399.
  1. Travell JG, Simons DG. Myofascial Pain and Dysfunction: the Trigger Point Manual. Williams and Wilkins: Baltimore, 1983.

 

One Comment

  1. When the above-mentioned article by Fernández-de-las-Peñas and Dommerholt is eventually published in Pain Medicine, it will be accompanied by an Editorial written by Dr Robert Gerwin [2017], one of our main adversaries in the recent heated debate over “trigger points” (TrPs) [Dommerholt & Gerwin 2015].

    Dr Gerwin has picked up on the logical flaw contained in the article:

    “To say that MPS always requires a TrP in order to make the diagnosis is a tautology in the absence of credible evidence because then no diagnosis of MPS could be made in the absence of a TrP.”

    He also raises the question as to whether there is an identifiable condition associated with the so-called “taut band”:

    “Moreover, such an assertion does not address the question of whether or not there is an underlying condition that causes the muscle hardness known as the taut band, its accompanying features, and the pain syndrome known as myofascial pain.”

    In defense of the authors’ purpose in conducting the Delphi study, Dr Gerwin notes that they have been “careful to state that the consensus agreement addresses only the TrP and not the diagnosis of myofascial pain.”

    But perhaps in deference to his previous role as co-owner and director of Myopain Seminars (he stepped down from this role in 2013), Dr Gerwin takes this opportunity to reaffirm his own views on trigger points:

    “I have argued elsewhere that the TrP taut band is a dynamic dysfunctional element in muscle and that it exists in the inactive, nonpainful (sic) state, in a state in which it is tender when firmly palpated but does not cause spontaneous pain (a state that is termed “latent”), and in a state where it both is tender to palpation and causes spontaneous pain (a state that is termed “active”).”

    In conclusion, Dr Gerwin reminds the authors that the criteria have been arrived at by consensus and are NOT evidence-based. He sees their next task as determining whether based on the outcome of clinical studies the criteria for identification of a TrP are clinically valid.

    There will be much work in front of them should they take up the challenge to perform this onerous (well-nigh impossible?) task.

    References:

    Dommerholt J, Gerwin RD. A critical evaluation of Quintner et al: missing the point. J Bodyw Mov Th 2015; 19(2): 193-204. doi: 10.1016/j.jbmt.2015.01.009

    Gerwin R. Trigger point diagnosis: at last, the first word on consensus. Pain Med 2017 (in press). doi: 10.1093/pm/pnx219

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