Key word: myofascial trigger points
The back mice nodules could have been also named “myofascial trigger points or MTrPs” by some authors.
Shah et al. in this article tried to do a complete review about the study of what they called myofascial pain and myofascial trigger points and they admitted that the SUBJECT IS STILL A CONUNDRUM or enigma. The lack of consistent nomenclature, diagnostic criteria, objective assessments and conclusive biopsy findings has LED TO MUCH CONTROVERSY and GENERALLY POOR ACCEPTANCE by mainstream medicine.
(Personal note: It is possible that what they called MTrPS could be back mice… in certain cases. They define them as discreet nodules within a taut band of skeletal muscle that may be spontaneously painful or just painful only upon palpation, that it is exactly how the back mice or the fibrositic nodules could be described, the only difference is that the MTRPS are located at the muscle level, but it COULD BE that what they think is the muscle is the deep subcutaneous layer or the fibro-fatty layer of the septae that divides the muscles.)
Other coincidences are that the “latent MTrPs” could be the asymptomatic back mice, since back mice can be palpated and are not always painful.
The truth is that many surgeons have done biopsies (LINK to articles) of the nodule and have observed that the nodules are located in the DEEP SUBCUTANEOUS LAYER, also the late articles have performed sonographies (LINK to articles) and they have seen that they correspond to the interfascial layers.
Shah et al. DO NOT DISCUSS IN THEIR REVIEW the possibility that the pain could arise from the fibro-fatty tissue, it is like it happens in the mainstream medicine. He mentions that some authors pay attention to the fascial layers, not just the muscle fibers, but the truth is that the fatty tissue itself and the fascial layers are rather IGNORED on the discussion and the focus is placed in the muscle fibers.
Maybe as a consequence of the local pain/tissue tension from the back mice and the cluneal neuropathy there seems to be a kind of MUSCLE SPASM associated. For example, in the case of the lumbar back mice, there would be a reactive erector spinae muscle spasm that would explain the LUMBAGO ATTACK. Once the cluneal nerve branches are blocked with local anesthetic, the patient may recover the mobility. Then, the muscle spasm is a consequence and it will be in the whole length of the muscle fibers, not in patches.
Simons and Travell, two doctors known for the theory of the myofascial syndrome, also used local anesthetic treatment to resolve the MTrPs. The truth is that the fascial layers are also punched while you think that you are puncturing the muscle. So the good results could also be due to the fact of puncturing “real mice” so they are in a less deeper layer than the muscle.
Notes on the article:
Myofascial trigger points then and now: a historical and scientific perspective
Jay P. Shah et al.
Shah et al. start their article with the following statement:
“Myofascial pain is a clinical problem that has generated interest and CONFUSION for decades”.
One of the names that the muscle and fascia pain received was FIBROSITIS. Shah then states that the term fibrositis had been replaced by the term “myofascial pain”.
The diagnosis of “myofascial pain” is related with the presence of “MTrPs or myofascial trigger points” which are discreet, hyperirritable nodules in a taut band of skeletal muscle, which is palpable and tender during physical examination.
An ACTIVE MTrP is clinically associated with spontaneous pain in the immediate surrounding tissue and/or distant sites in specific referred pain patterns. Pressure on the active MTrP exacerbates the patient’s spontaneous pain complaint and mimics the patient’s familiar pain experience. The LATENT MTrP can elicit local pain at the site of the nodule on palpation but not spontaneous pain.
The active and latent MTrPs can be associated with muscle dysfunction, muscle weakness and a limited range of motion.
Historical perspective of the myofascial trigger points
Guillaume de Baillous (1538-1616) from France was one of the first to write about muscle pain disorders in detail.
In 1816, Belfour associated the “thickenings” and the “nodular tumors” in muscle with local and regional pain.
In 1843, Foriep coined the term “muskelshwiele” (muscle callouses) to describe what he believed was a “callus” of the connective tissue.
In 1904, Gowers suggested that the inflammation of the fibrous tissue, fibrositis, created the hard nodules. The biopsy data later discredited that term “fibrositis”, since they could not find any inflammatory process in the fibrous tissue. (Personal note: This statement form Shah et al. is wrong in my opinion. In Gowers’ article called “Lumbago” that he published in 1904 he did not mention the nodules. He was a neurologist and focused on explaining the possible fisiopathological effects of the inflammation of the connective tissue of the MUSCLE SPINDLES to explain the LUMBAGO ATTACK that he himself had suffered).
In 1919, Schade proposed another term for the nodules, and called “myogeloses” the high viscosity muscle colloides.
Michael Gutstein in Germany.
Michael Kelly in Australia.
J.H. Kellgren in Britain, by injecting hypertonic saline into various anatomical structures was able to chart zones of referred pain in neighboring and distant tissue.
Janet Travell and Rinzler in America coined the term “myofascial trigger point” in the 1950s, the term pointed out that the nodules can refer pain to both the muscle and the overlaying fascia.
They published a two-volume book and many articles.
The book: Myofascial pain and dysfunction: the trigger point manual (Janet Travell and David Simons)
Simons states “ Muscle was the orphan organ. No medical specialty claims it”. Simons developed his theories by primarily working with a rabbit model and related the MTrPs with the overuse or overload of the muscle.
The Cinderella hypothesis (Hägg, 1991) relates the formation of the MTrPs with what they call muscle Cinderella fibers.
Other theories related the formation of MTrPs to the consequences of certain ischemia.
The myofascial pain syndrome (MPS)
Shah et al. state that the myofascial pain is different from fibromyalgia, tendinitis or bursitis.
The MPS presents as REGIONAL PAIN SYNDROME, sometimes with referred pain, often accompanied by increased tension and decreased flexibility.
Nevertheless, it has been said that the MPS can coincide with other rheumatic diseases like fibromyalgia, radiculopathies, joint dysfunction, disk pathology, tendonitis, craniomandibular dysfunction, migraines, complex regional syndrome, post-herpetic neuralgia, etc.
One characteristic feature of the MPS would be (not always) the presence of the MTrPs.
Shah et al. mention that, unlike fibromyalgia, the MPS is not widely distributed, but more regional. And it does not present usually sleep or mood disturbances.
THE CONTEMPORARY CONUNDRUM ABOUT THE MTrPs AND MYOFASCIAL PAIN SYNDROME
Shah et al. warn that despite the MTrPs are a common physical finding, it is often OVERLOOKED because its PATOPHYSIOLOGY is not fully understood.
They seem just to be possible to PALPATE, there are no biomarkers, electrodiagnostic test or imaging, and then the DIAGNOSTIC CRITERIA is imprecise.
Furthermore, the MTrPS seem to be associated with a variety of medical conditions such as those that are metabolic, visceral, endocrine, infectious, and of psychological origin. And they are present with other musculoskeletal pain syndromes.
Despite the effort of many researchers, the theories behind the MTrPS are still SPECULATIVE.
The nature of the pain, the intensity and the distribution and duration seem to be HIGHLY DEPENDENT upon the individual’s perception. That makes the diagnostic criteria difficult.
There is controversy: Is the presence of the MTrPs necessary to diagnose the myofascial pain syndrome?
The MtrPs can be found in asymptomatic individuals. These “latent MtrPs” are nodules with the same physical characteristics as the ACTIVE MTrPs. The only difference is that the latent ones do not present spontaneous pain, just upon palpation. But, at the end, the diagnostic criterion for the myofascial pain syndrome is the PRESENCE OF ACTIVE myofascial trigger points.
According to Shah et al., in 2015 it still remained UNKNOWN whether the nodule was an associated finding or a causal or pathogenic element in the MPS and whether or not its disappearance is essential for the effective treatment.
The diagnosis of the myofascial pain syndrome is thus relied on the CLINICAL HISTORY and the PHYSICAL EXAMINATION of the soft tissue by a trained clinician. Then the diagnosis is based on the FINDINGS of MTrPs, especially ACTIVE ones. The patient complains of pain while the examiner presses by firm palpation a HARD TENDER NODULE. The nodules can cause muscle stiffness, dysfunction and restricted range of motion as well as autonomic dysfunction.
Also the phenomena LTR, local twitch response, which is used to confirm that an ACTIVE MTrP is not yet fully understood (snapping the taut band in a direction perpendicular to muscle fiber produces quick contraction in the muscle fibers).
There are also studies that claim that the nodules would present a SEA (Spontaneous Electrical Activity). First, it was attributed to dysfunctional muscle spindles and, later, to the “endplate noise”, there is also controversy about that. So there seems not to be an advantage to using electromyography.
Stecco focuses on the fascia and the role of the dysfunction of hyaluronic acid that is located in the loose connective tissue.
Quinter and Cohen relate the formation of the MTrPs to a sensitization of the nervi nervorum of affectation of the peripheral nerves.
Sikdar et al. demonstrated that the nodular regions can be seen as hypoechogenicity on sonography.
Simons had a theory of the high levels of ACh and ischemia that would evoke the release of neuroreactive substances and metabolic byproducts (BK, SP, 5-HT).
Shah et al. hypothesize that certain mediators could provoke a peripheral sensitization. And they also explain some theories that explain the “central sensitization”.
They also wonder if the latent MTrPs (just painful on deep palpation) could refer pain to distant locations. They theorize that the latent MTrPs could send a kind of sub-threshold potentials that sensitize the dorsal horn.
The authors also mention the pain perception theories:
-Integrated Hypothesis of the local milieu of the MTrPs
-Gate Control Theory Pain by Melzack and Wall
-Neurogenic inflammation and limbic system dysfunction
The review about the treatment of the MTrPs
There have been many treatments: postural exercise, heat, cold, stretch, fluoromethane spray, electrical stimulation, needling, acupuncture, etc.
Travell and Simons treated the MTrPS with injection with local anesthetics. They were influenced by Kellgren’s work (1938) utilizing injections with procaine to treat “myalgia”. However, in the 1930-1940s, the use of local anesthetic raised several concerns about muscle necrosis, fatal anaphylactic shock, and dose-related toxic effects by cumulative doses. Then, Travel and Simons took measures to utilize this technique.
They then develop the technique of SPRAY-AND-STRETCH (1983): they use the ethyl chloride spray, which distracts the patient and then they stretch the muscles. They called it the “workhorse” of the myofascial therapy. If the spray-and-stretch did not work, then they used the local anesthetic injection.
-In 1950, Sola and Kuitert used SALINE INJECTIONS to deactivate MTrPs (which lacked the risks of anesthetics).
-Frost et al. (1980) reported in a double-blinded comparison that 80% of patients reported pain relief with saline injections compared to 52% with injections with mepivacaine.
-In 1979, Lewit developed the technique of DRY NEEDLING (nevertheless, according to Shah the technique was quite painful, because of the needle size).
-Baldry (1989) developed the technique to use acupuncture needles, and even developed the technique to insert the needles around the area of the MTrPs.
-The use or the FLUOROMETHANE SPRAY also ceased due to its problems.
– Manual therapies: in 1981, Jones developed the positional release technique, ischemic compression, and transverse friction massage.
-In the 1980s and 1990s, there was interest in the TENS, ultrasound and laser.
-In 1981, Keefe introduced Biofeedback and also relaxation techniques.
Published in March 2019 by Marta Cañis Parera
-Shah et al. Myofascial Trigger Points then and now: A historical and scientific perspective (free on line Author Manuscript doi: 10.1016/j.pmrj.2015.01.024)