Trigger Points – Myofascial Pathology or a Fight Starter?
By Aran Bright
Trigger points are a core principle in musculoskeletal pain. Since Travell and Simons instigated the concept it has been fundamental to any professional in musculoskeletal health. But trigger points have become more than a cause of myofascial pain – they lead to some of the most heated arguments amongst doctors, physios, massage therapists and scientists.
What Can We Agree On?
There isn’t a huge amount the experts agree on about trigger points, but here are some commonly agreed theories on what a trigger point is:
- A point in a muscle that is hypersensitive to touch
- A feeling of a nodule or band of muscular tightness
- Pain referral that can be aching, deep, burning and variable in sensation.
Many experts also agree that recognition of pain is important in identifying a trigger point that could be described as “active”.
However, no one seems to agree that a referral pattern is predictable and consistent from one person to the next.
It does appear that trigger point locations tend to be consistent from one person to the next, which brings us to the main topic of debate …
What Is A Trigger Point (apart from something that starts epic social media arguments)?
There are two main camps:
Muscle lesion – this model is based around concepts such as motor end plate hyperactivity causing continued muscle spasm or micro tears in the muscle structure, leaking calcium ions and triggering local contracture. (This is most likely the birthplace of the most horrendous of myths around “calcium balls” that need “breaking up” to “release” the muscle.) This is where the concept of ischemia or poor blood flow to muscle comes from: essentially, if the muscles spasm, it chokes the local area of blood flow. (Source)
Neuropathy – the main opponents to the muscle lesion model of trigger points contend that the muscle lesion model is, at best, a hypothesis that has never been conclusively proven. It appears that the best evidence around trigger points tends to be either sonographic or electromyographic, which is hardly conclusive as to what the physiology of a trigger point actually is. As far as this author can tell, no one has ever actually “seen” a trigger point, except through ultrasound imaging.
What is contended by the opponents to the traditional model of trigger points is that we should be considering other potential causes for trigger points that are more directly related to the nerves themselves, such as a neuritis (nerve inflammation) or peripheral nerve sensitisation.
The best summary to better understand the opposition to the muscle lesion model is the Critical Evaluation of the Trigger Point Phenomenon.
Why Does It Matter?
It is tempting to think, who cares? Most experts agree that trigger points are real, they hurt, and we can make them better with massage or whatever method we choose to treat them. There is some truth to this but, if we assume that there is some muscle lesion or dysfunctional motor end plate, then we should be choosing the most effective method in our toolbox to address it. Likewise, if the problem is more a product of the nervous system, then we should be choosing the method that is most suited to this physiology.
To demonstrate this point let’s explore one of the hot treatment approaches right now.
Dry needling is definitely not new – any acupuncturist reading this will quite possibly be throwing things and screaming “4000 YEARS!” Dry needling is a product of Travell and Simons who actually proposed using hypodermic injection of anaesthetic into the site of a trigger point. At some point, someone got either cheap or lazy and started using thinner filiform acupuncture needles, and dry needling was born.
The theory behind dry needling is that the needle penetrates the muscle lesion and destroys the motor end plate. This is typically performed with a perforating or thrusting technique of the needle that is often quite painful and invasive.
Now, if it is truly the case that there is a muscle lesion, then should it also be the case that deep dry needling should be superior to, say, a thumb?
Well, here is where things get tricky. On the surface, the evidence does seem to suggest that dry needling is better than other approaches. For example, a systematic review of trigger point dry needling by Gattie, Cleland and Snodgrass in the Journal of Orthopaedic and Sports Physical Therapy states:
“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 and improving pressure pain threshold in patients presenting with musculoskeletal pain in the immediate to 12-week follow-up period.”
Reading deeper into the article, you will discover this statement in the conclusion:
“Although findings of this review provide very low– to moderate quality evidence for the effectiveness of dry needling for reducing pain and improving PPT when compared to other physical therapy interventions during the immediate to 12-week follow-up period, the small effect sizes and the varied study populations and comparison interventions utilized do not support a strong recommendation of dry needling over other physical therapy interventions.”
The article goes on to state that the general “superiority” of dry needling is just over 1 point on the visual analogue scale. As an example, if someone received massage for a trigger point, they might see a pain reduction from 8 to 5, with dry needling, they would expect to see 8 to 4. Considering the extra muscle perforation and discomfort involved in dry needling, not to mention the risks, is that really worth it?
Does dry needling demonstrate clinically meaningful effects that would be an indication that there is a muscle lesion of some sort? The most generous conclusion would be that this is yet to be demonstrated.
An Alternative Approach
To avoid getting too much deeper into a science wormhole, the Gattie et al systematic review did demonstrate that manual techniques were effective in reducing myofascial trigger point pain.
The purpose of this blog is to hopefully open your mind as to why.
The best answer is, we don’t know.
Anyone stating with absolute certainty that they know what a trigger point is should be viewed with some scepticism.
We should be considering alternative explanations, and hopefully ones that don’t involve repetitive thrusting with sharp pointy things.
To provide you with some sense of what might be going on when you press on a trigger point and the pain is reduced, please consider two theoretical mechanisms that have undergone significantly more investigation than trigger point physiology and are much more broadly accepted by neuroscientists and scientists in general.
Descending Inhibition – this is the current mechanism that is proposed (and has been around for about as long as trigger points) for the effects of manual therapies such as massage. Basically, it is the “turning down” of nociceptive pathways at the level of the spinal cord.
It goes a little something like this:
Massage Therapist: *Presses firmly on tender trigger point*
Nerve Ending: *stimulated*, *sends message to the spinal cord along sensory nerve*
Sensory Nerve: *sends signal to brain*
Brain: *interprets message as pain*
Brain to self: “Hmm, even though sensation is painful, it is occurring in a safe, therapeutic space.”
Brain to Sensory Nerve: “Thanks very much for that information but I am kinda busy soaking up this massage.”
Brain: *turns down the pathway to that sensory nerve at the spinal cord so it can still hear it but just in the background*
Brain: *goes back to “soaking up” massage*
Client: *experiences a “release” regardless of what actually happens to the muscle*
Diffuse Noxious Inhibitory Control – This is most likely what is going on when someone receives intense needling, extreme instrument assisted soft tissue manipulation or one of those torture sessions that some people confuse as massage.
Client: *receives intense sensation to the sensory nerves* “Ouch!”
Spinal cord: *fast tracks intense sensation to the brain*
Brain: “WTF!” *runs straight to internal medicine cabinet and grabs whatever it can find (generally a mixture of endogenous opioids)*
Brain: *gets drunk and ignores irritating sensory nerves*
Client: In some cases, the client will experience a reduction in symptoms.
Massage Therapist: *sees themselves as some kind of demi-god – kind of a mixture between Maui and Thor*
Trigger points are real, no one questions this, but what they are is unclear.
It is important that we consider all the options on the table as it is likely to be “a little from column A and little from column B”.
The mechanisms by which we treat trigger points should also be viewed with an open mind. Massage works, dry needling works, but the best methods are probably yet to be defined. Please remember: our best understandings of why massage and manual therapies reduce pain are functions of the nervous system, not fixing some part of a muscle.
Article by Chang-Zern Hong, MD and David G. Simons, MD “Pathophysiologic and Electrophysiologic Mechanisms of Myofascial Trigger Points”
About the Author
Aran Bright started his career as a massage therapist in 2002 after graduating from the Australian College of Natural Medicine in Queensland. In 2006, Aran completed his Diploma of Remedial Massage and, in 2007, his Bachelor of Health Science in Musculoskeletal Therapy. Aran graduated from University of Queensland with a Graduate Certificate of Sports Coaching, completed a Certificate IV in Fitness and an Advanced Diploma of Myotherapy. He currently runs his own businesses, Bright Health Training and Brisbane Workplace Massage, with his wife, Sheree.