Dry needling is a technique used by trained physical therapists to alleviate pain in the musculoskeletal system. It is not to be confused with acupuncture, which utilizes needles over set points on the body to holistically treat imbalances in the bodily systems.
So acupuncture is mainly done by Traditional Chinese Medical Practitioners, requires a different set of skills, treats systemic issues within the body and may be followed up with diet plans or prescribed herbal medicine, and dry needling is purely for treating the musculoskeletal system via stimulation of nerves.
So what does the needle do?
When I prick you with a needle, I am stimulating your bodies natural response to pain.
Every time you get injured, your body gives you pain as an indicator to let that injury heal. So pain isn’t actually a bad thing, right? Pretty cool. For example, if you got a paper cut, your brain quickly utilizes all it’s processes to understand what has happened, it may go:
‘I’ve done this before, I survived and it didn’t impact me too much, I won’t get stressed….. but if they keep touching it… they’ll disrupt the clotting and it won’t heal, so every time they touch it….. I’ll make it a little painful.’
But back to the needle, same thing happens (hopefully!) some people have bad experiences with needles or have a fear of them (it could be a conscious or an unbeknownst to the person) and your body may read that as:
‘this needle is a threat and you need to run or fight…’
but because you have other parts of your brain that are more civil and conditioned, you don’t do that….. but the chemical reaction still primes your body to run or fight.
This unfortunately can lead to you fainting.
But if you don’t have that reaction, your body goes:
‘What was that?’ collects information from another part of your brain ‘
‘I’m in a treatment room, she said this will help me…. yeah okay, this is fine, no pain.’
When your brain says ‘Yeah ok, fine, no pain’ it stimulates a chemical to be released into your spine. This can cancel out the sensation of pain that is being sent to your brain through the spinal level that is concurrent with the area of your pain. Pretty cool!
People did argue this was a placebo response because of the whole ‘I am a therapist and told you this will help’ notion, but science is getting better at watching what happens with these nerves, the brain and the spine and what chemicals are released. This is how we know the mechanisms behind the results we see which is pain reduction.
For another good analogy of how our brain processes and makes us perceive pain, check out this wonderful engaging TEDx video by Lorimer Moseley: https://www.youtube.com/watch?v=gwd-wLdIHjs
But now……do you want the fancy version? *Raises eyebrows* Read on….
For those that want the nitty gritty and love a bit of neuroscience…..
Dry needling works by a theory called gate-control theory. This theory was proposed by Melzack & Wall in 1965 and further solidified throughout the 1970’s as the leading theory in pain perception.
Gate control theory pertains to how pain is perceived through tissues, aka. Nociception. Nociceptive cells are either a-delta or c-fibres.
This image depicts the process of nociception. It shows a a nociceptive cell being stimulated somewhere in the right side of a bodies tissues, the afferent (or feeling nerve fibre) travelling to the back of the spine (dorsal horn) on the right, synapsing with a second order neuron and travelling up the spinothalamic tract to the thalamus where it further synapses with a third order neuron to be taken to other parts of the brain responsible for collating further information about the pain (past memories of pain, visually what’s happening, position sense and feel etc).
Nociception is a natural and protective mechanism elicited by the body, therefore it is not to be eradicated or ‘cured.’ It is to correct an over-stimulation or hypersensitivity (allodynia or hyperalgesia) to non-noxius stimuli (such as light touch or movement).
Gate control theory is when slower smaller un-myelinated c-fibres have been proliferating down afferent sensory fibres in the peripheries from a tissue (such as a trigger point) and onto the dorsal root ganglion are cancelled out by the stimulation of faster larger myelinated a-delta fibres, stimulated by the needle.
A Summary of the differentiation of A-Deltas from C-FibresC-fibres respond to many stimuli and are therefore easy to stimulate and are referred to as polymodal, they are found mainly in the central nervous system. They travel from the dorsal horn up many tracts to reticular formation in the brain.
A-delta fibres are found in fascial layers just under the skin and require high thresholds to stimulate them, they are also responsive to thermal and mechanical stimulus. They travel from afferents, to the dorsal horn, up the spinothalamic tract and straight to the thalamus.
When you insert a needle into an area under the fascial layer, you present a strong enough stimulus to trigger A-delta fibres. This then has an excitatory effect on the waldeyers cells or neurons (inside the dorsal horn), which then transmits a signal up the spinothalamic tract to the thalamus where it is perceived as conscious. The second pathway that is stimulated, is an excitatory pathway onto a stork cell (also inside the dorsal horn lamina). When the stork cell is excited, it releases enkephalin, an inhibitory neurotransmitter that acts on the substanstia gelantinosa.
When someone is having constant bombardment of c-fibres being stimulated, it has an excitatory effect on the substantia gelantinosa (and is a part of becoming centrally sensitised and having a higher receptive field for receiving and transmitting pain to the conscious brain). The enkephalin release from the stork cell is inhibitory and negative, therefore the neuron is now at neutral due to the positive potentiation of the c-fibres (the negative and positive interaction results in neutral).
Gate Control Theory, a Summary: A C-fibre is triggered causing it to neuro-transmit down to the dorsal horn of the spinal cord, where it transmits and excites the substantia gelatinosa, causing it to release more neurotransmitters (chemicals) that make the dorsal horn of the spinal cord more sensitive or receptive to C-fibres. If this proliferates, this can cause neuroplastic change and make the dorsal horn more receptive to feeling C-fibres, hence pain. An A-delta fibre is stimulated when a needle is inserted. This A-Delta transmits down two pathways: 1 onto a waldeyers cell in the dorsal horn straight up the spinothalamic tract to the thalamus where the ‘prick’ is made conscious. 2 onto a Stork cell in the dorsal horn which causes the cell to release enkephalin, a inhibitory neurotransmittor. This inhibits the substantia gelatinosa from re-uptaking more C-fibre neurotransmission, which in turn blocks the excitatory effect onto a transmittor cell and the process of C-fibres being perceived in reticular formation in the brain.
Hope this clears some mysteries and misconceptions about dry needling up, or primes you for experiencing what dry needling can do for you.
Wishing all health, wellness & success,
Jess Jelleff
BhSc. Clinical Myotherapy
CEO of Affinity
References:
Moseley, L. (2011). TEDxAdelaide, Lorimer Moseley – Why Things Hurt [Video]. Adelaide, Australia: TEDTalks. https://m.youtube.com/watch?v=gwd-wLdIHjs
Image Sources in Order of Appearance:
https://commons.wikimedia.org/wiki/File:Afferents.png
