Dry Needling: More Info

How does dry needling work?
While most patients are typically curious to know if it works, there are some patients who also want to understand how it works.  The effects of dry needling are not completely understood, but are believed to be associated with altering the activity of receptors within muscle called muscle spindles.

Most of the fibers within a muscle generate force.  However, there are a small number of fibers in most of the muscles of the body known as intrafusal fibers, which act as sensory receptors, detecting changes in muscle length and tension within the muscle.  These intrafusal fibers, along with the nerves that innervate them (gamma motor neurons) are located within a fibrous capsule called the muscle spindle. When the muscle spindle is activated, it creates tension within the muscle. 

Normally, this serves as a protective mechanism to ensure that the muscle is
not overstretched or ruptured, but sometimes this mechanism can become
overactive, resulting in muscle hyperactivity or spasm.  This is very common in
spinal disorders due to the very high concentration of muscle spindles within
spinal muscle.  It is also common in the presence of nerve disorders, which
may result in changes in activity of the muscle spindle.

In many cases, a spasming muscle will have a palpable taut band which is sensitive to the touch, called a trigger point.  Trigger points are often a cause of pain.  It is believed that the sustained increase in tension in the muscle results in pressure on the small circulatory vessels – arterioles, venules, and capillaries – within that part of the muscle, resulting in decreased blood flow and oxygen delivery, as well as accumulation of cellular metabolites (“waste products” from cellular activity) which are normally freely carried away.  When this happens, the patient may often experience a persistent, “burning” sensation, similar to the burning felt during vigorous exercise.

Needling into trigger points has been consistently demonstrated in both clinical practice and scientific research to normalize muscle activity and decrease symptoms associated with muscle spasm and trigger points.  It is unclear exactly how dry needling alters the muscle spindle.

While Mike has a firm grasp of the theory behind dry needling and respects how theory can influence clinical decision-making, Mike also believes that successful treatment outcomes depend most on the skill of the practitioner and not just the theory behind them.  Choosing a practitioner with extensive experience in orthopedic and manual physical assessment increases the odds of successfully identifying and treating trigger points, as well as decreasing the odds of adverse outcomes such as needling in a harmful location.



Can dry needling be used to treat conditions other than trigger points?
While dry needling treatment is often directed at overactive muscles, there are other possible applications, including tendinitis.

Tendons are rope-like structures created by interwoven strands of collagen which form into various sizes of bundles (small bundles combine to form intermediate bundles, and intermediate bundles combine to form large bundles), much like the fibers of a rope.  Injured tendons demonstrate more irregularity of collagen fiber alignment than healthy tendons, and this may result in decreased mechanical efficiency and capacity of the tendon.






                                      Above: normal (A) and abnormal (B) tendon viewed under a microscope

Dry needling has been shown to create changes in collagen fiber
alignment.  The evidence for this is strong, and includes microscope
studies using tissue samples before and after dry needling.  This is
especially true when needles are wound, creating a “fork in a bowl of
noodles” type effect. As a result, dry needling is an ideal treatment
for creating positive changes in tendon fiber alignment – a critical
part of tendon health and function

.Mechanical stimulation with small, sharp needles is known to cause increased collagen production in skin.  Dermatological studies have demonstrated that micro-needling procedures can result in a large increase in the production of collagen in human skin.  The exact mechanism for this is unclear, but it is possible that other tissues, such as tendon, may demonstrate a similar response of collagen proliferation in response to needling.

Beyond the theory, there is real-world evidence from
peer-reviewed studies which demonstrate improved
clinical outcomes when using dry needling in patients
with Achilles tendinitis, plantar fasciitis, and tennis elbow.

(Right: increased volume of collagen fibers (stained red) seen in
skin following microneedling procedure