Dry Needling: Panacea or Placebo? (Part I)

Dry needling is the latest panacea in the therapy world that is neither physical nor therapeutic, and is backed by an absolute treasure-trove of largely mixed studies, both in results and quality.  So why is it so popular?  Why do I need to see continuing education courses on my Facebook feed all the time?  Is it really in our scope of practice?  According to the APTA’s educational resource paper on the subject,

“dry needling is a skilled intervention that uses a thin filiform needle to penetrate the skin and stimulate underlying myofascial trigger points, muscular, and connective tissues for the management of neuromusculoskeletal pain and movement impairments”

(Descriptions of Dry Needling In Clinical Practice, 2013, pg 2)

Practitioners of dry needling stick needles into spots that hurt.  That’s it.  Maybe there are few different techniques like varying the depth of penetration or the angle of insertion, or moving the needle in different ways, but they are still just sticking needles in you.  As for exactly what that does for painful musculoskeletal conditions, researchers are less than sure.  According to Furlan et.al. “it is still unclear what exact mechanisms are underlying the actions of acupuncture or dry needling” (Furlan, 2005, p. 945).  Here are some of the proposed mechanisms:

• The good old gate control theory of pain
• Opioid-mediated pain suppression
• Normalization of altered chemical concentrations in muscles
• Elicitation of a local twitch response that has analgesic effects by interrupting motor end plate noise

(Furlan, 2005, p. 945), (Descriptions of Dry Needling In Clinical Practice, 2013, pg 2)

Despite uncertainty in what it actually does, proponents of dry needling position it as a treatment that helps for all types of problems. According to Kinetacore, one of the largest continuing education groups for expensive dry needling courses, it can be useful for “tendonopathies, movement impairments, hematomas, muscle tears, compartment syndrome, shin splints, rotator cuff injuries, medial and lateral epicondylitis, piriformis syndrome, sciatica, patellofemoral syndrome, patellar tendinitis, hamstring strains, groin strains, thoracic outlet syndrome, carpal tunnel syndrome, and impingement syndrome” (http://www.kinetacore.com/faq/).  That is a pretty exhaustive list, isn’t it?

Dry needling seems to have all the makings of a specious, pseudoscientific treatment: there is a reasonably plausible proposed mechanism, it has the allure associated with an ancient and mysterious treatment like acupuncture, it can be used to treat any condition, and the way we measure treatment success (less pain) is largely subjective.  If only we had something to help us determine what is really going on…like science!

Here is a stipulation when diving into this research: I will be focusing on studies with adequate blinding of the control group, or at least an attempt at it.  If a patient knows they are getting “true” dry needling instead of sham or the standard treatment, patient expectations and placebo effects can come into play.  A quick search on PEDro shows that out of the 55 clinical trials that are scored that come up when entering “dry needling,” only 18 of them actually blinded subjects.

Let’s look at the strongest study I have come across.  Published in PAIN in 2015, Sterling et.al. investigated the immediate, short term, and long term effects of dry needling and exercise versus sham dry needling and exercise for patients with chronic whiplash associated disorder.  The intervention group had 6 treatments of DN and exercise, then 4 treatments of exercise over a period of 6 weeks and the control group had the same, with sham DN.  Here is why this study was extremely well conducted:

• Patients were excluded if they had any previous experience or knowledge with dry needling
• There was random allocation to intervention or control groups via a computerized randomization process overseen by a statistician not involved with the analysis or results
• They used sham needles previously evaluated for effectiveness
• Patients were blinded to which needles they received as they only performed the treatment on posterior muscles
• The interventions were very comparable to a typical physical therapy treatment
• Exercise compliance was monitored via exercise journals
• The physical therapists were trained in the interventions and were audited
• An assessor blinded to group allocation obtained outcome measures
• Outcomes were taken at baseline, 6 weeks, 12 weeks, 6 months, and 12 months
• They used a variety of outcome measures including NDI, self-rated recovery scale, whiplash disability questionnaire, Short Form 36, Patient Specific Functional Scale, Post-traumatic Stress Diagnostic Scale, Pain Catastrophizing Scale, C/S AROM, pressure pain threshold, Cold pain threshold, and Leeds Assessment of Neuropathic Symptoms and Signs
• The person doing statistical analysis was blinded to group allocation
• They only had 7 of 80 subjects drop out
• They assessed if patients knew which group they were in and only one correctly guessed they were in the sham group, the rest did not know or believed they were in the dry needling group

So if there was ever an opportunity to show that dry needling is an effective treatment beyond the non-specific effects of placebo, this study would show it.  So what did they find? Meh.

“The results show that compared with sham dry-needling and exercise, dry needling and exercise produced statistically significant reductions in pain-related disability, pain catastrophizing, and cold hyperalgesia at 6 and 12 months follow-up, statistically significant reductions in posttraumatic stress symptoms at 6 months and small increases in pressure pain thresholds over the neck at 12 weeks. Aside from this latter measure, there was no difference between the interventions at short-term follow-ups conducted immediately after treatment and 12 weeks later. However, although being statistically significant, any effects were very small and unlikely to be clinically worthwhile” (Sterling, 2015, p. 637)

So for the majority of outcome measures, there were no differences between real dry needling and sham dry needling, and for the ones that did show a statistical difference, the benefits were so small they could not have been deemed clinically important.  A major bummer for the dry needlers.  Surely, if dry needling had any therapeutic effects beyond placebo, we would have seen them here.  If there is a more applicable and robust trial, I have not seen it.  There are plenty of other controlled trials of varying quality available, but in the interest of maintaining the consciousness of the reader, I will only go through some of the “stronger” ones (rated 8/10 or higher on the PEDro scale, despite some fatal methodological flaws) briefly.  

• Pecos-Martin et.al. 2015 investigated the effects of location-specific dry needling versus non-location-specific dry needling into the lower trapezius in patients with neck pain.  They found that dry needling into trigger points in the lower trapezius was more effective at relieving pain than dry needling to areas around the trigger point, but did nothing to ensure that patients were unable to distinguish what group they were in.  Presumably, if you have a trigger point and someone sticks a needle in it, you would know and therefore patient expectations and placebo effects may be in play here.  
• Cuoto et.al. 2013 investigated the effects of deep intramuscular stimulation therapy, trigger point lidocaine injections or a “placebo” group consisting of a deactivated electroacupuncture device (more on this later) on patients with myofascial pain syndrome.  The authors found that the deep intramuscular stimulation group was the most effective at reducing pain as compared to the other groups but the authors were not able to blind patients as to what group they were in.  In reference to the placebo group’s treatment, patients were told “they would most likely feel no sensation from it.”  A nice mix of placebo and nocebo effects could be here possibly.
• Diracoglu et.al. 2012 investigated the effects of dry needling versus sham dry needling on patients with tempromandibular joint related pain.  The dry needling group had needles inserted into trigger points in the TMJ region, while the sham group had needles only partially inserted into areas away from trigger points.  The authors found that while there were improvements in both groups and a statistically significant difference in pain-pressure threshold favoring the dry needling group, there were no differences in VAS scores or unassisted jaw openings without pain.  The authors concluded that “dry needling appears to be an effective treatment method in relieving the pain and tenderness of myofascial trigger points” but forgot to mention that it is not much better than non-location-specific and superficial dry needling.  A small lie of omission.
• Fernandez-Carnero et.al 2010 investigated the effects of dry needling versus shallow sham needling on pain pressure threshold and pain-free maximal jaw opening in patients with tempromandibular disorders.  They found that the dry needling group had significantly better outcomes than the sham group, however the study only had 6 people in each group.  While these results were positive, the sample size was far too small to make more definitive conclusions.  
• Cotchett et.al. 2014 investigated the effects of dry needling versus sham dry needling on plantar heel pain as well as foot function and foot health as measured on the FSQH, and anxiety, stress, and depression as measured on the DASS-21.  The researchers found that for pain as measured on the VAS and with the FSQH, there were statistically significant differences in favor of the dry needling group throughout the study but these changes did not reach the previously established MID.  For all other outcome measures, there were no differences between groups. However, the authors reported that in 32% of the real dry needling appointments there were “minor, transitory adverse events” like needle site pain versus only 1% in the sham needling group.  While the authors tried to assess the success of their blinding, by using the Credibility/Expectancy Questionnaire, they only used it after the first treatment.  Could the high amount of adverse events have revealed group allocation?  Do we want to be performing a treatment where a third of the sessions result in “adverse events?”

Based on the highest quality trials I could find, here is the most charitable thing I can say about dry needling thus far:

Dry needling may relieve pain, but not much better than the non-specific effects of a credible placebo treatment.

Placebo-controlled trials are not the only studies we care about however, so in part two, we will take a look at some of the meta-analyses and clinical recommendations about dry needling.    

References:

1. Description of Dry Needling In Clinical Practice: An Educational Resource Paper (2013). American Physical Therapy Association
2. Furlan, A, et.al. (2005) Acupuncture And Dry Needling For Low Back Pain: An Updated Systematic Review Within The Framework of The Cochrane Collaboration. SPINE, Volume 30, Number 8
3. http://www.kinetacore.com/
4. Sterling, M, et.al. (2015) Dry-needling and exercise for chronic whiplash-associated disorders: a randomized single-blind placebo controlled trial. PAIN, Volume 156, Number 4
5. Pecos-Martin, D, et.al. (2015) Effectiveness of Dry Needling on the Lower Trapezius in Patients With Mechanical Neck Pain: A Randomized Controlled Trial. Archives Of Physical Medicine and Rehabilitation, Volume 96, Issue 5
6. Cuoto, C et.al. (2013) Paraspinal Stimulation Combined With Trigger Point Needling and Needle Rotation for the Treatment of Myofascial Pain: A Randomized Sham-controlled clinical Trial. Clinical Journal of Pain
7. Diracoglu, D, et.al. (2012) Effectiveness of dry needling for the treatment of temporomandibular myofascial pain: A double-blind, randomized, placebo controlled study. Journal Of Back and Musculoskeletal Rehabilitation, Volume 25
8. Fernandez-Camero, J, et.al. (2010) Short-Term Effects of Dry Needling of Active Myofascial Trigger Points in the Masseter Muscle in Patients With Temporomandibular Disorders. Journal Of Orofacial Pain, Volume 24, Number 1
9. Cotchett, M, et.al. (2014) Effectiveness of Trigger Point Dry Needling for Plantar Heel Pain: A Randomized Controlled Trial. Physical Therapy, Volume 94,  Number 8