The Treatment Technique Known as Dry Needling
The Treatment Technique Known as Dry Needling
Dry needling is a treatment technique that has been used for centuries across the world, but it has only recently gained popularity and acceptance in the United States. A description of dry needling can be found dating back two thousand years ago in the book Huang Ti Nei Ching, which illustrates that, while dry needling is said to have been created more recently by pioneers in their field, the practice is an ancient one. Dry needling is based on several different theories, the most popular being the trigger point and the radiculopathy models. Dr. Janet Travell is credited with the development of the trigger point hypothesis in 1981, which the trigger point model, along with many manual techniques, is based. In 1983, Travell and Simon described the trigger point as being a taut band of muscle with a specific radiating pain pattern. In 1979, Karl Lewit used dry needles to penetrate these myofascial trigger points, with a technique known as deep dry needling; needles penetrate past skin and subcutaneous tissue into the targeted muscle. Another practitioner, Peter Baldry, practiced deep dry needling until he had a patient in the early 1980’s with a trigger point in his anterior scalene muscle. Baldry decided to only penetrate the skin for fear of puncturing a lung. Baldry has such success with this technique that he applied it throughout the body by simply puncturing the skin superficially over a trigger point without actually reaching it. This technique was termed superficial dry needling. Then, in 1989, Dr. Chan Gunn, also a practitioner of deep dry needling, put forth a different theory on how it works and where it should be applied on the body called the radiculopathy model. Dr. Gunn believed that the peripheral muscle spasm was not the origin of pain, but instead a tight multifidi was causing spinal nerve compression, radiculopathy, and nerve damage running peripherally. This spinal nerve damage eventually reached the associated muscle, causing spasm and transformation to a trigger point. Therefore, Gunn recommended a needle be placed in the paraspinal muscles in addition to the distally affected muscle. In 1990, Dr. Jennifer Chu developed electrical twitch-obtaining intramuscular stimulation (IMS), also known as percutaneous electrical nerve stimulation, which is the addition of electrical stimulation in the needle itself; this method claims to be superior to TENS since the needle is deeper than the electrodes that are only able to sit on the skin above the trigger point. Most recently, Dr. Fu developed the floating needle or subcutaneous needling technique in 1996, where the needle is surrounded by soft tubing, and both are inserted into the subcutaneous tissue. The needle is then removed and the tube remains for 2 to 24 hours.
Today, there are numerous practitioners who use dry needling techniques across the world, as well as many schools dedicated to educating future practitioners. Edo Zylstra and Dr. Yun-toa Ma are some of today’s most noted dry needling specialists, both of whom have created education courses and teach internationally. Zylstra was trained in Travell and Simon techniques and is certified in Chan Gunn’s intramuscular stimulation technique. He developed and teaches an introductory course and two advanced courses in intramuscular manual therapy. Dr. Ma created a course called Integrative “Dry Needling: the Orthopedic Approach” which combines Dr. Travell’s trigger point dry needling and Dr. Gunn’s IMS approach. He is also the founder of the American Dry Needling Institute and has been teaching worldwide for 40 years.
Regardless of the different models and needling techniques, the procedure is very similar at its core. The practitioner begins with an interview and examination where he/she checks for motor changes, signs of neuropathic pain, palpable muscular bands, tropic changes, and active or latent trigger points. Active points spontaneously trigger pain, while latent points only trigger pain when stimulated. Once a trigger point is found, the practitioner places a needle, either on a 20 degree angle or perpendicular to the patient, and then penetrates either skin deep or into the taut muscle band. The needle can remain inserted for anywhere from 30 seconds to 5 minutes; then, if the Fu technique is being used, the soft tube can remain for up to 24 hours. If the needle does penetrate the muscle, a local twitch response is common and theoretically indicative of the healing process. Additionally, electrical stimulation can be added to the needle to create this twitch response, hopefully returning the muscle to its resting state. Lastly, the needle is removed and discarded and the patient should feel immediate, possibly lasting, pain relief.
Dommerholt, J., Mayoral del Moral, O. & Grobli, C. (2006). Trigger point dry needling. The Journal of Manual & Manipulative Therapy, 14; 4: 70-87.
The most popular school of thought for use of the various dry needle treatments is the Travell trigger point theory. When a muscle becomes injured or overworked, a section of the fibers may become shortened, creating a fibrous band that is tender to palpation and, perhaps, during movement activities that utilize the affected muscle. Fibers are shortened due to a release of excess acetylcholine (ACh) into the neuromuscular junction as a response to injury.2 This sustained shortening is followed by decreased oxygen supply to that section of muscle, which encourages release of pain-inducing (nociceptive) chemicals such as bradykinin, calcitonin, and substance P. Release of these substances enhances the pain associated with the damaged tissue by stimulating the afferent C-fibers, creating what is referred to as a muscular or myofascial “trigger point”, or MTrP.2 Trigger points can be caused by muscle imbalance, postural deficits, or even vertebral disc herniations.3 Muscle pain or headaches are common side effects3, which can decrease patient function, affect, and quality of life. Many treatment approaches are available for patients with trigger points, varying between manual therapy, invasive procedures, exercise, and numerous modalities.
Dry needling for the treatment of MTrPs is based on theories similar to traditional acupuncture; however, dry needling targets the MTrP, which is the direct and palpable source of patient pain, rather than the traditional “meridians”, accessed via acupuncture. Just like there are various methods to dry needling, there are various theories concerning the mechanism of action in how or why the procedure may work. The most popular theory is the spinal cord and brain model of action. When the needle is inserted into the MTrP, a local twitch response, LTR, is elicited from the muscle. A twitch is considered the “proper” response from the MTrP, suggesting the appropriate area has been stimulated, creating a spinal reflex reaction that untangles the actin and myosin to encourage resting position in the muscle. Type II, III, and IV afferent fibers are stimulated in the muscle and transmit the stimulation to the spinal cord, while A Delta fibers transmit the same stimulus from the skin. Enkephalin and dynorphin, opioids created in the body, are released in the spinal cord and block any ascending pain. When the stimulus is transmitted to the midbrain, enkephalin blocks descending pain along with serotonin and norepinephrine. Then stimulus continues to travel to the hypothalamus, where B-endorphin is released from the arcuate nucleus, continuing to dampen descending pain transmission. The pituitary reacts to the hypothalamus’ endorphin release by secreting its own endorphin and adrenocorticotropic hormone (ACTH); these chemicals enter the systemic circulation and cause anti-inflammatory responses, further decreasing pain.
While the spinal cord theory is well respected, there are additional thoughts behind the varied success of dry needling. The mechanical twitch response in the muscle may cause nitric oxide release that opens capillaries and leads to improved blood flow to the contracted muscle, inducing a healing effect. It has also been shown that needling without inducing a twitch response can improve blood flow, blood volume, and oxygen saturation to treated muscle and tendon; the effects were shown to be similar to those of heating the affected tissues, but needling displayed longer lasting results.5 Theories surrounding the proposed and clinically relevant effects of dry needling are well-founded, however, patient experience and research results continues to provide mixed outcomes, creating a need for continued review and experimentation.
According to the APTA Department of Practice and APTA State Government Affairs, “The performance of dry needling by a physical therapist may be determined by the state regulatory board to be allowed, provided that the physical therapist is competent to do so, and does not profess to be engaging in the practice of another profession.”6 For example, physical therapists performing dry needling may not refer to it as acupuncture, unless the clinician is in fact a licensed acupuncturist. As of December 2011, several states have issued opinions affirming that dry needling is within physical therapists’ scope of practice. A few of these states include Georgia, Colorado, Kentucky, and Maryland, with Georgia being the first state to specifically include dry needling in its state practice act in May 2011. Conversely, state boards including New York, Pennsylvania, and Florida have decided that dry needling is not within the scope of practice. Requirements to practice dry needling with competence vary from state to state, with only a handful of states having published guidelines outlining education and competency standards. Requirements range from a minimum of 50 hours of dry needling instruction and a competency assessment, to two years of practicing as a licensed physical therapist prior to using the dry needling technique.7 Because the requirements vary from state to state, it’s imperative that physical therapists interested in dry needling abide by their state practice acts. While it’s acknowledged that dry needling is not an entry-level skill, more jurisdictional boards must create methods to determine that a physical therapist is competent to perform the task.
Although dry needling is a relatively new technique in physical therapy, there are numerous research articles addressing this topic, including many control trials and a few systematic reviews. However, many of the studies conducted on dry needling appear to be of low quality. In addition, many of the studies also included acupuncture because the two techniques are thought to be very similar. There is a distinct difference between dry needling and acupuncture, though, which lies in the location of the application of the needle. Acupuncture follows a range of traditional theories of Chinese Medicine and the targeted location for acupuncture needles follows meridians of the body; dry needling targets specific trigger points, the MTrPs, within the muscle. There seems to be a high degree of correspondence between trigger points and traditional acupuncture points, trigger points being most like the “a-shi” points used in acupuncture, but the two terms should not be used interchangeably.
Many of the studies published about dry needling are not strong; either the studies were not randomized, contained small sample sizes, had high dropout rates, used active interventions in the control group, did not follow the minimally acceptable criteria for diagnosing a myofascial trigger point, or did not clearly state that myofascial trigger points were the sole cause for the pain. For example, in a systematic review on needling therapies in the management of myofascial trigger points, only 8 of the 23 trials described the minimally acceptable criteria for diagnosing a trigger point.9 Locating the trigger point for dry needling is the basis for performing dry needling and should therefore be documented in each study performing this technique. In the same review, two studies tested the efficacy beyond placebo of dry needling in the treatment of MTrP pain, but, in one, the dropout rate was 48% and it was neither blinded nor randomized, and the other study used potentially active interventions in the control group. Potentially active interventions are hard to avoid in a study involving dry needling techniques because the mechanism of action seems to come from the insertion of the needle itself. Because of this, a placebo needle could have the same effect as the acupuncture needle used in dry needling. Consequently, this is a weak point in determining the effect beyond placebo of trigger point needling, but new solutions are emerging; these new “controls” include blunted needles with telescopic handles. These needles have shown to be a valid placebo, and should be used in future studies when determining the effect of dry needling beyond a placebo effect.
It has been suggested that dry needling should not only be used directly in the myofascial trigger point, but also at an indirect site, such as another point within the muscle or within the paraspinal musculature adjacent to the associated spinal level of the muscle involved. Two studies examined in a review of dry needling in the management of musculoskeletal pain produced contradictory results regarding this topic and four others failed to show that needling directly into a MTrP is superior to various sham interventions.13 A study done by Ga, et al. showed that paraspinal dry needling in addition to myofascial trigger point needling resulted in more continuous subjective reduction of pain at follow-up than dry needling into the myofascial trigger point alone in elderly patients.11 Other studies have compared the effects of deep dry needling versus superficial dry needling, which involves inserting the needle superficially into the tissue immediately overlying the MTrP rather than into the trigger point itself. Two studies found that superficial dry needling is superior to no intervention or placebo in reducing pain, but a study by Naslund, et al. found that there was no statistical difference between superficial dry needling and deep dry needling for idiopathic anterior knee pain.10,14,15 Deep dry needling is theorized to produce an analgesic effect by disrupting the nocioceptive afferent signals by mechanical stimulation. Although the superficial method does not enter the myofascial trigger point, and therefore, creates no local twitch response, it may produce the analgesic effects by activating polymodal receptors found in the skin and disrupting those nocioceptive afferent signals.13 Therefore, it can be concluded that both methods may benefit a patient with myofascial trigger point pain.
Regardless of the low quality of the many studies involving dry needling, most have found similar conclusions. Many studies have reported evidence of pain relief and functional improvement with dry needling compared to no treatment in various parts of the body (chronic low back pain, TMJ pain, plantar fasciitis, etc.) Pain relief in patients with TMJ pain was significant and lasted throughout the six month post-treatment follow-up from dry needling in the external pterygoid muscle.12 However, the effects for chronic low back pain were short-lived only through short-term follow-up. A systematic review of the effectiveness of dry needling and injections of myofascial trigger points associated with plantar heel pain examined four studies of quasi-experimental design, which all found a decrease in plantar heel pain after being treated with dry needling.8 However, two of these studies combined trigger point dry needling with acupuncture, making it difficult to isolate the effectiveness of the dry needling technique. Additionally, all four trials included in this review were considered to be of low quality due to either the lack of a control group, no attempt to blind the data collectors, or failing to describe the criteria used to identify a myofascial trigger point, which has been a consistent finding in other systematic reviews of dry needling.
In conclusion, most studies have derived that dry needling is an effective treatment for musculoskeletal pain and myofascial trigger points, even as effective as an analgesic injection into the painful site. There are numerous studies on the use of dry needling for musculoskeletal pain and myofascial trigger points, but more research needs to be done on the effect of dry needling in comparison to a placebo. Although there have been difficulties in the past finding an appropriate placebo for this type of study, the invention of the blunted needle with a telescopic handle seems to be a promising option. Future studies should aim to be of higher quality than the current available literature, and should include randomization, a control group, blinded subjects and data collectors, larger sample sizes, and a clear description for diagnosing a myofascial trigger point. Additionally, the future systematic reviews on this topic should include trials with similar needle depth of insertion, location of needle placement, individual treatment times, and overall number of treatment sessions.
1. Dommerholt, J., Mayoral del Moral, O. & Grobli, C. (2006). Trigger point dry needling. The Journal of Manual & Manipulative Therapy, 14; 4: 70-87.
2. Osborne N, Gatt I. Management of shoulder injuries using dry needling in elite volleyball players. Acupuncture In Medicine [serial online]. March 2010;28(1):42-45. Available from: CINAHL with Full Text, Ipswich, MA. Accessed August 22, 2012.
3. Huguenin, L. K. (2004). Myofascial trigger points: The current evidence. Physical Therapy in Sport, 5(1), 2-12. doi: 10.1016/j.ptsp.2003.11.002
4. Davis, C. (2009). Complementary therapies in rehabilitation: Holistic approaches for prevention and wellness. (3rd ed., pp. 334-36). Thorofare, NJ: SLACK Incorporated.
5. Kubo, K., Yajima, H., Takayama, M., Ikebukuro, T., Mizoguchi, H., & Takakura, N. (2010). Effects of acupuncture and heating on blood volume and oxygen saturation of human achilles tendon in vivo. European Journal of Applied Physiology, 109(3), 545-50. doi: 10.1007/s00421-010-1368-z
6. American Physical Therapy Association. Physical Therapists & the Performance of Dry Needling: An Educational Resource Paper. Available at: www.apta.org/StateIssues/DryNeedling/ResourcePaper/. Accessed on August 24, 2012.
7. Is Dry Needling in Your Scope of Practice? Available at: http://www.kinetacore.com/physical-therapy/Is-Dry-Needling-In-Your-Scope.... Accessed on August 25, 2012.
8. Cotchett MP, Landorf KB, Munteanu SE. Effectiveness of dry needling and injections of myofascial trigger points associated with plantar heel pain: a systematic review. J Foot Ankle Res. 2010;3:18.
9. Cummings TM, White AR. Needling therapies in the management of myofascial trigger point pain: a systematic review. Arch Phys Med Rehabil. 2001;82(7):986-92.
10. Edwards J, Knowles N. Superficial dry needling and active stretching in the treatment of myofascial pain--a randomised controlled trial. Acupunct Med. 2003;21(3):80-6.
11. Ga H, Choi JH, Park CH, Yoon HJ. Dry needling of trigger points with and without paraspinal needling in myofascial pain syndromes in elderly patients. J Altern Complement Med. 13(6):617-24.
12. Gonzalez-Perez LM, Infante-Cossio P, Granados-Nuñez M, Urresti-Lopez FJ. Treatment of temporomandibular myofascial pain with deep dry needling. Med Oral Patol Oral Cir Bucal. 2012;17(5):e781-5.
13. Kalichman L, Vulfsons S. Dry needling in the management of musculoskeletal pain. J Am Board Fam Med. 23(5):640-6.
14. Macdonald AJ, Macrae KD, Master BR, Rubin AP. Superficial acupuncture in the relief of chronic low back pain. Ann R Coll Surg Engl. 1983;65(1):44-6.
15. Näslund J, Näslund UB, Odenbring S, Lundeberg T. Sensory stimulation (acupuncture) for the treatment of idiopathic anterior knee pain. J Rehabil Med. 2002;34(5):231-8.