Dry needling in the management of myofascial trigger points: A systematic review of randomized controlled trials
Introduction
Myofascial Trigger Points (MTrPs) are “hyperirritable points in skeletal muscle that are associated with a hypersensitive palpable nodule in a taut band”.1 It is estimated that MTrPs are the primary cause of pain in 30–85% of those with musculoskeletal disorders.2, 3, 4 The MTrPs seem to be associated with histological (shortening of involved sarcomeres and tissue hypoxia) 5 and biochemical (excessive release of acetylcholine, lowered pH and excessive release of P substance) 6, 7 changes, which influence the process of sensitization of the central and peripheral nervous system.6, 8
Myofascial pain syndrome is a regional muscular pain condition characterized by MTrPs found in one or more muscles and/or connective tissues.9 It can be associated with pain, muscle spasm, increased sensitivity, stiffness, muscle weakness, decreased range of motion and autonomic dysfunction.9 The mechanical stimulation of MTrPs can cause local and referred pain, motor dysfunction and autonomic phenomena.9, 10 Despite the clinical acceptance of MTrPs, its role as a relevant clinical entity in the pathogenesis of myofascial pain syndrome is still controversial.11
MTrPs and myofascial pain syndrome have been treated with several therapeutic modalities, including therapeutic ultrasound,12, 11 ischemic compression techniques,12, 13 muscle energy techniques,13 stretching,13 manipulation,14 acupuncture 4[4] and dry needling.15 During the last decade, evidence on the role of dry needling of MTrPs in the management of several musculoskeletal disorders has been increasing, including plantar heel pain,16 temporomandibular disorders,17, 18 epicondylalgia 19 or myofascial pain syndrome.20 Dry needling consists of using a needle, as a physical agent, to create a mechanical stimulus with the goal of deactivating the trigger point.21 It is an invasive procedure, where the needle is inserted through the skin and muscle into the MTrP.15 Once the MTrP is deactivated, the needle is removed.22 It is cheap, easy to learn and with low risks associated.23 Despite being a technique commonly used by health professionals, its clinical effectiveness is not clear. A recent systematic review on the effectiveness of dry needling has focused on MTrPs associated with the neck and shoulder regions.23 The authors concluded that dry needling can be recommended for relieving MTrP pain in neck and shoulders.23 We aim to expand this review by adding studies on other anatomical regions, and exploring whether differences in the application of dry needling, such as the characteristics of the needle, the number of times that the needle was inserted into the MTrPs and the number of treatment sessions, can impact on its effectiveness. Thus, the aim of this study was to undertake a systematic review to examine the effectiveness of dry needling in the treatment of MTrPs and to explore the impact of specific aspects of the technique on its effectiveness.
Section snippets
Databases and search strategy
A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.24
Relevant studies published between 2000 and 2015 were identified by searching PubMed, Scopus, The Cochrane Library and Physiotherapy Evidence Database (PEDro). The search terms were the following: “dry needling”, “trigger point”, “myofascial trigger point”, “myofascial pain syndrome”, combined as follows: (i) [trigger point* OR myofascial trigger point* OR myofascial
Study selection
From the web-based search, 90 articles were identified. Of these, 30 articles were duplicates and, therefore, were excluded. Of the 60 potentially eligible articles, 45 were discarded due to the following reasons: did not comprise a dry needling intervention (n = 30), did not apply the criteria described by Travell and Simons (n = 2) to define MTrP, used a single blinded within-subject design (n = 1), pain intensity was not an outcome measure (n = 1), review paper (n = 6), book chapter, comment or
Discussion
This systematic review aimed to examine the effectiveness of dry needling in the treatment of MTrPs and to explore the impact of specific aspects of the technique on its effectiveness. Fifteen RCTs that compared dry needling with sham/placebo intervention, no intervention or other interventions were identified and included in this systematic review. Results suggest that dry needling is effective for pain relief in the short term when compared to sham/placebo needling or no intervention.
Conclusions
Despite some evidence that dry needling can have a positive effect in the short term on pain, range of motion and quality of life when compared to sham/placebo/no intervention, and similar effects to pharmacological interventions, further randomized clinical trials of high methodological quality, using standardized procedures for dry needling application are needed.
Conflict of interest statement
None declared
Acknowledgements
iBiMED is a research unit supported by the Portuguese Foundation for Science and Technology (REF: UID/BIM/04501/2013) and FEDER/Compete2020 funds.
CINTESIS is supported by FEDER through the operation POCI-01-0145-FEDER-007746 funded by the Programa Operacional Competitividade e Internacionalização - COMPETE2020 and by National Funds through FCT − Fundação para a Ciência e a Tecnologia (reference UID/IC/4255/2013)
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