There is no consensus on the essential diagnostic criteria for diagnosing a trigger point (TrP). In fact, a variety of diagnostic criteria are currently being used. Our aim was to conduct a Delphi panel to achieve an international consensus on the cluster of criteria needed for the TrP diagnosis to reach a consensus on the definition of active and latent TrPs and to clarify different clinical considerations about TrPs. Following international guidelines, an international three-round Delphi survey was conducted. Questions were created based on a systematic literature search of the diagnostic criteria for TrPs. Sixty experts from 12 countries completed all rounds of the survey. A cluster of three diagnostic criteria was proposed as essential for the TrP diagnosis: a taut band, a hypersensitive spot, and referred pain. Eighty percent of the experts agreed that the referred pain elicited by a TrP can include different sensory sensations and not just pain, that is, pain spreading to a distant area, deep pain, dull ache, tingling, or burning pain. Eighty-four percent of the international experts consistently answered that the main clinical differences between active and latent TrPs are the reproduction of any of the symptoms experienced by a patient and the recognition of pain. No specific location of the pain referral area and TrP location should be expected. This Delphi panel has produced an expert-based standardized definition of a TrP with a discussion of the clinical components, including the definition of referred pain and the difference between active and latent TrPs, thereby providing a foundation for future research in MPS.

Myofascial pain syndrome (MPS) is described as the sensory, motor, and autonomic symptoms caused by myofascial trigger points (TrPs). Knowing the potential causes of TrPs is important to prevent their development and recurrence, but also to inactivate and eliminate existing TrPs. There is general agreement that muscle overuse or direct trauma to the muscle can lead to the development of TrPs. Muscle overload is hypothesized to be the result of sustained or repetitive low-level muscle contractions, eccentric muscle contractions, and maximal or submaximal concentric muscle contractions. TrPs may develop during occupational, recreational, or sports activities when muscle use exceeds muscle capacity and normal recovery is disturbed.

Dry needling is a common treatment technique in orthopedic manual physical therapy. Although various dry needling approaches exist, the more common and best supported approach targets myofascial trigger points. This article aims to place trigger point dry needling within the context of pain sciences. From a pain science perspective, trigger points are constant sources of peripheral nociceptive input leading to peripheral and central sensitization. Dry needling cannot only reverse some aspects of central sensitization, it reduces local and referred pain, improves range of motion and muscle activation pattern, and alters the chemical environment of trigger points. Trigger point dry needling should be based on a thorough understanding of the scientific background of trigger points, the differences and similarities between active and latent trigger points, motor adaptation, and central sensitize application. Several outcome studies are included, as well as comments on dry needling and acupuncture.

Trigger point dry needling (TrP-DN) is commonly used to treat persons with myofascial pain, but no studies currently exist investigating its safety. The aim of this study was to determine the incidence of Adverse Events (AEs) associated with the use of TrP-DN by a sample of physiotherapists in Ireland. A prospective survey was undertaken consisting of two forms recording mild and significant AEs. Physiotherapists who had completed TrP-DN training with the David G Simons Academy (DGSA) were eligible to take part in the study. Data were collected over a ten-month period. In the study, 39 physiotherapists participated and 1463 (19.18%) mild AEs were reported in 7629 treatments with TrP-DN. No significant AEs were reported giving an estimated upper risk rate for significant AEs of less than or equal to (≤) 0.04%. Common AEs included bruising (7.55%), bleeding (4.65%), pain during treatment (3.01%), and pain after treatment (2.19%). Uncommon AEs were aggravation of symptoms (0.88%), drowsiness (0.26%), headache (0.14%), and nausea (0.13%). Rare AEs were fatigue (0.04%), altered emotions (0.04%), shaking, itching, claustrophobia, and numbness, all 0.01%. While mild AEs were very commonly reported in this study of TrP-DN, no significant AEs occurred. For the physiotherapists surveyed, TrP-DN appeared to be a safe treatment.