Myofascial Trigger Points Then and Now: A Historical and Scientific Perspective.

The intent of this article is to discuss the evolving role of the myofascial trigger point (MTrP) in myofascial pain syndrome (MPS) from both a historical and scientific perspective. MTrPs are hard, discrete, palpable nodules in a taut band of skeletal muscle that may be spontaneously painful (i.e., active) or painful only on compression (i.e., latent). MPS is a term used to describe a pain condition that can be acute or, more commonly, chronic and involves the muscle and its surrounding connective tissue (e.g. fascia). According to Travell and Simons, MTrPs are central to the syndrome-but are they necessary? Although the clinical study of muscle pain and MTrPs has proliferated over the past two centuries, the scientific literature often seems disjointed and confusing. Unfortunately, much of the terminology, theories, concepts, and diagnostic criteria are inconsistent, incomplete, or controversial. To address these deficiencies, investigators have recently applied clinical, imaging (of skeletal muscle and brain), and biochemical analyses to systematically and objectively study the MTrP and its role in MPS. Data suggest that the soft tissue milieu around the MTrP, neurogenic inflammation, sensitization, and limbic system dysfunction may all play a role in the initiation, amplification, and perpetuation of MPS. The authors chronicle the advances that have led to the current understanding of MTrP pathophysiology and its relationship to MPS, and review the contributions of clinicians and researchers who have influenced and expanded our contemporary level of clinical knowledge and practice.

Dry Needling Alters Trigger Points in the Upper Trapezius Muscle and Reduces Pain in Subjects With Chronic Myofascial Pain.

OBJECTIVE: To determine whether dry needling of an active myofascial trigger point (MTrP) reduces pain and alters the status of the trigger point to either a non-spontaneously tender nodule or its resolution. DESIGN: A prospective, nonrandomized, controlled, interventional clinical study. SETTING: University campus. PARTICIPANTS: A total of 56 subjects with neck or shoulder girdle pain of more than 3 months duration and active MTrPs were recruited from a campus-wide volunteer sample. Of these, 52 completed the study (23 male and 33 female). Their mean age was 35.8 years. INTERVENTIONS: Three weekly dry needling treatments of a single active MTrP. PRIMARY OUTCOMES: Baseline and posttreatment evaluations of pain using a verbal analogue scale, the Brief Pain Inventory, and the status of the MTrP as determined by digital palpation. Trigger points were rated as active (spontaneously painful), latent (requiring palpation to reproduce the characteristic pain), or resolved (no palpable nodule). SECONDARY OUTCOMES: Profile of Mood States, Oswestry Disability Index, and Short Form 36 scores, and cervical range of motion. PRIMARY OUTCOMES: A total of 41 subjects had a change in trigger point status from active to latent or resolved, and 11 subjects had no change (P < .001). Reduction in all pain scores was significant (P < .001). SECONDARY OUTCOMES: Significant improvement in posttreatment cervical rotational asymmetry in subjects as follows: unilateral/bilateral MTrPs (P = .001 and P = 21, respectively); in pain pressure threshold in subjects with unilateral/bilateral MTrPs, (P = .006 and P = .012, respectively); improvement in the SF-36 mental health and physical functioning subscale scores (P = .019 and P = .03), respectively; and a decrease in the Oswestry Disability Index score (P = .003). CONCLUSIONS: Dry needling reduces pain and changes MTrP status. Change in trigger point status is associated with a statistically and clinically significant reduction in pain. Reduction of pain is associated with improved mood, function, and level of disability.