Myofascial Trigger Points: An Evidence-Informed Review

The literature on psychological factors in neck and back pain was systematically searched and reviewed. To summarize current knowledge concerning the role of psychological variables in the etiology and development of neck and back pain. Recent conceptions of spinal pain, especially chronic back pain, have highlighted the role of psychological factors. Numerous studies subsequently have examined the effects of various psychological factors in neck and back pain. There is a need to review this material to ascertain what conclusions may be drawn. Medical and psychological databases and cross-referencing were used to locate 913 potentially relevant articles. A table of 37 studies was constructed, consisting only of studies with prospective designs to ensure quality. Each study was reviewed for the population studied, the psychological predictor variables, and the outcome. The available literature indicated a clear link between psychological variables and neck and back pain. The prospective studies indicated that psychological variables were related to the onset of pain, and to acute, subacute, and chronic pain. Stress, distress, or anxiety as well as mood and emotions, cognitive functioning, and pain behavior all were found to be significant factors. Personality factors produced mixed results. Although the level of evidence was low, abuse also was found to be a potentially significant factor. Psychological factors play a significant role not only in chronic pain, but also in the etiology of acute pain, particularly in the transition to chronic problems. Specific types of psychological variables emerge and may be important in distinct developmental time frames, also implying that assessment and intervention need to reflect these variables. Still, psychological factors account for only a portion of the variance, thereby highlighting the multidimensional view. Because the methodologic quality of the studies varied considerably, future research should focus on improving quality and addressing new questions such as the mechanism, the developmental time factor, and the relevance that these risk factors have for intervention.

This article explores how myofascial trigger points (MTrPs) may relate to musculoskeletal dysfunction (MSD) in the workplace and what might be done about it. The cause of much MSD and pain is often enigmatic to modern medicine and very costly, just as the cause of MTrPs has been elusive for the past century, despite an extensive literature that is confusing because of restricted regional approaches and a seemingly endless variety of names. MTrPs are activated by acute or persistent muscle overload, which is characteristic of MSD in the workplace. MTrPs can involve any, and sometimes many, of the skeletal muscles in the body and are a major, complex cause of musculoskeletal pain. The clinical and etiological characteristics of MTrPs have been underexplored by investigators, leading to undertraining of health care professionals, underappreciation of their clinical importance. MTrPs have no gold standard diagnostic criterion, and no routinely available laboratory or imaging test. MTrPs require a specific non-routine examination and muscle-specific treatment for prompt relief when acute, and also resolution of perpetuating factors when chronic. After identifying a critical false assumption, electrodiagnostic studies are now making encouraging progress toward clarifying the etiology of MTrPs based on the 5- or 6-step positive-feedback model of the integrated hypothesis. Specific research needs are noted. MTrPs are treatable and they deserve increased attention and consideration by research investigators and clinicians.

The concentration of plasma interleukin-6 (IL-6) increases during physical exercise, but until recently the cellular origin of this increase has been unknown. Recent work has identified that skeletal muscle is a major source of this increase and the release of IL-6 from muscle can mediate metabolic processes. IL-6 is, therefore, the first identified "myokine" released from muscle that can now be termed an endocrine organ.