Myofascial syndrome is defined as a pain disorder involving pain referred from trigger points within myofascial structures, either local or distant to the pain. This article discusses the clinical features, pathogenesis, differential diagnosis, and management of myofascial pain disorder. Starting with the classical work of Travell in the 1980s, this article goes on to describe some of the more recent efforts to manage this syndrome.
| || |
• Active trigger points are characterized by specific patterns of pain radiation during palpation that depend on the location of the trigger point.
| || |
• Patients who respond to treatment in the acute phase usually have a good prognosis, but chronic nonresponsive patients are a problem in management.
| || |
• Myofascial pain syndrome should be differentiated from other painful conditions involving muscles, such as fibrositis.
| || |
• Noninvasive techniques of management include counterpoint stimulation, spray and stretch, massage, Kinesio taping, and topical medication patches.
| || |
• Various modalities of electrical stimulation include transcutaneous electrical stimulation, pulsed electric neuromuscular stimulation, and pulsed radiofrequency.
| || |
• Injections into myofascial trigger points are usually local anesthetics, but botulinum toxin has also been used.
Historical note and terminology
It has been nearly a century since Sir William Gowers introduced the term fibrositis for a common, but idiopathic, localized form of muscular rheumatism that is now recognized as myofascial pain syndrome (20).
According to Gowers in 1904, the term “fibrositis” referred to the local tenderness and regions of palpable hardness in the muscle, which he attributed to inflammation of fibrous tissue. Though initially embraced in the literature, the concept of fibrositis as inflamed connective tissue fell into disfavor as subsequent biopsy data failed to substantiate inflammatory pathology. It was not until the late 1930s that Kellgren provided evidence for the pathomechanism and nature of pain originating from deep connective tissue structures (27). Using hypertonic saline injections to irritate different anatomical areas including fascia, tendon, and muscle, he demonstrated that pain was produced that differed not only in quality but also in its specific referral pattern. Although the term "myofasciitis" was first introduced in 1927 by Albee, it was not until 1939 that Steindler first used the terms "myofascial pain" and "trigger point" (02; 56). Travell and colleagues used the term trigger point in 1942 to describe the site from which pain was referred, and in 1952, adopted the expression "myofascial pain syndrome" (61; 60). In 1954, Schwartz reported that inactivation of trigger points by procaine injection was often an important part of the management of pain in the temporomandibular joint region (46). According to Travell, it was Good who recognized the pathognomonic trademark of myofascial pain syndrome, now called the “jump sign,” where a patient responded with a cry, grimace, or wince to palpation of the painful muscle focus (62).
Travell first published a paper describing the diagnostic criteria and treatment protocols for myofascial pain syndrome in 1942, which laid the foundation for the modern approach to this syndrome. In 1953, Bonica published a text separating myofascial pain syndrome from fibrositis (08). The subsequent work of Travell and Simons elucidated trigger points and zones of radiating pain, as well as the taut bands of myofascial pain syndrome, codifying their locations in virtually every muscle of the body (62; 63). Using the classification of the International Association for the Study of Pain, such localized disease was termed "specific myofascial pain syndrome" (39). Specific terms are being used to describe involvement of certain anatomical regions, eg, myofascial pain dysfunction syndrome in case of temperomandibular joint.
Controversies in nomenclature. A source of controversy relative to the acceptance of the concepts of myofascial pain and dysfunction has been the varied terminology used throughout the literature. The term “fibrositis” has been used erroneously to include both myofascial pain syndrome and fibromyalgia, as well as almost any unexplained musculoskeletal pain problem. Other terms used in the past include “myogelosis,” “muscle hardening,” and “muscular rheumatism.” The confusion in nomenclature has been compounded by the widespread belief that these musculoskeletal pain syndromes are psychogenic in nature. As late as the 1970s, most major textbooks considered fibrositis to be a disease with strong psychogenic overtones (45). The terms nonarticular and psychogenic rheumatism, soft tissue disability, tension myalgia, and muscle contraction states also have remained in use, suggesting psychologic dysfunction as their primary cause as opposed to physical factors. Similarly, current terms, including overuse syndromes, repetitive trauma syndromes, and repetitive injury or strain syndromes fail to address the more critical issues regarding pathogenesis, with many of these overlapping disorders representing local forms of myofascial pain, which apparently have not been appreciated as such. Currently, no universally accepted terminology enables clinicians to more accurately codify the dysfunction seen in patients who present with musculoskeletal pain and dysfunction.