Pain Management: Trigger Point Injection

Pain Management: Trigger Point Injection

Trigger points, also known as trigger sites or muscle knots, are described as hyperirritable spots in skeletal muscle that are associated with palpable nodules in taut bands of muscle fibers. Trigger point practitioners believe that palpable nodules are small contraction knots and a common cause of pain. Compression of a trigger point may elicit local tenderness, referred pain, or local twitch response. The local twitch response is not the same as a muscle spasm. This is because a muscle spasm refers to the entire muscle contracting whereas the local twitch response also refers to the entire muscle but only involves a small twitch, no contraction. The trigger point model states that unexplained pain frequently radiates from these points of local tenderness to broader areas, sometimes distant from the trigger point itself.

Practitioners claim to have identified reliable referred pain patterns, allowing practitioners to associate pain in one location with trigger points elsewhere. Many practitioners of chiropractic and massage therapy find the model useful, but the medical community at large has not embraced trigger point therapy. There is no consistent methodology for diagnosis of trigger points and a dearth of theory to explain how they arise and why they produce specific patterns of referred pain Trigger points are discrete, focal, hyperirritable spots located in a taut band of skeletal muscle. They produce pain locally and in a referred pattern and often accompany chronic musculoskeletal disorders. Acute trauma or repetitive micro trauma may lead to the development of stress on muscle fibers and the formation of trigger points. Patients may have regional, persistent pain resulting in a decreased range of motion in the affected muscles. These include muscles used to maintain body posture, such as those in the neck, shoulders, and pelvic girdle. Trigger points may also manifest as tension headache, tinnitus, temporomandibular joint pain, decreased range of motion in the legs, and low back pain. Palpation of a hypersensitive bundle or nodule of muscle fiber of harder than normal consistency is the physical finding typically associated with a trigger point. Palpation of the trigger point will elicit pain directly over the affected area and/or cause radiation of pain toward a zone of reference and a local twitch response. Various modalities, such as the Spray and Stretch technique, ultrasonography, manipulative therapy and injection, are used to inactivate trigger points. Trigger-point injection has been shown to be one of the most effective treatment modalities to inactivate trigger points and provide prompt relief of symptoms.
About 23 million persons, or 10 percent of the U.S. population, have one or more chronic disorders of the musculoskeletal system.
•     Musculoskeletal disorders are the main cause of disability in the working-age population and are among the leading causes of disability in other age groups.
•     Myofascial pain syndrome is a common painful muscle disorder caused by myofascial trigger points.
•     This must be differentiated from fibromyalgia syndrome, which involves multiple tender spots or tender points. These pain syndromes are often concomitant and may interact with one another.
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