Trigger Point Injections

Myofascial trigger points (MTrPs) are defined as the tender (hyperirritable) foci in a palpable taut band of skeletal muscle fibers that can elicit pain, referred pain, a local twitch response (LTR), motor dysfunction, as well as autonomic phenomena, among other symptoms. The pathophysiology of trigger points can be explained by the integrated hypothesis which has three essential features including excessive acetylcholine release, sarcomere shortening, and the release of sensitizing substances. Diagnosis of trigger points is best done with a proper history and physical exam in which tender points and/or patterns of referred pain are elicited that does not follow any dermatomal or myotomal pattern. Trigger point injections are specific techniques aimed at the alleviation of pain located within the MTrP and can be performed by injecting an agent into the MTrP or through dry needling causing the relaxation and lengthening of the involved muscle fibers. Even though trigger point injections are regarded as safe procedures, like all procedures, appropriate precautions must be taken into consideration. Correction of mechanical or structural stressor is required to prevent recurrence.