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Myofascial pain syndrome (MPS) is an extremely common condition that affects millions of Americans, yet it often goes unrecognized or is mistaken for other problems. The article notes that approximately 44 million US residents are affected, with prevalence estimates reaching 37% among men and 65% among women between ages 30 and 60, and climbing to 85% in older adults. The hallmark of MPS is the myofascial trigger point (MTrP) — a hypersensitive, palpable knot in muscle that causes pain locally and can refer pain to other areas. These trigger points can be active (causing noticeable symptoms) or latent (only detected on examination).

Despite how common MPS is, there are no standardized diagnostic criteria, and the condition overlaps with many other musculoskeletal disorders, leading to frequent underdiagnosis or misdiagnosis. This is particularly problematic because pain accounts for nearly 78% of emergency department visits, and it is unknown how many of these are due to unrecognized MPS.

This article is a narrative review aimed at educating primary care nurse practitioners (NPs) about MPS and its treatment, with special emphasis on trigger point injection (TPI) technique. The author synthesized existing literature on MPS pathophysiology, diagnosis, and treatment options. The review covers how to take a focused history, perform a physical examination using three palpation techniques (flat, pincer, and deep palpation), and distinguish MPS from conditions like fibromyalgia, arthritis, and nerve entrapment. The article then surveys noninvasive treatments including stretching, NSAIDs, antidepressants, antiepileptics, muscle relaxants, and physical modalities, as well as invasive options like dry needling and acupuncture.

The core of the article provides a detailed, step-by-step guide to performing TPIs in outpatient practice, including patient positioning, equipment selection, injection technique, postprocedure care, and billing codes.

The review highlights several key evidence-based findings from the literature it surveys. Trigger point injections with lidocaine were found superior to IV NSAIDs for lumbar myofascial pain in one emergency department study. Botulinum toxin A showed superior pain relief and improved function in more than half of participants with chronic low back pain at 8 weeks, though benefits waned after 3 to 4 months. However, a large 2014 review concluded that evidence for botulinum toxin A in MPS remains inconclusive due to conflicting data across studies.

Critically, normal saline TPI showed similar efficacy to conventional active drug mixtures (lidocaine with steroid) both immediately after injection and at 2-week follow-up, and botulinum toxin A was not superior to normal saline for cervical and shoulder MPS. Several studies suggest that no single injectate has clear advantages, implying that much of TPI benefit comes from the mechanical needle effect itself. Dry needling was found more effective than no treatment or sham at 12 weeks in a 2017 systematic review and meta-analysis. The article also notes troubling diagnostic reliability issues: interexaminer agreement on MTrP location was only 21% in one study, and providers mislocated upper trapezius trigger points by an average of 3.3 to 3.6 cm.

For primary care NPs, this review offers practical guidance for bringing TPI capability into outpatient practice without requiring specialty referral. The key clinical implication is that TPI with normal saline or lidocaine represents a low-cost, low-risk intervention that can provide meaningful relief, particularly when integrated into a multimodal approach including stretching and physical therapy. The finding that normal saline works as well as more complex injectates is especially important for resource-limited settings. However, the poor interexaminer reliability in locating trigger points underscores the critical need for additional training and standardized education.

Patients with MPS may benefit from knowing that their condition is common and treatable, that multiple options exist beyond medication, and that NPs with proper training can offer in-office procedures that may reduce pain enough to allow participation in rehabilitative exercises. The absence of clinical guidelines means treatment must be individualized through shared decision-making, but TPI remains the most established invasive option for persistent trigger points.