Myofascial Pain Syndrome: A Narrative Review Identifying Inconsistencies in Nomenclature.

There is currently confusion surrounding the phenotype of and diagnostic criteria for myofascial pain syndrome (MPS) in the published literature. This narrative literature review investigated whether there is consensus regarding the descriptive terminology used for MPS and the trend of MPS publications over time. The phrase "myofascial pain syndrome" was used to search PubMed and Web of Science, returning 923 articles. Of these, we included only full-text, primary research articles containing "myofascial pain syndrome" in the title, reducing the total articles reviewed to 167. We identified 116 descriptors and categorized them under one of five clusters that shared similar findings and are commonly associated with MPS: "trigger points," "muscle," "pain," "nervous system," and "fascia." The frequency of the clinical criteria of Travell and Simons was tabulated. Terms pertaining to the clusters "trigger points," "muscle," or "pain" appeared in approximately 90% of the articles; "nervous system" in 46%; and "fascia" in 20%. Only 42% used the criteria of Travell and Simons. Most articles (122) included a combination of three or four clusters to describe MPS. In addition, MPS publications have doubled since 2010 compared to the prior decade. The publication patterns, determined by changes in which specialty journals articles on MPS have been published, have shifted from investigational to intervention studies. This may have been influenced by heterogeneity in the usage of MPS terminology. This underscores the lack of a reliable MPS diagnosis and limits human subjects research. Improved consistency in terminology is needed to establish consensus within the field and to inform future research studying the pathophysiology of MPS.