Evaluation of the Therapeutic Use of Local Anesthetics in Chronic Myogenous Temporomandibular Disorders: A Pilot Study and Evidence Gap Assessment

Background/Objectives: The therapeutic use of local anesthetics has been discussed in several musculoskeletal pain conditions, but its role in myogenous temporomandibular disorders (TMDs) remains unclear. This study evaluated clinical outcomes after a therapeutic local anesthetic injection protocol in patients with chronic myogenous TMDs and examined whether comparable clinical evidence exists in the literature. Methods: This retrospective study included patients diagnosed with myalgia according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) criteria. Patients received six weekly sessions of therapeutic local anesthetic injections targeting trigeminal nerve exit points, myofascial trigger points in the masticatory and cervical muscles, the projection area of the otic ganglion, and upper cervical segments. Mandibular mobility, pain intensity, and DC/TMD Axis II measures were compared between baseline and 3-month follow-up. A structured literature search was also performed in PubMed, Cochrane Library, LIVIVO, Ovid MEDLINE, Scopus, and Web of Science. Results: Twenty-seven patients were included. Pain-free mouth opening, maximum unassisted mouth opening, and maximum assisted mouth opening increased after therapy. Pain intensity and patient-reported measures of jaw function, depressive and anxiety symptom scores, somatic symptom scores, and oral behavior scores decreased. The literature search identified 1406 records; after duplicate removal, 561 records were screened. Several studies investigating local injections for TMDs were identified; however, none appeared to evaluate the specific injection protocol used in this cohort. Conclusions: Therapeutic local anesthetic injections were associated with improvements in pain, jaw function, and patient-reported outcomes in this retrospective pilot cohort. Owing to the lack of a control group, the findings should be interpreted with caution.