A previous review, which appeared on these same pages, was dedicated to the different alternative techniques to local anaesthesia conventionally used in dentistry, and reference was made to myofascial syndrome as one of the possible indications for the use of electronic dental anaesthesia (EDA), a method based on the technique of transcutaneous electrical nerve stimulation (TENS).
The myofascial pain syndrome has considerable weight on the population; in 2016, in the United States, it had an estimated prevalence of 13.8%. It is certainly an orthopaedic pathology that, however, also receives great interest from oral medicine and, in particular, from gnathology.
This is a complex disorder characterized by persistent musculoskeletal pain that, most of the time, affects the head and neck region early. The deep painful symptom originates from “tender spots” located in variable areas of the muscles called “trigger points.” The duplication of pain, following palpatory stimulation of a trigger point, is an essential diagnostic element.
Because of its complexity, an aetiology that has not been completely clarified along with its numerous different risk factors, the therapeutic approach is articulated in a multidisciplinary manner. Intervention procedures include postural correction, muscle exercise, biofeedback, topical or local drugs, as well as intraoral devices and TENS.
From a pharmacological point of view, injections at the level of the trigger points themselves are one of the most effective options. These involve the administration of different compounds, which are not all properly pharmacological, such as local anaesthetics, steroids, botulinum toxin, saline solution, and even include techniques “dry.” The use of local anaesthetics, lidocaine above all, has been used since 1938 and is now commonly referred to as a second line after the failure of one of the non-invasive therapies listed above.
Nouged and colleagues have conducted a systematic review of the literature published in the Journal of Oral & Facial Pain and Headache with the aim of comparing the effectiveness of different injection techniques.
Starting from a total of 324 reports from the PubMed, Web of Science, and EMBASE databases, 15 randomized clinical trials were brought to final evaluation, referring to a sample of 884 adult subjects with the myofascial syndrome. The meta-analysis conducted on 11 studies showed an improvement in the painful symptom (primary outcome, measured on a visual-analogical VAS scale) at 4 weeks with significantly higher local anaesthetic and, within 2-8 weeks, at placebo. Despite the long expertise in applicability and safety, however, the authors believe to suggest the implementation of new, more rigorous study protocols (RCT double-blind) in order to better define the modalities of application.