3. Discussion
myofascial pain, myalgia, temporomandibular disorders, MM, PNE, pain, Temporo-Mandibular Disorders, masticatory muscle pain, craniofacial pain, bruising, mandibular movements, masticatory muscle function
TEMPOROMANDIBULAR DISORDERS, MYOFASCIAL PAIN, TEMPOROMANDIBULAR DISORDERS, ADVERSE EFFECTS, INFILTRATING
In this randomized clinical trial, we aimed to evaluate the use of BTA and PNE in a group of patients with chronic MM, who were similar in terms of mean age, gender distribution, pain patterns, range of mandibular movements, and electromyographic recordings. When comparing the two therapeutic tools with each other, neither showed significant superiority over the other in any of the variables nor in the efficacy and tolerance of the patient and the observer. However, four cases of mild side effects were detected in the PNE group, which did not prevent the study from being carried out. In general, our findings revealed that statistically significant positive therapeutic responses were obtained in each group. Compared to pre-treatment baseline values, both BTA and PNE were effective procedures that significantly improved pain and masticatory muscle function. The results were significant in the first month, although improvement in the different variables was maintained during the three months of the study in each group. Chronic MM is a debilitating health condition and one of the leading causes of consultation in craniofacial pain [In 2014, some diagnostic categories in the RDC/TMD (Research Diagnostic Criteria for Temporomandibular Disorders) were eliminated, while others such as localized myalgia were included. In the new DC/TMD classification (Diagnostic Criteria for Temporo-Mandibular Disorders for Clinical and Research Applications) [We designed a randomized controlled study comparing two minimally invasive emergent interventions. As in previous studies, an adequate sample size of 26 subjects per group was calculated [Although BTA is an effective treatment for masticatory muscle pain, few studies uniformly support it in the orofacial area, undoubtedly due to the heterogeneity of the samples studied to date [The efficacy of myofascial pain relief following BTA injection has not yet been established in the literature. We believe that one of the main reasons for this controversy is related to the wide disparity in the inclusion and exclusion criteria used in the reviewed studies [In addition, it is important to highlight that the EMG recording we performed before treatment and the use of specific needle electrodes for BTA injections are useful and necessary procedures to identify the muscle masses to be treated and to avoid administration errors and side effects. In our literature review, we also found significant variation in the doses of BTA used and the muscles injected [Finally, our patients were evaluated taking into account the contraindications of treatments. The efficacy and tolerability were the same in both groups as estimated by the patient and the observer. As with any minimally invasive technique, both BTA and PNE were well tolerated, with no significant contraindications. No side effects were detected with BTA, while four cases of self-limited pain and bruising at the puncture site were reported in the PNE group. In our experience, it is useful and convenient to localize the affected muscles by EMG, so in this study we used needle electrodes that allow BTA injection at the same time. Multipoint injection achieves more uniform contact between BTA and the innervated muscle areas, which is especially advantageous when infiltrating larger muscles. It is important to bear in mind that local diffusion of BTA may depend on the volume and dose administered and that large volumes may impair the integrity of the muscle fascia, so this is another aspect we have taken into account to minimize side effects in our study. It is generally accepted that low doses of botulinum toxin should be administered to limit the associated adverse effects [Our study had some limitations, such as the inconvenience of blinding the study subjects, which limits the validity of the measurement of the results obtained. Although three months of follow-up is an adequate time to evaluate the results, studies that consider longer evaluation periods should be conducted. The effect of psychosocial variables on temporomandibular disorders should also be considered, as they may act as factors in the chronification of pain [