Discussion
This overview summarized data and key results from five systematic reviews that investigated the effects of different DDwoR treatments and assessed the quality of evidence from these reviews. The analysis of general data revealed heterogeneity between studies. Despite the significant number of primary studies on the subject, the significant variation in pairwise comparisons within each study compromises evidence-based clinical/surgical decision-making for the treatment of DDwoR. Different outcome evaluation criteria and follow-up times were also observed. These characteristics also compromised the grouping of studies for meta-analyses in systematic reviews.
Among the reviews that performed meta-analyses,7-10,12one included only one RCT9 and three included two to four RCTs.8,10,12 In a third systematic review, 15 studies were considered in the meta-analysis,7 based on indirect comparisons, including comparison between prospective uncontrolled studies and RCTs. These authors constructed a different artificial, untreated control group, which represents a bias and compromises the degree of confidence of the results, since the comparative analyzes were not based on real samples and did not consider eligibility criteria, random allocation, collection and blind analysis of the data.
Despite the number of primary studies on the subject, this overview revealed a significant variation in comparisons related to the treatment of DDwoR in RCTs. Comparison between different non-invasive modalities,8-10 non-invasive versus minimally invasive,10,12 non-invasive versus invasive,8-10 minimally invasive versus invasive7,10 and comparison between invasive modalities7-10 were observed.
The systematic reviews included primarily compared the effects of non-invasive treatments for DDwoR. This can be explained by the fact that this modality is considered, by consensus, as the first therapeutic option for DDwoR. In addition, the significant number of non-invasive options applied alone or in combination in the treatment of DDwoR also contributes to a greater number of publications and favors the carrying out of secondary studies on the subject.
The signs and symptoms associated with DI are caused by the loss of intra-articular tissue structure and function, compromising the biomechanics of the biomechanical temporomandibular joint. The cause of this tissue failure is most often joint overload, leading to tissue failure and an inflammatory/degenerative arthropathy of the temporomandibular joint.20
It is not possible to state which is the best non-invasive treatment method, as in most reported results no significant difference was detected in pain control and improvement in MMO between groups. This finding may be related to the self-limited natural course of DDwoR. Significant improvement in clinical symptoms of closed lock is expected in 75 % of patients over a 2.5-year follow-up. The reduction in pain and mouth opening restriction is probably associated with the active adaptation to the new structural situation of the TMJ.20,21 Even so, the therapeutic approach to DDwoR is necessary due to the expected benefits of pain and functional limitations, in addition to preventing osteoarthritis as an evolution of the internal TMJ disorder. The persistence of these clinical symptoms and the evolution of joint TMD lead to the need for TMJ invasive therapeutic approaches.
In this context, the minimally invasive modalities, represented by arthrocentesis, represent the first step in the treatment of ID, after the failure of the non-invasive approach. This technique had mild and pain-restricted benefits, only in the short term, compared to the non-invasive combined treatment. Despite limitations for clinical decision-making associated with heterogeneity between studies, the data summarized in this overview suggest a small benefit of arthrocentesis in the treatment of DDwoR, restricted to clinical symptoms and only in the short term, compared to non-invasive therapeutic modalities.
Arthroscopic surgery and arthroplasty did not show significant differences in pain control and MMO compared to non-invasive modalities,8-10 and arthrocentesis and arthroscopy did not differ for improvement assessed by the patient, pain reduction and MMO.7,10 Open surgery showed short-term improvement in pain control compared to non-invasive treatment, significant overall improvement and long-term improvement in pain intensity, compared to arthroscopy.10
The optimal treatment for DDwoR should not be considered universal protocol, but a personalized approach. Each patient must be assessed and treated individually considering the severity of symptoms and functional limitations associated with TMD, prioritizing the non-invasive treatment model, followed by minimally invasive and invasive/open surgery modalities. Bronstein and Merrill21 reported higher success rates for arthroscopic treatment of ID in early stages than in advanced stages. Zhang et al.22 reported that arthroscopic disc repositioning was not appropriate for Wilkes stage IV or V, suggesting a limitation of the technique for more complex cases.
Successive treatment attempts by different therapeutic modalities, in a gradual hierarchical sequence of complexity/invasiveness, should represent delay in the remission of clinical signs and symptoms of TMD associated with DDwoR and greater morbidity in more complex/severe cases. However, invasive procedures, such as open surgery, must be carefully indicated considering the possible pitfalls.23
Despite the limitations of this study and the impossibility of establishing the most effective evidence-based treatment for DDwoR, all treatments benefit patients and had slightly different effects from each other, except for open surgery which resulted in overall improvement and a significant reduction in long-term pain intensity. Invasive procedures should not be the first choice in the treatment of DDwoR, however, the literature suggests that open surgery should be considered a possibility for the most severe cases.