Scientific evidence in surgery for the treatment of temporomandibular joint internal derangement

Introduction

Many temporomandibular joint (TMJ) pathologies have been reported to be subsidiary for surgical treatments, such as degenerative joint disease, rheumatoid or infectious arthritis, mandibular recidivant luxation, anchylosis, condylar hiper-/hypo-plasia, and tumors, being internal derangement (ID) the most prevalent and the focus of the present review [Figure 1]. According to the American Association of Oral and Maxillofacial Surgeons, surgery of the TMJ is indicated when: (1) conservative treatment has failed and pain or disfunction are moderate to severe; (2) quality of life is worsened with conservative treatment; and/or (3) prognosis is worse if the disease is left to its natural evolution. Also, it is supported by the presence of disc displacement in the magnetic resonance imaging, although this condition is not imperative in terms of surgical indication. Meanwhile, surgery is clearly not indicated in: (1) asymptomatic or scarcely-symptomatic patients; and (2) in patients without pain and with satisfactory mandibular function.

Figure 1. Temporomandibular joint pathologies candidate for surgical treatment

The Evidence-Based Medicine (EBM) is defined as an approach to medical practice intended to optimize the decision-making by emphasizing the use of evidence from well-designed and well-conducted research. It may be necessary to make a precise question, search proofs in the literature, make a critical evaluation of the evidence, and wether it is found adequate, applicate this new knowledge to the practice [Figure 2]. Generally speaking, literature regarding treatment of TMJ disease lacks of studies with a high degree of evidence, which is mainly supported by systematic reviews (SRs) and randomized controlled trials (RCTs).

Figure 2. Global steps in Evidence-Based Medicine

In the present paper the author makes a non-systematic review of the literature in relation to the degree of the existing scientific evidence regarding the uselfuness of surgery for the treatment of ID of the TMJ, in order to provide an overall view of the state of the art regarding this topic.

Bibliography search

A bibliography search on MEDLINE, EMBASE and the Cochrane library databases for studies published from March 2000 to March 2019 was conducted, with the searching terms: (“temporomandibular joint disease” [MeSH Terms]) OR (“temporomandibular joint dysfunction” [MeSH Terms]) OR (“temporomandibular joint síndrome” [MeSH Terms] AND “surgery” [All Fields]) OR (“surgical treatment” [All Fields]) OR (“arthroscopy” [All Fields]) OR (“arthroscopic surgery” [All Fields]). References were explored to identify other articles.

Only those studies published in the English language and those dealing with “surgical treatment of the temporomandibular joint internal derangement” were selected, excluding those referring to other temporomandibular joint diseases not specifically classified as TMJ ID. Then, a manual screening of articles’ abstracts was performed in order to explore the role of surgery in the management of internal derangement or dysfunction of the TMJ from the ultimate complete 19 years. The following technical bibliographic exclusion criteria were applied: (1) case reports; (2) technical reports; (3) animal or in vitro studies; (4) review articles; (5) uncontrolled clinical studies; and (6) non-surgical methods were used for managing TMJ ID, including arthrocentesis. The abstracts of yielded results were reviewed and the full text of those with apparent relevance was obtained. The references of identified articles were crosschecked for unidentified articles. The author carefully assessed the eligibility of all studies retrieved from the databases. A total amount of 12 original papers were finally selected according to the provided inclusion and exclusion criteria^[1-12].

Evidence in surgical treatment of TMJ ID

Main schemes in EBM clasiffication

Regarding classification, the US Agency for Healthcare Research and Quality (AHRQ) classified the levels of scientific evidence in: (1) 1a-SRs of RCTs; (2) 1b-at least 1 RCT; (3) 2a-at least 1 well-designed controlled study without randomization; (4) 2b-at least 1 other type of well-designed quasi-experimental study; (5) 3-well-designed non-experimental descriptive studies such as comparative, correlation or cases-control; and (6) 4-expert committee reports or opinions [Figure 3].

Figure 3. Levels of evidence by the US Agency for Healthcare Research and Quality

Also, the Oxford Centre for Evidence-Based Medicine (OCEBM) decided to report on its classification system. In the highest level of evidence the SRs of RCTs are found, followed by individual RCTs; in a second degree of evidence, SRs of cohort studies followed by individual cohort studies are placed; in a third degree of evidence SRs of case-controlled studies followed by individual case-control studies are found; last, case series and expert opinions occupy the lowest steps in terms of evidence [Figure 4].

Figure 4. Levels of evidence by the Oxford Centre for Evidence-Based Medicine

Other widely used systems for hierarchying the evidence are those from the National Health and Medical Research Council, the National Institute for Health and Clinical Excellence, the Canadian Task on Force on the Periodic Health Examination, the United States Preventive Services Task Force, and the Scotish Intercollegiate Guidelines Network, among others.

RCTs

When considering individual RCTs or evidence 1b in both the AHRQ and the OCEBM classifications, a few relevant papers were found. Holmlund et al.^[8] compared the effectiveness of open surgery by discectomy vs. arthroscopic lysis and lavage (ALL) in 22 patients with DDwoR. They concluded that both open surgery (by discectomy) and ALL were equally effective in the treatment of DDwoR and that, as far as arthroscopy was a minimally-invasive procedure, it should be considered the first choice among surgical treatments.

With the same approach in 2007, Politi et al.^[9] compared the effectiveness of open surgery, in this series by high condilectomy and disc reposition, vs. ALL, in 20 patients with DDwoR under the design of a RCT. They concluded that both open surgery (by high condilectomy plus disc reposition) and ALL were equally effective in the treatment of DDwoR. As the previous authors, they recommended arthroscopy as the first choice among surgical options.

When specifically dealing with arthroscopic intraarticular injection of substances, Fernández Sanromán et al.^[10] in a randomized prospective clinical study in 92 patients with Wilkes stage IV internal derangement, showed significant reduction of pain and significant increase in mouth opening for both groups of patients treated either with plasma rich in growth factors (PRGF) or with saline solution, with no differences among treatment modalities. They concluded that the injection of PRGF did not add any significant improvement to clinical outcomes at 2 years post-op in those patients with advanced disease. However, in a posterior study by the same group, Fernández-Ferro etal.^[11] in another randomised prospective clinical study with a total of 100 patients with ID with osteoarthritis treated arthroscopically either with intra-articular injection of PRGF or hyaluronic acid (HA), concluded that the injection of PRGF following arthroscopy was more effective than the injection of HA regarding pain reduction, although no statistical differences wer observed in relation to the increase of mouth opening, being both methods effective in the management of advanced ID.

In contrast to most reported RCTs, Schiffman et al.^[12] compared the effectiveness among 4 treatment options in patients with chronic closed lock (CCL) or DDwoR: drugs, physiotherapy, arthroscopy and open surgery. They concluded that in patients with CCL, short term improvement (3 months) in terms of pain and function was equal for the 4 treatment options, while no additional improvement from surgery over conservative treatment was observed; for these authors primary treatment of DDwoR should consist on drug therapy or physiotherapy. Now this asseveration is difficult to maintain for patients with CCL of the TMJ, as it has been clinically observed that function in terms of mouth opening does not substantially improve by only conservative treatments in this group of patients. Moreover, the inclusion of this RCT as part of posteriorly published SRs may have had a clear deletereous effect in trying to probe the usefulness of pure surgical options. The major criticism to the conclusions of the previously mentioned study is that it grossly understimate the observed benefits of surgical treatments for TMJ ID, which have been extensively reported in many clinical series, specially for those patients who are refractory to conservative options.

At this point, it is convenient to remember that when dealing with surgical fields, particularly regarding TMJ surgery, it is very difficult to elaborate recommendations from studies with the highest degree of evidence. To illustrate this idea, Smith and Pell^[13] performed a SR of RCTs dealing with the effectiveness on the use of the parachute to prevent damage from gravitational falling. Not surprisingly, they found that its usefulness had not been yet demonstrated by the EBM. This is the reason why in normal clinical practice evidence present in 2b and 3 well-designed studies are stimated enough to guide the clinician in relation to the surgical treatment of TMJ ID.

Overall report

While the highest levels of evidence are strongly supported in many medical fields, Gonçalves et al.^[14] and Harris et al.^[15] have stated that scientific evidence 2b and 3 should be considered as evidence enough to guide clinical protocols in many surgical areas, including Oral and Maxillofacial Surgery. Thus, well-designed quasi-experimental (defined by a broad range of non-randomized intervention studies, usually made when it is not logistically feasible or ethical to conduct a RCT) and well-designed non-experimental descriptive studies are of undoubtful usefulness in our field.

This general idea was also supported by Melo et al.^[16] who stated that when studies with a high level of evidence on a given subject are not available, observations from case reports and case series can provide clinical information for consideration by the surgical community until cohort studies or RCTs can be conducted.

Based on the present review, the studies with highest evidence conclude that: (1) high-degree evidence is insufficient in relation to the effect of surgery; (2) surgery is useful in patients refractory to conservative treatment; (3) there are not differences among surgical techniques; (4) arthroscopy and arthrocentesis are effective in the treatment of chronic closed lock. Although both open surgery and arthroscopy are effective in treating patients with TMJ internal derangement, arthroscopy is preferred as the first option due to its non-invasive nature.

For a deepest knowledge of this field, the TMJ surgeons’ community should encourage researchers to: (1) design new randomized controlled trials (RCTs); (2) include patients with accurate diagnoses and categorized by Wilkes’ stages; (3) eliminate bias in relation to Cochrane recommendations for elaborating RCTs; (4) design multi-center studies based on accurate clinical practice protocols; (5) elaborate clinical guides by National and International Expert Committees.

Conclusion

In summary, surgical treatment of the TMJ based on evidence is present in a moderate degree, as studies with the highest evidence are scarce. Specially for patients with TMJ internal derangement, surgical treatment is highly supported by the results of large series by experienced surgeons, and the recommendations from societies of experts in TMJ surgery such as the European Society of TMJ Surgeons (ESTMJS) and the American Society of TMJ Surgeons.