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

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González-García. Stomatological Dis Sci 2019;3:5
DOI: 10.20517/2573-0002.2018.26 Stomatological Disease
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Scientic evidence in surgery for the treatment of
temporomandibular joint internal derangement
Raúl González-García
Department of Oral and Maxillofacial-Head and Neck Surgery, University Hospital of Badajoz, Badajoz 06080, Spain.
Correspondence to: Dr. Raúl González-García, Calle Los Yébenes 35, 8C, Madrid 28047, Spain. E-mail: raulmaxilo@gmail.com
How to cite this article: González-García R . Scientific evidence in surgery for the treatment of temporomandibular joint internal
derangement.
Stomatological Dis Sci
2019;3:5. http://dx.doi.org/10.20517/2573-0002.2018.26
Received: 15 Nov 2018 Fir
s
t Decision: 14 Mar 2019 Revised: 8 Apr 2019 Accepted: 15 Apr 2019 Published: 29 May 2019
Science Editors: Nikolaos G. Nikitakis, Dimitrios Dionysopoulos Copy Editor: Cai-Hong Wang Production Editor: Huan-Liang Wu
Abstract
Temporomandibular joint (TMJ) internal derangement (ID) is the most prevalent indication for surgery among TMJ
pathology. Generally considered the literature lacks studies with the highest evidence -which is mainly supported by
systematic reviews and randomized controlled trials- regarding the usefulness of surgery in the management of TMJ
ID. The objective of the present manuscript is to report the actual knowledge in terms of surgical treatment of TMJ ID
considering scientific evidence criteria. A non-systematic review in 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 is performed. A bibliography
search on MEDLINE, EMBASE and the Cochrane library databases for studies published from March 2000 to March
2019 was conducted. The author only included studies published in the English language and those dealing with “surgical
treatment of temporomandibular internal derangement”; The following technical bibliographic exclusion criteria were
applied: (1) case reports; (2) technical report; (3) animal or
in vitro
studies; (4) review articles; (5) uncontrolled clinical
studies; and (6) publications in which the same data were published by the same group of researchers. The abstracts
of yielded results were reviewed and the full text of those with apparent relevance was obtained. Several results must
be highlighted from the evaluation of the literature with the highest degree of evidence: (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 of the TMJ. 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 ID, surgical treatment must be highly
supported by the results of large series by experienced surgeons and recommendations from societies of experts in TMJ
surgery.
Keywords:
Evidence-based medicine, temporomandibular joint internal derangement, surgical treatment

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 le 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.
e Evidence-Based Medicine (EBM) is dened 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).
In the present paper the author makes a non-systematic review of the literature in relation to the degree of
the existing scientic 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. e abstracts of yielded results were reviewed and the full text
of those with apparent relevance was obtained. e references of identied articles were crosschecked for
unidentied articles. e author carefully assessed the eligibility of all studies retrieved from the databases.
A total amount of 12 original papers were nally selected according to the provided inclusion and exclusion
criteria[1-12].
EVIDENCE IN SURGICAL TREATMENT OF TMJ ID
Main schemes in EBM clasiffication
Regarding classication, the US Agency for Healthcare Research and Quality (AHRQ) classied the levels
of scientic evidence in: (1) 1a-SRs of RCTs; (2) 1b-at least 1 RCT; (3) 2a-at least 1 well-designed controlled
Page 2 of 8 González-García. Stomatological Dis Sci 2019;3:5 I http://dx.doi.org/10.20517/2573-0002.2018.26

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].
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
González-García. Stomatological Dis Sci 2019;3:5 I http://dx.doi.org/10.20517/2573-0002.2018.26 Page 3 of 8
Figure 1. Temporomandibular joint pathologies candidate for surgical treatment
Figure 2. Global steps in Evidence-Based Medicine

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].
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.
SRs
Summarizing the philosophy undergoing the usefulness of surgical treatment of TMJ ID, a letter by Hall[1]
approached the results by some meta-analyses and RCTs about pain relief in TMJ surgical procedures,
establishing that prompt relief of pain was one of the chief reasons for most patients looking for surgical
treatment. As reminded in author’s comment, a placebo eect may account for some of the improvement
after operation, but it should be expected no more than 30%-35% of the pain relief. These findings may
justify that surgery may be undoubtedly responsable for such improvement in terms of pain. is autor also
concluded that although evidence was imperfect, major joint operations were eective in the management of
the painful TMJ with ID.
When considering SRs or evidence 1a in both the AHRQ and the OCEBM classifications, some relevant
papers were found, such as the one by Reston and Turkelson[2] in 2003, who evaluated the effectiveness
of different surgical modalities in the treatment of TMJ ID: arthrocentesis, arthroscopy, discectomy and
discopexy. ey concluded that: (1) surgical treatments were benecial for patients who were refractory to
conservative treatments; (2) there were no dierences between the analyzed surgical options; and (3) there
was evidence about the eectiveness of arthrocentesis and arthroscopy for the treatment of patients with
disc displacement without reduction (DDwoR).
Figure 3. Levels of evidence by the US Agency for Healthcare Research and Quality
Page 4 of 8 González-García. Stomatological Dis Sci 2019;3:5 I http://dx.doi.org/10.20517/2573-0002.2018.26

In 2010, List and Axelsson[3] tried to evaluate the evidence and quality of SRs published in relation to the
treatment of TMJ disorders. A total amount of 30 studies were included, 23 of them qualitative and 7
quantitative. Among them, only 3 studies approached the surgical treatment of TMJ ID, which is a clear
indication of the paucity of SRs dealing with surgical treatment of TMJ ID. In the group of patients with
DDwoR, the comparison between arthrocentesis, arthroscopy and discectomy did not show any statistical
difference. Also, in the group of patients with disc displacement with reduction (DDwR) there were not
dierences between arthrocentesis, arthroscopy and conservative treatment by physiotherapy. ese authors
concluded that evidence was not enough in relation to the eect of surgery, while the main limitation of the
analyzed SRs was that the variability of the primary studies did not allow to establish rm conclusions.
Only one year later, Rigon et al.[4] performed a SR dealing with the effectiveness of arthroscopy vs. open
surgery, arthrocentesis and conservative treatment in TMJ ID, in relation to pain, function and clinical
signs. ey found 7 RCTs and 349 patients meeting the inclusion criteria. ey concluded that in patients
with closed lock, open surgery reduced pain more than arthroscopy, from the 12th month post-operatively.
Also, they reported that, in patients with DDwR or DDwoR, arthroscopy obtained better results in terms of
mouth opening than arthrocentesis, from the 12th month post-operatively.
Besides, De Souza et al.[5] in a SR of the published literature, reviewed the evidence concerning several
treatments for TMJ osteoarthritis. ey only found 3 RCTs comparing dierent treatments. eir results
were that: (1) there were no dierences between the injection of sodium hyaluronate and the injection of
corticoids; (2) there were no dierences between diclofenac sodium an occlusal splint therapy; and (3) there
were no dierences between glucosamine sulfate and ibuprofen. e concluded that there was a noticeable
lack of RCTs dealing with surgical treatments and that the lack of data from RCTs made decision-making
about the management of TMJ osteoarthritis strongly dependent on consumers´preferences and clinical
expertise.
Figure 4. Levels of evidence by the Oxford Centre for Evidence-Based Medicine
González-García. Stomatological Dis Sci 2019;3:5 I http://dx.doi.org/10.20517/2573-0002.2018.26 Page 5 of 8

Fricton et al.[6] reviewed the evidence concerning several treatments for TMJ disorders. ey performed a
quality assessment of 210 RCTs checking the internal and external validity using the Consolidated Standards
of Reporting Trials criteria. ey concluded that the overall quality of the reviewed studies was modest, with
only 58% of the quality criteria met, while only 10% of the RCTs met the four most important criteria. In
contrast to these discouraging data, they also assessed that there had been a trend towards improvement in
studies quality over time.
To assess wether arthroscopy or arthrocentesis was most eective, Al-Moraissi[7] performed a SR and meta-
analysis on the management of TMJ ID. Two RCTs, 2 non-randomized clinical controlled trials, and 2
cases series were included. Based on this work, the author concluded that arthroscopy was observed to be
superior than arthrocentesis in increasing joint movement and decreasing pain, while both arthroscopy and
arthrocentesis had comparable post-operative complication rates. e main limitation of this study was that
meta-analysis was incomplete due to the paucity of good quality studies in the high-impact, peer-reviewed
literature.
RCTs
When considering individual RCTs or evidence 1b in both the AHRQ and the OCEBM classications, a few
relevant papers were found. Holmlund et al.[8] compared the eectiveness of open surgery by discectomy vs.
arthroscopic lysis and lavage (ALL) in 22 patients with DDwoR. ey concluded that both open surgery (by
discectomy) and ALL were equally eective in the treatment of DDwoR and that, as far as arthroscopy was a
minimally-invasive procedure, it should be considered the rst choice among surgical treatments.
With the same approach in 2007, Politi et al.[9] compared the eectiveness 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.
ey concluded that both open surgery (by high condilectomy plus disc reposition) and ALL were equally
eective in the treatment of DDwoR. As the previous authors, they recommended arthroscopy as the rst
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 signicant reduction of pain and signicant increase in mouth opening for both groups of patients
treated either with plasma rich in growth factors (PRGF) or with saline solution, with no dierences among
treatment modalities. ey concluded that the injection of PRGF did not add any signicant 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 et al.[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
eective than the injection of HA regarding pain reduction, although no statistical dierences wer observed
in relation to the increase of mouth opening, being both methods eective 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. ey 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 dicult 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
Page 6 of 8 González-García. Stomatological Dis Sci 2019;3:5 I http://dx.doi.org/10.20517/2573-0002.2018.26

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 eect in trying to probe the usefulness of pure
surgical options. e major criticism to the conclusions of the previously mentioned study is that it grossly
understimate the observed benets 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 eectiveness 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. is 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 elds, Gonçalves et al.[14] and
Harris et al.[15] have stated that scientic 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 (dened 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 eld.
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 dierences among surgical techniques; (4) arthroscopy and arthrocentesis are
eective in the treatment of chronic closed lock. Although both open surgery and arthroscopy are eective
in treating patients with TMJ internal derangement, arthroscopy is preferred as the rst 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.
González-García. Stomatological Dis Sci 2019;3:5 I http://dx.doi.org/10.20517/2573-0002.2018.26 Page 7 of 8

DECLARATIONS
Authors’ contributions
González-García R contributed solely to this sthdy.
Availability of data and materials
Not applicable.
Financial support and sponsorship
None.
Conflicts of interest
e author declared that there are no conicts of interest.
Ethical approval and consent to participate
Not applicable.
Consent for publication
Not applicable.
Copyright
© e Author(s) 2019.
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