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Problem and objective: Anterior disc displacement is one of the functional diseases of the temporomandibular joint and at international level is also subsumed under the concept of internal derangement. Statements on the clinical picture of the internal derangement, in particular of the anterior disc displacement without reduction (ADDwoR), are not consistent in large parts and frequently even contradictory. So the multi-causal etiology and the pathogenesis which is not entirely clear yet already provide the basis for controversial discussion. The two considerable main objectives of this paper are:
(1) The acquisition of long-time results in patients with a WILKES classification IV as well as V following discectomy with a direct interposition of a double-layered temporal fascia flap taking into consideration functional parameters such as the index of HELKIMO and MFIQ. Furthermore, prognostic factors such as the degree of damage of the joint or the existence of a myofascial pain and dysfunctional syndrome (MPDS), having an impact on the functional outcome are investigated.
(2) The systematic analysis, comparison and assessment of international literature on (surgical) therapy of the anterior disc displacement without reduction.
Material and methods: This retrospective follow-up examination comprises 28 patients who had undergone surgical treatment at the clinic and outpatients‘ clinic for oral, jaw and facial surgery of the Philipps University in Marburg during the period from October 1996 to September 2006. The average follow-up period was ten years and three months. The clinical assessment of findings consisted of the following parameters: VAS, mouth opening, index of MFIQ, index of HELKIMO, joint noises and subjective parameters such as e.g. assessment of the chewing capability or satisfaction with surgery. Data evaluation was exclusively based on non-parametric test procedures. For all metric variables, comparisons have been carried out using the Mann-Whitney-U test (Wilcoxon signed rank test) and for all nominal variables using Fisher’s exact test (chi square test). A significance level of α < 0.05 was postulated. In addition, the 95 % confidence intervals for the function parameters described have been assessed as well. For the assessment of international literature a systematic online search in the PUBMED database and supplementarily in the database of the COCHRANE COLLABORATION has been carried out. The publications found have been assessed based on the evidence classification of the “Agency for Health Care Policy and Research (AHCPR)“ and an internal evaluation scheme for the validity of literature.
Results: The values for quoting pain intensity (VAS) related to the mean average have improved by 5.6 ± 2.6 from 7.5 ± 2.4 preoperative to 1.9 ± 2.4 postoperative. The maximum mouth opening prior to surgery was 24.8 ± 6.3 mm on average and has improved with an increase by 12.8 ± 9.0 mm to 37.6 ± 8.4 mm at the point of time of follow-up examination. The MFIQ point value was 50.6 ± 11.5 preoperative on average and 18.2 ± 16.3 postoperative on average. The improvement was 32.4 ± 13.9 points. All amendments were statistically significant (Mann-Whitney-U test: p < 0.001). The comparing analysis of the subpopulations with regard to prognostic factors for a successful outcome respectively did not reveal any statistical significance for the parameters WILKES stages, the existence of an MPDS as well as the impact of preoperative pain duration.
Discussion and conclusion: The results of the provision of patients with a double-layered temporal fascia flap following discectomy with regard to the functional outcome compared with the results published in international literature can be assessed as positive. The procedure particularly provides good long-time results. However, no “ideal“ or “the only correct“ therapy recommendation for an anterior disc displacement without reduction is possible based on the results of this paper as well as current literature search. Furthermore, current surveys do not either allow any statements at a higher evidence level indicating unambiguous prognostic factors for a successful surgical outcome. However, literature data presented in this paper impressively substantiates that the minimally invasive arthrocentesis with regard to pain reduction as well as a faster functional improvement is superior to conservative measures at a higher level of evidence (1b). Here it is required to break the dogma to always start therapy of the first choice purely conservatively. Lysis and lavage should find their way into treatment at an earlier point of time.