下颌髁突脱位骨折后颞下颌关节软组织改变的MRI表现

目的 分析下颌髁突脱位骨折后颞下颌关节(TMJ)软组织改变的MRI表现.方法 应用矢状面和冠状面质子密度加权成像(PDWI)和T2WI连续检查103侧(77例)患有下颌髁突脱位骨折的颞下颌关节(TMJ).结果 MRI上,103侧髁突脱位骨折后的TMJ异常表现有:(1)髁突骨折断片向前下(102侧,99.0%)和前(1侧,10%)脱位;(2)关节盘移位(100侧,97.1%),其中矢状面MRI显示关节盘随脱位的髁突向前下移位者99侧,向前移位者1侧;(3)关节腔积液(103侧,100%);(4)关节盘后区信号异常(91侧,88.3%);(5)关节盘下后附着异常(89侧,86.4%);(6)关节囊异常(89侧,86.4%);(7)关节盘上后附着异常(37侧,35.9%);(8)关节盘变形(8侧,7.8%);(9)关节盘撕裂(8侧,7.8%);(10)颞骨关节窝骨折(4侧,3.9%).结论矢状面MRI上,多数下颌髁突脱位骨折以TMJ关节盘随脱位的髁突向前下移位,并伴有关节腔积液为特点.     

Usefulness of cone beam computed tomography in temporomandibular joints with soft tissue pathology

Objective

The aim of the study was to evaluate the usefulness of cone beam CT (CBCT) in temporomandibular joints (TMJs) with soft tissue pathology.

Methods

106 TMJs of 55 patients with temporomandibular disorder (TMD) were examined by MRI and CBCT. MR images were used for the evaluation of disc displacement, disc deformity, joint effusion and obscurity of temporal posterior attachment (TPA). CBCT images were evaluated for the presence or absence of osseous abnormalities. The χ² test was used to analyse the association between MRI and CBCT findings.

Results

MRI of 106 TMJs revealed disc displacement, disc deformity, joint effusion and obscurity of the TPA in 68, 73, 28 and 27 joints, respectively. Of the 68 TMJs with disc displacement, anterior disc displacement without reduction (ADDWR) was seen most frequently (47/68). CBCT imaging found 65 TMJs were characterized by the presence of osseous abnormalities and were significantly associated with disc deformity and ADDWR (P < 0.05). There was no statistically significant association between the presence of joint effusion and obscurity of TPA and TMJ osseous abnormalities.

Conclusions

TMD patients with confirmed ADDWR or disc deformity on MRI are at risk of having osseous abnormalities in the TMJ and further examination with CBCT is recommended.     

Temporomandibular joint and 3.0 T pseudodynamic magnetic resonance imaging. Part 2: evaluation of articular disc obscurity

Objectives

This study examined the relationship between temporomandibular joint (TMJ) dysfunctions and obscurity grades of interpreted anterior and posterior borders of the articular disc (Da and Dp, respectively) by 3.0 T pseudodynamic MRI.

Methods

Da and Dp were classified into seven obscurity grades, and the Dp contour was classified into three types. The grades, types and TMJ function were compared by 3.0 T pseudodynamic MRI.

Results

Unobscured Da images at condylar positions posterior to the articular eminence were associated with normal TMJ function (P = 0.046 < 0.05). Unobscured Dp images at condylar positions anterior to the articular eminence were associated with normal TMJ function (P = 0.033 < 0.05). In addition, unobscured Dp images following flap insertion were associated with normal TMJ function (P = 0.043 < 0.05). There was no statistical relationship between Dp contour types and TMJ movement, but any change observed in the Dp contour during mouth opening was associated with abnormal TMJ function (P = 0.040 < 0.05).

Conclusions

Grading of Da and Dp obscurity based on how well the areas were defined in the images, identifying the condylar positions in relation to the glenoid fossa and articular eminences, and observing the changes in Dp contour types were useful for diagnosing TMJ abnormalities.     

TMJ disorders and pain: assessment by contrast-enhanced MRI

Though magnetic resonance (MRI) is a widely accepted standard for the assessment of patients with temporomandibular joint (TMJ) disorders, efforts to correlate symptoms to MRI findings have often given controversial results. Aim of this study was to investigate the correlation between TMJ pain and findings of contrast-enhanced MRI. Thirty-eight consecutive patients with TMJ dysfunction syndrome (study group) were examined with MRI. Protocol included T2 turbo spin-echo sequence, T1 spin-echo sequence, and T2 gradient-echo (acquired with closed jaw, at intermediate and maximal opening). Post-contrast phase was obtained through a fat sat 3D T1 gradient-echo sequence (VIBE). Post-contrast findings in the study group were matched with those obtained in a control group of 33 patients submitted to MRI of the paranasal sinuses. Statistically significant difference was found between condylar medullary bone enhancement in painful TMJ, in painless TMJ and control group. In addition the average thickness of joint soft tissue enhancement in painful TMJ was superior to painless TMJ (p<0.0001) and to control group. On multivariate logistic regression analysis, the odds ratio that a painful TMJ showed disk displacement, osteoarthrosis, effusion and JST enhancement were 3.05, 3.18, 1.2 and 11.36, respectively. Though not histologically proven, TMJ enhancement could reflect the presence of inflammation in painful joints. Furthermore, the administration of contrast could be of help for the assessment of patients with orofacial pain, particularly when clinical exploration is insufficient to ascribe the pain to TMJ.     

Association between high signal intensity in the posterior disc attachment seen on T2 weighted fat-suppressed images and temporomandibular joint pain

OBJECTIVES: We sought to determine whether high signal intensity in the posterior disc attachment (PDA) seen on T2 weighted fat-suppressed MRI is associated with temporomandibular joint (TMJ) pain and joint pathology. METHODS: This study was based on 283 TMJs of 177 patients (31 males and 146 females, mean age 32.7 years) with TMJ disorders showing anterior disc displacement. MRI evaluation included assessment of signal intensity in the PDA and TMJ status (disc displacement with reduction, disc displacement without reduction and disc displacement with bone changes). Clinical criteria that were considered positive indicators of TMJ pain included the presence of pre-auricular pain during palpation, jaw function and assisted or unassisted mandibular opening. Association of signal intensity in the PDA with joint pain and TMJ status was analysed using chi2 test. RESULTS: Joint pain was reported in 47 (77.0%) out of 61 joints with high signal intensity in the PDA and in 97 (43.7%) out of 222 joints with low signal intensity in the PDA (P<0.0001). High signal intensity in the PDA correlated closely with more advanced joint pathology. In joints with anterior disc displacement with bone changes, TMJ pain was more commonly reported in joints with high signal intensity in the PDA than with low signal intensity in the PDA (P<0.0001). CONCLUSIONS: High signal intensity in the PDA on T2 weighted fat-suppressed MRI is associated with TMJ pain in TMJ disorders with anterior disc displacement with bone changes in the mandibular condyles.     

Temporomandibular joint and 3.0 T pseudodynamic magnetic resonance imaging. Part 1: evaluation of condylar and disc dysfunction

Objectives

This study describes an improved method for examining and diagnosing temporomandibular joint (TMJ) dynamics by 3.0 T pseudodynamic MRI.

Methods

Clinical observation and conventional static MRI of volunteers (one without and eight with TMJ arthrosis) were followed by 3.0 T pseudodynamic MRI in positions ranging from the mouth closed to mouth fully opened. Condylar head (Cd), articular disc anterior border (Da) and articular disc posterior border (Dp) were digitized on sagittal images to determine trajectory and velocity patterns.

Results

Patients were divided into three groups based on the presence or absence of dysfunction: Group 1, no dysfunction on the right or left side of the TMJ; Group 2, dysfunction on the right or left side of the TMJ; and Group 3, dysfunction on both the right and left sides of the TMJs. In 75% of patients (12 of 16 joints), pseudodynamic TMJ analysis was useful for determining a functional abnormality. Using a points system based on three trajectory and seven velocity patterns, discs with adhesion and perforation had significantly fewer points than discs with anterior displacement (with and without reduction) and discs with no abnormality (P = 0.019 < 0.05).

Conclusions

Trajectory and velocity patterns based on 3.0 T pseudodynamic MRI identified the affected side and determined the extent of morbidity in the Cd as well as the Da and Dp. The typical abnormal movement pattern of discs with anterior displacement (with and without reduction) and pathological structural changes of the articular disc (such as adhesion and perforation) could be identified.     

Severity of synovium and bone marrow abnormalities of the temporomandibular joint in early rheumatoid arthritis: role of gadolinium-enhanced fat-suppressed T1-weighted spin echo MRI

PURPOSE: Our goal was to evaluate the efficacy of dynamic contrast-enhanced fat-suppressed MRI of the temporomandibular joint (TMJ) in detecting early joint involvement in patients with rheumatoid arthritis (RA). METHOD: Conventional T1- and T2-weighted, gadolinium-enhanced T1-weighted, and dynamic gadolinium-enhanced fat-suppressed SE imaging sequences were performed in 22 patients with RA. RESULTS: The dynamic gadolinium-enhanced fat-suppressed T1-weighted SE sequence was more sensitive than the other techniques in detecting early changes in inflamed synovium of periarticular tissue and in detecting condylar bone marrow involvement. In patients with RA, 17 joints with joint pain showed synovial proliferation in 10 (59%) cases and joint effusion in 4 (24%). Of 14 joints with joint sound, 4 (29%) showed synovial proliferation and 7 (50%) showed joint effusion. A lower positional change of the disk was observed in joints with RA than in those with TMJ disorders (82 patients). CONCLUSION: Gadolinium-enhanced fat-suppressed MRI was extremely effective in diagnosing early changes of the inflamed TMJ.     

MRI evaluation of TMJ internal derangement: Degree of anterior disc displacement correlated with other TMJ soft tissue and osseous abnormalities

Objective

To evaluate the relationship between anterior disc displacement (ADD) degree and other temporomandibular joint (TMJ) soft tissues and osseous abnormalities in symptomatic TMJ dysfunction based on magnetic resonance imaging findings.

Patients and methods

MR images of 106 TMJs in 53 patients, presented with symptomatic TMJ dysfunction were included. Degree of ADD was detected and its relationship to joint effusion, retrodiscal layer integrity, thickness of lateral pterygoid muscle (LPM) attachments, degenerative changes and condylar position and translation as well as clinical manifestations was studied.

Results

Compared with normal disc position, risk of joint effusion and degenerative changes were significantly increased with increased degree of ADD (p < 0.05). LPM attachment thickening and retrodiscal layer abnormalities are significantly associated with an advanced degree of ADD (p < 0.05). Risk of ADD is significantly increased with posterior position of the condyle within the fossa.

Conclusion

There is a direct relationship between the ADD degree and other TMJ soft tissues and bone abnormalities as well as the severity of clinical manifestations, so early MRI detection and reporting of ADD degree and other MRI findings might help clinicians in full assessment and determining strategy of management of TMJ dysfunction.     

Is high-resolution ultrasonography suitable for the detection of temporomandibular joint involvement in children with juvenile idiopathic arthritis?

Objectives:

The purpose of this study was to determine the potential of high-resolution ultrasonography for the detection of temporomandibular joint (TMJ) changes in children with juvenile idiopathic arthritis (JIA).

Methods:

We investigated prospectively 20 children (17 female and 3 male; mean age 11.06 years, standard deviation 3.43 years) with TMJ disorders caused by JIA, over a period of 16 months. Using a 12 MHz array transducer, four images in each TMJ (160 images) were acquired. Each image was analysed with regard to five different aspects (condylar erosion, thickness of the condylar disc, synovial thickness, joint effusion and enlargement of the intra-articular space).

Results:

Diagnosis of JIA was ensured for every child and involvement of the TMJ was proven by MRI. Overall 287 changes (35.9%) were detected by using high-resolution ultrasonography. On 124 images (77.5%) condylar erosions were diagnosed; on 55 images (34.4%) synovial thickness was abnormal; on 48 images (30%) we could see higher thickness of the condylar disc; on 40 images (25%) irregularities of the bony surface were detected; and on 20 images (12.5%) we found joint effusion.

Conclusion:

High-resolution ultrasonography could be a sufficient diagnostic method, especially for the detection of condylar involvement in children with JIA, even if not all parts of the TMJ are visible for ultrasonography. High-resolution ultrasonography is a valuable tool in particular situations: (i) when MRI examination is not available; (ii) when children fear MRI examination; (iii) in more advanced stages of JIA; and (iv) for monitoring the progression of TMJ involvement and response of therapy.     

Temporomandibular internal derangement: correlation of MRI findings with clinical symptoms of pain and joint sounds in patients with bruxing behaviour

OBJECTIVES: The aim of this study was to correlate magnetic resonance imaging (MRI) findings of effusion, disc displacement, condylar bony changes and disc form with clinical findings of pain and sounds in patients with bruxing and non-bruxing behaviour. METHODS: Disc displacement was confirmed by MRI in 102 joints from 64 patients (total of 128 joints) with bruxing behaviour who were referred for clinically diagnosed internal derangements of the temporomandibular joint (TMJ). Sixty joints with internal derangement from 30 patients without bruxing behaviour served as a control group. The clinical inclusion criteria were pain in the pre-auricular area and muscles of mastication, limitation or deviation in mandibular range of motion, and TMJ sounds. Signs of bruxism were diagnosed clinically and were obtained from the patient's history given on their first visit. Pain was evaluated using a visual analogue scale. RESULTS: Of the 102 joints in the study group with disc displacement, 53 (52%) showed disc displacement with reduction and 49 (48%) showed disc displacement without reduction. In the control group, 16 joints were classified as normal. Of the remaining 44 joints, 27 (61%) had disc displacement with reduction and 17 (39%) had unilateral disc displacement without reduction. Condylar bony changes were seen in 55% of the reducing joints in the study group and in 38% of the reducing joints in the control group, compared with 86% of the non-reducing joints in the study group and 24% of the non-reducing joints in the control group. There was a strong correlation between age and degenerative change in the study group. In the reducing joints, there was a significant difference in the prevalence of condylar bony changes between the study and control groups (P<0.01). In non-reducing joints, 30% of painful joints in the study group and 59% of those in the control group showed a strong signal in the joint space on T(2) weighted imaging. Statistically significant differences between the study and control groups were also found for disc form and the prevalence of effusion and disc displacement. Joint sounds were important in unilaterally affected joints in the study group. A statistically significant correlation was found between joint sounds and reducing joints (P<0.05). CONCLUSION: It was demonstrated that a higher prevalence of condylar bony changes occurred in reducing joints in patients with bruxing behaviour.     

MRI analysis of the relationship between bone changes in the temporomandibular joint and articular disc position in symptomatic patients

Objectives

The aim of this study was to investigate bone changes in the condyle, articular eminence and glenoid fossa in relation to the position of the articular disc.

Methods

148 temporomandibular joints (TMJs) of 74 symptomatic patients who underwent MRI were evaluated. The position of the disc was classified as either normal (N), disc displacement with reduction (DDwR), disc displacement without reduction (DDwoR) and posterior displacement (PD). Bone changes were investigated in the condyle and temporal components of the TMJ and classified as osteophytosis, sclerosis or erosion.

Results

There were no bone changes in the glenoid fossa of the temporal bone. Of the total number of TMJs studied, 94 (63.5%) were N, 34 (23%) presented DDwoR, 19 (12.8%) presented DDwR and 1 (0.7%) presented PD. The bone changes in the condyle and posterior aspect of the articular eminence were associated with the position of the disc. The bone changes in the anterior aspect of the articular eminence were not associated with the position of the disc.

Conclusion

In cases of DDwoR, bone changes in the condyles were more common. The combination of erosion and osteophytosis in the condyle and the bone changes of the posterior aspect of the articular eminence were associated with disc position.     

Application of T1 Map Information Based on Synthetic MRI for Dynamic Contrast-Enhanced Imaging: A Comparison Study with the Fixed Baseline T1 Value Method

ObjectiveFor an accurate dynamic contrast-enhanced (DCE) MRI analysis, exact baseline T1 mapping is critical. The purpose of this study was to compare the pharmacokinetic parameters of DCE MRI using synthetic MRI with those using fixed baseline T1 values.Materials and MethodsThis retrospective study included 102 patients who underwent both DCE and synthetic brain MRI. Two methods were set for the baseline T1: one using the fixed value and the other using the T1 map from synthetic MRI. The volume transfer constant (K^trans), volume of the vascular plasma space (v_p), and the volume of the extravascular extracellular space (v_e) were compared between the two methods. The interclass correlation coefficients and the Bland-Altman method were used to assess the reliability.ResultsIn normal-appearing frontal white matter (WM), the mean values of K^trans, v_e, and v_p were significantly higher in the fixed value method than in the T1 map method. In the normal-appearing occipital WM, the mean values of v_e and v_p were significantly higher in the fixed value method. In the putamen and head of the caudate nucleus, the mean values of K^trans, v_e, and v_p were significantly lower in the fixed value method. In addition, the T1 map method showed comparable interobserver agreements with the fixed baseline T1 value method.ConclusionThe T1 map method using synthetic MRI may be useful for reflecting individual differences and reliable measurements in clinical applications of DCE MRI.     

MRI characteristics of anterior disc displacement with and without reduction

OBJECTIVES: The aim of this study was to investigate the differences between magnetic resonance imaging (MRI) characteristics of anterior disc displacement with reduction (ADDR) and without reduction (ADDWR). METHODS: A clinician and a radiologist, blinded to the results of the clinical examination, independently evaluated the MRI scans of 100 subjects with symptoms of temporomandibular joint (TMJ) disorders. The final sample included 88 subjects in whom there was consensus of disc displacement both between observers and between MRI and clinical examination. There were 130 joints with ADDR and 45 joints with ADDWR in the study. The MRI characteristics such as position, signal intensity and morphology of the disc, degenerative changes, effusion, scar tissue, osteonecrosis and condylar hypermobility were evaluated in the cases of ADDR and ADDWR. The chi(2) test was used to determine the differences between ADDR and ADDWR for these MRI characteristics. RESULTS: There were no significant differences between ADDR and ADDWR for effusion and degenerative changes. There were significant differences between ADDR and ADDWR for sideways displacement, disc deformation, signal intensity changes, scar tissue, osteonecrosis and condylar hypermobility. CONCLUSIONS: Degenerative changes and effusion did not appear to be markers of either ADDR or ADDWR. However, the severity of these abnormalities may be correlated with the type of internal derangement. The prevalence of sideways displacement, disc deformation, signal intensity changes, scar tissue, and osteonecrosis was greater in ADDWR than ADDR. These conditions may be considered to be indicators of more advanced and complicated stages of internal derangement. Because the percentage of subluxation was greater in ADDR, localized joint laxity and internal derangement may be correlated.     

Web-based calibration of observers using MRI of the temporomandibular joint

Objectives

Research diagnostic criteria for temporomandibular disorders (RDC/TMDs) were proposed in 1992 with the aim of standardizing and testing methods for diagnosing TMDs. RDC/TMDs have so far been lacking standardized methods for imaging and criteria for imaging diagnosis of disorders of the temporomandibular joint (TMJ). Criteria for disorders of the TMJ have recently been proposed for MRI. The aim of this study was to publish MR images of the TMJ on the web and to test the agreement of five observers using the criteria.

Methods

20 cases of MRI of the TMJ were published on the web together with the criteria. The MR images were taken in closed and open mouth positions, and sagittal and coronal views. Five observers diagnosed disc position, disc shape, joint effusion and loose calcified bodies in the TMJ.

Results

In all cases except one, three or more observers agreed upon the diagnosis. All agreed on whether a loose calcified body was present or not. The second best agreement was obtained for disc position in the sagittal view, where all observers agreed in 16 of the 20 cases. For disc position in the coronal view and the evaluation of the disc shape, observer agreement was lower.

Conclusion

Criteria were useful in order to standardize and simplify evaluation and thereby probably increase the diagnostic outcome among different observers for MRI of the TMJ. We recommend that the criteria be used internationally to facilitate comparisons between different studies.     

Correlation between disc displacements and locations of disc perforation in the temporomandibular joint

Objectives

The aim of this study was to investigate the correlation between disc displacement types and locations of disc perforation in the temporomandibular joint (TMJ).

Methods

157 patients (162 joints) with disc perforation observed through arthroscopy were included in this study. The types of disc displacement were analysed by TMJ MRI before operation. The locations of disc perforation under arthroscopy were recorded. The correlation between types of disc displacement and locations of disc perforation was analysed by Fisher''s exact test.

Results

Medial disc perforation was observed in 55.6% of patients with anterolateral displacement without reduction, but was observed in only 3.7% of patients with pure anterior displacement, and was not observed in patients with anteromedial displacement without reduction. There was a statistically significant difference between these groups in the incidence of medial disc perforation.

Conclusions

There is a correlation between different disc displacements and locations of disc perforation. The incidence of medial disc perforation in patients with anterolateral displacement was significantly higher. The types of disc displacement may have direct influence over the locations of disc perforation.     

Correlation between temporomandibular joint morphology and disc displacement by MRI

Objectives:

The aim was to evaluate the morphology of the temporomandibular joint''s (TMJs) disc and condyle as well as its correlation with disc displacement, using MRI.

Methods:

190 TMJs were retrospectively analysed. The condyle morphology of each TMJ was evaluated by two observers using both axial and coronal views, as were their disc morphology and displacement, using sagittal view. Condyle morphology was classified as flat, convex, angled or rounded in the coronal sections and as anterior side flat/posterior side convex, biconvex, anterior side concave/posterior side convex, flat or biconcave in the axial view. Disc morphology was determined as biconcave, biplanar, biconvex, hemiconvex or folded. χ², Fisher exact and Bonferroni correction tests were used to evaluate the data. ANOVA followed by post hoc Tukey''s test was used to evaluate the interaction between age and disc displacement.

Results:

Anterior disc displacement with reduction; convex condyle morphology in the coronal view; anterior side concave/posterior side convex morphology in the axial view; and biconcave discs were found to be the most prevalent findings. An association was observed between disc morphology and disc displacement (p < 0.001). No correlation between condyle morphology and TMJ disc displacement was found (p = 0.291 for axial and p = 0.14 for coronal views).

Conclusions:

The results of this study suggest that TMJ disc morphology is associated with disc displacement.     

MR tomographic diagnosis of internal derangement of the temporomandibular joint]

On the basis of MR imaging studies in 150 temporomandibular joints (TMJ) a classification system for internal derangement of the TMJ was defined. Clinically, internal derangement is characterized by disc displacement and disorders of the mandibular condyle. MR imaging enables a differentiation of early stages (I,II) with disc displacement, the intermediate stage (III), and the later stages (IV,V) with osseous destruction. Optimal diagnostic results (n = 140) allowed the use of proton-density sequences in both open and closed joint positions (TR/TE = 1000/28). Dynamic imaging of the TMJ was performed using fast-gradient echo sequences and a self-developed hydraulic opening device (n = 20). MR imaging has proved to be the method of choice for the pre- and post-therapeutic evaluation of internal derangement of the TMJ.     

Dynamic MRI of the TMJ under physical load

Objectives:

The objective of this study was to examine the kinematics of structures of the temporomandibular joint (TMJ) under physiological load while masticating.

Methods:

Radial MRI was chosen as a fast imaging method to dynamically capture the motions of the joint’s anatomy. The technique included a golden ratio-based increment angle and a sliding window reconstruction. The measurements were performed on 22 subjects with and without deformation/displacement of the intra-articular disc while they were biting on a cooled caramel toffee.

Results:

The reconstructed dynamic images provided sufficient information about the size and localization of the disc as well as the change of the intra-articular distance with and without loading.

Conclusions:

The feasibility of the golden ratio-based radial MRI technique to dynamically capture the anatomy of the TMJ under physical load was demonstrated in this initial study.     

Magnetic resonance images of patients with temporomandibular disorders: Prevalence and correlation between disk morphology and displacement

Using magnetic resonance imaging (MRI), this study aimed to evaluate the morphology of the articular disc of the temporomandibular joint (TMJ) in patients with temporomandibular disorder (TMD). There were 218 TMJ of 109 assessed patients; 88 were females and 21 males, and all were diagnosed as symptomatic for temporomandibular disorder. The articular disc positions were classified in the normal position and with anterior disc displacement with and without reduction. Regarding the morphology, the discs were classified as follows: biconcave (normal), biplanar, rounded, biconvex, folded, thickening in the posterior band, thickening in the anterior band and hemiconvex. The results indicated that females were the most affected by morphological changes of the articular disc (p = 0.008/Cramer's V = 0.295). There was no statistical significance when correlating the disc morphology with the sides (right and left). There was a significant correlation between the position and morphology of the articular disc (p < 0.001/Cramer's V = 0.609), and in the normal position of the discs presenting biplanar and biconcave morphologies. In TMJ with anterior displacement of the disc with reduction (ADDR), there was a greater correlation with rounded, hemiconvex and biconvex morphologies. Already in the TMJ with displacement without reduction (ADDWR), there was a higher prevalence of folded discs. It can be concluded that morphological changes in the disc are influenced by the type of displacement, and more serious deformations are associated with ADDWR cases.