Correlation between clinical diagnosis based on RDC/TMD and MRI findings of TMJ internal derangement

Int. J. Oral Maxillofac. Surg. 2012; 41: 103 108 doi:10.1016/j.ijom.2011.09.010, available online at http://www.sciencedirect.com Clinical paper TMJ disorders Correlation between clinical diagnosis based on RDC/TMD and MRI findings of TMJ internal derangement J. W. Park, H. H. Song, H. S. Roh, Y. K. Kim, J. Y. Lee Department of Oral Medicine & Oral Diagnosis, School of Dentistry & Dental Research Institute, Seoul National University, Yeongeon-Dong 28, Jongno-Gu, Seoul 110-749, Republic of Korea J. W. Park, H. H. Song, H. S. Roh, Y. K. Kim, J. Y. Lee: Correlation between clinical diagnosis based on RDC/TMD and MRI findings of TMJ internal derangement. Int. J. Oral Maxillofac. Surg. 2012; 41: 103 108. # 2011 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Abstract. This study was conducted to investigate the value of magnetic resonance imaging (MRI) in the diagnostic process based on the Research Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD) by evaluating agreement between RDC/TMD and MRI diagnosis of disc displacement (DD) and correlation amongst MRI findings such as DD, joint effusion (JE), degenerative change and superior lateral pterygoid muscle (SLPM) attachment. Randomly selected MRIs of 200 joints from 100 TMD patients differentiated into RDC/TMD group II representing DD by clinical examination were reviewed retrospectively. The results show that Cohen s kappa value was 0.336 showing overall disagreement between RDC/TMD group II and MRI diagnoses (P < 0.001). The Cohen s kappa value for group IIa, DD with reduction (DDWR), was 0.223 (P < 0.01) showing disagreement, whilst the value was 0.546 for group IIb, DD without reduction (DDWOR) with limited opening, and 0.490 for group IIc, DDWOR without limited opening, showing moderate agreement (P < 0.001). JE was detected with a higher probability as the state of DD advanced (P < 0.001) and when degenerative joint changes were present (P < 0.05). The difference of DD according to SLPM attachment was insignificant. MRI could be used when clinical examination cannot predict the true position of the disc. Keywords: temporomandibular disorders; magnetic resonance imaging; Research Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD); joint effusion; lateral pterygoid muscle; disc displacement. Accepted for publication 20 September 2011 Available online 13 October 2011 Clinical procedures to diagnose temporomandibular disorders (TMD) frequently consist of clinical examination and imaging. The clinical examination assesses the mandibular range of motion and associated pain, joint noises, and muscle and joint tenderness on palpation. Often the findings vary from one assessment to the next in the same individual since the patient s response to clinical examination may change according to the transient or recurrent nature of TMD and also due to the lack of reproducibility in examination technique. Efforts to standardise the examination procedure and enhance reliability resulted in the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/ TMD) by DWORKIN and LERESCHE 5. The RDC/TMD consists of guidelines and procedures that help the examiner to gain adequate inter-observer reliability by using diagnostic criteria for investigating muscle origin pain, disc displacement, and 0101-5027/010103 + 06 $36.00/0 # 2011 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

104 Park et al. arthralgia and degenerative bone change of the temporomandibular joint (TMJ). Imaging examination is not an essential procedure and is necessary only when additional information is needed to underline the results of the clinical examination, to facilitate the clinical diagnosis process, or to take a surgical intervention into consideration in cases that show a refractory nature in spite of sufficient conservative treatment. The original version of the RDC/TMD indicates that imaging may help to substantiate clinical impressions of bony or soft tissue abnormalities when TMJ arthropathy exists, but by itself lacks the ability to differentiate asymptomatic from symptomatic patients with a high predictive rate 5. Some studies report that the RDC/TMD classification of diagnoses based on clinical findings into muscle disorders, disc displacements or arthritis/arthrosis could not consistently be confirmed by findings made through magnetic resonance imaging (MRI) 2,10. MRI defines hard and soft tissue and is usually applied to examine the soft tissue pathology of the TMJ. Studies which compared MRI findings with surgical and autopsy specimens reported an accuracy of about 90 95% for detecting disc position abnormalities when both coronal and sagittal images were evaluated 17. Displacement of the articular disc is one of the major findings in TMD patients and is the most common cause of TMJ sounds. Disc displacement with reduction (DDWR) and disc displacement without reduction (DDWOR) are the two most common forms of disc displacement (DD) of the TMJ. A common symptom of DDWR is a reciprocal clicking of the TMJ, whereas DDWOR frequently limits mandibular mobility 9. A number of studies were conducted to evaluate the accuracy of clinical diagnosis of TMJ DD but findings are controversial due to the different criteria adopted and the investigation is limited to findings concerning the position of the disc and its reduction on mouth opening. This study was conducted to investigate the value of MRI in the diagnostic process based on the RDC/TMD by attempting to evaluate the agreement between RDC/ TMD and MRI diagnosis of DD. The authors also studied various MRI findings from different RDC/TMD group II patients and analysed their inter-relationship to describe the clinical implication of MRI findings such as DD, joint effusion (JE), degenerative change and lateral pterygoid muscle (LPM) attachment and address their significance in the pathophysiology and diagnosis of TMD patients. Materials and methods 200 joints of 100 patients that had been differentiated into RDC/TMD group II after clinical examination were randomly selected from patients presenting for TMD treatment from September 2009 to October 2010. A retrospective review of the TMJ MRI taken for the evaluation of TMD was conducted. The MRI of patients with major deformities, TMJ fractures or systemic diseases known to affect the TMJ, such as rheumatoid arthritis, were excluded from the study. Clinical records including clinical signs and symptoms, such as, pain and comfortable or maximum mouth opening range measured between upper and lower incisors were reviewed to confirm the initial diagnosis given according to the RDC/TMD. The subjects consist of 32 males and 68 females, and their mean age was 25.3 13.12 years and 31.9 12.3 years, respectively. The research protocol was approved by the Institutional Review Board of the University Hospital (#CR110036). RDC/TMD assessment Clinical assessment was conducted using a standardised clinical protocol including evaluation of patient history, palpation of TMJs, auscultation of joint noises and measurement of mandibular range of motion. According to the RDC/TMD guidelines 5, the patients were differentiated into three distinct groups. Disc position was categorised as: DDWR; DDWOR with limited mouth opening; DDWOR without limited mouth opening. Criteria for inclusion of joints in the different categories were as follows. More detailed clinical diagnostic criteria of all 3 RDC/TMD axis I groups are described in Table 1. RDC/TMD axis I group IIa, diagnosis of DDWR: either reciprocal clicking in TMJ (click on both vertical opening and closing that occurs at a point at least 5 mm greater interincisal distance on opening than on closing and is eliminated on protrusive opening), reproducible on two of three consecutive trials; or clicking in TMJ on both vertical range of motion (either opening or closing), reproducible on two of three consecutive trials, and click during lateral excursion or protrusion, reproducible on two of three consecutive trials. RDC/TMD axis I group IIb, diagnosis of DDWOR, with limited opening: history of significant limitation in opening; maximum unassisted opening 35 mm; passive stretch increases opening by 4 mm or less over maximum unassisted opening; contralateral excursion <7 mm and/or uncorrected deviation to the ipsilateral side on opening; absence of joint sounds, or presence of joint sounds not meeting criteria for DDWR. RDC/TMD axis I group IIc, diagnosis of DDWOR, without limited opening: history of significant limitation of mandibular opening; maximum unassisted opening >35 mm; passive stretch increases opening by 5 mm or more over maximum unassisted opening; contralateral excursion >7 mm; presence of joint sounds not meeting criteria for DDWOR. MRI of the TMJ MRI of the TMJ was taken with GE Signa Exite HD 1.5T. Images were digitally reconstructed and read by two examiners on a computer. To evaluate the inter- and intra-examiner reliability, images of 30 randomly selected patients were read twice at a 2-week interval by two examiners after mutual calibration. The degree of JE in the superior compartment on MRI was divided into 2 grades: absent, no area of high signal intensity; present, presence of any of the following: lining or spot of high intensity along the articular surface, band of high intensity, and collection with pooling in the compartment 13. The disc position of the TMJ was also determined with MRI. Normal position, when a disc in the superior position in the closed mouth position maintained a position interposed between the condyle and the articular eminence in the open mouth position. DDWR, when a displaced disc in the closed mouth position assumed a position interposed between the condyle and the articular eminence in the open mouth position. DDWOR, when a displaced disc in the closed mouth position did not achieve a position between the condyle and the articular eminence in the open mouth position 18. LPM attachments were categorised into two different types: type 1, where fibres of the superior head of the lateral pterygoid muscle (SLPM) were attached to the disc only; and type 2, where fibres of the SLPM were attached to both the disc and condyle 19. MRI diagnosis of degenerative change of the TMJ was defined by the presence or absence of the following changes: erosion, defined as an interruption or absence of the cortical lining; sclerosis, a condition in

RDC/TMD diagnosis and MRI findings 105 Table 1. Clinical diagnostic criteria of the RDC/TMD Axis I diagnosis 5. RDC/TMD group Diagnosis Definition Diagnostic criteria Group I Ia Myofascial pain Pain of muscle origin including a complaint of pain as well as pain associated with localised areas of tenderness to palpation in muscle. Ib Myofascial pain with limited opening Group II IIa Disc displacement with reduction IIb IIc Disc displacement without reduction, with limited opening Disc displacement without reduction, without limited opening Limited movement and stiffness of the muscle during stretching in the presence of myofascial pain. The disc is displaced from its position between the condyle and the eminence to an anterior and medial or lateral position, but reduces on full opening, usually resulting in a noise. Note that when this diagnosis is accompanied by pain in the joint, a diagnosis of arthralgia (IIIa) or osteoarthritis (IIIb) must also be assigned. A condition in which the disc is displaced from normal position between the condyle and the fossa to an anterior and medial or lateral position, associated with limited mandibular opening. A condition in which the disc is displaced from its position between the condyle and the eminence to an anterior and medial or lateral position, not associated with limited opening. Group III IIIa Arthralgia Pain and tenderness in the joint capsule and/or the synovial lining of the TMJ. IIIb IIIc Osteoarthritis of the TMJ Osteoarthrosis of the TMJ Inflammatory condition within the joint that results from a degenerative condition of the joint structures. Degenerative disorder of the joint in which joint form and structure are abnormal. 1. Report of pain or ache in the jaw, temples, face, preauricular area, or inside the ear at rest or during function; plus 2. Pain reported by the subject in response to palpation of three or more of the following 20 muscle sites (right side and left side count as separate sites for each muscle): posterior temporalis, middle temporalis, anterior temporalis, origin of masseter, body of masseter, insertion of masseter, posterior mandibular region, submandibular region, lateral pterygoid area, and tendon of the temporalis. At least one of the sites must be on the same side as the complaint of pain. 1. Myofascial pain as defined in Ia; plus 2. Pain-free unassisted mandibular opening of less than 40 mm; plus 3. Maximum assisted opening (passive stretch) of 5 mm or more greater than pain-free unassisted opening. 1. Either: (a) reciprocal clicking in TMJ (click on both vertical opening and closing that occurs at a point at least 5 mm greater interincisal distance on opening than on closing and is eliminated on protrusive opening, reproducible on two of three consecutive trials; or (b) click in TMJ on both vertical range of motion (either opening or closing), reproducible on two of three consecutive trials, and click during lateral excursion or protrusion, reproducible on two of tree consecutive trials. 1. History of significant limitation in opening; plus 2. Maximum unassisted opening 35 mm; plus 3. Passive stretch increases opening by 4 mm or less over maximum unassisted opening; plus 4. Contralateral excursion < 7 mm and/or uncorrected deviation to the ipsilateral side on opening; plus 5. Either: (a) absence of joint sounds, or (b) presence of joint sounds not meeting criteria for disc displacement with reduction. 1. History of significant limitation of mandibular opening; plus 2. Maximum unassisted opening > 35 mm; plus 3. Passive stretch increases opening by 5 mm or more over maximum unassisted opening; plus 4. Contralateral excursion 7 mm; plus 5. Presence of joint sounds not meeting criteria for disc displacement with reduction. 1. Pain in one or both joint sites (lateral pole and/or posterior attachment) during palpation; plus 2. One or more of the following self-reports of pain: pain in the region of the joint, pain in the joint during maximum unassisted opening, pain in the joint during assisted opening, pain in the joint during lateral excursion. 3. For a diagnosis of simple arthralgia, coarse crepitus must be absent. 1. Arthralgia; plus 2. Coarse crepitus in the joint. 1. Absence of all signs of arthralgia, i.e., absence of pain in the region of the joint, and absence of pain in the joint on palpation, during maximum unassisted opening, during maximum assisted opening, and on lateral excursions; plus 2. Coarse crepitus in the joint.

106 Park et al. Table 2. MRI features of different groups according to disc displacement. DD (N) Total (200) Normal (70) DDWR (54) DDWOR (76) Joint effusion *** Absent 78.6% (55) 75.9% (41) 40.8% (31) 63.5% (127) Present 21.4% (15) 24.1% (13) 59.2% (45) 36.5% (73) Attachment of SLPM Type 1 31.4% (22) 35.2% (19) 40.8% (31) 36.0% (72) Type 2 68.6% (48) 64.8% (35) 59.2% (45) 64.0% (128) Mouth opening limitation Absent 55.7% (39) 68.5% (37) 52.6% (40) 58.0% (116) Present 44.3% (31) 31.5% (17) 47.4% (36) 42.0% (84) Differences of frequencies were analysed by x 2 -test. *** P < 0.001. which bone density is significantly increased; flattening, defined as a loss of the round contour; osteophyte, defined as marginal hypertrophic bone formation 17. When more than one type of degenerative change was observed, the joint was determined to have degenerative change. Statistical analysis Cohen s kappa value was used to analyse the RDC/TMD diagnosis and MRI diagnosis reliability. The associations amongst DD, JE, degenerative change, and attachment of SLPM were analysed using the x 2 -test. All statistical analyses were performed with the PASW 18.0 program. Results Cohen s kappa value was 0.336 (P < 0.001) showing disagreement between RDC/TMD and MRI diagnoses. The Cohen s kappa value for the RDC/TMD IIa group that showed DDWR on MRI was 0.223 (P < 0.01) showing disagreement. The Cohen s kappa value for the RDC/ TMD IIb group that showed DDWOR on MRI and maximum mouth opening 35 was 0.546 (P < 0.001) showing moderate agreement. The Cohen s kappa value for the RDC/TMD IIc group that showed DDWOR on MRI and maximum mouth opening > 35 was 0.490 (P < 0.001) showing moderate agreement. JE was detected with a higher probability as the state of DD advanced (P < 0.001). 21% of those with a normal disc position and 24% of those with DDWR showed JE on MRI whilst 59% of those with DDWOR showed joint effusion on MRI. There was no significant difference in DD according to the attachment of SLPM. The SLPM appeared to be more commonly attached to both the disc and condyle in both DDWR and DDWOR. Although mouth opening limitation was most common with DDWOR, there was no significant difference in the presence of mouth opening limitation according to DD (Table 2). JE was detected with a higher probability when degenerative changes of the TMJ were present (P < 0.05). 31% of those without degenerative changes of the TMJ showed JE on MRI whilst 45% of those with degenerative changes of the TMJ showed JE on MRI (Table 3). JE was detected with a higher probability when clinical pain was present at the ipsilateral joint (P < 0.05). JE was detected in 43% of the joints that were painful whilst it was detected in only 29% of the non-painful joints (Table 3). Discussion By examining MRI of 200 joints of 100 patients, the results show that there is a discrepancy between RDC/TMD based diagnosis and MRI findings. The agreement between clinical and imaging-based diagnosis of disc displacement shows a Table 3. Presence of joint effusion according to degenerative changes of the TMJ condyle and presence of pain in the ipsilateral joint. Joint effusion (N) Absent Present Degenerative changes * Absent (118) 69.5% (82) 30.5% (36) Present (82) 54.9% (45) 45.1% (37) Pain in the ipsilateral joint * Absent (94) 71.3% (67) 28.7% (27) Present (106) 56.6% (60) 43.4% (46) Total (200) 63.5% (127) 36.5% (73) Differences of frequencies were analysed by x 2 -test. * P < 0.05. wide variation amongst previous studies, ranging from 59% to 90% 3,6,7. The results of this study are in accordance with previous reports that show such a disparity. Many authors suggest that clinical evaluation does not always allow an accurate assessment of the disc position and its reduction on mouth opening 2,6,24. According to the present results, such misdiagnosis was most frequent in DDWR. Such observations may be due to false positive MRI over-diagnosis rather than false negative clinical under-diagnosis. EMSHOFF and RUDISCH reported poor agreement between clinical assessment for the diagnosis of DDWR (k = 0.13), DDWOR (k = 0.33) and normal disc position (k = 0.18) and MRI findings, stating that clinical diagnostic criteria only had a 44% positive predictive value for the diagnosis of DDWR 6. As it can be seen in the present results, when there is no clinical mouth opening limitation the clinician is prone to diagnosis the joint as DDWR even when a clear joint noise is absent. On the other hand, YATANI et al. claimed that in spite of the poor predictability of historical or clinical findings to diagnose DDWOR, DDWR can be diagnosed relatively accurately through the use of clinical examination only 23,24. Such disagreement of previous results raises concerns about the role of MRI as an appropriate standard of reference for the diagnosis of disc condyle relationship. The difference in the reported values mostly depends on the diagnostic clinical criteria adopted. The RDC/TMD was applied in this study to overcome this variability and to increase reproducibility. To the authors knowledge, the RDC/ TMD has been adopted in only a few studies that concern MRI and clinical diagnosis of the TMJ 2,7,11,24. The results of this study suggest a possible role for MRI for the patients without mouth opening limitation but a questionable disc position. The results show characteristics such as effusion and attachment of SLPM according to different subgroups of the RDC/TMD group II which have not been

RDC/TMD diagnosis and MRI findings 107 reported previously. The results may provide information concerning the pathophysiology of DD. JE, which are defined as large retentions of fluid in the joint space have been reported to be associated with painful joints, and synovitis 22. The present results show that JE is observed more frequently in joints with DD. This is in line with previous results that show that there were significant relationships between effusion and the deformation of the disc and effusion and subluxation in DDWR 16. The occurrence of JE was about twice as likely when there was DDWR compared to normal discs and was even more frequently present in the presence of DDWOR. These results clearly demonstrate that joints with DD are more vulnerable to inflammatory changes of the joint. As described in a previous study, DD is a part of the internal derangement of the TMJ which is brought about from the maladaptation of the TMJ organ to functional demand exceeding the adaptive capacity of the joint 14. In the balance between adaptive capacity and the functional demand of the load-bearing system of the TMJ, the anterior position of the disc could even be a normal variant 14,15. Once the breakdown of this balance occurs due to any of the factors affecting the TMJ organ, shifting the tissue response of the TMJ to inflammation and changes in the tissues including the synovium, disc, retrodiscal tissue, and even the subchondral bone may begin. The anterior position of the disc of such a joint can no longer be labelled as a normal variant. The subjects of this study were TMD patients with clinical symptoms whose physiological balance of the TMJ organ could be said to have been tipped into the direction of overloading and inflammation. Whatever position the discs were observed to be on MRI, the joints had already been exposed to conditions that threatened the adaptive capacity of the TMJ. The fact that JE was more frequently associated with DD and pain implies that joints with DD are more vulnerable to inflammatory changes, but whether DD is causatively related to JE is unclear. The inflammatory environment may have caused the degenerative change of the TMJ since increased inflammatory cytokine levels are known to be associated with osteoarthritis of the TMJ 21. The LPM makes a unique contribution to jaw movement control by virtue of the attachments to both the TMJ disc and condyle. The SLPM primarily contributes to the apposition of disc, condyle, and eminence in jaw closing 1. The role of the superior head in influencing the disc condyle relationship with internal derangement and TMD is rarely considered. Some have stated that disc displacement of the TMJ is the result of contraction of muscles attached to the disc. Contraction of the LPM may readily cause anterior displacement of the disc. According to the study by TASKAYA- YILMAZ et al. 19, SLPM attached only to the disc were seen in 86% of all the DDWOR TMJs. It has been concluded that since the SLPM is only attached to the disc, the disc may displace anteriorly very easily. The findings of the present study did not support this view. A larger portion of the patients with DDWOR in this study were more likely to have a SLPM attached only to the disc but the difference between those with DDWR and normal disc position was not statistically significant. The pull on the disc caused by the SLPM may have aggravated the disc condyle relationship which had already been jeopardised by joint overloading but did not appear to place a significant burden on the position of the disc. This is in line with the reports of CARPENTIER et al. 4 that stated that considering the anatomic organisation of the upper head, the explanation of anterior DD due to a spastic activity of the SLPM alone is not probable. The occurrence of mouth opening limitation was not significantly different amongst normal, DDWR, and DDWOR groups. The reason for the lack of difference of mouth opening ranges may be due to the fact that remodelling of the TMJ tissue, including the disc, capsule, and retrodiscal tissues allow some patients to open their mouth widely despite DDWOR. Also the fact that those with DDWR were more likely to show limitation in condyle translation imply that the range of mouth opening is easily affected by various factors including pain and is highly subject dependent. The position of the TMJ disc should not be hastily predicted based on clinical mouth opening range or condyle position on radiographs. This study has a few limitations. First, the subjects of this study were randomly selected from a pool of TMD patients who actively sought care for a variety of reasons, including subjective discomfort, such as joint pain, joint noise, and mouth opening limitations. Results based on a general TMD patient population including those who did not seek medical service could yield different results. Second, when grouping the attachment of the SLPM the presence of a third head of muscle was not considered and differentiation was based on the uppermost head of the LPM. A few authors suggested that the LPM originates from three heads 8,20 but the presence of a third head is not routinely observed in MRI and the variation in the gross attachment of the upper head of the LPM to the disc and to the condyle has not been satisfactorily explained 12,19. This study was performed to define the MRI characteristics of TMJ DD patients who were diagnosed with DD based on the RDC/TMD. By grouping the patients following reliable and reproducible diagnostic criteria, the authors hoped the results might provide a clearer view of the MRI characteristics of TMJ DD and allow efficient comparison with data from other study groups. It is difficult to establish a cause-and-effect relationship of DD with other signs observed on the MRI, but by describing the characteristics one may gain practical knowledge for consideration in the management of the joint in which DD is found. MRI of patients with TMD signs or symptoms could be considered since clinical examinations have short comings in predicting the true position of the disc, especially in cases of DDWR. MRI provides information concerning soft tissue structure and inflammation that cannot be discerned through clinical observation. Such findings may be of value in investigating the aetiology of TMJ DD and provide further diagnostic criteria and treatment guidelines, especially in those cases in which surgical interventions are taken into consideration. MRI is a costly procedure that still has limitations for routine application and the results of this study may provide additional information for deciding on additional MRI procedures. Funding None. Competing interests None. Ethical approval Institutional Review Board of the Seoul National University Dental Hospital #CR110036. References 1. Aziz MA, Cowie RJ, Skinner CE, Abdi TS, Orzame G. Are the two heads of the human lateral pterygoid separate muscles? A perspective based on their nerve supply. J Orofac Pain 1998;12:226 38.

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Address: Department of Oral Medicine & Oral Diagnosis School of Dentistry & Dental Research Institute Seoul National University Yeongeon-Dong 28 Jongno-Gu Seoul 110-749 Republic of Korea Tel.: +82 2 2072 0212 fax: +82 2 744 9135 E-mail: jeongyun@snu.ac.kr