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Individual MRI features of the temporomandibular joint are not predictive of TMJ pain
DIAGNOSIS & SCREENING
A RTICLE A NALYSIS &
Individual MRI features of the temporomandibular joint are not predictive of TMJ pain
E VALUATION Original Article
Level of Evidence
Purpose
Source of Funding
Type of Study/Design
Emshoff R, Brandlmaier I, Bertram S, Rudisch A. Relative odds of temporomandibular joint pain as a function of magnetic resonance imaging findings of internal derangement, osteoarthrosis, effusion, and bone marrow edema. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2003;95(4):437–45.
4
Do MRI variables such as disc displacement, osteoarthrosis, effusion, and/or bone marrow edema predict the presence of TMJ pain? Information not available
Cross-sectional
Summary SUBJECTS The study group consisted of 169 patients (144 females, 25 males) referred to the Orofacial Pain and Temporomandibular Disorder (TMD) Clinic at the University of Innsbruck, Austria, from June 1999 to January 2001. These patients had unilateral or bilateral temporomandibular joint (TMJ) pain and/or signs and symptoms consistent with a disc displacement with or without reduction. In these same patients, TMJs that were not painful were evaluated as control joints. DIAGNOSTIC TEST Magnetic resonance imaging was conducted for both TMJs. Conditions of disc displacement with or without J Evid Base Dent Pract 2004;2:150-2 D 2004 Mosby, Inc. All rights reserved. doi:10.1016/j.jebdp.2004.03.010
150
reduction, osteoarthritis, effusion, and bone marrow edema were assessed from the MRI for each TMJ. These conditions have traditionally been considered as a cause of TMJ pain and may reflect inflammation and/or anatomical remodeling that has occurred or is active in the joint.
DISEASE OR CONDITION THAT IS TO BE DIAGNOSED The primary condition to be identified was pain in the TMJ. MAIN RESULTS The frequencies of TMJs with pain and a single diagnosis of internal derangement, osteoarthrosis, effusion, or bone marrow edema were significantly different from TMJs without pain and the same diagnosis using
TABLE 1. Diagnostic value of MRI features of the temporomandibular joint to predict joint pain Diagnostic Test Value Sensitivity Specificity Pretest Probability Posttest Disease Probability Positive Test Posttest Disease Probability Negative Test Likelihood Ratio of a Positive Finding Likelihood Ratio of a Negative Finding
Internal derangementdisplaced disc with reduction
Internal derangementdisplaced disc without reduction
Osteoarthrosis
Effusion
Bone Marrow Edema
0.44 0.61 0.38 0.42
0.66 0.63 0.51 0.65
0.82 0.29 0.49 0.53
0.44 0.72 0.49 0.6
0.25 0.86 0.49 0.62
0.36
0.36
0.37
0.43
0.46
0.71
1.87
1.11
1.49
1.64
0.56
0.56
0.59
0.74
0.84
Adapted from Emshoff et al (2003), Table II.
chi-square testing. When multiple diagnoses were considered using multiple logistic regression analysis, osteoarthrosis, effusion, and bone marrow edema were not significantly different in the TMJ pain compared to the no-pain groups. In addition, no significant increases in risk of TMJ pain were found for joints with a displaced disc with reduction in combination with osteoarthrosis and either bone marrow edema (odds radio [OR] = 2.0:1) or effusion (OR = 1.2:1). However, significant increases in risk of TMJ pain were found for joints with a displaced disc without reduction in combination with osteoarthrosis and either bone marrow edema (OR = 3.7:1) or effusion (OR = 2.8:1).
Commentary CONCLUSIONS On the basis of this study, MRI of TMJ features, such as internal derangement, osteoarthrosis, effusion, and bone marrow edema, may not individually be considered highly predictive of TMJ pain. However, the presence of multiple MRI features with a displaced disc without reduction increased the proportionate risk of TMJ pain. ANALYSIS The ability to detect or diagnose pain in the TMJ using independent measures is a goal that has been sought by many clinicians and scientists. The traditional apJournal of Evidence-Based Dental Practice Volume 4, Number 2
proach has been to examine the anatomy or architecture of the joint using nonsurgical techniques such as manual palpation or radiography or imaging of the joint. However, the current knowledge of pain mechanisms does not always include overt damage to anatomical structures or extensive inflammation. Such examples of sympathetically maintained pain or localized regions of neurogenic inflammation may not appear in any imaging technique. Central pain processing can also be enhanced by peripheral and central sensitization. Pain medications can also affect the perceived level of pain. These different components can modulate TMJ pain and must be properly evaluated in a study of pain. Moreover, the detection of the same image features in non-painful joints further weakens the association of image features as a predictor of joint pain. Therefore, the ability to predict pain based solely on anatomical features can be problematic. The patient selection criteria, diagnostic criteria, and MRI feature criteria were weaknesses in the design of the study. The authors have not provided a detailed assessment of the patients that were selected to ensure a homogeneous sample. For example, it is unclear whether these patients were taking any medications. Although the diagnoses are supposed to be based on the Research Diagnostic Criteria (RDC) for TMD,1 the techniques used to evaluate the clinical signs and the cutoff used for a specific diagnosis were inconsistent with the RDC. For example, the RDC does not include auscultation of the joint but instead requires manual Emshoff et al 151
palpation. The criterion for a diagnosis of myofascial pain (or myalgia, as in this paper) is 3 or more muscle sites with pain (pain scores of 1, 2, or 3), not 2 or more (with pain scores of 2 or 3) as used in this study. The definition of osteoarthrosis in the RDC includes the lack of TMJ arthralgia, whereas the lack of pain is not a criterion in the determination of a diagnosis of osteoarthrosis in this study. These different techniques from the RDC may not have the reliability and validity necessary for consistent evaluation of patients. Likewise, the parameters for assessment of MRI features were not operationalized for reliable detection. Although normal disc position was stated, no reference was given to establish this 12 o’clock position and no criteria were provided for anterior, anteromedial, anterolateral, medial, or lateral disc positions. The assessment of osteoarthrosis from an MRI is also problematic because the lack of signal in cortical bone and tendon does not allow the clear identification of an osteophyte from a tendinous attachment of muscle. It is also conceivable that features such as effusion and bone marrow edema are automatically expected with a displaced disc without reduction and no methods to reduce this potential bias by the rater were incorporated into the research design. The authors have examined MRI features and have tested for differences in the proportions of each of these features in pain and non-pain TMJs and have identified statistically significant differences. This approach, unfortunately, does not provide the necessary information to test the predictive ability of the image features. Likewise, calculation of the odds ratio when using the contralateral non-painful TMJ as a control also has little meaning because one TMJ condition may affect the other (i.e., lack independence).
152
Emshoff et al
Based on the authors’ data, calculations of sensitivity, specificity, and other parameters that reflect the predictive ability of the anatomical features of the TMJ can be determined (table). It was found that none of the individual parameters perform with adequate sensitivity, specificity, and likelihood ratio of a positive finding to predict TMJ pain with a high level of accuracy. The authors also concluded that these individual MRI features were not adequate predictors for pain, but stated that combinations of features may be required to increase the diagnostic ability. However, no data were presented to reflect calculations of diagnostic performance using the presence of multiple MRI features. Finally, to adequately assess the MRI features as predictors of pain, an independent group of patients needs to be studied to assess performance. Without such testing in adequate numbers of patients with these multiple features, the predictive ability of this technique remains uncertain. The high cost of testing using MRI is also a limitation of the generalized applicability of the technique. At the present time, asking the patient if they are in pain and the location may be the best gold standard that we have to accurately identify pain in the TMJ. REFERENCE 1. Dworkin SF, LeResche L. Research diagnostic criteria for temporomandibular disorders: review, criteria, examinations and specifications, critique. J Orofac Pain 1992;6:301-55.
Reviewer: Charles G. Widmer, DDS, MS University of Florida Gainesville, Florida
Journal of Evidence-Based Dental Practice June 2004
A RTICLE A NALYSIS &
Individual MRI features of the temporomandibular joint are not predictive of TMJ pain
E VALUATION Original Article
Level of Evidence
Purpose
Source of Funding
Type of Study/Design
Emshoff R, Brandlmaier I, Bertram S, Rudisch A. Relative odds of temporomandibular joint pain as a function of magnetic resonance imaging findings of internal derangement, osteoarthrosis, effusion, and bone marrow edema. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2003;95(4):437–45.
4
Do MRI variables such as disc displacement, osteoarthrosis, effusion, and/or bone marrow edema predict the presence of TMJ pain? Information not available
Cross-sectional
Summary SUBJECTS The study group consisted of 169 patients (144 females, 25 males) referred to the Orofacial Pain and Temporomandibular Disorder (TMD) Clinic at the University of Innsbruck, Austria, from June 1999 to January 2001. These patients had unilateral or bilateral temporomandibular joint (TMJ) pain and/or signs and symptoms consistent with a disc displacement with or without reduction. In these same patients, TMJs that were not painful were evaluated as control joints. DIAGNOSTIC TEST Magnetic resonance imaging was conducted for both TMJs. Conditions of disc displacement with or without J Evid Base Dent Pract 2004;2:150-2 D 2004 Mosby, Inc. All rights reserved. doi:10.1016/j.jebdp.2004.03.010
150
reduction, osteoarthritis, effusion, and bone marrow edema were assessed from the MRI for each TMJ. These conditions have traditionally been considered as a cause of TMJ pain and may reflect inflammation and/or anatomical remodeling that has occurred or is active in the joint.
DISEASE OR CONDITION THAT IS TO BE DIAGNOSED The primary condition to be identified was pain in the TMJ. MAIN RESULTS The frequencies of TMJs with pain and a single diagnosis of internal derangement, osteoarthrosis, effusion, or bone marrow edema were significantly different from TMJs without pain and the same diagnosis using
TABLE 1. Diagnostic value of MRI features of the temporomandibular joint to predict joint pain Diagnostic Test Value Sensitivity Specificity Pretest Probability Posttest Disease Probability Positive Test Posttest Disease Probability Negative Test Likelihood Ratio of a Positive Finding Likelihood Ratio of a Negative Finding
Internal derangementdisplaced disc with reduction
Internal derangementdisplaced disc without reduction
Osteoarthrosis
Effusion
Bone Marrow Edema
0.44 0.61 0.38 0.42
0.66 0.63 0.51 0.65
0.82 0.29 0.49 0.53
0.44 0.72 0.49 0.6
0.25 0.86 0.49 0.62
0.36
0.36
0.37
0.43
0.46
0.71
1.87
1.11
1.49
1.64
0.56
0.56
0.59
0.74
0.84
Adapted from Emshoff et al (2003), Table II.
chi-square testing. When multiple diagnoses were considered using multiple logistic regression analysis, osteoarthrosis, effusion, and bone marrow edema were not significantly different in the TMJ pain compared to the no-pain groups. In addition, no significant increases in risk of TMJ pain were found for joints with a displaced disc with reduction in combination with osteoarthrosis and either bone marrow edema (odds radio [OR] = 2.0:1) or effusion (OR = 1.2:1). However, significant increases in risk of TMJ pain were found for joints with a displaced disc without reduction in combination with osteoarthrosis and either bone marrow edema (OR = 3.7:1) or effusion (OR = 2.8:1).
Commentary CONCLUSIONS On the basis of this study, MRI of TMJ features, such as internal derangement, osteoarthrosis, effusion, and bone marrow edema, may not individually be considered highly predictive of TMJ pain. However, the presence of multiple MRI features with a displaced disc without reduction increased the proportionate risk of TMJ pain. ANALYSIS The ability to detect or diagnose pain in the TMJ using independent measures is a goal that has been sought by many clinicians and scientists. The traditional apJournal of Evidence-Based Dental Practice Volume 4, Number 2
proach has been to examine the anatomy or architecture of the joint using nonsurgical techniques such as manual palpation or radiography or imaging of the joint. However, the current knowledge of pain mechanisms does not always include overt damage to anatomical structures or extensive inflammation. Such examples of sympathetically maintained pain or localized regions of neurogenic inflammation may not appear in any imaging technique. Central pain processing can also be enhanced by peripheral and central sensitization. Pain medications can also affect the perceived level of pain. These different components can modulate TMJ pain and must be properly evaluated in a study of pain. Moreover, the detection of the same image features in non-painful joints further weakens the association of image features as a predictor of joint pain. Therefore, the ability to predict pain based solely on anatomical features can be problematic. The patient selection criteria, diagnostic criteria, and MRI feature criteria were weaknesses in the design of the study. The authors have not provided a detailed assessment of the patients that were selected to ensure a homogeneous sample. For example, it is unclear whether these patients were taking any medications. Although the diagnoses are supposed to be based on the Research Diagnostic Criteria (RDC) for TMD,1 the techniques used to evaluate the clinical signs and the cutoff used for a specific diagnosis were inconsistent with the RDC. For example, the RDC does not include auscultation of the joint but instead requires manual Emshoff et al 151
palpation. The criterion for a diagnosis of myofascial pain (or myalgia, as in this paper) is 3 or more muscle sites with pain (pain scores of 1, 2, or 3), not 2 or more (with pain scores of 2 or 3) as used in this study. The definition of osteoarthrosis in the RDC includes the lack of TMJ arthralgia, whereas the lack of pain is not a criterion in the determination of a diagnosis of osteoarthrosis in this study. These different techniques from the RDC may not have the reliability and validity necessary for consistent evaluation of patients. Likewise, the parameters for assessment of MRI features were not operationalized for reliable detection. Although normal disc position was stated, no reference was given to establish this 12 o’clock position and no criteria were provided for anterior, anteromedial, anterolateral, medial, or lateral disc positions. The assessment of osteoarthrosis from an MRI is also problematic because the lack of signal in cortical bone and tendon does not allow the clear identification of an osteophyte from a tendinous attachment of muscle. It is also conceivable that features such as effusion and bone marrow edema are automatically expected with a displaced disc without reduction and no methods to reduce this potential bias by the rater were incorporated into the research design. The authors have examined MRI features and have tested for differences in the proportions of each of these features in pain and non-pain TMJs and have identified statistically significant differences. This approach, unfortunately, does not provide the necessary information to test the predictive ability of the image features. Likewise, calculation of the odds ratio when using the contralateral non-painful TMJ as a control also has little meaning because one TMJ condition may affect the other (i.e., lack independence).
152
Emshoff et al
Based on the authors’ data, calculations of sensitivity, specificity, and other parameters that reflect the predictive ability of the anatomical features of the TMJ can be determined (table). It was found that none of the individual parameters perform with adequate sensitivity, specificity, and likelihood ratio of a positive finding to predict TMJ pain with a high level of accuracy. The authors also concluded that these individual MRI features were not adequate predictors for pain, but stated that combinations of features may be required to increase the diagnostic ability. However, no data were presented to reflect calculations of diagnostic performance using the presence of multiple MRI features. Finally, to adequately assess the MRI features as predictors of pain, an independent group of patients needs to be studied to assess performance. Without such testing in adequate numbers of patients with these multiple features, the predictive ability of this technique remains uncertain. The high cost of testing using MRI is also a limitation of the generalized applicability of the technique. At the present time, asking the patient if they are in pain and the location may be the best gold standard that we have to accurately identify pain in the TMJ. REFERENCE 1. Dworkin SF, LeResche L. Research diagnostic criteria for temporomandibular disorders: review, criteria, examinations and specifications, critique. J Orofac Pain 1992;6:301-55.
Reviewer: Charles G. Widmer, DDS, MS University of Florida Gainesville, Florida
Journal of Evidence-Based Dental Practice June 2004