New observations with routine and CT-assisted arthrography in suspected internal derangements of the temporomandibular joint

oral surgery oral medicine oral pathology With sections on

endodonticsand dental radiology

Volume51, Number6, June,1981

oral surgery Editor: ROBERT B. SHIRA, D.D.S.

School of Dental Medicine, Tufts University I Kneeland Street Boston Massachusetts 02111

New observations with routine and CTassisted arthrography in suspected internal derangements of the

temporomandibularjoint R. W. Katzberg, M.D.,* M. F. Dolwick, D.M.D., Ph.D.,** D. A. Keith, B.D.S., F.D.S.R.C.S.,* C. A. Helms, M.D.,*** and W. C. Guralnick, D.M.D.,* Boston, Mass., San Antonio, Texas, and San Francisco, Calif. A simplified arthrotomographic technique has been performed successfully in more than 200 patients with symptoms referable to the temporomandibular joint. Soft-tissue abnormalities not detected by plain film radiography were demonstrated. Anterior meniscusdisplacement was the most significant finding in patients with unilateral pain and limitation of opening. New arthrographic observations and research imaging methods, including CT-assisted arthrography, are described. Leakage of contrast material along the lateral condylar neck in patients with anterior meniscus displacement suggests associated tearing of the lateral capsular attachment. Our results confirm that arthrography is a useful diagnostic procedure for suspected internal derangements of the temporomandibular joint.

I n cases of suspected internal derangement of the temporomandibular joint, normal plain radiographs do not exclude organic disease. We have developed a simplified arthrographic technique that can dem*Department of Radiology, Harvard Medical School; Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Boston, Mass. **Department of Oral and Maxillofacial Sugefy, University of Texas Health Science Center, San Antonio, Texas. ***Department of Radiology, University of California School of Medicine, San Francisco, Calif. 0030-4220/81/060569 + 06500.60/00 1981 The C. V. Mosby Co.

onstrate soft-tissue abnormalities. 1 In patients with the clinical findings of unilateral pain and limitation of opening, the radiographic images depicted anterior or anterolateral displacements of the meniscus.S, 3 This article will report additional arthrographic abnormalities that have been observed in association with meniscus displacement. New imaging methods are described. These allow an appreciation of the full scope of the soft-tissue damage which is undetected by plain film radiography. S69

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Fig. 1. A, Normal lower joint space in closed-mouth position. Small opacified anterior recess with smooth teardrop configuration delineates lower margin of anterior ridge of the meniscus. (Note: All radiographs are oriented with patient's facial region to reader's right.) B, Normal lower joint space in open-mouth position. The condyle has translated anteriorly. Contrast material is expressed out of anterior recess, and joint space opens posteriorly. Thin zone of the meniscus articulates with superior part of condyle and lower convexity of bony eminence.

Fig. 2. Anterior meniscus displacement and perforation. Maximal jaw opening and decreased excursion of condyle. Concave impression on anterior recess by anteriorly displaced meniscus (arrow). Note: Small amount of contrast material filling upper joint space (x) indicates perforation. (Compare with Fig. 1, A, and and B.)

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Fig. 4. Spot radiograph obtained during fluoroscopy and arthrography. Clear depiction of anterior meniscus displacement and decreased condylar excursion.

Fig. 3. A, Tomographic radiograph through far lateral aspect of joint space. Concave impression on anterior recess by displaced meniscus is most marked anterolaterally, suggesting lateral shift of meniscus and joint space. (Compare with Fig. 1, A and B.) B, Anteroposterior tomogram. Arrows delineate anterolateral displacement of meniscus in same patient.

CLINICAL MATERIAL AND METHODS

More than 200 arthrotomograms were performed and evaluated. About one third of the patients had symptoms of unilateral pain and limitation of opening at the time of the arthrogram. The findings in these patients will be the subject of this report. Clicking or popping within the joint was a very common symptom that preceded limitation of motion, and a few patients complained of a tearing or ripping sensation when forcibly opening the mouth. The arthrographic procedure has been described previously in detail. ~' ~ Briefly, it involves introduchag a 23-gauge 3.2 cm. temporomandibular joint needle (Ranfac, Avon, Mass.) perpendicularly through the skin and into the lower joint space under fluoroscopic observation. Spot radiographs in closed- and open-mouth views are then obtained for

diagnosis and to confirm successful injection of contrast material. Our patients were transferred to a multidirectional tomogram unit, where lateral tomograms were obtained with the mouth closed, just before the click, and with maximal jaw opening. Anteroposterior multidirectional tomograms were used in some patients to assess more fully the type of meniscus displacement. CT-assisted images were then obtained in a select few patients, as a research tool, immediately following the arthrotomograms. Informed consent was obtained with regard to additional radiation dosage. A lead shield of 2 mm. thickness was placed over the eyes and low milliamperage (mA) was used to further reduce the radiation dose. Scans were performed on an Ohio Nuclear 2020 2-second scanner in coronal and basilar 4 mm. thick images. These were compared to the arthrotomograms and to the clinical presentation. RESULTS

Anterior meniscus displacement without reduction was consistently demonstrated by arthrotomography in our patients. A normal arthrotomogram (Fig. 1) is shown for comparison with a typical arthrotomogram .of a patient with limitation of opening and anterior meniscus displacement (Fig. 2). The normal arthrotomogram shows free movement of contrast material from the anterior to the posterior recess, indicating normal meniscus function. In anterior displacement, the entire meniscus is located forward of the condyle, and this is depicted

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Fig. 5. A, Spot radiograph. Radiograph obtained at fluoroscopy appears normal but was exposed without special maneuvers. B, Arthrotomogram in same patient. Anterocentral displacement of the meniscus now clearly depicted.

Fig, 6 A, Arthrotomogram, closed-mouth position. Contrast material introduced into lower joint space in region of posterosuperior aspect of bony condyle. Arrowheads depict extravasation of contrast material dearly separate from injection site, along lateral condylar neck and caudal to anterior recess. B, Arthrotomogram in same patient during maximal opening of jaw. Concave impression on upper surface of anterior recess (arrow) indicating anterior meniscus displacement. Note decreased condylar excursion and contrast extravasation along condylar neck. by a smooth, concave impression on the anterior recess of the lower joint space. Maximal opening of the jaw has been attempted, but condylar translation is minimal. Anterolateral meninscus displacement may be demonstrated by employing anteroposterior arthrotomograms, as shown in another patient who expe-

rienced persistent pain and limitation of jaw opening (Fig. 3). The anterior recess of the lower joint space is shifted anterolaterally, and meniscus displacement without reduction is clearly demonstrated. It is most marked anterolaterally. A spot radiograph exposed in the lateral transcranial projection, following introduction of con-

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Fig. 6. (Cont'd). C, CT-assisted arthrogram in same patient (performed through base of skull). Arrows depict extravasated contrast material along lateral aspect of condylar neck, suggesting capsular tear with leakage, p, lateral pterygoid muscle; t, temporalis muscle; m, masseter muscle. D, CT-assisted arthrogram in same patient (performed in coronal plane). Arrows depict anterolateral shift of lower joint space in association with anterolateral meniscus displacement, p, lateral pterygoid muscle; pg, parotid gland.

trast material into the lower joint space, may also dearly depict anterolateral meniscus displacement (Fig. 4). In cases of anterocentral displacement of the meniscus, however, diagnosis by spot radiographs may require repositioning of the head with the face raised 15 degrees from the table top. The roentgen beam is also 30 degrees craniocaudal from beneath the table top during the injection. An example of a normal-appearing arthogram by spot film radiography is compared to an arthrotomogram that clearly demonstrates central-anterior meniscus displacement (Fig. 5). In many arthrotomograms of meniscus displacement without reduction, a moderate amount of

contrast material is visible along the posterior and lateral aspects of the condylar neck. Initially, we were concerned that this observation was the result of a faulty arthrotomographic technique. Although we now perform the technique with relative ease, we still frequently observe this distribution of contrast material well beyond the confines of the expected normal lower joint space. A CT-assisted arthrogram in a patient with contrast "leakage" along the neck of the condyle is shown in Fig. 6. A more cranialward CT image also confirms shift of the joint space anterolaterally (Fig. 6, D). The arthrotomogram depicts anterolateral meniscus displacement without reduction and accumulation of contrast material

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Fig. 7. Arthrotomogram, closed-mouth position, showing anterior meniscus displacement, perforation, and lymphatic visualization (arrows).

along the lateral condylar neck. This abnormality has often been observed in association with anterior meniscus displacement, and we believe that it represents evidence of a torn joint capsule. In one patient who had meniscus displacement without reduction and arthrographic evidence of capsular damage, we observed lymphatic filling following injection of contrast material into the lower joint space (Fig. 7). DISCUSSION

There is now considerable evidence that internal derangements of the temporomandibular joint can occur in patients with temporomandibular joint pain and limitation of opening who have normal plain radiographs: -9 Clinically, this may be preceded by clicking and/or intermittent limitation of opening and occasionally by an acute episode in which forcible opening of the mouth causes pain and a "tearing" or "ripping" sensation. Our hypothesis is that limitation of opening is due to a displacement of the meniscus, which may be intermittent and reducible, and that this displacement occurs as a result of damage to the posterior attachment of the meniscus. Indeed, in our series of more than 200 arthrotomograms, the most significant internal derangement was anterior or anterolateral displacement of the meniscus. We have now expanded our observations to suggest that capsular damage may also be associated with meniscus displacement. We believe that soft-tissue changes in these patients are more extensive in scope and significance than was previously appreciated.

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Further evidence of significant soft-tissue pathosis in the temporomandibular joint is provided by the first reported case of lymphatic visualization demonstrated in association with meniscus displacement and capsular tear. This finding by arthrography is quite rare, and it has never been described in the normal joint: ~ 11 In summary, we have observed significant softtissue abnormalities by arthrotomography and CTassisted arthrography in patients who show clinical evidence of internal derangements and normal plain radiographs. A normal plain radiograph does not validly exclude significant damage and dysfunction of the temporomandibular joint. We conclude that arthrotomography is a useful procedure that complements clinical diagnosis in evaluation of patients with suspected internal derangements. We wish to express our gratitude to Judith Lopez for her excellent secretarial assistance and John Buckley for his faithful reproduction of the radiographs. REFERENCES 1. Katzberg, R. W., Dolwick, M. F., Bales, D. J., and Helms, C. A.: Arthrotomography of the Temporomandibular Joint: New Technique and Preliminary Observations, Am. J. Roentgenol. 132: 949-955, 1979. 2. Dolwick, M. F., Katzberg, R. W., Helms, C. A., and Bales, D. J.: Arthrotomographic Evaluation of the Temporomandibular Joint, J. Oral Surg. 37: 793-799, 1979. 3. Katzberg, R. W., Dolwick, M. F., Helms, C. A., Hopens, T., Bales, D. J., and Coggs, G. C.: Arthrotomography of the Temporomandibular Joint, Am. J. Roentgenol. 134: 9941003, 1980. 4. Blaschke, D. D., Solberg, W. K., and Sanders, B.: Arthrography of the Temporomandibular Joint: Review of Current Status, J. Am. Dent. Assoc. 100: 388-395, 1980. 5. Carlsson, G. E.: Mandibular Dysfunction of Temporomandibular Joint Pathosis, J. Prosthet. Dent. 43: 658-662, 1980. 6. Farrar, W. B., and McCarty, W. L.: Inferior Joint Space Arthrography and Characteristics of Condylar Paths in Internal Derangements of the TMJ, J. Prosthet. Dent. 41: 548-555, 1979. 7. Helms, C. A., Katzberg, R. W., Dolwick, M. F., and Bales, D. J.: Arthrotomographic Diagnosis of Perforations of the Temporomandibutar Joint, Br. J. Radiol. 53: 283-285, 1980. 8. Toiler, P. A.: Opaque Arthrography of the Temporomandibular Joint, Int. J. Oral Surg. 3: 17-28, 1974. 9. Wilkes, C.: Arthrography of the Temporomandibular Joint in Patients With the TMJ Pain Dysfunction Syndrome, Minn. Med. 61: 645-651, 1978. 10. Coren, G. S., Curtis, J., and Dalinka, M. K.: Lymphatic Visualization During Hip Arthrography, Radiology 115: 621-623, 1975. 11. Lewin, J. R., and Mulhern, L. M.: Lymphatic Visualization During Contrast Arthrography of the Knee, Radiology 103: 577-579, 1972. Reprint requests to: Dr. R. W. Katzberg Department of Radiology Harvard Medical School 25 Shattuck St. Boston, Mass. 02115