Temporomandibular joint: MR assessment of rotational and sideways disk displacements

The accuracy of coronal and sagittal magnetic resonance (MR) imaging was examined in the assessment of rotational and sideways displacements of the temporomandibular joint (TMJ) disk. Rotational disk displacement implies a combination of anterior and medial or lateral displacements, whereas sideways displacement implies pure medial or lateral displacement without an anterior component. Multiple 3-mm-thick coronal and sagittal MR images were obtained of 18 fresh TMJ autopsy specimens and compared with the observations in corresponding coronal cryosections. MR imaging correctly delineated the mediolateral position of the disk in 15 joints (83%) and incorrectly delineated it in three joints (17%). Osseous anatomy was correctly assessed in 17 joints (94%). On cryosections, six joints (33%) showed medial disk displacement and two joints (11%) showed lateral displacement. In five of these eight joints the medial or lateral displacement occurred in conjunction with an anterior displacement, that is, rotational displacement. Clinical MR imaging in 37 patients (61 joints with coronal images) showed medial or lateral disk displacement in 16 joints (26%). This study suggests that rotational and sideways displacements of the TMJ disk are an important aspect of internal derangement. The multiplanar capabilities of MR are suitable for an assessment of these abnormalities.     

Prevalence of osseous changes in the temporomandibular joint of asymptomatic persons without internal derangement.

There is a controversy in the literature regarding the prevalence of osseous changes in the temporomandibular joint (TMJ) of asymptomatic persons. Using cephalometrically corrected tomograms, we assessed one TMJ of each of 34 asymptomatic persons who had no arthrographic or magnetic resonance imaging evidence of internal derangement. Minimal flattening of the condyle or articular eminence was seen in 12 joints (35%). More advanced osseous changes such as erosion, osteophytosis, or sclerosis were not seen in any joint. The findings suggest that generally no osseous changes occur in the TMJ in asymptomatic persons without internal derangement. When osseous changes occur, they are confined to minimal flattenings. Minimal flattening is probably of no clinical significance because the persons were asymptomatic, and arthrography and magnetic resonance imaging showed no evidence of abnormalities in the soft tissues.     

Clinical and radiological study of patients with anterior disc displacement of the temporomandibular joint

Patients displaying temporomandibular joint clicking or with a history of clicking followed by limitation of opening were subjected to clinical and radiological examinations including arthrography. Arthrotomographically the patients were found to have anterior displacement of the disc. In patients with clicking the disc was repositioned in association with clicking during opening. In patients with limitation of opening the disc was constantly displaced anterior to the condyle, blocking anterior condylar translation. The patients with limitation of opening had more pain, more signs of mandibular dysfunction, more hard tissue changes and more frequent perforation and deformation of the disc, compared to patients with clicking only. These findings may justify two different diagnoses, displacement with and without repositioning of the disc on opening. Displacement without repositioning seems to be the more advanced condition and may in some cases be a precursor of osteoarthrosis.     

Increased horizontal angle of the mandibular condyle in abnormal temporomandibular joints. A magnetic resonance imaging study

The horizontal condylar angle was measured in axial magnetic resonance images of normal and abnormal temporomandibular joints (TMJs). The average condylar angle in the normal joints was 21.2 degrees. In joints with disk displacement with reduction it was 29.7 degrees; joints with disk displacement without reduction, 33.5 degrees; and in joints with degenerative joint disease, 36.5 degrees. There were statistically significant differences between all four groups. Thus the condylar angle seemed to be increasingly larger with more advanced pathologic changes related to internal derangement and degenerative disease in the joint. The reason for the larger condylar angle in the abnormal joint was unclear. Joints with a larger condylar angle might have a greater tendency for internal derangement and degenerative joint disease to develop. Another possible explanation could be that remodeling associated with internal derangement and degenerative joint disease might result in a larger condylar angle. Further studies with longitudinal observations are needed to determine whether a causal relationship exists between the changes of the joint and a large condylar angle.     

Discectomy as an effective treatment for painful temporomandibular joint internal derangement: a 5-year clinical and radiographic follow-up.

PURPOSE: The purpose of this prospective study was to compare the preoperative and 5-year postoperative status of patients after unilateral discectomy for painful internal derangement of the temporomandibular joint. PATIENTS AND METHODS: The study was based on 64 patients. Fifty-six had disc displacement without reduction and 8 had disc displacement with reduction. The patients were examined clinically and radiographically before and 5 years after the operation according to a standardized protocol. RESULTS: Eighty-five percent of the patients (n = 52) had good results, 6% had acceptable results, and 9% had a poor outcome. Three patients (5%) were reoperated and 5 other patients (8%) needed a contralateral operation during the 5-year follow-up. The median increase in maximum mouth opening was 11 mm (range, -8 to +35 mm) and 83% of the patients had more than 40 mm maximal mouth opening postoperatively. Seventy-five percent of the patients had crepitation at 5-year follow-up compared with 27% before the operation. Postoperatively, the majority of the joints showed radiographic evidence of osteophytes, flattening, and sclerosis. The radiographic alterations did not correlate with the patients' symptoms. CONCLUSIONS: The results of this long-term follow-up after unilateral discectomy support the use of this operation in patients with painful internal derangement who show no improvement after prior nonsurgical treatment. The postoperative radiographic alterations should be interpreted as adaptive changes rather than progressive degenerative joint disease.     

Emergency Department Digital Radiology: Moving from Photos to Pixels

Emergency department (ED) patient care relies heavily on radiologic imaging. As advances in technologic innovation continue to present opportunities to streamline and simplify the delivery of care, emergency medicine (EM) practitioners face the challenge of transitioning from a system of primarily film-based radiography to one that utilizes digitized images. The move to digital radiology can result in enhanced quality of patient care, reduction of errors, and increased ED efficiency; however, making this transition will necessarily involve changes in EM practice. As the technology evolves, digital radiology will gradually become ingrained into everyday practice because of these and other notable benefits; however, EM practitioners will need to overcome several challenges to make the transition smoothly and consider the potential impacts that this change will have on ED workflow. The authors discuss the benefits, challenges, and other operational considerations involved with the ED implementation of digital radiology and close by presenting guiding principles for current and future users. Despite the unresolved issues, digital radiology will mature as a technology and improve EM practice, making it one of the great information technology advances in EM.     

Osteoplasty of the mandibular condyle with preservation of the articular soft tissue cover: comparison of fibrin sealant and sutures for fixation of the articular soft tissue cover in rabbits

Fibrin sealant and sutures were compared for fixation of the articular soft tissue cover after it had been raised in association with osteoplasty of the mandibular condyle. Nine adult rabbits were operated on bilaterally with the use of fibrin sealant on one joint and sutures on the other joint. The rabbits were killed after 3 months. Macroscopic and histologic evaluations of the condyles did not reveal any appreciable differences between the two techniques. Fibrin sealant was, however, technically easier to apply than the sutures. It was concluded that fibrin sealant might be an alternative to sutures for fixation of the articular soft tissue cover after it has been raised in association with osteoplasty of the mandibular condyle.