Diagnostic accuracy of temporomandibular joint lower-compartment arthroscopy using an ultrathin arthroscope: a postmortem study

Arthroscopy was performed on the lower temporomandibular (TMJ) joint compartment of 30 fresh cadavers using a newly developed ultrathin arthroscope. Comparison of arthroscopic and dissection findings showed a diagnostic accuracy of 57%. There were both false-positive and false-negative arthroscopic diagnosis. The majority of the false diagnosis occurred in the lateral part of the joint. Iatrogenic damage to the disc occurred in one joint. The study suggests that arthroscopy of the lower joint space of the TMJ can be done with a diagnostic accuracy similar to what has been described for the upper joint space. There appears to be no major risks of iatrogenic damage to the joint structures using an ultrathin arthroscope.     

CT density of the TMJ disk: correlation with histologic observations of hyalinization, metaplastic cartilage, and calcification in autopsy specimens.

The attenuation number of the TMJ disk was measured in direct sagittal computerized tomograms (CTs) of eight fresh TMJ autopsy specimens. The CT attenuation number was correlated to histologic observations of hyalinization, calcification, and cartilaginous metaplasia of the disk. Correlations were found between high CT attenuation numbers and the presence of hyalinization, calcification, and foci of cartilaginous metaplasia in the disks. The results suggest that the high CT attenuation number of a disk might be associated with hyalinization, calcification, and metaplastic cartilage formation.     

CT and MR of the temporomandibular joint: comparison with autopsy specimens

CT and MR imaging have been advocated for use in the diagnosis of disorders of the temporomandibular joint. A systematic comparison of these imaging techniques has not been made. We performed direct sagittal CT and sagittal MR on 15 fresh temporomandibular joint autopsy specimens and compared our diagnoses with cryosectional findings in a blinded fashion. We found no statistically significant differences between these procedures in detecting bony abnormalities or disk position. However, a side-by-side comparison between the CT and MR images demonstrated that MR depicted the soft-tissue anatomy of the joint with greater detail than did CT. Thus, MR clearly displayed the disk when it was positioned either superiorly or anteriorly, whereas CT only showed the disk adequately when it was positioned anteriorly. MR further showed the configuration of the disk and the borderlines between the disk and its attachments; these relationships could not be assessed from CT images. This experimental study indicates that MR is superior to CT for depiction of soft-tissue changes, whereas CT is superior in showing osseous abnormalities. Clinical confirmation of these results is necessary before one method can be definitively recommended over the other for clinical studies.     

Temporomandibular joint diskectomy. No positive effect of temporary silicone implant in a 5-year follow-up.

The purpose of this study was to evaluate the long-term clinical and radiologic effects of a temporary silicone implant after diskectomy of the temporomandibular joint. Forty-three temporomandibular joints in 43 patients with painful disk displacement underwent a diskectomy. A sheet of medical-grade silicone was temporarily placed in 22 patients; 21 patients did not receive an implant. The patients were clinically and radiologically examined 5 years after surgery. On the basis of symptoms and jaw function, they were classified as having good (30 patients), acceptable (8 patients), and bad (5 patients) results. All the patients with bad results and five of the eight patients with acceptable results had received implants. Erosive changes of the condyle or fossa were seen radiographically at follow-up in eight patients, each of whom had received an implant. No positive clinical or radiologic effects of the implants could be identified. The use of a temporary silicone implant after diskectomy of the temporomandibular joint in patients with internal derangement should be seriously questioned.     

Creation of disc displacement in human temporomandibular joint autopsy specimens.

The purpose of this study was to investigate the possibility of iatrogenically creating disc displacement in the human temporomandibular joint (TMJ). Fourteen fresh TMJ autopsy specimens with superior disc position were selected for the study. The upper and lower joint spaces were exposed via a preauricular incision and two to three superficial mediolateral incisions were made in the inferior surface of the posterior disc attachment (ie, retrodiscal tissue). After these incisions were made it was possible to manually displace the disc anteriorly. To maintain the disc in the anterior position the condyle was positioned against the posterior disc attachment in a manner corresponding to the closed mouth position. The joints were then fixed in this relationship and magnetic resonance imaging (MRI) was repeated using the same scanning plane and scanning parameters as before intervention. After imaging, the joints were cryosectioned to show the degree of disc displacement. Histologic analysis was made of the posterior disc attachment. Postoperative MR images and cryosections showed the disc to be displaced anteriorly in 12 of the 14 joints. Displacement of the disc was complete in eight joints (the entire mediolateral dimension of the joint) and partial (only in the lateral part of the joint) in four joints. The disc remained in a superior position in two joints. Cryosections and histologic analysis showed the incisions in the inferior aspect of the posterior disc attachment to be superficial. The results of this study suggest that the integrity of the inferior aspect of the posterior attachment of the disc to the condyle is essential for keeping the disc in its position superior to the condyle.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reliability of a negative clinical temporomandibular joint examination: prevalence of disk displacement in asymptomatic temporomandibular joints

Unilateral temporomandibular joint arthrography was performed in 40 healthy volunteers with asymptomatic and clinically normal temporomandibular joints. Thirty-four joints (85%) showed superior disk position, and six joints (15%) were radiographically abnormal with displacement of the disk. Thus, two showed anterior displacement, one showed rotational anterolateral displacement, one showed rotational anteromedial displacement, one showed sideways lateral and one showed sideways medial displacement. Thus, a negative clinical examination for temporomandibular joint internal derangements may involve a risk of being false-negative. All but one of the joints showed normalization of disk position during opening, and it is suggested that lack of functional disturbances accounts for the freedom of symptoms.