Temporomandibular joint: variation of normal arthrographic anatomy

The arthrograms of 34 individuals with asymptomatic, clinically and arthrographically normal temporomandibular joints were analyzed. The results showed a substantial variation of the dimensions and configuration of the joint compartments. Thus the anterior recess of the lower joint compartment was small in 15 joints (44%), medium-size in 16 joints (47%), and large in three joints (9%). The upper margin of this recess was flat or convex in 24 joints (71%) and concave in 10 joints (29%). These observations contradict previous assumptions about a strict association between the configuration and dimension of the anterior recess of the lower joint compartment and the position of the disk. It was concluded that dimension and configuration of the joint compartments should not be used as the only criteria for diagnosis of the position of the disk.

High condylar shave of the temporomandibular joint with preservation of the articular soft tissue cover: an experimental study on rabbits

The high condylar shave has the disadvantage of removing the articular soft tissue cover together with the underlying condylar bone. In an attempt to overcome this disadvantage, we elevated the articular soft tissue cover, shaved the condylar head, and replaced the articular soft tissue cover in its original position in nine adult rabbit temporomandibular joints. On the contralateral joints, the same amount of bone was shaved together with the articular soft tissue cover. The rabbits were killed after 3 months, and the condyles were macroscopically and histologically evaluated. All condyles were covered with an articular soft tissue layer in the area operated on. This surface was smoother when the articular soft tissue cover was preserved. Histologically, the subarticular layer of cartilage cells was continuous in the joints with preservation of the articular soft tissue cover but was frequently interrupted in the joints where this cover was removed. The incision made in the posterior part of the articular surface for elevating the articular soft tissue cover frequently caused a deformity of the condyle and an interruption of the subarticular layer of cartilage. The results suggest that preservation of the articular soft tissue cover on the mandibular condyle might be one way to improve the postoperative morphology after high condylar shave. The technique in its present state has obvious drawbacks and should be further refined before it is considered for clinical application.

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.

Cryosectional observations of functional anatomy of the temporomandibular joint

The anatomy and function of the temporomandibular joint are complex, and our understanding about how the retrocondylar tissues change when the condyle translates anteriorly has been incomplete. We therefore examined the sectional anatomy of 24 fresh human temporomandibular joints at different gradations of jaw opening, protrusion, and laterotrusion. We found that the tissues of the posterior disk attachment expanded in volume and occupied the space behind the condyle when the mouth was opened, protruded, or laterotruded to the contralateral side. Volumetric expansion of the tissue seemed to be due mainly to distension of the venous structures in the retrodiskal area. In the lateral region of the joint, tissue from the superior aspect of the parotid gland also seemed to contribute to the filling of the space posterior to the condyle. Thus, the retrodiskal tissue appears to have a substantial capacity to expand and fill the mandibular fossa when the condyle translates anteriorly. The possibility of a dynamic vascular physiology is suggested.

Arthroscopic diagnosis of perforation and adhesions of the temporomandibular joint: correlation with postmortem morphology

Arthoscopy was performed in the upper joint compartment of 28 temporomandibular joints in 16 fresh cadavers to investigate the accuracy of arthroscopic diagnoses of perforation and adhesion. Subsequent dissections revealed that only three of nine perforations were seen arthroscopically and that three of four joints with adhesions were arthroscopically diagnosed. There was no overdiagnosis of perforation or adhesions. Intra-articular hyperplastic soft tissue formation (crab meat) was arthroscopically seen in ten joints (36%) and was with only two exceptions associated with either a perforation or adhesions. Histologically, the adhesion and the hyperplastic soft tissue consisted of fibrous connective tissue with collagen fibers and fibroblasts. It was concluded that a positive arthroscopic diagnosis of adhesion or perforation is reliable whereas a negative diagnosis of perforation is not reliable.

MR imaging of the temporomandibular joint: comparison of images of autopsy specimens made at 0.3 T and 1.5 T with anatomic cryosections

We made MR images of 39 autopsy specimens of the temporomandibular joint at 0.3 and 1.5 T and compared the images with anatomic cryosections. Imaging time and slice thickness were the same on scans made at each field strength. The purpose was to determine which field strength provides the best scans for imaging of the joint. Additionally, we used imaging times two and four times longer on the 0.3-T scanner to assess to what extent image quality and diagnostic accuracy could be improved. The cryosections showed that 27 of the joints were normal. Twelve had disk displacements. Ten of the joints with disk displacement also had disk deformities, and seven had bony abnormalities. Investigators who analyzed the MR images had no knowledge of the findings on the cryosections. The disk position, disk configuration, and bony abnormalities were correctly diagnosed in 85%, 77%, and 100%, respectively, on 1.5-T MR images compared with 46%, 41%, and 85%, respectively, on the 0.3-T images. When the imaging time was increased by a factor of four, the accuracy rate on the 0.3-T system became comparable to that of the 1.5-T MR scanner: 73% for disk position, 67% for disk configuration. The results suggest that the diagnostic quality of MR images of the temporomandibular joint is better on scans made at 1.5 T than on those done at 0.3 T when comparable imaging times are used.

Histologic features of the temporomandibular joint disk and posterior disk attachment: comparison of symptom-free persons with normally positioned disks and patients with internal derangement

To gain further knowledge about the differences between normal and pathologic anatomy of the temporomandibular joint disk, we examined histologically disks obtained at autopsy from 10 symptom-free persons and compared our findings with observations involving 17 surgically removed disks. The surgical patients had internal derangement and severe long-standing temporomandibular joint pain and dysfunction. The normal disks were biconcave, whereas the surgically removed disks were deformed and thicker than the normal disks. Chondrocytes (4 joints), a surface layer of proliferative connective tissue (4 joints), vessels (2 joints), and splitting (4 joints) were seen in the surgical specimens but not in the normal specimens. The surgical specimens also showed higher maximal density of fibroblasts and vessels. It was concluded that surgically removed temporomandibular joint disks demonstrated several histologic alterations that were not seen in normal disks. These characteristics may serve as the basis for development of a histologic grading of pathologic conditions of the temporomandibular joint disk and the posterior disk attachment.

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.

A case of giant mediastinal leiomyoma with long-term survival

A 67-year-old female was emergently admitted to our hospital because of severe dyspnea with cyanosis. One month before admission, she consulted a doctor and chest x-ray disclosed a huge tumor shadow occupying most of the left hemithorax. At that time, she did not complain of any particular symptoms except slight cough. Twelve days after admission, the patient lost consciousness and an emergency operation was performed. The tumor showed severe adhesion to the aorta and the lower lobe of the left lung, but not to the esophagus. After the operation, mechanical ventilation was necessary for 13 days to recover pulmonary function. Histological diagnosis was made as leiomyoma, which is rarely seen in the mediastinal region. At present, the patient survived 10 years without any symptom of recurrence. In this paper, the authors report a case of mediastinal leiomyoma which received an emergency operation and attained long term survival. Twelve similar cases reported in the past were also reviewed.

[Arterial infusion chemotherapy and embolization in unresectable hepatocellular carcinoma using an intraarterial catheter]

We performed arterial infusion chemotherapy and embolization on 22 patients with unresectable hepatocellular carcinoma via an intraarterial catheter, which was inserted in the hepatic artery under laparotomy. The administration frequency of intraarterial chemotherapy on a patient was 1 to 155 with a median of 17, while that of embolization was 1 to 6 with a median of 2.5. The maximal and average durations of a catheter in place were 15 and 4 months, respectively. The survival rates were 50% in one year, 18% in two years, and 12% in three years. Insertion technique and management of the catheter are relatively safe and easy, so catheterization of the hepatic artery would enable us to develop new treatment modalities.