Surgical strategy for long-standing dislocation of the temporomandibular joint: experience with 16 medically compromised patients.

We evaluated the surgical outcomes in 16 patients with long-standing dislocation of the temporomandibular joint (TMJ): eight men and eight women, mean (range) age 72 (21-94) years. They all had multiple underlying diseases, either dementia or a mental disorder, and the joint had been dislocated for four weeks or longer. Manual reduction had been ineffective. They were operated on after assessments by the Department of Geriatric Medicine. The procedures were successful in 14 of the 16 patients: eminectomy (n = 5), eminectomy and discectomy or condylectomy (n = 2), eminectomy, discectomy, and condylectomy (n = 3), release of the lateral pterygoid muscle (n = 3), and curettage of a fibrotic scar in the mandibular fossa (n = 1). Reduction was "easy" (n = 4), "moderately difficult" (n = 3), or "very difficult" (n = 9). Complete reduction could not be achieved for two of the "very difficult" patients. After reduction, three patients had the mandibular condyle tethered to the mandibular fossa. Operation was successful in 12 of the 16 patients. Two patients died, one of cardiopulmonary arrest, and one of chronic pulmonary insufficiency, while reduction was incomplete in two. There were no recurrences. The difficulty of reducing the joint in most of our patients suggests that detailed preoperative surgical planning is essential, patients at risk should be carefully selected, and indications for techniques to prevent recurrence should be carefully evaluated.

A modified approach for eminectomy for temporomandibular joint dislocation under local anaesthesia: report on a series of 50 patients.

Conventional eminectomy for habitual dislocation of the temporomandibular joint is usually performed under general anaesthesia. This technique was modified for use under local anaesthesia to treat medically compromised patients. Fifty elderly patients (90 joints) were treated, for whom general anaesthesia was considered a serious risk due to systemic diseases; the dislocation was habitual in 39 and long-standing in 11. Following intravenous sedation and local anaesthesia, a 2-cm superficial vertical skin incision was made directly above the articular eminence. Careful and gentle dissection of the subcutaneous tissue was performed until the lateral joint capsule was exposed. The superior compartment was entered, followed by shaving of the articular eminence in a conventional manner. The surgery was successful in all patients, with a mean operative time of 47±12minutes. Intraoperative events occurred in 10 patients (20%). Postoperative complications affected 25 patients (50%), varying from severe (two deaths, due to cardiopulmonary arrest and accidental fall) to mild (local infection, etc.). Eleven patients (22%) had facial nerve palsy limited to the temporal branch; all recovered after 6 months. This approach is useful when general anaesthesia is contraindicated due to existing medical conditions. However, prudent consideration may be required to avoid serious complications when local anaesthesia is used.

Tethering technique using bone screws and wire for chronic mandibular dislocation: a preliminary study of refractory cases.

A retrospective study was performed to determine the efficacy of a tethering procedure developed to achieve a more rigid fixation and more reliable outcome in patients with refractory dislocation of the temporomandibular joint. The cases of eight patients with dementia and systemic diseases who underwent this technique were reviewed. In these eight patients, the condyles of 13 joints were ligated using wire between screws placed in the eminence and condylar head. Additional screw-wire ligations were applied to reinforce the restraint of movement in five of the 13 joints with suspected uncontrolled dislocation. The procedure was performed successfully, and the patients were followed-up for an average of 25months. In one patient, dislocation recurred 1year postoperatively due to wire breakage. The five joints in which a double set of screw-wire tethering was applied showed no recurrence or wire disturbance. This technique may, therefore, have short-term efficacy in cases that are refractory to standard procedures, although the material used for ligation should be investigated further. This approach can contribute to the quality of life of patients, particularly those with a short life-expectancy.

Electrophoretically separation of the synovial fluid proteins in rabbit temporomandibular arthritis induced by mechanical loading.

BACKGROUND: The concentration of protein in synovial fluid (SF) of temporomandibular joints (TMJs) with disorders tends to be increased. We investigated the protein composition of SF of rabbits in which arthritis of the TMJ was induced. METHOD: Arthritis was induced in six TMJs in six rabbits by exertion of a load for 4 weeks. Six non-loaded TMJs in six rabbits served as controls. The protein concentration and content in TMJ SF of the two groups were compared. RESULTS: The mean protein concentration was higher in the SF of the loaded group than in that of the non-loaded group (1824 microg/ml vs. 398 microg/ml, P = 0.002). Proteins with molecular weights of more than 95 kDa were abundant in the loaded group (P < 0.05). CONCLUSION: Temporomandibular arthritis induced by mechanical loading in rabbit is accompanied by an increase in the abundance of relatively high molecular weight proteins in SF.

Osteoclastogenesis inhibitory factor/osteoprotegerin in synovial fluid from patients with temporomandibular disorders.

The goal of this study was to measure the activities of osteoclastogenesis inhibitory factor/osteoprotegerin (OCIF/OPG), interleukin-1beta (IL-1beta), and tumour necrosis factor-alpha (TNF-alpha) in synovial fluid from 24 patients with internal derangement and 26 with osteoarthritis of the temporomandibular joint (TMJ). Five asymptomatic healthy volunteers were studied as control. Concentrations of OCIF/OPG, IL-1beta, and TNF-alpha were determined by enzyme-linked immunosorbent assay. The mean OCIF/OPG concentration in the patients with osteoarthritis (71 pg/ml) was significantly lower than those in the patients with internal derangement (160 pg/ml, P< 0.05) and the healthy volunteers (196 pg/ml, P< 0.01). In contrast, the IL-1beta and TNF-alpha concentrations were similar in all three groups. These results suggest that OCIF/OPG is associated with the pathogenesis of osteoarthritis of the TMJ. Perhaps, decreased OCIF/OPG concentrations promote osteoclastic activity and induce osteoarthritis of the TMJ.

Preclinical study of recombinant human bone morphogenetic protein-2: application of hyperbaric oxygenation during bone formation under unfavourable condition.

The objective of this study was to evaluate the effect of hyperbaric oxygenation on bone formation by recombinant human bone morphogenetic protein-2 (rhBMP-2) under unfavourable conditions. The calf muscles of 10 rats with low-blood supply were prepared by ligating and cutting the right femoral artery, and 10 micro of rhBMP-2 was implanted in the calf muscle. Five rats each were randomly assigned to the hyperbaric oxygenation group and the control group (untreated). The rats in the hyperbaric oxygenation group were treated with hyperbaric oxygenation at 2.0 atmospheres absolute for 3 weeks. In the histologic evaluation, the number of osteoblasts in the hyperbaric oxygenation group was greater than that in control group. The area of the trabecular bone induced in the hyperbaric oxygenation group was significantly larger than that in the control group. The values of alkaline phosphatase activity and calcium contents in the hyperbaric oxygenation group were significantly higher than those in the control group. The results of the present study suggest that hyperbaric oxygenation increases the partial oxygen pressure in low blood supply tissue and accelerates the activity and rate of osteoinduction by rhBMP-2. Hyperbaric oxygenation therapy may increase the clinical application of rhBMP-2 to unfavourable condition.

Relation between the expression of vascular endothelial growth factor in synovial tissues and the extent of joint effusion seen on magnetic resonance imaging in patients with internal derangement of the temporomandibular joint.

The aim of this study is to elucidate the relation between the expression of vascular endothelial growth factor (VEGF) in synovial tissues and the extent of joint effusion seen on magnetic resonance imaging (MRI) in patients with internal derangement of the temporomandibular joint (TMJ). Using an immunohistochemical technique, we examined specimens of synovial tissues from 41 joints in 40 patients with internal derangement. Specimens from 36 of the 41 joints stained for VEGF. There was a significant correlation between the percentage of the VEGF-stained cells and the grade of joint effusion seen on MRI (P=0.0002, r=0.62). The correlation between the two was also significant on multiple logistic regression analysis (P=0.003, odds ratio=1.75). These results suggest that VEGF may have an important role in the genesis of joint effusion.

Expression of interleukin 6 in synovial tissues in patients with internal derangement of the temporomandibular joint.

Using an immunohistochemical technique, we examined synovial tissue from 46 temporomandibular joints (TMJ) with internal derangement in 44 patients. As controls, we examined synovial tissue specimens from 7 joints with habitual dislocation without pain. In synovial tissues from 21 of the 46 joints with internal derangement, interleukin 6 (IL-6) was expressed in the synovial lining cells and in the mononuclear cells infiltrating the periphery of the blood vessels. The density of IL-6-stained cells in specimens with internal derangement correlated significantly with the grade of joint effusion shown by magnetic resonance imaging (P=0.01, r=0.32).

Correlations of the expression of fibroblast growth factor-2, vascular endothelial growth factor, and their receptors with angiogenesis in synovial tissues from patients with internal derangement of the temporomandibular joint.

Synovitis in internal derangement of the temporomandibular joint (TMJ) is accompanied by the growth of new blood vessels. Fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor (VEGF) are well-characterized angiogenic factors. The objective of this study was to elucidate the correlation between the expression of FGF-2, VEGF, and their receptors-FGF receptor-1 (FGFR-1) and VEGF receptor-1 (Flt-1)-with microvessel density in synovial tissues of the TMJ. Using an immunohistochemical technique, we examined 47 joints (45 patients) with internal derangement. Individual microvessel density was evaluated by means of the CD34 antibody, a specific endothelial marker. The correlation between the percentage of immuno-positive cells and microvessel density was evaluated. In multiple logistic regression analysis, the correlation between the percentage of Flt-1-positive cells and microvessel density was significant [p = 0.005, odds ratio = 1.071, 95% confidence interval = 1.021-1.124]. These results suggest that the expression of the VEGF/Flt-1 system is involved in angiogenesis in inflamed synovial tissue in the TMJ.

The expression of fibroblast growth factor-2 and fibroblast growth factor receptor-1 in chondrocytes in synovial chondromatosis of the temporomandibular joint. report of two cases.

Synovial chondromatosis (SC) is a rare, benign condition characterized by the formation of metaplastic cartilaginous nodules. The expression of fibroblast growth factor-2 (FGF-2) and fibroblast growth factor receptor-1 (FGFR-1) in two cases of SC of the temporomandibular joint (TMJ) were immunohistochemically studied. The possible roles of FGF-2 and FGFR-1 in SC of the TMJ are discussed.

Importance of proinflammatory cytokines in synovial fluid from 121 joints with temporomandibular disorders.

The concentrations of cytokines were measured by an ELISA in the synovial fluid from 117 patients with temporomandibular disorders (TMD) and correlated with degenerative changes of the condyle and clinical symptoms.Fifty-seven patients had degenerative changes of the condyle. The fluid from seven healthy volunteers was used as controls. The concentrations of interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and interleukin-8 (IL-8) were significantly higher in the synovial fluid of patients than controls (P<0.05). The concentration of IL-6 was significantly higher in the patients with degenerative changes than in other patients (P<0.05). The detection of IL-8 correlated with the concentrations of IL-6 and TNF-alpha. However, there was no correlation between the concentrations of any cytokines and symptoms. In conclusion, the cytokines in the synovial fluid may participate in the pathogenesis of TMD. In particular, IL-6 is important and may be associated with the development of osteoarthritis.

Regeneration of defects in the articular cartilage in rabbit temporomandibular joints by bone morphogenetic protein-2.

The purpose of this study was to investigate the therapeutic use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in internally deranged temporomandibular joints (TMJ). Defects (2 mm in diameter) were created in the surface of the condylar head. Lyophilized rhBMP-2 with collagen as the carrier was implanted in the defects in different doses: rhBMP-2 15 microg (n = 5); rhBMP-2 3 microg (n = 5); rhBMP-2 0.6 microg (n = 5). In the two control groups, the defects were either filled with collagen alone (n = 5) or left untreated (n = 5). Three weeks postoperatively the sites of defects were examined under light microscopy. In the 15 micromg and the 3 microg groups, new cartilage had filled the defects; endochondral ossification was also found deep within the defect. In the 0.6 microg group, fibrous tissue was proliferating in most areas of the defect, although cartilage was also found in some parts. In the two control groups, there was either soft tissue repair only or no evidence of tissue repair. These findings suggest that BMP-2 could stimulate the repair of defects in the articular cartilage of the mandibular condyle head during the 3 weeks postoperatively. To observe the progress of endochondral ossification in more detail, it may be necessary to extend the experiment for a longer period of time. However, this study supports the contention that BMP-2 may be useful in the regeneration of cartilage in TMJ disease.

Proinflammatory cytokines and arthroscopic findings of patients with internal derangement and osteoarthritis of the temporomandibular joint.

This study investigated the correlations between the concentrations of proinflammatory cytokines in synovial fluid and the degree of synovitis on the one hand, and the degree of degeneration of articular cartilage on the other hand, in patients with internal derangement and osteoarthritis of the temporomandibular joint. We measured the concentrations of interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha), IL-6 and IL-8 in synovial fluid and the degree of arthroscopic synovitis and degeneration of articular cartilage in 37 joints with internal derangement and osteoarthritis. The correlations between the concentration of each cytokine and the score of each arthroscopic feature were analysed statistically. The detection rates of IL-1beta,TNF-alpha, IL-6 and IL-8 were 57%, 78%, 89% and 70%, respectively. There was a positive correlation between the IL-6 concentration and the synovitis score (P = 0.02). Measurement of IL-6 in synovial fluid might be useful as an indicator of the extent of synovitis.

Importance of the changes in joint effusion shown by magnetic resonance imaging before and after arthroscopic lysis and lavage of the temporomandibular joint.

We investigated the changes in the amount of joint effusion estimated from T2-weighted magnetic resonance imaging (MRI) before and after arthroscopic lysis and lavage of the temporomandibular joint (TMJ). We studied 29 consecutive patients, each with internal derangement and osteoarthritis in one TMJ. Before operation, the MRI showed joint effusions in 22 of the patients (76%). After operation, the amount of the effusion decreased in 16 and increased in 2 patients. Effusions developed postoperatively in four of the seven patients who had no effusion before operation. In four of the six patients in whom the effusion increased, the symptoms had almost resolved by the time the MRI was taken. There was no significant correlation between changes in the amount of joint effusion and the clinical condition of the patients before and after the operation. In conclusion, changes in the amount of joint effusion in the TMJ are not related to the patient's clinical condition.

Synchronized population oscillation of excitatory synaptic potentials dependent of calcium-induced calcium release in rat neocortex layer II/III neurons.

We examined the roles played by calcium-induced calcium release from ryanodine-sensitive calcium stores in induction of neocortical membrane potential oscillation by using caffeine, an agonist of ryanodine receptors. Intracellular recordings were made from neurons in layer II/III of rat visual cortex slices in a caffeine-containing medium. White matter stimulation initially evoked monophasic synaptic potentials. As low-frequency stimulation continued for over 10 min, an oscillating synaptic potential gradually became evoked, in which a paroxysmal depolarization shift was followed by a 8-10-Hz train of several depolarizing wavelets. This oscillating potential was not induced in a medium containing no caffeine with 2 or 0.5 mM [Mg2+](o). Under blockade of N-methyl-D-aspartate receptors, induction of this oscillating potential failed even with caffeine application. Experiments with the calcium store depletor, thapsigargin, revealed that this oscillating potential is induced in a manner dependent on intracellular calcium release. Dual intracellular recordings revealed that the oscillation was synchronized in pairs of layer II/III neurons. The oscillating potential was detectable by field potential recordings also, suggesting that the present oscillation seems to reflect a network property.

Does joint effusion on T2 magnetic resonance images reflect synovitis? Comparison of arthroscopic findings in internal derangements of the temporomandibular joint.

OBJECTIVE: The purpose of this study was to clarify the characteristics of joint effusion (JE) in the temporomandibular joint by comparing T2-weighted magnetic resonance (MR) images with arthroscopic findings. STUDY DESIGN: MR images of 47 symptomatic temporomandibular joints (47 patients) with internal derangement associated with painful hypomobility were taken to evaluate the degree of JE on a scale of 0 to 3. Within 2 months after MR images, arthroscopic findings with respect to the severity of synovitis, adhesion, and degenerative change in the superior compartment were each quantitatively assessed on a scale of 0 to 10. The arthroscopic scores were compared among the 4 JE grades, as well as between 2 groups, effusion-present (grades 2 and 3) and effusion-absent (grades 0 and 1), by using the Spearman correlation coefficient and the Mann-Whitney U test. RESULTS: The distribution of JE was as follows: 10 joints had grade 0, 5 joints had grade 1, 19 joints had grade 2, and 13 joints had grade 3. The synovitis score had a significant relationship to the degree of effusion (P =.0012) and was higher in the effusion-present group (6.4 +/- 2.0) than in the effusion-absent group (4.2 +/- 1.6) (P =.0005) On the other hand, there was no statistically significant correlation between either adhesion or degenerative change and effusion. CONCLUSIONS: JE may reflect synovitis; however, the nature of JE itself needs to be further elucidated by additional studies.

Prognostic factors in arthrocentesis of the temporomandibular joint: evaluation of 100 patients with internal derangement.

PURPOSE: The goal of this study was to analyze the prognostic factors for successful arthrocentesis for internal derangement (ID) of the temporomandibular joint (TMJ). PATIENTS AND METHODS: Arthrocentesis was carried out as the initial treatment in 103 TMJs of 100 patients with ID. The effectiveness of the treatment was evaluated in terms of the postoperative range of maximal mouth opening (MMO) and the degree of preoperative pain on a visual analog scale (VAS). Prognostic factors analyzed were age, sex, duration of painful locking, preoperative and postoperative range of MMO, preoperative degree of pain, preoperative clicking on opening mouth before becoming locked, and magnetic resonance imaging (MRI) findings. These factors were statistically analyzed. RESULTS: Seventy-three cases (71%) satisfied the criteria for success. One week after the procedure, the mean range of MMO in the successful cases (43.8 +/- 5.5 mm) was significantly greater than that in unsuccessful cases (36.9 +/- 6.6 mm) (P <.05). The mean preoperative degree of pain on a VAS in successful cases (4.7 +/- 2.9) was significantly smaller than that in unsuccessful cases (6.2 +/- 2.1) (P <.05). The preoperative incidence of morphologic changes in the mandibular condyle seen on MRI of successful cases was significantly less than that in unsuccessful cases (P <.05). CONCLUSION: Severe preoperative pain, relapse in the amount of mouth opening within 1 week after arthrocentesis, and preoperative bony changes in the condyle may be predictors of the effectiveness of arthrocentesis for ID of the TMJ.

Immunohistochemical localization of bone morphogenetic protein-2 in the oral and maxillofacial area of the human embryo.

The purpose of this study was to investigate the bone morphogenetic protein-2 (BMP-2) expression in oral and maxillofacial tissue of the human embryo. A human embryo was obtained from a patient with hysterorrhexis. The oral and maxillofacial area of the embryo was analyzed immunohistochemically using specific antibodies to BMP-2. BMP-2 was found mainly localized in developing teeth buds, jaw bone, striated and smooth muscle, spinal cord and nasal tracheal and oesophagal epithelium. However, it was not found in hair follicles. These findings are similar to those of BMP-2 and -4 gene expression in mouse and rat embryos. BMP-2 may be involved in the morphogenesis of oral and maxillofacial tissue in human embryos as well as those of other animals. These results will be of considerable benefit in the restoration and regeneration of the oral and maxillofacial tissue clinically.

Accuracy of histologic grading of synovial inflammation in temporomandibular joints with internal derangement using Gynther's system.

PURPOSE: The purpose of this study was to evaluate the accuracy of the system by Gynther et al (J Oral Maxillofac Surg 56:1281, 1998) for histologic grading of synovial inflammation in the temporomandibular joint (TMJ) in arthroscopically obtained synovial biopsy specimens. PATIENT AND METHODS: Thirty-three human TMJ synovial biopsy specimens from patients with internal derangement of the TMJ were evaluated using the system of Gynther et al. The results were compared statistically with the intensity of synovitis seen arthroscopically using Spearman ranked correlation coefficient. RESULTS: In 2 of the 3 parameters tested, a statistically significant correlation was found between the histologic findings by the system of Gynther et al and arthroscopic findings using the scale of Murakami et al (J Oral Maxillofac Surg 49:1159, 1991) CONCLUSION: These results suggest that histologic grading of synovial inflammation by the system of Gynther et al has considerable accuracy. However, more investigations are necessary to confirm the results.

Analysis of 70Kd heat shock protein expression in patients with internal derangement of the temporomandibular joint.

Recent studies have demonstrated that the expression of heat shock protein (HSP) was enhanced under stress in joint diseases, such as rheumatoid arthritis and osteoarthritis. The purpose of this study was to analyze the expression of 70Kd HSP in patients with internal derangement of the temporomandibular joint (TMJ) by immunohistochemical and enzyme-linked immunosorbent assay (ELISA) methods. For immunohistochemistry, 5 extirpated discs and 16 synovial biopsy specimens from patients with TMJ internal derangement and 2 extirpated discs from normal subjects were examined. For ELISA, synovial fluid from 11 patients with TMJ internal derangement and from 6 normal volunteers were investigated. The results showed that the 70Kd HSP staining intensity in chondrocytes around the damaged area of the articular discs from patients with TMJ internal derangement was higher than that in chondrocytes in control specimens. In addition, 70Kd HSP expression in synovial fluid from patients with TMJ internal derangement was slightly higher than that in normal subjects. These findings suggest that elevated 70Kd HSP expression is related to the progression of TMJ internal derangement.