The use of pseudo-dynamic magnetic resonance imaging for evaluating the relationship between temporomandibular joint anterior disc displacement and joint pain

The relationship between temporomandibular joint (TMJ) pain and the magnetic resonance imaging (MRI) finding of articular disc displacement is debated. The purpose of this study is to investigate the correlation between TMJ pain and anterior disc displacement (ADD) using pseudo-dynamic MRI. A retrospective review of MRI studies was carried out on 130 TMJs in 65 patients presenting unilateral TMJ pain. The contralateral asymptomatic joints served as the control group. Bilateral oblique sagittal and coronal MRIs as well as pseudo-dynamic studies in the oblique sagittal plane were obtained. The disc–condyle relationship was divided into three subtypes (normal disc position, ADD with reduction, and ADD without reduction), based on the pseudo-dynamic MRI findings. Fisher's exact test was used to determine whether the TMJ pain was linked to ADD. The results showed that TMJ pain was significantly related to ADD (with and without reduction) compared to the group with a normal disc position (P = .0001). A significant correlation was found between TMJ pain and the ADD subtype without reduction, as compared to the ADD subtype with reduction (P = .0156). These data suggest that a displaced disc, particularly in the subtype without reduction, is an important source of pain.     

Diagnostic quality of dynamic high-resolution ultrasonography of the TMJ--a pilot study

The aim of this study was to compare sensitivity, specificity, accuracy and positive and negative predictive value for high-resolution ultrasonography (HR-US) in diagnosing degenerative changes, effusion and disk displacement using magnetic resonance imaging (MRI) as a reference. Over a period of 6 months, 100 patients with TMJ disorders (200 TMJs) were investigated by an experienced radiologist with HR-US and magnetic resonance imaging (MRI). The MRI investigation showed degenerative changes in 190 joints (95%), while an effusion was found in 59 (29.5%) joints. At closed-mouth position a disc dislocation was found in 138 joints (69%) and in maximum-mouth-opening position disc dislocation was diagnosed in 76 joints (38%). In the determination of degenerative changes HR-US showed a sensitivity of 94%, a specificity of 100% and an accuracy of 94%. In the detection of effusion HR-US yielded a sensitivity of 81%, a specificity of 100% and an accuracy of 95%. In the determination of disk displacement at closed-mouth position HR-US showed a sensitivity, specificity and an accuracy of 92% each. At maximum-mouth-opening position HR-US reached a sensitivity of 86%, a specificity of 91% and an accuracy of 90%. The results of the current study imply that HR-US is a valuable diagnostic imaging method of the TMJ which can be used as an alternative method to a MRI-investigation, but is yet not able to replace it. Further studies have to be done to reduce false-negative results.     

Condylar erosion and disc displacement: detection with high-resolution ultrasonography.

PURPOSE: Our goal was to determine the feasibility of high-resolution sonography for the detection of condylar erosion and associated disc displacement at the temporomandibular joint (TMJ) condyle. MATERIALS AND METHODS: Forty-eight consecutive patients (96 joints) with TMJ disorders were investigated prospectively using a 12.5-MHz array transducer. Images were assessed for condylar erosion and disc displacements. Sonographic findings were correlated with those of magnetic resonance imaging (MRI). RESULTS: At MRI, 18 osseous changes were diagnosed with condylar erosion. Sonographically, 15 of the 18 condylar erosions were diagnosed correctly. Sensitivity, specificity, and accuracy of sonography in the depiction of condylar erosion were 83%, 63%, and 67%, respectively. The positive predictive value was 34%, and the negative predictive value was 94%. Disc displacement without reduction (43 of 96) and disc displacement without reduction concomitant with condylar erosion (16 of 96) were detected with an accuracy of 93% and 80%. CONCLUSION: Sonography is an insufficient imaging technique for the detection of condylar erosion. Assessment of disc displacement without reduction may be reliably made with sonography.     

High-resolution ultrasonography of the TMJ: helpful diagnostic approach for patients with TMJ disorders ?

PURPOSE: The purpose of this study was to investigate patients with a clinical diagnosis of internal derangement to determine the diagnostic value of static high resolution ultrasonography (HR-US) when compared with magnetic resonance imaging (MRI). PATIENTS: Sixty-six patients (132 temporomandibular joints [TMJs]) with a clinical diagnosis of internal derangement were investigated by HR-US and MRI. METHODS: MRI and HR-US investigations were performed by experienced radiologists. The sonograms were done with a real-time 12-Mhz linear-array scanner. The HR-US interpretation errors were re-evaluated retrospectively by the same radiologist knowing the MRI results by comparing these with the 'prospective' and 'retrospective' diagnoses. The prospective and retrospective diagnoses were also compared with each other. RESULTS: Eighty-seven of the 132 TMJs had a disc displacement proved by MRI in the closed-mouth position. At maximum mouth opening, 54 TMJs had a disc displacement. The prospective interpretations showed a sensitivity and specificity of 78% each, accounting for an accuracy of 78%. At maximum mouth opening, HR-US resulted in a sensitivity of 61%, a specificity of 88% and an accuracy of 77%. The retrospective interpretations yielded a sensitivity of 90%, a specificity of 84% and an accuracy of 88% in the closed-mouth position. At maximum mouth opening, HR-US showed a sensitivity of 73%, a specificity of 95% and an accuracy of 86%. CONCLUSION: HR-US is suitable for the detection of disc displacements in the TMJ. However, further studies may be warranted to reduce the proportion of false-positive interpretations, thereby avoiding the application of unnecessary treatment.     

Validity of functional diagnostic examination for temporomandibular joint disc displacement with reduction

The choice of approach for diagnosing temporomandibular joint (TMJ) anterior disc displacement with reduction (ADDR), viz. functional examination or TMJ imaging, is debatable and complicated by findings of low agreement between these approaches. Our aim was to investigate the validity of functional ADDR diagnostics using clinical examination and opto‐electronic mandibular movement recordings versus magnetic resonance imaging (MRI). 53 participants (32 women and 21 men, mean age ± s.d. of 28·7 ± 10·1 years) underwent a clinical examination, mandibular movement recording and MRI of their TMJs within 1 month. All were performed and analysed in a single‐blind design by different experienced examiners for each technique. The sensitivity and specificity of each functional diagnostic method was calculated, with MRI as the gold standard. Anterior disc displacement with reduction was diagnosed in 27·6% of the TMJs clinically, in 15·2% using the movement recordings and in 44·8% on MRI. The specificity of the clinical examination for diagnosing ADDR was 81·0%, and of the movement recordings, 96·6%. The sensitivity was 38·3% and 29·8%, respectively. The chance of having a false‐positive functional diagnosis of ADDR compared with MRI is low, and disagreement between the functional methods and MRI is mainly due to the high number of MRI diagnoses in asymptomatic subjects. In view of the fact that ADDR becomes clinically relevant only when it interferes with TMJ function, the functional diagnostic approach can be considered benchmark in ADDR recognition.     

MRI evaluation of the classification,frequency, and disc morphology of temporomandibular joint disc displacements: a multicenter retrospective study in a Turkish population

Objectives  Magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) and temporomandibular disorders (TMDs) have been discussed in detail for various populations. As no such study has examined the Turkish population, we determined the frequency of TMDs in the Turkish population through a multicentric investigation using MRI. Methods  This retrospective study examined 504 TMJs of 252 symptomatic patients who had undergone bilateral MRI investigation in four different dental schools. The image analysis included the assessment of disc position and morphology, and recaptured the coronal and sagittal planes in the closed and open mouth positions. The TMJ disorders were classified using the Clinical Diagnostic Criteria for Temporomandibular Disorders (CDC/TMD). The correlations among the groups of TMJs and disc morphologies were analyzed statistically using the chi-square test (P ≤ 0.05). Results  Disc displacement and abnormal disc morphology were detected in 69.5% of the symptomatic TMJ patients. Of the joints examined using MRI, 154 were normal, 135 had anterior disc displacement with reduction (ADDwR), 145 had anterior disc displacement without reduction (ADDwoR), 30 had partial anterior disc displacement, and 18 had sideways disc displacements. Regarding disc morphology, enlargement in the posterior band was the most commonly encountered type and was observed in 152 TMJs. Overall, the average time for referral for treatment, which was defined as the time from symptom onset until the time of referral, was 1.5 years. Conclusions  The most common type of disc displacement found in the Turkish population studied was ADDwoR. In addition, patients did not perceive the symptoms of TMDs as a disease and did not seek help until the TMJ derangement caused a major complaint.     

Are high-resolution ultrasonographic signs of disc displacement valid?

PURPOSE: The study goal was to define the positive predictive value (PPV) for the diagnosis of disc displacement of the temporomandibular joint (TMJ) with the use of high-resolution ultrasonography (HR-US). MATERIALS AND METHODS: The HR-US reports for 29 patients aged 19 to 62 years who had a prospective clinical diagnosis of TMJ internal derangement were correlated with magnetic resonance results. RESULTS: For the prospective HR-US interpretation, the PPV for disc displacement was 97% at the closed-mouth position and 88% at the maximum-mouth opening position. CONCLUSION: The PPV for the HR-US diagnosis of disc displacement is high.     

The effect of arthroscopic disc repositioning on facial growth in juvenile patients with unilateral anterior disc displacement

ObjectiveTo investigate the effect of arthroscopic disc repositioning on condylar development and mandibular asymmetry in juvenile patients with unilateral temporomandibular joint (TMJ) anterior disc displacement (ADD).Patients and methodsA retrospective cohort study was conducted on unilateral juvenile anterior disc displacement (UJADD) patients of 10–20 years of age treated in Shanghai Ninth People's Hospital from 2010 to 2017. The primary predictor was TMJ arthroscopic disc repositioning surgery, according to which patients were divided into a surgery group and a control group. Initial and re-examined (with at least 6-month interval) magnetic resonance imaging (MRI) and posteroanterior cephalometric radiographs (PA) were collected. The condylar heights on both sides of the TMJ were measured by MRI and the difference between them was calculated. Menton (Me) deviation was measured based on PA. Changes in condylar height difference and Me deviation were compared between the two groups.ResultsA total of 108 UJADD patients were collected in this study, including 55 patients in the surgery group and 53 patients in the control group. There were no significant differences in age, sex and follow-up time between the two groups. The condylar height difference was (−0.61 ± 2.02) mm in surgery group and (1.68 ± 1.73) mm in control group (P < 0.0001); while the Me deviation was (−1.00 ± 1.15) mm in surgery group and (1.81 ± 1.96) mm in control group (P < 0.0001), indicating that TMJ arthroscopic disc repositioning surgery could significantly improve condylar height difference and Me deviation.ConclusionsUJADD should be treated as early as possible, especially in juvenile patients, in order to improve condylar development and avoid jaw deformities.     

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??Objective??To evaluate the stability of disc position and condylar status by magnetic resonance imaging ??MRI??after temporomandibular joint ??TMJ??disc repositioning surgery with miniscrew anchor technique. Methods??Totally 150 cases of patients diagnosed with anterior disc displacement ??ADD??who received disc repositioning ??210 joints??were selected from February 2009 to July 2017 in the Department of Oral Surgery??Ninth People’s Hospital??Shanghai Jiao Tong University School of Medicine. MRIs within 1 week after operation and during at least 1 year follow-up were used to evaluate changes in the disc position and condylar bone. During follow-up??ADD without reduction was considered relapse and the bone status was classified as regeneration or degeneration. Results??Postoperative MRIs showed that all the discs were repositioned. During 12 to 96 months of follow-up ??averaged 26.73 months????95.71%??201/210?? of the discs  were still in position??whereas 5.71%??12/210?? of the discs  had relapsed anteriorly. Condylar new bone formation was observed in 77.62% ??163/210?? of the joints??no bone change in 20.48% ??43/210?? of the joints??and bone resorption in 1.90% ??4/210?? of the joints. Conclusion??TMJ disc repositioning by miniscrew anchor provides an effective means for the treatment of anterior disc displacement with stable result. Disc repositioin can also stimulate condylar bone regeneration.     

关节盘复位锚固术术后稳定性的影像学评价

目的　通过MRI评价颞下颌关节盘复位锚固术术后稳定性及髁突的改建情况。方法　选择2009年2月至2017年7月在上海交通大学医学院附属第九人民医院口腔外科行关节盘复位锚固术的150例颞下颌关节盘前移位（anterior disc displacement,ADD）患者（210侧关节）。经术后1周和至少1年MRI随访,评估关节盘的位置和髁突骨质变化。随访期间若出现不可复性ADD,则认为术后复发,根据骨质状态,将髁突改变分为再生或吸收。结果　术后1周MRI显示所有移位关节盘均复位。经12～96个月（平均26.73 个月）的随访,MRI显示95.71%（201/210）的关节盘位置良好,而5.71%（12/210）的关节盘前移复发。77.62%（163/210）的髁突有新骨形成,20.48%（43/210）的髁突无骨质变化,1.90%（4/210）的髁突发生骨吸收。结论　关节盘复位锚固术是治疗ADD的有效手段,盘复位位置稳定,并能刺激髁突骨再生。     

Sonography of the temporomandibular joint from 60 examinations and comparison with MRI and axiography

BACKGROUND AND OBJECTIVE: Establishing a diagnosis of temporomandibular joint disorder is mainly based on clinical assessment, functional examination, nuclear magnetic resonance imaging (MRI) and axiography. Sonographic examination was compared with MRI and axiography in assessing temporomandibular joint (TMJ) function in 55 patients. PATIENTS AND METHODS: Fifty-five patients with different TMJ problems were examined clinically, by means of axiography, sonography and some also by MRI. The range of motion was measured by sonography and axiography and the results compared using Student's t-test. Anatomical details diagnostic for disc-displacement were tested by sonography and MRI. RESULTS: The average time required for sonography was 2 min and for axiography 20 min. The mean measurement differences for condylar movement in maximal mouth opening was 1.7 mm, for protrusion 1.6 mm and for mediotrusion 2.5 mm. The range of condylar movement as measured by sonography and axiography coincided for opening and for protrusion (statistically significant). No significance was found for lateral excursions. The concordance in diagnosis of disc dislocation, hypermobility and impaired range of motion when comparing ultrasound with MRI was 83%. All sonographic examinations were performed by one person only. Sixty repeat examinations in patients produced no complaints and showed an absolute range of difference of 0.6 mm, with a relative range of 7%. Student's t-test was significant (p<0.05) (two repetitive measurements). CONCLUSION: Sonography proved to be a fast and reliable method for evaluating the range of movement of the TMJ. The lateral joint capsule, lateral disc, and upper condyle could be demonstrated. Pathological processes such as anterior or lateral disc displacement, disc perforation, seroma following contusion, capsular fibrosis, crystalline structures in the synovia and fracture dislocation of the condyle could be diagnosed with considerable reliability when compared with MRI. However, the medial aspect of the joint, medial disc dislocation and the angulation of the condylar slope could not be seen.     

SPECT/CT研究颞颌关节盘移位对髁突骨代谢的影响

目的利用单光子发射型计算机体层摄影（SPECT/CT）骨显像技术研究颞下颌关节盘前移位（ADD）患者髁突骨代谢变化,探讨盘移位时间及程度对髁突骨代谢影响规律。 方法选取临床及磁共振成像（MRI）检查确诊为单侧颞下颌关节盘前移位患者130例,纳入病例均接受颞下颌关节SPECT/CT检查,对健患侧感兴趣区（ROI）核素计数值与病程及关节盘移位分期进行配对检验及相关性分析。 结果SPECT/CT检查患侧髁突延迟相异常浓聚阳性率为86.92%（113/130）,研究对象健侧（22,13）与患侧ROI计数（26,15）的差异有统计学意义（Z = 8.909,P<0.001）,患侧ROI计数与盘移位时间呈负相关（r = -0.332,P<0.001）。 结论通过SPECT/CT研究得出,随颞下颌关节盘移位时间的推移,ADD髁突成骨性活动降低。     

关节盘锚固术联合正畸功能性矫治器治疗青少年双侧颞下颌关节盘前移位伴骨性Ⅱ类错牙合畸形临床效果评价

目的　评价关节盘锚固术联合正畸功能性矫治器治疗青少年双侧颞下颌关节盘前移位伴骨性Ⅱ类错牙合畸形的临床效果。方法　选取2016年3月至2018年3月上海交通大学医学院附属第九人民医院口腔外科收治的青少年双侧颞下颌关节盘前移位伴骨性Ⅱ类错牙合畸形患者14例（28侧关节）,收集患者术前及术后随访期间的颞下颌关节MRI和头颅侧位片,对患者术前及术后随访期间的髁突高度及相关头影指标进行测量,比较手术前后的差异并进行统计学分析。结果　MRI测量显示：术后随访髁突高度比术前平均增加（1.74 ± 0.98）mm（P＜0.001）。28侧髁突均有新骨形成,主要位于髁突的顶端和前后缘（占84.61%）。头影指标测量显示：由蝶鞍中心、鼻根点及上齿槽座点所构成的角（SNA角）、软组织鼻根点到经额点且垂直于前颅底平面直线的垂直距离（Sn-G）、Y轴角（Y-Axis）、上中切牙-前颅底平面角（U1-SN）、下中切牙-下颌平面角（L1-MP）及上下中切牙角（U1-L1）手术前后差异无统计学意义;而由蝶鞍中心、鼻根点及下齿槽座点所构成的角（SNB角）比术前增加（1.83±1.56）°（P＜0.001）,下颌颏前点（Gn）术后前移（2.18 ± 3.13）mm（P = 0.028）,前牙覆盖（overjet）比术前平均缩小（3.55 ± 1.86）mm（P＜0.001）。结论　关节盘锚固联合术后正畸功能性矫治器治疗青少年颞下颌关节盘前移位伴骨性Ⅱ类错牙合畸形,可以促进其髁突生长,减轻牙颌面畸形的程度。     

Error patterns and observer variations in the high-resolution ultrasonography imaging evaluation of the disk position of the temporomandibular joint

OBJECTIVES. The purpose of this study was (1) to describe errors in the interpretation of high-resolution ultrasonography (HR-US) images of the temporomandibular joint (TMJ) and analyze the discrepancies between HR-US imaging and diagnostic magnetic resonance imaging findings, and (2) to measure interobserver and intraobserver variations with respect to reporting HR-US images of the TMJ. STUDY DESIGN. The sonographic reports of 208 patients aged 13 to 78 years who had a prospective clinical diagnosis of TMJ internal derangement were correlated with magnetic resonance imaging results. Prospective and retrospective readings were used to classify types of disk displacement. Assessment of observer variation was based on a set of 200 HR-US images in 50 randomly selected patients. The images were interpreted independently by 2 trained radiologists at 2 sessions, 1 to 2 weeks apart. RESULTS. Prospective interpretation of TMJ HR-US images at the closed-mouth position had a sensitivity of 80%, specificity of 87%, and accuracy of 82%. For images at the maximum mouth-opening position, the sensitivity was 68%, specificity 93%, and accuracy 82%. The number of diagnostic errors at retrospective analysis was 60.3% (n = 73) of the number at prospective analysis. The intraobserver agreement for reporting the disk position at the closed-mouth position was 93% and at the maximum mouth-opening position was 88%. The agreement between the 2 observers was 89% on the position of the disk at the closed-mouth position and 84% at the maximum mouth-opening position. CONCLUSIONS. The high diagnostic accuracy, together with the low observer variation reported in this study, suggest that HR-US of the TMJ is a valuable imaging technique for assessment of disk displacement. Many errors that occur at prospective analysis didn't occur at retrospective analysis.     

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??Objective??To evaluate the effect of articular disc repositioning combined with orthodontic functional appliance in the treatment of juvenile bilateral temporomandibular joint ??TMJ??anterior disc displacement??ADD?? and  skeletal class ??malocclusion. Methods??Fourteen juvenile patients with bilateral TMJ ADD and skeletal class ?? malocclusion were selected from March 2016 to March 2018 in the Department of Oral Surgery??Ninth People’s Hospital??Shanghai Jiao Tong University School of Medicine. Magnetic resonance imaging ??MRI?? and cephalometric radiographs before surgery and  follow-ups were performed for all patients. Condylar height and relevant cephalometric radiographs were measured and compared by statistical analysis. Results??Compared with pre-surgery??MRI showed the condylar height increased ??1.74±0.98??mm during follow-ups after surgery ??P??0.001??. New generated bone was observed on all condyles. About 84.61% of the new bone formed at superior and posterior-anterior surface. Cephalometric radiographs showed that SNB increased ??1.83±1.56??°??P??0.001????pogonion position ??pog-G?? moved ??2.18±3.13??mm ??P = 0.028?? forward and incisor overjet decreased ??3.55 ± 1.86??mm ??P??0.001????whereas no significant changes were found in SNA??Sn - G Vert??Y-Axis??U1 - SN??IMPA ??L1-MP?? or U1-L1 ??P > 0.05??. Conclusion??Articular disc repositioning combined with postoperative orthodontic functional appliances can effectively promote condylar growth and reduce oral-maxillofacial deformities in juvenile patients with bilateral  TMJ ADD and skeletal class??malocclusion.     

The evaluation of temporomandibular joint disc position in TMJ disorders using MRI

The purpose of this study was to correlate disc position and the type of disc displacement, intra-capsular effusion and degenerative changes of the condyle as demonstrated in MRI studies. In this study, 126 temporomandibular joints (TMJs) of 63 patients with TMJ disorders were investigated using clinical examination and MRI. One hundred and twelve TMJs were found to have internal derangement as disc displacement. The angle between the posterior margin of the disc and the vertical line drawn through the centre of the condyle was measured on MRI for each TMJ. The positions of the discs were normal, 0 degrees-10 degrees, in 11.11%; slightly displaced, 11 degrees-30 degrees, in 37.30%; mildly displaced 31 degrees-50 degrees, in 15.08%; moderately displaced, 51 degrees-80 degrees, in 7.14% of the TMJs with anterior displacement with reduction (ADDR). The disc position was severely displaced anteriorly, as over 80 degrees, in all TMJs with anterior disc displacement without reduction (ADD), constituting 27.78% of all cases. We found that the smaller the degree of disc displacement the milder the internal derangement and that the intra-capsular effusion was more frequently associated with TMJ with ADDR. The degenerative condylar changes were more severe with an increased degree of anterior disc displacement.     

Magnetic resonance imaging assessment of temporomandibular joint soft tissue injuries of intracapsular condylar fracture

We evaluated the soft tissue of the temporomandibular joint (TMJ) with magnetic resonance imaging (MRI) after intracapsular condylar fracture. Eighteen consecutive patients (19 TMJ) were diagnosed between 1 January 2010 and 30 October 2011. They were examined using bilateral sagittal and coronal MRI, which were obtained immediately after injury to assess the displacement of the disc, whether there was a tear in capsule or the retrodiscal tissue, and whether there was an effusion in the joint. On the affected side MRI showed disc displacement in 15 of 19, tears in the capsule in 9, and tears in the retrodiscal tissue in 16. All 19 had joint effusions. It also showed 2 joints with abnormalities on the unaffected side. We conclude that MRI is useful for diagnosis and for estimating the amount of damage to the TMJ, and is helpful in planning treatment.     

Correlation between direction and severity of temporomandibular joint disc displacement and reduction ability during mouth opening

The most common temporomandibular joint (TMJ) internal derangement is an abnormal relationship of the disc with respect to the mandibular condyle, articular eminence and glenoid fossa‐disc displacement. The aim of our study was to analyse the correlation between partial/complete disc displacement in the intercuspal position (IP) and its reduction in the open‐mouth position (OMP) in both oblique sagittal and coronal planes on magnetic resonance imaging (MRI) in patients with temporomandibular disorders. Multisection MRI analysis of 382 TMJs was conducted in 191 patients with disc displacement according to the RDC/TMD criteria (148 women, 43 men; aged 14‐60 years). The disc position was evaluated on all oblique sagittal and coronal images in the IP and the OMP. Univariate logistic regression analysis showed that the severity of disc displacement in the sagittal plane is a statistically significant predictor of reduction ability during mouth opening (B = 3.118; P < .001). Moreover, the severity of disc displacement in both planes is also a significant predictor of disc reduction in OMP (B = 2.200; P < .05). In conclusion, reduction ability during mouth opening is associated with the severity of disc displacement in IP, in both sagittal and coronal planes. Multisection analysis of all MR images allows distinguishing the correct disc position from disc displacement and can improve the ability to distinguish between various stages of TMJ internal derangement.     

Clinical protocol for managing acute disc displacement without reduction: a magnetic resonance imaging evaluation

This study investigated the efficacy of a sequential combination of arthrocentesis, mandibular manipulation, and anterior repositioning splint (ARS) in the management of acute temporomandibular joint (TMJ) disc displacement without reduction (DDwoR). Twenty-one consecutive patients diagnosed with acute DDwoR by Diagnostic Criteria for Temporomandibular Disorders and magnetic resonance imaging (MRI) were recruited and managed with this method. Clinical and MRI data were obtained before and at 1 week after treatment. The disc–condyle relationship was determined by disc–condyle angle measurement. Condyle/disc positions were described as x–y coordinates with the summit of the articular fossa as the coordinate origin. Statistical analyses including independent/paired samples t-tests were conducted; significance was set at P < 0.05. Clinical success was observed in 95.2% of patients (20/21) with 22 joints affected by acute DDwoR. After combined treatment and ARS insertion, TMJs with DDwoR showed (a) normal disc–condyle relationships with substantial forward and downward condyle movement and significant disc reduction in closed position, and (b) discs with an intermediate zone located between the condylar head and articular eminence in open position. The combined approach was highly effective in ‘unlocking’ acute TMJ DDwoR and achieving spatial full disc reduction and a normal disc–condyle relationship. The duration of acute DDwoR appears to be critical for success.     

改良耳屏切口颞下颌关节盘复位固定术手术入路介绍及效果评价

目的: 介绍一种改良耳屏切口颞下颌关节盘复位固定术术式并初步评价其临床效果。方法: 选取符合条件的颞下颌关节盘不可复性前移位患者6例（7侧关节）,依据Wilkes-Bronstein分期,纳入IV~V期患者,采用改良耳屏切口行颞下颌关节盘复位固定术。结果: 术中术区视野显露充分,术后MRI显示全部7侧关节盘复位良好,面神经功能保存良好。结论: 经改良耳屏切口行颞下颌关节盘复位固定术,术中暴露关节区充分,术后短期疗效可靠,且具有切口美观,手术创伤小,面神经受损程度轻等优点。可作为颞下颌关节手术的入路之一。