髁突骨软骨瘤与髁突增生患者的CT表现特点分析

目的:比较下颌骨髁突骨软骨瘤和单侧下颌骨髁突增生的CT表现特点。方法:对2005—2010年上海交通大学医学院附属第九人民医院口腔颌面外科收治的下颌骨髁突骨软骨瘤11例和单侧下颌骨髁突增生8例患者的CT影像学资料进行评价,评价指标包括病变髁突大小、病变范围以及病变周围软硬组织改变。结果:11例下颌骨髁突骨软骨瘤病例CT显示肿瘤与病变髁突无明显分界(8/11)或与患侧髁突有蒂相连(3/11);肿瘤骨皮质及骨髓腔均与患侧髁突相续,瘤体表面均有特征性薄层软骨帽覆盖,瘤体外周密度通常高于中心;瘤体周围均有薄层软组织包绕。患侧颞骨关节面表面均有明显矿化,且因受瘤体压迫改建而较对侧平坦,患侧关节上、下腔间隙较对侧明显变窄;肿瘤生长方向不尽相同。8例单侧下颌骨髁突增生病例CT显示髁突颈部和(或)下颌支延长,髁突形状改变;增生的髁突外周骨皮质均有不同程度的骨化,硬化层厚度较对侧大;骨髓腔密度较不均匀。结论:CT检查能有效提供病变髁突及其周围软硬组织情况,为鉴别诊断下颌骨髁突骨软骨瘤和单侧下颌骨髁突增生提供良好的依据。     

放射性核素骨扫描技术在髁突肥大的诊断和治疗中的应用

髁突肥大治疗计划的制定往往依据于对髁突的生长情况的诊断.放射性核素骨扫描作为一种相对于临床检查和传统影像学判断更为精准灵敏的技术,可为髁突肥大治疗计划的制定提供依据和指导.因此,国内外学者对放射性核素骨扫描技术的原理和方法 、其在髁突肥大诊断与治疗中的作用、其测量值于髁突肥大治疗计划制定中的指导意义和与临床诊断方法 的优劣比较等作了大量相关的研究.下面就近年来国内外学者对该技术的研究成果作一.     

Micro-computed tomography evaluation of bone architecture in various forms of unilateral condylar hyperplasia

Condylar hyperplasia is one of the causes of facial asymmetry and malocclusion, characterized by enlargement of the lower jaw due to excessive condyle growth activity. The aim of this study was to use micro-computed tomography (micro-CT) to evaluate the bone architecture of the condylar head and determine whether there are differences between patients with various forms of unilateral condylar hyperplasia (UCH): hemimandibular hyperplasia, elongation, and mixed form. The cohort consisted of 28 patients with a mean age of 21.9 years. All patients underwent surgical treatment (condylar shaving) for active pathological growth activity. The portion of the condylar head removed was imaged by micro-CT and subsequently evaluated. Micro-CT imaging and semiquantitative and quantitative evaluation of the bone structure (percentage bone volume, surface density, trabecular thickness, trabecular separation, degree of anisotropy, and porosity of the subchondral bone) did not reveal significant differences between the individual types of condylar hyperplasia (P > 0.05). There were no significant differences in bone structure between the anterior and posterior portions of the condylar head. No statistically significant differences between individual groups of UCH were found in the micro-CT evaluation of the condylar head bone architecture.     

Condyle and mandibular bone change after unilateral condylar neck fracture in growing rats

Unilateral fracture of the condylar neck in immature subjects might lead to mandible asymmetry and condyle remodelling. A rat model was used to investigate mandibular deviation and condylar remodelling associated with condyle fracture. 72 4-week-old male rats were randomly divided into three groups: an experimental group (unilateral transverse condylar fracture induced surgically), a sham operation group (surgical exposure but no fracture), and a non-operative control group (no operation). The rats were killed at intervals up to 9weeks after surgery, and outcomes were assessed using various measures of mandible deviation, histological and X-ray observation, and immunohistochemical measures of expression levels of connective tissue growth factor (CTGF) and type II collagen (Col II). The fracture led to the degeneration of mandibular size, associated with atrophy of fractured condylar process. Progressive remodelling of cartilage and increasing expression levels of CTGF and Col II were found. The authors conclude that condylar fracture can lead to asymmetries in mandible and condyle remodelling and expression of CTGF and Col II in condylar cartilage on both the ipsilateral and the contralateral sides.     

Histological evaluation of condylar hyperplasia model of rabbit following distraction osteogenesis of the condylar neck

Summary Condylar hyperplasia is the excessive unilateral growth of mandibular leading to facial asymmetry, occlusal disturbance, joint pain and dysfunction. The aim of this study is to evaluate the histological presence of temporomandibular joint in model of condylar hyperplasia by lengthening unilateral condylar neck of distraction osteogenesis. An extra oral distractor was employed to achieve unilateral condylar neck distraction (1·0 mm daily for 7 days). The experimental condylar necks were elongated by 7 mm compared to the contralateral. Eleven adult white rabbits were used. Eight rabbits were, respectively, sacrificed after the post‐distraction period (4 or 8 weeks). All animals were evaluated clinically and histomorphometrically. The condyles radiologically showed remodelling, flattening and sclerosis. In 4‐week group, thinning of the cartilage was evident, and the trabeculae were long, not multiply connected. A thin, dense fibrous layer covered all over the surface of cartilage. In 8‐week group, the cartilaginous layer was similar to thickness of the normal cartilage, but still thinner than control. However, the fibrous layers covering condyle manifested slight degenerative changes, and even depressions and erosions were seen in the cartilage and subchondral bone. The trabeculae showed denser and multiply connected. In 8‐week group, the cartilaginous thickness of surgical condyles was significantly thinner than the contralateral. This study indicates that unilateral distraction of condylar neck loads the condyles asymmetrically. Asymmetrical loads affect more on the surgical condyles than the contralateral, and after 8 weeks of the post‐distraction, condyle could recover from asymmetrical loads in some degree.     

Choosing the best method to utilise single positron emission computed tomography (SPECT) scans in the management of unilateral condylar hyperplasia

Facial asymmetry secondary to unilateral condylar hyperplasia can be a diagnostic challenge to oral and maxillofacial surgeons. Single positron emission computed tomography (SPECT) scans provide a useful adjunct. We report a brief summary of the evidence describing the effectiveness of different methods of analysing SPECT scans and compare it with the results of a 10-year study at Sunderland Royal Hospital. Overall, both the evidence base and our study strongly favour use of the condyle:condyle ratio over the condyle:reference bone ratio, suggesting that no further comparisons are needed.     

Condylar hyperplasia. A clinico-pathological analysis of 22 cases

A series of 22 cases of unilateral condylar hyperplasia is presented with the emphasis on histopathological aspects. It is concluded that there are two types of condylar hyperplasia. The first manifests itself in the adolescent or the young adult and represents an exaggerated, normally proceeding growth and maturation process. The histological structure of the condyle in these cases is age-dependent as is shown by a conversion of hyaline growth cartilage into fibrocartilage occurring at about 20 years of age. The second type of condylar hyperplasia, seen in older people, probably represents reactive growth as a response to an eliciting agent that mostly can be identified. In these cases the histological architecture of the condyle is distorted by large masses of hyaline cartilage while there are concomitant degenerative changes in the form of arthrosis. In contrast to the patients suffering from the first type of condylar hyperplasia, the latter ones complain of additional joint symptoms, mostly pain. Moreover it is concluded that joint scintigraphy does not clearly discriminate between genuine condylar hyperplasia and reactive processes due to arthrosis, which may have clinical implications.     

Effects of a mandibular lateral shift on the condyle and mandibular bone in growing rats

OBJECTIVE: To examine the effects of mandibular lateral shift on the growth and morphology of the condyle and mandibular bone in growing rats. MATERIALS AND METHODS: A maxillary resin plate was designed to displace 4-week-old rat mandibles 2 mm to the left during closure. The plate was cemented, and the rats were killed after 2, 4, 8, or 12 weeks. Gross dimensions of the condylar head were measured. Radiographic films of the mandibles were exposed, and selected measurements were made. The newly formed bone in the condyle was evaluated with periodic acid and Schiff's reagent (PAS) staining. RESULTS: The length of the condylar head was greater on the ipsilateral side compared with the contralateral side. The experimental rats developed an asymmetric mandible, shorter in horizontal dimension but longer in the vertical dimension on the ipsilateral side. The mandibular growth direction was also affected, with the mandible on the ipsilateral side growing in a more anterior and superior direction. The amount of newly formed bone was greater in the superior subchondral region but lower in the posterior subchondral region on the ipsilateral side compared with the contralateral side. CONCLUSIONS: Mechanical stimuli delivered by a functional shift produce a series of morphological and histological responses in the condyle and lead to condylar and mandibular asymmetry in rats.     

Idiopathic noncondylar hemimandibular hyperplasia

A female patient with 'idiopathic non-condylar hemimandibular hyperplasia' was followed from the age of 7·5–11·5 years. This rare disorder was characterised by an increase in volume of the right inferior ramus and mandibular body. It also included accelerated development and eruption of the teeth on the affected side, but no indication of enlargement of the condyle or the condylar neck. To date, review of the literature revealed several cases of hemimandibular hyperplasia and unilateral condylar hyperplasia, both of which present with enlargement of the condyle. However, the patient differed significantly from any previously reported cases, since she had no enlargement of the condyle. The above mentioned patient also differed from patients with hemihypertrophy, since the teeth were accelerated in development, but not hyperplastic. In addition, from histopathologic and radiographic examinations, as well as an angiogram, benign fibro-osseous and vascular lesions of the mandible were excluded. Although this is a single case report and neither the aetiology nor the pathogenesis is yet understood, it may suggest a new disorder of the mandible. Therefore, future reporting of similar cases should be encouraged.     

The expressions of IGF‐1, BMP‐2 and TGF‐β1 in cartilage of condylar hyperplasia

Summary Condylar hyperplasia is a complex post‐natal growth abnormality of the mandible and condyle, which leads to facial asymmetry. We investigated the distributions of insulin‐like growth factors (IGF‐1), bone morphogenetic protein‐2 (BMP‐2) and transforming growth factor‐β1 (TGF‐β1) in cartilage of condylar hyperplasia and revealed relationships between age and the cartilaginous thickness. Twenty patients with condylar hyperplasia were divided into four histopathological types. The cartilaginous thickness and age in different histological types were analysed, and the localizations of IGF‐1, BMP‐2 and TGF‐β1 were detected by immunohistochemistry analysis. The cartilaginous thickness of condylar hyperplasia significantly increased. The cartilaginous thickness of type III was significantly thicker than type I and type II, Bivariate correlation revealed a significant correlations between age and the cartilaginous thickness (r = 0·68, P = 0·01). However, the expressions of IGF‐1, BMP‐2 and TGF‐β1 were the strongest in type I. In almost all types of condylar hyperplasia, the presence of IGF‐1 and BMP‐2 was found mainly in the proliferative chondrocyte layer and the hypertrophic chondrocyte layer, and only a few in the calcified chondrocyte layer. The presence of TGF‐β1 widely distributed from the fibrous articular surface to the calcified cartilage. These findings suggest that the proliferative activity of cartilage in condylar hyperplasia is strongly associated with age and cartilaginous thickness. Therefore, the four pathological types of condylar hyperplasia seem more likely to be four discontinuous stages.     

The influence of masseter activity on rat mandibular growth

Many studies have shown that mandibular and condylar growth is affected by compressive forces on mandibular bone and the condyle. It has been reported that chondroblastic differentiation and proliferation in chondrocytes play important roles in condylar growth. However, the influence of reduced compressive force on chondroblastic proliferation and mandibular bone formation is not fully understood. Thirty-six 3-week-old male Wistar rats were used in this study. In the experimental group, the masseter muscles were bilaterally resected to evaluate the influence of masticatory force on mandibular and condylar bone morphology. Six weeks after the operation, while the rats were in the pubertal growth stage, lateral X-rays were taken to analyze the skeletal pattern of the mandible. The form of the condyle and the thickness of the chondroblastic layers were evaluated by toluidine blue staining. Chondroblastic proliferation was identified by insulin-like growth factor-1 receptor (IGF-1r) immunostaining and bone resorption of the condyle was assessed by measuring tartrate-resistant acid phosphatase (TRAP) activity. Lateral X-rays of the mandible showed that rats in the experimental group tended to have large mandibular plane angles. The chondroblastic layer in the condyles of the experimental group rats was thinner than in the control group. The expression of IGF-1r immunopositive cells in the experimental group was significantly lower than in the control chondrocytes, and the number of TRAP-positive cells was significantly higher in the condylar bone of the experimental group. We conclude that masseter muscle activity is closely related to mandibular morphology during growth.     

Condylar displacement and mandibular bending deformation due to bite force]

The purpose of this study was to investigate the influence of the difference of the biting pivot positions, vertical dimensions and mandibular positions on the condylar displacement during clenching. The condylar displacement was measured by the Pantograph using the point of condyle on the Kinematic Axis as the representative and the Path of the Kinematic Axis (PKA) as the standard for the judgement of the displacement. The bending deformation of the mandible was also measured by a multi-vision and image analyzing system in order to correct its influence on the condylar displacement measured. The results were as follows: 1. The direction and magnitude of the condylar displacement changed with the biting pivot position. The bilateral condyles moved upwards deviating from the PKA when clenching on the bilateral 2nd-molar or the bi-or unilateral canine teeth; Whereas the biting-side condyle moved downwards and the idling condyle either moved upwards deviating from the PKA or backwards along the PKA when clenching on the unilateral 2nd-molar. 2. The displacement of the idling condyle was multi-directional when clenching on the habitual closure whereas it was unidirectional and of a smaller magnitude when clenching on the most retruded closure. 3. When clenching on the unilateral 2nd-molar, the mandible on the non-pivot side had an inward and upward bending deformation and the arch width decreased. It can be inferred that the actual idling condylar displacement was more inward and upward than that measured by the Pantograph.     

Frnkel矫治器对安氏Ⅱ类错患者髁突和下颌位置的影响

目的　了解Frankel矫治器治疗安氏Ⅱ类错过程中,髁突和下颌位置的变化情况。方法　选择经Frankel 矫治器治疗成功的安氏Ⅱ类错患者30例,男女各15例,对其治疗前后的头颅侧位定位片进行X线头影测量重叠分析。结果　①前颅底结构重叠显示治疗后患者的髁突点、下颌角点和颏前点发生明显的下移,同时男性患者颏前点发生明显的前移。②下颌结构重叠显示治疗后患者的髁突点发生明显的上移和后移(移位比约为2∶1),下颌角点相对颏部发生后移。结论　Frankel矫治器能刺激安氏Ⅱ类错患者髁突的生长,有利于下颌水平向的改建。     

Mirror image condylar hyperplasia in two siblings

A Hispanic family with an unusual clinical and radiological pattern of condylar hyperplasia is presented. Mirror images of condylar hyperplasia, malocclusion of teeth, and shift of midline of the mandible were seen in two brothers. The father had a similar abnormality of his left mandibular condyle. The condylar hyperplasia in this family indicates that mandibular condylar hyperplasias could be genetic in origin, possibly Y-linked or autosomal dominant.     

Osteochondroma of the mandibular condyle. Case report and its management.

1. A case of osteochondroma of the temporomandibular joint simulating a unilateral condylar hyperplasia is presented. 2. The need to divide the zygomatic arch to facilitate removal of large tumors is noted. 3. The removal of the growth resulted in normal functioning of the jaws with the disappearance of the features of unilateral hyperplasia. 4. Occlusal grinding is often necessary to correct the compensatory occlusal adjustment that occurs with the rotation of the mandible in these lesions. 5. The possibility of the presence of a tumor must be kept in mind when patients present with symptoms of unilateral condylar hyperplasia.     

Evaluation of treatment with unilateral mandibular sagittal split ramus osteotomy and maxillary osteotomy in patients with condylar osteochondroma and mandibular asymmetry: A retrospective case series

The aim of the study was to describe an approach where condylar resection with condylar neck preservation was combined with Le Fort I osteotomy and unilateral mandibular sagittal split ramus osteotomy (SSRO).Patients with a unilateral condylar osteochondroma combined with dentofacial deformity and facial asymmetry who underwent surgery between January 2020 and December 2020 were enrolled. The operation included condylar resection, Le Fort I osteotomy and contralateral mandibular sagittal split ramus osteotomy (SSRO). Simplant Pro 11.04 software was used to reconstruct and measure the preoperative and postoperative craniomaxillofacial CT images. The deviation and rotation of the mandible, change in the occlusal plane, position of the “new condyle” and facial symmetry were compared and evaluated during follow-up. Three patients were included in the present study. The patients were followed up for 9.6 months on average (range, 8–12). Immediate postoperative CT images showed that the mandible deviation and rotation and occlusion plane canting decreased significantly postoperatively; facial symmetry was improved but still compromised. During the follow-up, the mandible gradually rotated to the affected side, the position of the “new condyle” moved further inside toward the fossa, and both the mandible rotation and facial symmetry were more significantly improved.Within the limitations of the study it seems that for some patients a combination of condylectomy with condylar neck preservation and unilateral mandibular SSRO can be effective in achieving facial symmetry.     

Unilateral overgrowth and remodeling processes after fracture of the mandibular condyle

abstract – An overgrowth of the fractured side of the mandible coincided with the general skeletal growth spurt during puberty in two boys with unilateral fracture of the condylar neck and dislocation of the condyle. In one of the cases is demonstrated the formation of a condyle-like bony process and resorption of the dislocated condyle, which took place within a few months after fracture. The observation of mandibular overgrowth indicates that if no functional disorders necessitate interference, facial asymmetry after fracture of the condylar neck should not be corrected surgically in young persons until the prognosis of mandibular growth is estimated by means of cephalometric radiographic analysis.     

颅底结构螺旋CT影像的三维定量测量

目的　分析健康成人当下颌骨处在正常牙尖交错位时 ,髁突与颅底颈内动脉管外口、颈静脉窝、卵圆孔、棘孔、破裂孔等之间的空间位置关系 ,为术中对其他重要结构的位置评估提供依据。方法　选择健康成人 10 0名 ,在正常牙尖交错位时 ,用螺旋CT扫描、颅底三维影像重建 ,测量各结构间的最短距离和空间角度。 12个定点 ,测量 2 8项距离和空间角度以极坐标表示 ,髁突内缘点为中心点 ,髁突长轴为 0°轴作为参照系。结果　颌下入路能顺利显露髁突内缘点和髁突长轴的方向 ,以此为参照系 ,确定颈内动脉管外口外缘点为 12 0 1± 2 71mm ,5 14± 1 2 2° ,颈静脉窝外缘点为 15 11±2 72mm ,- 5 6 2 7± 14 0 5°。结论　以髁突内缘点为中心点 ,髁突长轴为 0°轴参照系有助于为颌下入路颅底手术的术中定位及颅底解剖教学提供参考。     

The clinical and radiographic characteristics of condylar osteochondroma

Osteochondroma is one of the most common benign bone tumors, but it is rare in the mandibular condyle. The purpose of this study was to increase the clinical and radiographic cognition of osteochondroma in the mandibular condyle. Thirty-four patients with radiographic and pathologic features of unilateral condylar osteochondroma were included in this retrospective study. All cases received clinical and radiographic examinations before tumor resection. Common manifestations included facial asymmetry, hypomobility, malocclusion, joint dysfunctions, and even external auditory canal stenosis. Osteochondroma might arise on the different condylar areas, such as the medial aspects (55.9%), anterior-superior (11.8%), posterior-superior (11.8%), lateral (8.8%), and generally enlarged (11.8%). The tumor formed a pseudojoint under the anterior eminence in 55.9%; the affected mandible presented normal shape in 58.8%; and horizontal mandibular deviation was caused by the tumor or elongated ramus in 70.6%. The condylar osteochondroma may locate in different positions encircling the condyle, which increases recognition and diagnosis of these lesions.     

Changes in parathyroid hormone-related protein and 3-dimensional trabecular bone structure of the mandibular condyle following mandibular distraction osteogenesis in growing rats.

PURPOSE: Distraction osteogenesis (DO) is commonly performed for mandibular reconstruction during the growth period. We tested the hypothesis that parathyroid hormone-related protein (PTHrP) in mandibular condylar cartilage and underlying trabecular bone in growing individuals undergo changes in response to distraction forces. MATERIALS AND METHODS: Forty-eight 6-week-old male Sprague-Dawley rats were used. Animals underwent unilateral mandibular distraction using a distractor that we devised, and unoperated animals were evaluated as controls. DO procedure was performed: 3 days' latency period, 0.4 mm/day rate, total 4.0 mm. Changes in cartilage morphology, PTHrP activity, and 3-dimensional trabecular bone structure changes measured by micro-computed tomography were examined at 0, 2, 4, and 6 weeks of consolidation. RESULTS: A marked irregularity was noted in the superior portion of the distracted side's condylar cartilage that resolved after distraction ceased. PTHrP was more strongly expressed in the hypertrophic layer of condylar cartilage on the distracted side than in controls, up to 6 weeks after the end of distraction. Subchondral trabecular bone volume, percent bone volume, and trabecular number in the superior and posterior regions of the condyle decreased significantly by 2 weeks after distraction. These parameters returned to normal in the posterior condyle, but not in the superior part of the condyle by 6 weeks following distraction. CONCLUSION: These results suggest that unilateral mandibular distraction in growing rats causes temporary morphologic alterations of trabecular bone structure on the distracted side accompanied by increased production of PTHrP in the mandibular condyle.