下颌骨牵引成骨的研究进展和临床应用

牵引成骨是矫治骨骼畸形的一种新型技术.在颅颌面畸形整复外科领域中,以下颌骨牵引成骨方面的研究报道最多,本文就下颌骨牵引成骨的牵引原则、牵引装置、牵引生物力学及临床应用等内容作一简要综述.     

下颌骨牵引成骨术对下牙槽神经的影响

牵引成骨术[1] 在颌面外科主要用于矫治小下颌畸形、半侧颜面发育不全畸形 ,并在上下颌骨宽度不足、严重上颌后缩畸形、下颌骨或牙槽骨缺损治疗方面显示出独特优势。下牙槽神经 (ｉｎｆｅｒｉｏｒａｌｖｅｏｌａｒｎｅｒｖｅ ,ＩＡＮ)位于骨性下颌管中 ,在下颌骨牵引过程中会同时受到牵拉 ,这是否会损伤ＩＡＮ的形态结构 ,能否完全恢复 ,目前意见不统一。我们通过动物实验研究 ,探讨下颌骨牵引成骨术对ＩＡＮ形态结构的动态影响。一、材料和方法青年恒河猴 16只 ,年龄 3～ 4岁 ,体重 5～ 7ｋｇ。 10只行单侧下颌骨牵引延长 ,6只行双侧下颌骨…     

吻合血管腓骨皮瓣一期修复下颌骨巨大缺损

巨大的下颌骨肿瘤常可侵犯口腔粘膜和皮肤，彻底切除后造成下颌骨和粘膜的巨大缺损。应用吻合血管的排骨骨皮瓣一期修复骨和软组织缺损２例，获得满意效果。排骨骨皮瓣切除范围大，血供较恒定，易于切取，为巨大下颌骨肿瘤侵犯粘膜或皮肤病例的长度切除和一期修复开创了一种新的术式。     

复合富血小板血浆珊瑚骨修复下颌骨缺损

BACKGROUND: Platelet rich plasma contains various growth factors, such as platelet-derived growth factor, metastatic growth factor, insulin-like growth factor, epidermal growth factor as well as vascular endothelial growth factor. Therefore, it can directly or indirectly promote cell differentiation and proliferation in different stages of bone regeneration.     

新西兰兔下颌骨牵引成骨早期拆除牵引装置植入钛钉对新骨形成的影响

目的：利用锥形束CT（ CBCT）研究新西兰兔下颌骨矩形截骨后,早期拆除牵引装置植入钛钉对新骨形成 的影响,探讨牵引成骨早期拆除牵引装置的可能性。方法：新西兰兔下颌骨矩形截骨12 mm×4 mm,植入自制牵 引装置。牵引5 d 后,随机分为稳定4 周、稳定8 周、钛钉植入3 组。前2 组分别于稳定期4 周、8 周时处死动物;钛 钉植入组,稳定期4 周时,取出牵引器植入钛钉,4 周后处死动物;拍摄CBCT和X线片。结果：兔下颌骨垂直高 度平均增加（2.25±0.41）mm。稳定4 周、8 周和钛钉植入组的术区CT值分别为（80.00±12.36）Hu、（293.00±37.66） Hu和（289.25±38.87）Hu。稳定4 周术区CT值低于稳定8 周和钛钉植入组,后2 组CT值相近。结论：早期拆除 牵引装置植入钛钉与常规固定相比,骨形成没有明显影响,临床应用可有效地缩短牵引成骨的时间。     

富血小板纤维蛋白促进兔下颌骨牵引成骨

目的:通过建立兔下颌骨牵引成骨模型,探讨富血小板纤维蛋白(PRF)在牵引成骨中的作用,为临床研究与应用提供参考依据。方法:在成年白兔的一侧下颌骨前部行骨切开术,用牵引器延长一侧下颌骨4 mm,牵引间隙放置PRF膜为实验组;另一侧下颌骨行骨切开并安置牵引器,作为对照组,分别于稳定期的第3、7、14、28天处死动物,取牵引区新生骨痂,行大体标本观察、X线影像观察、H-E切片观察,比较2组的成骨效果,并进行骨计量学分析,计算新生骨小梁面积百分比。结果:新生骨小梁面积在不同时间点的实验组均显著大于对照组。组织学观察表明,不同时间点实验组骨成熟程度均高于对照组。结论:PRF在兔下颌骨牵引成骨中具有较显著的促进成骨的作用。     

山羊牵张成骨术后下颌骨三维有限元模型建立

牵张成骨是矫治颅颌面先天发育畸形和获得性骨节段缺损的新兴技术.本研究在实施山羊下颌骨牵张成骨术的动物实验基础上,通过CT断层扫描技术结合专业图像处理软件Mimics和自编Matlab程序建立可用于应力分析的山羊下颌骨三维有限元模型.     

磷酸钙骨水泥与骨形态蛋白复合材料修复下颌骨缺损的研究

为提高磷酸钙骨水泥的成骨活性，将自制的磷酸钙骨水泥作为骨形态蛋白．2的载体予以复合，对复合载体材料进行物性研究和异位成骨试验。并以该复合材料修复兔下颌骨缺损，通过生物力学检测和骨界面新生骨计量，观察其修复下颌骨缺损的效果。结果表明，以该复合材料修复兔下颌骨缺损，其材料与宿主骨界面的结合强度以及新生骨量均明显高于单纯材料的修复。     

The Influence of Expansion Rates on Mandibular Distraction Osteogenesis: A Computational Analysis

Mandibular distraction osteogenesis is a clinical procedure used for modifying the mandibular geometry when problems of dental overcrowding and arch shrinkage occur. The objective of this study is to use a computational model of tissue differentiation to examine the influence of the rate of distraction on bone re-growth within the fracture callus of a human mandible submitted to symphyseal distraction osteogenesis. A 3D model of the mandible is reconstructed from CT scan data and meshed into finite elements. Two different mastication loadings have been investigated: a ‘full’ mastication load and a ‘reduced’ mastication load where the action of each muscle was reduced by 70%. Four different distraction rates were analyzed: 0.6, 1.2, 2, and 3 mm/day, allowing a total displacement of 6 mm. In the early stages of the distraction process it is predicted that there is a decrease in the amount of bone tissue forming within the center of the fracture gap for all distraction rates. After the initial phases of expansion, the bone tissue within the callus increases for the slower rate of distraction or continues to decrease at the faster rates of distraction. At the end of the simulated maturation period, 47% of the distracted callus was predicted to consist of bone tissue for a distraction rate of 0.6 mm/day, decreasing to 22% for a distraction rate of 3 mm/day. Significantly higher amounts of bone formation were predicted for all distraction rates for the case of reduced mastication loading. Disparities between the model predictions and what is observed in vivo were found. For instance, during the latency period, the distraction period and beyond, the model is predicting larger than expected amounts of cartilage tissue formation within the callus. This and other limitations of the proposed model are discussed and possible specific explanations for these disparities are provided in the paper. The model predicts a distraction rate of around 1.2 mm/day to be optimal as higher rates produce less bone tissue while the risk of a premature bone union is greater at slower rates of distraction because in the latter stages of the distraction process bone tissue is predicted to form between the left and right side of the bone callus.     

Targeting P38 Pathway Regulates Bony Formation via MSC Recruitment during Mandibular Distraction Osteogenesis in Rats

Distraction osteogenesis (DO) is a widely used self-tissue engineering. However, complications and discomfort due to the long treatment period are still the bottleneck of DO. Novel strategies to accelerate bone formation in DO are still needed. P38 is capable of regulating the osteogenic differentiation of both mesenchymal stem cells (MSCs) and osteoblasts, which are crucial to bone regeneration. However, it is not clear whether targeting p38 could regulate bony formation in DO. The purpose of the current work was to investigate the effects of local application of either p38 agonist anisomycin or p38 inhibitor SB203580 in a rat model of DO. 30 adult rats were randomly divided into 3 groups: (A) rats injected with DMSO served as the control group; (B) rats injected with p38 agonist anisomycin; (C) rats injected with p38 inhibitor SB203580. All the rats were subjected to mandibular distraction and the injection was performed daily during this period. The distracted mandibles were harvested on days 15 and 30 after surgery and subjected to the following analysis. Micro-computed tomography and histological evaluation results showed that local application of p38 agonist anisomycin increased new bone formation in DO, whereas p38 inhibitor SB203580 decreased it. Immunohistochemical analysis suggested that anisomycin promoted MSC recruitment in the distraction gap. In conclusion, this study demonstrated that local application of p38 agonist anisomycin can increase new bone formation during DO. This study may lead to a novel cell-based strategy for the improvement of bone regeneration.     

犬下颌骨节段性缺失的有限元模型的建立

目的：建立犬下颌骨节段缺失的有限元模型。方法：运用Mimics软件读取基于实验犬下颌骨CT资料的DICOM数据形成几何模型,在Magics软件中使用cut工具对几何模型进行切割,模型由缺损侧和非缺损侧下颌骨、重建钛板组成,每个部分依靠Magics的粘接功能粘在一起,生成实体单元后在MARC软件中完成模型的力学分析。结果：建立了犬下颌骨节段缺失的有限元模型,可模拟牵张过程,观察任意点的应力、位移情况,并可选取模型的任意部分,查看其相应计算结果。结论：犬下颌骨节段缺失的有限元模型的建立为进一步研究节段缺损下颌骨的各种生物力学状况奠定了基础。     

牵张延长下颌骨对二腹肌纤维型构成影响的研究

目的 :研究牵张延长下颌骨前后二腹肌的组织化学特征。方法 :应用肌球蛋白ATP酶 (pH9.4)染色法 ,观测了牵张前后 8只狗的二腹肌肌纤维类型 ,并用VIDAS图像分析仪测量其横截面积。结果 :ATP酶染色 ,二腹肌肌纤维分为Ⅰ型和Ⅱ型 ,Ⅰ型纤维数量较Ⅱ型纤维少。牵张延长下颌骨后 ,Ⅰ型纤维数量显著性增多 ,Ⅱ型纤维数量显著性减少。牵张成骨后 ,Ⅰ型纤维、、Ⅱ型纤维的横截面积与术前比较没有显著性差异。结论 :牵张延长下颌骨后 ,与牵张方向平行的二腹肌肌纤维型分布发生了与功能变化相适应的改变     

Distraction osteogenesis for correction of post ankylosis mandibular deformities

Temporomandibular joint ankylosis, a debilitating disease mainly affecting children, is characterized by progressive restriction of mouth opening and maxilla-mandibular developmental deformities. Craniofacial distraction osteogenesis has been developed as a standard surgical strategy for rectification of craniofacial deformities. The purpose of this study was to assess mono-planar distraction devices for the correction of various mandibular asymmetries in patients with unilateral temporomandibular joint ankylosis who developed restricted mouth opening and mandibular retrognathia. All patients were treated using one-stage distraction osteogenesis followed by temporalis fascia interpositional arthroplasty under general anesthesia. A significant increase in mandibular ramus and base length was observed. Although an increase in anterior lower facial height was observed, it was not significant statistically. A decrease in posterior lower facial height and corpus was observed. Oblique distraction with angular osteotomy allowed lengthening of both the ramus and corpus, yielding satisfactory results and hence eliminating the need of secondary surgery. In conclusion, univector internal distractors are effective for correction of multi-planar mandibular deficiencies by optimizing its placement through meticulous planning.     

富血小板纤维蛋白对兔下颌骨牵引成骨区骨形态发生蛋白-4表达的影响

目的:探讨富血小板纤维蛋白(PRF)对牵引成骨区骨形态发生蛋白-4(BMP-4)表达的影响。方法:25只大耳白兔随机分2组,分别行双侧下颌骨皮质骨切开术,一侧下颌骨牵引间隙放置PRF膜作为实验组,对侧作为对照组,分别于稳定期第3、7、14、21、28天处死一组动物,切取牵引间隙处骨痂行H-E染色和BMP-4免疫组织化学显色,细胞图像分析仪测量牵引间隙处骨痂BMP-4表达情况。结果:下颌牵引延长后牵引间隙均有新骨形成,免疫组织化学显色显示BMP-4主要定位于成骨细胞的细胞质中。实验组在稳定期3、7、14、21 d BMP-4表达的阳性细胞率和阳性面积百分比均显著高于对照组,稳定期28 d BMP-4表达的阳性细胞率和阳性面积百分比与对照组比较差异均无统计学意义。结论:PRF能促进兔下颌骨牵引成骨区新骨的生成,BMP-4可能在牵引成骨过程中调控组织细胞应力信号传递,发挥成骨作用。     

聚醚醚酮(PEEK)个性化重建板修复下颌骨缺损的三维有限元分析

目的应用三维有限元分析聚醚醚酮(PEEK)及其复合物重建板修复下颌骨缺损的应力分布。方法通过CBCT、Mimics、SolidWorks、Geomagic Studio和ANSYS Workbench等软件建立钛合金、聚醚醚酮(PEEK)、30%碳纤维增强聚醚醚酮(carbon-fiber-reinforced polyetheretherketone,CFR-PEEK)、68%CFR-PEEK重建板有限元模型,以钛合金作为对照。分别模拟两种咬合状态。载荷Ⅰ:前牙区垂直加载300 N;载荷Ⅱ:左侧后牙区垂直加载300 N。结果两种载荷下,重建板最大应力与其屈服强度的比值:PEEK模型30%CFR-PEEK模型钛合金模型68%CFR-PEEK模型;颌骨最大应力:PEEK模型30%CFR-PEEK模型钛合金模型68%CFR-PEEK模型。其中,在前牙区垂直载荷下,PEEK模型重建板和颌骨的最大应力都超过了其屈服强度,其他模型的最大应力均低于其屈服强度。结论 68%CFR-PEEK与钛合金有着相似的应力分布,可以满足颌骨缺损重建机械强度的要求,重建板出现断裂的风险较钛合金降低,但应力屏蔽的发生率略增高。研究结果可为修复下颌骨缺损的重建板材料的选择和临床应用提供依据。     

Tissue differentiation and bone regeneration in an osteotomized mandible: a computational analysis of the latency period

Mandibular symphyseal distraction osteogenesis is a common clinical procedure to modify the geometrical shape of the mandible for correcting problems of dental overcrowding and arch shrinkage. In spite of consolidated clinical use, questions remain concerning the optimal latency period and the influence of mastication loading on osteogenesis within the callus prior to the first distraction of the mandible. This work utilized a mechano-regulation model to assess bone regeneration within the callus of an osteotomized mandible. A 3D model of the mandible was reconstructed from CT scan data and meshed using poroelastic finite elements (FE). The stimulus regulating tissue differentiation within the callus was hypothesized to be a function of the strain and fluid flow computed by the FE model. This model was then used to analyse tissue differentiation during a 15-day latency period, defined as the time between the day of the osteotomy and the day when the first distraction is given to the device. The following predictions are made: (1) the mastication forces generated during the latency period support osteogenesis in certain regions of the callus, and that during the latency period the percentage of progenitor cells differentiating into osteoblasts increases; (2) reducing the mastication load by 70% during the latency period increases the number of progenitor cells differentiating into osteoblasts; (3) the stiffness of new tissue increases at a slower rate on the side of bone callus next to the occlusion of the mandibular ramus which could cause asymmetries in the bone tissue formation with respect to the middle sagittal plane. Although the model predicts that the mastication loading generates such asymmetries, their effects on the spatial distribution of callus mechanical properties are insignificant for typical latency periods used clinically. It is also predicted that a latency period of longer than a week will increase the risk of premature bone union across the callus.     

下颌管位置与下颌支矢状劈开术的关系

在50侧成人下颌骨的切面上,观察测量了下颌管在下颌支矢状截骨术的位置,下颌管至下颌骨内、外侧面,上、下缘的距离等。从解剖学角度讨论了术中防止下齿槽神经损伤的要点。     

一种体外贴壁细胞应变加载装置的研制

目的开发一套新型的应变加载装置,用于贴壁细胞力学生物学研究。方法该装置基于基底形变加载技术,采用可控制编程器驱动步进器,引起硅橡胶小室变形,实现多单元大应变的细胞加载;研制该装置,检测机械性能;建立硅橡胶小室的三维模型,利用有限元技术对硅橡胶小室进行仿真,分析该小室的应变场均匀性问题;采用该装置对骨髓间充质干细胞(bone marrow stromal cells,BMSCs)加载5%机械应变,频率0.5 Hz,2 h/d,持续5 d,并在倒置显微镜下观察细胞形态的变化。结果所研制的适用于体外细胞加载装置可对3组细胞加载基底实现最大至50%机械单向应变;在10%应变范围内,硅橡胶小室底部的均匀应变场面积占比保持在50%以上,保证了细胞受力均匀; BMSCs形态发生明显变化,排列方向趋于垂直主应变加载方向。结论该装置运行可靠,应变范围宽,频率可调,操作方便,可同时对多组细胞培养基底进行应变加载,为细胞力学生物学研究提供了便利条件。