运用输送盘牵张成骨术重建猴下颌髁突的实验研究

目的研究在猴颞下颌关节（TMJ）缺损动物模型上运用输送盘牵张成骨术重建髁突的可行性及其整复效果。方法选取6只成年恒河猴,手术截除其双侧关节髁突与关节盘,在下颌升支部行“L”形骨切开术,形成骨输送盘,并安置自行研制的牵张器。按每次0.4 mm,每次间隔12 h的牵张速率向上牵引输送盘至关节窝。牵张结束后第4、12、24周各处死2只动物。通过影像学分析和组织学检查评价输送盘改建与牵张间隙内新骨生成情况。以术中切除的髁突作为正常对照组。结果术后所有动物都有不同程度的咬合错乱,牵张结束后咬合基本恢复正常。骨输送盘形态基本接近正常髁突,其下方可见大量软骨细胞;牵张间隙内新骨生成良好。结论输送盘牵张成骨术可以重建一个形态和功能都基本接近正常的髁突,这种技术可以作为一种整复TMJ缺损的新方法。     

输送盘牵张成骨术重建下颌髁突后对下颌骨生长发育的影响

目的:研究输送盘牵张成骨术重建下颌髁突后对下颌骨生长发育的影响.方法:选用3～4 月龄健康幼年雄性山羊16 只,手术切除右侧髁突(保留关节盘),在右下颌升支行反"L"形骨切开术形成骨输送盘,并安置牵张器.以每日2 次,每次0.4 mm的速率向上牵引输送盘至关节窝.在手术后当天、牵张结束后当天、牵张结束后4、12、24、48 周时行三维CT检查评价输送盘改建及牵张间隙内新骨形成情况,并分别于12、24、48 周3 个时间点各处死动物2 只对新生髁突做组织学检查.牵张结束后48 周时处死剩余10 只动物,对下颌骨及重建髁突形态进行观察与测量.左侧下颌骨作为正常对照组.结果:三维CT显示新生髁突形态逐渐改建并接近正常髁突,牵张间隙新骨生成良好.大体观察发现新生髁突体积较正常侧明显增大,但下颌骨的生长与正常侧无显著差异.新生髁突表面有一层纤维软骨覆盖,组织学结构与正常关节软骨类似.结论:输送盘牵张成骨重建髁突未对下颌骨的生长发育产生明显影响;下颌运动产生的功能刺激是下颌骨继续生长发育的主要原因.     

髁突手术对其压缩力学性能及骨密度的影响

目的 探讨不同术式后髁突力学性能的变化及与材料特性之间的关系。方法 采用压缩力学性能测试技术和双能Ｘ线吸收法，定量分析１２例正常、６例髁突高位切削术及６侧关节重建术的成年杂种犬髁突的压缩力学性能和骨矿含量。结果 髁突的载荷与位称呈非线性关系。其弹性极限负荷及位移、最大负荷及位移以正常组为最高，而刚度及骨矿含量则以切削组为最高，减径组各项指标均最低。３组髁突弹性极限负荷、最大负荷及刚度与骨密度之间均     

有限元法分析犬下颌不全截骨牵张时特定标志点应力状况

目的:利用犬不完全截骨牵张成骨有限元模型计算牵张过程中下颌骨特定点受力状况。方法:有限元模型模拟不完全截骨(截骨处剩1mm舌侧皮质骨),观察下颌骨特定标志点所受最大主应力和Von Mises应力。结果:犬下颌不全截骨牵张时,在牵张侧下颌角、喙突受到较大应力,第五臼齿、髁状突前斜面前缘中点和髁状突后斜面后缘中点VonMises应力分别为:0.3726 MPa、0.2408 MPa、0.1051 MPa,并且前两点所受最大主应力为压应力、后缘中点为拉应力,在非牵张侧应力为0。结论:犬下颌骨不全截骨牵张成骨时,牵张侧受到不同程度应力影响,在非牵张侧不受应力影响。     

犬下颌骨单侧不全截骨牵张时牵张侧位移状况有限元分析

目的 运用犬下颌单侧不全截骨牵张成骨有限元模型,计算下颌骨在牵张过程中牵张侧各部分位移状况。方法 有限元模型模拟犬下颌单侧不全截骨牵张,观察当滑动骨块未被牵开和被牵开时牵张侧关节、下颌角、喙突及牙齿等6个标志点的位移状况。结果 下颌滑动骨块未被牵开时牵张侧第五臼齿、髁状突前斜面前缘中点所受最大主应力为压应力,髁状突后斜面后缘中点为拉应力,各标志点在空间X、Y、Z三轴位移不明显;当下颌骨滑动骨块被牵开1 mm时,上述各点位移明显增加。结论 从牵张侧观察,牵张侧下颌骨在矢状平面上和冠状平面上都有以髁突顶点(横嵴中点)为中心的逆时针旋转趋势。     

钛-镍记忆合金牵张成骨的新生骨骨密度及生物力学测试

目的通过对牵张成骨新生骨的骨密度和生物力学测试，研究钛-镍记忆合金牵张器牵张成骨的质量。方法选用成年杂种犬12只，下颌两侧拔牙后用全埋置钛-镍记忆合金牵张器完成牵张手术，左侧为实验侧，右侧为自身对照。分别在牵张完成后3、6个月进行双能x线骨密度测量和压缩生物力学测试。结果术后3个月，牵张区新生骨骨密度、抗压强度、弹性模量低于对照侧；6个月，各项指标均有增加，与对照侧的差异无统计学意义。结论用钛-镍记忆合金牵张器牵张，增高犬下颌后牙区牙槽嵴，新生骨质量可以满足种植等后期修复的要求。     

用三焦点牵张成骨技术修复重建颏部骨缺损的实验研究

目的:探讨应用三焦点牵张成骨技术修复重建颏部骨缺损的可行性及其方法。方法:选取4只成年恒河猴,通过下颌前份骨截除术形成颏部正中联合骨缺损。在两侧下颌体部各制备一个输送盘,并用自行研制的可调式多平面牵张装置使双侧输送盘向前内方向缓慢移动,并在颏部正中对接以修复重建颏部骨缺损。通过X线片与螺旋CT三维重建技术检查双侧输送盘移动与新骨形成情况。在牵张结束的第8和16周分别处死2只动物,取下颌骨牵张区标本作组织学检查。结果:牵张结束后,4只恒河猴的颏部形态接近正常猴,X线片与螺旋三维CT片显示两侧输送盘远心端在正中成功对接。牵张结束的第8周,螺旋三维CT与实验组织学观察发现牵张间隙内均有新骨形成;两侧输送盘在下颌正中呈纤维连接,并可见活跃的成骨和改建活动。牵张结束的第16周,牵张间隙内新骨成熟,两侧输送盘下颌正中逐渐呈纤维骨性连接。结论:用可调式多平面牵张装置进行三焦点牵张成骨可以作为修复重建颏部骨缺损的一种选择手段。     

输送盘牵张成骨重建颅颌面骨缺损的研究进展

输送盘牵张成骨已成为重建人类长骨大范围组织缺损极为有效的方法之一.用其也可高效地重建颅颌面骨因创伤、肿瘤术后、骨髓炎以及骨愈合不良等造成的大范围骨组织缺损.本文就输送盘牵张成骨在颅颌面骨缺损重建的应用作一综述.     

牵张器结合脱细胞真皮基质增高牙槽嵴新生骨骨密度及生物力学测试实验

目的 观察牵张后犬下颌牙槽嵴高度、骨密度及生物力学的动态变化,探讨镍钛记忆合金牵张器结合异种脱细胞真皮基质增高牙槽嵴后对成骨质量的影响.方法 健康成年雄性杂种犬12只分为两组,1个月组和3个月组各6只,每只动物下颌骨又分为实验侧和对照侧.建立牙槽嵴萎缩模型后,在一侧下颌行牵张手术,放入脱细胞真皮基质及两个直径1.0 mm,复形温度为33℃的"S"形牵张器,该侧为实验侧;另一侧为对照侧,不放脱细胞真皮基质,仅放入同样牵张器行牵张术.术后1、3个月各处死6只实验动物,切取下颌骨标本,用双能X线骨密度仪扫描3个部位,即:牵张间隙上方、下方及牵张间隙,观察其骨密度,使用生物材料实验机测试牵张区骨块抗压强度和弹性模量.结果 牵张术后3个月,实验侧骨密度:牵张间隙上方(0.714±0.238)g/cm2、牵张间隙(0.512±0.435)g/cm2、牵张间隙下方(0.615±0.043)g/cm2.最大抗压强度(36.54±7.32)Mpa,弹性模量(1674.10±256.43)Mpa,均高于对照侧.结论 脱细胞真皮基质作为屏障膜,能提高牵张区成骨质量,增加骨强度,在镍钛记忆合金牵张成骨过程中是一种理想的引导骨再生生物膜.     

内置自加载牵张器重建兔下颌支的实验研究

目的 :探索牵张成骨重建下颌支缺损的新方法。方法 :以成年新西兰兔为实验动物 ,手术切除下颌骨一侧部分升支及髁状突 ,造成 1.5cm的节段性骨缺损 ,骨断端”L”形截骨形成传送盘 ,安置可完全埋置于组织内的镍钛记忆合金牵张器 ,术后 2个月时处死实验动物 ,取下颌骨观察骨缺损修复情况。结果 :镍钛记忆合金牵张器能自动完成牵张成骨 ,初步重建了缺损的下颌支 ,组织学检查可见牵张区有良好的新骨再生。结论 :内置镍钛记忆合金牵张器可自动持续弹性加载牵张成骨 ,可望成为一种具有良好应用前景的简便实用技术。     

Biomechanical properties of the condyle created by osteodistraction

A new condyle can be reconstructed by osteodistraction, but the biomechanical properties of the neocondyle remain unknown. This study examined the hypothesis that the biomechanical properties of neocondylar cancellous bone could reach control levels 24 weeks after its creation by osteodistraction. The right mandibular condyles were removed and reconstructed by osteo-distraction in 16 adult goats. Their contralateral condyles served as controls. Microstructural and mechanical properties were examined by microcomputed tomography and mechanical testing. At 24 weeks after distraction, the neocondyle grew larger in size, but the shape and histological features were similar to those of the controls. The cancellous bone of the neocondyle even appeared to be more dense and stiffer in comparison with the control condyle. The results of this study suggest that the neocondyle created by osteodistraction develops nearly normal biomechanical properties for functional loading by 24 weeks after creation.     

Reconstruction of mandibular condyle by transport distraction osteogenesis: Experimental study in rhesus monkey.

PURPOSE: This study investigated histomorphologic changes in the newly formed condyle reconstructed by transport distraction osteogenesis through a nonhuman primate model. MATERIALS AND METHODS: Six adult rhesus monkeys were used in this study. Bilateral condyles and articular discs were extirpated, and the technique of transport distraction osteogenesis was carried out to reconstruct the condyles. X-ray and 3-dimensional (3D) computed tomography (CT) scanning films were taken at various intervals. Two monkeys were killed respectively at 4, 12, and 24 weeks after completion of distraction; the transport segments and the distracted calluses were harvested and processed for histologic examination. The original condyles removed at surgery served as normal control. RESULTS: Open bite was seen in all animals postoperatively and diminished at the end of distraction. Bone regeneration was perfect in the distraction gap between the transport disc and the pre-existing mandible. The bony transport disc gradually remodeled to a neocondyle that was similar to the original condyle in the appearances and structures. The head of neocondyle was covered with a fibrous cap, which might play the role of an articular disc. CONCLUSION: A neocondyle with functional shape can be created by transport distraction osteogenesis. This suggests that this technique is an alternative method for reconstruction of the mandibular condyle.     

Transport distraction osteogenesis as a method of reconstruction of the temporomandibular joint following gap arthroplasty for post-traumatic ankylosis in children: a clinical and radiological prospective assessment of outcome

This clinical and radiographic study investigated the use of transport distraction osteogenesis in unilateral temporomandibular joint (TMJ) ankylosis patients. Six patients aged between 4 and 8 years were selected for the study; the mean preoperative maximal inter-incisal opening (MIO) was 3.5 mm without lateral and protrusive mandibular movements. The ankylotic mass along with the posterior border of the ascending ramus was exposed via ‘lazy-S’ incision. A gap arthroplasty was performed, followed by a ‘reverse L’ osteotomy on the posterior border of the ramus. In-house manufactured extraoral distraction devices were used for this prospective study. Follow-up clinical and radiographic evaluation was carried out for 13–27 months after completion of the activation period. After a mean follow-up of 19 months, the mean MIO was 29.1 mm and the lateral and protrusive movements changed from none to slight. Cone beam computed tomography images of all patients showed remodelled neocondyle created by transport distraction osteogenesis with no statistically significant differences observed for average cancellous bone density, trabecular number, and trabecular spacing between the neocondyle of the operated side (test) and the condyle of the non-operated side (control). Neocondyle formation by transport distraction osteogenesis using the in-house distraction device is a promising treatment option for TMJ reconstruction in ankylosis patients.     

牵引成骨结合组织工程化软骨重建山羊髁突缺损的实验研究

目的：利用牵引成骨结合组织工程化软骨重建山羊髁突缺损。方法：12只山羊随机分为两组：实验组在下颌切迹下方作截骨线,切除一侧髁突及其颈部,左右随机。再于下颌支后缘形成转移盘,在转移盘的远中植入软骨细胞支架复合物。对照组在转移盘的远中仅植入支架。分别于牵引结束4、8、12周大体及组织学观察山羊髁突的形成情况。结果：牵引结束后4周,实验组山羊髁突已具备良好的外形,髁突表面覆盖软骨组织：对照组山羊新形成之髁突外形虽与正常髁突相似但表面无软骨层。12周时,实验组山羊髁突外形与正常髁突相似,表面仍有软骨层覆盖：而对照组山羊新形成的髁突外形虽与正常髁突相似,但表面仍无软骨层覆盖。结论：利用牵引成骨结合组织工程化软骨的方法不仅可以从外形上重建山羊髁突,而且在解剖结构上与正常髁突相似,为髁突正常功能的行使提供了良好的解剖学基础。     

Reconstruction of a neocondyle using transport distraction osteogenesis

The process of slow bone expansion by distraction osteogenesis in conjunction with functional remodeling can also be used for the reconstruction of a neomandible and neocondyle. This is the technique of transport distraction osteogenesis. A transport disc is surgically created adjacent to the area of a discontinuity defect, and the transport disc is advanced by the process of distraction osteogenesis, using the Ilizarov principles. The mandible therefore acts as the bony template for reconstruction such that the neomandible created from the distraction process has the same size and shape as the native mandible covered by gingiva. This allows for enhanced prosthetic reconstruction. A reverse-L osteotomy of the ramus can also be performed to create a transport disc to reconstruct a neocondyle. Because the leading edge of the transport disc becomes enveloped by a fibrocartilagenous cap, the ramal transport disc can be moved superiorly to create a new articulation. Patients are encouraged to open and close their mouths during the distraction process, such that the transport disc remodels to form a neocondyle. This technique was successfully used to treat patients with degenerative joint disease, condylar resorption, and bony ankylosis.     

双侧下颌牵张成骨对转化生长因子β1在颞下颌关节髁突表达的影响

目的　研究狗的双侧下颌牵张成骨中颞下颌关节髁突的形态改变及转化生长因子β1(TGF-β1)在髁突的 表达。方法　16只狗随机分为4组,每组4只,分别为牵张6 d组、牵张后固定2周组、牵张后固定8周组及正常对 照组。各实验组的牵张频率均为1 mm/d,1次/天。对每组动物的髁突标本进行苏木精-伊红染色及TGF-β1的免 疫组化染色观察。结果　苏木精-伊红染色可见实验组动物的髁突纤维软骨早期有不同程度的损伤,增殖带、肥 大带细胞增生活跃,软骨钙化层及其深层软骨成骨活跃;TGF-β1阳性染色主要定位在肥大带细胞胞浆、周围基质和 成骨反应活跃处的成软骨细胞、成骨细胞及周围基质。牵张后固定2周时这种改建修复现象最明显,8周时逐渐恢 复至正常对照组的表现。结论　双侧下颌牵张成骨对颞下颌关节髁突影响主要表现为髁突纤维软骨组织形态学 的改变和软骨、骨的改建活动,但随着固定时间的延长这种改变逐渐修复。     

Long-term evaluation of the stability of reconstructed condyles by transport distraction osteogenesis

This retrospective longitudinal study evaluated the long-term stability of reconstructed condyles by transport distraction osteogenesis of the mandibular ramus in patients with unilateral temporomandibular joint (TMJ) ankylosis. 7 patients were followed up for 16–92 months (mean 39.4 months). The mean age of the patients at the time of distraction was 22.9 years (range 7–44 years). Maximal mouth opening and panoramic radiographs were recorded preoperatively, at the time of device removal and several years after removal of distraction device. At follow-up, cone beam CT images of the TMJ were obtained to confirm the changes of the reconstructed condyle. Absolute height (Co–Inc) and relative height (Co–Inc/Co–Go) of the reconstructed condyle and the asymmetric difference ratio (AR) were examined to assess the changes of condylar height and mandibular symmetry. The mean maximal mouth opening was stable during the period of follow-up. The mean absolute height and relative height of the reconstructed condyle decreased significantly (P < 0.05). Although no significant difference was found, the mandibular asymmetry difference ratio increased by 16.7%. These results suggested that the heights of reconstructed condyles were not stable in the long-term, and the mandible tended to be asymmetrical.     

Temporomandibular joint bony ankylosis: comparison of treatment with transport distraction osteogenesis or the matthews device arthroplasty

Temporomandibular joint (TMJ) bony ankylosis with micrognathia is a rare congenital condition that is difficult to treat and may result in recurrence. In a series of affected patients, we compared two new methods of treatment: transport distraction osteogenesis and Matthews Device arthroplasty. All patients had computed tomography scan documented bilateral TMJ bony ankylosis. Group I (transport distraction osteogenesis) underwent distraction advancement of the mandible (for micrognathia) followed by resection of the condyles, recontouring of the glenoid fossas with interposition temporoparietal-fascial flaps, and transport distraction osteogenesis of mandibular rami segments. Group II (Matthews Device arthroplasty) underwent all of the above procedures except for transport distraction osteogenesis. Instead, the Matthews Devices were anchored to the temporal bone and mandibular rami. Hinged arms allowed for motion at the reconstructed TMJ. In both groups, patients underwent extensive postoperative therapy. Preoperative, postoperative, and follow-up lateral cephalograms were obtained, and incisor opening distances were recorded. All patients but one had severe micrognathia (n = 9). For group I (transport distraction osteogenesis), mean age was 6.8 years. and mean advancement was 28.5 mm. For group II (Matthews Device arthroplasty) mean age was 8.2 years, and mean advancement was 23.5 mm. In group I (transport distraction osteogenesis), mean incisor opening was 1 mm preoperatively and 27.5 mm postoperatively; however, it relapsed to 14.3 mm by 12.5 months follow-up (48% relapse). Mean incisor opening in group II (Matthews Device arthroplasty) was 3.9 mm preoperatively and 33.4 mm postoperatively and remained at 30.6 mm after 11.1 months follow-up (8% relapse). One patient in group I (transport distraction osteogenesis) underwent surgical revision because of relapse. Our data showed that for congenital TMJ bony ankylosis both transport distraction osteogenesis and Matthews Device arthroplasty techniques were successful initially; however, the Matthews Device arthroplasty avoided long-term relapse.