生长期山羊颅骨缝受牵张力作用后超微结构与免疫组化观察

目的研究生长期山羊颅骨冠状缝受牵张力作用后组织与细胞结构的变化。方法选用生长期山羊,在颅骨冠状缝两侧安放自行研制的牵张器。实验组动物按0.4mm/d的速率进行骨缝牵张。在牵张结束后第0,2和4周分3组取骨缝标本进行X线摄像,扫描电镜及BMP与TGF-β免疫组织化学观察。未进行骨缝扩张的动物作为对照。结果实验组动物的冠状缝均被成功分离。牵张结束后0与2周,扩大骨缝中可见胶原纤维沿牵张力方向有序排列,骨缝边缘出现大量成纤维细胞和成骨细胞,BMP和TGF-β在这些增殖活跃的细胞中呈高水平表达。第4周,受力骨缝边缘以膜内成骨方式进行改建,BMP和TGF-β阳性染色主要位于新生骨小梁四周的成骨细胞中。结论牵张成骨技术可以顺利扩张处于生长期动物的颅骨缝,BMP和TGF-β可能在颅骨缝牵张成骨过程中扮演重要调控角色。     

骨髓间充质干细胞移植对山羊颅骨骨缝牵张成骨的影响

目的研究自体骨髓间充质干细胞（MSCs）移植对生长期山羊颅骨冠状缝牵张后组织改建的影响。方法选用处于发育期山羊10只,随机分为实验组与对照组,各5只。在颅骨冠状缝两侧安放自行研制的牵张器,以每天0．4mm的速率进行骨缝牵张,连续加力8d。实验组动物骨缝牵张区给予注射自体骨髓间充质干细胞,对照组同期注射生理盐水。在牵张结束后第4周处死动物,取骨缝标本进行组织学和扫描电镜观察。结果所有实验动物的冠状缝均被成功牵开,骨缝边缘均可见新骨组织生成与改建。同对照组相比,实验组骨缝成骨与矿化较快,骨小梁分布密度及成熟程度也较高,骨缝形状已开始恢复正常。结论自体骨髓间充质干细胞移植对山羊颅骨缝牵张成骨可能有明显的促进作用。     

牵张成骨延长一侧下颌骨对颞下颌关节的影响

目的：研究牵张成骨（DO）延长一侧下颌骨对双侧颞下颌关节（TMJ）的影响。方法：用DO技术将8只山羊的一侧下颌骨延长10mm，在牵张完成后第8和16周分别处死4只动物，取双侧关节作组织学和扫描电镜研究。结果：下颌一侧DO术后双侧髁状突发生适应性改建，髁突表面超微结构正常。结论：在适当的牵张条件下延长一侧下颌骨不会对TMJ造成病理性损害。     

羊颧骨缝三维牵张成骨的组织学观察

目的探索不截骨的骨缝牵张成骨组织学变化。方法采用10～13个月龄普通山羊为实验对象，每只动物左颧骨行三维牵张成骨，固定1、3、5、8周后取材，和对侧空白对照标本比较，观察缝区组织变化、新骨形成情况。结果骨缝被牵开后1周，成纤维细胞、成骨细胞、毛细血管增生，大量纤维软组织排列有序并连接骨缝两侧，骨缝两侧组织面不整齐，牵张侧成骨活跃，大量类骨质形成；3周时形成较成熟的骨小梁；5周时编织骨形成；8周时结构成熟完整。结论不截骨的骨缝三维牵张成骨，骨缝牵张侧新骨快速形成；     

上颌骨复合体骨缝牵张的动物实验研究

目的探索颅颌面骨发育不足治疗新方法，采用骨缝牵张成骨技术刺激猴上颌骨诸骨缝再生，延长面中三分之一。方法实验选用猕猴6只，分为A（4岁）、B（4岁）、C（6岁）、D（8岁）4只，对照组E（5岁）、F（5岁）2只。相当于人类年龄的12．6～22．5岁。对应于人类青少年中后期与成熟期早期。于牵张前3月采用自行研制的前牵引支抗种植体行骨融合种植体植入术。部位为前鼻嵴下方牙槽突内及颧牙槽嵴上各植入两枚种植体。待骨融合后，麻醉状态下安放颅骨坚强外固定架。将NiTi—SMA螺簧连接于支抗种植体与固定架面具之间，进行牵张延长面中三分之一。采用力值为A，B猴500g，C猴800g，D猴1．200g。E，F不加力自然生长。牵引方向与牙A平面平行。牵张后4、8、10、12周分别取材。进行头颅标本与大体观察；模型测量；X线检查。结果实验组上颌骨均得到不同程度延长。结论不同年龄组实验动物可以通过骨缝牵张诱导缝区大量新骨形成，各缝因受力大小和方向不同而呈现多样性反应，牵张力值较大者形成的新骨多，加大牵引力值可使成年动物达到同样效果：前牵引支抗种植体能够承受实验所加力值。颅骨外固定坚强牵引牵张器具有稳定可靠的牵张作用。     

牵张成骨矫治腭裂的激光共聚焦荧光定量分析

目的：利用激光共聚焦显微镜与计算机辅助荧光定量分析，研究牵张成骨术矫治腭裂新骨生成随时间间期不同的动态变化趋势，为临床矫治腭裂应用提供理论与实验依据。方法：以家猫20只为实验对象。其中18只动物建立人工腭裂实验模型。实验组（动物15只）：应用牵张成骨术，以0．4mm×2次／d的速率牵张整复封闭其腭部组织缺损。术后第2、4、6、8及12周前6d以四环素肌注标记（30mg／kg）后各取材3只动物，标本制片后激光共聚焦显微镜观察荧光沉积并进行计算机定量分析，结果与实验对照组（动物3只）及空白对照组（动物2只）对比。结果：实验组不同时间间期标本的荧光强度平均值及其总量，显示出明确的动态变化规律，自2周组起，成骨活动明显活跃，到4周组达到顶峰，至8、12周组逐渐减弱，但仍显著高出无明显荧光沉积的空白和试验对照组。结论：应用牵张成骨术移动骨运送盘封闭组织缺损，牵张间隙逐渐被膜内成骨新骨生成修复，恢复了骨连续性。随时间间期的延长，新骨逐渐改建成熟。成骨活动呈现短期达到高峰后，逐步减弱的动态变化规律。     

牵张成骨延长山羊下颌骨后下齿槽神经的组织学变化

目的：研究下颌骨牵张成骨术后不同时间下齿槽神经的组织学改变。方法：对8只成年山羊行双侧下颌体骨皮质切开术,经口外安置自行研制的下颌牵张器,以每天1mm的速率向前牵引延长其中6只山羊的下颌骨10mm。于牵张结束后第2、4、8周各处死2只动物,取双侧下齿槽神经作组织学检查,另2只未牵张的山羊作对照。结果：下齿槽神经受牵张力作用发生了一定程的沃勒变性,主要表现为髓鞘肿胀、碎裂及轴索数目减少。但随着固定时间的延长,受损神经纤维逐渐得以再生。结论：下颌骨牵张成骨术后下齿槽神经发生了轻度的退行性变,但这种退行性变在适宜的速率牵张是可逆的。     

MSCs移植促进输送盘骨牵张术修复颅骨缺损的实验研究

目的 :研究自体骨髓间充质干细胞 (MSCs)对采用输送盘骨牵张术修复山羊颅骨缺损效果的影响。方法 :将成年雄性山羊 8只 ,随机分为A、B两组 ,每组 4只。在动物颅顶区制造全层颅骨缺损和输送盘 ,用自行研制的牵张器行输送盘骨牵张术修复颅骨缺损。牵张结束后 ,在A组动物牵张区注入体外培养的自体骨髓间充质干细胞 ;B组同期注入生理盐水作对照。在牵张结束后的第 4周处死A、B两组动物 ,取牵张区新生组织标本行组织学和扫描电镜分析。结果 :移植MSCs的A组动物牵张区新骨生成速度和钙化程度显著高于B组动物。结论 :局部移植MSCs可能有促进牵张成骨的作用。     

牵张成骨矫治腭裂动物模型新骨Ca、P元素能谱分析

目的应用牵张成骨术整复腭裂实验动物（猫）模型硬腭部骨质缺损的基础上，观察研究不同时间间期牵张区新生骨质的Ca、P元素含量的动态变化，并探讨新骨生成与改建的发展变化规律。方法家猫20只为实验对象。其中18只动物建立人工腭裂实验模型。实验组（动物15只）：应用牵张成骨术，以每；P-0.4mm的速度，每日两次的频率和恒定的方向整复其腭部软硬组织缺损，至裂隙完全封闭。于牵张术后第2、4、6、8及12周分别对3只动物施以安乐死，取标本测定Ca、P元素能量谱曲线并计算Ca、P元素质量比及原子计数比。结果与实验对照组（动物3只）及空白对照组（动物2只）对比。结果通过对新骨的Ca、P元素能量谱、Ca／P质量比及原子计数比的分析可将DO后的固定期分为三个阶段，即2周左右为新骨形成早期，4-6周为中期，8-12周时为后期，显示了新骨不断钙化成熟的趋势。结论牵张推移骨运送盘至健侧裂隙缘后，牵张间隙有规律地为新骨组织完全修复，最终恢复骨连续性且结构正常。DO新生骨组织显示了不断钙化成熟的趋势，证明D0的成骨活动未经过软骨中介体。     

改良双点牵张成骨术在下颌骨节段缺损修复中的应用

目的：探讨单一传送盘的两端牵张骨修复下颌骨节段缺损的可行性。方法：选用山羊6只，采用自行研制的下颌连续牵张器，经口外途径，将带牙传送盘两端进行顺序牵张成骨。结果：6只山羊的12—16mm长度下颌体的局段缺损被传送盘单端牵张修复，传送盘另一端再次牵张使下颌过度延长达到5mm左右，X线片示，缺损区和过度牵张区阻射情况良好，骨质连续性恢复；组织学显示牵张区有活跃新骨形成。固定6—8周，组织学和X线片可见新骨完全钙化，但改建仍未结束。结论：单一传送盘两端顺序牵张成骨修复下颌骨节段缺损是可行的。     

山羊双侧下颌骨牵引成骨动物模型的建立

目的:建立一个可行性良好的山羊下颌骨牵引成骨模型。方法:将6只山羊的下颌骨截断,安置牵引器,延迟期4 d后以0.5 mm/次,2次/d的速度牵引10 d;随后进入固定期。分别于固定期的2、4、6、8周处死动物,进行大体标本和放射学观察。结果:牵引过程被所有山羊耐受,牵引长度达到预期效果。结论:山羊是一种良好的牵引成骨动物模型;该模型有助于DO临床的应用及研究。     

不同速率牵张山羊下颌后下齿槽血管变化与血管生成的实验研究

目的:研究不同速率牵张延长山羊下颌骨后下齿槽动静脉的变化和新骨组织内血管生成情况。方法:8只成年山羊随机分为3组,A组(3只)以110 mm/d牵张,B组(3只)以210 mm/d牵张,C组(2只)为对照。A、B两组均牵张延长下颌10 mm,于牵张结束固定后第2周时处死动物,取牵张区下齿槽动静脉及新骨组织行组织学和定量组织学研究,观察下齿槽血管的管壁厚度和管径大小变化,以及新骨中微血管数量变化。结果:两种速率牵张后均未见下齿槽血管壁有病理性改变,但210 mm/d组的血管管径变小,管壁变薄,与对照组相比有显著差异(P<0105)。110 mm/d牵张后微血管密度较210 mm/d牵张后微血管密度高,且新生骨小梁更为成熟,其差异具有统计学意义(P< 0105)。结论:下颌骨牵张后下齿槽血管无明显变化,但快速牵张可能对牵张间隙内血管生成有不良影响。     

胶原海绵在下颌骨牵张成骨早期成骨中的作用

目的建立山羊双侧下颌骨牵张成骨动物模型,研究胶原海绵在山羊下颌骨牵张成骨早期成骨中的作用。方法将6只山羊的下颌骨截断,安置牵张器,延迟4d后以每次0.5mm、每天2次的速率连续牵张10d,随后进入固定期。于固定期2、4、6、8周处死动物,行大体标本、X线观察,骨密度、骨矿物质质量测定,苏木精-伊红染色后的组织形态学观察。结果牵张过程被所有山羊耐受,下颌骨牵张长度达到预期效果。加入胶原海绵的实验侧牵张区新骨早期成骨效果明显好于同期的对照侧。结论山羊是一种良好的牵张成骨动物模型。胶原海绵可加速牵张区新骨早期成骨,缩短牵张成骨的固定期。     

牵张成骨延长山羊下颌骨后下齿槽神经的组织学变化

目的 :研究下颌骨牵张成骨术后不同时间内下齿槽神经的组织学改变。方法 :对 8只成年山羊行双侧下颌体骨皮质切开术 ,经口外安置自行研制的下颌牵张器 ,以每天 1mm的速率向前牵引延长其中 6只山羊的下颌骨10mm。于牵张结束后第 2、4、8周各处死 2只动物 ,取双侧下齿槽神经作组织学检查 ,另 2只未牵张的山羊作对照。结果 :下齿槽神经受牵张力作用发生了一定程度的沃勒变性 ,主要表现为髓鞘肿胀、碎裂及轴索数目减少。但随着固定时间的延长 ,受损神经纤维逐渐得以再生。结论 :下颌骨牵张成骨术后下齿槽神经发生了轻度的退行性变 ,但这种退行性变在适宜的速率牵张下是可逆的     

Changes in the inferior alveolar nerve after mandibular lengthening with different rates of distraction.

PURPOSE: This study investigated the changes in the inferior alveolar nerve after mandibular lengthening with different rates of distraction. MATERIALS AND METHODS: Bilateral mandibular corticotomies were performed in 8 goats. The mandibles in 6 goats were lengthened 10 mm using a custom-made distractor with 2 different rates of distraction (1 mm/d [n = 3] and 2 mm/d [n = 3]); the other 2 nondistracted mandibles served as a control. The goats with distracted mandibles were killed at 2 weeks after completion of distraction. The inferior alveolar nerve specimens from all animals were harvested and processed for histologic and ultrastructural evaluation. RESULTS: The mandibles were lengthened successfully in the distracted animals. Morphologic changes in the inferior alveolar nerves were observed when compared with the nondistracted controls. Moreover, signs of nerve degeneration, such as demyelination, axonal swelling, axoplasmic darking, and decrease in the number of axons, were more extensive and prominent in those nerves distracted at a rate of 2 mm/d. CONCLUSIONS: Degenerative changes in the inferior alveolar nerve occur after mandibular lengthening by distraction osteogenesis. The distraction rate of 1 mm/d appears to be tolerable and safe for the inferior alveolar nerve, but rapid distraction may cause serious degeneration.     

Differences in mandibular distraction osteogenesis after corticotomy and osteotomy

Corticotomy or osteotomy was performed on opposing sides of the mandibles in 18 goats. A custom-made distractor was used to lengthen the mandible at a rate of 1 mm/day for 10 days (total 10 mm elongation). Six goats were sacrificed respectively at 2, 4 and 8 weeks after completion of distraction. The distracted calluses were harvested and processed for radiographic, histologic, and scanning electron microscopic evaluation as well as Ca/P ratio analysis. The regenerate bone in the corticotomy side showed more bone formation and earlier mineralization than in the osteotomy side. The results of this study suggest that preservation of intramedullary vessels is beneficial to bone regeneration following mandibular osteodistraction, and that performing corticotomy may be a simple but effective way to promote the maturity of the distracted callus and shorten the time for fixation.     

Coronal suture response to distraction osteogenesis in rabbits with delayed-onset craniosynostosis.

Recent studies have identified a subpopulation of persons with craniosynostosis who exhibit progressive or delayed-onset synostosis and mild cranial vault deformities. These persons may be good candidates for nonextirpation distraction osteogenesis. The present studies were designed to determine force-displacement parameters and assess the effects of distraction osteogenesis on coronal suture growth and morphologic characteristics in a rabbit model with congenital, delayed-onset craniosynostosis. Data were collected from a total of 178 rabbits: 71 normal controls; 16 normal controls with distraction; 72 with delayed-onset coronal suture synostosis; and 19 with delayed-onset coronal suture synostosis and distraction. At 10 days of age, all rabbits had amalgam markers placed on both sides of the coronal suture. In the force-displacement study, force-displacement distractors were placed across the coronal suture and distracted acutely for 1.0 mm at 42 days of age. Force-displacement curves for the coronal suture were best described by a third-order polynomial regression equation for both normal and synostosed groups. Significant differences (P < 0.05) were found in the mean force necessary to distract a normal suture 1 mm in distance (13.72 kg) compared with a suture with delayed-onset synostosis (48.39 kg). A significant (P < 0.05) relationship was also found between the extent of synostosis and the distractive force in rabbits with delayed-onset synostosis. In the distraction study, internal distractors were fixed across the coronal suture at 25 days of age and percutaneously and intermittently activated at an average of 0.11 mm/day for 42 days (4.54 mm total). Serial radiographs were taken at 10, 25, 42, and 84 days of age. Results revealed that rabbits with delayed-onset synostosis and distraction had significantly (P < 0.01) more coronal suture growth rates compared with rabbits with delayed-onset synostosis and no distraction. Coronal sutures were harvested at 84 days of age for qualitative histologic examination. Normal, distracted coronal sutures showed widened sutural ligaments and thin, active osteogenic fronts. In contrast, distracted coronal sutures from rabbits with delayed-onset synostosis showed narrowed sutural ligaments, thickened and blunt osteogenic fronts, and increased collagen and bony matrix deposition compared with controls. Results suggest that distraction osteogenesis without corticotomy may be a treatment alternative in persons with progressive, delayed-onset synostosis. However, these preliminary data also suggest that distractive forces may accelerate or stimulate osteogenesis differentially in persons with craniosynostosis, possibly through an underlying genetic disorder of bone and cytokine regulation. These differential osteogenic responses to distraction, if validated clinically, will need to be taken into account when planning distraction rate and rhythm protocols for patients with craniosynostosis.