激活素A在兔下颌骨牵张中表达的实验研究

目的　探讨激活素A在下颌骨牵张中的作用。方法　将兔下颌骨牵张末期新生组织分为 3个带 ,用免疫组化方法对不同带中激活素A表达情况做半定量研究。结果　中间纤维带成纤维细胞、纤维组织激活素A染色为阴性 ,矿化前带成骨细胞及细胞外基质激活素A强阳性 ,外围新骨带成骨细胞、骨细胞激活素A染色也较广泛 ,各组之间存在显著性差异。结论　在下颌骨牵张过程中激活素A表达增高 ,可能对牵张过程中成骨细胞分泌、继续向骨细胞分化、骨组织形成均起重要的促进作用     

兔双侧下颌骨牵引成骨动物模型的建立

目的:使用CBX01-15型兔下颌骨专用牵引器,建立兔双侧下颌骨牵引成骨动物模型,并评价其牵引效果。方法:新西兰大白兔8只,行双侧下颌骨截骨术,安置牵引器。延迟5天后,两侧下颌骨均以0.5mm/次,2次/天的速度牵引15天,牵引结束后固定8周,新骨分别行大体、放射学和组织学检查。结果:所有动物均良好耐受牵引及固定,未发生死亡,双侧下颌体均显著延长。固定8周时,两侧新骨均接近正常骨。结论:兔双侧下颌骨牵引成骨动物模型牵引效果可靠,新骨再生良好。     

Mechanobiology of mandibular distraction osteogenesis: finite element analyses with a rat model.

Three-dimensional finite element (FE) analyses were performed to characterize the local mechanical environment created within the tissue regenerate during mandibular distraction osteogenesis (DO) in a rat model. Finite element models were created from three-dimensional computed tomography image data of rat hemi-mandibles at four different time points during an optimal distraction osteogenesis protocol (i.e., most successful protocol for bone formation): end latency (post-operative day (POD) 5), distraction day 2 (POD 7), distraction day 5 (POD 10), and distraction day 8 (POD 13). A 0.25 mm distraction was simulated and the resulting hydrostatic stresses and maximum principal tensile strains were determined within the tissue regenerate. When compared to previous histological findings, finite element analyses showed that tensile strains up to 13% corresponded to regions of new bone formation and regions of periosteal hydrostatic pressure with magnitudes less than 17 kPa corresponded to locations of cartilage formation. Tensile strains within the center of the gap were much higher, leading us to conclude that tissue damage would occur there if the tissue was not compliant enough to withstand such high strains, and that this damage would trigger formation of new mesenchymal tissue. These data were consistent with histological evidence showing mesenchymal tissue present in the center of the gap throughout distraction. Finite element analyses performed at different time points during distraction were instrumental in determining the changes in hydrostatic stress and tensile strain fields throughout distraction, providing a mechanical environment rationale for the different levels of bone formation in end latency, and distraction day 2, 5, and 8 specimens.     

下颌骨单侧牵张成骨对颞下颌关节的影响

目的:研究下颌骨单侧牵张成骨对颞下颌关节的影响。方法:新西兰大白兔25只,24只行单侧下颌牵张,随机分为两组:一组牵张速率为0.5mm×2次/天(1mm组);另一组为0.5mm×4次/天(2mm组),间歇期均为5天,牵张长度均为10mm。在牵张完成后0周、2周、4周、8周每组各处死3只动物,最后1只处死做对照,4%多聚甲醛灌注固定,取双侧关节盘和髁状突,做大体观察及组织学观察。结果:牵张后大体观察可见关节盘无显著形态异常,髁状突有不同程度适应性改建;组织学主要表现为关节盘不同程度中带变薄,纤维走行改变,血管侵入,后带变厚;髁状突表现为纤维软骨组织形态学的改变和软骨、骨的改建活动,2mm/日组可见破坏现象发生。结论:颞下颌关节有很强的改建能力,在合适的牵张速度下可通过发生适应性改建,使髁状突在形态和结构上适应新的位置和环境,从而继续行使正常关节功能。     

Locally injection of cell sheet fragments enhances new bone formation in mandibular distraction osteogenesis: A rabbit model

Effective methods to shorten the treatment period of distraction osteogenesis (DO) are needed. To investigate whether injections of osteogenic bone marrow stromal cell (BMSC) sheet fragments could be used to facilitate new bone formation during DO, 30 rabbits underwent bilateral mandibular osteotomy and their mandibles were lengthened at a rate of 0.75 mm/12 h for 6 days after a 5‐day latency period. There were three treatment groups (n = 10 for each group): Serum‐free medium, dissociated BMSCs, and BMSC sheet fragments. A local injection was conducted with a needle directly into the distracted areas immediately after distraction. Rabbits were sacrificed for examination at 3 and 6 weeks after injection. Gross examination, radiographic evaluation, and micro‐CT scanning indicated a significant increase in bony union in the BMSC sheet fragment group, compared with the medium group and the dissociated cell group. The histomorphometric analysis showed more intensive bone formation in the sheet fragment group than the other two groups at each time point. Additionally, the peak load was significantly higher in the fragment group than those in the others. The results show that injection of BMSC sheet fragments promotes bone formation in DO and indicate a promising approach to shorten the treatment period of osteodistraction. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1082–1088, 2013     

下颌骨单侧牵张成骨对下牙槽神经的影响

目的:研究下颌骨单侧牵张成骨对下牙槽神经的影响。方法:新西兰大白兔25只,24只行单侧下颌牵张,随机分为两组:一组牵张速率为0.5mm×2次/天(1mm组);另一组为0.5mm×4次/天(2mm组),间歇期均为5天,牵张长度均为10mm。在牵张完成后0周、2周、4周、8周时每组各处死3只动物,最后一只处死做对照。4%多聚甲醛灌注固定,取牵张区含下牙槽神经组织块做大体观察及组织学观察。结果:牵张区神经大体观察均可见直径变细,组织学上可见发生了不同程度的退行性变化,表现为髓鞘肿胀、层状分离和断裂、轴索数目减少,但神经外膜、束膜仍完整,随着时间延长,发生修复性变化。结论:下颌骨牵张成骨后下牙槽神经发生退行性变,但在合适的牵张速率下是可逆的,随时间延长可以完全修复。     

Osteogenesis and mineralization in a rabbit mandibular distraction osteogenesis model is promoted by the human LMP‐1 gene

To observe the effects of LIM mineralization protein‐1 (LMP‐1) on bone regeneration in the distraction zone based on gene transduction, 36 New Zealand white rabbits underwent mandibular lengthening with a distraction rate of 2 mm/day. The animals were then randomly divided into group A and group B (n = 18, each). At the end of the distraction, Ad5‐EGFP viruses and Ad5‐LMP‐1/EGFP viruses were injected into the distraction gaps in groups A and B, respectively. Seven days later, five randomly selected animals from each group were sacrificed to evaluate the survival of the virus. Four and 8 weeks after distraction osteogenesis (DO), six samples randomly selected from each group underwent CT scanning and dual energy X‐ray absorptiometry detection. Eight weeks after DO, the rabbits were sacrificed, and the distracted mandibles were harvested. Six animals from each group processed for radiography, micro‐CT, histology, and the rest samples were taken three‐point bend testing. Using this model, better bone formation and mineralization in the distracted callus were observed in group B when compared with those in group A. The results suggest local transduction with LMP‐1 gene promotes osteogenesis and mineralization in DO. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:521–526, 2015.     

Expression of osteotropic growth factors and growth hormone receptor in a canine distraction osteogenesis model

Osteotropic growth factors play an important role in bone metabolism. Nevertheless, knowledge about their expression in relation to distraction osteogenesis remains limited. The aim of the present study was to determine the expression of growth hormone (GH), growth hormone receptor (GHR), insulin-like growth factor I (IGF-I), insulin-like growth factor II (IGF-II), and bone morphogenetic protein 2 (BMP-2) in distraction-induced bone regeneration. Expression of these factors was assessed during the consolidation phase, comparing distraction osteogenesis with osteotomy-induced bone formation. Real-time PCR was performed as a semiquantitative measurement of mRNA, and the relative expression levels of these factors were determined. In addition, plasma GH profiles and plasma concentrations of IGF-I, IGF-II, and insulin-like growth factor-binding protein 4 and -6 (IGFBP-4 and -6) were measured to assess their potential systemic role during bone formation. Expression of GHR, IGF-I, and BMP-2 had significantly increased in comparison with the expression of these factors in mature bone. Expression of GHR was significantly higher in distraction-induced bone regenerate than in osteotomy-induced bone. No significant differences were found for the expression of IGF-I and BMP-2 between distraction and osteotomy. Plasma concentrations of GH, IGF-I, IGF-II, IGFBP-4, and IGFBP-6 did not demonstrate any significant differences between treatment groups and controls. Upregulation of GHR expression in distraction osteogenesis may enhance sensitivity to endogenous systemic GH and thus promote consolidation of the regenerated bone. Changes in the systemic osteotropic growth factors GH, IGF-I, IGF-II, IGFBP-4, and IGFBP-6 do not seem to be of importance during distraction osteogenesis.     

Locally applied nerve growth factor enhances bone consolidation in a rabbit model of mandibular distraction osteogenesis.

Distraction osteogenesis is widely used in treating deformities, defects, and fractures of both long bones and craniofacial bones. Demands for acceleration of bone consolidation are increased in distraction osteogenesis. Nerve growth factor (NGF) can enhance innervation and bone regeneration in a fracture model and stimulate differentiation of osteoblastic cells. In this study, we tested the ability of locally applied NGF to enhance bone regeneration in a rabbit model of mandibular distraction osteogenesis. Twenty rabbits underwent bilateral distraction osteogenesis with a rate of 0.5 mm per 12 h. Two times 0.04 mg human NGFbeta (hNGFbeta) in buffer was injected into the callus after distraction. The contralateral side received placebo injections. Rabbits were euthanized at consolidation times of 14 and 28 days. Specimens were subjected to radiography, callus dimensions measurement, mechanical testing, and bone histological and histomorphometric analysis. The maximum load, bone volume/total volume, mineral apposition rate of the 1st to 11th day, and mineralized bone percentage were significantly higher in the hNGFbeta side at 14 and 28 days (p<0.05). The data indicate that locally applied hNGFbeta can accelerate callus maturation and may be an option to shorten the consolidation period in distraction osteogenesis.     

Sclerostin antibody enhances bone formation in a rat model of distraction osteogenesis

Neutralizing monoclonal sclerostin antibodies are effective in promoting bone formation at a systemic level and in orthopedic scenarios including closed fracture repair. In this study we examined the effects of sclerostin antibody (Scl‐Ab) treatment on regenerate volume, density, and strength in a rat model of distraction osteogenesis. Surgical osteotomy was performed on 179 Sprague Dawley rats. After 1 week, rats underwent distraction for 2 weeks, followed by 6 weeks for consolidation. Two treatment groups received biweekly subcutaneous Scl‐AbIII (a rodent form of Scl‐Ab; 25 mg/kg), either from the start of distraction onward or restricted to the consolidation phase. These groups were compared to controls receiving saline. Measurement modalities included longitudinal DXA, ex vivo QCT, and microCT, tissue histology, and biomechanical four‐point bending tests. Bone volume was increased in both Scl‐Ab treatments regimens by the end of consolidation (+26–38%, p < 0.05), as assessed by microCT. This was associated with increased mineral apposition. Importantly, Scl‐Ab led to increased strength in united bones, and this reached statistical significance in animals receiving Scl‐Ab during consolidation only (+177%, p < 0.01, maximum load to failure). These data demonstrate that Scl‐Ab treatment increases bone formation, leading to regenerates with higher bone volume and improved strength. Our data also suggest that the optimal effects of Scl‐Ab treatment are achieved in the latter stages of distraction osteogenesis. These findings support further investigation into the potential clinical application of sclerostin antibody to augment bone distraction, such as limb lengthening, particularly in the prevention of refracture. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1106–1113, 2018.

     

Reconstruction of segmental mandibular defects by distraction osteogenesis for mandibular reconstruction

BACKGROUND: Distraction osteogenesis is an established technique for the lengthening of long bones and correction of selected craniofacial deformities. Regenerate osteoid bone matrix formed during the distraction phase is malleable and can recreate the three-dimensional form of native bones. Animal experiments and early clinical experience have confirmed that distraction osteogenesis can be used for the reconstruction of segmental bony defects. Herein we discuss the principles of distraction osteogenesis in reference to reconstruction of segmental bony defects and report its clinical application of the mandible continuity defects. PATIENTS AND METHODS: Four patients (age, 7-83 years) with critical segmental mandibular defects (range, 3.5 cm-6.5 cm), resulting from ablative oncologic head and neck surgery underwent primary mandibular reconstruction by transport distraction osteogenesis. Two defects were at the angle and body region, one at the body, and the other at the parasymphysis and body region. Synthes Titanium Multi-vector and Leibinger Multi-guide distractors in bifocal (n = 2) and trifocal (n = 2) architecture were used after the stabilization of the segmental continuity defect using a defect-bridging mandibular reconstruction plate. Osteodistraction was carried out at a rate of 1 mm per day, with once or twice a day rhythm, after a 1-week latency period. The consolidation period was equal to the period of distraction. RESULTS: All patients tolerated the distraction procedure. Satisfactory bone formation was observed in two patients, and partial bone formation was seen in one patient. Treatment failure was encountered in one patient who had a second oral cavity primary tumor observed during the consolidation period, requiring interruption of the treatment sequence. CONCLUSIONS: Mandibular reconstruction with distraction osteogenesis is a potentially useful technique in selected patients with segmental mandibular continuity defects after ablative head and neck cancer surgery.     

Radiographic classification of osteogenesis during bone distraction.

Successful limb lengthening requires serial radiological evaluation of the progression of healing of the regenerate bone. However, there is no radiographic classification system that shows how the regenerate should progress during treatment in adults. The study aimed to address this need.A series of radiographs were studied from 92 patients (125 segments) who had undergone bone lengthening. A radiographic classification of osteogenesis was developed based on callus shape and radiographic features that occur between osteotomy and fixator removal.This classification system used both shape and type of feature to condense and record the radiographic information, but type of feature alone was sufficient to predict outcome. The concurrence and reproducibility of the classification system was tested by inter- and intra-observer studies. The degree of consistent repetition and agreement between observers suggests that the classification system is reliable, reproducible, and therefore should be robust in use.This classification system provides an insight into osteogenesis; it allows the progress of the bone healing to be assessed against a successful pattern of healing. Hence, potential problems can be predicted and clinical changes made to improve outcome. The classification can be simplified to make it more appropriate for clinical use.     

骨牵张技术治疗下颌骨获得性畸形

目的：探讨用骨牵张成骨技术治疗下颌骨获得性畸形的方法和经验，方法：7例因下颌骨创伤或肿瘤切除后遗留下颌骨畸形患者，采用新型内置式骨牵开器进行骨牵开术，术后潜伏期为7天，牵引节律为1mm／天，2次／天，牵引结束后固定6—8周。结果：7例患者的咬合关系和面形均得到理想恢复，最大牵张距离为3cm，最小距离为9mm，伤口无并发症。结论：骨牵引延长技术可以很好地适用于下颌骨骨折错位愈合或骨缺损患者，尤其适用于软组织不足，不易覆盖植骨的患者，此外，不需要另取自体骨移植。     

Gradual reduction of distal radial malunion using distraction osteogenesis

PURPOSE: To evaluate gradual distraction lengthening or distraction osteogenesis as a technique for treating malunions of the distal radius. METHODS: Twenty patients with clinical and radiographic evidence of distal radius malunion were treated with osteotomy of the distal radius using distraction osteogenesis. At the follow-up evaluation each patient was evaluated for healing rates, complications, resolution of pain, and radiographic alignment. Surgical treatment consisted of an application of a nonbridging external fixator that could be distracted to correct the deformity. A loosely set screw that connected the distal pins to the fixator served as a hinge and allowed the distal radius to rotate into a corrected position. Gradual distraction via distraction osteogenesis was initiated 1 week after surgery. RESULTS: Seventeen osteotomies healed uneventfully in an average of 9 weeks. Complications included 9 pin track infections. Two nonunions required bone grafting. One patient inadvertently compressed rather than distracted the fixator, leading to premature healing of the osteotomy. One patient ruptured the extensor pollicis longus. All complications resolved with additional intervention. Overall the patients showed radiographic and symptomatic improvement. CONCLUSIONS: An external fixator and distraction lengthening through distraction osteogenesis is a viable alternative to plate fixation and bone grafting. In 18 of 20 of our patients, the technique eliminated the need for bone grafting and the need for a second surgical procedure to remove a dorsal plate.     

前颌中缝牵张修复牙槽裂的实验研究

目的　探索用缝牵张成骨技术以组织再生的原理修复牙槽裂。方法　采用犬牙槽裂模型 ,牙槽裂形成术后 2周 ,于前颌中缝处安置缝牵张器 ,外张力 2 0 0g。牵张 2～ 3周 ,裂隙侧的前颌骨向侧方移动贴紧远中裂缘 ,用局部黏骨膜瓣修复牙槽裂隙。保持 2周后去除缝牵张器。临床观察、连续X线、头颅干骨和组织学检查评价治疗结果。结果　所有对照动物形成规则的牙槽裂 ,无自发骨性愈合。前颌中缝牵张后 ,裂隙侧前颌缓慢向裂侧上颌靠拢 ,2～ 3周与远中裂缘密切贴合。X线片示前颌中缝呈现由窄渐宽的三角形 ,三角形的尖端指向后方 ,三角区域的骨密度逐渐增加。骨膜成形术后 3个月 ,原牙槽嵴缺损处骨质连续性完全恢复 ,且牙槽骨段在三维方向上均与对侧相同。前颌中缝恢复正常直线形态。结论　该牙槽裂模型稳定性和重复性好 ;前颌中缝牵张诱导缝区新骨形成 ,一侧前颌向裂隙移位和局部骨膜成形可达到完善的牙槽裂修复。     

电穿孔介导的基因治疗兔下颌骨牵引成骨模型的建立

目的 探讨电穿孔技术介导的重组质粒体内转染兔下颌骨牵引成骨的可行性.方法 以新西兰大白兔为实验动物模型,于术后3 d开始下颌骨牵引,每天0.8 mm,连续牵引7 d后,将实验动物分为3组:质粒+电穿孔组(A组),质粒组(B组),生理盐水组+电穿孔组(C组).各组动物分别于注射后3 h及1、3、7、14 d处死,切取牵引区组织0.4 cm×0.4 cm行冰冻切片检查,采用荧光显微镜观察绿色荧光蛋白(GFP)表达以检测外源基因的表达.检测兔血清肝功能指标丙氨酸转氨酶(ALT)、天门冬氨酸转氨酶(AST)和肾功能指标尿素氮(BUN)、肌酐(Scr)和心、肝、肾组织学检查.结果 A组转染新西兰大白兔,3 h可观察到GFP的表达,1 d时GFP的表达增强,3 d时GFP的表达最强,其后开始逐渐下降,7 d后GFP的表达减少,14 d仍可观察到微弱GFP的表达.B组的GFP的表达时限与A组相同,但各时相点的GFP的表达强度明显弱于A组,C组在各时间段均未观察到GFP的表达.3组肝、肾功能指标两两比较差异无统计学意义(P>0.05).结论 电穿孔技术介导的带有荧光标记的重组质粒体内转染,可在兔下颌骨牵引区组织内表达,电穿孔能明显提高重组质粒的体内转染效率,提示电穿孔技术介导的重组质粒体内转染兔下颌骨牵引成骨的动物模型是可行的,用于体内试验是安全的.     

经缝牵引成骨早期矫正儿童面中份发育不全

目的 临床探索经缝牵引、均衡前移面中份骨骼，早期矫治面中份发育不全的新技术新方法。方法 选择6～12岁面中份发育不全的患儿，采用弹性外牵引装置矫正面中份发育不全。牵引系统由经鼻孔插入的骨承力牵引装置、面弓和牙科正畸用的橡皮圈组成。全麻下于梨状孔外下缘的外侧钻孔，通于下鼻道的前部；或在硬腭的前部钻孔，穿透鼻底。经鼻孔将骨牵引承力装置插入梨状孔缘或鼻底的骨孔内。手术后第1～2天用连接于面弓和骨牵引装置的正畸橡皮圈进行牵引。牵引力为600～1200g，随骨骼移动的进度不断调整。骨骼移动达到预定的位置后，减小牵引力维持牵引。结果 临床治疗9例患儿。面中份骨骼移动均衡。患者面容和咬合关系完全恢复正常。面部侧面观显示上、中、下各部分协调匀称，眶下、颧部和上唇部丰满，鼻背挺拔。结论中位缝牵引技术能够早期有效地矫正面中份畸形，骨骼前移均衡，且方法简便，损伤小。     

牙槽骨牵张成骨术在犬牙齿快速移动过程中的实验研究

目的：观察牙槽骨牵张成骨术在正畸牙齿快速移动过程当中,移动牙与支抗牙的牙周及牙髓组织改变。方法：杂种犬6只,拔除下颌第二前磨牙后,随机选取一侧为实验侧,进行外科减阻游离手术后,粘结自制牵引装置;另一侧为对照侧则以传统方法牵引下颌第一前磨牙向远中。结果：实验侧移动牙与支抗牙牙周及牙髓组织未发生可逆性改变,移动牙与下颌尖牙间离断处牙槽骨有大量新生成骨细胞。结论：牙槽骨牵张成骨术也是一种使正畸牙齿快速移动的有效方法。