胫骨牵引成骨过程中骨形态形成蛋白4及其受体的表达*☆

背景：骨形态形成蛋白4及其受体在骨再生和修复过程中起着重要的作用,但具体机制尚不清楚。 目的：建立小鼠胫骨牵引成骨模型,分析骨形态形成蛋白4及其受体在牵引成骨过程中的表达,探讨机械牵张力转化为生物信号从而调节骨再生过程的机制。 方法：健康雄性8周龄CD-1小鼠36只,按照手术时间随机分成术后第5,9,13,17,24和31天组,每组6只。所有小鼠均接受左胫骨中上段低能截骨,安置体外延长固定架,截骨后5 d为静止期;截骨后第6天起开始每天进行胫骨延长,速率为0.2 mm,2次/d,共12 d,为牵引期;自第18天停止牵引,为固塑期。于术后第5,9,13,17,24和31天分别处死动物,采集胫骨标本,作组织学检查、RT-PCR和原位杂交实验分析骨形态形成蛋白4及其受体激活素样激酶3以及骨钙素的表达。 结果与结论：组织学检查显示静止期修复过程基本与骨折愈合过程相似。小鼠骨折断端在持续牵引下有明显的骨痂形成,骨形态形成蛋白4及其受体激活素样激酶3以及骨钙素的mRNA的表达明显增强。结果表明,牵引成骨是一种持续的骨再生过程,机械张力可通过刺激骨形态形成蛋白4及其受体以及骨钙素的持续高表达维持骨痂的不断形成和再塑,以充填连续延长的骨折间隙。     

内置式下颌骨牵引成骨术及其常见并发症的处理

目的 探讨内置式下颌骨牵引成骨术的常见术后并发症发生的原因及防治措施。方法 总结分析1997至2004年采用内置式下颌骨牵引成骨术治疗下颌骨畸形或缺损患者46例61侧，其中半侧颜面短小27例，下颌骨发育不足或小颌畸形双侧8例、单侧4例，电击伤或肿瘤术后缺损畸形3例，Treaeher Colins综合征2例，睡眠呼吸暂停综合征2例。结果 46例61侧发生并发症者9例，包括牵引机械装置故障3例，局部感染2例，前牙开骀2例，皮肤窦道2例。经积极处理后均达到预期治疗目的。结论 减少下颌骨牵引成骨术并发症的关键在于充分理解下颌骨牵引成骨术的机理，熟悉掌握下颌骨及邻近解剖结构，操作规范熟练，充分的术前准备和术后处理尤为重要。     

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。     

牙槽嵴裂隙间固定对腭裂上颌复合体内置式牵引成骨生物力学的影响

目的 探讨裂隙间固定对唇腭裂上颌复合体牵引成骨生物力学的影响.方法 采用三维有限元方法,建立唇腭裂上颌复合体LeFort Ⅰ型截骨骨块及相应软组织有限元模型,在保留牙槽嵴裂隙与裂隙两侧钛板固定两种情况下,模拟临床上内置式牵引方式,使截骨块上牵引器固位点沿牵引方向前移10 mm,比较分析其生物力学变化.结果 唇腭裂上颌复合体LeFort Ⅰ型截骨内置式牵引下,腭部出现压缩现象,而裂隙两侧钛板固定腭部压缩现象不明显.矢向位移与垂直向位移在两种工况下比较,位移方向及大小与保留裂隙的前牵引无明显差异.结论 裂隙间固定后唇腭裂上颌复合体内置式牵引成骨,可以避免腭部出现压缩现象,有生物力学指导意义.     

山羊下颌骨牵张成骨术的实验研究

目的明确牵张成骨的骨形成过程及机制，为进一步的深入研究奠定实验基础。方法选取8只3月龄健康幼年山羊，建立下颌骨牵张成骨术的实验动物模型，成模后动物随机分为4组，每组2只，第1组动物在牵张完成后1周处死，第2组在牵张完成后2周处死，第3组在牵张完成后4周处死，第4组在牵张完成后6同处死。对新生骨的组织学、影像学及骨密度的变化进行观察。结果所有动物的右下颌骨均延长了大约10mm，组织学证实牵张区确有新骨形成。随着固定期时间的延长，X线检查和骨密度测试结果显示新骨组织中骨密度逐渐增高。牵张器相接触一侧的新生骨的骨质成骨较差。结论山羊是一种较理想的对牵张成骨进行模拟性研究的实验动物，采用与牵张方向一致的牵张器施力方向可以避免侧向力的产生，从而提高术后成骨质量。     

颅骨牵张术中新骨骨密度的定量评价

目的:探讨颅骨牵张术修复骨缺损过程中新骨骨密度的评价方法。方法:成年健康山羊18只,颅顶区制备25mm×10mm全层颅骨缺损,随机分为实验组和对照组,实验组15只建立牵张术修复颅骨缺损的动物模型,于牵张结束后2,4,6周分别处死5只动物,对照组3只动物与实验组牵张后6周动物同期处死,QCT、DEXA两种方法测量新骨骨密度,比较两种测量方法骨密度值(BMD)及相关性。结果:实验组QCT测量牵张间隙各兴趣区BMD值较前一时段对应BMD值明显增加(P<0.05),同一牵张间隙内各固定时段两端(R2、R3)较中央(R1)BMD值明显高(P<0.05),R2、R3之间无明显差别(P>0.05);DEXA测量固定期4周,各兴趣区BMD值较固定2周对应BMD值明显增加(P<0.05),而固定期6周,仅牵张间隙中央(R1)较固定4周对应BMD值增加有统计学意义(P<0.05),同一牵张间隙内固定期2,4周两端(R2、R3)较中央(R1)BMD值明显高(P<0.05);两种检测方法测得平均骨密度值在各时段均存在正相关(P<0.005);对照组缺损区QCT、DEXA检测未显示有新骨形成。结论:两种检测方法均能反映牵张过程新骨骨密度变化,QCT不受解剖结构和牵张器形状的影响,更适于颅面骨牵张术新骨形成的监测评价。     

Correction of Lower Limb Deformities Using Ilizarov's Technique

Background

India accounts for approximately 10 million orthopaedically handicapped children and adults with limb deformity. Ilizarov ring fixator could treat most of these deformities.

Methods

Twenty cases of deformities of lower limb managed with Ilizarov technique during period between March 2001 and February 2003 were studied.

Results

55% were in the age group of 11-30 years. Out of the 20 cases studied, 6 were congenital talipes equino varus, 8 were fixed flexion deformity of knee, 4 were equines deformity of the ankle and 2 were malunited fracture shaft of tibia.4 patients who had recurrence were operated for fixed flexion deformity of the knee. The main complication encountered was pin tract infection, which was seen in 15(75%) cases. In 16(80%) cases, the results were excellent with no recurrence of deformity and patients were able to walk independently. In 4 (20%) cases, recurrence was mild to moderate (10 to 20) but all of them were able to ambulate idependently and carry out their routine activities.

Conclusion

Ilizarov ring fixator is a superior compared to conventional methods for correction of deformities of lower limb.Key Words: Ilizarov method, Ligamentotaxis, Distraction     

The molecular biology of distraction osteogenesis

Distraction osteogenesis has become a mainstay in bone engineering and the recent application of this technique to the membranous craniofacial skeleton has significantly improved our armamentarium for reconstructive craniomaxillofacial procedures. However, if the biomechanical, histological and ultrastructural changes associated with distraction osteogenesis have been widely described, the molecular mechanisms governing the formation of new bone in the interfragmental gap of gradually distracted bone segments remain largely unclear. Recently, our laboratory has described a rat mandibular distraction model that provides an excellent environment for deciphering the molecular mechanisms that mediate distraction osteogenesis. In this Article, we present the hypotheses and current research that have furthered our knowledge of the molecular mechanisms that govern distraction osteogenesis. Recent studies have implicated a growing number of cytokines that are intimately involved in the regulation of bone synthesis and turnover. The gene regulation of numerous cytokines (Transforming Growth Factor-B, Bone Morphogenetic Proteins, Insulin-like Growth Factor-1, Fibroblast Growth Factor-2) during distraction osteogenesis have been best characterized and will be discussed in this text. We believe that novel systems like the rat model will facilitate our understanding of the biomolecular mechanisms that mediate membranous distraction osteogenesis and will ultimately guide the development of targeted-strategies designed to accelerate bone healing.     

Indication for and surgical outcomes of the distraction method in various types of craniosynostosis

Background Various surgical techniques for the treatment of craniosynostosis using distraction devices have been described over the last few years and we have applied these procedures in seven patients with varying types of craniosynostosis. The aim of this report is to clarify the advantages and disadvantages of these surgical methods and to discuss current concepts for the surgical strategy in the treatment of craniosynostosis.Material and methods From January 2001 to March 2003, 25 patients with craniosynostosis were examined. Among them, 7 patients, 5 with Apert syndrome, 1 with Crouzon disease, and 1 with multiple-synostosis, underwent surgical treatment using the distraction method with internal distraction devices, according to our treatment strategy for craniosynostosis. All patients underwent preoperative and postoperative evaluations, which included the patients neurological state, developmental quotient (DQ), and three-dimensional CT (3D-CT).Results The timing of the procedures undertaken was between the ages of 1 year 5 months and 12 years 6 months (mean age 4 years 11 months). Five patients had received previous treatment and this procedure was used as a secondary operation. Postoperative distraction distances varied from 7 to 20.5 mm (mean distraction distance: 14 mm). Satisfactory cranial volume expansion and aesthetically pleasing morphological states were achieved in all cases. Regarding complications, one patient required re-operation because of dislocation of the device and skin erosion caused by infection around the penetrated wound. Finally, in a second patient a distortion of the device occurred, but no re-operation was needed.Conclusion The advantage of the distraction method is its applicability for Toddler or Elder Children Calvarial Reconstruction to correct cosmetic and functional problems. One disadvantage is the difficulty in using it for Infantile Calvarial Normalization because of thin calvarial bones and the necessity for re-operation to remove the device, which may result in it becoming a fixation procedure, essentially contraindicated for the fast-developing brain and calvarias. However, the efficacy of this procedure is that the many advantages outweigh the disadvantages as sufficient calvarial expansion and good results using the distraction method, especially in toddler and elder children age groups, can be achieved.     

Effect of chemotherapeutic agents on distraction osteogenesis. An experimental investigation in rabbits

Limb-salvage operations such as vascularised or non-vascularised osseous grafts and allograft and callus distraction methods have replaced amputations because of the increase in the life expectancy of patients with malignant tumours. In this study we aimed to evaluate the effects of chemotherapeutic agents on distraction osteogenesis. For this purpose, 23 rabbits randomly divided into two groups were included in the study. The experimental group and the control group consisted of 12 rabbits and 11 rabbits, respectively. The experimental group were administered chemotherapeutic agents with the protocol identified in the osteogenic sarcoma regimen. All the subjects were corticotomised in the metaphyseal-diaphyseal region, and both groups underwent distraction with a circular ring fixator. X-ray films, bone scintigraphy and histopathological examination were performed three times during the study. No difference between the two groups was observed in radiological, scintigraphical and histopathological studies carried out before the distraction period and following the end of the distraction period. In this study, it was shown that the use of antineoplastic drugs has no significant negative effect on distraction osteogenesis applied for reconstruction in rabbits. We think that it can be an alternative treatment method in humans as well. Received: 20 February 2000