钛重建板固定移植髂骨修复下颌骨缺损

目的评价游离髂骨移植钛重建板固定Ⅰ期修复下颌骨缺损的方法。方法对24例下颌骨良性病变及相近组织恶性病变侵犯下颌骨患者,扩大切除病变部位后,采用自体髂骨移植钛重建板固定即刻修复缺损下颌骨。结果术后3、6、12月随访,24例均获成功,3例病人存在轻度开口受限。结论钛重建板固定移植髂骨修复下颌骨缺损,能较好的恢复其形态和功能,是一种比较好的修复方法。     

下颌骨缺损腓骨瓣修复不同固定方式的有限元分析

背景:肿瘤、外伤等原因常常造成下颌骨节段性缺损,血管化腓骨瓣同期重建下颌骨缺损是目前最主要的修复方式。目前在临床上既有用重建钛板进行固定,又有用小型钛板固定,有临床回顾性研究表明重建钛板和小型钛板固定方式患者术后并发症率无明显差异,但目前仍缺少固定稳定性相关的生物力学研究。目的:试验用三维有限元法分析下颌骨节段性缺损腓骨瓣修复时用重建钛板和小型钛板固定后的应力分布和稳定性。方法:选择1例牙列完整的成年男性进行CT扫描,并将数据录入计算机之后重建下颌骨及牙列模型,根据下颌骨缺损的Jewer分类,建立H(一侧下颌体、下颌角、下颌升支和髁突的缺失),L(一侧下颌体缺失)和C(双侧下颌骨颏部缺失)3类缺损三维模型,利用三维有限元分析法,对这3种下颌骨缺损腓骨修复后重建板和小型板固定的力学分布特点和稳定性进行对比研究。结果与结论:①从应力云图可以大致判断,正常下颌骨应力较大值主要发生在髁突、髁颈、下颌角、磨牙、钛板钛钉等周围区域处,尤其以下颌角附近处应力最大;②H类缺损在重建钛板修复下颌骨时将对下颌角附近产生较大应力,局部应力集中达185MPa,在H类小型钛板、L类小型钛板及重建钛板修复条件下,钛板的应力为117-135 MPa,腓骨块的应力最大值基本在30.4 MPa以下,钛钉应力最大值为56.2 MPa;③H及L类缺损小型钛板、重建钛板修复后骨断端相对位移变化为15-18μm,C类缺损下颌骨钛板修复后骨断端基本不产生相对位移;④结果证实,重建钛板和小型钛板均能满足这3种缺损腓骨修复的生物力学要求。     

下颌骨缺损自体骨移植重建的生物力学研究

模拟临床下颌骨缺损状态和咬合力学环境,对自体骨移植重建下颌骨的生物力学效果进行分析、评价。根据人体骨骼和肌肉系统的解剖学特征,模拟B、BS＇＇S”和RB＇＇S”类缺损状态,建立腓骨和髂骨修复下颌骨三维有限元模型,对咬合力作用下重建下颌骨的应力状态进行了分析。结果表明,不同缺损腓骨重建,从右侧后牙牙槽嵴对应接骨处到左侧颏部对应接骨处,应力状态均从压应力到拉应力过渡．应力值大小受缺损方式影响;相同缺损腓骨与髂骨重建,以皮质骨为主要成分的腓骨重建下颌骨,应力分布较完整下颌骨有显著变化,移植骨上最大应力约为正常骨上5倍,呈现明显的应力遮挡;以松质骨为主要成分的髂骨重建下颌骨,应力状态和完整下颌骨基本相同。因此,髂骨重建下颌骨的力学性能较腓骨类更接近完整下颌骨．更利于术后愈合和进一步的功能重建。     

腓骨重建及小钛板固定下颌骨体部缺损的三维有限元分析

背景：临床研究中进行腓骨重建修复下颌骨缺损的力学研究是不现实的,而有限元分析法为下颌骨缺损修复重建的生物力学研究提供了新的方法。目的：建立腓骨重建小钛板固定下颌骨体部缺损的三维有限元模型,对其进行生物力学分析。方法：建立下颌骨体部缺损腓骨重建三维模型及内固定模型,在前牙、健侧第一磨牙、健侧第二磨牙加载    100 N咬合力,观察下颌骨模型重建前后的最大应力值和最大位移值情况,前牙加载和后牙加载下重建模型钛板、钛钉孔周围骨质的应力情况,前牙加载和后牙加载下腓骨前后端的最大位移值情况。结果与结论：正常下颌骨的最大应力集中在髁突颈部。在重建模型中,最大应力集中在健侧髁突颈部,加载相同咬合力的情况下重建下颌骨的最大应力值均大于正常下颌骨的最大应力值,前牙加载最大应力值大于后牙加载。在每块钛板内侧的两钉孔之间应力值最大,下颌角部位的应力比较集中,加载侧近下颌骨缺损处前上方的第一颗钛钉为下颌骨残端钛钉的最大应力集中部位,近腓骨中段后下方钛钉为腓骨端钛钉的最大应力集中部位。下颌骨残端近缺损处以及腓骨中段上板处的钉孔周围皮质骨为最大应力集中部位,前牙加载时的最大应力大于后牙加载时的最大应力。腓骨在X轴上从上缘到下缘的位移值不断减少,在Y轴上从前下方及后端至中份的位移值逐渐减少,在Z轴上从前端到后端的位移值逐渐减少。腓骨前端的最大位移值在Z轴方向,后端的最大位移值在Y轴方向上,前牙加载时的最大位移值均较后牙加载时的最大位移值大。说明下颌角后上方钛板最易折断,应对其进行加固处理;钛钉尖端和颈部应力比较大,应选择双皮质钛钉;腓骨端和下颌骨残端钛钉和钛板的应力比较大,应重视其稳定性和固位性;前牙咬合时的应力大于后牙咬合时的应力,修复后应避免前牙咬合。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

构建预制个性化骨瓣修复下颌骨缺损的灵长类动物模型

背景：预制个性化骨瓣具有创伤小、血运好、可带软组织、形状可定制等优点,可用来修复血管床欠佳的骨缺损。 目的：建立预制骨瓣修复灵长类下颌骨缺损的动物模型。 方法：对9只恒河猴进行头颅扫描并制作个性化钛网。将复合或者未复合人重组骨形态发生蛋白2的脱钙冻干骨、珊瑚装入个性化钛网,植入背阔肌中进行个性化、血管化组织工程骨瓣的预制或者原位植入下颌骨节段性缺损。13周时,个性化、血管化组织工程骨瓣预制成功,将其转移修复下颌骨节段型缺损。采用临床和组织学方法观察异位预制个性化骨瓣及原位植入人重组骨形态发生蛋白2修复下颌骨缺损的效果。 结果与结论：预制骨瓣和原位植入的复合人重组骨形态发生蛋白2的珊瑚能修复下颌骨节段性缺损;原位植入复合或未复合人重组骨形态发生蛋白2的脱钙冻干骨和单纯珊瑚不能修复下颌骨缺损。复合人重组骨形态发生蛋白2的脱钙冻干骨、珊瑚预制个性化、血管化组织工程骨瓣成功,转移后均能成功修复下颌骨缺损,而且修复下颌骨缺损的效果优于材料直接植入下颌骨缺损组。实验证实预制个性化骨瓣修复恒河猴下颌骨缺损模型是可行的。 中国组织工程研究杂志出版内容重点：肾移植;肝移植;移植;心脏移植;组织移植;皮肤移植;皮瓣移植;血管移植;器官移植;组织工程全文链接：     

非血管化髂骨移植同期修复下颌骨缺损的临床应用

目的：总结非血管化髂骨移植修复下颌骨肿瘤切除术后骨缺损的经验以及提高移植骨的成活率。方法：对52例下颌骨良恶性肿瘤患者切除肿瘤后采用自体非血管化髂骨同期移植修复下颌骨缺损。结果：术后3～6月随访，51例下颌骨缺损获得修复，外形及健侧咬合功能满意，其移植成活率为98．1％；1例感染失败(1．9％)。结论：采用自体非血管化髂骨同期植入修复下颌骨缺损是重建其功能和外形的较理想方法。     

三维重建技术与生物陶瓷相结合在下颌骨连续性缺损个体化修复中的应用

目的探讨三维重建技术与生物陶瓷相结合,制作下颌骨连续性缺损的个体化修复假体的可能性.方法 (1)应用三维重建技术获得下颌骨连续性缺损的三维重建模型;(2)完成下颌骨连续性缺损的个体化修复假体的生物陶瓷置换.结果应用三维重建技术,能够准确地获得与下颌骨连续性缺损相匹配的个体化生物陶瓷修复体.结论三维重建技术与生物陶瓷相结合可以完成下颌骨连续性缺损的个体化修复,这种技术可以满足下颌骨连续性缺损的外形和功能重建的需要.     

下颌骨节段性缺损修复组织工程中珊瑚支架残留率的研究

目的探讨骨髓基质干细胞(bone marrow stromal cell,BMSC)复合珊瑚修复犬下颌骨节段性缺损支架的残留率。方法体外扩增、成骨诱导培养犬BMSC,分别将第二代细胞复合珊瑚后植入犬自体右侧3cm的下颌骨节段性缺损,术后12周(n=6),32周(n=6)取材后分别通过Micro-CT检测和大体、组织学图像分析骨修复、支架残留率和生物力学修复强度。结果 Micro-CT检测和组织学图像分析均表明,BMSC-珊瑚组组织工程骨12周时支架残留率显著高于32周(P0.05),而新骨随材料降解逐步成熟;生物力学显示术后32周力学强度显著高于12周(P0.05)。结论自体成骨诱导BMSC复合珊瑚形成的组织工程骨可良好修复犬下颌骨节段性缺损,随时间延长材料逐步降解,组织工程下颌骨进一步成熟。     

数字化下颌骨的计算机重建

背景：随着计算机技术与医学相结合及医学与工科相结合的发展,越来越多的方法被用于下颌骨的重建。 目的：分析计算机三维重建技术在下颌骨缺损中的应用及意义。 方法：应用计算机检索万方数据库、维普数据库和PubMed数据库中1999-01/2011-10关于下颌骨数字化三维重建的文章,在标题和摘要中以“下颌骨;数字化;三维重建;计算机技术”或“CAD/CAM;mandible;3D mandible model”为检索词进行检索。 结果与结论：下颌骨缺损类型众多,不同个体间下颌骨形态差异也较大,简单应用下颌骨正常均值来代替个体下颌骨进行修复是不合适的,因而在进行下颌骨修复重建之前行个体化设计至关重要。随着数字化技术医学领域广泛应用,计算机辅助设计和计算机辅助制造较好的解决了此类问题,在计算机上设计出理想下颌骨形态以及它与上颌骨的解剖关系,通过快速原型技术复制出实体模型,便于体外精确测量分析并进行手术设计,而骨组织工程方法可以在计算机辅助下构建出一个与缺损区形态一致的三维、个体化骨组织,使得下颌骨在形态及功能的精确修复成为可能。 关键词：下颌骨;数字化;三维重建;计算机技术;数字化医学 doi:10.3969/j.issn.1673-8225.2012.09.037     

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。     

钛网打压植骨重建四肢长骨节段骨缺损☆

背景：四肢长骨节段骨缺损临床上常见,一直以来是骨科修复领域的难题。 目的：介绍钛网打压植骨重建四肢长骨节段骨缺损新方法的实验研究和临床用用。 方法：第一作者应用计算机检索1990至2011年 PubMed数据库(http://www.ncbi.nlm.nih.gov/PubMed), CNKI 数据库(www.cnki.net/index.htm), 和维普数据库(http//www.cqvip.com)有关钛网打压植骨重建四肢长骨节段骨缺方面的文献,英文检索词为“segmental bone defect,titanium mesh or titanium cage”;中文检索词为“四肢或长骨,骨缺损,钛网”。排除重复性研究、非四肢长骨和Meta分析类文献。根据纳入标准,共检索到30篇文献进行归纳总结。 结果与结论：钛网打压植骨重建四肢长骨节段骨缺损无论在大动物或是小动物的实验中均取得较好的成骨效果,优于非钛网的游离植骨和大块皮质骨游离植骨;自体骨、异体骨和人工骨均是可行的填充植骨材料,以自体松质骨为主的植骨材料的成骨效果相对较好,具有生物活性钛网较普通钛网的成骨效果更好。临床上,在四肢长骨各个部位的节段骨缺损中均取得很好的治疗效果,包括骨缺损长达十余厘米的病例。钛网打压植骨重建四肢长骨节段骨缺损新方法,改变了以往认为大于 6 cm以上长段骨缺损只适宜带血运的骨移植、而不适宜无血运游离植骨的传统观点。该方法较简单、安全、有效,是一种较理想的替代治疗长骨骨干部节段骨缺损的无血运游离植骨法。     

钛板重建下颌骨体部缺损的生物力学变化

BACKGROUND:Three-dimensional finite element has been widely used in the oral cavity field, but little is reported on the three-dimensional finite element reconstruction of the mandibular body using titanium plate. OBJECTIVE:To study the biomechanical characteristics of reconstructing the mandibular body using titanium plate. METHODS:We established a three-dimensional finite element model of mandibular body defect undergoing reconstruction using bicortical titanium screws and titanium plate. Under the simulated normal occlusion state, a 200 N vertical load was added to the central fossa of the occlusal surface of the right mandible first molar. Then, stress distribution and maximum displacement of the mandible, titanium screw, and titanium plate were analyzed. RESULTS AND CONCLUSION:Under the simulated normal occlusion state, mandible stress was concentrated in the mandibular body and mandibular branch, especially in the anterior and posterior edges of the mandibular branch and the lower edge of the mandible. The stress in the posterior edge of the mandible was lower than that in the anterior edge of the mandible, and moreover, the contact site between the titanium plate and the mandible also presented a concentration of stress. The maximum stress of the bicortical titanium screws appeared near the screw cap, and the stress was also concentrated at the contact site between the titanium screw and the titanium plate. The maximum stress of the titanium screw at the ascending branch of the mandible was higher than that of the titanium screw at the anterior end of the defect. For the titanium plate, the stress was mainly concentrated at the fixed site of the titanium screws; the peak stress of the anterior and posterior edges of the titanium plate was found at the contact site between the anterior end of mandibular defect and the titanium stress as well as between the ascending branch of the mandible and the titanium screw. After mandibular body reconstruction using the titanium plate, a displacement was likely to occur at the contact site between the anterior end of mandibular defect and the titanium plate. In conclusion, these findings indicate that mandibular body reconstruction using bicortical titanium screws and titanium plate is relatively stable, but the titanium plate fixed at the anterior part of the mandibular angle is prone to breakage.     

同种异体骨复合自体红骨髓移植治疗关节周围骨折

背景：关节周围骨折复位后常出现骨缺损,需进行植骨填充骨缺损以早期支撑关节面以防止关节面塌陷及移位。同种异体骨是治疗骨缺损的移植材料,但成骨能力差。自体红骨髓有成骨能力,但同种异体骨复合自体红骨髓移植治疗关节周围骨折的临床效果有待评定。 目的：采用锁定板固定、同种异体骨复合自体红骨髓移植治疗关节周围骨折的临床效果。 方法：纳入河北医科大学第三医院骨伤科治疗关节周围骨折患者43例。采用切开解剖复位关节面、将红骨髓与同种异体骨颗粒复合体植于骨缺损处,植骨完成后常规解剖锁定板内固定。胫骨平台骨折采用内侧、外侧或双侧锁定板固定。桡骨远端骨折采用背侧或掌侧锁定板固定,胫骨远端骨折采用胫骨远端内侧或外侧板锁定内固定。 结果与结论：患者43例共随访12个月至6年,平均4.3年。X射线片及CT复查结果显示,43例患者达骨性愈合,塌陷骨折复位良好。其中新鲜骨折愈合时间2-6个月,平均4个月;陈旧骨折愈合时间3-7个月,平均5.5个月。植骨后43例患者无明显免疫排斥反应,2例患者切口渗液较多,经换药2周愈合。切口感染患者1例,经引流换药4周伤口愈合,随访4年1个月至今感染未复发。根据Mankin和Komender标准评定,同种骨移植满意患者40例,占93%;不满意患者3例,占7%。结果证实,在锁定板支撑固定下,异体松质骨与自体红骨髓复合体移植治疗周围关节骨折可以起到近期支撑作用,防止关节面塌陷及骨折移位,并为关节周围骨折骨缺损提供骨重建材料,远期可以达到骨折愈合的目的。     

自体块状皮质骨修复种植区颌骨缺损

文题释义：自体块状皮质骨：自体块状皮质骨具有刚性的板层状结构,毛细血管的含量较低,因此移植后很难维持具有活性的成骨细胞或骨祖细胞,致密的矿化基质导致血管重建和长入的速度相对缓慢,但其空间维持能力强,生物相容性好,其中含有的成骨细胞和生长因子对骨再生起促进作用,是骨移植材料的“金标准”。 Onlay植骨：于两侧下颌外斜线处取长方形皮质骨块,在上颌左侧骨缺损区植入皮质骨块,右侧骨缺损区植骨同期植入种植体。 背景：自体骨有骨传导、骨诱导及骨生成的特性,同时具有良好的生物相容性,移植后无排斥反应。但关于自体骨块移植后的骨块是完全被吸收替代？还是能保留细胞活性长期存留？仍存在争议。 目的：观察皮质骨移植后改建再生过程中的组织学变化。 方法：6只健康比格犬麻醉后拔除两侧上颌前磨牙,并去除颊侧宽约10 mm、长约15 mm、厚度约2 mm的骨板,建立上颌骨缺损模型,在双侧下颌骨体颊侧切取相应大小的块状皮质骨并修整边缘。在上颌骨缺损区移植皮质骨块,一侧为单纯块状皮质骨移植,另一侧在块状皮质骨移植同期植入种植体。分别于骨移植后3,6个月取材,进行大体观测和组织学观察,分析移植骨块的吸收率、移植骨中的细胞存活率。实验方案经大连医科大学动物实验伦理委员会批准。 结果与结论：①大体观察可见移植骨块体积逐渐缩小,边缘圆钝,与基骨结合稳固;②6个月时全部种植体脱落;硬组织磨片可见移植骨块与基骨间存在新生骨连接;6个月时移植骨骨陷窝孔隙率明显低于3个月,移植骨吸收率显著高于3个月(均P < 0.05);③结果说明,块状皮质骨移植后,能够与受植区基骨发生骨结合,其内部的骨细胞部分保持活力,随着愈合期延长,新生骨细胞的比例增加,移植骨块的体积逐渐变小。皮质骨移植同期种植后移植物吸收明显,种植体骨结合不良。 ORCID: 0000-0001-5201-9377(王宁) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

富血小板纤维蛋白骨诱导动物模型的建立

BACKGROUND: At present, many studies have focused on platelet-rich fibrin combined with other bone substitute materials in repair of peri-implant bone defects and sinus lifting, but there is still a lack of research  about the platelet-rich fibrin alone in repair of critical-size bone defects. OBJECTIVE: To compare the effect of three kinds of bone substitutes, platelet-rich fibrin, Bio-Oss bone substitute and autogenous cancellous bone, in repair of bone defects. METHODS: Four areas of cylindrical critical bone defects with a diameter of 6.0 mm and depth of 10.0 mm were prepared in the medial femoral condyle of beagle dogs. Three areas of bone defects were implanted with autologous platelet-rich fibrin, Bio-Oss bone substitutes and autologous cancellous bone, respectively. The remaining one area of bone defect was not implanted any substance, as control group. X-ray and Micro-CT detections in bone defect area were conducted after 12 weeks of surgery. RESULTS AND CONCLUSION: (1) X-ray: the density of platelet-rich fibrin group was more higher, but still slightly lower than that of the surrounding normal bone tissue; the density of the Bio-Oss bone substitute group was more lower, but still higher than that of the surrounding bone tissues; the density of autologous cancellous bone group was more higher, which was close to that of the surrounding bone tissues; circular low-density images were visible in the control group. (2) Micro-CT: platelet-rich fibrin group was similar with the autogenous cancellous bone group, and their density was slightly lower than that of the surrounding normal bone tissues; the trabecular bone exlibited a clear regular arrangement, and no obvious interface; the Bio-Oss bone substitute group showed a high density image with clear interface; the bone defect area was still clearly visible in the control group, with a low-density image. The bone volume fraction and trabecular number in the platelet-rich fibrin and autologous cancellous bone groups were both higher than those in the Bio-Oss bone substitute group (P < 0.05). These results demonstrate that platelet-rich fibrin and autogenous cancellous bone have a similar bone repair effect.      

Design and fabrication of custom mandible titanium tray based on rapid prototyping

During the past few years, the combination of medical imaging and rapid manufacturing technique has proven to be a very important development. On the other hand, the conventional method has some drawbacks. For example, it takes longer time to complete an operation and it also presents some difficulty in matching the repaired contours. With advanced software and hardware, an image of an undamaged bone similar to that of the patient can be made from computerised tomography (CT); and a physical object constructed by the mirror-processed image data can be quickly fabricated with a high degree of fitting with the patient's bone. This paper presents a methodology for the design and fabrication of an individual titanium tray for the repair of mandible defects. Methods for the tray modeling using CAD system are presented: A 3D model of the bony defect is generated after the acquisition of helical CT data. An individual tray is designed using freeform surfaces geometries and fabricated by rapid prototyping (RP) technology. The results of tray filling with bone-grafting materials are then presented. Result: the tray is inserted into the patient mandible segment. The symmetry and reconstruction quality contour of the repaired mandible was satisfactory. Thus, the patient is able to eat normally. The bone-grafting material harvested from the anterior ilium was low. The clinical experience showed that rapid prototyping and reverse engineering software are effective methods of fabricating custom trays for mandibular reconstruction after bone loss due to a tumor.     

The effect on bone regeneration of a liposomal vector to deliver BMP-2 gene to bone grafts in peri-implant bone defects

Successful bone-implant osseointegration in large peri-implant bone defects is often difficult, even through autologous bone grafting. Recently, cell-mediated regional gene therapy was introduced to deliver potent morphogens or growth factors in regenerative medicine. We applied liposomal vectors carrying bone morphogenetic protein (BMP)-2 cDNA directly into freshly created peri-implant bone defects on pig calvariae, with or without autologous bone graft. The BMP-2 gene was efficiently introduced into immigrating cells and trabecular cells lining the marginal bone surrounding the bony defect. After 1 week, abundant BMP-2 protein was detected throughout the peri-implant bone defect by immunohistochemistry. At 4 weeks, BMP-producing cells were still present in the defect and peri-implant area, which significantly enhanced new bone formation, compared with the control groups. Interestingly within a week of BMP-2 gene delivery with bone grafts, most osteoblastic cells lining the grafted bone chips also produced BMP-2. Particulated bone was immediately reorganized into newly formed trabecular bone. Grafted bone without BMP-2 gene delivery was still scattered and new bone matrix formation was not detected until 4 weeks after bone grafting. In conclusion, direct application of the BMP-2 gene using a liposomal vector enhanced bone regeneration in a bony defect and gene delivery combined with bone graft could induce a rapid osseointegration of the bone-implant interface at earlier stage.     

经椎弓根入路不同植骨材料内固定治疗胸椎结核

背景：对于脊柱结核病灶清除后的骨质缺损,可以选择自体髂骨、自体肋骨、钛网加同种异体骨等多种植骨材料。 目的：对比椎弓根入路不同植骨材料内固定治疗胸椎结核的效果。 方法：纳入40例胸椎结核患者,其中18例伴有截瘫,15例存在后凸畸形,经正规抗结核治疗2-4周行后路椎弓根系统内固定,一期经椎弓根入路病灶清除植骨融合内固定,根据植骨材料的不同分为自体髂骨组、自体肋骨组、钛网加同种异体骨组。治疗后随访24个月,观察病灶愈合、植骨融合、截瘫恢复、后凸畸形矫正及不良反应发生率。 结果与结论：自体髂骨组植骨融合时间短于自体肋骨组、钛网加同种异体骨组(P < 0.05),后两组间植骨融合时间比较差异无显著性意义。3组均未发生植骨块及钛网脱落、断裂与移位,无骨不连及假关节等现象,无结核病灶复发。截瘫与脊柱后凸畸形患者经3-6个月的对症治疗,肌力基本恢复,脊柱后凸畸形基本矫正。表明自体髂骨治疗效果最好,自体肋骨、钛网加同种异体骨治疗效果相当。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

Fracture of titanium plates used for mandibular reconstruction following ablative tumor surgery

PURPOSE: The purpose of this study was to identify reasons for fracture of titanium mandibular reconstruction plates, when used to bridge lateral mandibular defects after ablative tumor surgery. MATERIALS AND METHODS: Sixteen titanium reconstruction plates from sheep mandibles were examined to identify reasons for the plate fractures. The broken plates and the seemingly unbroken plates were examined separately. The plates were removed from the mandibular bone and inspected by dye penetrant examination, metallography, optical microscope, scanning electron microscope, and energy dispersive X-ray spectrometer. Furthermore, axial load fatigue tests were performed in two different environments, air and physiologic salt solution, 0.9% NaCl, to compare titanium behavior in air and the human body. RESULTS: The site of crack initiation was the inner curvature of the reconstruction plate, and the cracks initiated as a result of stress concentration in the shoulder fillet of the plate. The cracks grew in a cyclic manner under masticatory loading of the mandible and the plate. The plate fracture occurred by means of fatigue. The corrosive environment did not affect the failure of the titanium plate, and the fracture was not caused by hydrogen embrittlement. The results revealed that the fatigue properties of the plates may have been impaired by the residual stresses generated in plate bending. CONCLUSIONS: Adjustive bending of the plates, in the surgical operation, may thus be an important cause of fracture of the reconstruction plates, because of generated residual stresses, which affect the mean stress in fatigue loading. To make the plates function without failure the plates should match closely with the three-dimensional shape of the mandible, to avoid any bending in the operative phase.