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31.
Objective: To investigate the properties of screwbone interface of expansive pedicle screw (EPS) in osteoporotic sheep by micro-CT and histological observation.
Methods: Six female sheep with bilateral ovariectomyinduced osteoporosis were employed in this experiment. After EPS insertion in each femoral condyle, the sheep were randomly divided into two groups: 3 sheep were bred for 3 months (Group A), while the other 3 were bred for 6 months (Group B). After the animals being killed, the femoral condyles with EPS were obtained, which were three-dimensionally-imaged and reconstructed by micro-CT. Histological evalu-ation was made thereafter.
Results: The trabecular microstructure was denser at the screw-bone interface than in the distant parts in expan-sive section, especially within the spiral marking. In the non- expansive section, however, there was no significant differ-ence between the interface and the distant parts. The regions of interest (ROI) adjacent to EPS were reconstructed and analyzed by micro-CT with the same thresholds. The three-dimensional (3-D) parameters, including tissue min- eral density (TMD), bone volume fraction (BVF, BV/TV), bone surface/bone volume (BS/BV) ratio, trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp), were sig- nificantly better in expansive sections than non-expan-sive sections (P 〈 0.05). Histologically, newly-formed bony trabeculae crawled along the expansive fissures and into the center of EPS. The newly-formed bones, as well as the bones at the bone-screw interface, closely contacted with the EPS and constructed four compartments. Conclusions: The findings of the current study, based on micro-CT and histological evaluation, suggest that EPS can significantly provide stabilization in osteoporotic cancellous bones. 相似文献
Methods: Six female sheep with bilateral ovariectomyinduced osteoporosis were employed in this experiment. After EPS insertion in each femoral condyle, the sheep were randomly divided into two groups: 3 sheep were bred for 3 months (Group A), while the other 3 were bred for 6 months (Group B). After the animals being killed, the femoral condyles with EPS were obtained, which were three-dimensionally-imaged and reconstructed by micro-CT. Histological evalu-ation was made thereafter.
Results: The trabecular microstructure was denser at the screw-bone interface than in the distant parts in expan-sive section, especially within the spiral marking. In the non- expansive section, however, there was no significant differ-ence between the interface and the distant parts. The regions of interest (ROI) adjacent to EPS were reconstructed and analyzed by micro-CT with the same thresholds. The three-dimensional (3-D) parameters, including tissue min- eral density (TMD), bone volume fraction (BVF, BV/TV), bone surface/bone volume (BS/BV) ratio, trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp), were sig- nificantly better in expansive sections than non-expan-sive sections (P 〈 0.05). Histologically, newly-formed bony trabeculae crawled along the expansive fissures and into the center of EPS. The newly-formed bones, as well as the bones at the bone-screw interface, closely contacted with the EPS and constructed four compartments. Conclusions: The findings of the current study, based on micro-CT and histological evaluation, suggest that EPS can significantly provide stabilization in osteoporotic cancellous bones. 相似文献
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33.
目的评价一种新型可膨胀聚甲基丙烯酸甲酯(poly methyl methacrylate,PMMA)骨水泥的理化性质、生物力学特征及其生物相容性。方法以聚丙烯酸(ploy acrylic acid,PAA)改性PMMA研发一种新型具有膨胀特性的骨水泥(expandable bone cement,EBC)以改善PMMA骨水泥(PMMA bone cement,PBC)聚合体积收缩现象。通过测定EBC的膨胀倍率、聚合温度、面团时间、凝固时间评价EBC的理化性质;压缩实验测定EBC的压缩强度及弹性模量等生物力学的特征。用含有EBC及PBC浸提液的培养基培养成骨细胞,CCK-8测定EBC的细胞毒性作用,评价EBC的生物相容性。结果 EBC吸模拟体液24 h平衡后体积膨胀约8.80%。同时EBC的聚合温度为(51.73±3.64)℃,显著低于PBC,差异具有统计学意义(P0.05),且适宜注射的面团时间为(5.06±0.46)min,较PBC显著延长,差异具有统计学意义(P0.05),两者的凝固时间差异无统计学意义(P0.05)。EBC的压缩强度为(36.15±11.19)MPa,明显高于正常椎体松质骨;但弹性模量为(849.26±324.47)MPa,显著低于PBC(2 148.89±176.13)MPa,差异具有统计学意义(P0.05)。细胞毒性实验显示EBC与PBC相对吸光度分别为1.30±0.11、1.31±0.08,两者之间差异无统计学意义(P0.05)。可见与PBC相似,EBC具有较好的生物相容性。结论 EBC具有良好的膨胀性能,可有效克服PBC聚合体积收缩的缺陷。EBC聚合温度较低、面团时间较长,弹性模量较低可降低成形术后邻近椎体再骨折风险,且生物相容性较好,有望应用于椎体成形术及关节置换术。 相似文献
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目的总结全膝关节置换术后早期并发症的发生及其原因。方法通过2003年6月至2005年6月50例全膝置换完整病例进行回顾性研究,结合文献找出早期并发症发生的原因。结果术后早期并发症共15例,其中包括:手术切口愈合不良4例,泌尿或呼吸系统感染5例,电解质紊乱3例,术后心功能衰竭1例,呼吸衰竭1例,腓总神经损伤1例。总体并发症发病率30%。结论全膝关节置换术后并发症的发生与手术操作、患者个体差异、围手术期处理等因素有关。只有术前准备充分,术中操作仔细、规范,术后针对不同情况采取积极预防措施是避免术后早期并发症发生的关键。 相似文献
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目的 测试并比较自行设计的膨胀式椎弓根螺钉 (expansivepediclescrew ,EPS)与USS ,Tenor ,CDH椎弓根螺钉的最大轴向拔出力 ,评价EPS螺钉的椎弓根固定作用。方法 将 6 0个新鲜小牛腰椎随机分成 3组 ,每组 2 0个椎体(4 0侧椎弓根 ) ,每组均随机在一侧拧入EPS螺钉 ,对侧则分别拧入USS ,Tenor ,CDH螺钉 ,进行螺钉拔出实验 ,测试并记录最大轴向拔出力。结果 EPS ,USS ,Tenor ,CDH螺钉的最大轴向拔出力分别为 2 6 5 8 4N± 816 7N ,192 9 9N±4 84 9N ,184 9 8N± 5 75 9N ,1980 9N± 836 4N。EPS螺钉和其它三种螺钉的最大轴向拔出力相比均有非常显著差异 (P <0 0 1)。结论 EPS螺钉较目前使用的USS ,Tenor ,CDH非膨胀椎弓根螺钉有更好的固定作用。 相似文献
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目的:探讨复合牛骨形态发生蛋白(bBMP)的纤维蛋白胶(FS)强化去势绵羊椎弓根螺钉固定作用的生物力学效果.方法:选取4只去势绵羊腰椎2~6双侧共36个椎弓根随机分为3组:FS/bBMP组,磷酸钙骨水泥(CPC)组,空白对照组,每组12个椎弓根.FS/bBMP组钉道内注入复合bBMP的FS,CPC组注入CPC,空白对照组钉道内不作任何处理.拧入螺钉饲养3 mo后取材.在材料试验机上进行轴向拔出试验和周期抗屈试验.结果:FS/bBMP组的最大拔出力为(909.98±155.65)N,CPC组为(994.20±122.78)N,两组差异无统计学意义(P>0.05).两组均明显高于空白对照组的(524.65±118.35)N,差异具有统计学意义(P<0.05).周期抗屈试验800个周期内,FS/bBMP组螺钉位移为(1.478±0.466)mm,CPC组为(1.274±0.393)mm ,空白对照组为(1.978±0.531)mm,其中FS/bBMP组与CPC组两组差异无统计学意义(P>0.05),两组均小于空白对照组,差异有统计学意义(P<0.05).结论:在骨质疏松椎体内植入椎弓根螺钉时,添加复合bBMP的FS可显著提高螺钉稳定性. 相似文献
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目的:了解目前中国残存缠足畸形的形态改变特点.方法:调查山东、云南、福建、陕西4省共241名有缠足史妇女,年龄69-100(80±6)岁.对所有调查对象拍摄正位、侧位、斜位、足底照片,并测量双足长度和宽度,分析总结缠足畸形的形态特点.结果:畸形足可分为两种类型:跟行足型和马蹄足型.山东、云南、陕西的缠足畸形为跟行足畸形,形态特点为后跟大,前足小,足弓高,第2-5趾在脚下,缠足妇女以跟行足步态行走;福建地区缠足畸形类似马蹄足畸形,形态特点为后跟小,前足大,足弓高,前足平面低于足跟平面,呈阶梯状,缠足妇女以马蹄足步态行走.两型缠足畸形足部长度和宽度与正常妇女相比明显偏小.结论:目前中国残存缠足畸形按照畸形足形态分为跟行足型和马蹄足型两种类型,不同的缠足方法导致不同的畸形形态特点.有缠足史的妇女双足长度和宽度明显小于正常妇女. 相似文献
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目的通过离体实验评价两阶段注射法在椎体成型术中对骨水泥渗漏的预防作用。方法50个新鲜绵羊腰椎随机分成实验组及对照组。分别采用两阶段注射法及常规椎体成型方法,在X线透视引导下向椎体内注射总量为3mL的PMMA,模拟临床椎体成型术。实验组首先向椎体后部注射0.5mL的PMMA,待其固化后,再次向椎体内注射2.5mL的PMMA。对照组以常规方法向椎体内注射3mL的PMMA。通过X线及肉眼直视,统计两组骨水泥渗漏的发生率。结果对照组有8例出现骨水泥向椎管内渗漏,而实验组中仅2例,显著低于对照组(P=0.032)。尽管实验组骨水泥总体渗漏发生率56%高于对照组44%,但无统计学差别。结论两阶段注射法可显著降低骨水泥向椎管内方向渗漏的发生率。 相似文献
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目的运用微量注射泵向椎体内灌注盐酸及椎体整体浸泡的脱钙方法,快速建立绵羊腰椎骨质疏松性生物力学模型。方法(1)设计一款可拧入椎弓根带侧孔的圆柱形灌注连接器,做为椎体内部与注射泵的桥接装置。(2)将(3±0.5)岁新鲜绵羊腰椎48个,随机分为4个处理组:A组(0 h脱钙,即空白组),B组(2 h脱钙),C组(4 h脱钙),D组(6 h脱钙)。每组12个椎体。(3)检测各组椎体脱钙前后BMD;进行生物力学实验:测试最大轴向拔出力(Fmax)和最大抗压强度及其能量吸收值。同时各组取少量骨质制成组织切片,对脱钙后绵羊腰椎骨小梁微观结构进行观察。结果B、C、D处理组的BMD均值、最大轴向拔出力均值和最大抗压强度及其能量吸收值均值都低于A组(P0.01),且随脱钙时间的延长依次降低(P0.01)。椎体的最大轴向拔出力及最大抗压强度与BMD存在正相关关系,亦与BMD的下降值存在负相关。切片显示:B、C、D组椎弓根处骨小梁较A组骨小梁厚度明显变薄、数量减少,间距增宽,部分骨小梁连续性中断,骨髓腔扩大。结论运用微量注射泵向椎体内灌注盐酸及整体浸泡的脱钙方法,可快速、有效、可控的建立近似于骨质疏松状态下的生物力学模型,为在真正骨质疏松状态下的生物力学研究提供参考依据。 相似文献
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目的:为研制人工颈椎复合关节系统提供中下颈椎体、椎间盘解剖学数据.方法:志愿者76人,其中男性32人(21~44岁,平均年龄29.31岁),女性44人(19~45岁,平均年龄32.20岁),测量各椎体与椎间隙前缘、中份及后缘的高度,数据进行统计和分析.结果:椎体前缘、中份、后缘高度(mm),男性分别为:17.58~19.97,15.68~17.69,18.17~19.77;女性分别为:15.13~17.80,13.34~15.05,15.57~17.06.椎间隙前缘、中份、后缘高度(mm):男性分别为5.81~7.23,7.59~9.19,4.65~5.54;女性分别为;4.88~5.37,6.82~7.89,4.03~4.47.各测量结果在性别间有统计学意义(P<0.05).结论:由此得到了中下颈椎体及椎间盘的解剖学参数,这可以为人工颈椎复合关节系统假体设计、制造和临床运用提供参考依据. 相似文献