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21.
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
22.
目的观察去势手术对绵羊皮质骨和松质骨的骨密度、骨小梁结构及力学性能的影响。方法20只雌性成年绵羊(4±1.5)随机分为去势4个月组(OVX-4months)(4只)、去势12个月组(OVX-12months)(8只)和假手术(Sham)组(8只)。OVX组行双侧卵巢切除术,假手术组仅显露双侧卵巢,术中测定腰椎骨密度。分别与术后4、12个月处死动物,测定股骨颈、股骨干及股骨髁的骨密度,并行MicroCT分析及生物力学测试。结果去势12个月后(OVX-12months)组腰椎、股骨颈及股骨髁的骨密度较对照组显著降低,而皮质骨骨密度无明显降低。其松质骨的相对骨体积(BV/TV)、骨小梁厚度(Tb.Th)、骨小梁数目(Tb.N)较对照组显著降低,表面积体积比(BS/BV)、骨小梁间隙(Tb.Sp)则较对照显著增高。生物力学测试表明,去势12个月后,腰椎松质骨的最大压缩应力分别较Sham组和OVX-12months组下降82.5%和85.9%,力学强度显著下降,而皮质骨的力学强度无显著变化。结论去势12个月后,绵羊腰椎、股骨部的松质骨BMD及骨小梁空间结构参数明显降低,力学强度也显著下降,可以作为骨质疏松的大动物模型。而皮质骨的骨密度和力学强度下降不明显,需要更长的去势时间。 相似文献
23.
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
24.
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
25.
新型可膨胀椎弓根螺钉在骨质疏松性腰椎融合与固定手术中的初步应用 总被引:1,自引:0,他引:1
目的 评价新型可膨胀椎弓根螺钉(Thunder钉)在骨质疏松性腰椎椎体中固定的可靠性及其临床疗效.方法 随访2006年8月至2007年12月,应用Thunder钉治疗合并骨质疏松症的各种腰椎疾患42例(236枚螺钉),其中腰椎退行性疾病24例,腰椎结核二期后路融合手术8例,腰椎骨质疏松性压缩骨折6例,腰椎翻修手术4例.所有病例术前均行骨密度检查,患者腰椎骨密度平均下降2.6个标准差.术后处理与其他腰椎内固定术后患者相同.术后1周、3个月、半年、1年及2年随访患者,摄X线片并进行CT扫描三维重建,了解椎弓根螺钉稳定性及脊柱融合情况.结果42例患者均获平均16(12~24)个月的随访.术后3、6、12及24个月的影像学检查显示,所有Thunder钉位置良好,无螺钉松动、断裂迹象,评分平均值分别为3.0、3.0、2.9和2.9.脊柱骨融合于术后随时间延长趋于完善,骨融合评分平均值分别为2.3、2.5、3.0、3.0.所有患者临床症状缓解,疗效满意.结论 Thunder钉具有良好的钉-骨界面结合,能够提高螺钉在骨质疏松椎体中的固定强度,为脊柱融合提供良好的基础,临床疗效满意. 相似文献
26.
目的:优化人工颈椎复合关节系统(artificialcervical joint complexACJC)并进行生物力学评价.方法:在前期设计的基础上,以及通过测量工作得到的关于正常人体颈椎解剖和运动学参数,优化ACJC.新鲜的人体颈椎标本14具,随机取出7具作为正常颈椎组,在MTS858Mini Bionix II生物材料实验系统进行稳定性实验并测定各节段椎间活动度.随后将标本随机分为钢板固定组和假体植入组,每组7例,对每组标本分别进行实验前处理:钢板固定组依次行前路C5椎体次全切、植骨融合内固定术;假体植入组依次行C5椎体次全切、假体植入术.试验同正常颈椎组.结果:稳定性实验显示假体植入组与正常颈椎组相比,下颈椎在三维六自由度的ROM均无显著差异.而钢板固定组在前屈、后伸、左右侧弯中的活动范围(ROM)均小于显著其余两组.手术节段活动度测定显示,钢板固定组的各向ROM均显著小于其余两组,而假体植入组仅在后伸运动中ROM显著大于正常颈椎组,其余活动中均与正常颈椎组无显著差异.临近椎间活动度测定显示,三组间下位椎间隙活动度无显著差异;对于上位椎间隙,假体植入组与正常颈椎组无显著差异.钢板固定组前屈、后伸活动度... 相似文献
27.
教育国际化已经成为高等院校发展趋势,但是双语教学仍是制约教育国际化的重要因素。目前,如何在临床医学课程中开展双语教学并取得良好的教学效果,是医学双语教育中一个广泛关注的焦点。该文针对我校开展双语教学存在的问题进行反思,希望能够促进临床医学双语教学的顺利开展。 相似文献
28.
目的 评价新型丝攻结合骨水泥(PMMA)增强椎弓根螺钉稳定性的效果.方法 选取34个新鲜小牛腰椎,每个椎体的一侧椎弓根直接拧入螺钉(空白组);另一侧将PMMA(2.0mL)经新型丝攻注入钉道后拧入螺钉(实验组).24h后行轴向拔出实验和周期抗屈实验.结果 实验组中螺钉的最大轴向拔出力和能量吸收值均显著高于空白组(P<0.05);实验组中的螺钉能够耐受更大的负荷或者在同等负荷下产生较小的位移.结论 新型丝攻结合PMMA可以显著增加椎弓根螺钉固定的稳定性. 相似文献
29.
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
30.
人工颈椎复合关节系统优化设计的解剖学参数测量 总被引:2,自引:0,他引:2
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