不同充填材料应用于山羊经皮椎体成形术的组织学研究

目的:研究聚甲基丙烯酸甲酯(PMMA)、磷酸钙人工骨(CPC)和复合重组人骨形态发生蛋白-2的磷酸钙人工骨(rhBMP-2/CPC)在山羊骨质疏松症模型上行经皮椎体成形术(PVP)后的组织学表现。方法:6～8岁雌性山羊8只,均行双侧卵巢切除术,术后4个月建立骨质疏松症模型。在C形臂X线机监视下,随机选取8只山羊的L2-L6的两节椎体行PVP,分别充填PMMA、CPC和rhBMP-2/CPC,保证每只山羊的两节穿刺椎体的充填材料各不相同,术后4个月处死所有动物,取出椎体,组织学观察。结果:8只山羊16个椎体的PVP均成功,共出现4个椎体的渗漏。肉眼观察:PMMA与松质骨界限清晰,一个椎体取材时交界面出现破碎和脱落现象;而CPC和rhBMP-2/CPC与椎体内松质骨界限不清,互相融合生长。HE染色光镜观察:PMMA与骨小梁松散结合,界限明显,未见PMMA吸收和新生骨形成;CPC均匀分布于骨小梁和骨髓组织内,有CPC吸收现象,同时可见有新生软骨样团块形成,并有新生骨组织形成向其中心长入;rhBMP-2/CPC除了CPC的表现外,可见成骨活动活跃。结论:在组织学上,rhBMP-2/CPC和CPC均具有降解活性和骨传导活性,优于PMMA。rhBMP-2/CPC还具有诱导成骨活性,可能成为PVP中强化骨质疏松性椎体的首选充填材料。     

Improved bone-screw interface with hydroxyapatite coating: an in vivo study of loaded pedicle screws in sheep

STUDY DESIGN: An in vivo sheep model with loaded pedicle screws was used, wherein each animal served as its own control. OBJECTIVES: To examine the effects of hydroxyapatite (HA) coating on the bone-to-implant interface in loaded spinal instrumentations. SUMMARY OF BACKGROUND DATA: Spinal instrumentation improves the healing rate in spinal fusion, but screw loosening constitutes a problem. HA coating of other implants has resulted in favorable effects on the bone-to-implant interface. METHODS: Nine sheep were operated on with destabilizing laminectomies at two levels: L2-L3 and L4-L5. Each level was stabilized separately with a four-screw instrumentation. Uncoated screws (stainless steel) or the same type of screws coated with plasma-sprayed HA were used in either the upper or the lower instrumentation in a randomized fashion. The animals were killed at 6 or 12 weeks after surgery. The specimens were embedded in resin, ground to approximately 10 microm, and stained with toluidine blue. Histomorphometric evaluation was carried out in a Leitz Aristoplan (Wetzlar, Germany) light microscope equipped with a Leitz Microvid unit. RESULTS: The average percentage of bone-to-implant contact after 6 weeks was 69 +/- 10 for the HA-coated screws and 18 +/- 11 for the uncoated screws (P < 0.03), and after 12 weeks 64 +/- 31 (HA-coated) and 9 +/- 13 (uncoated, P < 0.02). The average bone volume in the area close to the screw was significantly higher for the HA-coated screws at both 6 and 12 weeks. CONCLUSIONS: HA coating improved the bone-to-implant interface significantly, indicating that HA coating can become useful for improving the purchase of pedicle screws.     

椎体内注射医用生物蛋白胶对松质骨创面出血影响的实验研究

目的:探讨椎体内注射医用生物蛋白胶减少松质骨创面出血的有效性与安全性.方法:10只成年家犬全麻下前路暴露L2～15椎体,其中6只动物L2～L5椎体随机分为实验组与对照组,每组每只2个椎体.实验组椎体内注射医用生物蛋白胶,对照组未注射给药.给药30s后同时于L2～L5椎体前方作直径8mm、深6mm的骨缺损,记录骨创面的控制出血时间、止血时间、出血量及各组10min内止血百分比.另4只动物L2～L5椎体内注入医用生物蛋白胶与欧乃派克混合物.给药30min后行CT扫描计算椎体内药物扩散体积百分比,观察药物局部渗漏及静脉渗漏情况.所有动物实验前后检测血浆凝血酶原时间(PT),术后3d拍胸部X线片后处死,剖胸探查有无肺梗死灶.结果:实验组和对照组的控制出血时间分别为97±48s和417±101s(P<0.001),止血时间分别为291±167s和890±237s(P<0.001),出血量分别为0.80±0.67g和4.39±1.84g(P<0.001),10min 内止血百分比分别为91.67%和16.67%(P=0.001).药物扩散体积百分比为72.1%±11.2%.药物造影组CT扫捕未发现静脉渗漏,椎间孔渗漏1个(6.25%),椎管内渗漏5个(31.25%).所有动物实验前、后PT转异率无显著性差异(P=0.628).所有动物术后未发现神经损伤症状,胸片未见肺梗死征象,剖胸探查末发现肺梗死灶.结论:成年家犬椎体内注射医用生物蛋白胶可明显减少松质骨创面出血,安全性较好.     

The route of metastatic vertebral tumors extending to the adjacent vertebral body: a histological study

Background  

Each vertebra can be regarded as a compartment surrounded by several anatomically characterized barriers. However, in some cases tumors extend beyond these barriers. The route of vertical extension to the adjacent vertebrae is unclear. The extent of vertical extension of a metastatic spinal tumor is important in making the preoperative decision regarding the cranio-caudal surgical margin. The objective of this study was to investigate the route of vertical extension of metastatic vertebral tumors.     

Radiological and histological analysis of cortical allografts: an experimental study in sheep femora

Introduction We developed an experimental model in sheep femora to evaluate the process of cortical allograft incorporation.Materials and methods Twenty-four sheep were divided into four groups according to the various treatments of cortical allografts as follows: fresh, frozen, autoclaved, and frozen with perforation. Periodical radiographic and histological evaluations were performed for each group.Results Perforated frozen allograft proved to be superior radiographically in the first stage to fresh, frozen, and autoclaved forms. Revascularization was demonstrated by both Spalteholzs technique and histological examination. Histological analysis also showed creeping substitution, from the host bone to the allograft, which increased the reabsorption to facilitate new bone penetration, including endochondral ossification at the host-graft interface.Conclusion We believe that endochondral ossification is probably a biological event occurring routinely during the bone healing process and that the processes of incorporation of variously treated cortical allografts differ only at the early phase of implantation.     

Bladder augmentation with different forms of intestinal grafts: an experimental study in the pig

OBJECTIVE: To create an experimental animal model to examine changes in bladder volume and histology after bladder augmentation in growing individuals and from the model, evaluate a method using demucosalized intestinal grafts and short-term bladder drainage. MATERIALS AND METHODS: The study comprised 21 piglets: in group 1, seven underwent a sham operation; in group 2, seven piglets underwent bladder augmentation with full-thickness caecum after a major bladder resection; in group 3 seven underwent the same procedure but with demucosalized caecum. The bladder volume and area of the intestinal segment were measured peroperatively and when the animals were killed 2 months later. Bladder specimens were taken for histological examination. RESULTS: The mean preoperative bladder volumes were similar among the groups; in the control group, volumes increased from 58 to 165 mL and in group 2 from 63 to 255 mL, with an increase in area of the intestinal segment from 59 to 138 cm2. In group 3 the volume was unchanged, from 63 to 71 mL, with a decrease in area from 58 to 5 cm2. Control bladders showed normal urothelium with neutral mucins and sialomucins. In group 2, there was metaplasia in the border between urothelium and colonic epithelium, with enhancement of sialo- and sulphomucins. Demucosalization resulted in extensive fibrosis, with a monolayer of urothelial cells showing metaplasia. CONCLUSIONS: The experimental model was successful; the observed changes in bladder volume correlated well with the fate of the intestinal implant, because the bladder resection was major. This is essential, as the bladder remnant has some growth potential. Full-thickness grafts grew faster than the normal bladder. Mechanical demucosalization, including submucosa, results in shrinkage despite short-term drainage. Glandular metaplasia, with production of sialomucins and sulphomucins, occurs at the junction between bladder and colon, irrespective of mucosal removal.     

机械通气时不同黏稠度模拟痰液流变学的实验研究

目的探讨机械通气条件下,不同黏稠度模拟痰液的流动状态,以供临床参考。方法选择1只巴马小猪,将配制的相当于Ⅰ度、Ⅱ度、Ⅲ度黏度模拟痰液经气管镜导管注射至段支气管。将猪翻转180°后,观察模拟痰液向气管流动的速度,观察1min,然后向段支气管注入2mL生理盐水进行湿化,10s后将猪翻转180°,观察痰液向气管流动的速度,流至隆突时停止。结果Ⅲ度痰液黏附于支气管壁不流动;Ⅱ度痰液集中于段支气管开口,在表面张力作用下不流动;Ⅰ度痰液流动速度2mm/min。Ⅲ度痰液用生理盐水湿化后,痰液的流动速度为120mm/min,15s流至隆突。结论机械通气条件下,Ⅲ度和Ⅱ度痰液几乎不流动,Ⅰ度痰液流动缓慢,应注意加强气道湿化。气道内注射生理盐水湿化后,翻转180°体位后吸痰应在15s内进行,以避免痰液流向对侧肺导致感染播散。     

羟基磷灰石涂层钢板螺钉改善骨折稳定性的实验研究

目的　比较国产羟基磷灰石 (hydroxyapatite ,HA)涂层钢板螺钉与非涂层钢板螺钉在体负重情况下对骨折的内固定效果。方法　四孔钢板螺钉 2 4套 ,附加螺钉 60枚 ,对其中 12套钢板、30枚螺钉行HA等离子喷涂 ,其余的钢板、螺钉不喷。 12只成年杂种犬 ,每只犬的两侧肱骨线型骨折后分别以HA涂层钢板、螺钉或非涂层钢板、螺钉内固定 ,每只犬的右胫骨间隔 2cm交递置入HA涂层钉和非涂层钉共 5枚。按术后即刻、3、6周将犬分成 3组。处死后行组织学观察和生物力学测试。结果　组织学观察 :术后 3、6周组HA涂层均无明显降解 ,其与不锈钢基底结合良好 ,与骨组织结合紧密 ,3、6周组HA涂层钢板下都有不同程度的皮质骨上新生骨形成 ,该处未见明显的骨质疏松。相反非涂层钢板、螺钉与骨接触不紧密 ,其间有薄层纤维组织生长 ,钢板下可见不同程度的骨质疏松。力学测试 :3、6周组犬中HA涂层组的三点折弯强度及螺钉拔出强度均比非涂层组大。结论　国产HA涂层的钢板螺钉可增加骨折内固定的稳定性。     

Knee immobilization on meniscal healing after suture: an experimental study in sheep

Immobilization and nonweightbearing may influence the healing of sutured meniscal lesions in the avascular zone. In 12 sheep, 3 to 4 months of age, a 0.5-cm longitudinal lesion was made in the middle segment and posterior portion of the medial meniscus of the left knee in the avascular zone. The lesion was sutured immediately. The knees of six sheep were immobilized with a monolateral external fixator, which crossed the knee, and the knees in the other six sheep were not immobilized. The animals were sacrificed 6 weeks after the operation. Specimens from the anterior meniscus were used for histologic and vascular studies, and the posterior meniscus was used for mechanical testing. Repair was observed in two of 12 sheep in the form of fibrous tissue. Fibrochondrocytes and synovial cells were involved. Meniscal fibrochondrocytes from the nearest meniscal tissue, synovial cells from the femoral and tibial meniscal surfaces, and fibroblastic cells migrating through the suture channel provide cell access to the meniscus lesion. Sutured menisci, immobilized or not, support less than 50% of a normal load and are mechanically weak.     

bBMP复合纤维蛋白胶治疗绵羊脊柱骨质疏松的实验研究

目的探索能够在短期内有效提高骨质疏松椎体骨密度的局部治疗方法。方法采用卵巢切除法（OVX）对6只成年雌性绵羊去势,低钙饲养1年后建立骨质疏松模型。采用拉丁方设计方案,通过经椎弓根注射途径,分别在每只动物的L4、L5、L6注射3种药物：实验组A20mg bBMP/FS,对照组B20mg bBMP,对照组C单纯FS。术后3个月时采用双能X线吸收骨密度测量仪和Micro-CT进行测量分析。结果拉丁方分析BMD显示：实验组BMD（1.334g/cm^2）明显高于对照组BMD（1.139g/cm^2和1.163g/cm^2）。Micro-CT分析表明：实验组骨小梁的密度、连接率均显著高于对照组。结论bBMP复合纤维蛋白胶可以促进骨小梁的改建,改善骨小梁的三维结构,增加椎体的骨质密度,因此可以作为局部治疗脊柱骨质疏松的新型方法之一。