松质骨螺钉骨水泥强化的生物力学和组织学研究

目的通过动物实验观察不同骨水泥强化松质骨螺钉的生物力学和组织学变化动态,为骨质疏松骨折患者内固定提供理论基础。方法在10只杂种犬胫骨近端制作松质骨螺钉植入的动物模型,分别采用碳酸化羟基磷灰石水泥(CHC)和聚甲基丙烯酸甲酯(PMMA)强化,分别于术后5d、4、8、12和16周处死动物,观察螺钉拔出的生物力学和组织学变化。结果CHC强化的螺钉拔出力随手术后时间的延长而逐渐升高,16周时达到(512.5 14.5)N,而PMMA强化组螺钉拔出力则随手术后时间的延长而逐渐降低。CHC-骨界面结合紧密,并且随时间延长出现CHC降解和骨长入,而PMMA-骨界面形成一层纤维组织。结论CHC强化能够提高松质骨螺钉植入体内的稳定性,并且随植入时间延长而逐渐升高。     

经皮椎体成形术中骨水泥填充对患者凝血功能的影响

目的:探讨经皮椎体成形术中骨水泥对骨质疏松性椎体压缩骨折患者凝血功能的影响及临床意义.方法:2006年12月至2007年12月,对24例骨质疏松性椎体压缩骨折患者行经皮椎体成形术,男6例,女18例:年龄48～83岁,平均69岁.脊柱骨折部位为T5-L3,共44个椎体,其中胸椎20个椎体,腰椎24个椎体.采用C型臂X线机透视引导下行经皮椎体成形术,注射聚甲基丙烯酸甲酯骨水泥(PMMA).分别在注入骨水泥前10min、注入骨水泥后10min、30min、1h、2h及3h时检测患者凝血功能相关指标,包括血浆凝血酶原时间(PT)、活化的部分凝血活酶时间(APTT)、凝血酶时间(TT)、纤维蛋白原(FIB)、鱼精蛋白副凝固试验(3P试验)及血浆D-二聚体(D-D)含量,并进行统计学分析.结果:经皮椎体成形术中注人骨水泥10min后PT缩短、FIB增高、3P试验阳性率升高,D-D含量增高,1h时达到高峰后开始下降.注入骨水泥后10min、30min、1h、2h四个时间点与注入骨水泥前相比较均有显著性差异(P<0.05).活化的部分凝血活酶时间(APTT)、凝血酶时间(TT)在各时间点与注入骨水泥前比较均无显著性差异(P>0.05).3h后骨水泥对这些指标的影响基本消除,各项指标与注入骨水泥前比较均无显著性差异(P>0.05).结论:经皮椎体成形术中骨水泥填充会引起患者一过性血液高凝状态,在注入骨水泥后的3h内需严密监测病情,以防血栓性疾病发生.     

A mechanical microconnector system for restoration of tissue continuity and long-term drug application into the injured spinal cord

Complete transection of the spinal cord leaves a gap of several mm which fills with fibrous scar tissue. Several approaches in rodent models have used tubes, foams, matrices or tissue implants to bridge this gap. Here, we describe a mechanical microconnector system (mMS) to re-adjust the retracted spinal cord stumps. The mMS is a multi-channel system of polymethylmethacrylate (PMMA), designed to fit into the spinal cord tissue gap after transection, with an outlet tubing system to apply negative pressure to the mMS thus sucking the spinal cord stumps into the honeycomb-structured holes. The stumps adhere to the microstructure of the mMS walls and remain in the mMS after removal of the vacuum. We show that the mMS preserves tissue integrity and allows axonal regrowth at 2, 5 and 19 weeks post lesion with no adverse tissue effects like in-bleeding or cyst formation. Preliminary assessment of locomotor function in the open field suggested beneficial effects of the mMS. Additional inner micro-channels enable local substance delivery into the lesion center via an attached osmotic minipump. We suggest that the mMS is a suitable device to adapt and stabilize the injured spinal cord after surgical resection of scar tissue (e.g., for chronic patients) or traumatic injuries with large tissue and bone damages.     

Cement use in total knee arthroplasty: 40 versus 80 grams

BackgroundStudies of cement use in total knee arthroplasty (TKA) have historically addressed mechanical properties and application strategies. Recently, cement technique has been studied as a means to reduce cost. We transitioned from opening two bags (80 grams) of cement to one bag (40 grams) of cement for primary TKA to improve cost efficacy. This study investigates the radiographic outcome and cost of TKAs performed with 40 versus 80 grams of cement.MethodsTKAs from January 2017 to January 2019 were evaluated. Cement mantle and implant alignment were assessed per the Modern Knee Society Radiographic Evaluation System at four months by three blinded reviewers. Data was analyzed according to quantity of cement used. Cement mantle quality at 16 implant zones was compared. Cost was evaluated.Results163 patients (age 66.8 yrs. +/− 8.9, 51.5% female) underwent TKA with 80 grams of cement, while 142 patients (age 67.1 yrs. +/− 9.3, 56.3% female) underwent TKA utilizing 40 grams of cement. There was no significant difference in cement mantle quality. The most common zone of cement deficiency was the femoral posterior flange (9% in 40 gram group versus 4% in 80 gram group, p value = 0.08). There was no difference in implant size. Cost saving was calculated at $7,810 for the 40 gram group.ConclusionThere was no difference in radiographic cement mantle appearance between primary knees performed with 40 or 80 grams of cement. Cement usage represents a target for cost saving and opportunity to increase the value of primary TKA. Based on the current incidence of TKA in the United States, cost savings could exceed 33 million dollars annually.     

骨质疏松绵羊腰椎膨胀式椎弓根螺钉与骨水泥强化椎弓根螺钉固定稳定性的动态比较研究

【摘要】 目的：比较骨质疏松绵羊腰椎膨胀式椎弓根螺钉（expansive pedicle screw,EPS）与骨水泥强化椎弓根螺钉（polymethylmethacrylate-augmented pedicle screw,PMMA-PS）固定的动态稳定性。方法：8只健康成年雌性绵羊,体重55.7±5.6kg,年龄5.5±0.7岁。行双侧卵巢切除术（去势手术）后1个月开始连续肌肉注射甲基强的松龙（0.45mg/kg/d）10个月,在建模前、激素注射结束后1个月（建模后）测量绵羊腰椎的骨密度（bone mineral density,BMD）,BMD显著下降（>25%）时为骨质疏松动物模型成功建立。建模后将每只骨质疏松绵羊腰椎（L1~L6）随机分为3组,每组2个腰椎。普通椎弓根螺钉（conventional pedicle screw,CPS）组,直接拧入CPS;PMMA-PS组,向钉道内注入聚甲基丙烯酸甲酯（PMMA,1.0ml）后拧入CPS;EPS组,直接拧入EPS。螺钉置入术后6周和12周各处死4只绵羊,取出腰椎,剔除标本周围软组织,自各椎间盘处离断,游离成单个椎体。每个腰椎随机选择一侧的螺钉行轴向拔出实验,将椎体固定于MTS 858生物材料实验机上,沿椎弓根螺钉长轴方向以5mm/min的加载速度进行轴向拔出实验,测量螺钉的最大轴向拔出力（the maximum pullout strength,Fmax）和能量吸收值（energy absorbed value,EAV）。结果：建模前、后绵羊腰椎的BMD分别为1.14±0.10g/cm2和0.83±0.07g/cm2,建模后BMD显著下降（P<0.05）,平均为27.2%（25.4%~28.9%）,骨质疏松绵羊模型成功建立。置钉术后6周EPS组和PMMA-PS组的Fmax分别为1252.13±203.51N和1426.38±235.75N,EAV分别为2.48±0.45J和2.84±0.55J,均显著高于CPS组（827.88±139.22N和1.66±0.30J）（P<0.05）;置钉术后12周EPS组和PMMA-PS组的Fmax分别为1518.88±256.81N和1472.75±248.65N,EAV分别为3.09±0.59J和2.95±0.60J,均显著高于CPS组（906.63±152.50N和1.80±0.35J）（P<0.05）;置钉术后6周、12周EPS组的Fmax和EAV与PMMA-PS组比较差异均无统计学意义(P>0.05)。置钉术后12周CPS组和PMMA-PS组的Fmax和EAV与同组置钉术后6周比较无显著性变化（P>0.05）,置钉术后12周EPS组的Fmax和EAV较同组置钉术后6周均有显著性提高（P<0.05）。结论：与CPS相比,EPS可显著提高螺钉在骨质疏松绵羊腰椎中的稳定性,并达到了与临床常用的PMMA-PS近似的固定效果。     

添加不同类型、比例的显影剂后骨水泥性能的变化

目的探讨添加不同类型、比例的显影剂后骨水泥(聚甲基丙烯酸甲酯,PMMA)聚合过程的变化,X线密度和抗压强度等生物力学的差异。方法用非离子碘造影剂和纯硫酸钡粉作显影剂分别加入PMMA,按粉∶液∶钡粉比例分别为15∶10∶3,15∶10∶1.5和粉∶液∶非离子碘造影剂分别为15∶10∶5,15∶10∶3组成4个实验组,用粉∶液比例为15∶10为对照组,每组8份,在体外测试其聚合过程;并制成相同大小的PMMA圆柱体40节,每组8份。结果添加硫酸钡粉后PMMA的聚合时间延长60～120s,15∶10∶3组平均延长约120s,添加非离子碘造影剂的2组则聚合过程无明显影响。添加硫酸钡粉或非离子碘造影剂后PMMA的最高聚合温度均有显著性差异;与对照组相比,4个实验组的X线密度有显著性差异,以15∶10∶3添加纯钡粉的PMMA组显影最强;加入非离子碘造影剂后PMMA最大抗压强度降低25%～31%(P<0.05),而加入纯钡粉的PMMA的最大抗压强度无显著变化。结论PMMA中加入一定比例的纯硫酸钡粉可延长聚合时间,而加入一定比例的非离子碘造影剂对聚合时间无明显影响;添加这两种显影剂后均可提高PMMA的X线显影能力,而以15∶10∶3添加纯钡粉的PMMA组显影最强;加入一定比例纯钡粉对PMMA的最大抗压强度无显著影响。     

聚甲基丙烯酸甲酯骨水泥对心血管系统影响及其预防的文献分析

目的综述关节置换术中聚甲基丙烯酸甲酯骨水泥对“血管系统的影响及预防措施，为其安全性评价和监管提供依据。方法对检索到的国内骨水泥文献筛选归纳并进行描述性分析。结果关节置换术中骨水泥易产生心血管系统并发症，导致血压下降、心律失常、血栓、肺栓塞等。结论文献分析结果表明，骨水泥的临床应用存在一定的安全性问题，建议临床医生谨慎使用。     

椎体成形术应用不同填充材料治疗骨质疏松椎体压缩性骨折的实验研究

目的通过用不同填充材料对骨质疏松兔的椎体成形,进而对行椎体成形术后椎体的生物力学行动态观察,从而得出相关结论,为临床应用提供理论基础。方法选用5个月龄新西兰纯种雌性兔60只,随机选12只作为正常对照组(A组),剩余的48只使用去势法造成骨质疏松模型后随机分成四组,每组12只。模型对照组(B组);聚甲基丙酸甲酯骨水泥(PMMA)组(C组);自固化磷酸钙骨水泥(瑞邦骨泰,CPC)组(D组);骨形态发生蛋白(BMP)和CPC组(E组)。解剖出椎体后直视下穿刺,按组别分别注入上述填充剂,每只进行3个椎体(L4、L5、L6)。分别于术后当时、8周和16周取椎体标本,行X线检查,并测定不同时间点椎体的轴向抗压强度实验。结果①术后当时拍X线片,除PMMA组有1例可见骨水泥渗漏入椎管内,其余均未见渗漏。术后8周和16周分别拍X线片,可见手术椎体密度较其他椎体和模型对照组椎体均高,与正常对照组相仿。②术后当时C组的抗压强度明显高于其他组(P<0.01),A组抗压强度次之,高于B组(P<0.01)、D组(P<0.01)和E组(P<0.01),而B、D和E组间则差异无统计学意义(P>0.05)。术后8周,C组抗压强度有所下降与术后当时相比差异无统计学意义(P>0.05),D和E组抗压强度有所上升(P<0.01),B组抗压强度明显低于其他组(P<0.01)。术后16周,C组抗压强度持续下降与A、D和E组相比差异无统计学意义(P>0.05),D和E组抗压强度继续上升(P<0.01),B组抗压强度继续下降(P<0.01),与其他各组差异有统计学意义(P<0.01)。结论CPC和CPC/BMP虽然具有较好的生物学性能,并且有较为广阔的应用前景,但在临床实际应用中,尤其在治疗骨质疏松脊柱压缩骨折时,尚不能完全取代PMMA。     

Evaluation and treatment of pelvic metastases

Advances in systemic treatment of cancer have improved patients' survival and increased the number of patients presenting with metastases of the pelvic ring. Pelvic metastatic lesions may cause severe pain and functional disability. A multidisciplinary approach is fundamental for the management of these lesions. Lesions of the pelvis not directly involving the hip joint such as the ischium, pubis or sacroiliac area can generally be treated non-operatively with radiation alone or using minimally invasive procedures of radiofrequency ablation, cryosurgery and percutaneous osteoplasty. Periacetabular destructive lesions may require total hip replacement with reconstruction of the acetabulum dependent on the extent of the defect. Operative treatment should restore the mechanical stability of the hip joint, and preserve the mobility, independence and comfort of these patients.     

注射型磷酸钙骨水泥在椎体成形术中的组织学研究

目的 模仿椎体成形术观察注射型磷酸钙骨水泥(CPC)／聚甲基丙烯酸甲（polymethylmethacrylate，PMMA)植入椎体后的微观结构变化。方法 将PMMA和CPC植入到犬椎体，通过X线、CT、光镜、扫描电镜观察二种材料与椎体界面间的微观结构变化。结果 PMMA与椎体之间的结合是单纯的机械连接未能达到生物机械固定，CPC与骨界面间无排异反应的表现，是直接的骨小梁与生物材料之间的生物连接，CPC与椎体之间的结合是生物连接可达到生物机械固定的目的。结论 磷酸钙骨水泥是椎体成形术中治疗胸腰椎爆裂骨折一种比较理想的材料。