骨水泥椎体强化椎弓根钉置入对骨质疏松脊柱生物力学稳定性的影响

背景：伴有骨质疏松患者的脊柱内固定松动、脱落是脊柱外科一个复杂而棘手的问题。用聚甲基丙烯酸甲酯骨水泥强化椎弓根螺钉可增加伴有骨质疏松患者的椎弓根螺钉防止椎弓根钉的松动及脱落。 目的：评价聚甲基丙烯酸甲酯骨水泥椎体强化后椎弓根钉固定对不稳定骨质疏松脊柱的生物力学稳定性影响。 设计、时间及地点：体外生物力学实验,于2008-03在上海大学生物力学实验室完成生物力学实验。 材料：12具新鲜老年女性尸体T10~L3椎体标本,制成T12、L1间的不稳定模型,采用椎弓根螺钉系统固定。 方法：将标本按照不同的处理方式分为4组。①对照组：为完整标本,只进行生物力学性能的测试。②一次固定组：对照组测试后随机选取6具不稳定模型,行T11~L2椎弓根钉固定。③二次固定组：一次固定组标本完成稳定性测试后,取出所有椎弓根螺钉,分别用注射器向T11~L2椎弓根钉道注入配制好的聚甲基丙烯酸甲酯骨水泥骨水泥2.0 mL后再次拧入螺钉固定。④强化固定组：将余下的6具标本于T11~L2双侧椎弓根分别以直径3.5 mm的钻头导孔,沿孔道插入直径3.5 mm的穿刺导管,插入深度为40 mm,用加压注射器经导管缓慢向椎体内加压注射配制好的聚甲基丙烯酸甲酯骨水泥3.5 mL后拧入螺钉固定。 主要观察指标：进行轴向压缩、前屈/后伸、左/右侧弯、左/右旋转7项非损伤性加载,比较上述4组不同状态下脊柱的相对运动范围变化。 结果：与一次固定组比较,二次固定组及强化固定组脊柱的相对运动范围增加(P < 0.05),强化固定组与二次固定组组间比较,差异无统计学意义(P > 0.05)。 结论：椎体成形强化椎弓根钉固定及钉道强化固定均可明显增强不稳定骨质疏松脊柱的稳定性。     

腰椎新型动态固定系统腰椎后路固定融合的生物力学性能

背景：脊柱融合固定过程中，用于后路固定的钉棒系统由于造成相邻椎体、椎间盘及椎间关节的应力改变以及反常活动，会导致固定融合后相邻节段的退行性变加速。 目的：在腰椎后路固定融合过程中采用新型动态固定系统，验证动态固定系统在固定术后的即刻生物力学性能，并与传统固定系统相比较。 设计、时间及地点：对照实验，于2007-11/12在上海大学生物力学研究所完成。 材料：10具新鲜小牛T12~S5脊柱标本。 方法：模拟人体生理运动情况，即轴向压缩、前屈、后伸、侧屈状态，并加上扭转状态测试。实验属稳定性实验，最大加载不超过125 N的生理载荷，无破坏性影响，故标本可重复使用。依实验进程标本分为4组，每组10具标本。先对每具标本进行生理状态测试，然后制成L5~S1滑脱腰椎失稳实验模型进行测试，之后行后路椎间融合椎弓根钉棒固定，分别采用传统钉棒和动态固定系统建立腰椎后路固定融合模型进行测试。实验过程中未出现标本破坏及内固定器械断裂失效等情况。 主要观察指标：生理载荷125 N时，生理状态、滑脱状态、传统钉棒固定及动态钉棒固定状态下腰椎的水平剪切刚度、轴向刚度及扭转强度。 结果：采用两种固定系统行后路固定椎间融合后，系统的稳定性均明显超过滑脱状态，达到或超过生理状态。对于临近（上位）节段的应变、位移等影响，传统钉棒系统明显超过生理状态（P < 0.05），而动态固定系统接近生理状态（P > 0.05）。 结论：采用腰椎动态固定系统行后路椎间固定融合后，其稳定性达到或超过正常生理状态，能够满足对临床固定手术后即刻稳定性的要求。与传统静态钉棒固定系统相比较，动态固定系统相邻椎体、椎间盘、椎间关节所承受的应力应变均明显降低，各项生物力学性能上均接近正常腰椎生理状态，不易产生邻近节段的退行性变，具有较大的优势。     

腰椎椎弓根螺钉系统断裂的三维有限元分析

背景：椎弓根螺钉系统已是最为常用的脊柱内固定器械，但其钉棒断裂在临床上仍时有发生。 目的：利用三维有限元分析腰椎椎弓根螺钉系统在临床中断裂的并发症，以期提高手术成功率。 设计、时间及地点：三维有限元分析，于2007-11/2008-03在南方医科大学珠江医院完成。 对象：选择1名成年志愿者，年龄27岁，身高174 cm，体质量63 kg，经X射线检查排除脊柱疾病。 方法：建立腰椎椎弓根螺钉系统内固定的三维有限元模型，并分别施加压缩、前屈、后伸、侧屈及旋转5种生理载荷，对比分析不同载荷下螺钉、连接棒的应力分布。 主要观察指标：不同载荷下螺钉、连接棒各部分的应力。 结果：椎弓根螺钉系统各部分于垂直压缩下的应力远小于前屈、后伸、侧屈及旋转时所受压力。垂直压缩下应力主要集中在螺钉近棒段，而在前屈、后伸、侧屈及旋转时应力主要集中在连接棒上。 结论：椎弓根内固定系统设计及类型的选择，术中的规范操作，术后康复活动的指导及保护、适时取出内固定等对预防其断裂均十分重要。     

5000/两种固定器固定脊柱骨折脱位生物力学分析

目的 从生物力学角度对临床应用治疗脊柱骨折脱位的二种固定器进行定量分析,为临床提供力学参数。方法 模拟胸腰椎骨折脱位分别以钢板,椎弓根钉固定,分别进行前屈、后伸、左旋转、右旋转、压缩实验。结果 得出了各组标本前屈、后伸、压缩载荷—位移数据,还得出了各组标本扭转时扭矩和扭转角数据。结论 椎弓根钉组和钢板组压缩位移差异不显著P>0.05,椎弓根钉组前屈、后伸、位移小于钢板组,P<0.05,椎弓根钉组左、右扭转角度小于钢板组,P<0.05.     

齿轮撑开式脊柱复位固定板装置的研制

背景: 目前临床应用的脊柱后路复位固定的钉棒系统存在一定程度的生物力学的缺陷,钉板系统更适合在患者中广泛使用。 目的：依据中国人脊柱的椎弓根间距、弧度、椎体及椎间隙高度的影像学测量结果,研制一种新型的脊柱后路复位内固定板装置。 方法：测量129例门诊查体的正常者的胸腰椎数据。依据影像学测量的结果,并在复习文献的基础上,对新型脊柱复位内固定器进行图纸设计及形状设计。取18具新鲜小牛腰椎标本随机分为实验组给予行齿轮撑开式脊柱复位内固定板装置固定,CD及Steffee组分别用CD及Steffee钢板固定,测量标本在受到轴向压缩、前屈、后伸及侧屈载荷状态下的位移、应变、刚度和破坏性能等测试,结果进行统计学处理。 结果与结论：齿轮撑开式脊柱复位内固定装置(GDP)能较好地满足人体强、刚度的要求。GDP组测得椎体固定的强度和刚度均比对照组CD和Steffee钢板系统优越(P < 0.05),腰椎的扭转力学性能比CD,Steffee钢板内固定分别高出13%和14%,腰椎的极限力学性能测试结果显示GDP能承载载荷,比CD,Steffee钢板更大(P < 0.05)。说明齿轮撑开式脊柱复位固定板装置的设计符合中国人脊柱的解剖规格,生物力学稳定性良好,可以显著促进椎骨骨折的愈合,防止脊椎后凸的复发和高度的丧失。     

伤椎椎弓根置钉治疗胸腰椎压缩性骨折的三维有限元分析*

背景：有文献报道伤椎置钉技术较传统4钉跨阶段固定具有更强的牢固性,可有效避免内固定的松动断裂,但其生物力学机制研究尚显不足。 目的：构建脊柱胸腰椎单纯压缩性骨折的三维有限元模型,探讨伤椎附加椎弓根螺钉置入治疗胸腰椎压缩性骨折的生物力学效应。 方法：将一T12椎体压缩性骨折患者脊柱胸腰段超薄CT扫描数据输入Mimics软件中,构建T12椎体压缩性骨折的有限元模型,在此模型基础上模拟伤椎置6钉和跨节段4钉内固定,对两个模型分别施加垂直压缩、前屈、后伸、左屈及右旋载荷。 结果与结论：两组固定模式各种载荷下的应力均集中在螺钉根部,在垂直载荷下,螺钉的应力最小,右旋和左屈载荷下的应力最大;在垂直压缩、前屈、后伸、左侧弯及右旋运动下,上位螺钉较下位螺钉应力大(P < 0.05)。伤椎置6钉固定组螺钉应力较跨节段4钉固定组小(P < 0.05)。两组T11椎体最大位移无差别。表明伤椎附加椎弓根螺钉置入可以优化内固定的载荷,减少断钉率。     

E经后路椎弓根钉固定结合硫酸钙椎体成形术治疗胸腰椎压缩性骨折的生物力学研究

背景：经后路复位椎弓根螺钉固定治疗胸腰椎压缩性骨折,常遗留脊柱前柱骨质缺损,其结果可导致术后内固定的松动、断裂及椎体高度的丢失。为避免此类并发症的发生,骨折椎体的强化必须的。目前临床应用硫酸钙骨水泥进行椎体成形术是一新的治疗方法,有必要对其治疗中的生物力学特性进行研究。 目的：探讨经后路椎弓根螺钉固定结合硫酸钙椎体成形术治疗胸腰椎压缩性骨折的生物力学性能。 设计、时间及地点：随机对照研究,2009年3月在上海大学生物力学研究所进行实验。 材料：15具新鲜小牛脊柱标本,分割成功能节段T11-L1,剔除肋骨及附着的肌肉组织,保留椎间韧带及关节突完整。脊柱穿刺针（美国Wright公司）,针芯直径3.2mm,其尾部可与配套注射器连接;硫酸钙骨充填物为美国Wright医疗器械公司的MIIG-X3系列;万能材料试验机及其他必要的测量仪器由上海大学生物力学研究所提供。 方法： 15具新鲜小牛T11-L1脊柱功能单位（Function spine unit FSU）,随机分3组：正常完整标本组（A组）,后路复位椎弓根钉固定组（B组）,后路复位椎弓根钉固定结合硫酸钙椎体成形组（C组）。B、C组标本制成T12椎体屈曲压缩性骨折模型,分别采用后路复位椎弓根钉固定及后路复位椎弓根钉固定结合硫酸钙椎体成形。3组标本在WE-10型万能材料试验机进行生物力学测试。收集实验数据进行统计学处理,进行组间比较。 主要观察指标：加载不同级别载荷,在轴向压缩、屈曲、伸展、侧屈4重工况下检测FSU的载荷-应变关系、载荷-位移关系、强度、刚度及抗扭等生物力学性能,收集实验数据。 结果： 胸腰椎载荷-应变及载荷-位移关系呈线性变化,C组的椎体和椎间盘平均应变比B组低14%和12%,比A组的低21%和13%;3组标本位移比较,C组位移分别比B、A组减少25%和37%。胸腰椎FSU的椎体和椎间盘的强度,C组比B组高14%和24%,比A组高13%和20%;胸腰椎刚度,C组比B、A分别高44%和53%。胸腰椎FSU最大抗扭强度,C组分别比B、A组高18%和30%,扭转刚度C组分别比B、A组高30%和40%。以上数据经统计学处理,差异均具有统计学意义（P＜0.05）。 结论：经后路椎弓根螺钉固定结合硫酸钙椎体成形术治疗胸腰椎压缩性骨折的生物力学性能是优越的,不但强度、刚度大,而且术后的胸腰椎体稳定,有利于减轻内植物的应力负荷,进而降低螺钉的松动、折断发生率及术后椎体高度的丢失。     

成人颈椎椎弓根螺钉在儿童腰椎应用的可行性*

背景：由于1~3岁幼年儿童椎体发育未完全成熟,各种解剖径线相对较成人小得多,尚无幼儿专用的椎弓根螺钉固定器械,现有能够利用的直径最小的椎弓根螺钉是用于成人颈椎侧块或椎弓根固定的钉棒系统。 目的：观察将成人颈椎椎弓根螺钉应用到成年猪颈椎与幼猪腰椎固定后的生物力学对比。 方法：将6具完整新鲜成年猪颈段C3~C6脊椎标本和6具完整8周龄新鲜幼猪腰段脊柱标本自椎间盘及关节处离断,游离成单个椎体,共54个椎体108侧椎弓根。按照标准操作将成人颈椎椎弓根螺钉分别安置在成年猪颈椎标本和幼猪腰椎标本的椎弓根上,应用生物力学方法测试螺钉的最大轴向拔出力。 结果与结论：颈椎标本最大轴向拔出力高于腰椎标本,但差异无显著性意义(P > 0.05);L1椎弓根螺钉的拔出力均值明显小于L3椎弓根螺钉的拔出力均值(P < 0.05);C5椎弓根螺钉的拔出力均值明显大于C3椎弓根螺钉的拔出力均值(P < 0.05);颈椎和腰椎标的骨密度差异有显著性意义(P < 0.01),椎体椎弓根力学数值与椎体骨密度之间存在线性正相关。说明取得了成人颈椎椎弓根螺钉在轴向拉力方面适应于幼儿腰椎的初步实验依据。     

伤椎后路椎弓根螺钉置入并椎体内植骨重建胸腰椎椎体的高度

背景：后路短节段经椎弓根内固定器械可使骨折达到近似解剖复位效果,明显提高疗效,但远期随访矫形度数丢失、内固定失败等并发症较普遍。 目的：探讨经伤椎椎弓根螺钉置入固定结合经椎弓根植骨治疗胸腰椎骨折的可行性。 方法：对73例胸腰椎骨折应用椎弓根钉棒系统后路伤椎一侧椎弓根螺钉置入内固定,对侧经椎弓根通道采用自体骨和同种异体骨行椎体内植骨。 结果与结论：73例随访6个月内均获骨性愈合,脊柱植骨融合率100%,无螺钉松动、折断。1例Frankel分级C级无变化,1例D级无变化,其余患者神经功能及腰背痛明显改善;置入后6个月损伤节段后凸平均Cobb角、伤椎椎体前缘高度、椎管前后径残留程度均较治疗前明显恢复。表明经伤椎椎弓根钉置入内固定结合经椎弓根植骨治疗骨折可获得满意复位,重建椎体高度,增强脊柱的抗压稳定性,减少内固定因应力过大造成的断钉、矫正丢失等并发症。     

可注射复合人工骨修复犬胸腰椎骨折后的轴向承压能力*★

背景：此前已有学者从组织学等多角度探讨并进行了可注射复合人工骨作为椎体成形填充剂的实验研究，还需要进一步从术后伤椎轴向承压能力方面探讨此种治疗方法的疗效，以取得在人体上难以得到的直观对比数据。 目的：观察在椎体成形术治疗犬胸腰椎骨折过程中植入可注射复合人工骨后伤椎的轴向承压能力。 设计、时间及地点：随机对照动物实验，于2008-09/2009-01在深圳市龙岗区中心医院外科动物实验室完成。 材料：脊柱矫形固定器钉棒Ⅰ型、Ⅱ型由天津正天医疗器械有限公司提供。参照尹庆水等提供的方法制备注射型复合人工骨，低温保存备用。其中珊瑚羟基磷灰石颗粒、重组人骨形成蛋白2冻干粉由解放军军事医学科学院提供，2%几丁糖溶液由解放军第二军医大学与上海其胜生物材料研究所联合研制。 方法：1岁龄普通级健康家犬20只，随机分为治疗组和对照组各10只，模仿高处坠落致胸腰段受到屈曲压缩暴力进行造模，治疗组采用椎弓根钉棒系统对伤椎进行复位后通过伤椎椎弓根注入复合人工骨行椎体成形治疗。对照组仅采用椎弓根钉棒系统对伤椎进行复位内固定。 主要观察指标：术后3个月处死动物，取伤椎及上下椎体段脊柱，在微电脑压力测试试验机上测量椎体中心点最大负载压强。 结果：实验组100%伤椎中心点负载压强与同个体上下椎体比较差异无显著性意义，恢复了轴向承压能力；而对照组有60%伤椎中心点负载压强与同个体上下椎体比较差异有显著性意义(P < 0.05)，未恢复轴向承压能力。 结论：采用椎弓根螺钉系统复位内固定及可注射人工骨椎体成形治疗胸腰椎骨折可能会有效地恢复术后伤椎抗轴压能力，从而提高手术成功率。     

Denervation study of synapses of organ of corti of old world monkeys

Fine structural characteristics of synapses in the spiral organ of Corti were examined, with reference to differences between inner and outer haircell systems, and to location of neurons of origin of efferent axons. Surgical interruption of crossed olivocochlear bundle, of vestibular nerve, of facial nerve, and excision of superior cervical ganglia were used to determine the pathways of efferent axons. Interruption of the vestibular nerve near the brainstem results in degeneration of all efferent terminals on outer hair cells. Mid-line lesions at, and caudal to, the facial colliculus result in degeneration of about half of these efferent terminals. Efferent synaptic bulbs to the inner hair-cell system are small, of the order of one micron, and form type 2 junctions with afferent dendrites. They tend to have more large dense-core vesicles (about 80 nm) than the large efferent terminals of the outer hair-cell system, and appear to be the terminals of axons in the habenula perforata, which exhibit varicosities laden with large dense core vesicles. The varicosities are unaffected by excision of the superior cervical ganglia. So far as our material can reveal, it appears that the varicosities in the habenula perforata do not survive vestibular root interruption, nor do the efferent processes in the internal spiral bundle or at the base of inner hair cells. Most interestingly, the afferent processes of the inner hair-cell system, as identified for example by their relation to pre-synaptic bodies in the inner hair cells, are subject to a trans-synaptic reaction after severance of the vestibular root. They undergo a dramatic cytological transformation, characterized by increase of volume, engorgement with microtubules, microfilaments, microvesicles of various sizes, and clusters of lysosomes. Thus, both the efferent and afferent terminals of the inner hair-cell system show marked cytological differences from the corresponding terminals of the outer hair cell system.     

Mechanism of action of tubocurarine on nicotinic cholinoreceptors of neurons of the sympathetic ganglia of rats

Tubocurarine (Tc) effect on membrane currents elicited by acetylcholine (ACh) was studied in isolated superior cervical ganglion neurons of rat using patch-clamp method in the whole-cell recording mode. The "use-dependent" block of ACh current by Tc was revealed in the experiments with ACh applications, indicating that Tc blocked the channels opened by ACh. Mean lifetime of Tc-open channel complex, tau, was found to be 9.8 +/- 0.5 s (n = 7) at -50 mV and 20-24 degrees C. tau exponentially increased with membrane hyperpolarization (e-fold change in tau corresponded to the membrane potential shift by 61 mV). Inhibition of the ACh-induced current by Tc (3-30 microM/1) was completely abolished by membrane depolarization to the level of 80-100 mV. Inhibition of ACh-induced current was augmented at increased ACh doses. It is concluded that the open channel block produced by Tc is likely to be the only mechanism for Tc action on nicotinic acetylcholine receptors in superior cervical ganglion neurons of rat.     

The effect of age of onset of PD on risk of dementia

Background Dementia occurs in the majority of patients with Parkinson’s disease (PD). Late onset of PD has been reported to be associated with a higher risk for dementia. However, age at onset (AAO) and age at baseline assessment are often correlated. The aim of this study was to explore whether AAO of PD symptoms is a risk factor for dementia independent of the general effect of age. Methods Two community-based studies of PD in New York (n = 281) and Rogaland county, Norway (n = 227) and two population-based groups of healthy elderly from New York (n = 180) and Odense, Denmark (n = 2414) were followed prospectively for 3–4 years and assessed for dementia according to DSM-IIIR. All PD and control cases underwent neurological examination and were followed with neurological and neuropsychological assessments. We used Cox proportional hazards regression based on three different time scales to explore the effect of AAO of PD on risk of dementia, adjusting for age at baseline and other demographic and clinical variables. Findings In both PD groups and in the pooled analyses, there was a significant effect of age at baseline assessment on the time to develop dementia, but there was no effect of AAO independent of age itself. Consistent with these results, there was no increased relative effect of age on the time to develop dementia in PD cases compared with controls. Interpretation This study shows that it is the general effect of age, rather than AAO that is associated with incident dementia in subjects with PD. Received in revised form: 22 December 2005     

Limits of deinstitutionalization--perspectives of relatives of psychiatric patients

After a hopeful beginning, the social process of the reintegration of those with severe mental illness has come to a standstill. I am led to wonder whether "the community" really wants to live together with people suffering from severe mental illness, and if so, how closely? As long as the medical treatment of mental illness provided by the general practitioners is fundamentally deficient, as they are not able to prescribe the necessary interventions--such as out-patient psychiatric nursing, and service providers in the out-patient sector are content with offering increasingly intensive forms of care for the less seriously ill at the cost of the Social Welfare System--the reintegration of those with serious mental illness remains an illusion--which is mainly to the benefit of providers of residential care in homes and hostels.     

Sense of coherence as a predictor of subjective state of health: results of 4 years of follow-up of adults

A number of cross-sectional population studies have shown that a strong sense of coherence (SOC) is associated with various aspects of good perceived health. The association does not seem to be entirely attributable to underlying associations of SOC with other variables, such as age or level of education. OBJECTIVE: The aim of the study reported here was to determine whether SOC predicted subjective state of health. METHODS: The study was carried out as a two-way panel mail survey of 1976 individuals with 4 years interval for two collections of data. The statistical method used was multivariate cumulative logistic modeling. Age, initial subjective state of health, initial occupational training level, and initial degree of social integration were included as potential explanatory variables. RESULTS: A strong SOC predicted good health in women and men. CONCLUSIONS: SOC can be interpreted as an autonomous internal resource contributing to a favorable development of subjective state of health. SOC data should, however, be regarded as complementary to and not a substitute for information already known to be associated with increased risk of future ill health.