胸腰段脊柱骨折定量影像学

描述影响胸腰段脊柱不同类型骨折,以及指导脊柱骨折治疗的不同分类及关键影响因素.目前脊柱骨折分类以Denis三柱模型为基石,包括压缩性骨折、爆裂性骨折、屈曲牵张骨折和骨折伴脱位.骨折分类系统包括胸腰椎损伤分类和严重程度评分(Thoracolumbar Injury Classification and Severity Score,TLICS)系统和AO脊柱胸腰椎损伤分类和严重程度评分(AOSpine-TLICS).正确分类需要定量成像方法,采用多个测量指标来评定其属于不同TLICS或AOSpine-TLICS类型.如果TLICS评分＞4或者AOSpine-TLICS评分＞5,则患者需要手术治疗.本文重点描述X线片、CT及MRI影像表现和测量参数,包括爆裂性骨折患者中椎体楔形变成角和压缩性骨折椎体高度丢失百分比、椎弓根间距和腰椎管狭窄程度以及一些严重骨折(如屈曲牵张骨折、骨折伴脱位)患者的椎体位移和棘突间距增加.通过图解和影像案例展现这些影像学特征和相关参数.     

胸腰椎爆裂性骨折模型

爆裂性骨折是最为常见的一种胸腰椎损伤。该损伤常伴有神经功能损害,遗留各种后遗症,给家庭和社会造成很大的负担。生物力学研究能使我们更好地理解胸腰椎爆裂性骨折的损伤机制、骨折稳定性、骨折复位机制及内固定的固定效果等情况。进行该类研究的前提是建立一个合理的爆裂性骨折模型。作者结合有关文献对建立胸腰椎爆裂性骨折模型的相关问题做一综述。     

人体胸腰椎体几何学测量及生物力学特性实验研究

研究水下爆炸产生的舰船冲击载荷导致舰船人员脊柱损伤的生物力学特性。分别从10具健康成年男性尸体上截取完整的胸腰椎,然后剔除不需要的软组织,并从胸、腰椎上仔细分离出各个自由椎体,对每个椎体上下两个端面处理后进行静态和动态压缩试验研究。从胸椎T₁至腰椎 L₅,随着椎体在脊柱位置上的下降,椎体的横截面积和体积逐渐增加,每个椎体所承受的动态和静态压缩破坏载荷也逐渐增加。计算动态应力强度与静态应力强度的比值,胸椎平均为1.51,腰椎平均为1.46。胸腰椎体面积和体积与其所本身所能承受的载荷变化趋势与人体承载能力的规律相一致,它反映了舰船冲击载荷造成船员胸腰椎损伤的机制及其损伤特性。     

椎弓根钉固定与椎体成形术治疗爆裂型骨折的生物力学研究

目的:评价用椎弓根钉系统固定并同时经椎弓根人工骨椎体成形术治疗胸腰椎爆裂性骨折的生物力学效果,为临床术式选择提供生物力学依据.方法:采用12具国人新鲜脊柱标本(T11～L3),预损伤后压缩法模拟失去前柱支持,完全不稳的L1椎体爆裂性骨折.实验分完整状态组、椎弓根钉同定组和椎弓根钉同定并椎体成形术组.测试标本前屈,后伸,左、右侧弯及左、右轴向旋转状态下同定节段(T11～L3)的运动范围(ROM)以及极限载荷,并计算刚度,进行统计学处理,比较各组间差异.结果:椎弓根钉同定并椎体成形术与单纯椎弓根钉固定两种手术方式进行比较.在屈伸、左右侧弯时,二者运动范围之间的差异无统计学意义,而在轴向旋转时,前者[左旋:(72.42±16.33)%,右旋:(70.30±1 1.58)%]运动范围小于后者[左旋:(106.92±12.0)%,右旋:(105.02±14.31)%](p＜0.05).极限载荷和刚度之间比较,前者均大于后者(P＜0.05).结论:采用椎弓根钉固定并椎体成形术治疗胸腰段爆裂型骨折,能够提高生物力学稳定性.稳定效果要优于单纯的后路短节段椎弓根螺钉内同定,同时也可以增加固定节段承受的极限载荷和刚度.     

胸腰椎爆裂性骨折体位复位的效果及影响因素研究

目的探讨胸腰椎爆裂性骨折后入路术前体位复位的效果以及影响因素。方法回顾性分析2013年8月至2016年2月收治的144例胸腰椎(T11~L2)爆裂性骨折伴脊柱畸形后型体位复位患者的临床资料,收集性别、年龄、体质指数以及临床和影像学资料。比较复位前后病例的Cobb氏角以椎体压缩的变化,利用单因素分析和多元logistics回归分析明确体位复位不完全的影响因素。结果体位复位的病例Cobb氏角与未复位相比差异无统计学意义(P0.05),椎体前缘压缩率由(0.43±0.12)%下降为(0.27±0.09)%,椎体后缘压缩率由(0.1±0.06)%下降为(0.07±0.03)%,差异有统计学意义(P0.05)。术前椎体压缩率为显著的影响因素,其优势比(OR)值分别为4.58[95%CI(1.42,20.15)]和2.31[95%CI(1.09,21.83)](P0.05)。结论体位复位对于胸腰椎爆裂性骨折具有明显的治疗作用,但术前椎体压缩率过大会导致治疗效果不佳。     

经皮椎体成形术/后凸成形术治疗骨质疏松性胸腰椎压缩性骨折

目的:评估经皮椎体成形术治疗多节段骨质疏松性胸腰椎压缩性骨折的临床疗效.方法:采用经皮椎体后凸成形术(PKP)或经皮椎体成形术(PVP)治疗多节段骨质疏松性胸腰椎压缩性骨折患者17例;比较手术前后椎体前柱及中柱高度以及Oswestry功能障碍指数(ODI)和疼痛视觉模拟评分(VAS)评分,根据Nakai标准分析手术疗效.结果:本组手术顺利,手术后椎体前柱及中柱高度均大于手术前,差异有统计学意义(P＜0.05).术后随访6～42个月.手术前后ODI和VAS评分较术前明显降低(P＜0.01),按Nakai标准评价:优9例,良5例,可2例,差1例,优良率82.35%(14/17).结论:经皮椎体后凸成形术或经皮椎体成形术治疗多节段骨质疏松性胸腰椎压缩性骨折创伤小,疗效满意.     

放射线摄影和CT后处理技术在腰椎外伤中的应用比较

腰椎外伤性骨折中以脊柱爆裂性骨折为常见,好发于胸腰段.收集我院胸腰椎爆裂性骨折60例,多层螺旋CT扫描后在AW4.0工作站进行多平面重建(MPR),表面遮盖重建(SSD),最大密度投影(MIP)后处理.分析其图像特点,探讨螺旋CT三维重建在胸腰椎爆裂性骨折中的应用价值.     

Edwards套棒方法治疗胸腰段脊柱不稳定损伤的生物力学实验研究

本文报告Edwards套棒装置及单纯Harrington分离棒治疗胸腰椎不稳定损伤的力学实验研究结果。取成年猪新鲜胸腰椎脊柱6具,切断前纵韧带、椎间盘纤维环、后纵韧带,造成前中柱不稳定损伤15处。测力传感器固定于椎体前缘并骑跨损伤处,使之检测纵向复位力。单侧内固定装置固定。实验结果表明:单侧Edwards套棒装置产生纵向复位力量89N,较Harrington分离棒48.7N提高82.7％(P<0.0005);二种内固定装置分别用于胸、腰椎时,纵向复位力均无显著差异(P<0.05),表明胸段肋骨对纵向复位力无影响。生物力学分析,纵向复位力与横向前推力成正比例关系,增大内固定装置对伤椎的横向前推力,可提高纵向复位力量。同时其它学者也报告Edwards套棒装置具有良好的脊柱三维稳定作用。所以,作者认为Edwards套棒装置集对脊柱骨折复位与稳定于一体,是理想的内固定装置。     

胸腰椎爆裂性骨折损伤机理的生物力学研究

本研究采用脊柱活动节段的三维有限元模型分析了脊柱在直立位、前屈位和后伸位的应力分布情况。结果表明上,椎弓根以及椎体后上方与椎弓根相邻部分为应力集中区域。这一结果提示胸腰椎爆裂性骨折的损伤机理与脊柱的应力集中有关。     

椎弓根螺钉内固定联合椎体成形修复单节段胸腰椎骨质疏松性爆裂性骨折

背景：对于椎管内有骨块占位的骨质疏松性胸腰椎爆裂性骨折,单纯椎体成形术难以解除椎管内占位及纠正脊柱后凸畸形,且骨水泥渗漏发生率高,使其成为其应用的相对禁忌证,而传统椎弓根螺钉系统固定存在手术创伤大、螺钉松动及椎体高度丢失等问题。 目的：观察经肌间隙入路短节段椎弓根螺钉内固定联合椎体成形治疗单节段胸腰椎骨质疏松性爆裂性骨折的疗效。 方法：回顾分析经肌间隙入路短节段椎弓根螺钉内固定联合椎体成形治疗单节段胸腰椎骨质疏松性爆裂性骨折患者31例。内固定后通过疼痛目测类比评分评估腰背部疼痛情况、ODI评分评估腰背部功能情况、SF-36健康调查评分表评估生活质量、胸腰椎正侧位片评估伤椎椎体前缘高度比值、伤椎Cobb角改善情况、Frankel评分评估神经功能情况及并发症。 结果与结论：内固定置入过程均顺利完成,未发生脊髓神经损伤。所有患者随访12-36个月,平均24.5个月,伤椎均达满意复位,平均伤椎椎体前缘高度及Cobb角得到明显改善,腰背部疼痛明显缓解,腰背部功能明显改善,生活质量明显提高,以上所有指标治疗后均显著改善,与治疗前比较差异有显著性意义(P < 0.05),内固定后1周和内固定后1年比较差异无显著性意义(P > 0.05)。内固定后2例患者出现骨水泥渗漏,其中椎体前缘及椎间隙处少量骨水泥渗漏各1例,但均无临床症状。随访期间,无内固定松动、断裂等,无新发骨折。说明联合应用后路经肌间隙入路短节段椎弓根螺钉内固定及伤椎椎体成形,不仅能有效恢复并维持伤椎椎体高度及强度,重建脊柱稳定性,明显缓解腰背部疼痛,还可以使患者获得满意的腰背部功能,显著提高生存质量,是治疗伴椎管内占位的骨质疏松性胸腰椎爆裂性骨折的有效方法。中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程全文链接：     

Modes of Inheritance of Errors of Refraction

Eighteen families in which both parents had refractions within the range of +4·0 D to −4·0 D and axial lengths seen in emmetropia (22·3-26·0 mm) showed coefficients of correlation of the order 0·5 indicative of polygenic inheritance. Such coefficients were seen for axial length (0·407) and for the cornea (0·487), but not for the lens (which is known to be yoked to the axial length). No such coefficients were seen in 19 families in which one of the parents had axial length outside the emmetropic range (nine families with long axes and 10 with short axes).

The pattern of polygenic inheritance for emmetropia (completely correlated optical components) and errors of refraction up to 4·0 D (inadequately correlated components: correlation ametropia) follows that seen in stature and other measurable characters. In contrast the high refractive errors with their abnormal axial lengths (component ametropia) are—like the extremes in stature—pathological anomalies with monofactorial inheritance.

     

Recovery of responsiveness of cells of lateral geniculate nucleus of rat

1. Recovery of responsiveness of single cells in lateral geniculate nucleus of rat has been determined in both P and I cells. There are three types of recovery curve among P cells; (a) early recovery, (b) early partial recovery followed by depression and then complete recovery, (c) prolonged depression followed by cyclic recovery. Type (c) is by far the commonest recovery curve. In contrast to the spike in a P cell, the synaptic potential recovers to its full amplitude in about 20 msec. All I cells exhibit similar rapid recovery curves after a prolonged depression.2. Conditioning stimuli applied to visual cortex also produce a prolonged depression in most P cells but I cells can be re-excited at short intervals from cortex. Decortication does not prevent the prolonged depression of the multineuronal response produced by optic nerve stimulation.3. A neuronal model is proposed to explain these observations. It is supposed that I cells (interneurones) are innervated by axon collaterals of the P cells (principal cells, projecting to visual cortex) and that the I cells exert an inhibitory influence on the P cells.     

Level of functioning of siblings and parents of probands of varying degrees of retardation

A further analysis of already published data supports the position that retardates of low ability level less frequently have retarded siblings, retarded parents, and parents low in occupational level than do retardates higher in ability level. The analysis supports the position that there are two types of retarded individuals, persons retarded as a result of gene or chromosomal anomalies, brain injury, etc., who more frequently occur in the lower-level retardate group, and persons whose retardation represents polygenic segregation, who more frequently occur in the higher-level group.     

Analysis of two types of dopaminergic responses of neurons of the spinal ganglia of rats

It was established, in experiments on isolated spinal ganglia of adult rats in concluons of intracellular recording, that dopamine (1 M/liter) elicits depolarized responses in 61% of neurons, hyperpolarized in 20% of neurons, and depolarized-hyperpolarized in 19% of neurons. The depolarized responses are associated with the activation of D₁ dopamine receptors, and are governed by the shift of cAMP-dependent cation (sodium) channels to the conducting state. The hyperpolarized responses are triggered by the activation of D₂ dopamine receptors, which by means of HTP-binding protein convert the potassium channels to the conducting state. The change in the polarization of neurons with the action of dopamine influences their electrical excitability variously.Translated from Fiziologicheskii Zhurnal SSSR imeni I. M. Sechenova, Vol. 76, No. 6, pp. 739–745, June, 1990.     

局部注射辛伐他汀对骨质疏松大鼠股骨髁骨小梁的改建效应

背景：局部注射具有成骨作用的辛伐他汀,可显著增加骨质疏松大鼠股骨颈及股骨髁部的骨密度及力学强度,分析局部注射辛伐他汀对股骨髁骨小梁的影响。 目的：进一步研究骨质疏松大鼠股骨内局部注射辛伐他汀对股骨髁骨小梁的影响。为将辛伐他汀应用于临床骨质疏松局部治疗提供实验基础。 方法：18只雌性SD大鼠双侧卵巢切除后3个月,制备大鼠骨质疏松模型。实验大鼠随机数字表法均分为3组,分别在实验大鼠的右侧股骨髓腔内单次注射辛伐他汀溶液5 mg、10 mg,对照组单纯注射空白载体。分别在注射后1个月处死大鼠并取材。Micro-CT扫描并定量分析骨组织形态变化。 结果与结论：给药后1个月,Micro-CT扫描结果显示,辛伐他汀治疗组的骨微结构参数如骨皮质厚度、骨小梁密度及连接率明显优于对照组。说明疏松骨骼单次注射小剂量辛伐他汀可显著促进股骨髁部骨小梁改建,改善骨骼微结构,可为强化局部、防治骨质疏松骨折的新选择进一步提供实验基础。