寰椎骨折的生物力学分析

目的采用有限元方法,预测寰椎在不同位置条件下寰椎应力的分布,并以此推断可能出现的寰椎骨折类型。方法构建寰椎三维骨性结构,分析寰椎在中立、屈曲、后伸三种位置下应力分布状况。结果寰椎高应力在中立位时,出现在寰椎前部和双侧椎弓根;屈曲位时,分布在寰椎前部;后伸位时,存在寰椎前弓和双侧椎弓根。结论寰椎前弓和前结节交界处、前弓和侧块交界处、后弓和侧块交界处、后弓和后结节交界处是应力较为集中的部位,也是寰椎骨折容易发生的部位。骨折部位和骨折类型与寰椎损伤时所处的位置、寰椎几何形状、外力的方向以及寰椎的力学特征密切相关。     

新型成人后路寰椎骨折钉板复位内固定系统的设计

背景：目前临床上一直缺乏复位良好、操作简便的后路单节段固定治疗寰椎爆裂性骨折的内固定系统。目的：基于寰椎CT测量数据设计并优化一种符合人体局部解剖结构特征，操作简便且复位优良的新型后路寰椎骨折钉板复位内固定系统。方法：回顾性分析了347例成人的CT图像，在图像上依次测量内倾角0°经后弓侧块螺钉轨迹长度、最大内侧倾斜角与此时经后弓侧块螺钉轨迹的长度、寰椎椎动脉沟底部后弓高度、两侧经后弓侧块螺钉进针点距正中矢状面的距离、寰椎后弓半径、寰椎后结节至枕骨大孔后缘和寰椎后结节至枢椎椎弓上表面的距离，分析数据并设计优化一种符合人体解剖学特征的寰椎骨折复位内固定系统。结果与结论：(1)所有受试者两侧的内倾角0°螺钉轨迹长度、最大内倾角度、最大内倾角螺钉轨迹长度、寰椎椎动脉沟底部后弓高度、进钉点至正中矢状面距离、寰椎后弓外侧缘半径、寰椎后结节至枕骨大孔后缘距离、寰椎后结节至枢椎棘突上表面距离的差异均无显著性意义(P> 0.05)，上述各指标在男性与女性组间比较差异均有显著性意义(P <0.05);(2)研究成功设计了新型寰椎骨折复位内固定系统，并获得国家专利；该内固定系统适合寰椎后弓解剖学...     

记忆合金椎间融合器对腰椎节段稳定性的生物力学研究

目的 :评价植入记忆合金椎间融合器 (SMAcage)后腰椎节段的即时稳定性。方法 :8具青年男性新鲜尸体脊柱腰 3、4节段标本 ,制成包括正常腰椎、SMAcage和其它 3种不同类型椎间融合器在内的5种状态的试验模型。测试其前屈 ,后伸 ,左右侧屈和左右旋转方向的运动范围 (ROM )。结果 :植入SMAcage后各向ROM值分别为完整状态的 66%、84%、65 %和 12 5 %,在前屈和侧屈方向上较正常腰椎的稳定性明显提高 (P <0 .0 0 1) ;后伸方向一致 (P =0 .117) ;旋转方向则降低 (P <0 .0 0 1)。与其它 3种融合器的稳定性相比 ,在前屈、后伸方向一致 (P >0 .0 5 ) ;侧屈方向与 2种方形融合器无明显差别 (P =0 .12 2 ) ,高于螺纹状融合器 (P =0 .0 0 4) ;旋转方向与螺纹状融合器一致 (P =0 .861) ,高于 2种方形融合器(P <0 .0 5 )。结论 :SMAcage具有独特的构型和稳定机制 ,其生物力学稳定性高于一般螺纹状和方椎间融合器。     

椎弓根钉棒系统治疗不稳定性Jefferson骨折的生物力学分析

背景：目前后路寰枢椎椎弓根螺钉有取代Magerl技术趋势,成为治疗寰枢椎不稳的新标准术式。 目的：评价单、双侧椎弓根钉棒系统治疗不稳定性Jefferson骨折的力学稳定性,为临床应用提供实验依据。 方法：在6具完整枕骨颈椎(C0~4)湿润标本切断寰椎前后弓与侧块的联接部位,并切断寰椎横韧带,制成不稳定性 Jefferson骨折模型,分别安装单侧寰枢椎椎弓根螺钉系统和双侧寰枢椎椎弓根螺钉系统,通过摄像记录在1.53 N•m载荷下C1~2的三维运动,测定正常组、骨折模型组及各内固定组的三维运动范围,评价其重建寰枢椎即时稳定性的效果。 结果与结论：在屈伸、侧屈及轴向旋转的运动中,单侧寰枢椎椎弓根螺钉系统组的三维运动范围均明显大于双侧寰枢椎椎弓根钉棒系统组(P < 0.05)。提示在治疗不稳定性 Jefferson骨折时,双侧寰枢椎椎弓根钉棒系统内固定治疗稳定性好;单侧寰枢椎椎弓根螺钉系统固定效果不佳,尤其是抗旋转能力差,不能满足增强稳定性、植骨融合的要求,应尽量避免单独使用。     

单椎间椎弓根钉固定胸腰椎骨折生物力学评价

目的 通过单椎间与双椎间椎弓根钉固定术固定胸腰椎骨折的生物力学效果比较,评价单椎间固定的生物力学特点.方法 16具新鲜小牛椎体(T11～L3)用于实验,随机分为2组,用MTS机压缩法制作L1椎体爆裂骨折模型(按AO分型,A3.1).分别行单椎间与双椎间椎弓根钉固定,在脊柱三维运动试验机上模拟人体行屈伸、左右侧弯和旋转活动,测固定节段运动范围(ROM),行疲劳实验并再观察固定节段ROM.结果 单椎间固定组ROM稳定指数(SPI-ROM)小于双椎间组,但除前屈方向差异有统计学意义外(P=0.007),余均无明显差异(P＞0.05).抗疲劳性比较,在旋转和侧屈方向,双椎间组优于单椎间组(旋转:P=0.008;侧屈:P=0.02).结论 两种术式在重建脊柱骨折即刻稳定性方面,效果无明显差异.单椎间椎弓根钉固定术生物力学效果满足临床应用,但是,其在抗旋转、侧屈疲劳性方面逊于双椎间固定.     

两种寰椎侧块螺钉固定方法的可行性比较

背景：寰椎侧块螺钉固定技术按其入钉点的不同可分为寰椎后弓下侧块螺钉固定和经寰椎后弓侧块螺钉固定(又称寰椎椎弓根螺钉固定),这2种固定方法各有优缺点,以往缺乏关于2种寰椎侧块螺钉固定方法骨性解剖可行性的比较研究, 目的：以测量国人寰椎相关骨性解剖数据为依据,比较2种寰椎侧块螺钉固定方法的可行性。 方法：收集30例(60侧)成人颈椎病患者的寰椎螺旋CT扫描数据,利用CT工作站对数据重建,分别测量寰椎侧块螺钉固定的关键骨性解剖数据,适合行经寰椎后弓侧块螺钉固定的标准为寰椎椎动脉沟处后弓高度和宽度≥ 4 mm;适合行经寰椎后弓下侧块螺钉固定的标准为寰椎后弓下侧块高度≥ 4 mm。 结果与结论：寰椎椎动脉沟处后弓高度为(4.54±1.17) mm,椎动脉沟处后弓宽度为(8.69±1.12) mm,寰椎后弓下侧块高度为(4.98±1.07) mm。寰椎后弓椎动脉沟高度大于4 mm(适合经寰椎后弓螺钉固定组)有41侧,占68%;寰椎后弓下侧块高度大于4 mm(适合经寰椎后弓下侧块螺钉固定)有52侧,占87%,2组差异有显著性意义(P < 0.05)。提示经寰椎后弓下侧块螺钉固定较经寰椎椎弓根螺钉更具可行性。术前利用CT测量寰椎关键解剖结构数据对制定个性化手术方案具有重要意义。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：     

经口前路寰枢椎侧块关节融合器的力学稳定性评价

目的　评价经口前路寰枢椎侧块关节融合器在前路经口寰枢椎复位固定钢板（TARP）及后路寰枢椎椎弓根钉棒（后路C1-C2钉棒）固定下的力学稳定性,为临床应用提供理论依据。  方法　采用自行设计的经口前路寰枢侧块关节融合器,将6具新鲜上颈椎标本,随机分为完整对照组(M)、前路TARP+髂骨块组(A1)、前路TARP+cage组(A2)、后路C1-C2钉棒＋髂骨块组(B1)、后路C1-C2钉棒＋cage组(B2)。 利用Motion Analysis, co.6 Eagle系统对屈伸、侧屈、旋转方向运动范围（ROM）进行测量,并行统计学分析。  结果　相同固定方式组间比较,cage组比髂骨块组运动范围更小,屈伸方向稳定性依次为A2＞B2＞A1＞B1, 其中A1与A2比较, 有显著性差异（P=0.0125）, B1与B2比较, 有显著性差（P=0.0132）;相同置入物组间比较, 前路TARP与后路C1-C2钉棒固定力学稳定性无显著性差异(P>0.05)。  结论　寰枢椎融合术中使用cage比髂骨块具有更好的三维稳定性、理论上能够提高寰枢椎融合率,减少并发症。     

不同方式颈椎融合手术对上颈椎Jefferson骨折稳定效果的影响

目的建立人体上颈椎C0～3节段Jefferson骨折有限元模型,分析后路寰枢椎融合(posterior atlantoaxial fusion,PSF)和枕颈融合(occipitocervical fusion,OCF)对颈椎椎体生物力学特性和钉棒系统力传导特性的影响。方法基于CT图像建立人体上颈椎C0～3节段Jefferson骨折模型,依据临床手术方案实施PSF、OCF1和OCF2内固定术,施加50 N集中力和1.5 N·m力矩于枕骨底部,研究上颈椎C0～3节段在前屈、后伸、侧屈和旋转运动时,颈椎椎体的应力分布和关节活动度(range of motion,ROM)、钉棒系统最大应力以及椎间盘的应力分布情况。结果 OCF1和OCF2椎体ROM较PSF增加,钉棒应力减少,OCF具有较好的固定效果。结论 PSF、OCF1、OCF2固定术式均可减少上颈椎ROM,重建上颈椎的稳定性,使椎体和椎间盘应力分布趋向正常水平。研究结果可为临床手术方案提供理论依据。     

寰枢椎的解剖学测量及其临床意义

目的 :为寰枢椎区病损机制和手术治疗提供解剖学依据。方法 :在 15 0例中国成年人干燥寰枢椎标本上 ,对具有临床意义的数据进行解剖学测量。结果 :寰椎上关节面内倾角、下关节面外倾角及侧块内倾角两侧不对称分别占 19.3 %、10 .7%和 7.3 % ;椎动脉沟处形成沟环者占 16 .0 % ;所有横突孔的前后径和横径均大于 4mm ;后弓内侧半距仅为外侧半距的 1/2。枢椎椎弓根内倾角变异较大 (-3 .5°～2 1.5°) ;齿突腰部宽度小于 9mm者占 71.2 % ,齿突后倾角的变异较大 (0°～ 2 2°) ;2 7.5 %的椎动脉在经过枢椎侧块下方时会形成一动脉压迹沟 ,致使侧块外端和椎弓根变薄。结论 :①寰枢椎的解剖学形态与其生物力学性质及损伤机制密切相关 ;②手术时寰椎前弓向外显露不宜超过 2 0mm ,后弓切除向外不宜超过 10mm ,经寰枢外侧关节融合或内固定术应选择在关节的内侧 2 /3 ;③大部分中国人不适宜于两枚齿突螺钉内固定术 ;④ 2 7.5 %的中国人不适宜于经椎弓根螺钉固定术 ,枢椎椎弓根变异较大 ,手术前应作CT检测。     

掌骨重建钢板模拟单节段固定修复寰椎骨折:体外三维运动生物力学分析北大核心

背景:为了实现骨折复位的稳定以及尽量保留颈椎活动度的完整,国内外多学者均开展了有关单节段有限内固定的临床与实验研究,均取得了良好的临床疗效,未见明显的寰枢关节失稳而引起的不适症状。目的:采用体外三维运动法对掌骨重建钢板单节段固定不稳定性寰椎骨折进行生物力学分析。方法:使用新鲜上颈椎标本(C0-C5)6例,将标本造成寰椎前弓双骨折模型,并以掌骨重建钢板系统模拟进行单节段复位固定。测量每例标本的正常状态、骨折状态及内固定状态3组数据。比较骨折状态、内固定状态、正常状态的运动中性区及三维运动范围与正常状态的差异。结果与结论:(1)颈椎标本骨折状态与正常状态的运动中性区、三维运动范围差异均有显著性意义(P均<0.05);而内固定状态与正常状态的运动中性区、三维运动范围差异均无显著性意义(P均>0.05);(2)结果表明,掌骨重建钢板系统模拟单节段固定不稳定性寰椎骨折可以获得良好的稳定性,在恢复上颈椎稳定性的同时,可充分避免融合术的不良影响。     

Effects of the lesion of the postcommissural part of the septum on the behavior of the rat.

The effects of the lesion of the postcommissural part of the septum on behavior of the rat has been studied. Results may be summarized as follows. An increase in the exploratory behavior in the open field which decreases rapidly; a decrease in the number of defecations in this test and a decrease in time leaving a dark environment for exploration. In the shuttle box test, no facilitation of the acquisition, but a permanent and quite significant increase in the intertrial activity has been found. We conclude that the lesions tend to decrease the emotivity of the subjects. An interpretation on the basis of the species -- specific defensive reactions explains the transitory and permanent effects of the lesions on the spontaneous activity.     

Asymmetry of the internal connections of the striate cortex of the cat in the projection zone of the center of the field of vision

Studies were carried out on the organization of the internal connections of the striate cortex in cats in the projection zone of the center (0–5°) of the field of vision by microintophoretic application of horseradish peroxidase to electrophysiologically identified orientational columns. The area containing neurons showing retrograde labeling in most cases extended in the mediolateral direction. Labeled cells were located in the upper (II, III) and lower (V, VI) layers of the cortex, and the shapes and orientations of the areas containing labeled neurons in these layers coincided. Spatial asymmetry was detected in the distribution of labeled neurons relative to the orientational column studied. Labeled cells were located predominantly medial to the columns, regardless of the distance from the projection of the area centralis. Considering the visuotopical map of field 17, the asymmetry detected here provides evidence that neurons in orientational columns have more extensive connections with neurons of the peripheral part of the cortex. An asymmetrical distribution of “silent” zones around the receptive fields of neurons in orientational columns is suggested, and that these appear to receive influences from the periphery of the visual field. Laboratory of Visual Physiology and Laboratory of Central Nervous System Morphology, I. P. Pavlov Institute of Physiology, Russian Academy of Sciences, 6 Makarov Bank, 199034 St. Petersburg, Russia. Translated from Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 82, No. 12, pp. 23–29, December, 1996.     

Counterpointing the functional role of the forebrain and of the brainstem in the control of the sleep-waking system

This paper reviews the lifetime contributions of the author to the field of sleep-wakefulness (S-W), reinterprets results of the early studies, and suggests new conclusions and perspectives. Long-term cats with mesencephalic transection show behavioral/polygraphic rapid eye movement sleep (REMS), including the typical oculo-pupillary behavior, even when the section is performed in kittens prior to S-W maturation. REMS can be induced as a reflex. Typical non-rapid eye movement S (NREMS) is absent and full W/arousal is present only after a precollicular section. The isolated forebrain (IF) rostral to the transection exhibits all features of W/arousal and NREMS [with electroencephalographic (EEG) spindles and delta waves], arousal to olfactory stimuli, and including the appropriate oculo-pupillary behaviors. These features also mature normally after neonatal transection. REMS is absent from the IF. After deprivation there is NREMS pressure and rebound in the IF, but the decerebrate cat only shows pressure for REMS. Most IF reactions to pharmacologic agents are within expectations, except for the tolerance/withdrawal effects of long-term morphine use which are absent. In contrast, these effects are supported by the brainstem (i.e. seen in the decerebrate cat). In cats with ablation of the telencephalon, or diencephalic cats, delta waves are absent in the thalamus. EEG thalamic spindle waves are seen triggering S for only 4-5 days after ablation. Therefore, true NREMS is absent in chronic diencephalic cats although pre- and postsomniac behaviors persist. These animals are hyperactive and show a pronounced, permanent insomnia; however, a low dose of barbiturate triggers a dramatic REMS/atypical NREMS rebound. Cats without the thalamus (athalamic cats), initially show a dissociation between behavioral hyperactivity/insomnia and the neocortical EEG, which for 15-20 days exhibits only delta and slower oscillations. Fast, low-voltage W rhythms appear later on, first during REMS, but spindle waves and S postures are absent from the start, such that these cats also display only atypical NREMS. Athalamic cats also show barbiturate-sensitive insomnia. Cats with ablation of the frontal cortices or the caudate nuclei remain permanently hyperactive. They also show a mild, but significant hyposomnia, which is permanent in afrontal cats, but lasts for about a month in acaudates. The polygraphic/behavioral features of their S-W states remain normal. We conclude and propose that: (a) the control of the S-W system is highly complex and distributed, but is organized hierarchically in a well-defined rostro-caudal manner; the rostral-most or highest level (telencephalon), is the most functionally complex/adaptative and regulates the lower levels; the diencephalic/basal forebrain, or middle level, has a pivotal role in inducing switching between S and W and in coordinating the lowest (brainstem) and highest levels; (b) W can occur independently in both the forebrain and brainstem, but true NREMS- and REMS-generating mechanisms exist exclusively in the forebrain and brainstem, respectively; (c) forebrain and brainstem S-W processes can operate independently from each other and are preprogrammed at birth; this helps understanding normal and abnormal polygraphic/behavioral dissociations in humans and normal dissociations/splitting in aquatic mammals; (d) NREMS homeostasis is present in the IF, but only REMS pressure after deprivation persists in the decerebrate cat; (e) the thalamus engages in both NREMS and W; (f) insomnia in diencephalic cats is the result of an imbalance between antagonistic W- and S-promoting cellular groups in the ventral brain (normally modulated by the telencephalon); (g) the EEG waves, which are signature for each S-W state, appear to truly drive the concomitant behaviors, e.g. a hypothetical human IF could alternate between behavioral NREMS and W/arousal/awareness; (h) a role for REMS is to keep the individual sleeping at the end of the self-limiting NREMS periods. The need for accelerating research on telencephaling NREMS periods. The need for accelerating research on telencephalic S-W processes and downstream control of the lower S-W system levels is emphasized.     

The development of the ligament of the head of the femur

The hip joints of 30 human male and female fetuses and stillborns between 20 mm and 350 mm crown-rump length were studied by light microscopy. The ligament of the head of the femur developed in situ as a condensation of mesenchyme at the end of the second month of intra-uterine life (IUL), and was vascularized by branches of acetabular vessels early in the fourth month. In the majority of fetuses older than 5.5 months IUL, vessels in the ligament passed a short way into the femoral head within cartilage canals, to supply a small region around the fovea capitis. The remainder of the head was supplied by vessels in canals from around the upper part of the neck. The ligament changed from predominantly cellular to fibrous during the last 4 months of IUL. This increase in strength suggested significant mechanical functions in utero: limitation of adduction-flexion and opposition to postero-superior dislocation were the most likely.     

Ultrastructure of the endothelium of the drainage system of the eye

The endothelium of the ocular drainage system (Schlemm’s canal, collector tubules, and aqueous veins) in primary juvenile glaucoma undergoes degenerative dystrophic changes with compensatory hypertrophy and proliferation at the initial stages of the glaucomatous process and atrophy and desquamation at advanced and terminal stages. Progressive decrease in the pinocytous function of endotheliocytes, reduction of the protein-synthesizing and mitochondrial compartments of the cytoplasm, and formation of autophagosomes reflect the process of endotheliocyte degeneration in general. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 5, pp. 574–577, May, 2008     

Topical organization of the projections of neurons of the substantia nigra and the ventral field of the tegmentum of the midbrain to the head of the caudate nucleus of the cat

Neuroscience and Behavioral Physiology -     

Involvement of the striatum in the central regulation of the hormonal functions of the gonads

Studies reported here show that intrastriatal administration of corticoliberin to rats decreases the blood testosterone level. However, in conditions of chemical deficiency of dopaminergic transmission in the dorsal striatum induced by injection of 6-hydroxydopamine, the effect of this neurohormone did not appear. It is concluded that extrahypothalamic corticoliberin is involved in regulating the hormonal reproductive system acting via dopaminergic mechanisms. Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 85, No. 4, pp. 594–597, April, 1999.