青年与老年人脊柱黄韧带黏弹性实验研究

目的比较青年与老年人脊柱黄韧带的应力松弛和蠕变黏弹性力学性质,为黄韧带退变的黏弹性力学机制提供依据。方法 20例老年腰椎退变病人黄韧带标本为老年退变组,20例青年腰椎外伤病人黄韧带为青年组,黄韧带标本均取自L4～L5间黄韧带。以1%/s的应变增加速度和0.5 MPa/s的应力增加速度分别对试样进行应力松弛和蠕变实验,实验温度设定为(36.5±0.5)℃。设定试验时间为7 200 s,采集90个应力松弛和蠕变数据。以统计分析和归一化的方法处理实验数据。结果青年组黄韧带7 200 s应力下降了1.42 MPa,老年组黄韧带7 200 s应力下降了1.91 MPa。青年组黄韧带7 200 s应变上升了3.39%,老年组黄韧带7 200 s应变上升了2.07%,两组7 200 s应力均下降,应变上升数据均有统计学意义(P<0.05)。应力松弛曲线是以对数关系变化的,蠕变曲线是以指数关系变化的。结论老年退变组黄韧带和青年组黄韧带相比,7 200 s应力松弛量和蠕变量降低,黏弹性力学性能发生改变。     

骨性关节炎动物模型内侧副韧带的应力松弛

背景：韧带和其他生物软组织一样,具有黏弹性特性,其应力松弛和蠕变黏弹性特性是为适应人的生理功能需要而存在的。研究说明骨性关节炎对韧带力学性能具有一定影响。 目的：比较正常和骨性关节炎动物模型内侧副韧带的应力松弛流变特性,确定骨性关节炎对内侧副韧带应力松弛特性的影响。 方法：以闭合关节刻痕法复制骨性关节炎动物模型,取正常和骨性关节炎动物模型大鼠膝关节内侧副韧带各10个试样,进行应力松弛实验。应力松弛实验的应变增加速度为5%/s。设定实验时间为7 200 s,采集100个数据,观察应力松弛数据和曲线、应力与时间的变化规律,以一元线性回归分析的方法处理实验数据。 结果与结论：正常组和病态组试样应力松弛最初600 s变化较快,之后应力缓慢下降,正常组7 200 s应力松弛量0.47 MPa,病态组7 200 s应力松弛量0.29 MPa。模型组7 200 s应力松弛量显著低于正常组(P < 0.05),且应力松弛曲线是以对数关系变化的。说明骨性关节炎时可以使膝关节对内侧副韧带应力松弛量降低,对膝关节应力松弛特性具有一定影响。     

骨性关节炎动物模型外侧副韧带应力松弛特性的研究

比较正常和骨性关节炎动物模型外侧副韧带的应力松弛流变特性,确定骨性关节炎对外侧副韧带应力松弛特性的影响.在日本岛津电子万能试验机上对正常和病态各8个试样进行应力松驰实验.应力松弛实验的应变增加速度为5%/s.设定实验时间为7 200 s,采集100个数,以一元线性回归分析的方法处理实验数据.结果表明:正常和病态组试样应力松弛最初600 s变化较快,之后应力缓慢下降,正常组7 200 s应力松弛量为2.231 Mpa,病态组7 200 s应力松弛量为2.458 Mpa.表明应力松弛曲线是以对数关系变化的,骨性关节炎对外侧副韧带应力松弛特性具有一定影响.     

正常与病态股骨头应力松弛特性的对比分析

比较正常股骨头和股骨头坏死后股骨头应力松弛性质,为人工关节研究和髋关节置换术提供应力松弛参数。在日本岛津电子万能试验机上对正常与病态股骨头各8个试样进行应力松弛实验。模拟人体温在36.5℃的温度场下进行实验,以5%/s的应变增加速度对标本施加应变,设定时间为7 200 s,采集100个实验数据。采用三参数模型计算应力松弛方程。观察应力松弛曲线和7 200 s应力松弛量。股骨头在最初600 s变化较快,之后应力缓慢下降,正常组7 200 s应力松弛量为0.31 MPa,病态组7 200 s应力松弛量为0.22 MPa,病态组7 200 s应力松弛量显著低于正常组(P<0.05)。股骨头坏死后打乱了松质骨头骨小梁的正常排列,骨量丢失,从而对应力松弛特性造成影响。应力松弛数据可以定量地说明坏死股骨头应力松弛特性差。     

正常与病态股骨头应力松弛特性的对比分析

比较正常股骨头和股骨头坏死后股骨头应力松弛性质,为人工关节研究和髋关节置换术提供应力松弛参数。在日本岛津电子万能试验机上对正常与病态股骨头各8个试样进行应力松弛实验。模拟人体温在36.5℃的温度场下进行实验,以5%/s的应变增加速度对标本施加应变,设定时间为7 200 s,采集100个实验数据。采用三参数模型计算应力松弛方程。观察应力松弛曲线和7 200 s应力松弛量。股骨头在最初600 s变化较快,之后应力缓慢下降,正常组7 200 s应力松弛量为0.31 MPa,病态组7 200 s应力松弛量为0.22 MPa,病态组7 200 s应力松弛量显著低于正常组(P<0.05)。股骨头坏死后打乱了松质骨头骨小梁的正常排列,骨量丢失,从而对应力松弛特性造成影响。应力松弛数据可以定量地说明坏死股骨头应力松弛特性差。     

膝关节前交叉韧带与后交叉韧带粘弹性实验研究

研究了10具新鲜成人尸体膝关节前交叉韧带和后交叉韧带的拉伸力学性质和粘弹性力学性质,对前交叉韧带和后交叉韧带进行单向拉伸实验,得出了破坏载荷,强度极限、最大应变、伸长比、弹性模量.对前交叉韧带和后交叉韧带进行应力松弛,蠕变实验,得出了应力松弛、蠕变实验数据和曲线.对实验数据进行归一化处理,得出了归一化应力松弛函数,蠕变函数,以回归分析的方法处理实验数据,得出了回归系数,很好的拟合了实验曲线.实验结果表明:前交叉韧带的拉伸强度极限、最大应变等大于后交叉韧带,后交叉韧带7200s应力松弛、蠕变量小于前交叉韧带.     

前交叉韧带粘弹性特性的实验研究

目的 探讨前交叉韧带的力学性能和粘弹性行为与时间的变化规律，为研究人工韧带提供生物力学参数。方法 对正常国人新鲜尸体膝关节前交叉韧带进行系统的拉伸、应力松驰、蠕变实验，得出最大载荷、强度极限、最大应变、弹性模量等；还得出了应力松驰、蠕变实验数据和曲线，归一化应力松驰函数、蠕变函数数据和曲线。并得到7200s时的蠕变量和应力松驰量。结果 ①前交叉韧带在实验中表现出典型的松弛、蠕变现象，说明其粘弹性性质在膝关节运动中起着重要的缓冲作用。②最初600s时应力应变的变化幅度较大，之后应力缓慢下降，应变缓慢上升，前交叉韧带7200s时应力松弛量1．05Mp，蠕变量为6．82％。结论 前交叉韧带具有良好的粘弹性力学性质。其粘弹性力学行为是为了适应其所在解剖部位的功能需要。     

膝关节前交叉韧带与内侧副韧带粘弹性实验研究

目的　研究了新鲜成人尸体膝关节前交叉韧带和内侧副韧带的粘弹性力学性质，为临床提供生物力学参数依据。方法　对前交叉韧带和内侧副韧带进行应力松弛，蠕变实验。结果　对实验数据进行归一化处理，得出了归一化应力松弛函数，蠕变函数，以回归分析的方法处理实验数据，得出了回归系数和拟合曲线。结论　内侧副韧带7200s应力松弛、蠕变量小于前交叉韧带。对实验结果进行分析讨论。     

髂股韧带与股骨头韧带黏弹性实验研究

目的 研究新鲜成人尸体髋关节髂股韧带和股骨头韧带的黏弹性力学性质,为临床提供生物力学参数.方法 取正常国人髂股韧带和股骨头韧带各10个试样进行应力松弛、蠕变实验.结果 得出了应力松弛、蠕变实验曲线,以回归分析的方法处理实验数据,得出了回归系数.结论 髂股韧带7200s应力松弛蠕变量显著大于股骨头韧带.     

股骨下端松质骨横向与纵向应力松弛特性

背景：以往的研究多以一个标本加工成二个或多个试样进行实验,且标本多以纵向取样进行应力松弛实验。 目的：比较股骨下端松质骨横向和纵向取样的拉伸应力松弛特性,为临床提供股骨下端松质骨的生物力学参数。 方法：正常国人男性尸体股骨标本10个,左右侧各5个,年龄20~30岁,死亡后1 h内解剖尸体取出左、右侧股骨,以生理盐水浸湿的沙布包裹标本,置于-20 ℃冰箱内保存。实验前取出标本,在常温下解冻,每个标本加工成长20 mm,宽     20 mm,高20 mm的试样。先对10个试样进行纵向应力松弛实验,之后待试样恢复24 h后再对10个标本进行横向应力松弛实验。应力松弛实验的应变增加速度为0.5%/s,设定实验时间为7 200 s,采集100个实验数据。 结果与结论：股骨下端松质骨纵向试样7 200 s应力松弛量为0.58 MPa,横向试样7 200 s应力松弛量为0.72 MPa。应力松弛曲线是以对数关系变化的。股骨下端松质骨横向7 200 s应力松弛量大于纵向。结果可以看出三参数模型建立的股骨下端松质骨的应力松弛方程能很好的反映股骨下端松质骨的应力松弛特性。     

The Lumbar Ligamentum Flavum Does Not Have Two Layers and Is Confluent with the Interspinous Ligament: Anatomical Study with Application to Surgical and Interventional Pain Procedures

Numerous authors over the years have reported that the lumbar ligamentum flavum has two layers. Our routine cadaveric dissections raised the question whether this understanding is correct, as we always have observed only one layer. Thus, the goal of this cadaveric study was to reevaluate the layers of the ligamentum flavum. Twenty lumbar levels from five fresh-frozen cadaveric specimens were used in this study. After dissection of the lumbar spine, the ligamentum flavum and interspinous ligament were exposed. Each lumbar level was transected through the zygapophyseal joint, and hematoxylin and eosin staining, Masson's trichrome staining and Verhoeff-van Gieson staining were performed. Continuation of the interspinous ligament and ligamentum flavum were observed invariably. There was no evidence of the existence of a two-layered ligamentum flavum. The lumbar ligamentum flavum does not consist of two layers, but is confluent instead with the interspinous ligament that attaches to the zygapophyseal joints. To convey this anatomy better, we suggest describing the lumbar ligamentum flavum as a structure that consists of interlaminar and interspinous parts. Precise knowledge of the ligamentum flavum's anatomy can be of clinical value, particularly when epidural anesthesia or lumbar puncture are performed. Clin. Anat. 32:34–40, 2019. © 2019 Wiley Periodicals, Inc.     

Viscoelastic properties of the cervical spinal ligaments under fast strain-rate deformations

The mechanical response of ligaments under fast strain-rate deformations is a necessary input into computational models that are used for injury assessment. However, this information frequently is not available for the ligaments that are routinely injured in fast-rate loading scenarios. In the current study, experiments were conducted at fast strain rates for the cervical spinal ligaments: the anterior longitudinal ligament, the posterior longitudinal ligament and the ligamentum flavum. Bone-ligament-bone complexes at three spine levels were harvested for mechanical testing. Displacement-controlled sub-failure uniaxial tensile tests were performed in both load-relaxation and sinusoidal conditions. A nonlinear (separable) viscoelastic model was used to examine the experimental data. An unexpected result of the modeling was that the instantaneous elastic functions could be approximated as linear for these strain rates. A five-parameter model was sufficient to characterize the ligament viscoelastic responses and had good predictive capacity under different applied loading conditions.     

Validation of a C2–C7 cervical spine finite element model using specimen-specific flexibility data

This study presents a specimen-specific C2–C7 cervical spine finite element model that was developed using multiblock meshing techniques. The model was validated using in-house experimental flexibility data obtained from the cadaveric specimen used for mesh development. The C2–C7 specimen was subjected to pure continuous moments up to ±1.0 N m in flexion, extension, lateral bending, and axial rotation, and the motions at each level were obtained. Additionally, the specimen was divided into C2–C3, C4–C5, and C6–C7 functional spinal units (FSUs) which were tested in the intact state as well as after sequential removal of the interspinous, ligamentum flavum, and capsular ligaments. The finite element model was initially assigned baseline material properties based on the literature, but was calibrated using the experimental motion data which was obtained in-house, while utlizing the ranges of material property values as reported in the literature. The calibrated model provided good agreement with the nonlinear experimental loading curves, and can be used to further study the response of the cervical spine to various biomechanical investigations.     

后方韧带复合体逐级切除对损伤胸腰椎稳定性的影响

目的研究后方韧带复合体逐级切除对损伤胸腰椎稳定性的影响,验证棘上韧带对维持损伤胸腰椎稳定的作用。方法取8具健康新鲜人体T11~L3节段标本,于L1椎体中1/3行楔形切除,并在材料试验机上压缩至闭合以制备L1椎体骨折。对T12~L1处后方韧带复合体按照关节囊、棘间韧带、棘上韧带、黄韧带的顺序进行逐级切除,依次连续测量T12~L1节段前屈、后伸、侧弯、旋转运动时的运动范围(range of motion,ROM)及中性区(neutral zone,NZ)变化。结果在前屈和后伸运动中,椎体切除及棘上韧带断裂后,ROM及NZ显著增加。在侧弯运动中,椎体切除和关节囊破坏后,ROM显著增加。在旋转活动中,椎体切除及关节囊破坏导致ROM增加,NZ无显著增加。结论棘上韧带断裂后,T12~L1节段稳定性发生显著下降,尤其在前屈运动中。棘上韧带是维持胸腰椎节段稳定性的关键韧带。     

后方韧带复合体逐级切除对损伤胸腰椎稳定性的影响

目的 研究后方韧带复合体逐级切除对损伤胸腰椎稳定性的影响,验证棘上韧带对维持损伤胸腰椎稳定的作用。方法 取8具健康新鲜人体T11~L3节段标本,于L1椎体中1/3行楔形切除,并在材料试验机上压缩至闭合以制备L1椎体骨折。对T12~L1处后方韧带复合体按照关节囊、棘间韧带、棘上韧带、黄韧带的顺序进行逐级切除,依次连续测量T12~L1节段前屈、后伸、侧弯、旋转运动时的运动范围（range of motion, ROM）及中性区（neutral zone, NZ）变化。结果 在前屈和后伸运动中,椎体切除及棘上韧带断裂后,ROM及NZ显著增加。在侧弯运动中,椎体切除和关节囊破坏后,ROM显著增加。在旋转活动中,椎体切除及关节囊破坏导致ROM增加,NZ无显著增加。结论 棘上韧带断裂后,T12~L1节段稳定性发生显著下降,尤其在前屈运动中。棘上韧带是维持胸腰椎节段稳定性的关键韧带。     

后方韧带复合体逐级切除对损伤胸腰椎稳定性的影响

目的 研究后方韧带复合体逐级切除对损伤胸腰椎稳定性的影响,验证棘上韧带对维持损伤胸腰椎稳定的作用。方法 取8具健康新鲜人体T11~L3节段标本,于L1椎体中1/3行楔形切除,并在材料试验机上压缩至闭合以制备L1椎体骨折。对T12~L1处后方韧带复合体按照关节囊、棘间韧带、棘上韧带、黄韧带的顺序进行逐级切除,依次连续测量T12~L1节段前屈、后伸、侧弯、旋转运动时的运动范围（range of motion, ROM）及中性区（neutral zone, NZ）变化。结果 在前屈和后伸运动中,椎体切除及棘上韧带断裂后,ROM及NZ显著增加。在侧弯运动中,椎体切除和关节囊破坏后,ROM显著增加。在旋转活动中,椎体切除及关节囊破坏导致ROM增加,NZ无显著增加。结论 棘上韧带断裂后,T12~L1节段稳定性发生显著下降,尤其在前屈运动中。棘上韧带是维持胸腰椎节段稳定性的关键韧带。     

Spinal balance failure: a potential cause of spinal ligament ossification

Ossification of the posterior longitudinal ligament (OPLL) and of the ligamentum flavum (OLF), as well as calcification of ligamentum nuchae in the cervical spine and ossification of ligamentum flavum in the thoracic spine, are common types of spinal ligament ossification. As is known, the pathogenesis of OPLL and OLF has been unclear until recently, and mechanical stress assumably plays an important role. In this paper, we try to make a hypothesis that spinal balance failure (characterized by the gravity line, spinal curvature and flexion/extension in the sagittal plane), may play more important roles than any other factors in the development of ligament ossified diseases. Moreover, different stress thresholds and flexion/extension frequency may induce various ossification regions. It is supported by the conclusions that drawn from literature review: (1) OPLL and OLF seldom occur in lumbar spine which is of stiffer and lower-frequency motion than cervical spine, although its range of motion (ROM) was relatively great. (2) Spinal ligament ossification often appears in the cervical spine, which is significantly flexible with a larger motion range. (3) OLF is often seen in the thoracic spine, which is farthest away from the gravity line for thoracic kyphosis. (4) Many OPLL or OLF patients are often found with a local kyphosis or high segmental ROM. (5) The prevalence of ossification is higher in the larger stress regions, as described above, indicating that there may be a stress threshold for the spinal ligaments.     

Numerical Simulation of Asymmetrically Altered Growth as Initiation Mechanism of Scoliosis

The causes of idiopathic scoliosis are still uncertain; buckling is mentioned often, but never proven. The authors hypothesize another option: unilateral postponement of growth of MM Rotatores or of ligamentum flavum and intertransverse ligament. In this paper, both buckling and the two new theories of scoliotic initiation are studied using a new finite element model that simulates the mechanical behavior of the human spine. This model was validated by the stiffness data of Panjabi et al. (J. Biomech. 9:185–192, 1976). After a small correction of the prestrain of some ligaments and the MM Rotatores the model appeared to be valid. The postponement in growth was translated in the numerical model in an asymmetrical stiffness. The spine was loaded axially and the resulting deformation was analyzed for the presence of the coupling of lateral deviation and axial rotation that is characteristic for scoliosis. Only unilateral postponement of growth of ligamentum flavum and intertransverse ligament appeared to initiate scoliosis. Buckling did not initiate scoliosis.