颈椎终板的解剖及其生物力学特征的实验研究

目的：研究颈椎终板的解剖结构及其抗压强度。方法：应用直接法测量１０具新鲜成人尸体颈椎标本的终板厚度。标本切片进行光镜观察。生物力学测试比较保留终板和不保留终板时,其抗压强度及椎体植骨面的位移。结果：各节段颈椎终板和上、下终板之间的厚度差异均无显著性（Ｐ＞０．０５）,终板中央区为多孔的松质骨样结构,平均厚度为０．５１±０．０３ｍｍ。保留终板组与不保留终板组的抗压强度分别为１３６０．２±２５６．３Ｎ和８７７．１±１６７．３Ｎ,差异非常显著。其椎体植骨面位移分别为１．１４±０．５９ｍｍ和２．３５±０．７５ｍｍ,差异亦非常显著。结论：保留终板能显著增加颈椎椎体的抗压强度,减少椎体植骨面的位移     

颈椎牵引的生物力学研究

本文根据人体颈椎的生理解剖学特性，经生物力学分析建立了一个上端自由，下端固定的弹性曲杆颈椎模型。通过光弹性实验方法和应力分析的理论计算方法给出了颈椎牵引角与最大应力位置和颈椎生理曲线的关系。结果表明，牵引角度小时，最大应力位置靠近颈椎上段，随着牵引角度增大，最大应力位置逐渐下移。颈椎生理曲度改变时，牵引角度与最大应力位置的关系也相应改变。对２４０例颈椎病患者进行分组临床观察。一组按计算结果选择牵引角度，另一组以固定角度牵引，结果选择牵引角度组疗效明显优于固定角度牵引组。     

颈椎生物力学模型的应用及进展

生物力学模型是研究颈椎伤病的基础。通过对模型的观察、测试,可了解伤病的发生机理并提出诊治策略。因此生物力学模型的应用一直在颈椎伤病研究中占据重要地位。根据构成的特点和用途,Panjab[1]将其分为物理学模型,体外模型,体内模型和计算机模型。国内外文献对此有大量报道。现就近年来前三类模型的设计和应用及其进展进行综述,限于篇     

颈椎内固定生物力学研究进展

本文综述了近年来国外颈椎内固定方面的生物力学研究进展状况，包括实验检测标准化、检测方法、应力遮挡、实验模型、评价方法以及对各种内固定器材的评价等相关的各种尚未解决的问题。     

新型翼状颈椎间融合器植入颈椎即刻稳定性的生物力学评价

用三维有限元法测试自行设计的翼状颈椎间融合器(ACIFC)的生物力学性能,探讨其用于颈椎椎间前路融合的可行性。在有限元分析软件ABAQUS中模拟植入ACIFC的颈椎前路椎体融合术,进行术后即刻稳定性的生物力学分析。计算出活动度(ROM),分析其力学性能,并与相关实验数据进行了比较性分析。椎间融合器植入后,颈椎活动度下降了25%,与植入前有显著性差异(P<0.05)。同时,ACIFC有较好的抗拔出性能和具备较好的植骨融合环境。可以证实ACIFC能为颈椎椎间融合提供足够的初始生物力学稳定性。     

颈椎前路钮扣钢板的研制及生物力学评价

目的:研制颈椎前路钮扣钢板内固定系统,评价其生物力学稳定性。方法:用317L不锈钢研制出颈椎前路钮扣钢板螺钉系统。取6具青年男性新鲜尸体的颈椎标本,制成5种状态脊柱功能单位(FSU)的试验模型:正常颈椎、屈曲型损伤、单纯植骨、钮扣钢板内固定、AO钢板内固定。利用脊柱三维运动分析系统测定不同状态下颈椎节段的运动范围(ROM),比较钮扣钢板内固定与AO钢板内固定对失稳颈椎的稳定作用,并摄X线片观察各种状态下颈椎的影像学改变。结果:生物力学测试表明,钮扣钢板内固定系统可以对失稳颈椎提供明显的稳定作用(P<0.01),与AO钢板内固定系统的稳定作用相比无显著性差异(P>0.05)。动态X线摄片显示,钮扣钢板内固定及AO钢板内固定均能维持植骨块的稳定,并恢复椎间隙高度及颈椎生理曲度,而单纯植骨则容易出现植骨块的移位、凸出甚至脱出。结论:钮扣钢板内固定系统具有较好的生物力学稳定性。操作简便,适合国人颈椎解剖结构及功能特点。     

两种动力性颈椎前路钢板对颈椎稳定性的生物力学比较

目的：比较Codman和Window两种动力性颈椎前路钢板对颈椎单椎间减压植骨融合模型稳定性，为临床提供理论依据。方法：将12例小牛颈椎标本随机分成两组。用生物力学测定仪测定正常颈椎C4.5节段在前屈、后伸、左右侧屈、左右旋转时的三维运动范围（ROM），然后切除C4/5椎间盘，制成损伤模型，测定植骨加钢板，植骨块缩短1mm加钢板固定后C4/5节段的ROM，植骨块的长度根据测量椎间隙的高度而定。结果：Codman和Window两种钢板加植骨时的ROM在屈／伸、侧屈、旋转时相似，无显著性差异（P〉0．05），其中在屈／伸时的ROM与正常标本相比小，有显著性差异（P〈0．05），在侧屈时、旋转时与正常标本相比无显著性差异（P〉0．05）；在植骨缩短后，两种钢板的ROM均不同程度的变大。其中Codman组在屈／伸、侧屈、旋转时与正常标本相比无显著性差异（P〉0．05），Window组在屈／伸时与比正常标本无显著性差异（P〉0．05），但在侧屈、旋转时大，有显著性差异（P〈0．05）。结论：Codman钢板在植骨与植骨块缩短后均能对颈椎提供有效的稳定性，Window钢板在植骨时能提供有效的稳定性，但在植骨缩短后不能对颈椎提供有效的颈椎稳定性。     

颈椎斜扳手法的生物力学实验研究

推拿临床上颈椎斜板法操作常带有一定盲目性，使用不当可能会导致严重的医源性损伤。本实验采用七具新鲜颈椎标本，运用生物力学电测技术，设计了一种斜扳装置，测量了斜扳时颈椎寰齿关节和关节突关节在不同生理，病理状态；拔伸与非拔伸条件下的关节作用内力变化。结果显示：正常生理状态下斜板，后伸位的局部作用力大于前屈位和中立位，前屈位关节内力最小；颈椎病理失稳下斜板，关节内力显著增大，而拔伸下斜扳能有效降低关节内力     

终板凹陷角变化对腰椎运动节段生物力学影响的有限元分析

目的:研究终板凹陷程度变化对腰椎运动节段生物力学影响。方法:在以往建立的腰椎L4～5运动节段三维非线性有限元模型基础上,采用CAD方法精确构建三种不同终板凹陷角改变的有限元模型,有限元模型的椎间盘前凸角、小关节间隙等其余形态学参数及网格划分均保持一致。垂直压缩、屈曲、伸直、前后剪力5种载荷条件下,分别对三种有限元模型生物力学参数进行测试。结果:负载条件下,终板凹陷角增加、终板凹陷程度减小可导致终板-椎间盘界面应变减小,椎间盘刚度及髓核内压增加,椎间盘膨出、纤维环纤维张应力、纤维环基质应力、腰椎后部结构应力以及关节突接触力减小。结论:终板凹陷程度的减小增强了椎间盘对椎体的保护作用;同时可通过影响终板的形变减少对椎间盘的营养传递。     

甲状旁腺素和二膦酸盐对骨密度和骨生物力学的影响

目的:研究应用甲状旁腺素和阿仑膦酸钠对激素性骨质疏松兔骨密度和生物力学的影响。方法:采用成年新西兰大白兔,随机分为对照组、激素模型组、甲状旁腺素和阿仑膦酸钠治疗组,9周后取股骨和腰椎行超声骨密度测量,再行股骨扭转、三点弯曲和腰椎压缩试验。结果:激素模型组的宽频超声衰减(BUA)、超声传导速度(SOS)值和骨生物力学参数较对照组有非常明显减少,甲状旁腺素和阿仑膦酸钠治疗组的BUA、SOS值和骨生物力学参数较激素模型组明显增加。结论:序贯应用甲状旁腺素和阿仑膦酸钠可以减少激素性兔骨量的丢失,预防骨质疏松的发生。     

Relationship between blood pressure levels and bone mineral density in postmenopausal Turkish women

Introduction

We investigated the association between bone mineral density (BMD) detected by dual-energy X-ray absorptiometric (DXA) method and blood pressure (BP) in a large sample of postmenopausal women.

Material and methods

The current study was based on a retrospective analysis of 586 postmenopausal women with a mean age of 60.8 ±8.8 years, who were screened for osteopenia or osteoporosis by DXA. Patients with hypertension (HT, n= 306) were compared with normotensive (NT, n = 290) individuals. Bone mineral density results for the femur neck and spine were classified into 3 groups according to World Health Organization criteria: normal (T score > –1.0 SD), osteopenia (T score –1.0 to –2.5 SD) and osteoporosis (T score < –2.5 SD). Patients with osteopenia or osteoporosis (T score < –1.0 SD) were grouped as having low bone mass (LBM).

Results

There were no significant differences in femur T score, femur BMD, femur Z score, spinal T score, spinal BMD and spinal Z score between hypertensive and normotensive groups. The group of patients with low bone mass calculated from femur T scores had higher age, systolic BP, duration of hypertension and duration of menopause, but lower BMI. Similarly, patients with low spine BMD had higher age and duration of menopause, but lower BMI. Linear regression analysis showed a significant correlation between systolic BP and femur BMD and T score values. Furthermore, logistic regression analysis revealed that hypertension is an independent predictor of spinal osteopenia and osteoporosis.

Conclusions

The presence of hypertension is an independent predictor of spinal low bone density in Turkish women after menopause.     

终板蛋白多糖的变化对颈椎间盘力学性能的影响

目的:通过测定退变颈椎间盘压缩性能的改变,同时观测软骨终板基质蛋白多糖(proteoglycan PG)的变化,为退变的椎间盘显现异常力学特性作一分子机制上的探讨。方法:将24只家兔随机分为对照组和模型组,模型组家兔保持45°低屈曲住5小时/次·天,取C5-6椎间盘进行生物力学测定;同时生化测定椎间盘终板糖胺多糖(glycosaminoglycan,GAG)总量、硫酸软骨素(chongdroitin sulphate,CS)和硫酸角质素(keratan sulphate,KS)比值和透明质酸(hyaluronic acid,HA)含量;总结分析颈椎间盘退变时基质各成分的系统变化及其对椎间盘力学性能的影响。结果:模型组终板抗压强度、断裂时的最大形变、终板基质蛋白多糖总含量、硫酸软骨素/硫酸角质素比值、透明质酸含量都低于对照组(P<0.05),并随造模进程的深入而减小。结论:长时间的应力不均状态,造成椎间盘终板材料力学特性改变;颈椎间盘基质蛋白多糖含量和成分改变是颈椎间盘生物力学性能减退的主要原因之一。     

体脂对DXA骨密度测量结果及骨质疏松诊断的影响

随着社会老龄化和生活水平提高,制约老年人健康长寿的骨质疏松症受到越来越多的重视。双能Ｘ线吸收测量法(dual energy X-ray absorptiometer,DXA)测量骨密度是诊断骨质疏松的金标准,但它的精确性受身体脂肪含量的影响。体脂可以干扰DXA测量骨密度的结果,这可能会导致体脂分布改变显著者（如绝经后体脂分布变化较大的女性）骨质疏松诊断的偏倚,造成此类人群骨质疏松时误诊或漏诊的发生。本文就脂肪对骨密度测量结果及骨质疏松诊断的影响作一综述。     

人体松质骨矿质密度与弹性模量关系

目的 测量人体多部位松质骨矿质密度、轴向弹性模量,建立矿质密度与轴向弹性模量相关关系的本构方程,为国人有限元材料属性赋值提供依据。方法 采取10例成人新鲜尸体作为样本源,选取胫骨近端、大转子、股骨颈、肱骨头和椎体5个部位的松质骨,加工成直径约6 mm、长约30或40 mm的准试样。测量尺寸并计算体积,CT扫描试样骨矿质密度。对松质骨试样进行力学性能测试,分析不同部位松质骨弹性模量。对矿质密度与轴向弹性模量关系进行线性与幂次回归分析。结果 测试成功的试样来自5个部位,共169枚,其中胫骨近端52枚,大转子31枚,股骨颈15枚,肱骨头17枚,椎体54枚;5个部位松质骨矿质密度、轴向弹性模量均有所差异,线性相关性均较好（0.850>r2>0.785）,3个部位（胫骨近端、大转子、椎体）的幂次相关性较好（0.871>r2>0.825）,2个部位（肱骨头、股骨颈）的幂次相关性较弱(0.671>r2>0.643)。结论 各个部位骨矿质密度与轴向弹性模量的线性和幂次回归的相关性均较高,且同部位两种回归的r2值之间无明显差异;可应用于体外检测患者的骨骼质量,准确分辨骨质变化的部位,配合有限元建模能够预测骨折的风险。     

Relation between obesity and bone mineral density and vertebral fractures in Korean postmenopausal women

Purpose

The traditional belief that obesity is protective against osteoporosis has been questioned. Recent epidemiologic studies show that body fat itself may be a risk factor for osteoporosis and bone fractures. Accumulating evidence suggests that metabolic syndrome and the individual components of metabolic syndrome such as hypertension, increased triglycerides, and reduced high-density lipoprotein cholesterol are also risk factors for low bone mineral density. Using a cross sectional study design, we evaluated the associations between obesity or metabolic syndrome and bone mineral density (BMD) or vertebral fracture.

Materials and Methods

A total of 907 postmenopausal healthy female subjects, aged 60-79 years, were recruited from woman hospitals in Seoul, South Korea. BMD, vetebral fracture, bone markers, and body composition including body weight, body mass index (BMI), percentage body fat, and waist circumference were measured.

Results

After adjusting for age, smoking status, alcohol consumption, total calcium intake, and total energy intake, waist circumference was negatively related to BMD of all sites (lumbar BMD p = 0.037, all sites of femur BMD p < 0.001) whereas body weight was still positively related to BMD of all sites (p < 0.001). Percentage body fat and waist circumference were much higher in the fracture group than the non-fracture group (p = 0.0383, 0.082 respectively). Serum glucose levels were postively correlated to lumbar BMD (p = 0.016), femoral neck BMD (p = 0.0335), and femoral trochanter BMD (p = 0.0082). Serum high density lipoprotein cholesterol (HDLC) was positively related to femoral trochanter BMD (p = 0.0366) and was lower in the control group than the fracture group (p = 0.011).

Conclusion

In contrast to the effect favorable body weight on bone mineral density, high percentage body fat and waist circumference are related to low BMD and a vertebral fracture. Some components of metabolic syndrome were related to BMD and a vertebral fracture.     

Ovariectomy-associated changes in bone mineral density and bone marrow haematopoiesis in rats

The relationship between the bone mass loss and bone marrow haematopoiesis in osteoporosis remains obscure. We selected 3-month-old female Sprague–Dawley rats and randomly divided them into six groups. Three groups were ovariectomized (OVX), while the other three groups were sham operated (Sham). Four, 8 and 12 weeks after the surgical procedure, the rats were euthanized and sampled. The left femur was used for measurement of bone mineral density (BMD). The right femur distal metaphysic cancellous bone was processed for morphological evaluation. Our results showed that the femur BMD in the 4-week OVX group was not significantly decreased compared with that of the 4-week Sham group, but that the volume of adipose tissue in the bone marrow was markedly increased. The femur BMD in the 8-week OVX group was decreased significantly compared with that of the 8-week Sham group ( P   <   0.05). Meanwhile, the volume of haematopoietic tissue decreased and the volume of adipose tissue increased. The number of megakaryocytes was decreased ( P   <   0.05). Interestingly, the osteoclasts and mast cells were increased in number in the 8-week OVX group ( P   <   0.05). These changes became obvious in the 12-week OVX rats, in contrast to the Sham groups. The volume of trabecular bone and the number of osteoblasts in the 12-week OVX group decreased significantly. Increased reticulin fibres were observed only in the 12-week OVX group. Our studies demonstrated a reciprocal correlation between bone-forming osteoblasts and marrow adipose tissue and suggest that OVX rats may be valuable as an animal model to study hypohaemopoiesis.     

辛伐他汀和吉非罗齐对高脂血症伴骨量减少患者骨代谢和骨密度的影响

目的观察辛伐他汀和吉非罗齐对高胆固醇血症伴骨量减少患者骨代谢指标及骨密度的影响。方法高脂血症合并骨量减少患者128例,分两组后分别予以辛伐他汀和吉非罗齐治疗,并在治疗前及治疗后分别检测血脂、骨吸收标志物血清I型胶原羧基末端肽（sCTX）、骨形成标志物总骨Ⅰ型前胶原N端肽（P1NP）和桡骨远端骨密度（BMD）。结果辛伐他汀组平均治疗周期（10.24±1.89）个月,治疗后总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白（LDL-C）明显降低（P〈0.05）,同时sCTX降低（P〈0.01）,P1NP增高（P〈0.05）,BMD增加（P〈0.01）,而吉非罗齐治疗后虽TC、TG、LDL-C明显降低（P〈0.05）但sCTX、P1NP和BMD无明显变化。结论较大剂量辛伐他汀具有抑制骨吸收、增强骨形成和增加BMD的作用,可能与血脂水平降低无关。