Shape variation of the neural arch in the thoracic and lumbar spine: characterization and relationship with the vertebral body shape

Quantifying the human vertebral geometry is important for accurate medical procedures. We aimed to characterize the neural arch (NA) shape at T1-L5. All T1-L5 dry vertebrae (N = 4,080) of 240 individuals were measured and analyzed by age, gender, and ethnicity. A 3D digitizer was used to measure the dimensions of the spinous (SP) and transverse (TP) processes, vertebral canal (VC), laminae, and isthmus. Most parameters were independent of age and ethnicity, yet greater in males than in females. Isthmus length increases from T1 (9.8 mm) to T12 (19.87 mm) and decreases from T12 to L5 (9.68 mm) with right > left in the thorax and oppositely in the lumbar region. The SP is longer than its thickness both decreasing in the upper thorax (by ca. 4mm), increasing in the lower thoracic and upper lumbar vertebrae (by 7 mm for length and ca. 14.5 mm for thickness) and decreasing again along the lower lumbar vertebrae (both by 8 mm). The TP length decreases at T1-T12 (by 13 mm) and increases at L1-L5 with left > right at T1-L5 (P < 0.003). The laminar length decreases from T1 (8.72 mm) through T5 (4.76 mm) and increases toward L5 (8.4 mm) with right > left at T1-L5 (P < 0.003). The VC is oval-shaped at T1 and T11-L5 (width > length), rounded-shape at T2 and T10 (width = length), and inverted oval-shaped at T3-T9 (length > width). In conclusion, the NA is systematically asymmetrical and dynamic in shape along the thoracic and lumbar spine. The inter-relationship with the vertebral body and articular facets is discussed.     

腰5峡部裂合并不同椎间节段退行变与髂腰韧带的关系

目的：探讨第5腰椎峡部裂合并不同椎间节段退行变与髂腰韧带的相关性。方法：分析L5峡部裂患者的临床资料，随机抽取病例分为两组：16例合并L4-5椎间盘突出、16例合并L5滑脱，对照比较两组病例间的L5横突的相对宽度（RT值）。结果：L5峡部裂合并L4-5椎间盘突出组比合并L5滑脱组的RT值高，两者差别有统计学意义。结论：L5峡部裂合并L4-5椎间盘突出的髂腰韧带强度比合并L5脊椎滑脱高。L5峡部裂合并不同节段椎间盘突出或合并滑脱的病因可能除了与峡部裂引起脊椎失稳及椎间盘退变有关外，还与髂腰韧带力学强度有关。     

Vertebral body shape variation in the thoracic and lumbar spine: characterization of its asymmetry and wedging

This study was designed to characterize the vertebral body (VB) shape, focusing on vertebral wedging, along the thoracic and lumbar spine, and to look for shape variations with relation to gender, age, and ethnicity. All thoracic and lumbar (T1-L5) dissected vertebrae of 240 individuals were measured and analyzed by age, gender, and ethnicity. A 3D digitizer was used to measure all VB lengths, heights, and widths, and their ratios were calculated. This study showed that the VB size was independent of age or ethnicity. VB left lateral wedging was found in most vertebrae of most individuals, yet systematically was absent in six vertebrae (T4, T8-T9, T11, L3-L4) with a greater tendency in females than males ( approximately 92% vs. 86%). The VB was anteriorly wedged from T1 through L2 (peak at T7), nonwedged at L3, and posteriorly wedged at L4-L5 (peak at L5). VB width decreased from T1 to T4 and then increased toward L4-L5, so that the spinal configuration in the coronal plane resembled two pyramids of opposite directions, sharing an apex at T4. The inferior VB width was significantly greater than the superior width of both the same vertebra and the adjacent lower vertebra, indicating a trapezoidal shape of the VB and an inverted trapezoidal shape of the intervertebral space. In conclusion, these findings indicate that the human vertebra, in its normal condition, maintains its external dimensions with age, independent of gender or ethnic origin. Clinical and surgical implications of the unique thoracolumbar architecture are discussed.     

Quantitative anatomy of vertebral artery groove on the posterior arch of atlas in relation to spinal surgical procedures

Background The location of the vertebral artery on a groove on the superior surface of the posterior arch of atlas makes it vulnerable to injury during surgical procedures in this region. Knowledge of the quantitative anatomy of the vertebral artery groove is therefore necessary. Methods In 55 dry adult atlas vertebrae, the distance of the medial edges of the vertebral artery groove were measured from the posterior midline at both the inner and outer cortices of the posterior arch of atlas. In addition, the distance between the vertebral artery grooves on either side as well as the length of the vertebral artery groove was also measured. Results It was found that a minimum of 1.5 cm of the posterior arch could be safely exposed at both the outer and inner cortices. In addition, with mobilization of the vertebral artery from its groove on both the sides, an additional 1 cm of posterior arch could be exposed on either side. Conclusions Exposure of the posterior arch of the atlas is an important step in surgical procedures for treatment of diverse conditions of the upper spinal cord and foramen magnum region. Injury to the vertebral artery in its position on the vertebral groove may lead to disastrous complications. The present study reveals that the neurosurgeon can safely expose up to 3.5 cm of the posterior arch of atlas and knowledge of this anatomic fact may help in planning surgical approaches.     

正常人腰椎椎体解剖结构的QCT研究及其生物力学意义

采用一系列ＣＴ技术对正常人第一腰椎体结构进行研究。根据皮骨的厚度和骨质特点可分为三个区，松质骨具有高度的不均匀性，三维重建提示皮质骨呈薄壳样结构，松质骨呈三维“工”的相对致密结构，支撑于终板间。作者认为：①皮质骨的薄壳结构具有承重和分散应力的作用；②松质骨的三维“工”结构有利于均匀承载来自终板的压应力；③椎体中部位于向心性凹陷的皮质骨和轴心致密皮质骨间的横行骨小梁对椎体轴向承重具有动力性强化作用；④皮质骨形成的封闭腔室可加强多孔材料的硬化效应。尚分析了椎体结构的薄弱点，提出椎体破坏的结构根据。具有无创、三维和定量特点的ＣＴ是椎体结构研究的有利手段。     

腰椎椎体应力分布的三维有限元分析

应用三维有限元方法对腰椎椎体应力分布的研究表明.椎体松质骨的应力集中区域位于邻近终板的中央部分,而椎间盘发生退变后这一现象即不明显.作者认为椎体的应力分布及腰椎的载荷传递依据椎间盘的情况而不同,并对有关的临床意义进行了讨论.     

胸腰椎椎弓根的解剖学测量及其临床意义

目的　观测胸腰椎椎弓根形态结构特征 ,为临床提供解剖学参数。方法　测量 31例成年男性椎骨T1～L5的横径、矢径、椎弓根间距及椎弓根通道长度。结果　横径 :T1～T6逐渐变小 ,T6～T12 逐渐增大 ,L1和L2 小于T12 ,L2 ～L5逐渐增大 ;矢径 :T1～T3 逐渐增大 ,T4～T7均小于T3 和T8,T7～T12 又逐渐增大 ,L1～L3 逐渐变小 ,L3 ～L5又逐渐增大 ,T1～L5均明显大于其横径 (P <0 0 1) ;模仿弓根通道长 :T1～T10 逐渐增长 ,T11和T12 均较T10 和L1短 ,L1～L4逐渐增长 ,L5较L4短 ;椎弓根间距 :T1～T4逐渐变窄 ,T5～L5逐渐增宽 ;左右侧比较无显著性差异 (P >0 0 5 )。结论　进行椎弓根螺钉固定时应根据不同节段椎弓根形态特点 ,结合影像学资料 ,选择相应的螺钉直径、长度、进钉部位及方向。     

Ligaments of the lumbar neural foramina: A sectional anatomic study

The ligaments of the lumbar neural foramina have not been systematically described. We sectioned the lumbar spines of 15 cadavers in the sagittal plane with a cryomicrotome and identified the ligaments in the neural foramina. Fibrous ligaments were identified in every lumbar neural foramen. The most constant ligament was a band of fibrous tissue behind the anulus fibrosus and distinct from it, originating in one vertebral body and inserting in the next. Ligaments connecting the posterior disc margin and the superior articular process were found in 48% of the neural foramina. A band of fibrous tissue originating from the anulus fibrosus and inserting along the pedicle and superior articular process was found in 44% of the foramina. Three other distinct types of ligament were found less commonly. Ligaments, which some investigators believe may contribute to lateral spinal stenosis, are commonly present in the neural foramina.     

Developmental morphology of the cervical vertebrae and the emergence of sexual dimorphism in size and shape: A computed tomography study

Cervical vertebral bodies undergo substantial morphological development during the first two decades of life that are used clinically to visually determine skeletal maturation with the cervical vertebral maturation index (CVMI). CVMI defines six stages that capture the morphological transformations from 6 years to 18 years. However, CVMI has poor reproducibility given its qualitative nature and does not account for sexual dimorphism. This study aims to quantify the morphological development of the cervical vertebral bodies C2–C7 in size (height and depth) and shape and examine the emergence of sexual dimorphism. Using 115 (70 M;45F) computed tomography studies from typically developing individuals ages 6 months to 20 years, landmarks were placed at the margins of the C2–C7 cervical vertebral bodies in the midsagittal plane for size and shape analysis. Findings revealed a dichotomy in the growth trends of height versus depth. The C2–C7 growth in depth gained the majority of the adult size by age 5 years, while the C3–C7 growth in height displayed two periods of accelerated growth during early childhood and puberty. Significant sex differences were found in height and depth growth trends and the form-space ontogenetic trajectories during puberty, with minor but evident differences emerging at age 3 years. Female C2–C7 depth measures were smaller than males at all ages. However, sex differences in height became evident due to males continuing to grow after females reach maturity. Findings quantify the morphological developmental stages of CVMI and emphasize the need to account for sex differences when assessing skeletal maturation.     

胸椎上关节突基底外1/3点为椎弓根进钉点的应用解剖

目的:研究胸椎上关节突基底外1/3点与椎弓根的解剖关系,为胸椎椎弓根穿钉提供一种新的定位方法。方法:选取45具成人干燥骨标本(男25具,女20具),测量胸椎上关节突基底外1/3点至相应椎弓根上缘、下缘、中轴线垂直距离,至内缘、外缘、中轴线水平距离,最适内倾角度、最适尾倾角度、最大内倾角度、最大尾倾角度。据测量结果设置穿钉参数,在5具尸体上模拟穿钉,CT评价螺钉位置。结果:各组长度、角度之性差比较无显著统计学意义(P>0.05)。胸椎上关节突基底外1/3点在椎弓根上缘、下缘、内缘、外缘所成框内,与椎弓根中轴线接近;最适内倾角度T1￣T3为25°,T4￣T10为15°,最适尾倾角度10°,据此参数在5具尸体上模拟穿钉均获成功。结论:胸椎上关节突基底外1/3点作胸椎椎弓根穿钉定位点,具有准确、可靠、简单实用等优点,是一良好的解剖定位标志。     

Effect of soft tissue thickness over the posterior border of the vertebral body and disc space on cage placement during posterior lumbar interbody fusion: A cadaveric study

In the present study, we investigated whether there is a difference between visual depth (VD) and radiological image depth (RD) of cages (i.e., structural interbody support devices) placed in disc spaces during posterior lumbar interbody fusion and whether soft tissues covering the posterior border of the vertebral body and associated disc space are the cause of any observed differences. Using digital calipers, cages were inserted at a depth of 5 mm from the soft tissues covering the posterior border of the vertebral body and disc space under direct vision; this depth was defined as VD. After insertion, RD was measured in triplicate. The reliability of RD measurements was evaluated using an intraclass coefficient test. To identify the cause of differences between VD and RD, the thicknesses of soft tissues were measured microscopically. A total of 40 lumbar intervertebral disc spaces with cages were evaluated. The mean RD of cages was 3.12 mm, while the mean difference between the VD and RD of cages (DVRD) was 1.91 mm. On histological examination, the mean thickness of the soft tissue was 2.02 mm. Comparative analysis between histological values and DVRD showed no statistical difference (P = 1.14, 1.55, 0.06). There was a significant difference between VD and RD during cage placement, and soft tissue structure appeared to be responsible for the DVRD of inserted cages. Therefore, cages should be inserted deeper to account for differences between visual and radiological image depths. Clin. Anat. 25:1066–1073, 2012. © 2012 Wiley Periodicals, Inc.     

正常成年人椎体氢质子磁共振波谱与个体因素的初步研究

目的应用氢质子磁共振波谱(1H-MRS)技术,探讨正常成年人腰椎(L1~L4)椎体的脂水比(LWR)和脂肪含量(FF%)与性别、年龄及体质量指数(BMI)之间的关系。方法选择100例MRI检查正常的成年人,其中男性52例(52%),女性48例(48%);年龄18~79岁,平均年龄46.77岁;平均BMI为22.85。按性别、年龄及BMI进行分组:男性组52例,女性组48例:青年组(≤44岁)44例,中年组(45~59岁)33例,老年组(≥60岁)22例;正常组(18.5BMI24.0)69例,超质量肥胖组(BMI≥24)31例。所有纳入对象行MRI常规扫描及L1~L4椎体的1H-MRS扫描,测量并记录椎体的LWR及FF%,采用SPSS13.0对所有数据按组别进行统计学分析。结果 L1~L4椎体的平均LWR及FF%分别为1.20±0.75、1.41±0.93、1.57±1.05、1.58±1.09和0.50±0.15、0.53±0.15、0.56±0.15、0.56±0.15,LWR及FF%在性别及年龄组间的差异具有统计学意义(P0.05),而BMI组间差异不具有统计学意义(P0.05);相关性分析结果显示,L1~L4椎体的LWR和FF%与年龄呈正相关(P0.05,相关系数为0.47~0.54),但与BMI没有相关性(P0.05)。结论 L1~L4各椎体的LWR和FF%均存在性别差异(男性高于女性),并随着年龄的增加而增大。     

颈椎钩突邻近结构薄层断面与MRI对照研究

目的阐明颈椎钩突在薄层断面和MRI断面图像上与周围结构的毗邻关系,为颈椎退行性疾病提供影像学诊断依据。方法选取5例中国数字化可视人体（CVH）数据集中C3-C7椎体上缘清楚显示钩突的薄层断面图像,观察并测量钩突与邻近的椎动脉和颈神经的位置关系,选择对应平面的MRI断面图像对照分析。结果CVH数据集的薄层断面清晰显示颈椎钩突及其周围结构,在断面上测量并得出钩突与颈神经、钩突与椎动脉的距离的平均值,MRI清楚显示颈椎钩突及其邻近结构。结论将CVH数据集中的颈椎钩突平面的薄层断面与对应的MRI图像进行对照研究,可为颈椎病的影像学诊断和治疗提供形态学参考。     

椎弓根进钉点间距及最佳内倾进钉角的CT测量及其在术中的应用

目的 :研究确定胸腰椎同一椎体的椎弓根进钉点间距离及其相关的最佳内倾进钉角 (最佳TSA) ,为手术操作提供一准确的数据。方法 :利用术前进钉椎体的椎弓根中部的CT检查 ,测定椎弓根进钉点间距及最佳TSA。结果 :利用该方法协助术中椎弓根螺钉的进钉操作 ,提高了椎弓根钉安装的质量及成功率。结论∶利用术前CT测定的椎弓根进钉点间距及确定最佳TSA协助术中椎弓根定位及进钉方向 ,是一种简单可靠的方法。     

Cervical vertebral body growth and emergence of sexual dimorphism: a developmental study using computed tomography

The size and shape of human cervical vertebral bodies serve as a reference for measurement or treatment planning in multiple disciplines. It is therefore necessary to understand thoroughly the developmental changes in the cervical vertebrae in relation to the changing biomechanical demands on the neck during the first two decades of life. To delineate sex‐specific changes in human cervical vertebral bodies, 23 landmarks were placed in the midsagittal plane to define the boundaries of C2 to C7 in 123 (73 M; 50 F) computed tomography scans from individuals, ages 6 months to 19 years. Size was calculated as the geometric area, from which sex‐specific growth trend, rate, and type for each vertebral body were determined, as well as length measures of local deformation‐based morphometry vectors from the centroid to each landmark. Additionally, for each of the four pubertal‐staged age cohorts, sex‐specific vertebral body wireframes were superimposed using generalized Procrustes analysis to determine sex‐specific changes in form (size and shape) and shape alone. Our findings reveal that C2 was unique in achieving more of its adult size by 5 years, particularly in females. In contrast, C3–C7 had a second period of accelerated growth during puberty. The vertebrae of males and females were significantly different in size, particularly after puberty, when males had larger cervical vertebral bodies. Male growth outpaced female growth around age 10 years and persisted until around age 19–20 years, whereas females completed growth earlier, around age 17–18 years. The greatest shape differences between males and females occurred during puberty. Both sexes had similar growth in the superoinferior height, but males also displayed more growth in anteroposterior depth. Such prominent sex differences in size, shape, and form are likely the result of differences in growth rate and growth duration. Female vertebrae are thus not simply smaller versions of the male vertebrae. Additional research is needed to further quantify growth and help improve age‐ and sex‐specific guidance in clinical practice.     

The torg ratio of C3–C7 in African Americans and European Americans: A skeletal study

The ratio between the sagittal diameter of the spinal canal and the sagittal diameter of the vertebral body, known as the “Torg ratio”, is often used to test for spinal canal narrowing. Here, we investigate this ratio in a large population, consisting of two ethnicities, both sexes and three age groups. Measurements were taken on the dry cervical verterbrae (C3–C7) of 277 individuals using a digital apparatus allowing for the recording of 3D coordinates of a set of landmarks on the vertebral body. Vertebral body and vertebral foramen lengths were compared across the different subgroups. Vertebral body and vertebral foramen lengths differ significantly between males and females and between African Americans and European Americans. With age, the vertebral body length increases while the foramen length does not undergo significant changes. These anatomical differences are reflected in differences in the Torg ratio calculated for the different subgroups. In conclusion, our findings suggest that a hard cutoff on the Torg ratio used to define a pathological narrowing of the cervical spine should be adapted to the population the patients come from. Clin. Anat. 32: 84‐89, 2019. © 2018 Wiley Periodicals, Inc.     

A model of the human lumbar vertebral column: a preliminary study

Summary Finite element modelling of the human lumbar vertebral column employs data-processing procedures for study of the linear and nonlinear elasticity of materials such as are currently used in mechanics or in civil engineering. Thanks to developments in computer science, requiring a close collaboration between doctors and engineers, we put forward in this preliminary study a linear computerised model of the lumbar column comprising 4824 meshes and 6813 nodes. By reducing the simplificatory hypotheses and integrating new parameters, this model as developed is capable of important clinical applications in surgery and ergonomics.

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Modélisation de la colonne lombaire humaine. Etude préliminaire

Résumé La modélisation en éléments finis de la colonne lombaire humaine utilise les procédés informatisés d'étude de l'élasticité linéaire et non linéaire des matériaux telle qu'elle est couramment employée en mécanique ou en génie civil. Grâce au développement de l'informatique, nécessitant une collaboration étroite entre médecins et ingénieurs, nous proposons, dans cette étude préliminaire, un modèle informatisé linéaire de la colonne lombaire comportant 4824 mailles et 6813 noeuds. En réduisant les hypothèses simplificatrices et en intégrant de nouveaux paramètres, ce modèle évolué est susceptible d'importantes applications cliniques en chirurgie et en ergonomie.

     

新型3D打印多孔钛人工椎体在猪脊柱模型置换前后的生物力学测试研究

目的通过对新型3D打印多孔钛人工椎体在猪脊柱模型置换前后的生物力学测试比较研究,评价该新型3D打印人工椎体的活动范围情况和即刻的生物力学稳定性。方法选取18具新鲜相近的猪脊柱标本(L1-L6),根据L3椎体置换前后,分为置换前组和置换后组。分别测试前屈、后伸、左右侧屈、左右旋转的位移角度变化。结果在0~8N.m逐级加载中,置换后组运动节段在前屈、后伸、左右侧屈各向量的位移角度变化明显小于置换前组,差异有统计学意义(0.05),而在轴位旋转位上,两者无显著性差异(0.05)。结论新型3D打印人工椎体的设计具有合理性和创新性,在猪脊柱模型L3椎体置换后,即刻可获得良好的生物力学稳定性。     

Influence of age and gender on thoracic vertebral body shape and disc degeneration: an MR investigation of 169 cases

There are limited data detailing the pattern of age and gender-related changes to the thoracic vertebral bodies and intervertebral discs. A retrospective MR investigation, involving T1-weighted midsagittal images from 169 cases, was undertaken to examine age influences on the anterior wedge (anteroposterior height ratio or Ha/Hp), biconcavity (midposterior height ratio or Hm/Hp), and compression indices (posterior height/anteroposterior diameter or Hp/D) of the thoracic vertebral bodies. Disc degenerative changes in the annulus, nucleus, end-plate and disc margin were noted on T2-weighted sagittal images for the 169 cases, based on a 3-level grading system. A linear age-related decline in the Ha/Hp and Hm/Hp indices was noted. The Hp/D index increased during the first few decades of life, then decreased gradually thereafter. The prevalence of abnormal findings in the annuli, nuclei and disc margins increased with increasing age, particularly in the mid and lower thoracic discs. Greater disc degenerative changes were observed in males. These findings provide further insight into the nature of thoracic vertebral shape changes across the lifespan, and the typical patterns of degeneration of the thoracic intervertebral discs.     

植入不同直径椎弓根螺钉后腰椎体与椎弓根结合部位骨折力学的稳定性

文题释义：腰椎体与椎弓根结合部位骨折：此为腰椎弓根骨折中的一种类型,腰椎弓根骨折还包括椎弓根体部骨折、椎弓根与椎板结合部位骨折,而腰椎体与椎弓根结合部位骨折较椎弓根体部骨折更为稳定,多数学者主张此型骨折可以经伤侧椎弓根植入椎弓根螺钉。 三维有限元：该方法是目前力学仿真的主要方法之一,通过获取人体的CT或MRI数据,建立逼真的三维模型,再通过将模型网格化,赋予网格相应的材料属性,然后再进行力学分析。因为该方法是获取人体数据后建模,较动物实验更能有效模拟人体结构发生变化时的力学变化。 背景：多数学者认为腰椎与椎弓根结合部位骨折较为稳定,可经由伤侧椎弓根植入椎弓根螺钉来提高骨折断端的稳定性,但经伤侧椎弓根植入的椎弓根螺钉直径大小与椎弓根、椎体所获得的力学稳定性、安全性目前尚有争议。 目的：利用三维有限元法分析不同直径椎弓根螺钉植入椎弓根内与椎弓根皮质关系对骨折腰椎与椎弓根力学稳定性的影响。 方法：基于正常成人L₂-L₃ CT DICOM数据,通过mimics软件建立L₂椎体一侧腰椎体与椎弓根结合部位骨折模型,同时建立L₃椎体三维模型。将制作好的L₂-L₃模型以stl格式导入3-matic中,建立经L₂椎体与椎弓根结合部位骨折处植入不同直径椎弓根螺钉(椎弓根螺钉直径分别为6.5,6.0 mm,长度均为45 mm)的模型,将上述模型在mimics软件中赋予材料属性后导入ansys中,在L₂椎体上表面施加500 N的垂直载荷,模拟标准体质量成人经伤椎植入不同直径螺钉后直立情况下的生物力学表现。 结果与结论：①植入6.0 mm螺钉后,腰椎体与椎弓根结合部位椎弓根下壁、上壁、内壁、外壁所承受的等效载荷分别为(1.28±0.62),(0.95±0.18),(0.62±0.37),(0.36±0.16)MPa,4组间比较差异有显著性意义(F=4.298,P < 0.05);②植入6.5 mm螺钉后,腰椎体与椎弓根结合部位椎弓根下壁、上壁、内壁、外壁所承受的等效载荷分别为(1.82±0.76),(1.11±0.18),(0.93±0.38),(0.43±0.14)MPa,4组间比较差异有显著性意义(F=7.034,P < 0.05);③植入6.5 mm椎弓根螺钉模型椎弓根下壁、上壁、内壁、外壁所承受的等效载荷均大于植入6.0 mm椎弓根螺钉模型对应处(P < 0.05);④结果表明,椎弓根螺钉越大对腰椎体与椎弓根结合部位皮质骨的压力载荷越大,把持力越强;椎弓根上壁、下壁、内壁、外壁所承受的载荷与其皮质厚度呈正相关,下壁皮质骨最厚,其承受的等效载荷最大,外侧壁皮质骨最薄,其承受的等效载荷最小;椎弓根螺钉在椎弓根内越靠近下内侧壁,其把持力越强、稳定性越好,越靠近上外侧壁其把持力越小、稳定性越差,但上外侧壁较下内侧壁置钉更为安全,置钉时仍需依据手术医师的经验权衡利弊进行。 ORCID: 0000-0003-0823-4728(宗治国) 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