The vertebral level of origin of spinal nerves in the rat

Several dissections were performed to determine the level of spinal cord termination and the vertebral level at which the dorsal and ventral roots of spinal nerves C1-S4 emerged from the spinal cord in the rat. These levels of emergence were then compared to the level of exit from the vertebral canal. The dissections demonstrated that the effect of differential growth between spinal cord and vertebral column begins in the lower cervical region and becomes progressively more pronounced throughout thoracic and lumbar levels. The disparity between the vertebral level of emergence of spinal roots from the spinal cord and their level of exit via intervertebral foramina was found to be considerably larger than was previously reported by Greene ('68). It was further noted that the spinal cord terminated at the level of the intervertebral disc between the third and fourth lumbar vertebrae, not between the fourth and fifth lumbar vertebrae as reported by Greene ('68).     

Progressive vertebral fusion of unknown etiology: a case report

We report a 16-year-old male with progressive vertebral fusion of the cervical, thoracic, and lumbar vertebrae; irregular vertebral body surfaces; coronal clefting of the vertebral bodies of the thoracic and lumbar spine; absence of one cervical vertebra; and a few other minor, nonspinous abnormalities. All laboratory findings have been within normal limits. To our knowledge, the particular findings in this patient have not been reported previously.     

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。     

The human lumbar anterior epidural space: morphological comparison in adult and fetal specimens

To increase our understanding of the clinical anatomy of the epidural space, the human lumbar anterior epidural space was studied morphologically and developmentally. Histological transverse sections of human lumbar spines were taken at the level of the intervertebral disc and the vertebral body in adult specimens and in fetuses aged 13, 15, 21, 32 and 39 weeks (menstrual age). At 13 weeks, connective tissue filled the epidural space. The dura mater was attached anteriorly to the posterior longitudinal ligament (PLL). The PLL was attached to the vertebral body beside the midline, whereas it adhered to the posterior edge of intervertebral disc. The anterior internal vertebral venous plexus was located anterolaterally and anteromedially. The vertebral canal was lined with connective tissue that differentiated in a periosteum in contact with the ossification centers. At 15 weeks, the PLL was composed of deep and superficial layers. At 21 weeks, the attachment between the dura mater and PLL was ligament-like at the level of the vertebral body. At 32 weeks, the dura mater was adherent to the superficial layer of PLL. At 39 weeks, groups of adipocytes were identified, and the dura mater was attached to the PLL by some ligaments. There were many more similarities between the adult and the 39-week fetus. In conclusion, some differences in the anatomy of the epidural space exist at each fetal stage studied. The structures of the epidural space are already formed in the fetus of 13 weeks, but they differentiate progressively within the connective tissue.     

Biomechanical analysis of the lumbar spine with anterior interbody fusion on the different locations of the bone grafts

The anterior lumbar interbody fusion is the common procedure in the management of the degenerated disc in the lumbar spine, but the biomechanical behavior of the fused segment would be changed because of the implantation of bone graft at the different locations. To investigate the biomechanical alteration, the study applied the finite element model to undergo the stress analysis.A three-dimensional finite element model of the lumbar spine was established, and modified to the three fusion models consisted of the bone graft at the anterior site, the middle site and the posterior site, respectively. The 12 N m flexion and the 10 N m torsion with pre-load 150 N were imposed on the L1 vertebral body.The results of the finite element model indicated that placing bone graft at anterior site could effectively resist flexion moment, and decreased the tensile force of the posterior ligaments about 15% above. Placing bone graft at posterior site could resist torsional moment, and also led to none of contact force of the facet joint in the fused segment. However, wherever the bone grafts were placed, stress slightly increased on the disc adjacent to interbody fusion about 5% below.     

脊柱跟随载荷在离体生物力学应用研究中的进展

阐述跟随载荷在维持脊柱生物力学中的重要性,归纳近年来人离体脊柱标本跟随载荷模拟的各种方法及手段。通过与人体脊柱各椎体活动度、椎间盘内压等真实数据对比,从力学角度分析各类模拟手段的可行性,总结人体颈椎、胸椎、腰椎离体生物力学实验中最适合的加载载荷及扭矩,并探讨常规脊柱内固定术式对脊柱生物力学特性的影响。     

Geometry of the Intervertebral Volume and Vertebral Endplates of the Human Spine

Replacement of a degenerated vertebral disc with an artificial intervertebral disc (AID) is currently possible, but poses problems, mainly in the force distribution through the vertebral column. Data on the intervertebral disc space geometry will provide a better fit of the prosthesis to the vertebrae, but current literature on vertebral disc geometry is very scarce or not suitable. In this study, existing CT-scans of 77 patients were analyzed to measure the intervertebral disc and vertebral endplate geometry of the lumbar spine. Ten adjacent points on both sides of the vertebrae (S1-superior to T12-inferior) and sagittal and transverse diameters were measured to describe the shape of the caudal and cranial vertebral planes of the vertebrae. It was found that the largest endplate depth is located in the middle or posterior regions of the vertebra, that there is a linear relationship between all inferior endplate depths and the endplate location (p < 0.0001) within the spinal column, and that the superior endplate depth increases with age by about 0.01 mm per year (p < 0.02). The wedge angle increases from T12-L1 to L5-S1. The results allow for improvement of the fit of intervertebral disc-prostheses to the vertebrae and optimized force transmission through the vertebral column.     

显微内窥镜下手术治疗腰椎椎体后缘离断症

目的探讨腰椎椎体后缘离断症的有效手术方法。方法 2004年3月~2009年9月采用显微内窥镜手术治疗腰椎椎体后缘离断症26例,将其分为侧方型及中央型。侧方型22例,其中离断骨块位于L4椎体后下缘2例,L5椎体后上缘8例,S1椎体后上缘12例,均合并同侧椎间盘突出。中央型4例,离断骨块均位于S1椎体后上缘中央。侧方型采用单侧入路,按照扩大神经根管,摘除突出椎间盘髓核及椎体后缘离断骨块顺序进行手术;中央型采用双侧入路,扩大神经根管及中央椎管,摘除突出椎间盘髓核及椎体后缘骨块。结果所有患者随访19~84个月,平均42.5个月,按照Macnab术后评定标准:优20例,良6例。结论显微内窥镜手术治疗腰椎椎体后缘离断症具有创伤小,对腰椎后结构破坏少的优点,可有效摘除椎体后缘骨块及突出椎间盘,降低术后发生腰椎不稳的可能。     

下腰椎骨性结构参数与腰椎间盘突出症的关系

背景：腰椎各骨性结构参数的变化是下腰部脊柱骨性结构的形态改变的直接反应,这种改变很可能是在长期受到外在或内在因素影响后脊柱正常结构应变的结果,但不同参数反映的情况是否相同以及与对应的临床症状是否有相关性尚待探讨。 目的：测量和比较下腰椎间盘突出症患者的腰椎骨性结构参数,分析参数变化与下腰椎间盘突出症的相关关系。探讨腰椎骨性结构的异常是否为腰椎间盘突出症的病因,以及在腰椎间盘退行性变中的意义。 方法：纳入2008年3月至2010年3月解放军南京军区福州总院第一附属医院骨科收治的腰椎间盘突出症患者207例,同期于放射科行CT检查显示非腰椎间盘突出者143例作为对照组。按性别差异分为男、女组;按年龄分为25-34岁组、35-44岁组、45-54岁组、55-65岁组。测量的腰椎骨性结构参数包括棘突偏斜角、关节突关节角、腰椎曲度、腰椎曲度角、腰骶关节角。 结果与结论：腰椎间盘突出症组与对照组的棘突偏斜角在L4、L5水平存在差异,数据不呈正态分布,应用秩和检验,Z值为-10.609,-12.074,P < 0.01。腰椎间盘突出症组与对照组的关节突非对称性、腰椎生理曲度、腰椎曲度角、腰骶关节角在各年龄组及总体比较差异无显著性意义(P > 0.05)。从性别上看,男、女组仅在腰骶关节角上差异有显著性意义(P=0.007 < 0.01);各年龄段间比较,55-65岁组关节突非对称性、腰椎生理曲度、腰椎曲度角、腰骶关节角分别与25-34岁组、35-44岁组之间比较差异有显著性意义(P < 0.01),在45-54岁组和25-34岁组之间差异有显著性意义(P < 0.01)。提示腰椎骨性结构参数的变异不是直接导致腰椎间盘突出症的发病原因,但腰椎骨性结构参数的异常在腰椎间盘退行性改变中的作用是不可否认的。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：     

Finite element modeling of the cervical spine: role of intervertebral disc under axial and eccentric loads

An anatomically accurate, three-dimensional, nonlinear finite element model of the human cervical spine was developed using computed tomography images and cryomicrotome sections. The detailed model included the cortical bone, cancellous core, endplate, lamina, pedicle, transverse processes and spinous processes of the vertebrae; the annulus fibrosus and nucleus pulposus of the intervertebral discs; the uncovertebral joints; the articular cartilage, the synovial fluid and synovial membrane of the facet joints; and the anterior and posterior longitudinal ligaments, interspinous ligaments, capsular ligaments and ligamentum flavum. The finite element model was validated with experimental results: force–displacement and localized strain responses of the vertebral body and lateral masses under pure compression, and varying eccentric anterior-compression and posterior-compression loading modes. This experimentally validated finite element model was used to study the biomechanics of the cervical spine intervertebral disc by quantifying the internal axial and shear forces resisted by the ventral, middle, and dorsal regions of the disc under the above axial and eccentric loading modes. Results indicated that higher axial forces (compared to shear forces) were transmitted through different regions of the disc under all loading modes. While the ventral region of the disc resisted higher variations in axial force, the dorsal region transmitted higher shear forces under all loading modes. These findings may offer an insight to better understand the biomechanical role of the human cervical spine intervertebral disc.     

Radiographic and Magnetic Resonance Imaging Identification of Thoracolumbar Spine Variants with Implications for the Positioning of the Conus Medullaris in Rhesus Macaques

The anatomy of the vertebral column in mammals may differ between species and between subjects of the same species, especially with regards to the composition of the thoracolumbar spine. We investigated, using several noninvasive imaging techniques, the thoracolumbar spine of a total of 44 adult rhesus macaques of both genders. Radiographic examination of the vertebral column showed a predominant spine phenotype with 12 rib‐bearing thoracic vertebrae and 7 lumbar vertebrae without ribs in 82% of subjects, whereas a subset of subjects demonstrated 13 rib‐bearing thoracic vertebrae and 6 lumbar vertebrae without ribs. Computer tomography studies of the thoraco‐lumbar spine in two cases with a pair of supernumerary ribs showed facet joints between the most caudal pair of ribs and the associated vertebra, supporting a thoracic phenotype. Magnetic resonance imaging (MRI) studies were used to determine the relationship between the lumbosacral spinal cord and the vertebral column. The length of the conus medullaris portion of the spinal cord was 1.5 ± 0.3 vertebral units, and its rostral and caudal positions in the spinal canal were at 2.0 ± 0.3 and 3.6 ± 0.4 vertebral units below the thoracolumbar junction, respectively (n = 44). The presence of a set of supernumerary ribs did not affect the length or craniocaudal position of the conus medullaris, and subjects with13 rib‐bearing vertebrae may from a functional or spine surgical perspective be considered as exhibiting12 thoracic vertebrae and an L1 vertebra with ribs. Anat Rec, 300:300–308, 2017. © 2016 Wiley Periodicals, Inc.     

New dysostosis showing multilevel absence of vertebral pedicles: unique developmental anomaly of vertebral arches?

We report on an apparently normal child who shows hypopaplasia of the vertebral pedicles and posterior arches of several cervical, thoracic, and lumbar vertebrae with normally fused spinous apophyses, hypoplastic sacrum, lumbar epidural lipomatosis, synostoses of some cervical vertebral disks, and sacral spina bifida. The most likely mechanism is an abnormal differentiation of the spinal processes, due most probably to an absence of differentiation in cartilage of the dense mesenchyme forming their most anterior part. Because the anomalies affect multiple levels, we highly suspect a genetic basis to this unusual dysostosis affecting the development of the posterior sclerotomes.     

Segmental patterns of sagittal spinal curvatures in children screened for scoliosis: Kyphotic angulation at the thoracolumbar region and the mortice joint

This paper reports a segmental analysis of the lateral spinal radiographs of 37 children referred to hospital in a school screening study of 4,890 school children aged 12–13 years. On each lateral radiograph a line was drawn along the posterior surface of each vertebral body from T5-L5 and the angle of this line from the vertical was recorded. After measuring the scoliosis curve (Cobb) angle and using conventional criteria for diagnosis, three groups of patients are defined, namely, 1) a control group (average scoliosis curve angle (Cobb) of 5°, n = 14), 2) a group with lumbar curves (average Cobb angle 21°, n = 7), and 3) a group with thoracic curves (average Cobb angle 19 degrees, n = 10). Individual lateral spinal profiles are also analyzed. The findings show: (1) In the control group, there are different degrees of vertical backward tilt (declivity) from T7–L3, with a maximum tilt at T12 (mean 26°). The most vertical vertebrae are T6 and L4, with forward tilting (proclivity) at each of (T5 and L5.2) In the lumbar curve group, the segmental sagittal tilt is not significantly different from that in the control group. The mean declivity at T12 is 25°. (3) In the thoracic curve group, the segmental sagittal tilt is significantly less than that in the control group at each of T10–L1. The mean declivity at T12 is 17°. A more vertical T12 is associated with a larger Cobb angle. (4) The individual sagittal spinal profiles of the thoracic curve group (but no other group) show lordosis in the region of the lateral spinal curve (scoliosis) and a kyphotic angulation at an average of three vertebrae below the apical vertebrae of the scoliosis curve. (5) It is suggested that as a thoracic lordoscoliosis develops, the appearance of a kyphotic angulation in the thoracolumbar and upper lumbar spine is determined by the compressibility of each disc in relation to the length of the articular processes at the corresponding level. Where the combination of disc weakness to facet length is most adverse, forward flexion occurs, as in a spinal fracture, to produce the kyphotic angulation. © 1992 Wiley-Liss, Inc.     

The cat vertebral column: stance configuration and range of motion

This study examined the configuration of the vertebral column of the cat during independent stance and in various flexed positions. The range of motion in the sagittal plane is similar across most thoracic and lumbar joints, with the exception of a lesser range at the transition region from thoracic-type to lumbar-type vertebrae. The upper thoracic column exhibits most of its range in dorsiflexion and the lower thoracic and lumbar in ventroflexion. Lateral flexion is limited to less than 5° at all segments. The range in torsion is almost 180° and occurs primarily in the midthoracic region, T4-T11. Contrary to the depiction in most atlases, the standing cat exhibits several curvatures, including a mild dorsiflexion in the lower lumbar segments, a marked ventroflexion in the lower thoracic and upper lumbar segments, and a profound dorsiflexion in the upper thoracic (above T9) and cervical segments. The curvatures are not significantly changed by altering stance distance but are affected by head posture. During stance, the top of the scapula lies well above the spines of the thoracic vertebrae, and the glenohumeral joint is just below the bodies of vertebrae T3-T5. Using a simple static model of the vertebral column in the sagittal plane, it was estimated that the bending moment due to gravity is bimodal with a dorsiflexion moment in the lower thoracic and lumbar region and a ventroflexion moment in the upper thoracic and cervical region. Given the bending moments and the position of the scapula during stance, it is proposed that two groups of scapular muscles provide the major antigravity support for the head and anterior trunk. Levator scapulae and serratus ventralis form the lateral group, inserting on the lateral processes of cervical vertebrae and on the ribs. The major and minor rhomboids form the medial group, inserting on the spinous tips of vertebrae from C4 to T4. It is also proposed that the hypaxial muscles, psoas major, minor, and quadratus lumborum could support the lumbar trunk during stance. Received: 2 January 1997 / Accepted: 23 September 1997     

Spondylocarpotarsal synostosis syndrome and cervical instability

Spondylocarpotarsal synostosis syndrome is a recently delineated autosomal recessive condition comprising short stature with short trunk, failure of normal spine segmentation resulting in block vertebrae and fusion of posterior elements, carpal and/or tarsal coalition, scoliosis, lordosis, pes planus, dental enamel hypoplasia, decreased range of motion or dislocation of the elbow, renal anomalies, and hearing loss. The vertebral segmentation defects may involve noncontiguous areas of the cervical, thoracic, and lumbar spine. Odontoid hypoplasia was noted in two cases. We report on a sporadic case of spondylocarpotarsal synostosis in a 5-year-old girl with hypoplasia of C1 and odontoid and subluxation of C2 upon C3. This brings the number of well-documented cases of spondylocar- potarsal synostosis to 19, and is the first documenting cervical spine instability. Careful evaluation for this complication should be considered in other cases.     

The arterial supply of the cervical and thoracic spinal muscles and overlying skin: Anatomical study with implications for surgical wound complications

Postoperative spinal wound dehiscence is a significant complication following the posterior midline approach. It is postulated that this approach disrupts the vasculature supplying the paraspinal muscles and overlying skin. Although the spinal vasculature has been investigated previously, the smaller arterioles have not been described in the context of the posterior midline approach. Eight cadaveric neck and posterior torso specimens were dissected after injection with a radio‐opaque lead oxide mixture and subsequent radiographs taken were analyzed. The deep cervical, vertebral, superficial cervical, and occipital arteries consistently supplied the cervical paraspinal muscles. The latter two arteries also vascularized the overlying skin. The deep cervical arteries were found to be located lateral to the C3 to C6 vertebrae, vulnerable to damage with the posterior approach. In the thoracic region, the superior and posterior intercostal arteries consistently supplied the spinal muscles. In all specimens, two small anastomotic vessels posterior to the laminae were found connecting the intercostal artery perforators. Both the arterial perforators and their anastomotic channels were situated in the surgical field and susceptible to damage with the posterior approach. It is likely that the disruption in spinal vasculature contributes to the multifactorial problem of wound dehiscence with the posterior midline approach. Clin. Anat. 26:584–591, 2013. © 2012 Wiley Periodicals, Inc.     

Morphometric analysis of the relationships between intervertebral disc and vertebral body heights: an anatomical and radiographic study of the human thoracic spine

The main aim of this study was to provide anatomical data on the heights of the human intervertebral discs for all levels of the thoracic spine by direct and radiographic measurements. Additionally, the heights of the neighboring vertebral bodies were measured, and the prediction of the disc heights based only on the size of the vertebral bodies was investigated. The anterior (ADH), middle (MDH) and posterior heights (PDH) of the discs were measured directly and on radiographs of 72 spine segments from 30 donors (age 57.43 ± 11.27 years). The radiographic measurement error and the reliability of the measurements were calculated. Linear and non-linear regression analyses were employed for investigation of statistical correlations between the heights of the thoracic disc and vertebrae. Radiographic measurements displayed lower repeatability and were shorter than the anatomical ones (approximately 9% for ADH and 37% for PDH). The thickness of the discs varied from 4.5 to 7.2 mm, with the MDH approximately 22.7% greater. The disc heights showed good correlations with the vertebral body heights (R(2), 0.659-0.835, P-values < 0.005; anova), allowing the generation of 10 prediction equations. New data on thoracic disc morphometry were provided in this study. The generated set of regression equations could be used to predict thoracic disc heights from radiographic measurement of the vertebral body height posterior. For the creation of parameterized models of the human thoracic discs, the use of the prediction equations could eliminate the need for direct measurement on intervertebral discs. Moreover, the error produced by radiographic measurements could be reduced at least for the PDH.     

脊柱颈段的年龄变化及其临床意义

目的 为临床应用提供脊柱颈段年龄性变化的解剖学资料。方法 观察并测量了颈椎干骨标本50套(G3-7)、脊柱颈段标本正中矢状切标本15例(30侧,其中童尸2例,青年5例,中老年8例)、脊柱颈段X线正侧位片320张、CT片50张,分年龄段作统计,对特例作摄影和绘图记录。结果 (1)青少年时期同一椎体的前后面接近平行,并基本等高。随着年龄增加,前面逐渐变斜,朝向前上,前高则逐渐缩短,特别以C4-C6椎为显著,而后面的高度和斜度无显著变化。(2)在老年侧位片上,对同一椎的前、后面分别作垂线,两线相夹的角度C5-6均超过4°,而两端各椎则为3°。(3)颈椎间盘的前高和后高均随年龄老化而降低,但前高降低的总量约为后高者的2倍。(4)钩突年青时呈尖棘状,随着年龄老化向后扩展,变成矢状位的嵴状,此嵴前后长度在上位椎可超过同椎椎体的正中矢状径。(5)骨赘多见于钩突和C4-6椎体前面的上下缘,也可见于关节突和钩椎关节的斜坡,椎体后面可偶见后纵韧带骨化所成的骨赘或骨刺,罕见与前面相当的上、下缘骨唇形成。结论 颈曲随年龄增加而减小,决定因素是椎体前份和椎间盘前份高度的持续降低。     

Nucleus pulposus cells derived IGF-1 and MCP-1 enhance osteoclastogenesis and vertebrae disruption in lumbar disc herniation

Study design: Chronic strained lumbar disc herniation (LDH) cases were classified into bulging LDH, herniated LDH and prolapse LDH types according to imaging examination, and vertebrae disruptions were evaluated. Cytokines derived from the nucleus pulposus cells were detected, and their effects on osteoclastogenesis, as well as the mechanisms involved, were studied via an in vitro osteoclast differentiation system. Objective: To clarify the mechanisms of lumbar vertebrae resorption induced by lumbar herniation. Summary and background data: Chronic strained lumbar disc herniation induced vertebrae erosion exacerbates quality of patients’ life and clinical outcome. Although nucleus pulposus cells derived cytokines were reported to play an important role in this pathogenesis, the fundamental mechanisms underlying this process are still unclear. Methods: Chronic strained lumbar disc herniation patients were diagnosed with CT scan and T2-weighted magnetic resonance imaging. RNA was extracted from 192 surgical specimens of the herniated lumbar disc and 29 surgical excisions of the lumbar disc from spinal injury patients. The expressions of osteoclastogenesis related cytokines and chemokines were examined using real time PCR. Monocytes were induced into osteoclast with M-CSF and RANKL in vitro, while the IGF-1 and MCP-1 were added into the differentiation procedure in order to evaluate the effects and explore the molecular mechanisms. Results: Vertebrae erosion had a positive relationship with lumbar disc herniation severity types. In all of the osteoclastogenesis related cytokines, the IGF-1 and MCP-1 were the most highly expressed in the nucleus pulposus cells. IGF-1 enhances activation of NF-kB signaling directly, but MCP-1 upregulated the expression of RANK, so that enhanced cellular sensitivity to RANKL resulted in increasing osteoclastogenesis and activity. Conclusion: Lumbar herniation induced overexpression of IGF-1 and MCP-1 in nucleus pulposus cells aggravated vertebral erosions. Hence, this study suggests that targeting osteoclastogenesis related cytokines has potential clinical significance in the treatment of lumbar disc herniation patients.