单侧小关节分级切除对腰椎稳定性影响的三维运动研究

采用８具新鲜尸体腰椎功能单位，通过脊柱三维运动实验机施加最大载荷为１０．０Ｎｍ的６种力偶，使脊柱产生前屈／后伸、左／右侧弯和左／右轴向旋转运动。经立体摄像计算机图像处理得到Ｌ_２～Ｌ_３节段的运动范围（ＲＯＭ）、中性区（ＮＺ）和弹性区（ＥＺ）等参数。将完整标本测量的结果为自身对照组，然后在Ｌ_２、Ｌ_３节段依次切除左侧小关节１／３、１／２、和３／３。作ｔ检验和方差分析来分析单侧小关节切除对腰椎三维运动的影响。结果表明：单侧小关节切除１／３后ＲＯＭ增加不显著（Ｐ＞０．０５），不影响脊柱的稳定；小关节全切除后后伸、左侧弯和右旋的ＲＯＭ增加显著（Ｐ＜０．０５）。小关节切除１／２后ＲＯＭ虽增加不显著，但经方差分析与小关节全切的结果无明显差异，说明小关节切除范围超过１／２将导致脊柱失稳。     

后部结构对腰椎前屈／后伸稳定性的影响

目的：探讨小尾寒羊L5／6后部结构分级切除对腰椎前屈／后伸稳定性的影响。方法：利用改良的定位移生物力学测试方法,对L5／L6后部结构依次分级切除：Ⅰ正常→Ⅱ全椎板减压→Ⅲ左侧关节突切除1／2→Ⅳ左侧关节突全部切除→Ⅴ右侧关节突切除1／2→Ⅵ右侧关节突全部切除,Instron8874试验机依次测试标本前屈／后伸椎间运动的变化。结果：全椎板减压和左侧关节突的全部切除对于前屈／后伸的稳定性影响不大（P〉0．05）;当再切除右侧关节突1／2时,稳定性影响明显（P〈0.05）。结论：在保证手术视野的情况下,腰椎后路手术力求做到微创,尽量保留后部结构的完整性。     

单节段腰椎后部结构逐级切除对脊柱三维运动稳定性的影响

目的 观察单节段脊柱后部结构对腰椎三维运动稳定性的影响。方法 选用6具成人新鲜尸体脊柱标本腰1-骶1(L1～S1)，采用单节段逐步切除腰椎后部结构的方法，形成7种状态，通过脊柱三维运动试验机施加10N．m的载荷，使脊柱产生前屈／后仲，左／右侧屈和左／右轴向旋转运动。结果 切除脊柱的后部结构后，在脊柱的三维稳定性中，前屈及轴向旋转运动的稳定性最易受到破坏，前屈平均运动范围增加5．1度，旋转增加3．4度。结论 除小关节骨性结构及关节囊外，后部结构对维持腰椎的稳定性具有重要作用，特别是对前屈及轴向旋转运动。     

下颈椎经关节螺钉钉棒系统固定的生物力学研究

目的：比较下颈椎三柱损伤后单独经关节螺钉固定（TAS）、经关节钉棒系统同定（TRS）和侧块螺钉钉棒系统固定（LRS）的三维稳定性。方法：12具新鲜颈椎标本．制成C4／5、C5／6节段三柱损伤模型，分别进行单独经关节螺钉（TAS组）、经关节螺钉钉棒系统（TRS组）和侧块螺钉钉棒系统（LRS组）三种方法固定，在非限制性和非破坏性的实验条件下测试其前屈、后伸、左右侧弯和轴向旋转运动状态的稳定性。结果：TAS组和TRS组在各方向的运动范同（ROM）和中性区（NZ）的均数均显著小于完整标本组，差异有统计学意义（P〈0．05）；LRS组在前屈、后伸、侧弯运动中的ROM和NZ与完整标本组比较有显著降低，差异有统计学意义（P〈0．05）；LRS组在旋转运动中的ROM和NZ与完整标本组比较有不同程度的降低，但差异无统计学意义（P〉0．05）。TAS、TRS在各个方向稳定性明显优于LRS组（P〈0．05）。TRS在前屈运动中的ROM和NZ与TAS组比较有所减小，但无统计学意义（P〉0．05）；在后伸、侧弯和旋转运动中，TRS组稳定性明显优于TAS组，有统计学意义（P〉0．05）。结论：在下颈椎三柱损伤选择经关节固定技术时以钉棒形式同定稳定性更好。     

胸腰段脊柱韧带分级切断对脊柱稳定性影响实验研究

目的：研究胸腰段脊柱韧带逐级切断对脊柱节段稳定性影响的三维运动变化。方法：采用７ 具新鲜胸腰段脊柱通过脊柱三维运动试验机施加最大载荷为１０．０Ｎ．ｍ 的６ 种力偶,使脊柱产生前屈、后伸、左／右侧屈和左／右轴向旋转运动。经立体摄像计算机图像处理得到Ｔ１２ ～Ｌ１ 节段的运动范围。先对完整标本进行测量,其结果为自身对照组（Ⅰ组）。然后在Ｔ１２～Ｌ１ 节段依次切断棘上韧带（Ⅱ组）,棘间、黄韧带（Ⅲ组）,关节囊韧带（Ⅳ组）后纵韧带、椎间盘后１／３（Ⅴ组）。结果：切除棘上、棘间韧带后活动范围均有增加,但和对照组相比差异无显著性（Ｐ＞ ０．０５）。切除关节囊韧带后前屈运动和左／右旋转运动范围显著增大和对照组相比差异有显著性（Ｐ＜ ０．０５）,切除后纵韧带、椎间盘后１／３,在Ⅳ组基础上活动范略有增大和正常组相比差异有显著性（Ｐ＜ ０．０５）。结论：胸腰段脊柱关节囊韧带可提供该节段的前屈,左／右旋转运动的内在稳定性。     

下胸段经关节突入路椎间盘切除术对脊柱稳定性影响的观察

目的：观察下胸段经关节突入路椎间盘切除术对脊柱稳定性的影响。方法：采用新鲜成人尸体下胸椎标本（T9～L1）6具,在T11～T12节段建立4种经关节突入路椎间盘切除模型：（1）单侧关节突切除＋椎间盘摘除（ULF＋D）;（2）单侧关节突切除＋全椎板减压＋椎间盘摘除（ULF＋L＋D）;（3）双侧关节突切除＋全椎板减压＋椎间盘摘除（BLF＋L＋D）;（4）双侧关节突切除＋全椎板减压＋椎间盘摘除＋单节段椎弓根钉棒固定T11～T12,于前屈,后伸,左、右侧曲和旋转6个方向进行加载,记录100N载荷下的ROM值。将4种模型ROM值分别与完整标本的ROM值按照配对t检验比较进行统计学分析。结果：与完整标本比较,ULF＋D在旋转方向的ROM值有显著性差异,ULF＋L＋D和BLF＋L＋D在6个方向上的ROM值均有显著性差异（P〈0.05）;T11～T12椎弓钉棒系统固定后在轴向旋转和前屈方向的ROM值无显著性差异（P〉0.05）,在其他三个方向上存在显著性差异（P〈0.01）。结论：ULF＋L＋D和BLF＋L＋D对脊柱下胸段6个方向上的稳定性均有显著性影响,辅以椎弓根钉固定相应节段,能够显著恢复脊柱稳定性。     

颈椎前路钛网钢板内固定及自体髂骨植骨在不同颈椎节段中的生物力学研究

目的 采用颈椎前路钛网钢板及自体髂骨植骨对不同颈椎节段进行内固定，分析其生物力学改变。方法 取自愿捐赠的6具新鲜尸体C3～7标本，C5、C5.6及C4～6椎体次全切除后，分别行髂骨植骨和钛网前路钢板内固定术，测量各节段的前屈、后伸、左、右侧弯及左、右旋转运动变化，以完整标本作为对照组。结果 自体髂骨的植入使失稳颈椎的稳定性提高，其侧弯、屈伸运动度减少，与对照组比较，差异有统计学意义（P〈0．05），但抗旋转运动减少不明显（P〉0．05）。不同颈椎节段开槽减压椎间撑开钛网前路钢板内固定状态下，手术节段的即刻稳定性比对照组及撑开植骨状态增加（P〈0．05）。结论 颈椎前路椎体次全切除之后，植骨仅能部分改善其稳定性，但应用颈椎前路钛网钢板内固定可明显增强颈椎的稳定性，也较完整颈椎运动功能单位稳定。     

双侧小关节分级切除对腰椎稳定性影响的三维运动研究

采用８具新鲜尸体腰椎功能单位，通过脊椎三维运动实验机施加最大载荷为１０．０Ｎ．ｍ的６种力偶，使脊柱产生前屈，后伸，左右侧弯和左，右轴向旋转运动。经立体摄像计算机图像处理得到Ｌ１－２节段的运动范围（ＲＯＭ），中性区（ＮＺ）和弹性区（ＥＺ）等参数。首先对完整标本进行测量，测得的结果为自身对照组，然后在Ｌ１－２节段依次切除双侧小关节１／３，１／２和３／３，根据节段间的运动变化，定量地分析小关节切除对腰椎     

颈椎前路静力性与动力性钉板系统在三柱不稳定损伤中生物力学性能的比较

目的比较颈椎前路静力性、动力性钉板系统在三柱屈曲牵张型不稳定损伤中的生物力学测试结果，为临床提供生物力学依据。方法采用6具小牛颈椎标本，在C4、5节段制作屈曲牵张损伤模型，切除椎间盘、植骨后，随机分为3组，分别采用Orion、Codman、Window钢板螺钉固定，分别测定正常颈椎及固定后脊柱在前屈、后伸、旋转运动时的稳定性并与正常标本比较。结果3种钢板固定后的活动度（ROM）与正常颈椎相比要大。其中Orion在前屈、后伸、侧屈与正常相比无显著的差异（P〉0．05）；Codman和Window在前屈、后伸时与正常相比有显著的差异（P〈0．05）；Codman在侧屈时正常相比无显著的差异（P〉0．05），Window侧屈时与正常相比有显著的差异（P〈0．05）；3种钢板在旋转时与正常相比均有显著的差异（P〈0．05）。结论在三柱屈曲牵张型不稳定损伤的模型中，前路静力化固定相对稳定，动力化固定可能降低一定的固定强度，尤其是选择平移类设计的钢板固定应慎重。     

短节段DRFS脊柱内固定术后即刻刚度的变化及其意义

目的测试短节段猪脊柱标本在完整、失稳后及内固定后的刚度变化。方法选择12节段猪脊柱标本12具,测定其前屈、后伸、侧屈及旋转时的刚度;切除椎间盘、小关节及前后纵韧带松解脊柱,测定其各项运动刚度;用DRFS脊柱内固定系统进行短节段内固定后重复测试各项运动刚度。结果与完整脊柱的刚度（前屈、后伸、侧屈及旋转的刚度分别为0.389±0.305,1.090±0.355,1.012±0.301,1.232±0.441,1.103±0.414,1.013±0.402）相比,失稳后脊柱各项运动的刚度（前屈、后伸、侧屈及旋转的刚度分别为0.216±0.218,0.278±0.204,0.255±0.124,0.409±0.169,0.633±0.218,0.626±0.216）均明显减少（P〈0.05）,而内固定后脊柱各项运动的刚度（前屈、后伸、侧屈及旋转的刚度分别为（0.568±0.351,0.679±0.151,0.759±0.314,0.729±0.311,1.006±0.304,0.975±0.218）均明显高于失稳后脊柱,与完整脊柱前屈、侧屈及旋转运动无明显差异,后伸运动的刚度明显高于完整脊柱（P〈0.01）。结论短节段脊柱内固定后各项运动的刚度明显高于脊柱失稳后,与完整标本相比除后伸运动的刚度明显增高外,其余各方向的运动刚度相近。     

Biomechanical evaluation of lumbar spinal stability after graded facetectomies

In an in vitro experiment using fresh human lumbar functional spinal units, the effects of the division of the posterior ligaments (consisting of the supraspinous/interspinous ligaments) and graded facetectomies were investigated. The graded facetectomies consisted of unilateral and bilateral medial facetectomies, and unilateral and bilateral total facetectomies. Six kinds of moments were applied and ranges of motion (ROM) and neutral zones (NZ) were determined three-dimensionally by stereophotogrammetric methods. Range of motion was not affected by the division of the supraspinous/interspinous ligaments for all load modes. In flexion, ROM increased slightly after unilateral medial facetectomy. In right axial rotation, ROM increased after left unilateral total facetectomy. Range of motion was not affected, even by bilateral total facetectomies, in extension and lateral bendings. This study suggested that medial facetectomy does not affect lumbar spinal stability, and conversely, total facetectomy, even created unilaterally, makes the lumbar spine unstable.     

Posterior lumbar interbody fusion using posterolateral placement of a single cylindrical threaded cage

STUDY DESIGN: An in vitro biomechanical study of posterior lumbar interbody fusion (PLIF) with threaded cages was performed on 18 bovine lumbar functional spinal units. OBJECTIVES: To compare the segmental stiffness among PLIF with a single long posterolateral cage, PLIF with a single long posterolateral cage and simultaneous facet joint fixation, and PLIF with two posterior cages. SUMMARY OF BACKGROUND DATA: In most cases, PLIF with threaded cage techniques needs bilateral facetectomy, extensive exposure, and retraction of the cauda equina. Posterior element deficiency is detrimental to postoperative segmental stiffness. METHODS: All specimens were tested intact and with cage insertion. Group 1 (n = 12) had a long threaded cage (15 x 36 mm) inserted posterolaterally and oriented counter anterolaterally on the left side by posterior approach with left unilateral facetectomy. Group 2 (n = 6) had two regular-length cages (15 x 24 mm) inserted posteriorly with bilateral facetectomy. Six specimens from Group 1 were then retested after unilateral facet joint screw fixation in neutral (Group 3). Similarly, the other six specimens from Group 1 were retested after fixation with a facet joint screw in an extended position (Group 4). Nondestructive tests were performed in pure compression, flexion, extension, lateral bending, and torsion. RESULTS: The PLIF procedure involving a single cage (Group 1) had a significantly higher stiffness than PLIF with two cages (Group 2) in left and right torsion (P < 0.05). Group 1 had higher stiffness values than Group 2 in pure compression, flexion, and left and right bending, but differences were not significant. Group 3 had a significant increase in stiffness in comparison with Group 1 for pure compression, extension, left bending, and right torsion (P < 0.05). For Group 4, the stiffness significantly increased in comparison with Group 1 for extension, flexion, and right torsion (P < 0.05). Although there was no significant difference between Groups 3 and 4, Group 4 had increased stiffness in extension, flexion, right bending, and torsion. CONCLUSIONS: Posterior lumbar interbody fusion with a single posterolateral long threaded cage with unilateral facetectomy enabled sufficient decompression while maintaining most of the posterior elements. In combination with a facet joint screw, adequate postoperative stability was achieved.     

后部结构分级切除对下腰椎稳定性影响的实验研究

目的 探讨小尾寒羊L5,6后部结构分级切除对腰椎稳定性的影响.方法 选取14只小尾寒羊,截取L4～L7脊柱标本.实验前摄正、侧位X线片以排除脊柱疾患,CT定位关节突关节分级切除.对L5,6节段后部结构依次分级切除如下:Ⅰ正常→Ⅱ全椎板减压→Ⅲ左侧关节突切除1/2→Ⅳ左侧关节突全部切除→Ⅴ右侧关节突切除1/2→Ⅵ右侧关节突全部切除→结束.利用Instron 8874液压伺服动态生物力学测试系统依次测试标本六个自由度上椎间运动的变化,计算平均刚度.利用SPSS 11.5行单因素方差分析,检验水准α值取0.05.结果 全椎板减压和左侧关节突的全部切除对于前屈或后伸的稳定性影响不大;当再切除右侧关节突1/2时,前屈或后伸的平均刚度比正常时分别下降32.33%和30.83%.腰椎后路结构的切除对于腰椎侧弯的稳定性影响不大.全椎板减压即出现左和右扭转失稳,平均刚度分别比正常时下降26.13%和26.20%,关节突关节与扭转的稳定性亦具有重要意义,特别是对对侧扭转的稳定性.结论 行腰椎后路手术时,在保证手术视野的情况下,力求做到微创,尽量保留后部结构的完整性.     

单侧小关节分级切除对同节段腰椎间孔形态影响的实验研究

[目的]了解单侧腰椎小关节分级切除对不同运动状态下同节段腰椎间孔形态变化的影响机制.[方法]取8例新鲜尸体脊柱腰段完整标本,依次进行分级切除L4j的后部结构,造成5种减压情况,依次测量加载前后各组L4、5椎间孔高度及最大、最小宽度值并比较分析.[结果]①完整组标本负载荷状态下,L4、5椎间孔各孔径均减小而且变化存在显著性差异;以扭力矩加载时,L4、5椎间孔高度及最大、最小宽度分别在中立位、后伸、同侧弯状态下三者均显著减小,在前屈、对侧弯状态下明显增大;②在中立位、后伸位和同侧弯体位负载时,当腰椎单侧小关节切除大于1/2后,L4、5椎间孔孔径均有显著性差异.[结论]在外科操作进行后部结构切除手术时,尤其是小关节切除手术应严格掌握指征.     

椎管重建内固定术有限元模型的构建及稳定性分析

目的:构建椎管重建内固定术的有限元模型,并分析椎管重建内固定术对脊柱稳定性的影响,验证椎管重建内固定术在椎管内手术中的有效性和可靠性。方法:筛选1名30岁男性,身高172 cm,体重75 kg的健康志愿者并采集其腰椎CT资料,建立正常腰椎L₃-L₅的有限元模型,并与体外实体结果和已发表的有限元分析结果进行比较,以验证该模型的有效性。根据处理方式不同分为正常组、椎板切除组和椎管重建组。在相同边界固定和生理载荷条件下,实施前屈、后伸、左弯、右弯、左旋和右旋6种工况活动,分析6种工况活动下L₃-L₄和L₄-L₅观察节段的活动度(range of motion,ROM)和L₃-L₅整体最大ROM的变化情况。结果:构建的L₃-L₅有限元模型各节段ROM位移与体外实体结果和既往文献数据结果吻合,确认了该模型的有效性。在L₃-L₄中,椎管重...     

Biomechanical studies of a dynamized anterior thoracolumbar implant

STUDY DESIGN: An in vitro investigation into the biomechanical properties of a dynamized anterolateral compression implant that allows controlled subsidence. OBJECTIVES: To determine the extent to which both modes of the anterolateral compression implant (controlled collapsing and rigid) are able to reestablish the stability of the lumbar spine after L4 corpectomy. SUMMARY OF BACKGROUND DATA: Over time, anterior and posterior spinal implants have been associated with progressive angulation, and occasionally implant failure and breakage. To circumvent this occurrence and provide better graft loading, dynamized or collapsing devices for clinical use have been developed. METHODS: Eight fresh calf spines (L1-L6) were placed in a biomechanical testing frame. Pure moments of 6 Nm were loaded onto the intact spine in six directions: flexion, extension, right and left lateral bending, and right and left axial rotation. A total L4 corpectomy then was performed, and the defect grafted with a wooden dowel. Loading was repeated after the specimens were stabilized using the two modes of the anterolateral compression implant in succession. RESULTS: The results showed that both modes of the implant (the rigid mode in particular) restore the stiffness of the unstable spine to normal levels of flexion, extension, and right and left lateral bending, even to levels exceeding normal. These devices, however, fall short of achieving normal stability in right and left axial rotation. CONCLUSION: In the cadaveric calf spine after L4 corpectomy, restoration of stability with a dynamized anterior spinal implant is possible in flexion, extension, and right and left lateral bending, but not in axial rotation.     

Biomechanical studies on two anterior thoracolumbar implants in cadaveric spines

STUDY DESIGN: A biomechanical comparison of two commonly used anterior spinal devices: the Smooth Rod Kaneda and the Synthes Anterior Thoracolumbar Spinal Plate. OBJECTIVES: To compare the stability imparted to the human cadaveric spine by the Smooth Rod Kaneda and Synthes Anterior Spinal Plate, and to assess how well these devices withstand fatigue and uni- and bilateral facetectomy. SUMMARY OF BACKGROUND DATA: Biomechanical studies on the aforementioned and similar devices have been performed using synthetic, porcine, calf, or dog spines. As of the time of this writing, studies comparing anterior spinal implants using human cadaveric spines are scarce. METHODS: An L1 corpectomy was performed on 19 spines. Stabilization was accomplished by an interbody wooden graft and the application of the Smooth Rod Kaneda in 10 spines and the Synthes Anterior Spinal Plate in the remaining 9. Biomechanical testing of the spines was performed in six degrees of freedom before and after stabilization, and after fatiguing to 5000 cycles of +/- 3 Nm of flexion and extension. Testing was repeated after uni- and bilateral facetectomy. RESULTS: After stabilization, the Smooth Rod Kaneda was significantly more rigid than the anterior thoracolumbar bar spinal plate in extension. After fatigue, the Smooth Rod Kaneda was significantly stiffer than the anterior thoracolumbar spinal plate in flexion, extension, right lateral bending, left lateral bending, and right axial rotation. A significant decrease in stiffness was noted with the Synthes device in flexion after bilateral facetectomy compared with the stabilized spine. CONCLUSIONS: The smooth Rod Kaneda device tends to be stiffer than the anterior thoracolumbar spinal plate, particularly in extension, exceeding the anterior thoracolumbar spinal plate in fatigue tolerance. The spine stabilized with the anterior thoracolumbar spinal plate is more susceptible to the destabilizing effect of bilateral facetectomy than than that stabilized with the Smooth Rod Kaneda. The additional rigidity encountered with the Smooth Rod Kaneda must be weighed against the simplicity of anterior thoracolumbar spinal plate application.     

脊柱三维运动分析系统及其在腰椎稳定性分析中的应用

脊柱三维运动的测量是分析脊柱三维运动的基础。由电子计算机三维立体视觉模型建立的脊柱三维测量系统，在椎骨上设置有三个不共线标志的标尺，由互相成角度的两个摄像机将标尺运动的图像输入计算机图像处理系统，通过对标志点的识别、定位，分析脊柱节段的三维运动。     

腰椎横突间入路椎体间融合术的生物力学评价

目的 观察腰椎横突间入路椎体间融合术(ILIF)及附加椎弓根钉固定后的生物力学稳定性.方法 采用小牛脊柱运动节段标本12具,依序进行不同处理后分为以下7组:(1)正常对照组(IS);(2)左侧小关节切除+椎间融合器植入组(TLIF);(3)TLIF附加同侧椎弓根钉固定组;(4)TLIF附加双侧椎弓根钉固定组;(5)左侧横突间入路椎间融合器植入组(ILIF);(6)ILIF附加同侧椎弓根钉固定组;(7)ILIF附加双侧椎弓根钉固定组.分别测试各组在轴向压缩、前屈、后伸、左右侧屈时的载荷-应变、载荷-位移变化以及轴向刚度和双向扭转稳定性等生物力学指标,并进行统计学比较.结果 所有生物力学指标中ILIF组稳定性均大于TLIF组(P<0.05),在定量扭矩扭角方面差距最大达72%.ILIF+BPSF的稳定性最高,在前屈载荷应变方面较IS组差异最大达53%,而ILIF+HPSF组与ILIF+BPSF组比较差异无统计学意义(P>0.05). 结论 ILIF手术生物力学稳定性优于TLIF手术;ILIF附加同侧椎弓根钉固定与附加双侧椎弓根钉固定生物力学稳定性相当,使用ILIF术式附加侧同椎弓根螺钉固定,可提供较好的即刻稳定性.