棘突撑开与小关节、椎间孔形态变化关系的初步实验研究

目的 观察棘突撑开程度与小关节移位、椎间孔形态变化的关系.方法 使用6具新鲜腰椎尸体,制作标本,保留关节突周围关节囊韧带及棘间韧带,通过分别撑开L3/4,L4/5棘突,测量相应节段小关节间相对位移、椎间孔高度及宽度改变.结果 棘突撑开2 mm、4 mm后,L3/4、L4/5腰椎间孔高度增大、小关节位移改善均有明显差异,椎间孔宽度的改变在撑开2 mm无明显差异,在撑开4 mm时宽度增大有统计学差异.结论 棘突撑开能有效改善小关节位移、增加椎间孔高度,但对于椎间孔宽度的增加需要撑开足够距离.     

椎弓根螺钉固定对头端关节突关节影响的研究进展

<正>双侧的关节突关节和椎间盘组成的三关节复合体是维持脊柱运动节段稳定的重要结构。脊柱固定时椎弓根螺钉置入导致的头端关节突关节损伤可增加相邻节段椎间盘的压力和关节突关节负荷~([1]),同时降低脊柱的稳定性~([2]),加快相邻节段的退变,被认为是脊柱融合固定术后相邻节段退变性疾病(adjacent segment disease,ASD)发生的危险因素之一~([3~6])。椎弓根螺钉的置入方式可分为开放置钉和     

非融合棘突间撑开器治疗腰椎早期退变性腰痛的三维有限元分析

目的建立非融合棘突间撑开器(IPD)及腰椎L4、5节段有限元模型,对撑开器植入前后力学环境进行研究。方法腰椎行CT扫描,根据CT生成实体模型,与撑开器模型一起导入PATRAN生成有限元模型,施加中立位及后伸负荷分析椎间盘受力。结果中立位负荷时IPD受力小;后伸时IPD可分担椎间盘负荷,但L5椎弓根负荷增大。结论基于CT及CAD可建立非融合棘突间撑开器及腰椎的有限元模型,棘突间撑开器可分担后伸时椎间盘的负荷,但可能会增加L5椎弓根崩裂的危险。     

棘突间移植物治疗腰椎关节突关节退变的初期结果

目的 评价棘突间移植物-DIAM(device for intervertebral assisted motion)对腰椎关节突关节退变的治疗效果及相关术中、术后并发症.方法 对2005年8月至2006年4月接受DIAM移植的22例患者进行回顾性分析.女14例,男8例;平均年龄38.5(24～59)岁.单节段14例,双节段8例;单发腰椎关节突关节退变诱发腰痛16例(其中3例为腰椎人工间盘置换术后残留腰痛),腰椎间盘突出3例,腰椎管狭窄伴间歇性跛行2例,腰椎间盘后路摘除术后1例.结果手术时间为25 min(单节段)和35 min(双节段).术后所有患者随访16～28个月,平均17个月.术后影像学检查显示移植物无明显迁移.正位X线片显示移植物撑开了棘突间间隙,侧位X线片显示神经根管高度、椎间隙后高度术前及术后66周的比较差异有统计学意义(P<0.01).术后症状改善程度采用Odom评估法,优7例,良10例,可1例,差4例;优良率77.3%.视觉模拟评分由术前平均(7.09±0.92)分改善至术后66周平均(3.23±1.82)分,差异有统计学意义(P<0.01).随访期间未发生症状加重、移植物松脱及术后翻修.结论 应用棘突间移植物技术治疗单发的腰椎关节突关节退变,保留了腰椎后柱结构稳定性,操作简单.通过棘突间撑开作用降低了关节突关节的应力,增加了神经根管高度,恢复了腰椎后柱高度.     

腰椎椎间孔成形幅度对关节突关节应力变化的有限元分析

目的建立L_(3~5)三维有限元模型,分析椎间盘摘除并不同幅度椎间孔成形前后对L_4/L_5关节突关节应力分布的影响。方法选取1名既往无腰椎疾病史的20岁男性志愿者,获取其腰椎CT数据构建有限元模型并验证其有效性。在L_4/L_5椎间盘中度退变模型(M1)的基础上,模拟经椎间孔入路经皮内窥镜技术,去除椎间盘左后侧约1/4纤维环中部及1/4髓核,模拟腰椎椎间盘摘除术,构建模型M2;以圆柱体代替环锯模拟切除L_5上关节突部分骨质行椎间孔扩大成形,构建一级椎间孔成形模型M3(环锯直径5.0 mm)、二级椎间孔成形模型M4(环锯直径6.5 mm)和三级椎间孔成形模型M5(环锯直径7.5 mm)。给予特定加载条件,比较模型在前屈、后伸、左右侧曲、左右旋转6种工况下L_4/L_5关节突关节应力变化。结果建立的L_(3~5)三维有限元模型有效。M1模型在各种工况下L_4/L_5关节突关节的应力左侧较右侧大。M2模型在前屈工况下左侧L_4/L_5关节突关节应力下降,右侧应力上升;在后伸工况下左侧应力上升,右侧应力下降;在右旋工况下,左侧应力变化不明显,右侧应力稍下降;在左侧屈及左旋工况下两侧应力均上升;在右侧屈工况下左侧应力稍下降,右侧应力变化不明显。除M5模型左旋工况下右侧应力增加明显外,其他各种工况下M3、M4、M5模型应力变化不明显。结论椎间盘摘除后引起病变节段关节突关节面所承载的负荷不对称;在精确穿刺的指引下,环锯直径5.0、6.5、7.5 mm行椎间孔成形对病变节段关节突关节应力变化无显著影响。     

腰椎关节突人工关节的初步研究

目的探讨临床应用腰椎关节突人工关节的可行性。方法选择12具国人尸体腰椎标本,测量椎体和椎间盘高度;研制假体装置ZJS,并应用于3例退行性腰椎管狭窄并失稳患者,重建腰椎稳定性,不做椎骨间植骨融合,观察其腰腿疼症状的缓解程度、X光片测量腰椎活动度和椎间盘高度,评价其初步的临床疗效。结果国人腰椎椎体后缘高度(23.43±3.10)mm~(34.45±3.28)mm,椎间盘后缘高度(5.38±1.36)mm~(7.96±2.05)mm。3例患者随访11~16个月,症状明显缓解,满意程度高。术后X片显示手术椎节活动度:前屈后伸3°,左右侧屈3.5;°手术节段椎间盘后缘间隙高度能维持于中立位状态3.5~4.5 mm,在脊柱后伸活动时该高度亦无明显降低。结论国人腰段脊柱具备置入ZJS的条件;近期临床观察结果显示,退行性腰椎管狭窄并失稳患者经后路椎管减压,置入ZJS既能重建腰椎稳定性,保持手术节段的椎间孔高度,又能保留手术椎节的部分活动功能,是一种值得进一步研究的治疗腰椎退行性病变的非融合手术技术。     

胸椎关节突关节解剖学测量与经关节螺钉固定的关系

目的测量胸椎关节突关节的相关数据,并探讨与经关节螺钉固定的关系。方法选取20具福尔马林液体浸泡保存的成人尸体胸椎标本,去除所有肌肉、韧带等软组织,对胸椎每个节段从椎间盘和关节间隙进行游离,清楚暴露出各个关节面。测量胸椎关节突关节上、下关节面的高度、宽度和厚度,分析与经关节螺钉固定的关系。结果胸椎关节突关节的关节面高度、宽度和厚度的左右侧数据稍有不同,但无明显统计学意义(P0.05)。胸椎上关节面的高度9.10～11.21mm,宽度8.45～11.07mm,厚度3.87～5.71mm;胸椎下关节面的高度10.65～12.59mm,宽度9.80～12.60mm,厚度4.20～6.01mm。结论胸椎关节突关节复合体有着足够的皮质骨供螺钉行跨关节固定,胸椎经关节固定也许可以作为椎弓根螺钉应用的一种补充方法。     

角度人工颈椎间盘置换对关节突应力的影响

目的探讨带角度人工颈椎间盘置换后关节突及相邻关节突应力变化。方法选择400名西北地区40岁以上人群颈椎侧位X线片,计算机辅助设计软件测量颈椎间盘角,设计10°人工颈椎间盘;对已建立的C4、C5两节段带椎间盘的正常颈椎有限元模型、C4、5置换0°椎间盘假体和置换10°椎间盘假体后的颈椎模型进行轴向加压、前屈/后伸、侧弯、扭转加载,对比观察C4、5关节突应力变化;对已建立的C4～C6三节段带椎间盘的正常颈椎有限元模型、C4、5置换0°椎间盘假体和置换10°椎间盘假体后的颈椎模型同样方式进行加载,对比置换节段及相邻节段的关节突应力变化。结果 C3～C7椎间盘角分别为:C3、4(9.97±3.64)°,C4、5(9.95±4.34)°,C5、6(8.59±3.75)°,C6、7(8.49±3.39)°,各椎间隙之间椎间盘角两两比较,C3、4与C4、5,C5、6与C6、7差异无统计学意义(P>0.05),其余各椎间隙之间差异均有统计学意义(P<0.05)。C4、C5两节段模型加载中,轴向加载下三者等效剪应力(Se)无明显差异;前屈/后伸时正常模型Se最大,10°假体置换组最小;侧弯时正常椎体Se最大,10°假体置换组最小;扭转时10°假体置换组更接近正常椎体生理状态力学特性。C4～C6三节段模型加载中,C4、5节段的关节突关节Se在轴向加载、前屈/后伸、侧弯时较正常椎体明显减小;扭转时减小不明显,接近正常状态。相邻下位节段C5、6关节突应力在轴向加载和侧弯时应力明显减小,扭转时应力减小较少,前屈/后伸时无明显改变,接近正常节段力学特性。结论 10°椎间盘假体植入椎间隙对颈椎相邻节段的关节突应力影响小,接近正常颈椎间盘力学性能。     

不同椎板减压范围对BioFlex系统生物力学的影响

【摘要】 目的：利用有限元方法分析比较不同椎板减压范围对脊柱动态内固定BioFlex系统生物力学的影响。方法：利用Mimics 10.01三维重建软件建立正常L3～L5几何模型并利用ProE逆向工程软件建立BioFlex系统几何模型,按临床术式进行组装并导入ANSYS Workbench 14.0有限元分析软件进行前处理建立四种L3～L5三维有限元模型：完整状态L3～L5模型（INT组）,L4-L5椎板减压+1/2关节突切除+Bioflex模型（MF-BF组）,L4-L5椎板减压+全关节突切除+Bioflex模型（TF-BF组）,L4-L5椎板减压+髓核摘除+Bioflex模型（D-BF组）;在各模型L3椎体的上表面以及上关节突的关节面轴向予1200N载荷和8Nm、8Nm、6Nm、4Nm力矩下模拟人体腰椎正常生理轴向载荷、前屈、后伸、侧弯和扭转,L5椎体的下表面及下关节突表面各节点六个方向自由度完全固定。测量各模型固定节段和邻近节段的活动度以及邻近节段的髓核间应力与关节突应力,并进行分析比较。结果：椎板减压并置入动态内固定Bioflex系统后,脊柱固定节段的活动度各减压组较INT组明显减小（P＜0.05）,其中TF-BF组前屈活动度减小幅度最大达77.2%,MF-BF组后伸、侧弯、旋转活动度减小幅度最大分别达37.4%、67.2%、83.1%;邻近节段的活动度各减压组较INT组增大（P＜0.05）,其中MF-BF组前屈活动度增大幅度最大达22.9%,TF-BF组后伸、侧弯活动度增大幅度最大分别达18.2%、32.1%,DF-BF组旋转活动度增大幅度最大达13.8%。不同状态下固定节段及邻近节段活动度MF-BF组、TF-BF组及D-BF组间波动幅度不大,两两比较差异无统计学意义（P＞0.05）。邻近节段关节突应力及髓核间应力各减压组较INT组明显增大（P＜0.05）,其中TF-BF组关节突应力在后伸、旋转活动时增大幅度最大分别达81.6%、77.3%,DF-BF组关节突应力在侧弯活动时增大幅度最大达60.5%,DF-BF组髓核间应力在前屈活动时增大幅度最大达46.6%,MF-BF组髓核间应力在后伸、侧弯、旋转活动时增大幅度最大分别达11.8%、63.5%、51.3%;邻近节段的关节突应力与髓核间应力在不同状态下各减压组间波动幅度不大,两两比较差异无统计学意义（P＞0.05）。结论：置入BioFlex系统后脊柱固定节段的活动度明显减小,邻近节段的活动度增大,固定与邻近节段活动度不随椎板减压范围的改变而明显改变;邻近节段关节突应力及髓核间应力明显增大,其大小不随椎板减压节段范围的改变而明显改变。     

Wallis棘突间动态稳定装置的生物力学研究

目的 观察Wallis棘突间动态稳定装置对腰椎力学载荷传导及活动度的影响.方法 采用6具新鲜成人脊柱标本(L1～S1),采用自身前后对照,分为正常组、损伤组、椎弓根螺钉固定组、置入Wallis装置组,分别测量中立位、前屈后伸、左右侧弯、旋转运动加载下节段腰椎的力学载荷及活动范围.结果 W组固定节段椎间盘、关节突应力载荷明显小于Ⅰ组(P＜0.05),明显大于PS组(P＞0.05),但与N组比较差异无统计学意义(P＞0.05);临近节段椎间盘、关节突应力载荷与Ⅰ组、N组比较差异无统计学意义(P＞0.05),但明显小于PS组(P＜0.05).W组固定节段的屈伸活动范围(ROM)小于Ⅰ组及N组(P＜0.05),但明显大于PS组(P＜0.05);侧弯及旋转运动范围,W组与Ⅰ组比较差异无统计学意义(P＞0.05),但与N组及PS组比较差异有统计学意义(P＜0.05).结论 Wallis棘突间动态稳定装置限制固定节段的异常活动,降低固定及临近节段椎间盘及关节突关节应力载荷,减小邻近节段应力集中.     

Effects of a new shape‐memory alloy interspinous process device on pressure distribution of the intervertebral disc and zygapophyseal joints in vitro

Objective: To quantify the pressure distribution of lumbar intervertebral discs and zygapophyseal joints with different degrees of distraction of the interspinous processes by using a new shape‐memory interspinous process stabilization device, and to research the relationship between changing disc and zygapophyseal joint loads and the degree of distraction of interspinous processes, and thus optimize usage of the implant. Methods: Six cadaver lumbar specimens (L₂–L₅) were loaded. The loads in disc and zygapophyseal joints were recorded at each L_3‐4 disc level. Implants with different spacer heights were then placed by turn and the pressure measurements repeated. Results: An implant with 10 mm spacer height does not significantly share the load. A 12 mm implant reduces the posterior annulus load, and meanwhile decreases the zygapophyseal joints pressure, but only in extension. A 14 mm implant shares the loads of posterior annulus, nucleus, and zygapophyseal joints in extension and the neutral position, but slightly increases the anterior annulus' load. Though 16–20 mm implants do decrease the loads in the posterior annulus and zygapophyseal joints, the anterior annulus' load was apparently increased. Conclusion: Different degrees of distraction of the interspinous processes lead to different load distribution on the intervertebral disc. The implant tested is not appropriate in cases of serious spinal stenosis because of the contradiction that, while over‐distraction of the interspinous processes decreases the posterior annulus and the zygapophyseal joints load and distracts the intervertebral foramina, it leads to a marked increase in the load of the anterior annulus, which is recognized to accelerate disc degeneration.     

腰椎棘突间撑开器的研究进展

腰椎棘突间撑开器作为动态稳定系统的重要内容,通过在棘突间置入撑开装置,除了对病变节段的后伸活动有一定限制外,基本保留了椎间的生理活动,扩大了椎管以及椎间孔的容积,减轻了椎间盘后部的负荷,且对相邻节段的活动和负荷传递并没有明显的影响。从现有的资料来看,多种棘突间撑开器的生物力学和临床研究结果均令人鼓舞,本文就其应用研究现状进行了综述。     

Lumbar intervertebral disc and ligament deformations measured in vivo

The physiologic deformations of the anterior and posterior margins of the annulus fibrosus and the interspinous ligaments were defined in flexion and extension by accurate measurements taken from lateral roentgenograms of the lumbar spines of 11 normal males. The anterior and posterior disc heights were shown to compress and extend up to 35% and 60%, respectively, while the interspinous distance extended up to 369%. In relation to the known mechanical characteristics in vitro, these deformations implied that the soft-tissue elements were lax or in compression during part of the range of motion. Significantly, the interspinous ligament could be active only in the extremes of flexion. These data provide basic information for further studies of the function of the soft parts of the intervertebral joints.     

Dynamic lumbar stabilization with the Wallis interspinous implant

The primary goal of the Wallis system is to relieve or prevent low back pain that accompanies intervertebral segment (IVS) instability by increasing stiffness of the mobile segment, and unloading the disc and facet joints. Furthermore, restoring a more physiological biomechanical environment to the degenerate lumbar segment with the Wallis implant may foster healing of the disc and slow the degenerative cascade of adjacent segments. The implant, consisting of an interspinous process spacer that limits extension and two flexion-limiting bands, is intended to improve the stability of the treated intervertebral lumbar segment while preserving its mobility and local lordosis. Because the operation leaves all the anatomical elements intact except for the interspinous ligament, the entire range of other surgical options remains open, including more invasive surgical solutions such as total disc replacement or fusion. Most often associated with decompressive procedures, i.e., discectomy, undercutting to enlarge the spinal canal, or both, intervertebral stabilization using the Wallis implant takes less than 15 minutes. This stabilizing procedure is detailed in the present paper.     

Biomechanical effects of sequential resection of the posterior ligamentous complex on intradiscal pressure and resistance to compression forces

ObjectiveThe aim of this biomechanical experimental study was to evaluate the resistance of each posterior ligamentous complex structure of the thoracic and lumbar spine to compression forces and to measure the shifting load to the intervertebral disc when each PLC structure was interrupted.MethodThe study was conducted on 4 groups for thoracic and lumbar region as intact, supraspinous ligament interrupted, interspinous ligament/ligamentum flavum combination interrupted and facet joint capsule interrupted. Pre and post anterior vertebral body height, the highest compression force and pressure changes in the intervertebral disc during 40 N loading were measured.ResultsA significantly different degree of resistance to compression force was determined in each posterior ligamentous complex structure in the thoracic and lumbar spine samples. The combination of interspinous ligament and ligamentum flavum was found to be the most effective structure to resist compression forces (p = 0.001 in both groups). The effect of the supraspinous ligament in thoracic and lumbar segments was found to be similar to that of the interspinous ligament and ligamentum flavum combination (p = 0.008 and p = 0.006, respectively). The least effective structure was observed to be the facet joint capsule. Compression forces were significantly increased in the intervertebral disc as a result of the disruption of supraspinous ligament (p = 0.0032 and p = 0.0029, respectively in thoracic and lumbar segments) and combination of interspinous ligament/ligamentum flavum (p = 0.0019 and p = 0.0021, respectively in thoracic and lumbar segments).ConclusionThe interspinous ligament/ligamentum flavum combination and supraspinous ligament are the largest contributor to resisting applied compression moments in the sheep thoracic and lumbar spine. As a result of the loss of resistance to compression forces, there will be a shift of a great proportion of this force onto the intervertebral disc.Level of evidenceLevel V.     

The height of intervertebral foramen in operative treatment of isthmic spondylolisthesis

49 patients with spondylolisthesis isthmica were treated in the years 1991-2006. The age of patients varied between 21 and 65 years, 43.7 year on average. Two stages operative protocol consisted of reduction of the slip by pedicular implant and anterior interbody fusion with the cages was used. The evaluation was based on x-rays height of the lumbar intervertebral foramen and posterior disc height in the 2 distal lumbar vertebrae pre and post operatively. This results showed clearly a decrease of both these values on the level of the slip, demonstrating the lumbar intervertebral stenosis. Te operative procedure decomprssed the lumbar intervertebral foramen and increased both values evaluated Postoperatively in the neighbor vertebrae a height lumbar intervertebral foramen was increased but posterior disc height a unchanged.     

In-Space经皮棘突间撑开系统治疗腰椎不稳症的初步效果分析

 目的 探讨In-Space经皮棘突间撑开系统治疗腰椎不稳症的初期临床效果。方法 回顾性分析2009年5月至2011年6月采用In-Space经皮棘突间撑开系统治疗腰椎不稳18例患者资料,男10例,女8例;年龄39～58岁,平均48.6岁;L_3,4 5例,L_4,5 13例。患者均伴有不同程度的腰椎过伸性腰背疼痛症状,并伴有一侧下肢的节段性放射性疼痛,屈曲位时缓解。采用视觉模拟评分(visual analogue scale,VAS)对手术前后疼痛进行评估;采用Oswestry功能障碍指数(Oswestry disability index,ODI)对手术前后腰椎功能进行评价。测量术前及术后手术节段棘突间距离、椎间隙前后缘高度、椎间孔高度和宽度、前凸角以及活动度,并进行比较。结果 18例患者均获得随访,随访时间18～36个月,平均(25±2.9)个月。术后6周及末次随访VAS评分为(3.1±1.3)分和(1.5±0.8)分,与术前(7.9±2.1)分比较,差异有统计学意义;术后6周及末次随访ODI为54.7%±14.8%和10.1%±2.5%,与术前82.1%±13.1%比较差异有统计学意义。术后棘突间距离为(9.29±1.43) mm,椎间隙后缘高度为(11.28±0.85) mm,椎间孔高度和宽度分别为(21.27±1.01) mm和(10.83±0.73) mm;节段前凸角及节段活动度分别为7.62°±0.74°和6.34°±0.81°。患者切口均一期愈合,无一例发生棘突骨折、脊髓损伤、脑脊液漏及装置移位、脱出等并发症。结论 In-Space棘突间撑开系统治疗腰椎不稳退行性疾病简便安全,初期随访疗效良好。     

Poroelastic analysis of lumbar spinal stability in combined compression and anterior shear

OBJECTIVE: A three-dimensional poroelastic finite element (FE) L2-L3 model was developed to study lumbar spinal instability and intrinsic parameters in the intervertebral disc (IVD). METHODS: The FE model took into consideration poroelasticity of the IVD and viscoelasticity of the annulus fibers and ligaments to predict the time-dependent behavior. To simulate a holding task, the motion segment was subjected to a combined loading of constant compressive load (1600 N) and anterior shear (200 N) for 2 hours, and the role of facet joints and ligaments in the biomechanical response was investigated by removal of unilateral/bilateral facets, posterior ligaments (supraspinous and interspinous), and facets and ligaments. RESULTS: The results show the stabilizing role of the facets and ligaments in resisting anterior shear and sagittal rotation under combined loading over time. The main pathway of fluid movement was found to permeate through the central region of the endplate, and the fluid diffusion occurred earlier at the posterior nucleus than the anterior nucleus. The fluid loss from the nucleus dictated the time-dependent motion under the sustained loading, whereas the intrinsic properties of ligaments/annulus fibers played a role only in the early stage of the loading. CONCLUSION: The predicted results using poroelastic elements provide new insight into the IVD in providing the spinal stiffness under combined loading.     

Analysis of rabbit intervertebral disc physiology based on water metabolism. I. Factors influencing metabolism of the normal intervertebral discs

Basic factors influencing the metabolism of intervertebral discs of rabbits were quantitatively analyzed based on the water metabolism. The blood flow surrounding the intervertebral disc was calculated using pharmacokinetic concepts from the data obtained by time-related tritiated water distribution analyses. The blood flow was estimated as 0.056 (mg/min/mg tissue) in the anterior annulus, 0.106 in the posterior annulus, 0.120 in the lateral annulus, and 0.084 in the nucleus pulposus, respectively (Experiment 1). Water content and fixed charge density in the intervertebral disc fractions also were measured (Experiment 2). The cations and uncharged small solutes transported into the disc tissue ranged in descending order from nucleus pulposus, lateral annulus, posterior annulus, to anterior annulus. The authors also calculated theoretically the swelling pressure of the proteoglycan in the intervertebral disc fractions from the results of Experiment 2. It was concluded that swelling pressure was highest in the nucleus pulposus, and lowest in the anterior annulus. The water in the posterior annulus is less exchangeable than in the other disc tissue fractions.